diff.con commit Documentation: enable compat-mode for Asciidoctor (b072e0a)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "config.h"
   6#include "tempfile.h"
   7#include "quote.h"
   8#include "diff.h"
   9#include "diffcore.h"
  10#include "delta.h"
  11#include "xdiff-interface.h"
  12#include "color.h"
  13#include "attr.h"
  14#include "run-command.h"
  15#include "utf8.h"
  16#include "userdiff.h"
  17#include "submodule-config.h"
  18#include "submodule.h"
  19#include "hashmap.h"
  20#include "ll-merge.h"
  21#include "string-list.h"
  22#include "argv-array.h"
  23#include "graph.h"
  24#include "packfile.h"
  25
  26#ifdef NO_FAST_WORKING_DIRECTORY
  27#define FAST_WORKING_DIRECTORY 0
  28#else
  29#define FAST_WORKING_DIRECTORY 1
  30#endif
  31
  32static int diff_detect_rename_default;
  33static int diff_indent_heuristic = 1;
  34static int diff_rename_limit_default = 400;
  35static int diff_suppress_blank_empty;
  36static int diff_use_color_default = -1;
  37static int diff_color_moved_default;
  38static int diff_context_default = 3;
  39static int diff_interhunk_context_default;
  40static const char *diff_word_regex_cfg;
  41static const char *external_diff_cmd_cfg;
  42static const char *diff_order_file_cfg;
  43int diff_auto_refresh_index = 1;
  44static int diff_mnemonic_prefix;
  45static int diff_no_prefix;
  46static int diff_stat_graph_width;
  47static int diff_dirstat_permille_default = 30;
  48static struct diff_options default_diff_options;
  49static long diff_algorithm;
  50static unsigned ws_error_highlight_default = WSEH_NEW;
  51
  52static char diff_colors[][COLOR_MAXLEN] = {
  53        GIT_COLOR_RESET,
  54        GIT_COLOR_NORMAL,       /* CONTEXT */
  55        GIT_COLOR_BOLD,         /* METAINFO */
  56        GIT_COLOR_CYAN,         /* FRAGINFO */
  57        GIT_COLOR_RED,          /* OLD */
  58        GIT_COLOR_GREEN,        /* NEW */
  59        GIT_COLOR_YELLOW,       /* COMMIT */
  60        GIT_COLOR_BG_RED,       /* WHITESPACE */
  61        GIT_COLOR_NORMAL,       /* FUNCINFO */
  62        GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  63        GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  64        GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  65        GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  66        GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  67        GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  68        GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  69        GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  70};
  71
  72static NORETURN void die_want_option(const char *option_name)
  73{
  74        die(_("option '%s' requires a value"), option_name);
  75}
  76
  77static int parse_diff_color_slot(const char *var)
  78{
  79        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  80                return DIFF_CONTEXT;
  81        if (!strcasecmp(var, "meta"))
  82                return DIFF_METAINFO;
  83        if (!strcasecmp(var, "frag"))
  84                return DIFF_FRAGINFO;
  85        if (!strcasecmp(var, "old"))
  86                return DIFF_FILE_OLD;
  87        if (!strcasecmp(var, "new"))
  88                return DIFF_FILE_NEW;
  89        if (!strcasecmp(var, "commit"))
  90                return DIFF_COMMIT;
  91        if (!strcasecmp(var, "whitespace"))
  92                return DIFF_WHITESPACE;
  93        if (!strcasecmp(var, "func"))
  94                return DIFF_FUNCINFO;
  95        if (!strcasecmp(var, "oldmoved"))
  96                return DIFF_FILE_OLD_MOVED;
  97        if (!strcasecmp(var, "oldmovedalternative"))
  98                return DIFF_FILE_OLD_MOVED_ALT;
  99        if (!strcasecmp(var, "oldmoveddimmed"))
 100                return DIFF_FILE_OLD_MOVED_DIM;
 101        if (!strcasecmp(var, "oldmovedalternativedimmed"))
 102                return DIFF_FILE_OLD_MOVED_ALT_DIM;
 103        if (!strcasecmp(var, "newmoved"))
 104                return DIFF_FILE_NEW_MOVED;
 105        if (!strcasecmp(var, "newmovedalternative"))
 106                return DIFF_FILE_NEW_MOVED_ALT;
 107        if (!strcasecmp(var, "newmoveddimmed"))
 108                return DIFF_FILE_NEW_MOVED_DIM;
 109        if (!strcasecmp(var, "newmovedalternativedimmed"))
 110                return DIFF_FILE_NEW_MOVED_ALT_DIM;
 111        return -1;
 112}
 113
 114static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 115                                struct strbuf *errmsg)
 116{
 117        char *params_copy = xstrdup(params_string);
 118        struct string_list params = STRING_LIST_INIT_NODUP;
 119        int ret = 0;
 120        int i;
 121
 122        if (*params_copy)
 123                string_list_split_in_place(&params, params_copy, ',', -1);
 124        for (i = 0; i < params.nr; i++) {
 125                const char *p = params.items[i].string;
 126                if (!strcmp(p, "changes")) {
 127                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 128                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 129                } else if (!strcmp(p, "lines")) {
 130                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 131                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 132                } else if (!strcmp(p, "files")) {
 133                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 134                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 135                } else if (!strcmp(p, "noncumulative")) {
 136                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 137                } else if (!strcmp(p, "cumulative")) {
 138                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 139                } else if (isdigit(*p)) {
 140                        char *end;
 141                        int permille = strtoul(p, &end, 10) * 10;
 142                        if (*end == '.' && isdigit(*++end)) {
 143                                /* only use first digit */
 144                                permille += *end - '0';
 145                                /* .. and ignore any further digits */
 146                                while (isdigit(*++end))
 147                                        ; /* nothing */
 148                        }
 149                        if (!*end)
 150                                options->dirstat_permille = permille;
 151                        else {
 152                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 153                                            p);
 154                                ret++;
 155                        }
 156                } else {
 157                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 158                        ret++;
 159                }
 160
 161        }
 162        string_list_clear(&params, 0);
 163        free(params_copy);
 164        return ret;
 165}
 166
 167static int parse_submodule_params(struct diff_options *options, const char *value)
 168{
 169        if (!strcmp(value, "log"))
 170                options->submodule_format = DIFF_SUBMODULE_LOG;
 171        else if (!strcmp(value, "short"))
 172                options->submodule_format = DIFF_SUBMODULE_SHORT;
 173        else if (!strcmp(value, "diff"))
 174                options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 175        else
 176                return -1;
 177        return 0;
 178}
 179
 180static int git_config_rename(const char *var, const char *value)
 181{
 182        if (!value)
 183                return DIFF_DETECT_RENAME;
 184        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 185                return  DIFF_DETECT_COPY;
 186        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 187}
 188
 189long parse_algorithm_value(const char *value)
 190{
 191        if (!value)
 192                return -1;
 193        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 194                return 0;
 195        else if (!strcasecmp(value, "minimal"))
 196                return XDF_NEED_MINIMAL;
 197        else if (!strcasecmp(value, "patience"))
 198                return XDF_PATIENCE_DIFF;
 199        else if (!strcasecmp(value, "histogram"))
 200                return XDF_HISTOGRAM_DIFF;
 201        return -1;
 202}
 203
 204static int parse_one_token(const char **arg, const char *token)
 205{
 206        const char *rest;
 207        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 208                *arg = rest;
 209                return 1;
 210        }
 211        return 0;
 212}
 213
 214static int parse_ws_error_highlight(const char *arg)
 215{
 216        const char *orig_arg = arg;
 217        unsigned val = 0;
 218
 219        while (*arg) {
 220                if (parse_one_token(&arg, "none"))
 221                        val = 0;
 222                else if (parse_one_token(&arg, "default"))
 223                        val = WSEH_NEW;
 224                else if (parse_one_token(&arg, "all"))
 225                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 226                else if (parse_one_token(&arg, "new"))
 227                        val |= WSEH_NEW;
 228                else if (parse_one_token(&arg, "old"))
 229                        val |= WSEH_OLD;
 230                else if (parse_one_token(&arg, "context"))
 231                        val |= WSEH_CONTEXT;
 232                else {
 233                        return -1 - (int)(arg - orig_arg);
 234                }
 235                if (*arg)
 236                        arg++;
 237        }
 238        return val;
 239}
 240
 241/*
 242 * These are to give UI layer defaults.
 243 * The core-level commands such as git-diff-files should
 244 * never be affected by the setting of diff.renames
 245 * the user happens to have in the configuration file.
 246 */
 247void init_diff_ui_defaults(void)
 248{
 249        diff_detect_rename_default = 1;
 250}
 251
 252int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 253{
 254        if (!strcmp(var, "diff.indentheuristic"))
 255                diff_indent_heuristic = git_config_bool(var, value);
 256        return 0;
 257}
 258
 259static int parse_color_moved(const char *arg)
 260{
 261        switch (git_parse_maybe_bool(arg)) {
 262        case 0:
 263                return COLOR_MOVED_NO;
 264        case 1:
 265                return COLOR_MOVED_DEFAULT;
 266        default:
 267                break;
 268        }
 269
 270        if (!strcmp(arg, "no"))
 271                return COLOR_MOVED_NO;
 272        else if (!strcmp(arg, "plain"))
 273                return COLOR_MOVED_PLAIN;
 274        else if (!strcmp(arg, "zebra"))
 275                return COLOR_MOVED_ZEBRA;
 276        else if (!strcmp(arg, "default"))
 277                return COLOR_MOVED_DEFAULT;
 278        else if (!strcmp(arg, "dimmed_zebra"))
 279                return COLOR_MOVED_ZEBRA_DIM;
 280        else
 281                return error(_("color moved setting must be one of 'no', 'default', 'zebra', 'dimmed_zebra', 'plain'"));
 282}
 283
 284int git_diff_ui_config(const char *var, const char *value, void *cb)
 285{
 286        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 287                diff_use_color_default = git_config_colorbool(var, value);
 288                return 0;
 289        }
 290        if (!strcmp(var, "diff.colormoved")) {
 291                int cm = parse_color_moved(value);
 292                if (cm < 0)
 293                        return -1;
 294                diff_color_moved_default = cm;
 295                return 0;
 296        }
 297        if (!strcmp(var, "diff.context")) {
 298                diff_context_default = git_config_int(var, value);
 299                if (diff_context_default < 0)
 300                        return -1;
 301                return 0;
 302        }
 303        if (!strcmp(var, "diff.interhunkcontext")) {
 304                diff_interhunk_context_default = git_config_int(var, value);
 305                if (diff_interhunk_context_default < 0)
 306                        return -1;
 307                return 0;
 308        }
 309        if (!strcmp(var, "diff.renames")) {
 310                diff_detect_rename_default = git_config_rename(var, value);
 311                return 0;
 312        }
 313        if (!strcmp(var, "diff.autorefreshindex")) {
 314                diff_auto_refresh_index = git_config_bool(var, value);
 315                return 0;
 316        }
 317        if (!strcmp(var, "diff.mnemonicprefix")) {
 318                diff_mnemonic_prefix = git_config_bool(var, value);
 319                return 0;
 320        }
 321        if (!strcmp(var, "diff.noprefix")) {
 322                diff_no_prefix = git_config_bool(var, value);
 323                return 0;
 324        }
 325        if (!strcmp(var, "diff.statgraphwidth")) {
 326                diff_stat_graph_width = git_config_int(var, value);
 327                return 0;
 328        }
 329        if (!strcmp(var, "diff.external"))
 330                return git_config_string(&external_diff_cmd_cfg, var, value);
 331        if (!strcmp(var, "diff.wordregex"))
 332                return git_config_string(&diff_word_regex_cfg, var, value);
 333        if (!strcmp(var, "diff.orderfile"))
 334                return git_config_pathname(&diff_order_file_cfg, var, value);
 335
 336        if (!strcmp(var, "diff.ignoresubmodules"))
 337                handle_ignore_submodules_arg(&default_diff_options, value);
 338
 339        if (!strcmp(var, "diff.submodule")) {
 340                if (parse_submodule_params(&default_diff_options, value))
 341                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 342                                value);
 343                return 0;
 344        }
 345
 346        if (!strcmp(var, "diff.algorithm")) {
 347                diff_algorithm = parse_algorithm_value(value);
 348                if (diff_algorithm < 0)
 349                        return -1;
 350                return 0;
 351        }
 352
 353        if (!strcmp(var, "diff.wserrorhighlight")) {
 354                int val = parse_ws_error_highlight(value);
 355                if (val < 0)
 356                        return -1;
 357                ws_error_highlight_default = val;
 358                return 0;
 359        }
 360
 361        if (git_color_config(var, value, cb) < 0)
 362                return -1;
 363
 364        return git_diff_basic_config(var, value, cb);
 365}
 366
 367int git_diff_basic_config(const char *var, const char *value, void *cb)
 368{
 369        const char *name;
 370
 371        if (!strcmp(var, "diff.renamelimit")) {
 372                diff_rename_limit_default = git_config_int(var, value);
 373                return 0;
 374        }
 375
 376        if (userdiff_config(var, value) < 0)
 377                return -1;
 378
 379        if (skip_prefix(var, "diff.color.", &name) ||
 380            skip_prefix(var, "color.diff.", &name)) {
 381                int slot = parse_diff_color_slot(name);
 382                if (slot < 0)
 383                        return 0;
 384                if (!value)
 385                        return config_error_nonbool(var);
 386                return color_parse(value, diff_colors[slot]);
 387        }
 388
 389        /* like GNU diff's --suppress-blank-empty option  */
 390        if (!strcmp(var, "diff.suppressblankempty") ||
 391                        /* for backwards compatibility */
 392                        !strcmp(var, "diff.suppress-blank-empty")) {
 393                diff_suppress_blank_empty = git_config_bool(var, value);
 394                return 0;
 395        }
 396
 397        if (!strcmp(var, "diff.dirstat")) {
 398                struct strbuf errmsg = STRBUF_INIT;
 399                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 400                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 401                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 402                                errmsg.buf);
 403                strbuf_release(&errmsg);
 404                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 405                return 0;
 406        }
 407
 408        if (git_diff_heuristic_config(var, value, cb) < 0)
 409                return -1;
 410
 411        return git_default_config(var, value, cb);
 412}
 413
 414static char *quote_two(const char *one, const char *two)
 415{
 416        int need_one = quote_c_style(one, NULL, NULL, 1);
 417        int need_two = quote_c_style(two, NULL, NULL, 1);
 418        struct strbuf res = STRBUF_INIT;
 419
 420        if (need_one + need_two) {
 421                strbuf_addch(&res, '"');
 422                quote_c_style(one, &res, NULL, 1);
 423                quote_c_style(two, &res, NULL, 1);
 424                strbuf_addch(&res, '"');
 425        } else {
 426                strbuf_addstr(&res, one);
 427                strbuf_addstr(&res, two);
 428        }
 429        return strbuf_detach(&res, NULL);
 430}
 431
 432static const char *external_diff(void)
 433{
 434        static const char *external_diff_cmd = NULL;
 435        static int done_preparing = 0;
 436
 437        if (done_preparing)
 438                return external_diff_cmd;
 439        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 440        if (!external_diff_cmd)
 441                external_diff_cmd = external_diff_cmd_cfg;
 442        done_preparing = 1;
 443        return external_diff_cmd;
 444}
 445
 446/*
 447 * Keep track of files used for diffing. Sometimes such an entry
 448 * refers to a temporary file, sometimes to an existing file, and
 449 * sometimes to "/dev/null".
 450 */
 451static struct diff_tempfile {
 452        /*
 453         * filename external diff should read from, or NULL if this
 454         * entry is currently not in use:
 455         */
 456        const char *name;
 457
 458        char hex[GIT_MAX_HEXSZ + 1];
 459        char mode[10];
 460
 461        /*
 462         * If this diff_tempfile instance refers to a temporary file,
 463         * this tempfile object is used to manage its lifetime.
 464         */
 465        struct tempfile *tempfile;
 466} diff_temp[2];
 467
 468struct emit_callback {
 469        int color_diff;
 470        unsigned ws_rule;
 471        int blank_at_eof_in_preimage;
 472        int blank_at_eof_in_postimage;
 473        int lno_in_preimage;
 474        int lno_in_postimage;
 475        const char **label_path;
 476        struct diff_words_data *diff_words;
 477        struct diff_options *opt;
 478        struct strbuf *header;
 479};
 480
 481static int count_lines(const char *data, int size)
 482{
 483        int count, ch, completely_empty = 1, nl_just_seen = 0;
 484        count = 0;
 485        while (0 < size--) {
 486                ch = *data++;
 487                if (ch == '\n') {
 488                        count++;
 489                        nl_just_seen = 1;
 490                        completely_empty = 0;
 491                }
 492                else {
 493                        nl_just_seen = 0;
 494                        completely_empty = 0;
 495                }
 496        }
 497        if (completely_empty)
 498                return 0;
 499        if (!nl_just_seen)
 500                count++; /* no trailing newline */
 501        return count;
 502}
 503
 504static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 505{
 506        if (!DIFF_FILE_VALID(one)) {
 507                mf->ptr = (char *)""; /* does not matter */
 508                mf->size = 0;
 509                return 0;
 510        }
 511        else if (diff_populate_filespec(one, 0))
 512                return -1;
 513
 514        mf->ptr = one->data;
 515        mf->size = one->size;
 516        return 0;
 517}
 518
 519/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 520static unsigned long diff_filespec_size(struct diff_filespec *one)
 521{
 522        if (!DIFF_FILE_VALID(one))
 523                return 0;
 524        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 525        return one->size;
 526}
 527
 528static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 529{
 530        char *ptr = mf->ptr;
 531        long size = mf->size;
 532        int cnt = 0;
 533
 534        if (!size)
 535                return cnt;
 536        ptr += size - 1; /* pointing at the very end */
 537        if (*ptr != '\n')
 538                ; /* incomplete line */
 539        else
 540                ptr--; /* skip the last LF */
 541        while (mf->ptr < ptr) {
 542                char *prev_eol;
 543                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 544                        if (*prev_eol == '\n')
 545                                break;
 546                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 547                        break;
 548                cnt++;
 549                ptr = prev_eol - 1;
 550        }
 551        return cnt;
 552}
 553
 554static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 555                               struct emit_callback *ecbdata)
 556{
 557        int l1, l2, at;
 558        unsigned ws_rule = ecbdata->ws_rule;
 559        l1 = count_trailing_blank(mf1, ws_rule);
 560        l2 = count_trailing_blank(mf2, ws_rule);
 561        if (l2 <= l1) {
 562                ecbdata->blank_at_eof_in_preimage = 0;
 563                ecbdata->blank_at_eof_in_postimage = 0;
 564                return;
 565        }
 566        at = count_lines(mf1->ptr, mf1->size);
 567        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 568
 569        at = count_lines(mf2->ptr, mf2->size);
 570        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 571}
 572
 573static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 574                        int first, const char *line, int len)
 575{
 576        int has_trailing_newline, has_trailing_carriage_return;
 577        int nofirst;
 578        FILE *file = o->file;
 579
 580        fputs(diff_line_prefix(o), file);
 581
 582        if (len == 0) {
 583                has_trailing_newline = (first == '\n');
 584                has_trailing_carriage_return = (!has_trailing_newline &&
 585                                                (first == '\r'));
 586                nofirst = has_trailing_newline || has_trailing_carriage_return;
 587        } else {
 588                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 589                if (has_trailing_newline)
 590                        len--;
 591                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 592                if (has_trailing_carriage_return)
 593                        len--;
 594                nofirst = 0;
 595        }
 596
 597        if (len || !nofirst) {
 598                fputs(set, file);
 599                if (!nofirst)
 600                        fputc(first, file);
 601                fwrite(line, len, 1, file);
 602                fputs(reset, file);
 603        }
 604        if (has_trailing_carriage_return)
 605                fputc('\r', file);
 606        if (has_trailing_newline)
 607                fputc('\n', file);
 608}
 609
 610static void emit_line(struct diff_options *o, const char *set, const char *reset,
 611                      const char *line, int len)
 612{
 613        emit_line_0(o, set, reset, line[0], line+1, len-1);
 614}
 615
 616enum diff_symbol {
 617        DIFF_SYMBOL_BINARY_DIFF_HEADER,
 618        DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 619        DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 620        DIFF_SYMBOL_BINARY_DIFF_BODY,
 621        DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 622        DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 623        DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 624        DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 625        DIFF_SYMBOL_STATS_LINE,
 626        DIFF_SYMBOL_WORD_DIFF,
 627        DIFF_SYMBOL_STAT_SEP,
 628        DIFF_SYMBOL_SUMMARY,
 629        DIFF_SYMBOL_SUBMODULE_ADD,
 630        DIFF_SYMBOL_SUBMODULE_DEL,
 631        DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 632        DIFF_SYMBOL_SUBMODULE_MODIFIED,
 633        DIFF_SYMBOL_SUBMODULE_HEADER,
 634        DIFF_SYMBOL_SUBMODULE_ERROR,
 635        DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 636        DIFF_SYMBOL_REWRITE_DIFF,
 637        DIFF_SYMBOL_BINARY_FILES,
 638        DIFF_SYMBOL_HEADER,
 639        DIFF_SYMBOL_FILEPAIR_PLUS,
 640        DIFF_SYMBOL_FILEPAIR_MINUS,
 641        DIFF_SYMBOL_WORDS_PORCELAIN,
 642        DIFF_SYMBOL_WORDS,
 643        DIFF_SYMBOL_CONTEXT,
 644        DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 645        DIFF_SYMBOL_PLUS,
 646        DIFF_SYMBOL_MINUS,
 647        DIFF_SYMBOL_NO_LF_EOF,
 648        DIFF_SYMBOL_CONTEXT_FRAGINFO,
 649        DIFF_SYMBOL_CONTEXT_MARKER,
 650        DIFF_SYMBOL_SEPARATOR
 651};
 652/*
 653 * Flags for content lines:
 654 * 0..12 are whitespace rules
 655 * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 656 * 16 is marking if the line is blank at EOF
 657 */
 658#define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 659#define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 660#define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 661#define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 662#define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 663
 664/*
 665 * This struct is used when we need to buffer the output of the diff output.
 666 *
 667 * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 668 * into the pre/post image file. This pointer could be a union with the
 669 * line pointer. By storing an offset into the file instead of the literal line,
 670 * we can decrease the memory footprint for the buffered output. At first we
 671 * may want to only have indirection for the content lines, but we could also
 672 * enhance the state for emitting prefabricated lines, e.g. the similarity
 673 * score line or hunk/file headers would only need to store a number or path
 674 * and then the output can be constructed later on depending on state.
 675 */
 676struct emitted_diff_symbol {
 677        const char *line;
 678        int len;
 679        int flags;
 680        enum diff_symbol s;
 681};
 682#define EMITTED_DIFF_SYMBOL_INIT {NULL}
 683
 684struct emitted_diff_symbols {
 685        struct emitted_diff_symbol *buf;
 686        int nr, alloc;
 687};
 688#define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 689
 690static void append_emitted_diff_symbol(struct diff_options *o,
 691                                       struct emitted_diff_symbol *e)
 692{
 693        struct emitted_diff_symbol *f;
 694
 695        ALLOC_GROW(o->emitted_symbols->buf,
 696                   o->emitted_symbols->nr + 1,
 697                   o->emitted_symbols->alloc);
 698        f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 699
 700        memcpy(f, e, sizeof(struct emitted_diff_symbol));
 701        f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 702}
 703
 704struct moved_entry {
 705        struct hashmap_entry ent;
 706        const struct emitted_diff_symbol *es;
 707        struct moved_entry *next_line;
 708};
 709
 710static int next_byte(const char **cp, const char **endp,
 711                     const struct diff_options *diffopt)
 712{
 713        int retval;
 714
 715        if (*cp > *endp)
 716                return -1;
 717
 718        if (isspace(**cp)) {
 719                if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_CHANGE)) {
 720                        while (*cp < *endp && isspace(**cp))
 721                                (*cp)++;
 722                        /*
 723                         * After skipping a couple of whitespaces,
 724                         * we still have to account for one space.
