diff.con commit wildmatch test: mark test as EXPENSIVE_ON_WINDOWS (8725923)
   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 moved_entry_cmp(const struct diff_options *diffopt,
 711                           const struct moved_entry *a,
 712                           const struct moved_entry *b,
 713                           const void *keydata)
 714{
 715        return !xdiff_compare_lines(a->es->line, a->es->len,
 716                                    b->es->line, b->es->len,
 717                                    diffopt->xdl_opts);
 718}
 719
 720static struct moved_entry *prepare_entry(struct diff_options *o,
 721                                         int line_no)
 722{
 723        struct moved_entry *ret = xmalloc(sizeof(*ret));
 724        struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 725
 726        ret->ent.hash = xdiff_hash_string(l->line, l->len, o->xdl_opts);
 727        ret->es = l;
 728        ret->next_line = NULL;
 729
 730        return ret;
 731}
 732
 733static void add_lines_to_move_detection(struct diff_options *o,
 734                                        struct hashmap *add_lines,
 735                                        struct hashmap *del_lines)
 736{
 737        struct moved_entry *prev_line = NULL;
 738
 739        int n;
 740        for (n = 0; n < o->emitted_symbols->nr; n++) {
 741                struct hashmap *hm;
 742                struct moved_entry *key;
 743
 744                switch (o->emitted_symbols->buf[n].s) {
 745                case DIFF_SYMBOL_PLUS:
 746                        hm = add_lines;
 747                        break;
 748                case DIFF_SYMBOL_MINUS:
 749                        hm = del_lines;
 750                        break;
 751                default:
 752                        prev_line = NULL;
 753                        continue;
 754                }
 755
 756                key = prepare_entry(o, n);
 757                if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 758                        prev_line->next_line = key;
 759
 760                hashmap_add(hm, key);
 761                prev_line = key;
 762        }
 763}
 764
 765static int shrink_potential_moved_blocks(struct moved_entry **pmb,
 766                                         int pmb_nr)
 767{
 768        int lp, rp;
 769
 770        /* Shrink the set of potential block to the remaining running */
 771        for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
 772                while (lp < pmb_nr && pmb[lp])
 773                        lp++;
 774                /* lp points at the first NULL now */
 775
 776                while (rp > -1 && !pmb[rp])
 777                        rp--;
 778                /* rp points at the last non-NULL */
 779
 780                if (lp < pmb_nr && rp > -1 && lp < rp) {
 781                        pmb[lp] = pmb[rp];
 782                        pmb[rp] = NULL;
 783                        rp--;
 784                        lp++;
 785                }
 786        }
 787
 788        /* Remember the number of running sets */
 789        return rp + 1;
 790}
 791
 792/*
 793 * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
 794 *
 795 * Otherwise, if the last block has fewer alphanumeric characters than
 796 * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
 797 * that block.
 798 *
 799 * The last block consists of the (n - block_length)'th line up to but not
 800 * including the nth line.
 801 *
 802 * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
 803 * Think of a way to unify them.
 804 */
 805static void adjust_last_block(struct diff_options *o, int n, int block_length)
 806{
 807        int i, alnum_count = 0;
 808        if (o->color_moved == COLOR_MOVED_PLAIN)
 809                return;
 810        for (i = 1; i < block_length + 1; i++) {
 811                const char *c = o->emitted_symbols->buf[n - i].line;
 812                for (; *c; c++) {
 813                        if (!isalnum(*c))
 814                                continue;
 815                        alnum_count++;
 816                        if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
 817                                return;
 818                }
 819        }
 820        for (i = 1; i < block_length + 1; i++)
 821                o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
 822}
 823
 824/* Find blocks of moved code, delegate actual coloring decision to helper */
 825static void mark_color_as_moved(struct diff_options *o,
 826                                struct hashmap *add_lines,
 827                                struct hashmap *del_lines)
 828{
 829        struct moved_entry **pmb = NULL; /* potentially moved blocks */
 830        int pmb_nr = 0, pmb_alloc = 0;
 831        int n, flipped_block = 1, block_length = 0;
 832
 833
 834        for (n = 0; n < o->emitted_symbols->nr; n++) {
 835                struct hashmap *hm = NULL;
 836                struct moved_entry *key;
 837                struct moved_entry *match = NULL;
 838                struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 839                int i;
 840
 841                switch (l->s) {
 842                case DIFF_SYMBOL_PLUS:
 843                        hm = del_lines;
 844                        key = prepare_entry(o, n);
 845                        match = hashmap_get(hm, key, o);
 846                        free(key);
 847                        break;
 848                case DIFF_SYMBOL_MINUS:
 849                        hm = add_lines;
 850                        key = prepare_entry(o, n);
 851                        match = hashmap_get(hm, key, o);
 852                        free(key);
 853                        break;
 854                default:
 855                        flipped_block = 1;
 856                }
 857
 858                if (!match) {
 859                        adjust_last_block(o, n, block_length);
 860                        pmb_nr = 0;
 861                        block_length = 0;
 862                        continue;
 863                }
 864
 865                l->flags |= DIFF_SYMBOL_MOVED_LINE;
 866
 867                if (o->color_moved == COLOR_MOVED_PLAIN)
 868                        continue;
 869
 870                /* Check any potential block runs, advance each or nullify */
 871                for (i = 0; i < pmb_nr; i++) {
 872                        struct moved_entry *p = pmb[i];
 873                        struct moved_entry *pnext = (p && p->next_line) ?
 874                                        p->next_line : NULL;
 875                        if (pnext && !hm->cmpfn(o, pnext, match, NULL)) {
 876                                pmb[i] = p->next_line;
 877                        } else {
 878                                pmb[i] = NULL;
 879                        }
 880                }
 881
 882                pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
 883
 884                if (pmb_nr == 0) {
 885                        /*
 886                         * The current line is the start of a new block.
 887                         * Setup the set of potential blocks.
 888                         */
 889                        for (; match; match = hashmap_get_next(hm, match)) {
 890                                ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
 891                                pmb[pmb_nr++] = match;
 892                        }
 893
 894                        flipped_block = (flipped_block + 1) % 2;
 895
 896                        adjust_last_block(o, n, block_length);
 897                        block_length = 0;
 898                }
 899
 900                block_length++;
 901
 902                if (flipped_block)
 903                        l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
 904        }
 905        adjust_last_block(o, n, block_length);
 906
 907        free(pmb);
 908}
 909
 910#define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
 911  (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
 912static void dim_moved_lines(struct diff_options *o)
 913{
 914        int n;
 915        for (n = 0; n < o->emitted_symbols->nr; n++) {
 916                struct emitted_diff_symbol *prev = (n != 0) ?
 917                                &o->emitted_symbols->buf[n - 1] : NULL;
 918                struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 919                struct emitted_diff_symbol *next =
 920                                (n < o->emitted_symbols->nr - 1) ?
 921                                &o->emitted_symbols->buf[n + 1] : NULL;
 922
 923                /* Not a plus or minus line? */
 924                if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
 925                        continue;
 926
 927                /* Not a moved line? */
 928                if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
 929                        continue;
 930
 931                /*
 932                 * If prev or next are not a plus or minus line,
 933                 * pretend they don't exist
 934                 */
 935                if (prev && prev->s != DIFF_SYMBOL_PLUS &&
 936                            prev->s != DIFF_SYMBOL_MINUS)
 937                        prev = NULL;
 938                if (next && next->s != DIFF_SYMBOL_PLUS &&
 939                            next->s != DIFF_SYMBOL_MINUS)
 940                        next = NULL;
 941
 942                /* Inside a block? */
 943                if ((prev &&
 944                    (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
 945                    (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
 946                    (next &&
 947                    (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
 948                    (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
 949                        l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
 950                        continue;
 951                }
 952
 953                /* Check if we are at an interesting bound: */
 954                if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
 955                    (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
 956                       (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
 957                        continue;
 958                if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
 959                    (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
 960                       (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
 961                        continue;
 962
 963                /*
 964                 * The boundary to prev and next are not interesting,
 965                 * so this line is not interesting as a whole
 966                 */
 967                l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
 968        }
 969}
 970
 971static void emit_line_ws_markup(struct diff_options *o,
 972                                const char *set, const char *reset,
 973                                const char *line, int len, char sign,
 974                                unsigned ws_rule, int blank_at_eof)
 975{
 976        const char *ws = NULL;
 977
 978        if (o->ws_error_highlight & ws_rule) {
 979                ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 980                if (!*ws)
 981                        ws = NULL;
 982        }
 983
 984        if (!ws)
 985                emit_line_0(o, set, reset, sign, line, len);
 986        else if (blank_at_eof)
 987                /* Blank line at EOF - paint '+' as well */
 988                emit_line_0(o, ws, reset, sign, line, len);
 989        else {
 990                /* Emit just the prefix, then the rest. */
 991                emit_line_0(o, set, reset, sign, "", 0);
 992                ws_check_emit(line, len, ws_rule,
 993                              o->file, set, reset, ws);
 994        }
 995}
 996
 997static void emit_diff_symbol_from_struct(struct diff_options *o,
 998                                         struct emitted_diff_symbol *eds)
 999{
1000        static const char *nneof = " No newline at end of file\n";
1001        const char *context, *reset, *set, *meta, *fraginfo;
1002        struct strbuf sb = STRBUF_INIT;
1003
1004        enum diff_symbol s = eds->s;
1005        const char *line = eds->line;
1006        int len = eds->len;
1007        unsigned flags = eds->flags;
1008
1009        switch (s) {
1010        case DIFF_SYMBOL_NO_LF_EOF:
1011                context = diff_get_color_opt(o, DIFF_CONTEXT);
1012                reset = diff_get_color_opt(o, DIFF_RESET);
1013                putc('\n', o->file);
1014                emit_line_0(o, context, reset, '\\',
1015                            nneof, strlen(nneof));
1016                break;
1017        case DIFF_SYMBOL_SUBMODULE_HEADER:
1018        case DIFF_SYMBOL_SUBMODULE_ERROR:
1019        case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1020        case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1021        case DIFF_SYMBOL_SUMMARY:
1022        case DIFF_SYMBOL_STATS_LINE:
1023        case DIFF_SYMBOL_BINARY_DIFF_BODY:
1024        case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1025                emit_line(o, "", "", line, len);
1026                break;
1027        case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1028        case DIFF_SYMBOL_CONTEXT_MARKER:
1029                context = diff_get_color_opt(o, DIFF_CONTEXT);
1030                reset = diff_get_color_opt(o, DIFF_RESET);
1031                emit_line(o, context, reset, line, len);
1032                break;
1033        case DIFF_SYMBOL_SEPARATOR:
1034                fprintf(o->file, "%s%c",
1035                        diff_line_prefix(o),
1036                        o->line_termination);
1037                break;
1038        case DIFF_SYMBOL_CONTEXT:
1039                set = diff_get_color_opt(o, DIFF_CONTEXT);
1040                reset = diff_get_color_opt(o, DIFF_RESET);
1041                emit_line_ws_markup(o, set, reset, line, len, ' ',
1042                                    flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1043                break;
1044        case DIFF_SYMBOL_PLUS:
1045                switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1046                                 DIFF_SYMBOL_MOVED_LINE_ALT |
1047                                 DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1048                case DIFF_SYMBOL_MOVED_LINE |
1049                     DIFF_SYMBOL_MOVED_LINE_ALT |
1050                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1051                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1052                        break;
1053                case DIFF_SYMBOL_MOVED_LINE |
1054                     DIFF_SYMBOL_MOVED_LINE_ALT:
1055                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1056                        break;
1057                case DIFF_SYMBOL_MOVED_LINE |
1058                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1059                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1060                        break;
1061                case DIFF_SYMBOL_MOVED_LINE:
1062                        set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1063                        break;
1064                default:
1065                        set = diff_get_color_opt(o, DIFF_FILE_NEW);
1066                }
1067                reset = diff_get_color_opt(o, DIFF_RESET);
1068                emit_line_ws_markup(o, set, reset, line, len, '+',
1069                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1070                                    flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1071                break;
1072        case DIFF_SYMBOL_MINUS:
1073                switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1074                                 DIFF_SYMBOL_MOVED_LINE_ALT |
1075                                 DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1076                case DIFF_SYMBOL_MOVED_LINE |
1077                     DIFF_SYMBOL_MOVED_LINE_ALT |
1078                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1079                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1080                        break;
1081                case DIFF_SYMBOL_MOVED_LINE |
1082                     DIFF_SYMBOL_MOVED_LINE_ALT:
1083                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1084                        break;
1085                case DIFF_SYMBOL_MOVED_LINE |
1086                     DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1087                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1088                        break;
1089                case DIFF_SYMBOL_MOVED_LINE:
1090                        set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1091                        break;
1092                default:
1093                        set = diff_get_color_opt(o, DIFF_FILE_OLD);
1094                }
1095                reset = diff_get_color_opt(o, DIFF_RESET);
1096                emit_line_ws_markup(o, set, reset, line, len, '-',
1097                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1098                break;
1099        case DIFF_SYMBOL_WORDS_PORCELAIN:
1100                context = diff_get_color_opt(o, DIFF_CONTEXT);
1101                reset = diff_get_color_opt(o, DIFF_RESET);
1102                emit_line(o, context, reset, line, len);
1103                fputs("~\n", o->file);
1104                break;
1105        case DIFF_SYMBOL_WORDS:
1106                context = diff_get_color_opt(o, DIFF_CONTEXT);
1107                reset = diff_get_color_opt(o, DIFF_RESET);
1108                /*
1109                 * Skip the prefix character, if any.  With
1110                 * diff_suppress_blank_empty, there may be
1111                 * none.