 725                         */
 726                        return (int)' ';
 727                }
 728
 729                if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE)) {
 730                        while (*cp < *endp && isspace(**cp))
 731                                (*cp)++;
 732                        /* return the first non-ws character via the usual below */
 733                }
 734        }
 735
 736        retval = (unsigned char)(**cp);
 737        (*cp)++;
 738        return retval;
 739}
 740
 741static int moved_entry_cmp(const struct diff_options *diffopt,
 742                           const struct moved_entry *a,
 743                           const struct moved_entry *b,
 744                           const void *keydata)
 745{
 746        const char *ap = a->es->line, *ae = a->es->line + a->es->len;
 747        const char *bp = b->es->line, *be = b->es->line + b->es->len;
 748
 749        if (!(diffopt->xdl_opts & XDF_WHITESPACE_FLAGS))
 750                return a->es->len != b->es->len  || memcmp(ap, bp, a->es->len);
 751
 752        if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_AT_EOL)) {
 753                while (ae > ap && isspace(*ae))
 754                        ae--;
 755                while (be > bp && isspace(*be))
 756                        be--;
 757        }
 758
 759        while (1) {
 760                int ca, cb;
 761                ca = next_byte(&ap, &ae, diffopt);
 762                cb = next_byte(&bp, &be, diffopt);
 763                if (ca != cb)
 764                        return 1;
 765                if (ca < 0)
 766                        return 0;
 767        }
 768}
 769
 770static unsigned get_string_hash(struct emitted_diff_symbol *es, struct diff_options *o)
 771{
 772        if (o->xdl_opts & XDF_WHITESPACE_FLAGS) {
 773                static struct strbuf sb = STRBUF_INIT;
 774                const char *ap = es->line, *ae = es->line + es->len;
 775                int c;
 776
 777                strbuf_reset(&sb);
 778                while (ae > ap && isspace(*ae))
 779                        ae--;
 780                while ((c = next_byte(&ap, &ae, o)) > 0)
 781                        strbuf_addch(&sb, c);
 782
 783                return memhash(sb.buf, sb.len);
 784        } else {
 785                return memhash(es->line, es->len);
 786        }
 787}
 788
 789static struct moved_entry *prepare_entry(struct diff_options *o,
 790                                         int line_no)
 791{
 792        struct moved_entry *ret = xmalloc(sizeof(*ret));
 793        struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 794
 795        ret->ent.hash = get_string_hash(l, o);
 796        ret->es = l;
 797        ret->next_line = NULL;
 798
 799        return ret;
 800}
 801
 802static void add_lines_to_move_detection(struct diff_options *o,
 803                                        struct hashmap *add_lines,
 804                                        struct hashmap *del_lines)
 805{
 806        struct moved_entry *prev_line = NULL;
 807
 808        int n;
 809        for (n = 0; n < o->emitted_symbols->nr; n++) {
 810                struct hashmap *hm;
 811                struct moved_entry *key;
 812
 813                switch (o->emitted_symbols->buf[n].s) {
 814                case DIFF_SYMBOL_PLUS:
 815                        hm = add_lines;
 816                        break;
 817                case DIFF_SYMBOL_MINUS:
 818                        hm = del_lines;
 819                        break;
 820                default:
 821                        prev_line = NULL;
 822                        continue;
 823                }
 824
 825                key = prepare_entry(o, n);
 826                if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 827                        prev_line->next_line = key;
 828
 829                hashmap_add(hm, key);
 830                prev_line = key;
 831        }
 832}
 833
 834static int shrink_potential_moved_blocks(struct moved_entry **pmb,
 835                                         int pmb_nr)
 836{
 837        int lp, rp;
 838
 839        /* Shrink the set of potential block to the remaining running */
 840        for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
 841                while (lp < pmb_nr && pmb[lp])
 842                        lp++;
 843                /* lp points at the first NULL now */
 844
 845                while (rp > -1 && !pmb[rp])
 846                        rp--;
 847                /* rp points at the last non-NULL */
 848
 849                if (lp < pmb_nr && rp > -1 && lp < rp) {
 850                        pmb[lp] = pmb[rp];
 851                        pmb[rp] = NULL;
 852                        rp--;
 853                        lp++;
 854                }
 855        }
 856
 857        /* Remember the number of running sets */
 858        return rp + 1;
 859}
 860
 861/*
 862 * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
 863 *
 864 * Otherwise, if the last block has fewer alphanumeric characters than
 865 * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
 866 * that block.
 867 *
 868 * The last block consists of the (n - block_length)'th line up to but not
 869 * including the nth line.
 870 *
 871 * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
 872 * Think of a way to unify them.
 873 */
 874static void adjust_last_block(struct diff_options *o, int n, int block_length)
 875{
 876        int i, alnum_count = 0;
 877        if (o->color_moved == COLOR_MOVED_PLAIN)
 878                return;
 879        for (i = 1; i < block_length + 1; i++) {
 880                const char *c = o->emitted_symbols->buf[n - i].line;
 881                for (; *c; c++) {
 882                        if (!isalnum(*c))
 883                                continue;
 884                        alnum_count++;
 885                        if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
 886                                return;
 887                }
 888        }
 889        for (i = 1; i < block_length + 1; i++)
 890                o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
 891}
 892
 893/* Find blocks of moved code, delegate actual coloring decision to helper */
 894static void mark_color_as_moved(struct diff_options *o,
 895                                struct hashmap *add_lines,
 896                                struct hashmap *del_lines)
 897{
 898        struct moved_entry **pmb = NULL; /* potentially moved blocks */
 899        int pmb_nr = 0, pmb_alloc = 0;
 900        int n, flipped_block = 1, block_length = 0;
 901
 902
 903        for (n = 0; n < o->emitted_symbols->nr; n++) {
 904                struct hashmap *hm = NULL;
 905                struct moved_entry *key;
 906                struct moved_entry *match = NULL;
 907                struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 908                int i;
 909
 910                switch (l->s) {
 911                case DIFF_SYMBOL_PLUS:
 912                        hm = del_lines;
 913                        key = prepare_entry(o, n);
 914                        match = hashmap_get(hm, key, o);
 915                        free(key);
 916                        break;
 917                case DIFF_SYMBOL_MINUS:
 918                        hm = add_lines;
 919                        key = prepare_entry(o, n);
 920                        match = hashmap_get(hm, key, o);
 921                        free(key);
 922                        break;
 923                default:
 924                        flipped_block = 1;
 925                }
 926
 927                if (!match) {
 928                        adjust_last_block(o, n, block_length);
 929                        pmb_nr = 0;
 930                        block_length = 0;
 931                        continue;
 932                }
 933
 934                l->flags |= DIFF_SYMBOL_MOVED_LINE;
 935
 936                if (o->color_moved == COLOR_MOVED_PLAIN)
 937                        continue;
 938
 939                /* Check any potential block runs, advance each or nullify */
 940                for (i = 0; i < pmb_nr; i++) {
 941                        struct moved_entry *p = pmb[i];
 942                        struct moved_entry *pnext = (p && p->next_line) ?
 943                                        p->next_line : NULL;
 944                        if (pnext && !hm->cmpfn(o, pnext, match, NULL)) {
 945                                pmb[i] = p->next_line;
 946                        } else {
 947                                pmb[i] = NULL;
 948                        }
 949                }
 950
 951                pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
 952
 953                if (pmb_nr == 0) {
 954                        /*
 955                         * The current line is the start of a new block.
 956                         * Setup the set of potential blocks.
 957                         */
 958                        for (; match; match = hashmap_get_next(hm, match)) {
 959                                ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
 960                                pmb[pmb_nr++] = match;
 961                        }
 962
 963                        flipped_block = (flipped_block + 1) % 2;
 964
 965                        adjust_last_block(o, n, block_length);
 966                        block_length = 0;
 967                }
 968
 969                block_length++;
 970
 971                if (flipped_block)
 972                        l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
 973        }
 974        adjust_last_block(o, n, block_length);
 975
 976        free(pmb);
 977}
 978
 979#define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
 980  (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
 981static void dim_moved_lines(struct diff_options *o)
 982{
 983        int n;
 984        for (n = 0; n < o->emitted_symbols->nr; n++) {
 985                struct emitted_diff_symbol *prev = (n != 0) ?
 986                                &o->emitted_symbols->buf[n - 1] : NULL;
 987                struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 988                struct emitted_diff_symbol *next =
 989                                (n < o->emitted_symbols->nr - 1) ?
 990                                &o->emitted_symbols->buf[n + 1] : NULL;
 991
 992                /* Not a plus or minus line? */
 993                if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
 994                        continue;
 995
 996                /* Not a moved line? */
 997                if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
 998                        continue;
 999
1000                /*
1001                 * If prev or next are not a plus or minus line,
1002                 * pretend they don't exist
1003                 */
1004                if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1005                            prev->s != DIFF_SYMBOL_MINUS)
1006                        prev = NULL;
1007                if (next && next->s != DIFF_SYMBOL_PLUS &&
1008                            next->s != DIFF_SYMBOL_MINUS)
1009                        next = NULL;
1010
1011                /* Inside a block? */
1012                if ((prev &&
1013                    (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1014                    (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1015                    (next &&
1016                    (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1017                    (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1018                        l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1019                        continue;
1020                }
1021
1022                /* Check if we are at an interesting bound: */
1023                if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1024                    (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1025                       (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1026                        continue;
1027                if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1028                    (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1029                       (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1030                        continue;
1031
1032                /*
1033                 * The boundary to prev and next are not interesting,
1034                 * so this line is not interesting as a whole
1035                 */
1036                l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1037        }
1038}
1039
1040static void emit_line_ws_markup(struct diff_options *o,
1041                                const char *set, const char *reset,
1042                                const char *line, int len, char sign,
1043                                unsigned ws_rule, int blank_at_eof)
1044{
1045        const char *ws = NULL;
1046
1047        if (o->ws_error_highlight & ws_rule) {
1048                ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1049                if (!*ws)
1050                        ws = NULL;
1051        }
1052
1053        if (!ws)
1054                emit_line_0(o, set, reset, sign, line, len);
1055        else if (blank_at_eof)
1056                /* Blank line at EOF - paint '+' as well */
1057                emit_line_0(o, ws, reset, sign, line, len);
1058        else {
1059                /* Emit just the prefix, then the rest. */
1060                emit_line_0(o, set, reset, sign, "", 0);
1061                ws_check_emit(line, len, ws_rule,
1062                              o->file, set, reset, ws);
1063        }
1064}
1065
1066static void emit_diff_symbol_from_struct(struct diff_options *o,
1067                                         struct emitted_diff_symbol *eds)
1068{
1069        static const char *nneof = " No newline at end of file\n";
1070        const char *context, *reset, *set, *meta, *fraginfo;
1071        struct strbuf sb = STRBUF_INIT;
1072
1073        enum diff_symbol s = eds->s;
1074        const char *line = eds->line;
1075        int len = eds->len;
1076        unsigned flags = eds->flags;
1077
1078        switch (s) {
1079        case DIFF_SYMBOL_NO_LF_EOF:
1080                context = diff_get_color_opt(o, DIFF_CONTEXT);
1081                reset = diff_get_color_opt(o, DIFF_RESET);
1082                putc('\n', o->file);
1083                emit_line_0(o, context, reset, '\\',
1084                            nneof, strlen(nneof));
1085                break;
1086        case DIFF_SYMBOL_SUBMODULE_HEADER:
1087        case DIFF_SYMBOL_SUBMODULE_ERROR:
1088        case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1089        case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1090        case DIFF_SYMBOL_SUMMARY:
1091        case DIFF_SYMBOL_STATS_LINE:
1092        case DIFF_SYMBOL_BINARY_DIFF_BODY:
1093        case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1094                emit_line(o, "", "", line, len);
1095                break;
1096        case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1097        case DIFF_SYMBOL_CONTEXT_MARKER:
1098                context = diff_get_color_opt(o, DIFF_CONTEXT);
1099                reset = diff_get_color_opt(o, DIFF_RESET);
1100                emit_line(o, context, reset, line, len);
1101                break;
1102        case DIFF_SYMBOL_SEPARATOR:
1103                fprintf(o->file, "%s%c",
1104                        diff_line_prefix(o),
1105                        o->line_termination);
1106                break;
1107        case DIFF_SYMBOL_CONTEXT:
1108                set = diff_get_color_opt(o, DIFF_CONTEXT);
1109                reset = diff_get_color_opt(o, DIFF_RESET);
1110                emit_line_ws_markup(o, set, reset, line, len, ' ',
1111                                    flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1112                break;
1113        case DIFF_SYMBOL_PLUS:
1114                switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1115                                 DIFF_SYMBOL_MOVED_LINE_ALT |
1116                                 DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1117                case DIFF_SYMBOL_MOVED_LINE |
1118                     DIFF_SYMBOL_MOVED_LINE_ALT |
1119                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1120                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1121                        break;
1122                case DIFF_SYMBOL_MOVED_LINE |
1123                     DIFF_SYMBOL_MOVED_LINE_ALT:
1124                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1125                        break;
1126                case DIFF_SYMBOL_MOVED_LINE |
1127                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1128                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1129                        break;
1130                case DIFF_SYMBOL_MOVED_LINE:
1131                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1132                        break;
1133                default:
1134                        set = diff_get_color_opt(o, DIFF_FILE_NEW);
1135                }
1136                reset = diff_get_color_opt(o, DIFF_RESET);
1137                emit_line_ws_markup(o, set, reset, line, len, '+',
1138                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1139                                    flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1140                break;
1141        case DIFF_SYMBOL_MINUS:
1142                switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1143                                 DIFF_SYMBOL_MOVED_LINE_ALT |
1144                                 DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1145                case DIFF_SYMBOL_MOVED_LINE |
1146                     DIFF_SYMBOL_MOVED_LINE_ALT |
1147                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1148                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1149                        break;
1150                case DIFF_SYMBOL_MOVED_LINE |
1151                     DIFF_SYMBOL_MOVED_LINE_ALT:
1152                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1153                        break;
1154                case DIFF_SYMBOL_MOVED_LINE |
1155                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1156                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1157                        break;
1158                case DIFF_SYMBOL_MOVED_LINE:
1159                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1160                        break;
1161                default:
1162                        set = diff_get_color_opt(o, DIFF_FILE_OLD);
1163                }
1164                reset = diff_get_color_opt(o, DIFF_RESET);
1165                emit_line_ws_markup(o, set, reset, line, len, '-',
1166                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1167                break;
1168        case DIFF_SYMBOL_WORDS_PORCELAIN:
1169                context = diff_get_color_opt(o, DIFF_CONTEXT);
1170                reset = diff_get_color_opt(o, DIFF_RESET);
1171                emit_line(o, context, reset, line, len);
1172                fputs("~\n", o->file);
1173                break;
1174        case DIFF_SYMBOL_WORDS:
1175                context = diff_get_color_opt(o, DIFF_CONTEXT);
1176                reset = diff_get_color_opt(o, DIFF_RESET);
1177                /*
1178                 * Skip the prefix character, if any.  With
1179                 * diff_suppress_blank_empty, there may be
1180                 * none.
1181                 */
1182                if (line[0] != '\n') {
1183                        line++;
1184                        len--;
1185                }
1186                emit_line(o, context, reset, line, len);
1187                break;
1188        case DIFF_SYMBOL_FILEPAIR_PLUS:
1189                meta = diff_get_color_opt(o, DIFF_METAINFO);
1190                reset = diff_get_color_opt(o, DIFF_RESET);
1191                fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1192                        line, reset,
1193                        strchr(line, ' ') ? "\t" : "");
1194                break;
1195        case DIFF_SYMBOL_FILEPAIR_MINUS:
1196                meta = diff_get_color_opt(o, DIFF_METAINFO);
1197                reset = diff_get_color_opt(o, DIFF_RESET);
1198                fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1199                        line, reset,
1200                        strchr(line, ' ') ? "\t" : "");
1201                break;
1202        case DIFF_SYMBOL_BINARY_FILES:
1203        case DIFF_SYMBOL_HEADER:
1204                fprintf(o->file, "%s", line);
1205                break;
1206        case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1207                fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1208                break;
1209        case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1210                fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1211                break;
1212        case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1213                fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1214                break;
1215        case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1216                fputs(diff_line_prefix(o), o->file);
1217                fputc('\n', o->file);
1218                break;
1219        case DIFF_SYMBOL_REWRITE_DIFF:
1220                fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1221                reset = diff_get_color_opt(o, DIFF_RESET);
1222                emit_line(o, fraginfo, reset, line, len);
1223                break;
1224        case DIFF_SYMBOL_SUBMODULE_ADD:
1225                set = diff_get_color_opt(o, DIFF_FILE_NEW);
1226                reset = diff_get_color_opt(o, DIFF_RESET);
1227                emit_line(o, set, reset, line, len);
1228                break;
1229        case DIFF_SYMBOL_SUBMODULE_DEL:
1230                set = diff_get_color_opt(o, DIFF_FILE_OLD);
1231                reset = diff_get_color_opt(o, DIFF_RESET);
1232                emit_line(o, set, reset, line, len);
1233                break;
1234        case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1235                fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1236                        diff_line_prefix(o), line);
1237                break;
1238        case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1239                fprintf(o->file, "%sSubmodule %s contains modified content\n",
1240                        diff_line_prefix(o), line);
1241                break;
1242        case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1243                emit_line(o, "", "", " 0 files changed\n",
1244                          strlen(" 0 files changed\n"));
1245                break;
1246        case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1247                emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1248                break;
1249        case DIFF_SYMBOL_WORD_DIFF:
1250                fprintf(o->file, "%.*s", len, line);
1251                break;
1252        case DIFF_SYMBOL_STAT_SEP:
1253                fputs(o->stat_sep, o->file);
1254                break;
1255        default:
1256                die("BUG: unknown diff symbol");
1257        }
1258        strbuf_release(&sb);
1259}
1260
1261static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1262                             const char *line, int len, unsigned flags)
1263{
1264        struct emitted_diff_symbol e = {line, len, flags, s};
1265
1266        if (o->emitted_symbols)
1267                append_emitted_diff_symbol(o, &e);
1268        else
1269                emit_diff_symbol_from_struct(o, &e);
1270}
1271
1272void diff_emit_submodule_del(struct diff_options *o, const char *line)
1273{
1274        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1275}
1276
1277void diff_emit_submodule_add(struct diff_options *o, const char *line)
1278{
1279        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1280}
1281
1282void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1283{
1284        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1285                         path, strlen(path), 0);
1286}
1287
1288void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1289{
1290        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1291                         path, strlen(path), 0);
1292}
1293
1294void diff_emit_submodule_header(struct diff_options *o, const char *header)
1295{
1296        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1297                         header, strlen(header), 0);
1298}
1299
1300void diff_emit_submodule_error(struct diff_options *o, const char *err)
1301{
1302        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1303}
1304
1305void diff_emit_submodule_pipethrough(struct diff_options *o,
1306                                     const char *line, int len)
1307{
1308        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1309}
1310
1311static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1312{
1313        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1314              ecbdata->blank_at_eof_in_preimage &&
1315              ecbdata->blank_at_eof_in_postimage &&
1316              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1317              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1318                return 0;
1319        return ws_blank_line(line, len, ecbdata->ws_rule);
1320}
1321
1322static void emit_add_line(const char *reset,
1323                          struct emit_callback *ecbdata,
1324                          const char *line, int len)
1325{
1326        unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1327        if (new_blank_line_at_eof(ecbdata, line, len))
1328                flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1329
1330        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1331}
1332
1333static void emit_del_line(const char *reset,
1334                          struct emit_callback *ecbdata,
1335                          const char *line, int len)
1336{
1337        unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1338        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1339}
1340
1341static void emit_context_line(const char *reset,
1342                              struct emit_callback *ecbdata,
1343                              const char *line, int len)
1344{
1345        unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1346        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1347}
1348
1349static void emit_hunk_header(struct emit_callback *ecbdata,
1350                             const char *line, int len)
1351{
1352        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1353        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1354        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1355        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1356        static const char atat[2] = { '@', '@' };
1357        const char *cp, *ep;
1358        struct strbuf msgbuf = STRBUF_INIT;
1359        int org_len = len;
1360        int i = 1;
1361
1362        /*
1363         * As a hunk header must begin with "@@ -<old>, +<new> @@",
1364         * it always is at least 10 bytes long.
1365         */
1366        if (len < 10 ||
1367            memcmp(line, atat, 2) ||
1368            !(ep = memmem(line + 2, len - 2, atat, 2))) {
1369                emit_diff_symbol(ecbdata->opt,
1370                                 DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1371                return;
1372        }
1373        ep += 2; /* skip over @@ */
1374
1375        /* The hunk header in fraginfo color */
1376        strbuf_addstr(&msgbuf, frag);
1377        strbuf_add(&msgbuf, line, ep - line);
1378        strbuf_addstr(&msgbuf, reset);
1379
1380        /*
1381         * trailing "\r\n"
1382         */
1383        for ( ; i < 3; i++)
1384                if (line[len - i] == '\r' || line[len - i] == '\n')
1385                        len--;
1386
1387        /* blank before the func header */
1388        for (cp = ep; ep - line < len; ep++)
1389                if (*ep != ' ' && *ep != '\t')
1390                        break;
1391        if (ep != cp) {
1392                strbuf_addstr(&msgbuf, context);
1393                strbuf_add(&msgbuf, cp, ep - cp);
1394                strbuf_addstr(&msgbuf, reset);
1395        }
1396
1397        if (ep < line + len) {
1398                strbuf_addstr(&msgbuf, func);
1399                strbuf_add(&msgbuf, ep, line + len - ep);
1400                strbuf_addstr(&msgbuf, reset);
1401        }
1402
1403        strbuf_add(&msgbuf, line + len, org_len - len);
1404        strbuf_complete_line(&msgbuf);
1405        emit_diff_symbol(ecbdata->opt,
1406                         DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1407        strbuf_release(&msgbuf);
1408}
1409
1410static struct diff_tempfile *claim_diff_tempfile(void) {
1411        int i;
1412        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1413                if (!diff_temp[i].name)
1414                        return diff_temp + i;
1415        die("BUG: diff is failing to clean up its tempfiles");
1416}
1417
1418static void remove_tempfile(void)
1419{
1420        int i;
1421        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1422                if (is_tempfile_active(diff_temp[i].tempfile))
1423                        delete_tempfile(&diff_temp[i].tempfile);
1424                diff_temp[i].name = NULL;
1425        }
1426}
1427
1428static void add_line_count(struct strbuf *out, int count)
1429{
1430        switch (count) {
1431        case 0:
1432                strbuf_addstr(out, "0,0");
1433                break;
1434        case 1:
1435                strbuf_addstr(out, "1");
1436                break;
1437        default:
1438                strbuf_addf(out, "1,%d", count);
1439                break;
1440        }
1441}
1442
1443static void emit_rewrite_lines(struct emit_callback *ecb,
1444                               int prefix, const char *data, int size)
1445{
1446        const char *endp = NULL;
1447        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1448
1449        while (0 < size) {
1450                int len;
1451
1452                endp = memchr(data, '\n', size);
1453                len = endp ? (endp - data + 1) : size;
1454                if (prefix != '+') {
1455                        ecb->lno_in_preimage++;
1456                        emit_del_line(reset, ecb, data, len);
1457                } else {
1458                        ecb->lno_in_postimage++;
1459                        emit_add_line(reset, ecb, data, len);
1460                }
1461                size -= len;
1462                data += len;
1463        }
1464        if (!endp)
1465                emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1466}
1467
1468static void emit_rewrite_diff(const char *name_a,
1469                              const char *name_b,
1470                              struct diff_filespec *one,
1471                              struct diff_filespec *two,
1472                              struct userdiff_driver *textconv_one,
1473                              struct userdiff_driver *textconv_two,
1474                              struct diff_options *o)
1475{
1476        int lc_a, lc_b;
1477        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1478        const char *a_prefix, *b_prefix;
1479        char *data_one, *data_two;
1480        size_t size_one, size_two;
1481        struct emit_callback ecbdata;
1482        struct strbuf out = STRBUF_INIT;
1483
1484        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
1485                a_prefix = o->b_prefix;
1486                b_prefix = o->a_prefix;
1487        } else {
1488                a_prefix = o->a_prefix;
1489                b_prefix = o->b_prefix;
1490        }
1491
1492        name_a += (*name_a == '/');
1493        name_b += (*name_b == '/');
1494
1495        strbuf_reset(&a_name);
1496        strbuf_reset(&b_name);
1497        quote_two_c_style(&a_name, a_prefix, name_a, 0);
1498        quote_two_c_style(&b_name, b_prefix, name_b, 0);
1499
1500        size_one = fill_textconv(textconv_one, one, &data_one);
1501        size_two = fill_textconv(textconv_two, two, &data_two);
1502
1503        memset(&ecbdata, 0, sizeof(ecbdata));
1504        ecbdata.color_diff = want_color(o->use_color);
1505        ecbdata.ws_rule = whitespace_rule(name_b);
1506        ecbdata.opt = o;
1507        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1508                mmfile_t mf1, mf2;
1509                mf1.ptr = (char *)data_one;
1510                mf2.ptr = (char *)data_two;
1511                mf1.size = size_one;
1512                mf2.size = size_two;
1513                check_blank_at_eof(&mf1, &mf2, &ecbdata);
1514        }
1515        ecbdata.lno_in_preimage = 1;
1516        ecbdata.lno_in_postimage = 1;
1517
1518        lc_a = count_lines(data_one, size_one);
1519        lc_b = count_lines(data_two, size_two);
1520
1521        emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1522                         a_name.buf, a_name.len, 0);
1523        emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1524                         b_name.buf, b_name.len, 0);
1525
1526        strbuf_addstr(&out, "@@ -");
1527        if (!o->irreversible_delete)
1528                add_line_count(&out, lc_a);
1529        else
1530                strbuf_addstr(&out, "?,?");
1531        strbuf_addstr(&out, " +");
1532        add_line_count(&out, lc_b);
1533        strbuf_addstr(&out, " @@\n");
1534        emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1535        strbuf_release(&out);
1536
1537        if (lc_a && !o->irreversible_delete)
1538                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1539        if (lc_b)
1540                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1541        if (textconv_one)
1542                free((char *)data_one);
1543        if (textconv_two)
1544                free((char *)data_two);
1545}
1546
1547struct diff_words_buffer {
1548        mmfile_t text;
1549        unsigned long alloc;
1550        struct diff_words_orig {
1551                const char *begin, *end;
1552        } *orig;
1553        int orig_nr, orig_alloc;
1554};
1555
1556static void diff_words_append(char *line, unsigned long len,
1557                struct diff_words_buffer *buffer)
1558{
1559        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1560        line++;
1561        len--;
1562        memcpy(buffer->text.ptr + buffer->text.size, line, len);
1563        buffer->text.size += len;
1564        buffer->text.ptr[buffer->text.size] = '\0';
1565}
1566
1567struct diff_words_style_elem {
1568        const char *prefix;
1569        const char *suffix;
1570        const char *color; /* NULL; filled in by the setup code if
1571                            * color is enabled */
1572};
1573
1574struct diff_words_style {
1575        enum diff_words_type type;
1576        struct diff_words_style_elem new, old, ctx;
1577        const char *newline;
1578};
1579
1580static struct diff_words_style diff_words_styles[] = {
1581        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1582        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1583        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1584};
1585
1586struct diff_words_data {
1587        struct diff_words_buffer minus, plus;
1588        const char *current_plus;
1589        int last_minus;
1590        struct diff_options *opt;
1591        regex_t *word_regex;
1592        enum diff_words_type type;
1593        struct diff_words_style *style;
1594};
1595
1596static int fn_out_diff_words_write_helper(struct diff_options *o,
1597                                          struct diff_words_style_elem *st_el,
1598                                          const char *newline,
1599                                          size_t count, const char *buf)
1600{
1601        int print = 0;
1602        struct strbuf sb = STRBUF_INIT;
1603
1604        while (count) {
1605                char *p = memchr(buf, '\n', count);
1606                if (print)
1607                        strbuf_addstr(&sb, diff_line_prefix(o));
1608
1609                if (p != buf) {
1610                        const char *reset = st_el->color && *st_el->color ?