1112                 */
1113                if (line[0] != '\n') {
1114                        line++;
1115                        len--;
1116                }
1117                emit_line(o, context, reset, line, len);
1118                break;
1119        case DIFF_SYMBOL_FILEPAIR_PLUS:
1120                meta = diff_get_color_opt(o, DIFF_METAINFO);
1121                reset = diff_get_color_opt(o, DIFF_RESET);
1122                fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1123                        line, reset,
1124                        strchr(line, ' ') ? "\t" : "");
1125                break;
1126        case DIFF_SYMBOL_FILEPAIR_MINUS:
1127                meta = diff_get_color_opt(o, DIFF_METAINFO);
1128                reset = diff_get_color_opt(o, DIFF_RESET);
1129                fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1130                        line, reset,
1131                        strchr(line, ' ') ? "\t" : "");
1132                break;
1133        case DIFF_SYMBOL_BINARY_FILES:
1134        case DIFF_SYMBOL_HEADER:
1135                fprintf(o->file, "%s", line);
1136                break;
1137        case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1138                fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1139                break;
1140        case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1141                fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1142                break;
1143        case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1144                fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1145                break;
1146        case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1147                fputs(diff_line_prefix(o), o->file);
1148                fputc('\n', o->file);
1149                break;
1150        case DIFF_SYMBOL_REWRITE_DIFF:
1151                fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1152                reset = diff_get_color_opt(o, DIFF_RESET);
1153                emit_line(o, fraginfo, reset, line, len);
1154                break;
1155        case DIFF_SYMBOL_SUBMODULE_ADD:
1156                set = diff_get_color_opt(o, DIFF_FILE_NEW);
1157                reset = diff_get_color_opt(o, DIFF_RESET);
1158                emit_line(o, set, reset, line, len);
1159                break;
1160        case DIFF_SYMBOL_SUBMODULE_DEL:
1161                set = diff_get_color_opt(o, DIFF_FILE_OLD);
1162                reset = diff_get_color_opt(o, DIFF_RESET);
1163                emit_line(o, set, reset, line, len);
1164                break;
1165        case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1166                fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1167                        diff_line_prefix(o), line);
1168                break;
1169        case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1170                fprintf(o->file, "%sSubmodule %s contains modified content\n",
1171                        diff_line_prefix(o), line);
1172                break;
1173        case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1174                emit_line(o, "", "", " 0 files changed\n",
1175                          strlen(" 0 files changed\n"));
1176                break;
1177        case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1178                emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1179                break;
1180        case DIFF_SYMBOL_WORD_DIFF:
1181                fprintf(o->file, "%.*s", len, line);
1182                break;
1183        case DIFF_SYMBOL_STAT_SEP:
1184                fputs(o->stat_sep, o->file);
1185                break;
1186        default:
1187                die("BUG: unknown diff symbol");
1188        }
1189        strbuf_release(&sb);
1190}
1191
1192static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1193                             const char *line, int len, unsigned flags)
1194{
1195        struct emitted_diff_symbol e = {line, len, flags, s};
1196
1197        if (o->emitted_symbols)
1198                append_emitted_diff_symbol(o, &e);
1199        else
1200                emit_diff_symbol_from_struct(o, &e);
1201}
1202
1203void diff_emit_submodule_del(struct diff_options *o, const char *line)
1204{
1205        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1206}
1207
1208void diff_emit_submodule_add(struct diff_options *o, const char *line)
1209{
1210        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1211}
1212
1213void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1214{
1215        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1216                         path, strlen(path), 0);
1217}
1218
1219void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1220{
1221        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1222                         path, strlen(path), 0);
1223}
1224
1225void diff_emit_submodule_header(struct diff_options *o, const char *header)
1226{
1227        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1228                         header, strlen(header), 0);
1229}
1230
1231void diff_emit_submodule_error(struct diff_options *o, const char *err)
1232{
1233        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1234}
1235
1236void diff_emit_submodule_pipethrough(struct diff_options *o,
1237                                     const char *line, int len)
1238{
1239        emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1240}
1241
1242static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1243{
1244        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1245              ecbdata->blank_at_eof_in_preimage &&
1246              ecbdata->blank_at_eof_in_postimage &&
1247              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1248              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1249                return 0;
1250        return ws_blank_line(line, len, ecbdata->ws_rule);
1251}
1252
1253static void emit_add_line(const char *reset,
1254                          struct emit_callback *ecbdata,
1255                          const char *line, int len)
1256{
1257        unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1258        if (new_blank_line_at_eof(ecbdata, line, len))
1259                flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1260
1261        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1262}
1263
1264static void emit_del_line(const char *reset,
1265                          struct emit_callback *ecbdata,
1266                          const char *line, int len)
1267{
1268        unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1269        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1270}
1271
1272static void emit_context_line(const char *reset,
1273                              struct emit_callback *ecbdata,
1274                              const char *line, int len)
1275{
1276        unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1277        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1278}
1279
1280static void emit_hunk_header(struct emit_callback *ecbdata,
1281                             const char *line, int len)
1282{
1283        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1284        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1285        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1286        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1287        static const char atat[2] = { '@', '@' };
1288        const char *cp, *ep;
1289        struct strbuf msgbuf = STRBUF_INIT;
1290        int org_len = len;
1291        int i = 1;
1292
1293        /*
1294         * As a hunk header must begin with "@@ -<old>, +<new> @@",
1295         * it always is at least 10 bytes long.