1611                                            GIT_COLOR_RESET : NULL;
1612                        if (st_el->color && *st_el->color)
1613                                strbuf_addstr(&sb, st_el->color);
1614                        strbuf_addstr(&sb, st_el->prefix);
1615                        strbuf_add(&sb, buf, p ? p - buf : count);
1616                        strbuf_addstr(&sb, st_el->suffix);
1617                        if (reset)
1618                                strbuf_addstr(&sb, reset);
1619                }
1620                if (!p)
1621                        goto out;
1622
1623                strbuf_addstr(&sb, newline);
1624                count -= p + 1 - buf;
1625                buf = p + 1;
1626                print = 1;
1627                if (count) {
1628                        emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1629                                         sb.buf, sb.len, 0);
1630                        strbuf_reset(&sb);
1631                }
1632        }
1633
1634out:
1635        if (sb.len)
1636                emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1637                                 sb.buf, sb.len, 0);
1638        strbuf_release(&sb);
1639        return 0;
1640}
1641
1642/*
1643 * '--color-words' algorithm can be described as:
1644 *
1645 *   1. collect the minus/plus lines of a diff hunk, divided into
1646 *      minus-lines and plus-lines;
1647 *
1648 *   2. break both minus-lines and plus-lines into words and
1649 *      place them into two mmfile_t with one word for each line;
1650 *
1651 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1652 *
1653 * And for the common parts of the both file, we output the plus side text.
1654 * diff_words->current_plus is used to trace the current position of the plus file
1655 * which printed. diff_words->last_minus is used to trace the last minus word
1656 * printed.
1657 *
1658 * For '--graph' to work with '--color-words', we need to output the graph prefix
1659 * on each line of color words output. Generally, there are two conditions on
1660 * which we should output the prefix.
1661 *
1662 *   1. diff_words->last_minus == 0 &&
1663 *      diff_words->current_plus == diff_words->plus.text.ptr
1664 *
1665 *      that is: the plus text must start as a new line, and if there is no minus
1666 *      word printed, a graph prefix must be printed.
1667 *
1668 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1669 *      *(diff_words->current_plus - 1) == '\n'
1670 *
1671 *      that is: a graph prefix must be printed following a '\n'
1672 */
1673static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1674{
1675        if ((diff_words->last_minus == 0 &&
1676                diff_words->current_plus == diff_words->plus.text.ptr) ||
1677                (diff_words->current_plus > diff_words->plus.text.ptr &&
1678                *(diff_words->current_plus - 1) == '\n')) {
1679                return 1;
1680        } else {
1681                return 0;
1682        }
1683}
1684
1685static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1686{
1687        struct diff_words_data *diff_words = priv;
1688        struct diff_words_style *style = diff_words->style;
1689        int minus_first, minus_len, plus_first, plus_len;
1690        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1691        struct diff_options *opt = diff_words->opt;
1692        const char *line_prefix;
1693
1694        if (line[0] != '@' || parse_hunk_header(line, len,
1695                        &minus_first, &minus_len, &plus_first, &plus_len))
1696                return;
1697
1698        assert(opt);
1699        line_prefix = diff_line_prefix(opt);
1700
1701        /* POSIX requires that first be decremented by one if len == 0... */
1702        if (minus_len) {
1703                minus_begin = diff_words->minus.orig[minus_first].begin;
1704                minus_end =
1705                        diff_words->minus.orig[minus_first + minus_len - 1].end;
1706        } else
1707                minus_begin = minus_end =
1708                        diff_words->minus.orig[minus_first].end;
1709
1710        if (plus_len) {
1711                plus_begin = diff_words->plus.orig[plus_first].begin;
1712                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1713        } else
1714                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1715
1716        if (color_words_output_graph_prefix(diff_words)) {
1717                fputs(line_prefix, diff_words->opt->file);
1718        }
1719        if (diff_words->current_plus != plus_begin) {
1720                fn_out_diff_words_write_helper(diff_words->opt,
1721                                &style->ctx, style->newline,
1722                                plus_begin - diff_words->current_plus,
1723                                diff_words->current_plus);
1724        }
1725        if (minus_begin != minus_end) {
1726                fn_out_diff_words_write_helper(diff_words->opt,
1727                                &style->old, style->newline,
1728                                minus_end - minus_begin, minus_begin);
1729        }
1730        if (plus_begin != plus_end) {
1731                fn_out_diff_words_write_helper(diff_words->opt,
1732                                &style->new, style->newline,
1733                                plus_end - plus_begin, plus_begin);
1734        }
1735
1736        diff_words->current_plus = plus_end;
1737        diff_words->last_minus = minus_first;
1738}
1739
1740/* This function starts looking at *begin, and returns 0 iff a word was found. */
1741static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1742                int *begin, int *end)
1743{
1744        if (word_regex && *begin < buffer->size) {
1745                regmatch_t match[1];
1746                if (!regexec_buf(word_regex, buffer->ptr + *begin,
1747                                 buffer->size - *begin, 1, match, 0)) {
1748                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1749                                        '\n', match[0].rm_eo - match[0].rm_so);
1750                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1751                        *begin += match[0].rm_so;
1752                        return *begin >= *end;
1753                }
1754                return -1;
1755        }
1756
1757        /* find the next word */
1758        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1759                (*begin)++;
1760        if (*begin >= buffer->size)
1761                return -1;
1762
1763        /* find the end of the word */
1764        *end = *begin + 1;
1765        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1766                (*end)++;
1767
1768        return 0;
1769}
1770
1771/*
1772 * This function splits the words in buffer->text, stores the list with
1773 * newline separator into out, and saves the offsets of the original words
1774 * in buffer->orig.
1775 */
1776static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1777                regex_t *word_regex)
1778{
1779        int i, j;
1780        long alloc = 0;
1781
1782        out->size = 0;
1783        out->ptr = NULL;
1784
1785        /* fake an empty "0th" word */
1786        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1787        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1788        buffer->orig_nr = 1;
1789
1790        for (i = 0; i < buffer->text.size; i++) {
1791                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1792                        return;
1793
1794                /* store original boundaries */
1795                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1796                                buffer->orig_alloc);
1797                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1798                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1799                buffer->orig_nr++;
1800
1801                /* store one word */
1802                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1803                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1804                out->ptr[out->size + j - i] = '\n';
1805                out->size += j - i + 1;
1806
1807                i = j - 1;
1808        }
1809}
1810
1811/* this executes the word diff on the accumulated buffers */
1812static void diff_words_show(struct diff_words_data *diff_words)
1813{
1814        xpparam_t xpp;
1815        xdemitconf_t xecfg;
1816        mmfile_t minus, plus;
1817        struct diff_words_style *style = diff_words->style;
1818
1819        struct diff_options *opt = diff_words->opt;
1820        const char *line_prefix;
1821
1822        assert(opt);
1823        line_prefix = diff_line_prefix(opt);
1824
1825        /* special case: only removal */
1826        if (!diff_words->plus.text.size) {
1827                emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1828                                 line_prefix, strlen(line_prefix), 0);
1829                fn_out_diff_words_write_helper(diff_words->opt,
1830                        &style->old, style->newline,
1831                        diff_words->minus.text.size,
1832                        diff_words->minus.text.ptr);
1833                diff_words->minus.text.size = 0;
1834                return;
1835        }
1836
1837        diff_words->current_plus = diff_words->plus.text.ptr;
1838        diff_words->last_minus = 0;
1839
1840        memset(&xpp, 0, sizeof(xpp));
1841        memset(&xecfg, 0, sizeof(xecfg));
1842        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1843        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1844        xpp.flags = 0;
1845        /* as only the hunk header will be parsed, we need a 0-context */
1846        xecfg.ctxlen = 0;
1847        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1848                          &xpp, &xecfg))
1849                die("unable to generate word diff");
1850        free(minus.ptr);
1851        free(plus.ptr);
1852        if (diff_words->current_plus != diff_words->plus.text.ptr +
1853                        diff_words->plus.text.size) {
1854                if (color_words_output_graph_prefix(diff_words))
1855                        emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1856                                         line_prefix, strlen(line_prefix), 0);
1857                fn_out_diff_words_write_helper(diff_words->opt,
1858                        &style->ctx, style->newline,
1859                        diff_words->plus.text.ptr + diff_words->plus.text.size
1860                        - diff_words->current_plus, diff_words->current_plus);
1861        }
1862        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1863}
1864
1865/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1866static void diff_words_flush(struct emit_callback *ecbdata)
1867{
1868        struct diff_options *wo = ecbdata->diff_words->opt;
1869
1870        if (ecbdata->diff_words->minus.text.size ||
1871            ecbdata->diff_words->plus.text.size)
1872                diff_words_show(ecbdata->diff_words);
1873
1874        if (wo->emitted_symbols) {
1875                struct diff_options *o = ecbdata->opt;
1876                struct emitted_diff_symbols *wol = wo->emitted_symbols;
1877                int i;
1878
1879                /*
1880                 * NEEDSWORK:
1881                 * Instead of appending each, concat all words to a line?
1882                 */
1883                for (i = 0; i < wol->nr; i++)
1884                        append_emitted_diff_symbol(o, &wol->buf[i]);
1885
1886                for (i = 0; i < wol->nr; i++)
1887                        free((void *)wol->buf[i].line);
1888
1889                wol->nr = 0;
1890        }
1891}
1892
1893static void diff_filespec_load_driver(struct diff_filespec *one)
1894{
1895        /* Use already-loaded driver */
1896        if (one->driver)
1897                return;
1898
1899        if (S_ISREG(one->mode))
1900                one->driver = userdiff_find_by_path(one->path);
1901
1902        /* Fallback to default settings */
1903        if (!one->driver)
1904                one->driver = userdiff_find_by_name("default");
1905}
1906
1907static const char *userdiff_word_regex(struct diff_filespec *one)
1908{
1909        diff_filespec_load_driver(one);
1910        return one->driver->word_regex;
1911}
1912
1913static void init_diff_words_data(struct emit_callback *ecbdata,
1914                                 struct diff_options *orig_opts,
1915                                 struct diff_filespec *one,
1916                                 struct diff_filespec *two)
1917{
1918        int i;
1919        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1920        memcpy(o, orig_opts, sizeof(struct diff_options));
1921
1922        ecbdata->diff_words =
1923                xcalloc(1, sizeof(struct diff_words_data));
1924        ecbdata->diff_words->type = o->word_diff;
1925        ecbdata->diff_words->opt = o;
1926
1927        if (orig_opts->emitted_symbols)
1928                o->emitted_symbols =
1929                        xcalloc(1, sizeof(struct emitted_diff_symbols));
1930
1931        if (!o->word_regex)
1932                o->word_regex = userdiff_word_regex(one);
1933        if (!o->word_regex)
1934                o->word_regex = userdiff_word_regex(two);
1935        if (!o->word_regex)
1936                o->word_regex = diff_word_regex_cfg;
1937        if (o->word_regex) {
1938                ecbdata->diff_words->word_regex = (regex_t *)
1939                        xmalloc(sizeof(regex_t));
1940                if (regcomp(ecbdata->diff_words->word_regex,
1941                            o->word_regex,
1942                            REG_EXTENDED | REG_NEWLINE))
1943                        die ("Invalid regular expression: %s",
1944                             o->word_regex);
1945        }
1946        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1947                if (o->word_diff == diff_words_styles[i].type) {
1948                        ecbdata->diff_words->style =
1949                                &diff_words_styles[i];
1950                        break;
1951                }
1952        }
1953        if (want_color(o->use_color)) {
1954                struct diff_words_style *st = ecbdata->diff_words->style;
1955                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1956                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1957                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1958        }
1959}
1960
1961static void free_diff_words_data(struct emit_callback *ecbdata)
1962{
1963        if (ecbdata->diff_words) {
1964                diff_words_flush(ecbdata);
1965                free (ecbdata->diff_words->opt->emitted_symbols);
1966                free (ecbdata->diff_words->opt);
1967                free (ecbdata->diff_words->minus.text.ptr);
1968                free (ecbdata->diff_words->minus.orig);
1969                free (ecbdata->diff_words->plus.text.ptr);
1970                free (ecbdata->diff_words->plus.orig);
1971                if (ecbdata->diff_words->word_regex) {
1972                        regfree(ecbdata->diff_words->word_regex);
1973                        free(ecbdata->diff_words->word_regex);
1974                }
1975                FREE_AND_NULL(ecbdata->diff_words);
1976        }
1977}
1978
1979const char *diff_get_color(int diff_use_color, enum color_diff ix)
1980{
1981        if (want_color(diff_use_color))
1982                return diff_colors[ix];
1983        return "";
1984}
1985
1986const char *diff_line_prefix(struct diff_options *opt)
1987{
1988        struct strbuf *msgbuf;
1989        if (!opt->output_prefix)
1990                return "";
1991
1992        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1993        return msgbuf->buf;
1994}
1995
1996static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1997{
1998        const char *cp;
1999        unsigned long allot;
2000        size_t l = len;
2001
2002        cp = line;
2003        allot = l;
2004        while (0 < l) {
2005                (void) utf8_width(&cp, &l);
2006                if (!cp)
2007                        break; /* truncated in the middle? */
2008        }
2009        return allot - l;
2010}
2011
2012static void find_lno(const char *line, struct emit_callback *ecbdata)
2013{
2014        const char *p;
2015        ecbdata->lno_in_preimage = 0;
2016        ecbdata->lno_in_postimage = 0;
2017        p = strchr(line, '-');
2018        if (!p)
2019                return; /* cannot happen */
2020        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2021        p = strchr(p, '+');
2022        if (!p)
2023                return; /* cannot happen */
2024        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2025}
2026
2027static void fn_out_consume(void *priv, char *line, unsigned long len)
2028{
2029        struct emit_callback *ecbdata = priv;
2030        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
2031        struct diff_options *o = ecbdata->opt;
2032
2033        o->found_changes = 1;
2034
2035        if (ecbdata->header) {
2036                emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2037                                 ecbdata->header->buf, ecbdata->header->len, 0);
2038                strbuf_reset(ecbdata->header);
2039                ecbdata->header = NULL;
2040        }
2041
2042        if (ecbdata->label_path[0]) {
2043                emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2044                                 ecbdata->label_path[0],
2045                                 strlen(ecbdata->label_path[0]), 0);
2046                emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2047                                 ecbdata->label_path[1],
2048                                 strlen(ecbdata->label_path[1]), 0);
2049                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2050        }
2051
2052        if (diff_suppress_blank_empty
2053            && len == 2 && line[0] == ' ' && line[1] == '\n') {
2054                line[0] = '\n';
2055                len = 1;
2056        }
2057
2058        if (line[0] == '@') {
2059                if (ecbdata->diff_words)
2060                        diff_words_flush(ecbdata);
2061                len = sane_truncate_line(ecbdata, line, len);
2062                find_lno(line, ecbdata);
2063                emit_hunk_header(ecbdata, line, len);
2064                return;
2065        }
2066
2067        if (ecbdata->diff_words) {
2068                enum diff_symbol s =
2069                        ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2070                        DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2071                if (line[0] == '-') {
2072                        diff_words_append(line, len,
2073                                          &ecbdata->diff_words->minus);
2074                        return;
2075                } else if (line[0] == '+') {
2076                        diff_words_append(line, len,
2077                                          &ecbdata->diff_words->plus);
2078                        return;
2079                } else if (starts_with(line, "\\ ")) {
2080                        /*
2081                         * Eat the "no newline at eof" marker as if we
2082                         * saw a "+" or "-" line with nothing on it,
2083                         * and return without diff_words_flush() to
2084                         * defer processing. If this is the end of
2085                         * preimage, more "+" lines may come after it.
2086                         */
2087                        return;
2088                }
2089                diff_words_flush(ecbdata);
2090                emit_diff_symbol(o, s, line, len, 0);
2091                return;
2092        }
2093
2094        switch (line[0]) {
2095        case '+':
2096                ecbdata->lno_in_postimage++;
2097                emit_add_line(reset, ecbdata, line + 1, len - 1);
2098                break;
2099        case '-':
2100                ecbdata->lno_in_preimage++;
2101                emit_del_line(reset, ecbdata, line + 1, len - 1);
2102                break;
2103        case ' ':
2104                ecbdata->lno_in_postimage++;
2105                ecbdata->lno_in_preimage++;
2106                emit_context_line(reset, ecbdata, line + 1, len - 1);
2107                break;
2108        default:
2109                /* incomplete line at the end */
2110                ecbdata->lno_in_preimage++;
2111                emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2112                                 line, len, 0);
2113                break;
2114        }
2115}
2116
2117static char *pprint_rename(const char *a, const char *b)
2118{
2119        const char *old = a;
2120        const char *new = b;
2121        struct strbuf name = STRBUF_INIT;
2122        int pfx_length, sfx_length;
2123        int pfx_adjust_for_slash;
2124        int len_a = strlen(a);
2125        int len_b = strlen(b);
2126        int a_midlen, b_midlen;
2127        int qlen_a = quote_c_style(a, NULL, NULL, 0);
2128        int qlen_b = quote_c_style(b, NULL, NULL, 0);
2129
2130        if (qlen_a || qlen_b) {
2131                quote_c_style(a, &name, NULL, 0);
2132                strbuf_addstr(&name, " => ");
2133                quote_c_style(b, &name, NULL, 0);
2134                return strbuf_detach(&name, NULL);
2135        }
2136
2137        /* Find common prefix */
2138        pfx_length = 0;
2139        while (*old && *new && *old == *new) {
2140                if (*old == '/')
2141                        pfx_length = old - a + 1;
2142                old++;
2143                new++;
2144        }
2145
2146        /* Find common suffix */
2147        old = a + len_a;
2148        new = b + len_b;
2149        sfx_length = 0;
2150        /*
2151         * If there is a common prefix, it must end in a slash.  In
2152         * that case we let this loop run 1 into the prefix to see the
2153         * same slash.
2154         *
2155         * If there is no common prefix, we cannot do this as it would
2156         * underrun the input strings.
2157         */
2158        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2159        while (a + pfx_length - pfx_adjust_for_slash <= old &&
2160               b + pfx_length - pfx_adjust_for_slash <= new &&
2161               *old == *new) {
2162                if (*old == '/')
2163                        sfx_length = len_a - (old - a);
2164                old--;
2165                new--;
2166        }
2167
2168        /*
2169         * pfx{mid-a => mid-b}sfx
2170         * {pfx-a => pfx-b}sfx
2171         * pfx{sfx-a => sfx-b}
2172         * name-a => name-b
2173         */
2174        a_midlen = len_a - pfx_length - sfx_length;
2175        b_midlen = len_b - pfx_length - sfx_length;
2176        if (a_midlen < 0)
2177                a_midlen = 0;
2178        if (b_midlen < 0)
2179                b_midlen = 0;
2180
2181        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2182        if (pfx_length + sfx_length) {
2183                strbuf_add(&name, a, pfx_length);
2184                strbuf_addch(&name, '{');
2185        }
2186        strbuf_add(&name, a + pfx_length, a_midlen);
2187        strbuf_addstr(&name, " => ");
2188        strbuf_add(&name, b + pfx_length, b_midlen);
2189        if (pfx_length + sfx_length) {
2190                strbuf_addch(&name, '}');
2191                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
2192        }
2193        return strbuf_detach(&name, NULL);
2194}
2195
2196struct diffstat_t {
2197        int nr;
2198        int alloc;
2199        struct diffstat_file {
2200                char *from_name;
2201                char *name;
2202                char *print_name;
2203                unsigned is_unmerged:1;
2204                unsigned is_binary:1;
2205                unsigned is_renamed:1;
2206                unsigned is_interesting:1;
2207                uintmax_t added, deleted;
2208        } **files;
2209};
2210
2211static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2212                                          const char *name_a,
2213                                          const char *name_b)
2214{
2215        struct diffstat_file *x;
2216        x = xcalloc(1, sizeof(*x));
2217        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2218        diffstat->files[diffstat->nr++] = x;
2219        if (name_b) {
2220                x->from_name = xstrdup(name_a);
2221                x->name = xstrdup(name_b);
2222                x->is_renamed = 1;
2223        }
2224        else {
2225                x->from_name = NULL;
2226                x->name = xstrdup(name_a);
2227        }
2228        return x;
2229}
2230
2231static void diffstat_consume(void *priv, char *line, unsigned long len)
2232{
2233        struct diffstat_t *diffstat = priv;
2234        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2235
2236        if (line[0] == '+')
2237                x->added++;
2238        else if (line[0] == '-')
2239                x->deleted++;
2240}
2241
2242const char mime_boundary_leader[] = "------------";
2243
2244static int scale_linear(int it, int width, int max_change)
2245{
2246        if (!it)
2247                return 0;
2248        /*
2249         * make sure that at least one '-' or '+' is printed if
2250         * there is any change to this path. The easiest way is to
2251         * scale linearly as if the alloted width is one column shorter
2252         * than it is, and then add 1 to the result.
2253         */
2254        return 1 + (it * (width - 1) / max_change);
2255}
2256
2257static void show_graph(struct strbuf *out, char ch, int cnt,
2258                       const char *set, const char *reset)
2259{
2260        if (cnt <= 0)
2261                return;
2262        strbuf_addstr(out, set);
2263        strbuf_addchars(out, ch, cnt);
2264        strbuf_addstr(out, reset);
2265}
2266
2267static void fill_print_name(struct diffstat_file *file)
2268{
2269        char *pname;
2270
2271        if (file->print_name)
2272                return;
2273
2274        if (!file->is_renamed) {
2275                struct strbuf buf = STRBUF_INIT;
2276                if (quote_c_style(file->name, &buf, NULL, 0)) {
2277                        pname = strbuf_detach(&buf, NULL);
2278                } else {
2279                        pname = file->name;
2280                        strbuf_release(&buf);
2281                }
2282        } else {
2283                pname = pprint_rename(file->from_name, file->name);
2284        }
2285        file->print_name = pname;
2286}
2287
2288static void print_stat_summary_inserts_deletes(struct diff_options *options,
2289                int files, int insertions, int deletions)
2290{
2291        struct strbuf sb = STRBUF_INIT;
2292
2293        if (!files) {
2294                assert(insertions == 0 && deletions == 0);
2295                emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2296                                 NULL, 0, 0);
2297                return;
2298        }
2299
2300        strbuf_addf(&sb,
2301                    (files == 1) ? " %d file changed" : " %d files changed",
2302                    files);
2303
2304        /*
2305         * For binary diff, the caller may want to print "x files
2306         * changed" with insertions == 0 && deletions == 0.
2307         *
2308         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2309         * is probably less confusing (i.e skip over "2 files changed
2310         * but nothing about added/removed lines? Is this a bug in Git?").
2311         */
2312        if (insertions || deletions == 0) {
2313                strbuf_addf(&sb,
2314                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2315                            insertions);
2316        }
2317
2318        if (deletions || insertions == 0) {
2319                strbuf_addf(&sb,
2320                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2321                            deletions);
2322        }
2323        strbuf_addch(&sb, '\n');
2324        emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2325                         sb.buf, sb.len, 0);
2326        strbuf_release(&sb);
2327}
2328
2329void print_stat_summary(FILE *fp, int files,
2330                        int insertions, int deletions)
2331{
2332        struct diff_options o;
2333        memset(&o, 0, sizeof(o));
2334        o.file = fp;
2335
2336        print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2337}
2338
2339static void show_stats(struct diffstat_t *data, struct diff_options *options)
2340{
2341        int i, len, add, del, adds = 0, dels = 0;
2342        uintmax_t max_change = 0, max_len = 0;
2343        int total_files = data->nr, count;
2344        int width, name_width, graph_width, number_width = 0, bin_width = 0;
2345        const char *reset, *add_c, *del_c;
2346        int extra_shown = 0;
2347        const char *line_prefix = diff_line_prefix(options);
2348        struct strbuf out = STRBUF_INIT;
2349
2350        if (data->nr == 0)
2351                return;
2352
2353        count = options->stat_count ? options->stat_count : data->nr;
2354
2355        reset = diff_get_color_opt(options, DIFF_RESET);
2356        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2357        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2358
2359        /*
2360         * Find the longest filename and max number of changes
2361         */
2362        for (i = 0; (i < count) && (i < data->nr); i++) {
2363                struct diffstat_file *file = data->files[i];
2364                uintmax_t change = file->added + file->deleted;
2365
2366                if (!file->is_interesting && (change == 0)) {
2367                        count++; /* not shown == room for one more */
2368                        continue;
2369                }
2370                fill_print_name(file);
2371                len = strlen(file->print_name);
2372                if (max_len < len)
2373                        max_len = len;
2374
2375                if (file->is_unmerged) {
2376                        /* "Unmerged" is 8 characters */
2377                        bin_width = bin_width < 8 ? 8 : bin_width;
2378                        continue;
2379                }
2380                if (file->is_binary) {
2381                        /* "Bin XXX -> YYY bytes" */
2382                        int w = 14 + decimal_width(file->added)
2383                                + decimal_width(file->deleted);
2384                        bin_width = bin_width < w ? w : bin_width;
2385                        /* Display change counts aligned with "Bin" */
2386                        number_width = 3;
2387                        continue;
2388                }
2389
2390                if (max_change < change)
2391                        max_change = change;
2392        }
2393        count = i; /* where we can stop scanning in data->files[] */
2394
2395        /*
2396         * We have width = stat_width or term_columns() columns total.
2397         * We want a maximum of min(max_len, stat_name_width) for the name part.
2398         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2399         * We also need 1 for " " and 4 + decimal_width(max_change)
2400         * for " | NNNN " and one the empty column at the end, altogether
2401         * 6 + decimal_width(max_change).
2402         *
2403         * If there's not enough space, we will use the smaller of
2404         * stat_name_width (if set) and 5/8*width for the filename,
2405         * and the rest for constant elements + graph part, but no more
2406         * than stat_graph_width for the graph part.
2407         * (5/8 gives 50 for filename and 30 for the constant parts + graph
2408         * for the standard terminal size).
2409         *
2410         * In other words: stat_width limits the maximum width, and
2411         * stat_name_width fixes the maximum width of the filename,
2412         * and is also used to divide available columns if there
2413         * aren't enough.
2414         *
2415         * Binary files are displayed with "Bin XXX -> YYY bytes"
2416         * instead of the change count and graph. This part is treated
2417         * similarly to the graph part, except that it is not
2418         * "scaled". If total width is too small to accommodate the
2419         * guaranteed minimum width of the filename part and the
2420         * separators and this message, this message will "overflow"
2421         * making the line longer than the maximum width.
2422         */
2423
2424        if (options->stat_width == -1)
2425                width = term_columns() - strlen(line_prefix);
2426        else
2427                width = options->stat_width ? options->stat_width : 80;
2428        number_width = decimal_width(max_change) > number_width ?
2429                decimal_width(max_change) : number_width;
2430
2431        if (options->stat_graph_width == -1)
2432                options->stat_graph_width = diff_stat_graph_width;
2433
2434        /*
2435         * Guarantee 3/8*16==6 for the graph part
2436         * and 5/8*16==10 for the filename part
2437         */
2438        if (width < 16 + 6 + number_width)
2439                width = 16 + 6 + number_width;
2440
2441        /*
2442         * First assign sizes that are wanted, ignoring available width.
2443         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2444         * starting from "XXX" should fit in graph_width.
2445         */
2446        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2447        if (options->stat_graph_width &&
2448            options->stat_graph_width < graph_width)
2449                graph_width = options->stat_graph_width;
2450
2451        name_width = (options->stat_name_width > 0 &&
2452                      options->stat_name_width < max_len) ?
2453                options->stat_name_width : max_len;
2454
2455        /*
2456         * Adjust adjustable widths not to exceed maximum width
2457         */
2458        if (name_width + number_width + 6 + graph_width > width) {
2459                if (graph_width > width * 3/8 - number_width - 6) {
2460                        graph_width = width * 3/8 - number_width - 6;
2461                        if (graph_width < 6)
2462                                graph_width = 6;
2463                }
2464
2465                if (options->stat_graph_width &&
2466                    graph_width > options->stat_graph_width)
2467                        graph_width = options->stat_graph_width;
2468                if (name_width > width - number_width - 6 - graph_width)
2469                        name_width = width - number_width - 6 - graph_width;
2470                else
2471                        graph_width = width - number_width - 6 - name_width;
2472        }
2473
2474        /*
2475         * From here name_width is the width of the name area,
2476         * and graph_width is the width of the graph area.
2477         * max_change is used to scale graph properly.
2478         */
2479        for (i = 0; i < count; i++) {
2480                const char *prefix = "";
2481                struct diffstat_file *file = data->files[i];
2482                char *name = file->print_name;
2483                uintmax_t added = file->added;
2484                uintmax_t deleted = file->deleted;
2485                int name_len;
2486
2487                if (!file->is_interesting && (added + deleted == 0))
2488                        continue;
2489
2490                /*
2491                 * "scale" the filename
2492                 */
2493                len = name_width;
2494                name_len = strlen(name);
2495                if (name_width < name_len) {
2496                        char *slash;
2497                        prefix = "...";
2498                        len -= 3;
2499                        name += name_len - len;
2500                        slash = strchr(name, '/');
2501                        if (slash)
2502                                name = slash;
2503                }
2504
2505                if (file->is_binary) {
2506                        strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2507                        strbuf_addf(&out, " %*s", number_width, "Bin");
2508                        if (!added && !deleted) {
2509                                strbuf_addch(&out, '\n');
2510                                emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2511                                                 out.buf, out.len, 0);
2512                                strbuf_reset(&out);
2513                                continue;
2514                        }
2515                        strbuf_addf(&out, " %s%"PRIuMAX"%s",
2516                                del_c, deleted, reset);
2517                        strbuf_addstr(&out, " -> ");
2518                        strbuf_addf(&out, "%s%"PRIuMAX"%s",
2519                                add_c, added, reset);
2520                        strbuf_addstr(&out, " bytes\n");
2521                        emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2522                                         out.buf, out.len, 0);
2523                        strbuf_reset(&out);
2524                        continue;
2525                }
2526                else if (file->is_unmerged) {
2527                        strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2528                        strbuf_addstr(&out, " Unmerged\n");
2529                        emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2530                                         out.buf, out.len, 0);
2531                        strbuf_reset(&out);
2532                        continue;
2533                }
2534
2535                /*
2536                 * scale the add/delete
2537                 */
2538                add = added;
2539                del = deleted;
2540
2541                if (graph_width <= max_change) {
2542                        int total = scale_linear(add + del, graph_width, max_change);
2543                        if (total < 2 && add && del)
2544                                /* width >= 2 due to the sanity check */
2545                                total = 2;
2546                        if (add < del) {
2547                                add = scale_linear(add, graph_width, max_change);
2548                                del = total - add;
2549                        } else {
2550                                del = scale_linear(del, graph_width, max_change);
2551                                add = total - del;
2552                        }
2553                }
2554                strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2555                strbuf_addf(&out, " %*"PRIuMAX"%s",
2556                        number_width, added + deleted,
2557                        added + deleted ? " " : "");
2558                show_graph(&out, '+', add, add_c, reset);
2559                show_graph(&out, '-', del, del_c, reset);
2560                strbuf_addch(&out, '\n');
2561                emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2562                                 out.buf, out.len, 0);
2563                strbuf_reset(&out);
2564        }
2565
2566        for (i = 0; i < data->nr; i++) {
2567                struct diffstat_file *file = data->files[i];
2568                uintmax_t added = file->added;
2569                uintmax_t deleted = file->deleted;
2570
2571                if (file->is_unmerged ||
2572                    (!file->is_interesting && (added + deleted == 0))) {
2573                        total_files--;
2574                        continue;
2575                }
2576
2577                if (!file->is_binary) {
2578                        adds += added;
2579                        dels += deleted;
2580                }
2581                if (i < count)
2582                        continue;
2583                if (!extra_shown)
2584                        emit_diff_symbol(options,
2585                                         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2586                                         NULL, 0, 0);
2587                extra_shown = 1;
2588        }
2589
2590        print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2591        strbuf_release(&out);
2592}
2593
2594static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2595{
2596        int i, adds = 0, dels = 0, total_files = data->nr;
2597
2598        if (data->nr == 0)
2599                return;
2600
2601        for (i = 0; i < data->nr; i++) {
2602                int added = data->files[i]->added;
2603                int deleted = data->files[i]->deleted;
2604
2605                if (data->files[i]->is_unmerged ||
2606                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
2607                        total_files--;
2608                } else if (!data->files[i]->is_binary) { /* don't count bytes */
2609                        adds += added;
2610                        dels += deleted;
2611                }
2612        }
2613        print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2614}
2615
2616static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2617{
2618        int i;
2619
2620        if (data->nr == 0)
2621                return;
2622
2623        for (i = 0; i < data->nr; i++) {
2624                struct diffstat_file *file = data->files[i];
2625
2626                fprintf(options->file, "%s", diff_line_prefix(options));
2627
2628                if (file->is_binary)
2629                        fprintf(options->file, "-\t-\t");
2630                else
2631                        fprintf(options->file,
2632                                "%"PRIuMAX"\t%"PRIuMAX"\t",
2633                                file->added, file->deleted);
2634                if (options->line_termination) {
2635                        fill_print_name(file);
2636                        if (!file->is_renamed)
2637                                write_name_quoted(file->name, options->file,
2638                                                  options->line_termination);
2639                        else {
2640                                fputs(file->print_name, options->file);
2641                                putc(options->line_termination, options->file);
2642                        }
2643                } else {
2644                        if (file->is_renamed) {
2645                                putc('\0', options->file);
2646                                write_name_quoted(file->from_name, options->file, '\0');
2647                        }
2648                        write_name_quoted(file->name, options->file, '\0');
2649                }
2650        }
2651}
2652
2653struct dirstat_file {
2654        const char *name;
2655        unsigned long changed;
2656};
2657
2658struct dirstat_dir {
2659        struct dirstat_file *files;
2660        int alloc, nr, permille, cumulative;
2661};
2662
2663static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2664                unsigned long changed, const char *base, int baselen)
2665{
2666        unsigned long this_dir = 0;
2667        unsigned int sources = 0;
2668        const char *line_prefix = diff_line_prefix(opt);
2669
2670        while (dir->nr) {
2671                struct dirstat_file *f = dir->files;
2672                int namelen = strlen(f->name);
2673                unsigned long this;
2674                char *slash;
2675
2676                if (namelen < baselen)
2677                        break;
2678                if (memcmp(f->name, base, baselen))
2679                        break;
2680                slash = strchr(f->name + baselen, '/');
2681                if (slash) {
2682                        int newbaselen = slash + 1 - f->name;
2683                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2684                        sources++;
2685                } else {
2686                        this = f->changed;
2687                        dir->files++;
2688                        dir->nr--;
2689                        sources += 2;
2690                }
2691                this_dir += this;
2692        }
2693
2694        /*
2695         * We don't report dirstat's for
2696         *  - the top level
2697         *  - or cases where everything came from a single directory
2698         *    under this directory (sources == 1).
2699         */
2700        if (baselen && sources != 1) {
2701                if (this_dir) {
2702                        int permille = this_dir * 1000 / changed;
2703                        if (permille >= dir->permille) {
2704                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2705                                        permille / 10, permille % 10, baselen, base);
2706                                if (!dir->cumulative)
2707                                        return 0;
2708                        }
2709                }
2710        }
2711        return this_dir;
2712}
2713
2714static int dirstat_compare(const void *_a, const void *_b)
2715{
2716        const struct dirstat_file *a = _a;
2717        const struct dirstat_file *b = _b;
2718        return strcmp(a->name, b->name);
2719}
2720
2721static void show_dirstat(struct diff_options *options)
2722{
2723        int i;
2724        unsigned long changed;
2725        struct dirstat_dir dir;
2726        struct diff_queue_struct *q = &diff_queued_diff;
2727
2728        dir.files = NULL;
2729        dir.alloc = 0;
2730        dir.nr = 0;
2731        dir.permille = options->dirstat_permille;
2732        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2733
2734        changed = 0;
2735        for (i = 0; i < q->nr; i++) {
2736                struct diff_filepair *p = q->queue[i];
2737                const char *name;
2738                unsigned long copied, added, damage;
2739                int content_changed;
2740
2741                name = p->two->path ? p->two->path : p->one->path;
2742
2743                if (p->one->oid_valid && p->two->oid_valid)
2744                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
2745                else
2746                        content_changed = 1;
2747
2748                if (!content_changed) {
2749                        /*
2750                         * The SHA1 has not changed, so pre-/post-content is
2751                         * identical. We can therefore skip looking at the
2752                         * file contents altogether.
2753                         */
2754                        damage = 0;
2755                        goto found_damage;
2756                }
2757
2758                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2759                        /*
2760                         * In --dirstat-by-file mode, we don't really need to
2761                         * look at the actual file contents at all.
2762                         * The fact that the SHA1 changed is enough for us to
2763                         * add this file to the list of results
2764                         * (with each file contributing equal damage).
2765                         */
2766                        damage = 1;
2767                        goto found_damage;
2768                }
2769
2770                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2771                        diff_populate_filespec(p->one, 0);
2772                        diff_populate_filespec(p->two, 0);
2773                        diffcore_count_changes(p->one, p->two, NULL, NULL,
2774                                               &copied, &added);
2775                        diff_free_filespec_data(p->one);
2776                        diff_free_filespec_data(p->two);
2777                } else if (DIFF_FILE_VALID(p->one)) {
2778                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2779                        copied = added = 0;
2780                        diff_free_filespec_data(p->one);
2781                } else if (DIFF_FILE_VALID(p->two)) {
2782                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2783                        copied = 0;
2784                        added = p->two->size;
2785                        diff_free_filespec_data(p->two);
2786                } else
2787                        continue;
2788
2789                /*
2790                 * Original minus copied is the removed material,
2791                 * added is the new material.  They are both damages
2792                 * made to the preimage.
2793                 * If the resulting damage is zero, we know that
2794                 * diffcore_count_changes() considers the two entries to
2795                 * be identical, but since content_changed is true, we
2796                 * know that there must have been _some_ kind of change,
2797                 * so we force all entries to have damage > 0.
2798                 */
2799                damage = (p->one->size - copied) + added;
2800                if (!damage)
2801                        damage = 1;
2802
2803found_damage:
2804                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2805                dir.files[dir.nr].name = name;
2806                dir.files[dir.nr].changed = damage;
2807                changed += damage;
2808                dir.nr++;
2809        }
2810
2811        /* This can happen even with many files, if everything was renames */
2812        if (!changed)
2813                return;
2814
2815        /* Show all directories with more than x% of the changes */
2816        QSORT(dir.files, dir.nr, dirstat_compare);
2817        gather_dirstat(options, &dir, changed, "", 0);
2818}
2819
2820static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2821{
2822        int i;
2823        unsigned long changed;
2824        struct dirstat_dir dir;
2825
2826        if (data->nr == 0)
2827                return;
2828
2829        dir.files = NULL;
2830        dir.alloc = 0;
2831        dir.nr = 0;
2832        dir.permille = options->dirstat_permille;
2833        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2834
2835        changed = 0;
2836        for (i = 0; i < data->nr; i++) {
2837                struct diffstat_file *file = data->files[i];
2838                unsigned long damage = file->added + file->deleted;
2839                if (file->is_binary)
2840                        /*
2841                         * binary files counts bytes, not lines. Must find some
2842                         * way to normalize binary bytes vs. textual lines.
2843                         * The following heuristic assumes that there are 64
2844                         * bytes per "line".
2845                         * This is stupid and ugly, but very cheap...
2846                         */
2847                        damage = DIV_ROUND_UP(damage, 64);
2848                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2849                dir.files[dir.nr].name = file->name;
2850                dir.files[dir.nr].changed = damage;
2851                changed += damage;
2852                dir.nr++;
2853        }
2854
2855        /* This can happen even with many files, if everything was renames */
2856        if (!changed)
2857                return;
2858
2859        /* Show all directories with more than x% of the changes */
2860        QSORT(dir.files, dir.nr, dirstat_compare);
2861        gather_dirstat(options, &dir, changed, "", 0);
2862}
2863
2864static void free_diffstat_info(struct diffstat_t *diffstat)
2865{
2866        int i;
2867        for (i = 0; i < diffstat->nr; i++) {
2868                struct diffstat_file *f = diffstat->files[i];
2869                if (f->name != f->print_name)
2870                        free(f->print_name);
2871                free(f->name);
2872                free(f->from_name);
2873                free(f);
2874        }
2875        free(diffstat->files);
2876}
2877
2878struct checkdiff_t {
2879        const char *filename;
2880        int lineno;
2881        int conflict_marker_size;
2882        struct diff_options *o;
2883        unsigned ws_rule;
2884        unsigned status;
2885};
2886
2887static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2888{
2889        char firstchar;
2890        int cnt;
2891
2892        if (len < marker_size + 1)
2893                return 0;
2894        firstchar = line[0];
2895        switch (firstchar) {
2896        case '=': case '>': case '<': case '|':
2897                break;
2898        default:
2899                return 0;
2900        }
2901        for (cnt = 1; cnt < marker_size; cnt++)
2902                if (line[cnt] != firstchar)
2903                        return 0;
2904        /* line[1] thru line[marker_size-1] are same as firstchar */
2905        if (len < marker_size + 1 || !isspace(line[marker_size]))
2906                return 0;
2907        return 1;
2908}
2909
2910static void checkdiff_consume(void *priv, char *line, unsigned long len)
2911{
2912        struct checkdiff_t *data = priv;
2913        int marker_size = data->conflict_marker_size;
2914        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2915        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2916        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2917        char *err;
2918        const char *line_prefix;
2919
2920        assert(data->o);
2921        line_prefix = diff_line_prefix(data->o);
2922
2923        if (line[0] == '+') {
2924                unsigned bad;
2925                data->lineno++;
2926                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2927                        data->status |= 1;
2928                        fprintf(data->o->file,
2929                                "%s%s:%d: leftover conflict marker\n",
2930                                line_prefix, data->filename, data->lineno);
2931                }
2932                bad = ws_check(line + 1, len - 1, data->ws_rule);
2933                if (!bad)
2934                        return;
2935                data->status |= bad;
2936                err = whitespace_error_string(bad);
2937                fprintf(data->o->file, "%s%s:%d: %s.\n",
2938                        line_prefix, data->filename, data->lineno, err);
2939                free(err);
2940                emit_line(data->o, set, reset, line, 1);
2941                ws_check_emit(line + 1, len - 1, data->ws_rule,
2942                              data->o->file, set, reset, ws);
2943        } else if (line[0] == ' ') {
2944                data->lineno++;
2945        } else if (line[0] == '@') {
2946                char *plus = strchr(line, '+');
2947                if (plus)
2948                        data->lineno = strtol(plus, NULL, 10) - 1;
2949                else
2950                        die("invalid diff");
2951        }
2952}
2953
2954static unsigned char *deflate_it(char *data,
2955                                 unsigned long size,
2956                                 unsigned long *result_size)
2957{
2958        int bound;
2959        unsigned char *deflated;
2960        git_zstream stream;
2961
2962        git_deflate_init(&stream, zlib_compression_level);
2963        bound = git_deflate_bound(&stream, size);
2964        deflated = xmalloc(bound);
2965        stream.next_out = deflated;
2966        stream.avail_out = bound;
2967
2968        stream.next_in = (unsigned char *)data;
2969        stream.avail_in = size;
2970        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2971                ; /* nothing */
2972        git_deflate_end(&stream);
2973        *result_size = stream.total_out;
2974        return deflated;
2975}
2976
2977static void emit_binary_diff_body(struct diff_options *o,
2978                                  mmfile_t *one, mmfile_t *two)
2979{
2980        void *cp;
2981        void *delta;
2982        void *deflated;
2983        void *data;
2984        unsigned long orig_size;
2985        unsigned long delta_size;
2986        unsigned long deflate_size;
2987        unsigned long data_size;
2988
2989        /* We could do deflated delta, or we could do just deflated two,
2990         * whichever is smaller.
2991         */
2992        delta = NULL;
2993        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2994        if (one->size && two->size) {
2995                delta = diff_delta(one->ptr, one->size,
2996                                   two->ptr, two->size,
2997                                   &delta_size, deflate_size);
2998                if (delta) {
2999                        void *to_free = delta;
3000                        orig_size = delta_size;
3001                        delta = deflate_it(delta, delta_size, &delta_size);
3002                        free(to_free);
3003                }
3004        }
3005
3006        if (delta && delta_size < deflate_size) {
3007                char *s = xstrfmt("%lu", orig_size);
3008                emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3009                                 s, strlen(s), 0);
3010                free(s);
3011                free(deflated);
3012                data = delta;
3013                data_size = delta_size;
3014        } else {
3015                char *s = xstrfmt("%lu", two->size);
3016                emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3017                                 s, strlen(s), 0);
3018                free(s);
3019                free(delta);
3020                data = deflated;
3021                data_size = deflate_size;
3022        }
3023
3024        /* emit data encoded in base85 */
3025        cp = data;
3026        while (data_size) {
3027                int len;
3028                int bytes = (52 < data_size) ? 52 : data_size;
3029                char line[71];
3030                data_size -= bytes;
3031                if (bytes <= 26)
3032                        line[0] = bytes + 'A' - 1;
3033                else
3034                        line[0] = bytes - 26 + 'a' - 1;
3035                encode_85(line + 1, cp, bytes);
3036                cp = (char *) cp + bytes;
3037
3038                len = strlen(line);
3039                line[len++] = '\n';
3040                line[len] = '\0';
3041
3042                emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3043                                 line, len, 0);
3044        }
3045        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3046        free(data);
3047}
3048
3049static void emit_binary_diff(struct diff_options *o,
3050                             mmfile_t *one, mmfile_t *two)
3051{
3052        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3053        emit_binary_diff_body(o, one, two);
3054        emit_binary_diff_body(o, two, one);
3055}
3056
3057int diff_filespec_is_binary(struct diff_filespec *one)
3058{
3059        if (one->is_binary == -1) {
3060                diff_filespec_load_driver(one);
3061                if (one->driver->binary != -1)
3062                        one->is_binary = one->driver->binary;
3063                else {
3064                        if (!one->data && DIFF_FILE_VALID(one))
3065                                diff_populate_filespec(one, CHECK_BINARY);
3066                        if (one->is_binary == -1 && one->data)
3067                                one->is_binary = buffer_is_binary(one->data,
3068                                                one->size);
3069                        if (one->is_binary == -1)
3070                                one->is_binary = 0;
3071                }
3072        }
3073        return one->is_binary;
3074}
3075
3076static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
3077{
3078        diff_filespec_load_driver(one);
3079        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3080}
3081
3082void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3083{
3084        if (!options->a_prefix)
3085                options->a_prefix = a;
3086        if (!options->b_prefix)
3087                options->b_prefix = b;
3088}
3089
3090struct userdiff_driver *get_textconv(struct diff_filespec *one)
3091{
3092        if (!DIFF_FILE_VALID(one))
3093                return NULL;
3094
3095        diff_filespec_load_driver(one);
3096        return userdiff_get_textconv(one->driver);
3097}
3098
3099static void builtin_diff(const char *name_a,
3100                         const char *name_b,
3101                         struct diff_filespec *one,
3102                         struct diff_filespec *two,
3103                         const char *xfrm_msg,
3104                         int must_show_header,
3105                         struct diff_options *o,
3106                         int complete_rewrite)
3107{
3108        mmfile_t mf1, mf2;
3109        const char *lbl[2];
3110        char *a_one, *b_two;
3111        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3112        const char *reset = diff_get_color_opt(o, DIFF_RESET);
3113        const char *a_prefix, *b_prefix;
3114        struct userdiff_driver *textconv_one = NULL;
3115        struct userdiff_driver *textconv_two = NULL;
3116        struct strbuf header = STRBUF_INIT;
3117        const char *line_prefix = diff_line_prefix(o);
3118
3119        diff_set_mnemonic_prefix(o, "a/", "b/");
3120        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
3121                a_prefix = o->b_prefix;
3122                b_prefix = o->a_prefix;
3123        } else {
3124                a_prefix = o->a_prefix;
3125                b_prefix = o->b_prefix;
3126        }
3127
3128        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3129            (!one->mode || S_ISGITLINK(one->mode)) &&
3130            (!two->mode || S_ISGITLINK(two->mode))) {
3131                show_submodule_summary(o, one->path ? one->path : two->path,
3132                                &one->oid, &two->oid,
3133                                two->dirty_submodule);
3134                return;
3135        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3136                   (!one->mode || S_ISGITLINK(one->mode)) &&
3137                   (!two->mode || S_ISGITLINK(two->mode))) {
3138                show_submodule_inline_diff(o, one->path ? one->path : two->path,
3139                                &one->oid, &two->oid,
3140                                two->dirty_submodule);
3141                return;
3142        }
3143
3144        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
3145                textconv_one = get_textconv(one);
3146                textconv_two = get_textconv(two);
3147        }
3148
3149        /* Never use a non-valid filename anywhere if at all possible */
3150        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3151        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3152
3153        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3154        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3155        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3156        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3157        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3158        if (lbl[0][0] == '/') {
3159                /* /dev/null */
3160                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3161                if (xfrm_msg)
3162                        strbuf_addstr(&header, xfrm_msg);
3163                must_show_header = 1;
3164        }
3165        else if (lbl[1][0] == '/') {
3166                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3167                if (xfrm_msg)
3168                        strbuf_addstr(&header, xfrm_msg);
3169                must_show_header = 1;
3170        }
3171        else {
3172                if (one->mode != two->mode) {
3173                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3174                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3175                        must_show_header = 1;
3176                }
3177                if (xfrm_msg)
3178                        strbuf_addstr(&header, xfrm_msg);
3179
3180                /*
3181                 * we do not run diff between different kind
3182                 * of objects.