1296         */
1297        if (len < 10 ||
1298            memcmp(line, atat, 2) ||
1299            !(ep = memmem(line + 2, len - 2, atat, 2))) {
1300                emit_diff_symbol(ecbdata->opt,
1301                                 DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1302                return;
1303        }
1304        ep += 2; /* skip over @@ */
1305
1306        /* The hunk header in fraginfo color */
1307        strbuf_addstr(&msgbuf, frag);
1308        strbuf_add(&msgbuf, line, ep - line);
1309        strbuf_addstr(&msgbuf, reset);
1310
1311        /*
1312         * trailing "\r\n"
1313         */
1314        for ( ; i < 3; i++)
1315                if (line[len - i] == '\r' || line[len - i] == '\n')
1316                        len--;
1317
1318        /* blank before the func header */
1319        for (cp = ep; ep - line < len; ep++)
1320                if (*ep != ' ' && *ep != '\t')
1321                        break;
1322        if (ep != cp) {
1323                strbuf_addstr(&msgbuf, context);
1324                strbuf_add(&msgbuf, cp, ep - cp);
1325                strbuf_addstr(&msgbuf, reset);
1326        }
1327
1328        if (ep < line + len) {
1329                strbuf_addstr(&msgbuf, func);
1330                strbuf_add(&msgbuf, ep, line + len - ep);
1331                strbuf_addstr(&msgbuf, reset);
1332        }
1333
1334        strbuf_add(&msgbuf, line + len, org_len - len);
1335        strbuf_complete_line(&msgbuf);
1336        emit_diff_symbol(ecbdata->opt,
1337                         DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1338        strbuf_release(&msgbuf);
1339}
1340
1341static struct diff_tempfile *claim_diff_tempfile(void) {
1342        int i;
1343        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1344                if (!diff_temp[i].name)
1345                        return diff_temp + i;
1346        die("BUG: diff is failing to clean up its tempfiles");
1347}
1348
1349static void remove_tempfile(void)
1350{
1351        int i;
1352        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1353                if (is_tempfile_active(diff_temp[i].tempfile))
1354                        delete_tempfile(&diff_temp[i].tempfile);
1355                diff_temp[i].name = NULL;
1356        }
1357}
1358
1359static void add_line_count(struct strbuf *out, int count)
1360{
1361        switch (count) {
1362        case 0:
1363                strbuf_addstr(out, "0,0");
1364                break;
1365        case 1:
1366                strbuf_addstr(out, "1");
1367                break;
1368        default:
1369                strbuf_addf(out, "1,%d", count);
1370                break;
1371        }
1372}
1373
1374static void emit_rewrite_lines(struct emit_callback *ecb,
1375                               int prefix, const char *data, int size)
1376{
1377        const char *endp = NULL;
1378        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1379
1380        while (0 < size) {
1381                int len;
1382
1383                endp = memchr(data, '\n', size);
1384                len = endp ? (endp - data + 1) : size;
1385                if (prefix != '+') {
1386                        ecb->lno_in_preimage++;
1387                        emit_del_line(reset, ecb, data, len);
1388                } else {
1389                        ecb->lno_in_postimage++;
1390                        emit_add_line(reset, ecb, data, len);
1391                }
1392                size -= len;
1393                data += len;
1394        }
1395        if (!endp)
1396                emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1397}
1398
1399static void emit_rewrite_diff(const char *name_a,
1400                              const char *name_b,
1401                              struct diff_filespec *one,
1402                              struct diff_filespec *two,
1403                              struct userdiff_driver *textconv_one,
1404                              struct userdiff_driver *textconv_two,
1405                              struct diff_options *o)
1406{
1407        int lc_a, lc_b;
1408        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1409        const char *a_prefix, *b_prefix;
1410        char *data_one, *data_two;
1411        size_t size_one, size_two;
1412        struct emit_callback ecbdata;
1413        struct strbuf out = STRBUF_INIT;
1414
1415        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
1416                a_prefix = o->b_prefix;
1417                b_prefix = o->a_prefix;
1418        } else {
1419                a_prefix = o->a_prefix;
1420                b_prefix = o->b_prefix;
1421        }
1422
1423        name_a += (*name_a == '/');
1424        name_b += (*name_b == '/');
1425
1426        strbuf_reset(&a_name);
1427        strbuf_reset(&b_name);
1428        quote_two_c_style(&a_name, a_prefix, name_a, 0);
1429        quote_two_c_style(&b_name, b_prefix, name_b, 0);
1430
1431        size_one = fill_textconv(textconv_one, one, &data_one);
1432        size_two = fill_textconv(textconv_two, two, &data_two);
1433
1434        memset(&ecbdata, 0, sizeof(ecbdata));
1435        ecbdata.color_diff = want_color(o->use_color);
1436        ecbdata.ws_rule = whitespace_rule(name_b);
1437        ecbdata.opt = o;
1438        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1439                mmfile_t mf1, mf2;
1440                mf1.ptr = (char *)data_one;
1441                mf2.ptr = (char *)data_two;
1442                mf1.size = size_one;
1443                mf2.size = size_two;
1444                check_blank_at_eof(&mf1, &mf2, &ecbdata);
1445        }
1446        ecbdata.lno_in_preimage = 1;
1447        ecbdata.lno_in_postimage = 1;
1448
1449        lc_a = count_lines(data_one, size_one);
1450        lc_b = count_lines(data_two, size_two);
1451
1452        emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1453                         a_name.buf, a_name.len, 0);
1454        emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1455                         b_name.buf, b_name.len, 0);
1456
1457        strbuf_addstr(&out, "@@ -");
1458        if (!o->irreversible_delete)
1459                add_line_count(&out, lc_a);
1460        else
1461                strbuf_addstr(&out, "?,?");
1462        strbuf_addstr(&out, " +");
1463        add_line_count(&out, lc_b);
1464        strbuf_addstr(&out, " @@\n");
1465        emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1466        strbuf_release(&out);
1467
1468        if (lc_a && !o->irreversible_delete)
1469                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1470        if (lc_b)
1471                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1472        if (textconv_one)
1473                free((char *)data_one);
1474        if (textconv_two)
1475                free((char *)data_two);
1476}
1477
1478struct diff_words_buffer {
1479        mmfile_t text;
1480        unsigned long alloc;
1481        struct diff_words_orig {
1482                const char *begin, *end;
1483        } *orig;
1484        int orig_nr, orig_alloc;
1485};
1486
1487static void diff_words_append(char *line, unsigned long len,
1488                struct diff_words_buffer *buffer)
1489{
1490        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1491        line++;
1492        len--;
1493        memcpy(buffer->text.ptr + buffer->text.size, line, len);
1494        buffer->text.size += len;
1495        buffer->text.ptr[buffer->text.size] = '\0';
1496}
1497
1498struct diff_words_style_elem {
1499        const char *prefix;
1500        const char *suffix;
1501        const char *color; /* NULL; filled in by the setup code if
1502                            * color is enabled */
1503};
1504
1505struct diff_words_style {
1506        enum diff_words_type type;
1507        struct diff_words_style_elem new, old, ctx;
1508        const char *newline;
1509};
1510
1511static struct diff_words_style diff_words_styles[] = {
1512        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1513        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1514        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1515};
1516
1517struct diff_words_data {
1518        struct diff_words_buffer minus, plus;
1519        const char *current_plus;
1520        int last_minus;
1521        struct diff_options *opt;
1522        regex_t *word_regex;
1523        enum diff_words_type type;
1524        struct diff_words_style *style;
1525};
1526
1527static int fn_out_diff_words_write_helper(struct diff_options *o,
1528                                          struct diff_words_style_elem *st_el,
1529                                          const char *newline,
1530                                          size_t count, const char *buf)
1531{
1532        int print = 0;
1533        struct strbuf sb = STRBUF_INIT;
1534
1535        while (count) {
1536                char *p = memchr(buf, '\n', count);
1537                if (print)
1538                        strbuf_addstr(&sb, diff_line_prefix(o));
1539
1540                if (p != buf) {
1541                        const char *reset = st_el->color && *st_el->color ?
1542                                            GIT_COLOR_RESET : NULL;
1543                        if (st_el->color && *st_el->color)
1544                                strbuf_addstr(&sb, st_el->color);
1545                        strbuf_addstr(&sb, st_el->prefix);
1546                        strbuf_add(&sb, buf, p ? p - buf : count);
1547                        strbuf_addstr(&sb, st_el->suffix);
1548                        if (reset)
1549                                strbuf_addstr(&sb, reset);
1550                }
1551                if (!p)
1552                        goto out;
1553
1554                strbuf_addstr(&sb, newline);
1555                count -= p + 1 - buf;
1556                buf = p + 1;
1557                print = 1;
1558                if (count) {
1559                        emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1560                                         sb.buf, sb.len, 0);
1561                        strbuf_reset(&sb);
1562                }
1563        }
1564
1565out:
1566        if (sb.len)
1567                emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1568                                 sb.buf, sb.len, 0);
1569        strbuf_release(&sb);
1570        return 0;
1571}
1572
1573/*
1574 * '--color-words' algorithm can be described as:
1575 *
1576 *   1. collect the minus/plus lines of a diff hunk, divided into
1577 *      minus-lines and plus-lines;
1578 *
1579 *   2. break both minus-lines and plus-lines into words and
1580 *      place them into two mmfile_t with one word for each line;
1581 *
1582 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1583 *
1584 * And for the common parts of the both file, we output the plus side text.