3183                 */
3184                if ((one->mode ^ two->mode) & S_IFMT)
3185                        goto free_ab_and_return;
3186                if (complete_rewrite &&
3187                    (textconv_one || !diff_filespec_is_binary(one)) &&
3188                    (textconv_two || !diff_filespec_is_binary(two))) {
3189                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3190                                         header.buf, header.len, 0);
3191                        strbuf_reset(&header);
3192                        emit_rewrite_diff(name_a, name_b, one, two,
3193                                                textconv_one, textconv_two, o);
3194                        o->found_changes = 1;
3195                        goto free_ab_and_return;
3196                }
3197        }
3198
3199        if (o->irreversible_delete && lbl[1][0] == '/') {
3200                emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3201                                 header.len, 0);
3202                strbuf_reset(&header);
3203                goto free_ab_and_return;
3204        } else if (!DIFF_OPT_TST(o, TEXT) &&
3205            ( (!textconv_one && diff_filespec_is_binary(one)) ||
3206              (!textconv_two && diff_filespec_is_binary(two)) )) {
3207                struct strbuf sb = STRBUF_INIT;
3208                if (!one->data && !two->data &&
3209                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
3210                    !DIFF_OPT_TST(o, BINARY)) {
3211                        if (!oidcmp(&one->oid, &two->oid)) {
3212                                if (must_show_header)
3213                                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3214                                                         header.buf, header.len,
3215                                                         0);
3216                                goto free_ab_and_return;
3217                        }
3218                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3219                                         header.buf, header.len, 0);
3220                        strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3221                                    diff_line_prefix(o), lbl[0], lbl[1]);
3222                        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3223                                         sb.buf, sb.len, 0);
3224                        strbuf_release(&sb);
3225                        goto free_ab_and_return;
3226                }
3227                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3228                        die("unable to read files to diff");
3229                /* Quite common confusing case */
3230                if (mf1.size == mf2.size &&
3231                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3232                        if (must_show_header)
3233                                emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3234                                                 header.buf, header.len, 0);
3235                        goto free_ab_and_return;
3236                }
3237                emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3238                strbuf_reset(&header);
3239                if (DIFF_OPT_TST(o, BINARY))
3240                        emit_binary_diff(o, &mf1, &mf2);
3241                else {
3242                        strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3243                                    diff_line_prefix(o), lbl[0], lbl[1]);
3244                        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3245                                         sb.buf, sb.len, 0);
3246                        strbuf_release(&sb);
3247                }
3248                o->found_changes = 1;
3249        } else {
3250                /* Crazy xdl interfaces.. */
3251                const char *diffopts = getenv("GIT_DIFF_OPTS");
3252                const char *v;
3253                xpparam_t xpp;
3254                xdemitconf_t xecfg;
3255                struct emit_callback ecbdata;
3256                const struct userdiff_funcname *pe;
3257
3258                if (must_show_header) {
3259                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3260                                         header.buf, header.len, 0);
3261                        strbuf_reset(&header);
3262                }
3263
3264                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3265                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3266
3267                pe = diff_funcname_pattern(one);
3268                if (!pe)
3269                        pe = diff_funcname_pattern(two);
3270
3271                memset(&xpp, 0, sizeof(xpp));
3272                memset(&xecfg, 0, sizeof(xecfg));
3273                memset(&ecbdata, 0, sizeof(ecbdata));
3274                ecbdata.label_path = lbl;
3275                ecbdata.color_diff = want_color(o->use_color);
3276                ecbdata.ws_rule = whitespace_rule(name_b);
3277                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3278                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
3279                ecbdata.opt = o;
3280                ecbdata.header = header.len ? &header : NULL;
3281                xpp.flags = o->xdl_opts;
3282                xecfg.ctxlen = o->context;
3283                xecfg.interhunkctxlen = o->interhunkcontext;
3284                xecfg.flags = XDL_EMIT_FUNCNAMES;
3285                if (DIFF_OPT_TST(o, FUNCCONTEXT))
3286                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3287                if (pe)
3288                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3289                if (!diffopts)
3290                        ;
3291                else if (skip_prefix(diffopts, "--unified=", &v))
3292                        xecfg.ctxlen = strtoul(v, NULL, 10);
3293                else if (skip_prefix(diffopts, "-u", &v))
3294                        xecfg.ctxlen = strtoul(v, NULL, 10);
3295                if (o->word_diff)
3296                        init_diff_words_data(&ecbdata, o, one, two);
3297                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3298                                  &xpp, &xecfg))
3299                        die("unable to generate diff for %s", one->path);
3300                if (o->word_diff)
3301                        free_diff_words_data(&ecbdata);
3302                if (textconv_one)
3303                        free(mf1.ptr);
3304                if (textconv_two)
3305                        free(mf2.ptr);
3306                xdiff_clear_find_func(&xecfg);
3307        }
3308
3309 free_ab_and_return:
3310        strbuf_release(&header);
3311        diff_free_filespec_data(one);
3312        diff_free_filespec_data(two);
3313        free(a_one);
3314        free(b_two);
3315        return;
3316}
3317
3318static void builtin_diffstat(const char *name_a, const char *name_b,
3319                             struct diff_filespec *one,
3320                             struct diff_filespec *two,
3321                             struct diffstat_t *diffstat,
3322                             struct diff_options *o,
3323                             struct diff_filepair *p)
3324{
3325        mmfile_t mf1, mf2;
3326        struct diffstat_file *data;
3327        int same_contents;
3328        int complete_rewrite = 0;
3329
3330        if (!DIFF_PAIR_UNMERGED(p)) {
3331                if (p->status == DIFF_STATUS_MODIFIED && p->score)
3332                        complete_rewrite = 1;
3333        }
3334
3335        data = diffstat_add(diffstat, name_a, name_b);
3336        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3337
3338        if (!one || !two) {
3339                data->is_unmerged = 1;
3340                return;
3341        }
3342
3343        same_contents = !oidcmp(&one->oid, &two->oid);
3344
3345        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3346                data->is_binary = 1;
3347                if (same_contents) {
3348                        data->added = 0;
3349                        data->deleted = 0;
3350                } else {
3351                        data->added = diff_filespec_size(two);
3352                        data->deleted = diff_filespec_size(one);
3353                }
3354        }
3355
3356        else if (complete_rewrite) {
3357                diff_populate_filespec(one, 0);
3358                diff_populate_filespec(two, 0);
3359                data->deleted = count_lines(one->data, one->size);
3360                data->added = count_lines(two->data, two->size);
3361        }
3362
3363        else if (!same_contents) {
3364                /* Crazy xdl interfaces.. */
3365                xpparam_t xpp;
3366                xdemitconf_t xecfg;
3367
3368                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3369                        die("unable to read files to diff");
3370
3371                memset(&xpp, 0, sizeof(xpp));
3372                memset(&xecfg, 0, sizeof(xecfg));
3373                xpp.flags = o->xdl_opts;
3374                xecfg.ctxlen = o->context;
3375                xecfg.interhunkctxlen = o->interhunkcontext;
3376                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3377                                  &xpp, &xecfg))
3378                        die("unable to generate diffstat for %s", one->path);
3379        }
3380
3381        diff_free_filespec_data(one);
3382        diff_free_filespec_data(two);
3383}
3384
3385static void builtin_checkdiff(const char *name_a, const char *name_b,
3386                              const char *attr_path,
3387                              struct diff_filespec *one,
3388                              struct diff_filespec *two,
3389                              struct diff_options *o)
3390{
3391        mmfile_t mf1, mf2;
3392        struct checkdiff_t data;
3393
3394        if (!two)
3395                return;
3396
3397        memset(&data, 0, sizeof(data));
3398        data.filename = name_b ? name_b : name_a;
3399        data.lineno = 0;
3400        data.o = o;
3401        data.ws_rule = whitespace_rule(attr_path);
3402        data.conflict_marker_size = ll_merge_marker_size(attr_path);
3403
3404        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3405                die("unable to read files to diff");
3406
3407        /*
3408         * All the other codepaths check both sides, but not checking
3409         * the "old" side here is deliberate.  We are checking the newly
3410         * introduced changes, and as long as the "new" side is text, we
3411         * can and should check what it introduces.
3412         */
3413        if (diff_filespec_is_binary(two))
3414                goto free_and_return;
3415        else {
3416                /* Crazy xdl interfaces.. */
3417                xpparam_t xpp;
3418                xdemitconf_t xecfg;
3419
3420                memset(&xpp, 0, sizeof(xpp));
3421                memset(&xecfg, 0, sizeof(xecfg));
3422                xecfg.ctxlen = 1; /* at least one context line */
3423                xpp.flags = 0;
3424                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3425                                  &xpp, &xecfg))
3426                        die("unable to generate checkdiff for %s", one->path);
3427
3428                if (data.ws_rule & WS_BLANK_AT_EOF) {
3429                        struct emit_callback ecbdata;
3430                        int blank_at_eof;
3431
3432                        ecbdata.ws_rule = data.ws_rule;
3433                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
3434                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3435
3436                        if (blank_at_eof) {
3437                                static char *err;
3438                                if (!err)
3439                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
3440                                fprintf(o->file, "%s:%d: %s.\n",
3441                                        data.filename, blank_at_eof, err);
3442                                data.status = 1; /* report errors */
3443                        }
3444                }
3445        }
3446 free_and_return:
3447        diff_free_filespec_data(one);
3448        diff_free_filespec_data(two);
3449        if (data.status)
3450                DIFF_OPT_SET(o, CHECK_FAILED);
3451}
3452
3453struct diff_filespec *alloc_filespec(const char *path)
3454{
3455        struct diff_filespec *spec;
3456
3457        FLEXPTR_ALLOC_STR(spec, path, path);
3458        spec->count = 1;
3459        spec->is_binary = -1;
3460        return spec;
3461}
3462
3463void free_filespec(struct diff_filespec *spec)
3464{
3465        if (!--spec->count) {
3466                diff_free_filespec_data(spec);
3467                free(spec);
3468        }
3469}
3470
3471void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3472                   int oid_valid, unsigned short mode)
3473{
3474        if (mode) {
3475                spec->mode = canon_mode(mode);
3476                oidcpy(&spec->oid, oid);
3477                spec->oid_valid = oid_valid;
3478        }
3479}
3480
3481/*
3482 * Given a name and sha1 pair, if the index tells us the file in
3483 * the work tree has that object contents, return true, so that
3484 * prepare_temp_file() does not have to inflate and extract.
3485 */
3486static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3487{
3488        const struct cache_entry *ce;
3489        struct stat st;
3490        int pos, len;
3491
3492        /*
3493         * We do not read the cache ourselves here, because the
3494         * benchmark with my previous version that always reads cache
3495         * shows that it makes things worse for diff-tree comparing
3496         * two linux-2.6 kernel trees in an already checked out work
3497         * tree.  This is because most diff-tree comparisons deal with
3498         * only a small number of files, while reading the cache is
3499         * expensive for a large project, and its cost outweighs the
3500         * savings we get by not inflating the object to a temporary
3501         * file.  Practically, this code only helps when we are used
3502         * by diff-cache --cached, which does read the cache before
3503         * calling us.
3504         */
3505        if (!active_cache)
3506                return 0;
3507
3508        /* We want to avoid the working directory if our caller
3509         * doesn't need the data in a normal file, this system
3510         * is rather slow with its stat/open/mmap/close syscalls,
3511         * and the object is contained in a pack file.  The pack
3512         * is probably already open and will be faster to obtain
3513         * the data through than the working directory.  Loose
3514         * objects however would tend to be slower as they need
3515         * to be individually opened and inflated.
3516         */
3517        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
3518                return 0;
3519
3520        /*
3521         * Similarly, if we'd have to convert the file contents anyway, that
3522         * makes the optimization not worthwhile.
3523         */
3524        if (!want_file && would_convert_to_git(&the_index, name))
3525                return 0;
3526
3527        len = strlen(name);
3528        pos = cache_name_pos(name, len);
3529        if (pos < 0)
3530                return 0;
3531        ce = active_cache[pos];
3532
3533        /*
3534         * This is not the sha1 we are looking for, or
3535         * unreusable because it is not a regular file.
3536         */
3537        if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3538                return 0;
3539
3540        /*
3541         * If ce is marked as "assume unchanged", there is no
3542         * guarantee that work tree matches what we are looking for.
3543         */
3544        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3545                return 0;
3546
3547        /*
3548         * If ce matches the file in the work tree, we can reuse it.
3549         */
3550        if (ce_uptodate(ce) ||
3551            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3552                return 1;
3553
3554        return 0;
3555}
3556
3557static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3558{
3559        struct strbuf buf = STRBUF_INIT;
3560        char *dirty = "";
3561
3562        /* Are we looking at the work tree? */
3563        if (s->dirty_submodule)
3564                dirty = "-dirty";
3565
3566        strbuf_addf(&buf, "Subproject commit %s%s\n",
3567                    oid_to_hex(&s->oid), dirty);
3568        s->size = buf.len;
3569        if (size_only) {
3570                s->data = NULL;
3571                strbuf_release(&buf);
3572        } else {
3573                s->data = strbuf_detach(&buf, NULL);
3574                s->should_free = 1;
3575        }
3576        return 0;
3577}
3578
3579/*
3580 * While doing rename detection and pickaxe operation, we may need to
3581 * grab the data for the blob (or file) for our own in-core comparison.
3582 * diff_filespec has data and size fields for this purpose.
3583 */
3584int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3585{
3586        int size_only = flags & CHECK_SIZE_ONLY;
3587        int err = 0;
3588        /*
3589         * demote FAIL to WARN to allow inspecting the situation
3590         * instead of refusing.
3591         */
3592        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
3593                                    ? SAFE_CRLF_WARN
3594                                    : safe_crlf);
3595
3596        if (!DIFF_FILE_VALID(s))
3597                die("internal error: asking to populate invalid file.");
3598        if (S_ISDIR(s->mode))
3599                return -1;
3600
3601        if (s->data)
3602                return 0;
3603
3604        if (size_only && 0 < s->size)
3605                return 0;
3606
3607        if (S_ISGITLINK(s->mode))
3608                return diff_populate_gitlink(s, size_only);
3609
3610        if (!s->oid_valid ||
3611            reuse_worktree_file(s->path, &s->oid, 0)) {
3612                struct strbuf buf = STRBUF_INIT;
3613                struct stat st;
3614                int fd;
3615
3616                if (lstat(s->path, &st) < 0) {
3617                        if (errno == ENOENT) {
3618                        err_empty:
3619                                err = -1;
3620                        empty:
3621                                s->data = (char *)"";
3622                                s->size = 0;
3623                                return err;
3624                        }
3625                }
3626                s->size = xsize_t(st.st_size);
3627                if (!s->size)
3628                        goto empty;
3629                if (S_ISLNK(st.st_mode)) {
3630                        struct strbuf sb = STRBUF_INIT;
3631
3632                        if (strbuf_readlink(&sb, s->path, s->size))
3633                                goto err_empty;
3634                        s->size = sb.len;
3635                        s->data = strbuf_detach(&sb, NULL);
3636                        s->should_free = 1;
3637                        return 0;
3638                }
3639
3640                /*
3641                 * Even if the caller would be happy with getting
3642                 * only the size, we cannot return early at this
3643                 * point if the path requires us to run the content
3644                 * conversion.
3645                 */
3646                if (size_only && !would_convert_to_git(&the_index, s->path))
3647                        return 0;
3648
3649                /*
3650                 * Note: this check uses xsize_t(st.st_size) that may
3651                 * not be the true size of the blob after it goes
3652                 * through convert_to_git().  This may not strictly be
3653                 * correct, but the whole point of big_file_threshold
3654                 * and is_binary check being that we want to avoid
3655                 * opening the file and inspecting the contents, this
3656                 * is probably fine.
3657                 */
3658                if ((flags & CHECK_BINARY) &&
3659                    s->size > big_file_threshold && s->is_binary == -1) {
3660                        s->is_binary = 1;
3661                        return 0;
3662                }
3663                fd = open(s->path, O_RDONLY);
3664                if (fd < 0)
3665                        goto err_empty;
3666                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3667                close(fd);
3668                s->should_munmap = 1;
3669
3670                /*
3671                 * Convert from working tree format to canonical git format
3672                 */
3673                if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
3674                        size_t size = 0;
3675                        munmap(s->data, s->size);
3676                        s->should_munmap = 0;
3677                        s->data = strbuf_detach(&buf, &size);
3678                        s->size = size;
3679                        s->should_free = 1;
3680                }
3681        }
3682        else {
3683                enum object_type type;
3684                if (size_only || (flags & CHECK_BINARY)) {
3685                        type = sha1_object_info(s->oid.hash, &s->size);
3686                        if (type < 0)
3687                                die("unable to read %s",
3688                                    oid_to_hex(&s->oid));
3689                        if (size_only)
3690                                return 0;
3691                        if (s->size > big_file_threshold && s->is_binary == -1) {
3692                                s->is_binary = 1;
3693                                return 0;
3694                        }
3695                }
3696                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3697                if (!s->data)
3698                        die("unable to read %s", oid_to_hex(&s->oid));
3699                s->should_free = 1;
3700        }
3701        return 0;
3702}
3703
3704void diff_free_filespec_blob(struct diff_filespec *s)
3705{
3706        if (s->should_free)
3707                free(s->data);
3708        else if (s->should_munmap)
3709                munmap(s->data, s->size);
3710
3711        if (s->should_free || s->should_munmap) {
3712                s->should_free = s->should_munmap = 0;
3713                s->data = NULL;
3714        }
3715}
3716
3717void diff_free_filespec_data(struct diff_filespec *s)
3718{
3719        diff_free_filespec_blob(s);
3720        FREE_AND_NULL(s->cnt_data);
3721}
3722
3723static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3724                           void *blob,
3725                           unsigned long size,
3726                           const struct object_id *oid,
3727                           int mode)
3728{
3729        struct strbuf buf = STRBUF_INIT;
3730        struct strbuf template = STRBUF_INIT;
3731        char *path_dup = xstrdup(path);
3732        const char *base = basename(path_dup);
3733
3734        /* Generate "XXXXXX_basename.ext" */
3735        strbuf_addstr(&template, "XXXXXX_");
3736        strbuf_addstr(&template, base);
3737
3738        temp->tempfile = mks_tempfile_ts(template.buf, strlen(base) + 1);
3739        if (!temp->tempfile)
3740                die_errno("unable to create temp-file");
3741        if (convert_to_working_tree(path,
3742                        (const char *)blob, (size_t)size, &buf)) {
3743                blob = buf.buf;
3744                size = buf.len;
3745        }
3746        if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
3747            close_tempfile_gently(temp->tempfile))
3748                die_errno("unable to write temp-file");
3749        temp->name = get_tempfile_path(temp->tempfile);
3750        oid_to_hex_r(temp->hex, oid);
3751        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3752        strbuf_release(&buf);
3753        strbuf_release(&template);
3754        free(path_dup);
3755}
3756
3757static struct diff_tempfile *prepare_temp_file(const char *name,
3758                struct diff_filespec *one)
3759{
3760        struct diff_tempfile *temp = claim_diff_tempfile();
3761
3762        if (!DIFF_FILE_VALID(one)) {
3763        not_a_valid_file:
3764                /* A '-' entry produces this for file-2, and
3765                 * a '+' entry produces this for file-1.
3766                 */
3767                temp->name = "/dev/null";
3768                xsnprintf(temp->hex, sizeof(temp->hex), ".");
3769                xsnprintf(temp->mode, sizeof(temp->mode), ".");
3770                return temp;
3771        }
3772
3773        if (!S_ISGITLINK(one->mode) &&
3774            (!one->oid_valid ||
3775             reuse_worktree_file(name, &one->oid, 1))) {
3776                struct stat st;
3777                if (lstat(name, &st) < 0) {
3778                        if (errno == ENOENT)
3779                                goto not_a_valid_file;
3780                        die_errno("stat(%s)", name);
3781                }
3782                if (S_ISLNK(st.st_mode)) {
3783                        struct strbuf sb = STRBUF_INIT;
3784                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
3785                                die_errno("readlink(%s)", name);
3786                        prep_temp_blob(name, temp, sb.buf, sb.len,
3787                                       (one->oid_valid ?
3788                                        &one->oid : &null_oid),
3789                                       (one->oid_valid ?
3790                                        one->mode : S_IFLNK));
3791                        strbuf_release(&sb);
3792                }
3793                else {
3794                        /* we can borrow from the file in the work tree */
3795                        temp->name = name;
3796                        if (!one->oid_valid)
3797                                oid_to_hex_r(temp->hex, &null_oid);
3798                        else
3799                                oid_to_hex_r(temp->hex, &one->oid);
3800                        /* Even though we may sometimes borrow the
3801                         * contents from the work tree, we always want
3802                         * one->mode.  mode is trustworthy even when
3803                         * !(one->oid_valid), as long as
3804                         * DIFF_FILE_VALID(one).