1585 * diff_words->current_plus is used to trace the current position of the plus file
1586 * which printed. diff_words->last_minus is used to trace the last minus word
1587 * printed.
1588 *
1589 * For '--graph' to work with '--color-words', we need to output the graph prefix
1590 * on each line of color words output. Generally, there are two conditions on
1591 * which we should output the prefix.
1592 *
1593 *   1. diff_words->last_minus == 0 &&
1594 *      diff_words->current_plus == diff_words->plus.text.ptr
1595 *
1596 *      that is: the plus text must start as a new line, and if there is no minus
1597 *      word printed, a graph prefix must be printed.
1598 *
1599 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1600 *      *(diff_words->current_plus - 1) == '\n'
1601 *
1602 *      that is: a graph prefix must be printed following a '\n'
1603 */
1604static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1605{
1606        if ((diff_words->last_minus == 0 &&
1607                diff_words->current_plus == diff_words->plus.text.ptr) ||
1608                (diff_words->current_plus > diff_words->plus.text.ptr &&
1609                *(diff_words->current_plus - 1) == '\n')) {
1610                return 1;
1611        } else {
1612                return 0;
1613        }
1614}
1615
1616static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1617{
1618        struct diff_words_data *diff_words = priv;
1619        struct diff_words_style *style = diff_words->style;
1620        int minus_first, minus_len, plus_first, plus_len;
1621        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1622        struct diff_options *opt = diff_words->opt;
1623        const char *line_prefix;
1624
1625        if (line[0] != '@' || parse_hunk_header(line, len,
1626                        &minus_first, &minus_len, &plus_first, &plus_len))
1627                return;
1628
1629        assert(opt);
1630        line_prefix = diff_line_prefix(opt);
1631
1632        /* POSIX requires that first be decremented by one if len == 0... */
1633        if (minus_len) {
1634                minus_begin = diff_words->minus.orig[minus_first].begin;
1635                minus_end =
1636                        diff_words->minus.orig[minus_first + minus_len - 1].end;
1637        } else
1638                minus_begin = minus_end =
1639                        diff_words->minus.orig[minus_first].end;
1640
1641        if (plus_len) {
1642                plus_begin = diff_words->plus.orig[plus_first].begin;
1643                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1644        } else
1645                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1646
1647        if (color_words_output_graph_prefix(diff_words)) {
1648                fputs(line_prefix, diff_words->opt->file);
1649        }
1650        if (diff_words->current_plus != plus_begin) {
1651                fn_out_diff_words_write_helper(diff_words->opt,
1652                                &style->ctx, style->newline,
1653                                plus_begin - diff_words->current_plus,
1654                                diff_words->current_plus);
1655        }
1656        if (minus_begin != minus_end) {
1657                fn_out_diff_words_write_helper(diff_words->opt,
1658                                &style->old, style->newline,
1659                                minus_end - minus_begin, minus_begin);
1660        }
1661        if (plus_begin != plus_end) {
1662                fn_out_diff_words_write_helper(diff_words->opt,
1663                                &style->new, style->newline,
1664                                plus_end - plus_begin, plus_begin);
1665        }
1666
1667        diff_words->current_plus = plus_end;
1668        diff_words->last_minus = minus_first;
1669}
1670
1671/* This function starts looking at *begin, and returns 0 iff a word was found. */
1672static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1673                int *begin, int *end)
1674{
1675        if (word_regex && *begin < buffer->size) {
1676                regmatch_t match[1];
1677                if (!regexec_buf(word_regex, buffer->ptr + *begin,
1678                                 buffer->size - *begin, 1, match, 0)) {
1679                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1680                                        '\n', match[0].rm_eo - match[0].rm_so);
1681                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1682                        *begin += match[0].rm_so;
1683                        return *begin >= *end;
1684                }
1685                return -1;
1686        }
1687
1688        /* find the next word */
1689        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1690                (*begin)++;
1691        if (*begin >= buffer->size)
1692                return -1;
1693
1694        /* find the end of the word */
1695        *end = *begin + 1;
1696        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1697                (*end)++;
1698
1699        return 0;
1700}
1701
1702/*
1703 * This function splits the words in buffer->text, stores the list with
1704 * newline separator into out, and saves the offsets of the original words
1705 * in buffer->orig.
1706 */
1707static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1708                regex_t *word_regex)
1709{
1710        int i, j;
1711        long alloc = 0;
1712
1713        out->size = 0;
1714        out->ptr = NULL;
1715
1716        /* fake an empty "0th" word */
1717        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1718        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1719        buffer->orig_nr = 1;
1720
1721        for (i = 0; i < buffer->text.size; i++) {
1722                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1723                        return;
1724
1725                /* store original boundaries */
1726                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1727                                buffer->orig_alloc);
1728                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1729                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1730                buffer->orig_nr++;
1731
1732                /* store one word */
1733                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1734                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1735                out->ptr[out->size + j - i] = '\n';
1736                out->size += j - i + 1;
1737
1738                i = j - 1;
1739        }
1740}
1741
1742/* this executes the word diff on the accumulated buffers */
1743static void diff_words_show(struct diff_words_data *diff_words)
1744{
1745        xpparam_t xpp;
1746        xdemitconf_t xecfg;
1747        mmfile_t minus, plus;
1748        struct diff_words_style *style = diff_words->style;
1749
1750        struct diff_options *opt = diff_words->opt;
1751        const char *line_prefix;
1752
1753        assert(opt);
1754        line_prefix = diff_line_prefix(opt);
1755
1756        /* special case: only removal */
1757        if (!diff_words->plus.text.size) {
1758                emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1759                                 line_prefix, strlen(line_prefix), 0);
1760                fn_out_diff_words_write_helper(diff_words->opt,
1761                        &style->old, style->newline,
1762                        diff_words->minus.text.size,
1763                        diff_words->minus.text.ptr);
1764                diff_words->minus.text.size = 0;
1765                return;
1766        }
1767
1768        diff_words->current_plus = diff_words->plus.text.ptr;
1769        diff_words->last_minus = 0;
1770
1771        memset(&xpp, 0, sizeof(xpp));
1772        memset(&xecfg, 0, sizeof(xecfg));
1773        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1774        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1775        xpp.flags = 0;
1776        /* as only the hunk header will be parsed, we need a 0-context */
1777        xecfg.ctxlen = 0;
1778        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1779                          &xpp, &xecfg))
1780                die("unable to generate word diff");
1781        free(minus.ptr);
1782        free(plus.ptr);
1783        if (diff_words->current_plus != diff_words->plus.text.ptr +
1784                        diff_words->plus.text.size) {
1785                if (color_words_output_graph_prefix(diff_words))
1786                        emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1787                                         line_prefix, strlen(line_prefix), 0);
1788                fn_out_diff_words_write_helper(diff_words->opt,
1789                        &style->ctx, style->newline,
1790                        diff_words->plus.text.ptr + diff_words->plus.text.size
1791                        - diff_words->current_plus, diff_words->current_plus);
1792        }
1793        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1794}
1795
1796/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1797static void diff_words_flush(struct emit_callback *ecbdata)
1798{
1799        struct diff_options *wo = ecbdata->diff_words->opt;
1800
1801        if (ecbdata->diff_words->minus.text.size ||
1802            ecbdata->diff_words->plus.text.size)
1803                diff_words_show(ecbdata->diff_words);
1804
1805        if (wo->emitted_symbols) {
1806                struct diff_options *o = ecbdata->opt;
1807                struct emitted_diff_symbols *wol = wo->emitted_symbols;
1808                int i;
1809
1810                /*
1811                 * NEEDSWORK:
1812                 * Instead of appending each, concat all words to a line?