3805                         */
3806                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3807                }
3808                return temp;
3809        }
3810        else {
3811                if (diff_populate_filespec(one, 0))
3812                        die("cannot read data blob for %s", one->path);
3813                prep_temp_blob(name, temp, one->data, one->size,
3814                               &one->oid, one->mode);
3815        }
3816        return temp;
3817}
3818
3819static void add_external_diff_name(struct argv_array *argv,
3820                                   const char *name,
3821                                   struct diff_filespec *df)
3822{
3823        struct diff_tempfile *temp = prepare_temp_file(name, df);
3824        argv_array_push(argv, temp->name);
3825        argv_array_push(argv, temp->hex);
3826        argv_array_push(argv, temp->mode);
3827}
3828
3829/* An external diff command takes:
3830 *
3831 * diff-cmd name infile1 infile1-sha1 infile1-mode \
3832 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3833 *
3834 */
3835static void run_external_diff(const char *pgm,
3836                              const char *name,
3837                              const char *other,
3838                              struct diff_filespec *one,
3839                              struct diff_filespec *two,
3840                              const char *xfrm_msg,
3841                              int complete_rewrite,
3842                              struct diff_options *o)
3843{
3844        struct argv_array argv = ARGV_ARRAY_INIT;
3845        struct argv_array env = ARGV_ARRAY_INIT;
3846        struct diff_queue_struct *q = &diff_queued_diff;
3847
3848        argv_array_push(&argv, pgm);
3849        argv_array_push(&argv, name);
3850
3851        if (one && two) {
3852                add_external_diff_name(&argv, name, one);
3853                if (!other)
3854                        add_external_diff_name(&argv, name, two);
3855                else {
3856                        add_external_diff_name(&argv, other, two);
3857                        argv_array_push(&argv, other);
3858                        argv_array_push(&argv, xfrm_msg);
3859                }
3860        }
3861
3862        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3863        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3864
3865        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3866                die(_("external diff died, stopping at %s"), name);
3867
3868        remove_tempfile();
3869        argv_array_clear(&argv);
3870        argv_array_clear(&env);
3871}
3872
3873static int similarity_index(struct diff_filepair *p)
3874{
3875        return p->score * 100 / MAX_SCORE;
3876}
3877
3878static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3879{
3880        if (startup_info->have_repository)
3881                return find_unique_abbrev(oid->hash, abbrev);
3882        else {
3883                char *hex = oid_to_hex(oid);
3884                if (abbrev < 0)
3885                        abbrev = FALLBACK_DEFAULT_ABBREV;
3886                if (abbrev > GIT_SHA1_HEXSZ)
3887                        die("BUG: oid abbreviation out of range: %d", abbrev);
3888                if (abbrev)
3889                        hex[abbrev] = '\0';
3890                return hex;
3891        }
3892}
3893
3894static void fill_metainfo(struct strbuf *msg,
3895                          const char *name,
3896                          const char *other,
3897                          struct diff_filespec *one,
3898                          struct diff_filespec *two,
3899                          struct diff_options *o,
3900                          struct diff_filepair *p,
3901                          int *must_show_header,
3902                          int use_color)
3903{
3904        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3905        const char *reset = diff_get_color(use_color, DIFF_RESET);
3906        const char *line_prefix = diff_line_prefix(o);
3907
3908        *must_show_header = 1;
3909        strbuf_init(msg, PATH_MAX * 2 + 300);
3910        switch (p->status) {
3911        case DIFF_STATUS_COPIED:
3912                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3913                            line_prefix, set, similarity_index(p));
3914                strbuf_addf(msg, "%s\n%s%scopy from ",
3915                            reset,  line_prefix, set);
3916                quote_c_style(name, msg, NULL, 0);
3917                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3918                quote_c_style(other, msg, NULL, 0);
3919                strbuf_addf(msg, "%s\n", reset);
3920                break;
3921        case DIFF_STATUS_RENAMED:
3922                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3923                            line_prefix, set, similarity_index(p));
3924                strbuf_addf(msg, "%s\n%s%srename from ",
3925                            reset, line_prefix, set);
3926                quote_c_style(name, msg, NULL, 0);
3927                strbuf_addf(msg, "%s\n%s%srename to ",
3928                            reset, line_prefix, set);
3929                quote_c_style(other, msg, NULL, 0);
3930                strbuf_addf(msg, "%s\n", reset);
3931                break;
3932        case DIFF_STATUS_MODIFIED:
3933                if (p->score) {
3934                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3935                                    line_prefix,
3936                                    set, similarity_index(p), reset);
3937                        break;
3938                }
3939                /* fallthru */
3940        default:
3941                *must_show_header = 0;
3942        }
3943        if (one && two && oidcmp(&one->oid, &two->oid)) {
3944                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3945
3946                if (DIFF_OPT_TST(o, BINARY)) {
3947                        mmfile_t mf;
3948                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3949                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3950                                abbrev = 40;
3951                }
3952                strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3953                            diff_abbrev_oid(&one->oid, abbrev),
3954                            diff_abbrev_oid(&two->oid, abbrev));
3955                if (one->mode == two->mode)
3956                        strbuf_addf(msg, " %06o", one->mode);
3957                strbuf_addf(msg, "%s\n", reset);
3958        }
3959}
3960
3961static void run_diff_cmd(const char *pgm,
3962                         const char *name,
3963                         const char *other,
3964                         const char *attr_path,
3965                         struct diff_filespec *one,
3966                         struct diff_filespec *two,
3967                         struct strbuf *msg,
3968                         struct diff_options *o,
3969                         struct diff_filepair *p)
3970{
3971        const char *xfrm_msg = NULL;
3972        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3973        int must_show_header = 0;
3974
3975
3976        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3977                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3978                if (drv && drv->external)
3979                        pgm = drv->external;
3980        }
3981
3982        if (msg) {
3983                /*
3984                 * don't use colors when the header is intended for an
3985                 * external diff driver
3986                 */
3987                fill_metainfo(msg, name, other, one, two, o, p,
3988                              &must_show_header,
3989                              want_color(o->use_color) && !pgm);
3990                xfrm_msg = msg->len ? msg->buf : NULL;
3991        }
3992
3993        if (pgm) {
3994                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3995                                  complete_rewrite, o);
3996                return;
3997        }
3998        if (one && two)
3999                builtin_diff(name, other ? other : name,
4000                             one, two, xfrm_msg, must_show_header,
4001                             o, complete_rewrite);
4002        else
4003                fprintf(o->file, "* Unmerged path %s\n", name);
4004}
4005
4006static void diff_fill_oid_info(struct diff_filespec *one)
4007{
4008        if (DIFF_FILE_VALID(one)) {
4009                if (!one->oid_valid) {
4010                        struct stat st;
4011                        if (one->is_stdin) {
4012                                oidclr(&one->oid);
4013                                return;
4014                        }
4015                        if (lstat(one->path, &st) < 0)
4016                                die_errno("stat '%s'", one->path);
4017                        if (index_path(&one->oid, one->path, &st, 0))
4018                                die("cannot hash %s", one->path);
4019                }
4020        }
4021        else
4022                oidclr(&one->oid);
4023}
4024
4025static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4026{
4027        /* Strip the prefix but do not molest /dev/null and absolute paths */
4028        if (*namep && **namep != '/') {
4029                *namep += prefix_length;
4030                if (**namep == '/')
4031                        ++*namep;
4032        }
4033        if (*otherp && **otherp != '/') {
4034                *otherp += prefix_length;
4035                if (**otherp == '/')
4036                        ++*otherp;
4037        }
4038}
4039
4040static void run_diff(struct diff_filepair *p, struct diff_options *o)
4041{
4042        const char *pgm = external_diff();
4043        struct strbuf msg;
4044        struct diff_filespec *one = p->one;
4045        struct diff_filespec *two = p->two;
4046        const char *name;
4047        const char *other;
4048        const char *attr_path;
4049
4050        name  = one->path;
4051        other = (strcmp(name, two->path) ? two->path : NULL);
4052        attr_path = name;
4053        if (o->prefix_length)
4054                strip_prefix(o->prefix_length, &name, &other);
4055
4056        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
4057                pgm = NULL;
4058
4059        if (DIFF_PAIR_UNMERGED(p)) {
4060                run_diff_cmd(pgm, name, NULL, attr_path,
4061                             NULL, NULL, NULL, o, p);
4062                return;
4063        }
4064
4065        diff_fill_oid_info(one);
4066        diff_fill_oid_info(two);
4067
4068        if (!pgm &&
4069            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4070            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4071                /*
4072                 * a filepair that changes between file and symlink
4073                 * needs to be split into deletion and creation.
4074                 */
4075                struct diff_filespec *null = alloc_filespec(two->path);
4076                run_diff_cmd(NULL, name, other, attr_path,
4077                             one, null, &msg, o, p);
4078                free(null);
4079                strbuf_release(&msg);
4080
4081                null = alloc_filespec(one->path);
4082                run_diff_cmd(NULL, name, other, attr_path,
4083                             null, two, &msg, o, p);
4084                free(null);
4085        }
4086        else
4087                run_diff_cmd(pgm, name, other, attr_path,
4088                             one, two, &msg, o, p);
4089
4090        strbuf_release(&msg);
4091}
4092
4093static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4094                         struct diffstat_t *diffstat)
4095{
4096        const char *name;
4097        const char *other;
4098
4099        if (DIFF_PAIR_UNMERGED(p)) {
4100                /* unmerged */
4101                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4102                return;
4103        }
4104
4105        name = p->one->path;
4106        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4107
4108        if (o->prefix_length)
4109                strip_prefix(o->prefix_length, &name, &other);
4110
4111        diff_fill_oid_info(p->one);
4112        diff_fill_oid_info(p->two);
4113
4114        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4115}
4116
4117static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4118{
4119        const char *name;
4120        const char *other;
4121        const char *attr_path;
4122
4123        if (DIFF_PAIR_UNMERGED(p)) {
4124                /* unmerged */
4125                return;
4126        }
4127
4128        name = p->one->path;
4129        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4130        attr_path = other ? other : name;
4131
4132        if (o->prefix_length)
4133                strip_prefix(o->prefix_length, &name, &other);
4134
4135        diff_fill_oid_info(p->one);
4136        diff_fill_oid_info(p->two);
4137
4138        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4139}
4140
4141void diff_setup(struct diff_options *options)
4142{
4143        memcpy(options, &default_diff_options, sizeof(*options));
4144
4145        options->file = stdout;
4146
4147        options->abbrev = DEFAULT_ABBREV;
4148        options->line_termination = '\n';
4149        options->break_opt = -1;
4150        options->rename_limit = -1;
4151        options->dirstat_permille = diff_dirstat_permille_default;
4152        options->context = diff_context_default;
4153        options->interhunkcontext = diff_interhunk_context_default;
4154        options->ws_error_highlight = ws_error_highlight_default;
4155        DIFF_OPT_SET(options, RENAME_EMPTY);
4156
4157        /* pathchange left =NULL by default */
4158        options->change = diff_change;
4159        options->add_remove = diff_addremove;
4160        options->use_color = diff_use_color_default;
4161        options->detect_rename = diff_detect_rename_default;
4162        options->xdl_opts |= diff_algorithm;
4163        if (diff_indent_heuristic)
4164                DIFF_XDL_SET(options, INDENT_HEURISTIC);
4165
4166        options->orderfile = diff_order_file_cfg;
4167
4168        if (diff_no_prefix) {
4169                options->a_prefix = options->b_prefix = "";
4170        } else if (!diff_mnemonic_prefix) {
4171                options->a_prefix = "a/";
4172                options->b_prefix = "b/";
4173        }
4174
4175        options->color_moved = diff_color_moved_default;
4176}
4177
4178void diff_setup_done(struct diff_options *options)
4179{
4180        int count = 0;
4181
4182        if (options->set_default)
4183                options->set_default(options);
4184
4185        if (options->output_format & DIFF_FORMAT_NAME)
4186                count++;
4187        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
4188                count++;
4189        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
4190                count++;
4191        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
4192                count++;
4193        if (count > 1)
4194                die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4195
4196        /*
4197         * Most of the time we can say "there are changes"
4198         * only by checking if there are changed paths, but
4199         * --ignore-whitespace* options force us to look
4200         * inside contents.
4201         */
4202
4203        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
4204            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
4205            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
4206                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
4207        else
4208                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
4209
4210        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
4211                options->detect_rename = DIFF_DETECT_COPY;
4212
4213        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
4214                options->prefix = NULL;
4215        if (options->prefix)
4216                options->prefix_length = strlen(options->prefix);
4217        else
4218                options->prefix_length = 0;
4219
4220        if (options->output_format & (DIFF_FORMAT_NAME |
4221                                      DIFF_FORMAT_NAME_STATUS |
4222                                      DIFF_FORMAT_CHECKDIFF |
4223                                      DIFF_FORMAT_NO_OUTPUT))
4224                options->output_format &= ~(DIFF_FORMAT_RAW |
4225                                            DIFF_FORMAT_NUMSTAT |
4226                                            DIFF_FORMAT_DIFFSTAT |
4227                                            DIFF_FORMAT_SHORTSTAT |
4228                                            DIFF_FORMAT_DIRSTAT |
4229                                            DIFF_FORMAT_SUMMARY |
4230                                            DIFF_FORMAT_PATCH);
4231
4232        /*
4233         * These cases always need recursive; we do not drop caller-supplied
4234         * recursive bits for other formats here.
4235         */
4236        if (options->output_format & (DIFF_FORMAT_PATCH |
4237                                      DIFF_FORMAT_NUMSTAT |
4238                                      DIFF_FORMAT_DIFFSTAT |
4239                                      DIFF_FORMAT_SHORTSTAT |
4240                                      DIFF_FORMAT_DIRSTAT |
4241                                      DIFF_FORMAT_SUMMARY |
4242                                      DIFF_FORMAT_CHECKDIFF))
4243                DIFF_OPT_SET(options, RECURSIVE);
4244        /*
4245         * Also pickaxe would not work very well if you do not say recursive
4246         */
4247        if (options->pickaxe)
4248                DIFF_OPT_SET(options, RECURSIVE);
4249        /*
4250         * When patches are generated, submodules diffed against the work tree
4251         * must be checked for dirtiness too so it can be shown in the output
4252         */
4253        if (options->output_format & DIFF_FORMAT_PATCH)
4254                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
4255
4256        if (options->detect_rename && options->rename_limit < 0)
4257                options->rename_limit = diff_rename_limit_default;
4258        if (options->setup & DIFF_SETUP_USE_CACHE) {
4259                if (!active_cache)
4260                        /* read-cache does not die even when it fails
4261                         * so it is safe for us to do this here.  Also
4262                         * it does not smudge active_cache or active_nr
4263                         * when it fails, so we do not have to worry about
4264                         * cleaning it up ourselves either.
4265                         */
4266                        read_cache();
4267        }
4268        if (40 < options->abbrev)
4269                options->abbrev = 40; /* full */
4270
4271        /*
4272         * It does not make sense to show the first hit we happened
4273         * to have found.  It does not make sense not to return with
4274         * exit code in such a case either.
4275         */
4276        if (DIFF_OPT_TST(options, QUICK)) {
4277                options->output_format = DIFF_FORMAT_NO_OUTPUT;
4278                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4279        }
4280
4281        options->diff_path_counter = 0;
4282
4283        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
4284                die(_("--follow requires exactly one pathspec"));
4285
4286        if (!options->use_color || external_diff())
4287                options->color_moved = 0;
4288}
4289
4290static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4291{
4292        char c, *eq;
4293        int len;
4294
4295        if (*arg != '-')
4296                return 0;
4297        c = *++arg;
4298        if (!c)
4299                return 0;
4300        if (c == arg_short) {
4301                c = *++arg;
4302                if (!c)
4303                        return 1;
4304                if (val && isdigit(c)) {
4305                        char *end;
4306                        int n = strtoul(arg, &end, 10);
4307                        if (*end)
4308                                return 0;
4309                        *val = n;
4310                        return 1;
4311                }
4312                return 0;
4313        }
4314        if (c != '-')
4315                return 0;
4316        arg++;
4317        eq = strchrnul(arg, '=');
4318        len = eq - arg;
4319        if (!len || strncmp(arg, arg_long, len))
4320                return 0;
4321        if (*eq) {
4322                int n;
4323                char *end;
4324                if (!isdigit(*++eq))
4325                        return 0;
4326                n = strtoul(eq, &end, 10);
4327                if (*end)
4328                        return 0;
4329                *val = n;
4330        }
4331        return 1;
4332}
4333
4334static int diff_scoreopt_parse(const char *opt);
4335
4336static inline int short_opt(char opt, const char **argv,
4337                            const char **optarg)
4338{
4339        const char *arg = argv[0];
4340        if (arg[0] != '-' || arg[1] != opt)
4341                return 0;
4342        if (arg[2] != '\0') {
4343                *optarg = arg + 2;
4344                return 1;
4345        }
4346        if (!argv[1])
4347                die("Option '%c' requires a value", opt);
4348        *optarg = argv[1];
4349        return 2;
4350}
4351
4352int parse_long_opt(const char *opt, const char **argv,
4353                   const char **optarg)
4354{
4355        const char *arg = argv[0];
4356        if (!skip_prefix(arg, "--", &arg))
4357                return 0;
4358        if (!skip_prefix(arg, opt, &arg))
4359                return 0;
4360        if (*arg == '=') { /* stuck form: --option=value */
4361                *optarg = arg + 1;
4362                return 1;
4363        }
4364        if (*arg != '\0')
4365                return 0;
4366        /* separate form: --option value */
4367        if (!argv[1])
4368                die("Option '--%s' requires a value", opt);
4369        *optarg = argv[1];
4370        return 2;
4371}
4372
4373static int stat_opt(struct diff_options *options, const char **av)
4374{
4375        const char *arg = av[0];
4376        char *end;
4377        int width = options->stat_width;
4378        int name_width = options->stat_name_width;
4379        int graph_width = options->stat_graph_width;
4380        int count = options->stat_count;
4381        int argcount = 1;
4382
4383        if (!skip_prefix(arg, "--stat", &arg))
4384                die("BUG: stat option does not begin with --stat: %s", arg);
4385        end = (char *)arg;
4386
4387        switch (*arg) {
4388        case '-':
4389                if (skip_prefix(arg, "-width", &arg)) {
4390                        if (*arg == '=')
4391                                width = strtoul(arg + 1, &end, 10);
4392                        else if (!*arg && !av[1])
4393                                die_want_option("--stat-width");
4394                        else if (!*arg) {
4395                                width = strtoul(av[1], &end, 10);
4396                                argcount = 2;
4397                        }
4398                } else if (skip_prefix(arg, "-name-width", &arg)) {
4399                        if (*arg == '=')
4400                                name_width = strtoul(arg + 1, &end, 10);
4401                        else if (!*arg && !av[1])
4402                                die_want_option("--stat-name-width");
4403                        else if (!*arg) {
4404                                name_width = strtoul(av[1], &end, 10);
4405                                argcount = 2;
4406                        }
4407                } else if (skip_prefix(arg, "-graph-width", &arg)) {
4408                        if (*arg == '=')
4409                                graph_width = strtoul(arg + 1, &end, 10);
4410                        else if (!*arg && !av[1])
4411                                die_want_option("--stat-graph-width");
4412                        else if (!*arg) {
4413                                graph_width = strtoul(av[1], &end, 10);
4414                                argcount = 2;
4415                        }
4416                } else if (skip_prefix(arg, "-count", &arg)) {
4417                        if (*arg == '=')
4418                                count = strtoul(arg + 1, &end, 10);
4419                        else if (!*arg && !av[1])
4420                                die_want_option("--stat-count");
4421                        else if (!*arg) {
4422                                count = strtoul(av[1], &end, 10);
4423                                argcount = 2;
4424                        }
4425                }
4426                break;
4427        case '=':
4428                width = strtoul(arg+1, &end, 10);
4429                if (*end == ',')
4430                        name_width = strtoul(end+1, &end, 10);
4431                if (*end == ',')
4432                        count = strtoul(end+1, &end, 10);
4433        }
4434
4435        /* Important! This checks all the error cases! */
4436        if (*end)
4437                return 0;
4438        options->output_format |= DIFF_FORMAT_DIFFSTAT;
4439        options->stat_name_width = name_width;
4440        options->stat_graph_width = graph_width;
4441        options->stat_width = width;
4442        options->stat_count = count;
4443        return argcount;
4444}
4445
4446static int parse_dirstat_opt(struct diff_options *options, const char *params)
4447{
4448        struct strbuf errmsg = STRBUF_INIT;
4449        if (parse_dirstat_params(options, params, &errmsg))
4450                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4451                    errmsg.buf);
4452        strbuf_release(&errmsg);
4453        /*
4454         * The caller knows a dirstat-related option is given from the command
4455         * line; allow it to say "return this_function();"
4456         */
4457        options->output_format |= DIFF_FORMAT_DIRSTAT;
4458        return 1;
4459}
4460
4461static int parse_submodule_opt(struct diff_options *options, const char *value)
4462{
4463        if (parse_submodule_params(options, value))
4464                die(_("Failed to parse --submodule option parameter: '%s'"),
4465                        value);
4466        return 1;
4467}
4468
4469static const char diff_status_letters[] = {
4470        DIFF_STATUS_ADDED,
4471        DIFF_STATUS_COPIED,
4472        DIFF_STATUS_DELETED,
4473        DIFF_STATUS_MODIFIED,
4474        DIFF_STATUS_RENAMED,
4475        DIFF_STATUS_TYPE_CHANGED,
4476        DIFF_STATUS_UNKNOWN,
4477        DIFF_STATUS_UNMERGED,
4478        DIFF_STATUS_FILTER_AON,
4479        DIFF_STATUS_FILTER_BROKEN,
4480        '\0',
4481};
4482
4483static unsigned int filter_bit['Z' + 1];
4484
4485static void prepare_filter_bits(void)
4486{
4487        int i;
4488
4489        if (!filter_bit[DIFF_STATUS_ADDED]) {
4490                for (i = 0; diff_status_letters[i]; i++)
4491                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
4492        }
4493}
4494
4495static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4496{
4497        return opt->filter & filter_bit[(int) status];
4498}
4499
4500static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4501{
4502        int i, optch;
4503
4504        prepare_filter_bits();
4505
4506        /*
4507         * If there is a negation e.g. 'd' in the input, and we haven't
4508         * initialized the filter field with another --diff-filter, start
4509         * from full set of bits, except for AON.