1813                 */
1814                for (i = 0; i < wol->nr; i++)
1815                        append_emitted_diff_symbol(o, &wol->buf[i]);
1816
1817                for (i = 0; i < wol->nr; i++)
1818                        free((void *)wol->buf[i].line);
1819
1820                wol->nr = 0;
1821        }
1822}
1823
1824static void diff_filespec_load_driver(struct diff_filespec *one)
1825{
1826        /* Use already-loaded driver */
1827        if (one->driver)
1828                return;
1829
1830        if (S_ISREG(one->mode))
1831                one->driver = userdiff_find_by_path(one->path);
1832
1833        /* Fallback to default settings */
1834        if (!one->driver)
1835                one->driver = userdiff_find_by_name("default");
1836}
1837
1838static const char *userdiff_word_regex(struct diff_filespec *one)
1839{
1840        diff_filespec_load_driver(one);
1841        return one->driver->word_regex;
1842}
1843
1844static void init_diff_words_data(struct emit_callback *ecbdata,
1845                                 struct diff_options *orig_opts,
1846                                 struct diff_filespec *one,
1847                                 struct diff_filespec *two)
1848{
1849        int i;
1850        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1851        memcpy(o, orig_opts, sizeof(struct diff_options));
1852
1853        ecbdata->diff_words =
1854                xcalloc(1, sizeof(struct diff_words_data));
1855        ecbdata->diff_words->type = o->word_diff;
1856        ecbdata->diff_words->opt = o;
1857
1858        if (orig_opts->emitted_symbols)
1859                o->emitted_symbols =
1860                        xcalloc(1, sizeof(struct emitted_diff_symbols));
1861
1862        if (!o->word_regex)
1863                o->word_regex = userdiff_word_regex(one);
1864        if (!o->word_regex)
1865                o->word_regex = userdiff_word_regex(two);
1866        if (!o->word_regex)
1867                o->word_regex = diff_word_regex_cfg;
1868        if (o->word_regex) {
1869                ecbdata->diff_words->word_regex = (regex_t *)
1870                        xmalloc(sizeof(regex_t));
1871                if (regcomp(ecbdata->diff_words->word_regex,
1872                            o->word_regex,
1873                            REG_EXTENDED | REG_NEWLINE))
1874                        die ("Invalid regular expression: %s",
1875                             o->word_regex);
1876        }
1877        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1878                if (o->word_diff == diff_words_styles[i].type) {
1879                        ecbdata->diff_words->style =
1880                                &diff_words_styles[i];
1881                        break;
1882                }
1883        }
1884        if (want_color(o->use_color)) {
1885                struct diff_words_style *st = ecbdata->diff_words->style;
1886                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1887                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1888                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1889        }
1890}
1891
1892static void free_diff_words_data(struct emit_callback *ecbdata)
1893{
1894        if (ecbdata->diff_words) {
1895                diff_words_flush(ecbdata);
1896                free (ecbdata->diff_words->opt->emitted_symbols);
1897                free (ecbdata->diff_words->opt);
1898                free (ecbdata->diff_words->minus.text.ptr);
1899                free (ecbdata->diff_words->minus.orig);
1900                free (ecbdata->diff_words->plus.text.ptr);
1901                free (ecbdata->diff_words->plus.orig);
1902                if (ecbdata->diff_words->word_regex) {
1903                        regfree(ecbdata->diff_words->word_regex);
1904                        free(ecbdata->diff_words->word_regex);
1905                }
1906                FREE_AND_NULL(ecbdata->diff_words);
1907        }
1908}
1909
1910const char *diff_get_color(int diff_use_color, enum color_diff ix)
1911{
1912        if (want_color(diff_use_color))
1913                return diff_colors[ix];
1914        return "";
1915}
1916
1917const char *diff_line_prefix(struct diff_options *opt)
1918{
1919        struct strbuf *msgbuf;
1920        if (!opt->output_prefix)
1921                return "";
1922
1923        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1924        return msgbuf->buf;
1925}
1926
1927static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1928{
1929        const char *cp;
1930        unsigned long allot;
1931        size_t l = len;
1932
1933        cp = line;
1934        allot = l;
1935        while (0 < l) {
1936                (void) utf8_width(&cp, &l);
1937                if (!cp)
1938                        break; /* truncated in the middle? */
1939        }
1940        return allot - l;
1941}
1942
1943static void find_lno(const char *line, struct emit_callback *ecbdata)
1944{
1945        const char *p;
1946        ecbdata->lno_in_preimage = 0;
1947        ecbdata->lno_in_postimage = 0;
1948        p = strchr(line, '-');
1949        if (!p)
1950                return; /* cannot happen */
1951        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1952        p = strchr(p, '+');
1953        if (!p)
1954                return; /* cannot happen */
1955        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1956}
1957
1958static void fn_out_consume(void *priv, char *line, unsigned long len)
1959{
1960        struct emit_callback *ecbdata = priv;
1961        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1962        struct diff_options *o = ecbdata->opt;
1963
1964        o->found_changes = 1;
1965
1966        if (ecbdata->header) {
1967                emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
1968                                 ecbdata->header->buf, ecbdata->header->len, 0);
1969                strbuf_reset(ecbdata->header);
1970                ecbdata->header = NULL;
1971        }
1972
1973        if (ecbdata->label_path[0]) {
1974                emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1975                                 ecbdata->label_path[0],
1976                                 strlen(ecbdata->label_path[0]), 0);
1977                emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1978                                 ecbdata->label_path[1],
1979                                 strlen(ecbdata->label_path[1]), 0);
1980                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1981        }
1982
1983        if (diff_suppress_blank_empty
1984            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1985                line[0] = '\n';
1986                len = 1;
1987        }
1988
1989        if (line[0] == '@') {
1990                if (ecbdata->diff_words)
1991                        diff_words_flush(ecbdata);
1992                len = sane_truncate_line(ecbdata, line, len);
1993                find_lno(line, ecbdata);
1994                emit_hunk_header(ecbdata, line, len);
1995                return;
1996        }
1997
1998        if (ecbdata->diff_words) {
1999                enum diff_symbol s =
2000                        ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2001                        DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2002                if (line[0] == '-') {
2003                        diff_words_append(line, len,
2004                                          &ecbdata->diff_words->minus);
2005                        return;
2006                } else if (line[0] == '+') {
2007                        diff_words_append(line, len,
2008                                          &ecbdata->diff_words->plus);
2009                        return;
2010                } else if (starts_with(line, "\\ ")) {
2011                        /*
2012                         * Eat the "no newline at eof" marker as if we
2013                         * saw a "+" or "-" line with nothing on it,
2014                         * and return without diff_words_flush() to
2015                         * defer processing. If this is the end of
2016                         * preimage, more "+" lines may come after it.