4510         */
4511        if (!opt->filter) {
4512                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4513                        if (optch < 'a' || 'z' < optch)
4514                                continue;
4515                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4516                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4517                        break;
4518                }
4519        }
4520
4521        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4522                unsigned int bit;
4523                int negate;
4524
4525                if ('a' <= optch && optch <= 'z') {
4526                        negate = 1;
4527                        optch = toupper(optch);
4528                } else {
4529                        negate = 0;
4530                }
4531
4532                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4533                if (!bit)
4534                        return optarg[i];
4535                if (negate)
4536                        opt->filter &= ~bit;
4537                else
4538                        opt->filter |= bit;
4539        }
4540        return 0;
4541}
4542
4543static void enable_patch_output(int *fmt) {
4544        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4545        *fmt |= DIFF_FORMAT_PATCH;
4546}
4547
4548static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4549{
4550        int val = parse_ws_error_highlight(arg);
4551
4552        if (val < 0) {
4553                error("unknown value after ws-error-highlight=%.*s",
4554                      -1 - val, arg);
4555                return 0;
4556        }
4557        opt->ws_error_highlight = val;
4558        return 1;
4559}
4560
4561int diff_opt_parse(struct diff_options *options,
4562                   const char **av, int ac, const char *prefix)
4563{
4564        const char *arg = av[0];
4565        const char *optarg;
4566        int argcount;
4567
4568        if (!prefix)
4569                prefix = "";
4570
4571        /* Output format options */
4572        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4573            || opt_arg(arg, 'U', "unified", &options->context))
4574                enable_patch_output(&options->output_format);
4575        else if (!strcmp(arg, "--raw"))
4576                options->output_format |= DIFF_FORMAT_RAW;
4577        else if (!strcmp(arg, "--patch-with-raw")) {
4578                enable_patch_output(&options->output_format);
4579                options->output_format |= DIFF_FORMAT_RAW;
4580        } else if (!strcmp(arg, "--numstat"))
4581                options->output_format |= DIFF_FORMAT_NUMSTAT;
4582        else if (!strcmp(arg, "--shortstat"))
4583                options->output_format |= DIFF_FORMAT_SHORTSTAT;
4584        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
4585                return parse_dirstat_opt(options, "");
4586        else if (skip_prefix(arg, "-X", &arg))
4587                return parse_dirstat_opt(options, arg);
4588        else if (skip_prefix(arg, "--dirstat=", &arg))
4589                return parse_dirstat_opt(options, arg);
4590        else if (!strcmp(arg, "--cumulative"))
4591                return parse_dirstat_opt(options, "cumulative");
4592        else if (!strcmp(arg, "--dirstat-by-file"))
4593                return parse_dirstat_opt(options, "files");
4594        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
4595                parse_dirstat_opt(options, "files");
4596                return parse_dirstat_opt(options, arg);
4597        }
4598        else if (!strcmp(arg, "--check"))
4599                options->output_format |= DIFF_FORMAT_CHECKDIFF;
4600        else if (!strcmp(arg, "--summary"))
4601                options->output_format |= DIFF_FORMAT_SUMMARY;
4602        else if (!strcmp(arg, "--patch-with-stat")) {
4603                enable_patch_output(&options->output_format);
4604                options->output_format |= DIFF_FORMAT_DIFFSTAT;
4605        } else if (!strcmp(arg, "--name-only"))
4606                options->output_format |= DIFF_FORMAT_NAME;
4607        else if (!strcmp(arg, "--name-status"))
4608                options->output_format |= DIFF_FORMAT_NAME_STATUS;
4609        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4610                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4611        else if (starts_with(arg, "--stat"))
4612                /* --stat, --stat-width, --stat-name-width, or --stat-count */
4613                return stat_opt(options, av);
4614
4615        /* renames options */
4616        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
4617                 !strcmp(arg, "--break-rewrites")) {
4618                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4619                        return error("invalid argument to -B: %s", arg+2);
4620        }
4621        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
4622                 !strcmp(arg, "--find-renames")) {
4623                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4624                        return error("invalid argument to -M: %s", arg+2);
4625                options->detect_rename = DIFF_DETECT_RENAME;
4626        }
4627        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4628                options->irreversible_delete = 1;
4629        }
4630        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
4631                 !strcmp(arg, "--find-copies")) {
4632                if (options->detect_rename == DIFF_DETECT_COPY)
4633                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4634                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4635                        return error("invalid argument to -C: %s", arg+2);
4636                options->detect_rename = DIFF_DETECT_COPY;
4637        }
4638        else if (!strcmp(arg, "--no-renames"))
4639                options->detect_rename = 0;
4640        else if (!strcmp(arg, "--rename-empty"))
4641                DIFF_OPT_SET(options, RENAME_EMPTY);
4642        else if (!strcmp(arg, "--no-rename-empty"))
4643                DIFF_OPT_CLR(options, RENAME_EMPTY);
4644        else if (!strcmp(arg, "--relative"))
4645                DIFF_OPT_SET(options, RELATIVE_NAME);
4646        else if (skip_prefix(arg, "--relative=", &arg)) {
4647                DIFF_OPT_SET(options, RELATIVE_NAME);
4648                options->prefix = arg;
4649        }
4650
4651        /* xdiff options */
4652        else if (!strcmp(arg, "--minimal"))
4653                DIFF_XDL_SET(options, NEED_MINIMAL);
4654        else if (!strcmp(arg, "--no-minimal"))
4655                DIFF_XDL_CLR(options, NEED_MINIMAL);
4656        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4657                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4658        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4659                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4660        else if (!strcmp(arg, "--ignore-space-at-eol"))
4661                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4662        else if (!strcmp(arg, "--ignore-blank-lines"))
4663                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4664        else if (!strcmp(arg, "--indent-heuristic"))
4665                DIFF_XDL_SET(options, INDENT_HEURISTIC);
4666        else if (!strcmp(arg, "--no-indent-heuristic"))
4667                DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4668        else if (!strcmp(arg, "--patience"))
4669                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4670        else if (!strcmp(arg, "--histogram"))
4671                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4672        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4673                long value = parse_algorithm_value(optarg);
4674                if (value < 0)
4675                        return error("option diff-algorithm accepts \"myers\", "
4676                                     "\"minimal\", \"patience\" and \"histogram\"");
4677                /* clear out previous settings */
4678                DIFF_XDL_CLR(options, NEED_MINIMAL);
4679                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4680                options->xdl_opts |= value;
4681                return argcount;
4682        }
4683
4684        /* flags options */
4685        else if (!strcmp(arg, "--binary")) {
4686                enable_patch_output(&options->output_format);
4687                DIFF_OPT_SET(options, BINARY);
4688        }
4689        else if (!strcmp(arg, "--full-index"))
4690                DIFF_OPT_SET(options, FULL_INDEX);
4691        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4692                DIFF_OPT_SET(options, TEXT);
4693        else if (!strcmp(arg, "-R"))
4694                DIFF_OPT_SET(options, REVERSE_DIFF);
4695        else if (!strcmp(arg, "--find-copies-harder"))
4696                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4697        else if (!strcmp(arg, "--follow"))
4698                DIFF_OPT_SET(options, FOLLOW_RENAMES);
4699        else if (!strcmp(arg, "--no-follow")) {
4700                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
4701                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
4702        } else if (!strcmp(arg, "--color"))
4703                options->use_color = 1;
4704        else if (skip_prefix(arg, "--color=", &arg)) {
4705                int value = git_config_colorbool(NULL, arg);
4706                if (value < 0)
4707                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
4708                options->use_color = value;
4709        }
4710        else if (!strcmp(arg, "--no-color"))
4711                options->use_color = 0;
4712        else if (!strcmp(arg, "--color-moved")) {
4713                if (diff_color_moved_default)
4714                        options->color_moved = diff_color_moved_default;
4715                if (options->color_moved == COLOR_MOVED_NO)
4716                        options->color_moved = COLOR_MOVED_DEFAULT;
4717        } else if (!strcmp(arg, "--no-color-moved"))
4718                options->color_moved = COLOR_MOVED_NO;
4719        else if (skip_prefix(arg, "--color-moved=", &arg)) {
4720                int cm = parse_color_moved(arg);
4721                if (cm < 0)
4722                        die("bad --color-moved argument: %s", arg);
4723                options->color_moved = cm;
4724        } else if (!strcmp(arg, "--color-words")) {
4725                options->use_color = 1;
4726                options->word_diff = DIFF_WORDS_COLOR;
4727        }
4728        else if (skip_prefix(arg, "--color-words=", &arg)) {
4729                options->use_color = 1;
4730                options->word_diff = DIFF_WORDS_COLOR;
4731                options->word_regex = arg;
4732        }
4733        else if (!strcmp(arg, "--word-diff")) {
4734                if (options->word_diff == DIFF_WORDS_NONE)
4735                        options->word_diff = DIFF_WORDS_PLAIN;
4736        }
4737        else if (skip_prefix(arg, "--word-diff=", &arg)) {
4738                if (!strcmp(arg, "plain"))
4739                        options->word_diff = DIFF_WORDS_PLAIN;
4740                else if (!strcmp(arg, "color")) {
4741                        options->use_color = 1;
4742                        options->word_diff = DIFF_WORDS_COLOR;
4743                }
4744                else if (!strcmp(arg, "porcelain"))
4745                        options->word_diff = DIFF_WORDS_PORCELAIN;
4746                else if (!strcmp(arg, "none"))
4747                        options->word_diff = DIFF_WORDS_NONE;
4748                else
4749                        die("bad --word-diff argument: %s", arg);
4750        }
4751        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4752                if (options->word_diff == DIFF_WORDS_NONE)
4753                        options->word_diff = DIFF_WORDS_PLAIN;
4754                options->word_regex = optarg;
4755                return argcount;
4756        }
4757        else if (!strcmp(arg, "--exit-code"))
4758                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4759        else if (!strcmp(arg, "--quiet"))
4760                DIFF_OPT_SET(options, QUICK);
4761        else if (!strcmp(arg, "--ext-diff"))
4762                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4763        else if (!strcmp(arg, "--no-ext-diff"))
4764                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4765        else if (!strcmp(arg, "--textconv"))
4766                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4767        else if (!strcmp(arg, "--no-textconv"))
4768                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4769        else if (!strcmp(arg, "--ignore-submodules")) {
4770                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4771                handle_ignore_submodules_arg(options, "all");
4772        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4773                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4774                handle_ignore_submodules_arg(options, arg);
4775        } else if (!strcmp(arg, "--submodule"))
4776                options->submodule_format = DIFF_SUBMODULE_LOG;
4777        else if (skip_prefix(arg, "--submodule=", &arg))
4778                return parse_submodule_opt(options, arg);
4779        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4780                return parse_ws_error_highlight_opt(options, arg);
4781        else if (!strcmp(arg, "--ita-invisible-in-index"))
4782                options->ita_invisible_in_index = 1;
4783        else if (!strcmp(arg, "--ita-visible-in-index"))
4784                options->ita_invisible_in_index = 0;
4785
4786        /* misc options */
4787        else if (!strcmp(arg, "-z"))
4788                options->line_termination = 0;
4789        else if ((argcount = short_opt('l', av, &optarg))) {
4790                options->rename_limit = strtoul(optarg, NULL, 10);
4791                return argcount;
4792        }
4793        else if ((argcount = short_opt('S', av, &optarg))) {
4794                options->pickaxe = optarg;
4795                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4796                return argcount;
4797        } else if ((argcount = short_opt('G', av, &optarg))) {
4798                options->pickaxe = optarg;
4799                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4800                return argcount;
4801        }
4802        else if (!strcmp(arg, "--pickaxe-all"))
4803                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4804        else if (!strcmp(arg, "--pickaxe-regex"))
4805                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4806        else if ((argcount = short_opt('O', av, &optarg))) {
4807                options->orderfile = prefix_filename(prefix, optarg);
4808                return argcount;
4809        }
4810        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4811                int offending = parse_diff_filter_opt(optarg, options);
4812                if (offending)
4813                        die("unknown change class '%c' in --diff-filter=%s",
4814                            offending, optarg);
4815                return argcount;
4816        }
4817        else if (!strcmp(arg, "--no-abbrev"))
4818                options->abbrev = 0;
4819        else if (!strcmp(arg, "--abbrev"))
4820                options->abbrev = DEFAULT_ABBREV;
4821        else if (skip_prefix(arg, "--abbrev=", &arg)) {
4822                options->abbrev = strtoul(arg, NULL, 10);
4823                if (options->abbrev < MINIMUM_ABBREV)
4824                        options->abbrev = MINIMUM_ABBREV;
4825                else if (40 < options->abbrev)
4826                        options->abbrev = 40;
4827        }
4828        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4829                options->a_prefix = optarg;
4830                return argcount;
4831        }
4832        else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4833                options->line_prefix = optarg;
4834                options->line_prefix_length = strlen(options->line_prefix);
4835                graph_setup_line_prefix(options);
4836                return argcount;
4837        }
4838        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4839                options->b_prefix = optarg;
4840                return argcount;
4841        }
4842        else if (!strcmp(arg, "--no-prefix"))
4843                options->a_prefix = options->b_prefix = "";
4844        else if (opt_arg(arg, '\0', "inter-hunk-context",
4845                         &options->interhunkcontext))
4846                ;
4847        else if (!strcmp(arg, "-W"))
4848                DIFF_OPT_SET(options, FUNCCONTEXT);
4849        else if (!strcmp(arg, "--function-context"))
4850                DIFF_OPT_SET(options, FUNCCONTEXT);
4851        else if (!strcmp(arg, "--no-function-context"))
4852                DIFF_OPT_CLR(options, FUNCCONTEXT);
4853        else if ((argcount = parse_long_opt("output", av, &optarg))) {
4854                char *path = prefix_filename(prefix, optarg);
4855                options->file = xfopen(path, "w");
4856                options->close_file = 1;
4857                if (options->use_color != GIT_COLOR_ALWAYS)
4858                        options->use_color = GIT_COLOR_NEVER;
4859                free(path);
4860                return argcount;
4861        } else
4862                return 0;
4863        return 1;
4864}
4865
4866int parse_rename_score(const char **cp_p)
4867{
4868        unsigned long num, scale;
4869        int ch, dot;
4870        const char *cp = *cp_p;
4871
4872        num = 0;
4873        scale = 1;
4874        dot = 0;
4875        for (;;) {
4876                ch = *cp;
4877                if ( !dot && ch == '.' ) {
4878                        scale = 1;
4879                        dot = 1;
4880                } else if ( ch == '%' ) {
4881                        scale = dot ? scale*100 : 100;
4882                        cp++;   /* % is always at the end */
4883                        break;
4884                } else if ( ch >= '0' && ch <= '9' ) {
4885                        if ( scale < 100000 ) {
4886                                scale *= 10;
4887                                num = (num*10) + (ch-'0');
4888                        }
4889                } else {
4890                        break;
4891                }
4892                cp++;
4893        }
4894        *cp_p = cp;
4895
4896        /* user says num divided by scale and we say internally that
4897         * is MAX_SCORE * num / scale.
4898         */
4899        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4900}
4901
4902static int diff_scoreopt_parse(const char *opt)
4903{
4904        int opt1, opt2, cmd;
4905
4906        if (*opt++ != '-')
4907                return -1;
4908        cmd = *opt++;
4909        if (cmd == '-') {
4910                /* convert the long-form arguments into short-form versions */
4911                if (skip_prefix(opt, "break-rewrites", &opt)) {
4912                        if (*opt == 0 || *opt++ == '=')
4913                                cmd = 'B';
4914                } else if (skip_prefix(opt, "find-copies", &opt)) {
4915                        if (*opt == 0 || *opt++ == '=')
4916                                cmd = 'C';
4917                } else if (skip_prefix(opt, "find-renames", &opt)) {
4918                        if (*opt == 0 || *opt++ == '=')
4919                                cmd = 'M';
4920                }
4921        }
4922        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4923                return -1; /* that is not a -M, -C, or -B option */
4924
4925        opt1 = parse_rename_score(&opt);
4926        if (cmd != 'B')
4927                opt2 = 0;
4928        else {
4929                if (*opt == 0)
4930                        opt2 = 0;
4931                else if (*opt != '/')
4932                        return -1; /* we expect -B80/99 or -B80 */
4933                else {
4934                        opt++;
4935                        opt2 = parse_rename_score(&opt);
4936                }
4937        }
4938        if (*opt != 0)
4939                return -1;
4940        return opt1 | (opt2 << 16);
4941}
4942
4943struct diff_queue_struct diff_queued_diff;
4944
4945void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4946{
4947        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4948        queue->queue[queue->nr++] = dp;
4949}
4950
4951struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4952                                 struct diff_filespec *one,
4953                                 struct diff_filespec *two)
4954{
4955        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4956        dp->one = one;
4957        dp->two = two;
4958        if (queue)
4959                diff_q(queue, dp);
4960        return dp;
4961}
4962
4963void diff_free_filepair(struct diff_filepair *p)
4964{
4965        free_filespec(p->one);
4966        free_filespec(p->two);
4967        free(p);
4968}
4969
4970const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4971{
4972        int abblen;
4973        const char *abbrev;
4974
4975        if (len == GIT_SHA1_HEXSZ)
4976                return oid_to_hex(oid);
4977
4978        abbrev = diff_abbrev_oid(oid, len);
4979        abblen = strlen(abbrev);
4980
4981        /*
4982         * In well-behaved cases, where the abbbreviated result is the
4983         * same as the requested length, append three dots after the
4984         * abbreviation (hence the whole logic is limited to the case
4985         * where abblen < 37); when the actual abbreviated result is a
4986         * bit longer than the requested length, we reduce the number
4987         * of dots so that they match the well-behaved ones.  However,
4988         * if the actual abbreviation is longer than the requested
4989         * length by more than three, we give up on aligning, and add
4990         * three dots anyway, to indicate that the output is not the
4991         * full object name.  Yes, this may be suboptimal, but this
4992         * appears only in "diff --raw --abbrev" output and it is not
4993         * worth the effort to change it now.  Note that this would
4994         * likely to work fine when the automatic sizing of default
4995         * abbreviation length is used--we would be fed -1 in "len" in
4996         * that case, and will end up always appending three-dots, but
4997         * the automatic sizing is supposed to give abblen that ensures
4998         * uniqueness across all objects (statistically speaking).
4999         */
5000        if (abblen < GIT_SHA1_HEXSZ - 3) {
5001                static char hex[GIT_MAX_HEXSZ + 1];
5002                if (len < abblen && abblen <= len + 2)
5003                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5004                else
5005                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5006                return hex;
5007        }
5008
5009        return oid_to_hex(oid);
5010}
5011
5012static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5013{
5014        int line_termination = opt->line_termination;
5015        int inter_name_termination = line_termination ? '\t' : '\0';
5016
5017        fprintf(opt->file, "%s", diff_line_prefix(opt));
5018        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5019                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5020                        diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5021                fprintf(opt->file, "%s ",
5022                        diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5023        }
5024        if (p->score) {
5025                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5026                        inter_name_termination);
5027        } else {
5028                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5029        }
5030
5031        if (p->status == DIFF_STATUS_COPIED ||
5032            p->status == DIFF_STATUS_RENAMED) {
5033                const char *name_a, *name_b;
5034                name_a = p->one->path;
5035                name_b = p->two->path;
5036                strip_prefix(opt->prefix_length, &name_a, &name_b);
5037                write_name_quoted(name_a, opt->file, inter_name_termination);
5038                write_name_quoted(name_b, opt->file, line_termination);
5039        } else {
5040                const char *name_a, *name_b;
5041                name_a = p->one->mode ? p->one->path : p->two->path;
5042                name_b = NULL;
5043                strip_prefix(opt->prefix_length, &name_a, &name_b);
5044                write_name_quoted(name_a, opt->file, line_termination);
5045        }
5046}
5047
5048int diff_unmodified_pair(struct diff_filepair *p)
5049{
5050        /* This function is written stricter than necessary to support
5051         * the currently implemented transformers, but the idea is to
5052         * let transformers to produce diff_filepairs any way they want,
5053         * and filter and clean them up here before producing the output.
5054         */
5055        struct diff_filespec *one = p->one, *two = p->two;
5056
5057        if (DIFF_PAIR_UNMERGED(p))
5058                return 0; /* unmerged is interesting */
5059
5060        /* deletion, addition, mode or type change
5061         * and rename are all interesting.
5062         */
5063        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5064            DIFF_PAIR_MODE_CHANGED(p) ||
5065            strcmp(one->path, two->path))
5066                return 0;
5067
5068        /* both are valid and point at the same path.  that is, we are
5069         * dealing with a change.
5070         */
5071        if (one->oid_valid && two->oid_valid &&
5072            !oidcmp(&one->oid, &two->oid) &&
5073            !one->dirty_submodule && !two->dirty_submodule)
5074                return 1; /* no change */
5075        if (!one->oid_valid && !two->oid_valid)
5076                return 1; /* both look at the same file on the filesystem. */
5077        return 0;
5078}
5079
5080static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5081{
5082        if (diff_unmodified_pair(p))
5083                return;
5084
5085        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5086            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5087                return; /* no tree diffs in patch format */
5088
5089        run_diff(p, o);
5090}
5091
5092static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5093                            struct diffstat_t *diffstat)
5094{
5095        if (diff_unmodified_pair(p))
5096                return;
5097
5098        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5099            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5100                return; /* no useful stat for tree diffs */
5101
5102        run_diffstat(p, o, diffstat);
5103}
5104
5105static void diff_flush_checkdiff(struct diff_filepair *p,
5106                struct diff_options *o)
5107{
5108        if (diff_unmodified_pair(p))
5109                return;
5110
5111        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5112            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5113                return; /* nothing to check in tree diffs */
5114
5115        run_checkdiff(p, o);
5116}
5117
5118int diff_queue_is_empty(void)
5119{
5120        struct diff_queue_struct *q = &diff_queued_diff;
5121        int i;
5122        for (i = 0; i < q->nr; i++)
5123                if (!diff_unmodified_pair(q->queue[i]))
5124                        return 0;
5125        return 1;
5126}
5127
5128#if DIFF_DEBUG
5129void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5130{
5131        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5132                x, one ? one : "",
5133                s->path,
5134                DIFF_FILE_VALID(s) ? "valid" : "invalid",
5135                s->mode,
5136                s->oid_valid ? oid_to_hex(&s->oid) : "");
5137        fprintf(stderr, "queue[%d] %s size %lu\n",
5138                x, one ? one : "",
5139                s->size);
5140}
5141
5142void diff_debug_filepair(const struct diff_filepair *p, int i)
5143{
5144        diff_debug_filespec(p->one, i, "one");
5145        diff_debug_filespec(p->two, i, "two");
5146        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5147                p->score, p->status ? p->status : '?',
5148                p->one->rename_used, p->broken_pair);
5149}
5150
5151void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5152{
5153        int i;
5154        if (msg)
5155                fprintf(stderr, "%s\n", msg);
5156        fprintf(stderr, "q->nr = %d\n", q->nr);
5157        for (i = 0; i < q->nr; i++) {
5158                struct diff_filepair *p = q->queue[i];
5159                diff_debug_filepair(p, i);
5160        }
5161}
5162#endif
5163
5164static void diff_resolve_rename_copy(void)
5165{
5166        int i;
5167        struct diff_filepair *p;
5168        struct diff_queue_struct *q = &diff_queued_diff;
5169
5170        diff_debug_queue("resolve-rename-copy", q);
5171
5172        for (i = 0; i < q->nr; i++) {
5173                p = q->queue[i];
5174                p->status = 0; /* undecided */
5175                if (DIFF_PAIR_UNMERGED(p))
5176                        p->status = DIFF_STATUS_UNMERGED;
5177                else if (!DIFF_FILE_VALID(p->one))
5178                        p->status = DIFF_STATUS_ADDED;
5179                else if (!DIFF_FILE_VALID(p->two))
5180                        p->status = DIFF_STATUS_DELETED;
5181                else if (DIFF_PAIR_TYPE_CHANGED(p))
5182                        p->status = DIFF_STATUS_TYPE_CHANGED;
5183
5184                /* from this point on, we are dealing with a pair
5185                 * whose both sides are valid and of the same type, i.e.
5186                 * either in-place edit or rename/copy edit.
5187                 */
5188                else if (DIFF_PAIR_RENAME(p)) {
5189                        /*
5190                         * A rename might have re-connected a broken
5191                         * pair up, causing the pathnames to be the
5192                         * same again. If so, that's not a rename at
5193                         * all, just a modification..
5194                         *
5195                         * Otherwise, see if this source was used for
5196                         * multiple renames, in which case we decrement
5197                         * the count, and call it a copy.
5198                         */
5199                        if (!strcmp(p->one->path, p->two->path))
5200                                p->status = DIFF_STATUS_MODIFIED;
5201                        else if (--p->one->rename_used > 0)
5202                                p->status = DIFF_STATUS_COPIED;
5203                        else
5204                                p->status = DIFF_STATUS_RENAMED;
5205                }
5206                else if (oidcmp(&p->one->oid, &p->two->oid) ||
5207                         p->one->mode != p->two->mode ||
5208                         p->one->dirty_submodule ||
5209                         p->two->dirty_submodule ||
5210                         is_null_oid(&p->one->oid))
5211                        p->status = DIFF_STATUS_MODIFIED;
5212                else {
5213                        /* This is a "no-change" entry and should not
5214                         * happen anymore, but prepare for broken callers.
5215                         */
5216                        error("feeding unmodified %s to diffcore",
5217                              p->one->path);
5218                        p->status = DIFF_STATUS_UNKNOWN;
5219                }
5220        }
5221        diff_debug_queue("resolve-rename-copy done", q);
5222}
5223
5224static int check_pair_status(struct diff_filepair *p)
5225{
5226        switch (p->status) {
5227        case DIFF_STATUS_UNKNOWN:
5228                return 0;
5229        case 0:
5230                die("internal error in diff-resolve-rename-copy");
5231        default:
5232                return 1;
5233        }
5234}
5235
5236static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5237{
5238        int fmt = opt->output_format;
5239
5240        if (fmt & DIFF_FORMAT_CHECKDIFF)
5241                diff_flush_checkdiff(p, opt);
5242        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5243                diff_flush_raw(p, opt);
5244        else if (fmt & DIFF_FORMAT_NAME) {
5245                const char *name_a, *name_b;
5246                name_a = p->two->path;
5247                name_b = NULL;
5248                strip_prefix(opt->prefix_length, &name_a, &name_b);
5249                fprintf(opt->file, "%s", diff_line_prefix(opt));
5250                write_name_quoted(name_a, opt->file, opt->line_termination);
5251        }
5252}
5253
5254static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5255{
5256        struct strbuf sb = STRBUF_INIT;
5257        if (fs->mode)
5258                strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5259        else
5260                strbuf_addf(&sb, " %s ", newdelete);
5261
5262        quote_c_style(fs->path, &sb, NULL, 0);
5263        strbuf_addch(&sb, '\n');
5264        emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5265                         sb.buf, sb.len, 0);
5266        strbuf_release(&sb);
5267}
5268
5269static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5270                int show_name)
5271{
5272        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5273                struct strbuf sb = STRBUF_INIT;
5274                strbuf_addf(&sb, " mode change %06o => %06o",
5275                            p->one->mode, p->two->mode);
5276                if (show_name) {
5277                        strbuf_addch(&sb, ' ');
5278                        quote_c_style(p->two->path, &sb, NULL, 0);
5279                }
5280                strbuf_addch(&sb, '\n');
5281                emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5282                                 sb.buf, sb.len, 0);
5283                strbuf_release(&sb);
5284        }
5285}
5286
5287static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5288                struct diff_filepair *p)
5289{
5290        struct strbuf sb = STRBUF_INIT;
5291        char *names = pprint_rename(p->one->path, p->two->path);
5292        strbuf_addf(&sb, " %s %s (%d%%)\n",
5293                        renamecopy, names, similarity_index(p));
5294        free(names);
5295        emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5296                                 sb.buf, sb.len, 0);
5297        show_mode_change(opt, p, 0);
5298        strbuf_release(&sb);
5299}
5300
5301static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5302{
5303        switch(p->status) {
5304        case DIFF_STATUS_DELETED:
5305                show_file_mode_name(opt, "delete", p->one);
5306                break;
5307        case DIFF_STATUS_ADDED:
5308                show_file_mode_name(opt, "create", p->two);
5309                break;
5310        case DIFF_STATUS_COPIED:
5311                show_rename_copy(opt, "copy", p);
5312                break;
5313        case DIFF_STATUS_RENAMED:
5314                show_rename_copy(opt, "rename", p);
5315                break;
5316        default:
5317                if (p->score) {
5318                        struct strbuf sb = STRBUF_INIT;
5319                        strbuf_addstr(&sb, " rewrite ");
5320                        quote_c_style(p->two->path, &sb, NULL, 0);
5321                        strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5322                        emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5323                                         sb.buf, sb.len, 0);
5324                        strbuf_release(&sb);
5325                }
5326                show_mode_change(opt, p, !p->score);
5327                break;
5328        }
5329}
5330
5331struct patch_id_t {
5332        git_SHA_CTX *ctx;
5333        int patchlen;
5334};
5335
5336static int remove_space(char *line, int len)
5337{
5338        int i;
5339        char *dst = line;
5340        unsigned char c;
5341
5342        for (i = 0; i < len; i++)
5343                if (!isspace((c = line[i])))
5344                        *dst++ = c;
5345
5346        return dst - line;
5347}
5348
5349static void patch_id_consume(void *priv, char *line, unsigned long len)
5350{
5351        struct patch_id_t *data = priv;
5352        int new_len;
5353
5354        /* Ignore line numbers when computing the SHA1 of the patch */
5355        if (starts_with(line, "@@ -"))
5356                return;
5357
5358        new_len = remove_space(line, len);
5359
5360        git_SHA1_Update(data->ctx, line, new_len);
5361        data->patchlen += new_len;
5362}
5363
5364static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5365{
5366        git_SHA1_Update(ctx, str, strlen(str));
5367}
5368
5369static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5370{
5371        /* large enough for 2^32 in octal */
5372        char buf[12];
5373        int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5374        git_SHA1_Update(ctx, buf, len);
5375}
5376
5377/* returns 0 upon success, and writes result into sha1 */
5378static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5379{
5380        struct diff_queue_struct *q = &diff_queued_diff;
5381        int i;
5382        git_SHA_CTX ctx;
5383        struct patch_id_t data;
5384
5385        git_SHA1_Init(&ctx);
5386        memset(&data, 0, sizeof(struct patch_id_t));
5387        data.ctx = &ctx;
5388
5389        for (i = 0; i < q->nr; i++) {
5390                xpparam_t xpp;
5391                xdemitconf_t xecfg;
5392                mmfile_t mf1, mf2;
5393                struct diff_filepair *p = q->queue[i];
5394                int len1, len2;
5395
5396                memset(&xpp, 0, sizeof(xpp));
5397                memset(&xecfg, 0, sizeof(xecfg));
5398                if (p->status == 0)
5399                        return error("internal diff status error");
5400                if (p->status == DIFF_STATUS_UNKNOWN)
5401                        continue;
5402                if (diff_unmodified_pair(p))
5403                        continue;
5404                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5405                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5406                        continue;
5407                if (DIFF_PAIR_UNMERGED(p))
5408                        continue;
5409
5410                diff_fill_oid_info(p->one);
5411                diff_fill_oid_info(p->two);
5412
5413                len1 = remove_space(p->one->path, strlen(p->one->path));
5414                len2 = remove_space(p->two->path, strlen(p->two->path));
5415                patch_id_add_string(&ctx, "diff--git");
5416                patch_id_add_string(&ctx, "a/");
5417                git_SHA1_Update(&ctx, p->one->path, len1);
5418                patch_id_add_string(&ctx, "b/");
5419                git_SHA1_Update(&ctx, p->two->path, len2);
5420
5421                if (p->one->mode == 0) {
5422                        patch_id_add_string(&ctx, "newfilemode");
5423                        patch_id_add_mode(&ctx, p->two->mode);
5424                        patch_id_add_string(&ctx, "---/dev/null");
5425                        patch_id_add_string(&ctx, "+++b/");
5426                        git_SHA1_Update(&ctx, p->two->path, len2);
5427                } else if (p->two->mode == 0) {
5428                        patch_id_add_string(&ctx, "deletedfilemode");
5429                        patch_id_add_mode(&ctx, p->one->mode);
5430                        patch_id_add_string(&ctx, "---a/");
5431                        git_SHA1_Update(&ctx, p->one->path, len1);
5432                        patch_id_add_string(&ctx, "+++/dev/null");
5433                } else {
5434                        patch_id_add_string(&ctx, "---a/");
5435                        git_SHA1_Update(&ctx, p->one->path, len1);
5436                        patch_id_add_string(&ctx, "+++b/");
5437                        git_SHA1_Update(&ctx, p->two->path, len2);
5438                }
5439
5440                if (diff_header_only)
5441                        continue;
5442
5443                if (fill_mmfile(&mf1, p->one) < 0 ||
5444                    fill_mmfile(&mf2, p->two) < 0)
5445                        return error("unable to read files to diff");
5446
5447                if (diff_filespec_is_binary(p->one) ||
5448                    diff_filespec_is_binary(p->two)) {
5449                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5450                                        GIT_SHA1_HEXSZ);
5451                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5452                                        GIT_SHA1_HEXSZ);
5453                        continue;
5454                }
5455
5456                xpp.flags = 0;
5457                xecfg.ctxlen = 3;
5458                xecfg.flags = 0;
5459                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5460                                  &xpp, &xecfg))
5461                        return error("unable to generate patch-id diff for %s",
5462                                     p->one->path);
5463        }
5464
5465        git_SHA1_Final(oid->hash, &ctx);
5466        return 0;
5467}
5468
5469int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5470{
5471        struct diff_queue_struct *q = &diff_queued_diff;
5472        int i;
5473        int result = diff_get_patch_id(options, oid, diff_header_only);
5474
5475        for (i = 0; i < q->nr; i++)
5476                diff_free_filepair(q->queue[i]);
5477
5478        free(q->queue);
5479        DIFF_QUEUE_CLEAR(q);
5480
5481        return result;
5482}
5483
5484static int is_summary_empty(const struct diff_queue_struct *q)
5485{
5486        int i;
5487
5488        for (i = 0; i < q->nr; i++) {
5489                const struct diff_filepair *p = q->queue[i];
5490
5491                switch (p->status) {
5492                case DIFF_STATUS_DELETED:
5493                case DIFF_STATUS_ADDED:
5494                case DIFF_STATUS_COPIED:
5495                case DIFF_STATUS_RENAMED:
5496                        return 0;
5497                default:
5498                        if (p->score)
5499                                return 0;
5500                        if (p->one->mode && p->two->mode &&
5501                            p->one->mode != p->two->mode)
5502                                return 0;
5503                        break;
5504                }
5505        }
5506        return 1;
5507}
5508
5509static const char rename_limit_warning[] =
5510N_("inexact rename detection was skipped due to too many files.");
5511
5512static const char degrade_cc_to_c_warning[] =
5513N_("only found copies from modified paths due to too many files.");
5514
5515static const char rename_limit_advice[] =
5516N_("you may want to set your %s variable to at least "
5517   "%d and retry the command.");
5518
5519void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5520{
5521        if (degraded_cc)
5522                warning(_(degrade_cc_to_c_warning));
5523        else if (needed)
5524                warning(_(rename_limit_warning));
5525        else
5526                return;
5527        if (0 < needed && needed < 32767)
5528                warning(_(rename_limit_advice), varname, needed);
5529}
5530
5531static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5532{
5533        int i;
5534        static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5535        struct diff_queue_struct *q = &diff_queued_diff;
5536
5537        if (WSEH_NEW & WS_RULE_MASK)
5538                die("BUG: WS rules bit mask overlaps with diff symbol flags");
5539
5540        if (o->color_moved)
5541                o->emitted_symbols = &esm;
5542
5543        for (i = 0; i < q->nr; i++) {
5544                struct diff_filepair *p = q->queue[i];
5545                if (check_pair_status(p))
5546                        diff_flush_patch(p, o);
5547        }
5548
5549        if (o->emitted_symbols) {
5550                if (o->color_moved) {
5551                        struct hashmap add_lines, del_lines;
5552
5553                        hashmap_init(&del_lines,
5554                                     (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5555                        hashmap_init(&add_lines,
5556                                     (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5557
5558                        add_lines_to_move_detection(o, &add_lines, &del_lines);
5559                        mark_color_as_moved(o, &add_lines, &del_lines);
5560                        if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5561                                dim_moved_lines(o);
5562
5563                        hashmap_free(&add_lines, 0);
5564                        hashmap_free(&del_lines, 0);
5565                }
5566
5567                for (i = 0; i < esm.nr; i++)
5568                        emit_diff_symbol_from_struct(o, &esm.buf[i]);
5569
5570                for (i = 0; i < esm.nr; i++)
5571                        free((void *)esm.buf[i].line);
5572        }
5573        esm.nr = 0;
5574}
5575
5576void diff_flush(struct diff_options *options)
5577{
5578        struct diff_queue_struct *q = &diff_queued_diff;
5579        int i, output_format = options->output_format;
5580        int separator = 0;
5581        int dirstat_by_line = 0;
5582
5583        /*
5584         * Order: raw, stat, summary, patch
5585         * or:    name/name-status/checkdiff (other bits clear)
5586         */
5587        if (!q->nr)
5588                goto free_queue;
5589
5590        if (output_format & (DIFF_FORMAT_RAW |
5591                             DIFF_FORMAT_NAME |
5592                             DIFF_FORMAT_NAME_STATUS |
5593                             DIFF_FORMAT_CHECKDIFF)) {
5594                for (i = 0; i < q->nr; i++) {
5595                        struct diff_filepair *p = q->queue[i];
5596                        if (check_pair_status(p))
5597                                flush_one_pair(p, options);
5598                }
5599                separator++;
5600        }
5601
5602        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
5603                dirstat_by_line = 1;
5604
5605        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5606            dirstat_by_line) {
5607                struct diffstat_t diffstat;
5608
5609                memset(&diffstat, 0, sizeof(struct diffstat_t));
5610                for (i = 0; i < q->nr; i++) {
5611                        struct diff_filepair *p = q->queue[i];
5612                        if (check_pair_status(p))
5613                                diff_flush_stat(p, options, &diffstat);
5614                }
5615                if (output_format & DIFF_FORMAT_NUMSTAT)
5616                        show_numstat(&diffstat, options);
5617                if (output_format & DIFF_FORMAT_DIFFSTAT)
5618                        show_stats(&diffstat, options);
5619                if (output_format & DIFF_FORMAT_SHORTSTAT)
5620                        show_shortstats(&diffstat, options);
5621                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5622                        show_dirstat_by_line(&diffstat, options);
5623                free_diffstat_info(&diffstat);
5624                separator++;
5625        }
5626        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5627                show_dirstat(options);
5628
5629        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5630                for (i = 0; i < q->nr; i++) {
5631                        diff_summary(options, q->queue[i]);
5632                }
5633                separator++;
5634        }
5635
5636        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5637            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
5638            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
5639                /*
5640                 * run diff_flush_patch for the exit status. setting
5641                 * options->file to /dev/null should be safe, because we
5642                 * aren't supposed to produce any output anyway.
5643                 */
5644                if (options->close_file)
5645                        fclose(options->file);
5646                options->file = xfopen("/dev/null", "w");
5647                options->close_file = 1;
5648                options->color_moved = 0;
5649                for (i = 0; i < q->nr; i++) {
5650                        struct diff_filepair *p = q->queue[i];
5651                        if (check_pair_status(p))
5652                                diff_flush_patch(p, options);
5653                        if (options->found_changes)
5654                                break;
5655                }
5656        }
5657
5658        if (output_format & DIFF_FORMAT_PATCH) {
5659                if (separator) {
5660                        emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5661                        if (options->stat_sep)
5662                                /* attach patch instead of inline */
5663                                emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5664                                                 NULL, 0, 0);
5665                }
5666
5667                diff_flush_patch_all_file_pairs(options);
5668        }
5669
5670        if (output_format & DIFF_FORMAT_CALLBACK)
5671                options->format_callback(q, options, options->format_callback_data);
5672
5673        for (i = 0; i < q->nr; i++)
5674                diff_free_filepair(q->queue[i]);
5675free_queue:
5676        free(q->queue);
5677        DIFF_QUEUE_CLEAR(q);
5678        if (options->close_file)
5679                fclose(options->file);
5680
5681        /*
5682         * Report the content-level differences with HAS_CHANGES;
5683         * diff_addremove/diff_change does not set the bit when
5684         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5685         */
5686        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
5687                if (options->found_changes)
5688                        DIFF_OPT_SET(options, HAS_CHANGES);
5689                else
5690                        DIFF_OPT_CLR(options, HAS_CHANGES);
5691        }
5692}
5693
5694static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5695{
5696        return (((p->status == DIFF_STATUS_MODIFIED) &&
5697                 ((p->score &&
5698                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5699                  (!p->score &&
5700                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5701                ((p->status != DIFF_STATUS_MODIFIED) &&
5702                 filter_bit_tst(p->status, options)));
5703}
5704
5705static void diffcore_apply_filter(struct diff_options *options)
5706{
5707        int i;
5708        struct diff_queue_struct *q = &diff_queued_diff;
5709        struct diff_queue_struct outq;
5710
5711        DIFF_QUEUE_CLEAR(&outq);
5712
5713        if (!options->filter)
5714                return;
5715
5716        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5717                int found;
5718                for (i = found = 0; !found && i < q->nr; i++) {
5719                        if (match_filter(options, q->queue[i]))
5720                                found++;
5721                }
5722                if (found)
5723                        return;
5724
5725                /* otherwise we will clear the whole queue
5726                 * by copying the empty outq at the end of this
5727                 * function, but first clear the current entries
5728                 * in the queue.
5729                 */
5730                for (i = 0; i < q->nr; i++)
5731                        diff_free_filepair(q->queue[i]);
5732        }
5733        else {
5734                /* Only the matching ones */
5735                for (i = 0; i < q->nr; i++) {
5736                        struct diff_filepair *p = q->queue[i];
5737                        if (match_filter(options, p))
5738                                diff_q(&outq, p);
5739                        else
5740                                diff_free_filepair(p);
5741                }
5742        }
5743        free(q->queue);
5744        *q = outq;
5745}
5746
5747/* Check whether two filespecs with the same mode and size are identical */
5748static int diff_filespec_is_identical(struct diff_filespec *one,
5749                                      struct diff_filespec *two)
5750{
5751        if (S_ISGITLINK(one->mode))
5752                return 0;
5753        if (diff_populate_filespec(one, 0))
5754                return 0;
5755        if (diff_populate_filespec(two, 0))
5756                return 0;
5757        return !memcmp(one->data, two->data, one->size);
5758}
5759
5760static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5761{
5762        if (p->done_skip_stat_unmatch)
5763                return p->skip_stat_unmatch_result;
5764
5765        p->done_skip_stat_unmatch = 1;
5766        p->skip_stat_unmatch_result = 0;
5767        /*
5768         * 1. Entries that come from stat info dirtiness
5769         *    always have both sides (iow, not create/delete),
5770         *    one side of the object name is unknown, with
5771         *    the same mode and size.  Keep the ones that
5772         *    do not match these criteria.  They have real
5773         *    differences.
5774         *
5775         * 2. At this point, the file is known to be modified,
5776         *    with the same mode and size, and the object
5777         *    name of one side is unknown.  Need to inspect
5778         *    the identical contents.
5779         */
5780        if (!DIFF_FILE_VALID(p->one) || /* (1) */
5781            !DIFF_FILE_VALID(p->two) ||
5782            (p->one->oid_valid && p->two->oid_valid) ||
5783            (p->one->mode != p->two->mode) ||
5784            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5785            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5786            (p->one->size != p->two->size) ||
5787            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5788                p->skip_stat_unmatch_result = 1;
5789        return p->skip_stat_unmatch_result;
5790}
5791
5792static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5793{
5794        int i;
5795        struct diff_queue_struct *q = &diff_queued_diff;
5796        struct diff_queue_struct outq;
5797        DIFF_QUEUE_CLEAR(&outq);
5798
5799        for (i = 0; i < q->nr; i++) {
5800                struct diff_filepair *p = q->queue[i];
5801
5802                if (diff_filespec_check_stat_unmatch(p))
5803                        diff_q(&outq, p);
5804                else {
5805                        /*
5806                         * The caller can subtract 1 from skip_stat_unmatch
5807                         * to determine how many paths were dirty only
5808                         * due to stat info mismatch.
5809                         */
5810                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5811                                diffopt->skip_stat_unmatch++;
5812                        diff_free_filepair(p);
5813                }
5814        }
5815        free(q->queue);
5816        *q = outq;
5817}
5818
5819static int diffnamecmp(const void *a_, const void *b_)
5820{
5821        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5822        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5823        const char *name_a, *name_b;
5824
5825        name_a = a->one ? a->one->path : a->two->path;
5826        name_b = b->one ? b->one->path : b->two->path;
5827        return strcmp(name_a, name_b);
5828}
5829
5830void diffcore_fix_diff_index(struct diff_options *options)
5831{
5832        struct diff_queue_struct *q = &diff_queued_diff;
5833        QSORT(q->queue, q->nr, diffnamecmp);
5834}
5835
5836void diffcore_std(struct diff_options *options)
5837{
5838        /* NOTE please keep the following in sync with diff_tree_combined() */
5839        if (options->skip_stat_unmatch)
5840                diffcore_skip_stat_unmatch(options);
5841        if (!options->found_follow) {
5842                /* See try_to_follow_renames() in tree-diff.c */
5843                if (options->break_opt != -1)
5844                        diffcore_break(options->break_opt);
5845                if (options->detect_rename)
5846                        diffcore_rename(options);
5847                if (options->break_opt != -1)
5848                        diffcore_merge_broken();
5849        }
5850        if (options->pickaxe)
5851                diffcore_pickaxe(options);
5852        if (options->orderfile)
5853                diffcore_order(options->orderfile);
5854        if (!options->found_follow)
5855                /* See try_to_follow_renames() in tree-diff.c */
5856                diff_resolve_rename_copy();
5857        diffcore_apply_filter(options);
5858
5859        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5860                DIFF_OPT_SET(options, HAS_CHANGES);
5861        else
5862                DIFF_OPT_CLR(options, HAS_CHANGES);
5863
5864        options->found_follow = 0;
5865}
5866
5867int diff_result_code(struct diff_options *opt, int status)
5868{
5869        int result = 0;
5870
5871        diff_warn_rename_limit("diff.renameLimit",
5872                               opt->needed_rename_limit,
5873                               opt->degraded_cc_to_c);
5874        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5875            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5876                return status;
5877        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5878            DIFF_OPT_TST(opt, HAS_CHANGES))
5879                result |= 01;
5880        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5881            DIFF_OPT_TST(opt, CHECK_FAILED))
5882                result |= 02;
5883        return result;
5884}
5885
5886int diff_can_quit_early(struct diff_options *opt)
5887{
5888        return (DIFF_OPT_TST(opt, QUICK) &&
5889                !opt->filter &&
5890                DIFF_OPT_TST(opt, HAS_CHANGES));
5891}
5892
5893/*
5894 * Shall changes to this submodule be ignored?
5895 *
5896 * Submodule changes can be configured to be ignored separately for each path,
5897 * but that configuration can be overridden from the command line.
5898 */
5899static int is_submodule_ignored(const char *path, struct diff_options *options)
5900{
5901        int ignored = 0;
5902        unsigned orig_flags = options->flags;
5903        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5904                set_diffopt_flags_from_submodule_config(options, path);
5905        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5906                ignored = 1;
5907        options->flags = orig_flags;
5908        return ignored;
5909}
5910
5911void diff_addremove(struct diff_options *options,
5912                    int addremove, unsigned mode,
5913                    const struct object_id *oid,
5914                    int oid_valid,
5915                    const char *concatpath, unsigned dirty_submodule)
5916{
5917        struct diff_filespec *one, *two;
5918
5919        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5920                return;
5921
5922        /* This may look odd, but it is a preparation for
5923         * feeding "there are unchanged files which should
5924         * not produce diffs, but when you are doing copy
5925         * detection you would need them, so here they are"
5926         * entries to the diff-core.  They will be prefixed
5927         * with something like '=' or '*' (I haven't decided
5928         * which but should not make any difference).
5929         * Feeding the same new and old to diff_change()
5930         * also has the same effect.
5931         * Before the final output happens, they are pruned after
5932         * merged into rename/copy pairs as appropriate.
5933         */
5934        if (DIFF_OPT_TST(options, REVERSE_DIFF))
5935                addremove = (addremove == '+' ? '-' :
5936                             addremove == '-' ? '+' : addremove);
5937
5938        if (options->prefix &&
5939            strncmp(concatpath, options->prefix, options->prefix_length))
5940                return;
5941
5942        one = alloc_filespec(concatpath);
5943        two = alloc_filespec(concatpath);
5944
5945        if (addremove != '+')
5946                fill_filespec(one, oid, oid_valid, mode);
5947        if (addremove != '-') {
5948                fill_filespec(two, oid, oid_valid, mode);
5949                two->dirty_submodule = dirty_submodule;
5950        }
5951
5952        diff_queue(&diff_queued_diff, one, two);
5953        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5954                DIFF_OPT_SET(options, HAS_CHANGES);
5955}
5956
5957void diff_change(struct diff_options *options,
5958                 unsigned old_mode, unsigned new_mode,
5959                 const struct object_id *old_oid,
5960                 const struct object_id *new_oid,
5961                 int old_oid_valid, int new_oid_valid,
5962                 const char *concatpath,
5963                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5964{
5965        struct diff_filespec *one, *two;
5966        struct diff_filepair *p;
5967
5968        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5969            is_submodule_ignored(concatpath, options))
5970                return;
5971
5972        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5973                SWAP(old_mode, new_mode);
5974                SWAP(old_oid, new_oid);
5975                SWAP(old_oid_valid, new_oid_valid);
5976                SWAP(old_dirty_submodule, new_dirty_submodule);
5977        }
5978
5979        if (options->prefix &&
5980            strncmp(concatpath, options->prefix, options->prefix_length))
5981                return;
5982
5983        one = alloc_filespec(concatpath);
5984        two = alloc_filespec(concatpath);
5985        fill_filespec(one, old_oid, old_oid_valid, old_mode);
5986        fill_filespec(two, new_oid, new_oid_valid, new_mode);
5987        one->dirty_submodule = old_dirty_submodule;
5988        two->dirty_submodule = new_dirty_submodule;
5989        p = diff_queue(&diff_queued_diff, one, two);
5990
5991        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5992                return;
5993
5994        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5995            !diff_filespec_check_stat_unmatch(p))
5996                return;
5997
5998        DIFF_OPT_SET(options, HAS_CHANGES);
5999}
6000
6001struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6002{
6003        struct diff_filepair *pair;
6004        struct diff_filespec *one, *two;
6005
6006        if (options->prefix &&
6007            strncmp(path, options->prefix, options->prefix_length))
6008                return NULL;
6009
6010        one = alloc_filespec(path);
6011        two = alloc_filespec(path);
6012        pair = diff_queue(&diff_queued_diff, one, two);
6013        pair->is_unmerged = 1;
6014        return pair;
6015}
6016
6017static char *run_textconv(const char *pgm, struct diff_filespec *spec,
6018                size_t *outsize)
6019{
6020        struct diff_tempfile *temp;
6021        const char *argv[3];
6022        const char **arg = argv;
6023        struct child_process child = CHILD_PROCESS_INIT;
6024        struct strbuf buf = STRBUF_INIT;
6025        int err = 0;
6026
6027        temp = prepare_temp_file(spec->path, spec);
6028        *arg++ = pgm;
6029        *arg++ = temp->name;
6030        *arg = NULL;
6031
6032        child.use_shell = 1;
6033        child.argv = argv;
6034        child.out = -1;
6035        if (start_command(&child)) {
6036                remove_tempfile();
6037                return NULL;
6038        }
6039
6040        if (strbuf_read(&buf, child.out, 0) < 0)
6041                err = error("error reading from textconv command '%s'", pgm);
6042        close(child.out);
6043
6044        if (finish_command(&child) || err) {
6045                strbuf_release(&buf);
6046                remove_tempfile();
6047                return NULL;
6048        }
6049        remove_tempfile();
6050
6051        return strbuf_detach(&buf, outsize);
6052}
6053
6054size_t fill_textconv(struct userdiff_driver *driver,
6055                     struct diff_filespec *df,
6056                     char **outbuf)
6057{
6058        size_t size;
6059
6060        if (!driver) {
6061                if (!DIFF_FILE_VALID(df)) {
6062                        *outbuf = "";
6063                        return 0;
6064                }
6065                if (diff_populate_filespec(df, 0))
6066                        die("unable to read files to diff");
6067                *outbuf = df->data;
6068                return df->size;
6069        }
6070
6071        if (!driver->textconv)
6072                die("BUG: fill_textconv called with non-textconv driver");
6073
6074        if (driver->textconv_cache && df->oid_valid) {
6075                *outbuf = notes_cache_get(driver->textconv_cache,
6076                                          &df->oid,
6077                                          &size);
6078                if (*outbuf)
6079                        return size;
6080        }
6081
6082        *outbuf = run_textconv(driver->textconv, df, &size);
6083        if (!*outbuf)
6084                die("unable to read files to diff");
6085
6086        if (driver->textconv_cache && df->oid_valid) {
6087                /* ignore errors, as we might be in a readonly repository */
6088                notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6089                                size);
6090                /*
6091                 * we could save up changes and flush them all at the end,
6092                 * but we would need an extra call after all diffing is done.
6093                 * Since generating a cache entry is the slow path anyway,
6094                 * this extra overhead probably isn't a big deal.
6095                 */
6096                notes_cache_write(driver->textconv_cache);
6097        }
6098
6099        return size;
6100}
6101
6102int textconv_object(const char *path,
6103                    unsigned mode,
6104                    const struct object_id *oid,
6105                    int oid_valid,
6106                    char **buf,
6107                    unsigned long *buf_size)
6108{
6109        struct diff_filespec *df;
6110        struct userdiff_driver *textconv;
6111
6112        df = alloc_filespec(path);
6113        fill_filespec(df, oid, oid_valid, mode);
6114        textconv = get_textconv(df);
6115        if (!textconv) {
6116                free_filespec(df);
6117                return 0;
6118        }
6119
6120        *buf_size = fill_textconv(textconv, df, buf);
6121        free_filespec(df);
6122        return 1;
6123}
6124
6125void setup_diff_pager(struct diff_options *opt)
6126{
6127        /*
6128         * If the user asked for our exit code, then either they want --quiet
6129         * or --exit-code. We should definitely not bother with a pager in the
6130         * former case, as we will generate no output. Since we still properly
6131         * report our exit code even when a pager is run, we _could_ run a
6132         * pager with --exit-code. But since we have not done so historically,
6133         * and because it is easy to find people oneline advising "git diff
6134         * --exit-code" in hooks and other scripts, we do not do so.
6135         */
6136        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
6137            check_pager_config("diff") != 0)
6138                setup_pager();
6139}