2017                         */
2018                        return;
2019                }
2020                diff_words_flush(ecbdata);
2021                emit_diff_symbol(o, s, line, len, 0);
2022                return;
2023        }
2024
2025        switch (line[0]) {
2026        case '+':
2027                ecbdata->lno_in_postimage++;
2028                emit_add_line(reset, ecbdata, line + 1, len - 1);
2029                break;
2030        case '-':
2031                ecbdata->lno_in_preimage++;
2032                emit_del_line(reset, ecbdata, line + 1, len - 1);
2033                break;
2034        case ' ':
2035                ecbdata->lno_in_postimage++;
2036                ecbdata->lno_in_preimage++;
2037                emit_context_line(reset, ecbdata, line + 1, len - 1);
2038                break;
2039        default:
2040                /* incomplete line at the end */
2041                ecbdata->lno_in_preimage++;
2042                emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2043                                 line, len, 0);
2044                break;
2045        }
2046}
2047
2048static char *pprint_rename(const char *a, const char *b)
2049{
2050        const char *old = a;
2051        const char *new = b;
2052        struct strbuf name = STRBUF_INIT;
2053        int pfx_length, sfx_length;
2054        int pfx_adjust_for_slash;
2055        int len_a = strlen(a);
2056        int len_b = strlen(b);
2057        int a_midlen, b_midlen;
2058        int qlen_a = quote_c_style(a, NULL, NULL, 0);
2059        int qlen_b = quote_c_style(b, NULL, NULL, 0);
2060
2061        if (qlen_a || qlen_b) {
2062                quote_c_style(a, &name, NULL, 0);
2063                strbuf_addstr(&name, " => ");
2064                quote_c_style(b, &name, NULL, 0);
2065                return strbuf_detach(&name, NULL);
2066        }
2067
2068        /* Find common prefix */
2069        pfx_length = 0;
2070        while (*old && *new && *old == *new) {
2071                if (*old == '/')
2072                        pfx_length = old - a + 1;
2073                old++;
2074                new++;
2075        }
2076
2077        /* Find common suffix */
2078        old = a + len_a;
2079        new = b + len_b;
2080        sfx_length = 0;
2081        /*
2082         * If there is a common prefix, it must end in a slash.  In
2083         * that case we let this loop run 1 into the prefix to see the
2084         * same slash.
2085         *
2086         * If there is no common prefix, we cannot do this as it would
2087         * underrun the input strings.
2088         */
2089        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2090        while (a + pfx_length - pfx_adjust_for_slash <= old &&
2091               b + pfx_length - pfx_adjust_for_slash <= new &&
2092               *old == *new) {
2093                if (*old == '/')
2094                        sfx_length = len_a - (old - a);
2095                old--;
2096                new--;
2097        }
2098
2099        /*
2100         * pfx{mid-a => mid-b}sfx
2101         * {pfx-a => pfx-b}sfx
2102         * pfx{sfx-a => sfx-b}
2103         * name-a => name-b
2104         */
2105        a_midlen = len_a - pfx_length - sfx_length;
2106        b_midlen = len_b - pfx_length - sfx_length;
2107        if (a_midlen < 0)
2108                a_midlen = 0;
2109        if (b_midlen < 0)
2110                b_midlen = 0;
2111
2112        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2113        if (pfx_length + sfx_length) {
2114                strbuf_add(&name, a, pfx_length);
2115                strbuf_addch(&name, '{');
2116        }
2117        strbuf_add(&name, a + pfx_length, a_midlen);
2118        strbuf_addstr(&name, " => ");
2119        strbuf_add(&name, b + pfx_length, b_midlen);
2120        if (pfx_length + sfx_length) {
2121                strbuf_addch(&name, '}');
2122                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
2123        }
2124        return strbuf_detach(&name, NULL);
2125}
2126
2127struct diffstat_t {
2128        int nr;
2129        int alloc;
2130        struct diffstat_file {
2131                char *from_name;
2132                char *name;
2133                char *print_name;
2134                unsigned is_unmerged:1;
2135                unsigned is_binary:1;
2136                unsigned is_renamed:1;
2137                unsigned is_interesting:1;
2138                uintmax_t added, deleted;
2139        } **files;
2140};
2141
2142static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2143                                          const char *name_a,
2144                                          const char *name_b)
2145{
2146        struct diffstat_file *x;
2147        x = xcalloc(1, sizeof(*x));
2148        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2149        diffstat->files[diffstat->nr++] = x;
2150        if (name_b) {
2151                x->from_name = xstrdup(name_a);
2152                x->name = xstrdup(name_b);
2153                x->is_renamed = 1;
2154        }
2155        else {
2156                x->from_name = NULL;
2157                x->name = xstrdup(name_a);
2158        }
2159        return x;
2160}
2161
2162static void diffstat_consume(void *priv, char *line, unsigned long len)
2163{
2164        struct diffstat_t *diffstat = priv;
2165        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2166
2167        if (line[0] == '+')
2168                x->added++;
2169        else if (line[0] == '-')
2170                x->deleted++;
2171}
2172
2173const char mime_boundary_leader[] = "------------";
2174
2175static int scale_linear(int it, int width, int max_change)
2176{
2177        if (!it)
2178                return 0;
2179        /*
2180         * make sure that at least one '-' or '+' is printed if
2181         * there is any change to this path. The easiest way is to
2182         * scale linearly as if the alloted width is one column shorter
2183         * than it is, and then add 1 to the result.
2184         */
2185        return 1 + (it * (width - 1) / max_change);
2186}
2187
2188static void show_graph(struct strbuf *out, char ch, int cnt,
2189                       const char *set, const char *reset)
2190{
2191        if (cnt <= 0)
2192                return;
2193        strbuf_addstr(out, set);
2194        strbuf_addchars(out, ch, cnt);
2195        strbuf_addstr(out, reset);
2196}
2197
2198static void fill_print_name(struct diffstat_file *file)
2199{
2200        char *pname;
2201
2202        if (file->print_name)
2203                return;
2204
2205        if (!file->is_renamed) {
2206                struct strbuf buf = STRBUF_INIT;
2207                if (quote_c_style(file->name, &buf, NULL, 0)) {
2208                        pname = strbuf_detach(&buf, NULL);
2209                } else {
2210                        pname = file->name;
2211                        strbuf_release(&buf);
2212                }
2213        } else {
2214                pname = pprint_rename(file->from_name, file->name);
2215        }
2216        file->print_name = pname;
2217}
2218
2219static void print_stat_summary_inserts_deletes(struct diff_options *options,
2220                int files, int insertions, int deletions)
2221{
2222        struct strbuf sb = STRBUF_INIT;
2223
2224        if (!files) {
2225                assert(insertions == 0 && deletions == 0);
2226                emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2227                                 NULL, 0, 0);
2228                return;
2229        }
2230
2231        strbuf_addf(&sb,
2232                    (files == 1) ? " %d file changed" : " %d files changed",
2233                    files);
2234
2235        /*
2236         * For binary diff, the caller may want to print "x files
2237         * changed" with insertions == 0 && deletions == 0.
2238         *
2239         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2240         * is probably less confusing (i.e skip over "2 files changed
2241         * but nothing about added/removed lines? Is this a bug in Git?").
2242         */
2243        if (insertions || deletions == 0) {
2244                strbuf_addf(&sb,
2245                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2246                            insertions);
2247        }
2248
2249        if (deletions || insertions == 0) {
2250                strbuf_addf(&sb,
2251                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2252                            deletions);
2253        }
2254        strbuf_addch(&sb, '\n');
2255        emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2256                         sb.buf, sb.len, 0);
2257        strbuf_release(&sb);
2258}
2259
2260void print_stat_summary(FILE *fp, int files,
2261                        int insertions, int deletions)
2262{
2263        struct diff_options o;
2264        memset(&o, 0, sizeof(o));
2265        o.file = fp;
2266
2267        print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2268}
2269
2270static void show_stats(struct diffstat_t *data, struct diff_options *options)
2271{
2272        int i, len, add, del, adds = 0, dels = 0;
2273        uintmax_t max_change = 0, max_len = 0;
2274        int total_files = data->nr, count;
2275        int width, name_width, graph_width, number_width = 0, bin_width = 0;
2276        const char *reset, *add_c, *del_c;
2277        int extra_shown = 0;
2278        const char *line_prefix = diff_line_prefix(options);
2279        struct strbuf out = STRBUF_INIT;
2280
2281        if (data->nr == 0)
2282                return;
2283
2284        count = options->stat_count ? options->stat_count : data->nr;
2285
2286        reset = diff_get_color_opt(options, DIFF_RESET);
2287        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2288        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2289
2290        /*
2291         * Find the longest filename and max number of changes
2292         */
2293        for (i = 0; (i < count) && (i < data->nr); i++) {
2294                struct diffstat_file *file = data->files[i];
2295                uintmax_t change = file->added + file->deleted;
2296
2297                if (!file->is_interesting && (change == 0)) {
2298                        count++; /* not shown == room for one more */
2299                        continue;
2300                }
2301                fill_print_name(file);
2302                len = strlen(file->print_name);
2303                if (max_len < len)
2304                        max_len = len;
2305
2306                if (file->is_unmerged) {
2307                        /* "Unmerged" is 8 characters */
2308                        bin_width = bin_width < 8 ? 8 : bin_width;
2309                        continue;
2310                }
2311                if (file->is_binary) {
2312                        /* "Bin XXX -> YYY bytes" */
2313                        int w = 14 + decimal_width(file->added)
2314                                + decimal_width(file->deleted);
2315                        bin_width = bin_width < w ? w : bin_width;
2316                        /* Display change counts aligned with "Bin" */
2317                        number_width = 3;
2318                        continue;
2319                }
2320
2321                if (max_change < change)
2322                        max_change = change;
2323        }
2324        count = i; /* where we can stop scanning in data->files[] */
2325
2326        /*
2327         * We have width = stat_width or term_columns() columns total.
2328         * We want a maximum of min(max_len, stat_name_width) for the name part.
2329         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2330         * We also need 1 for " " and 4 + decimal_width(max_change)
2331         * for " | NNNN " and one the empty column at the end, altogether
2332         * 6 + decimal_width(max_change).
2333         *
2334         * If there's not enough space, we will use the smaller of
2335         * stat_name_width (if set) and 5/8*width for the filename,
2336         * and the rest for constant elements + graph part, but no more
2337         * than stat_graph_width for the graph part.
2338         * (5/8 gives 50 for filename and 30 for the constant parts + graph
2339         * for the standard terminal size).
2340         *
2341         * In other words: stat_width limits the maximum width, and
2342         * stat_name_width fixes the maximum width of the filename,
2343         * and is also used to divide available columns if there
2344         * aren't enough.
2345         *
2346         * Binary files are displayed with "Bin XXX -> YYY bytes"
2347         * instead of the change count and graph. This part is treated
2348         * similarly to the graph part, except that it is not
2349         * "scaled". If total width is too small to accommodate the
2350         * guaranteed minimum width of the filename part and the
2351         * separators and this message, this message will "overflow"
2352         * making the line longer than the maximum width.
2353         */
2354
2355        if (options->stat_width == -1)
2356                width = term_columns() - strlen(line_prefix);
2357        else
2358                width = options->stat_width ? options->stat_width : 80;
2359        number_width = decimal_width(max_change) > number_width ?
2360                decimal_width(max_change) : number_width;
2361
2362        if (options->stat_graph_width == -1)
2363                options->stat_graph_width = diff_stat_graph_width;
2364
2365        /*
2366         * Guarantee 3/8*16==6 for the graph part
2367         * and 5/8*16==10 for the filename part
2368         */
2369        if (width < 16 + 6 + number_width)
2370                width = 16 + 6 + number_width;
2371
2372        /*
2373         * First assign sizes that are wanted, ignoring available width.
2374         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2375         * starting from "XXX" should fit in graph_width.
2376         */
2377        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2378        if (options->stat_graph_width &&
2379            options->stat_graph_width < graph_width)
2380                graph_width = options->stat_graph_width;
2381
2382        name_width = (options->stat_name_width > 0 &&
2383                      options->stat_name_width < max_len) ?
2384                options->stat_name_width : max_len;
2385
2386        /*
2387         * Adjust adjustable widths not to exceed maximum width
2388         */
2389        if (name_width + number_width + 6 + graph_width > width) {
2390                if (graph_width > width * 3/8 - number_width - 6) {
2391                        graph_width = width * 3/8 - number_width - 6;
2392                        if (graph_width < 6)
2393                                graph_width = 6;
2394                }
2395
2396                if (options->stat_graph_width &&
2397                    graph_width > options->stat_graph_width)
2398                        graph_width = options->stat_graph_width;
2399                if (name_width > width - number_width - 6 - graph_width)
2400                        name_width = width - number_width - 6 - graph_width;
2401                else
2402                        graph_width = width - number_width - 6 - name_width;
2403        }
2404
2405        /*
2406         * From here name_width is the width of the name area,
2407         * and graph_width is the width of the graph area.
2408         * max_change is used to scale graph properly.
2409         */
2410        for (i = 0; i < count; i++) {
2411                const char *prefix = "";
2412                struct diffstat_file *file = data->files[i];
2413                char *name = file->print_name;
2414                uintmax_t added = file->added;
2415                uintmax_t deleted = file->deleted;
2416                int name_len;
2417
2418                if (!file->is_interesting && (added + deleted == 0))
2419                        continue;
2420
2421                /*
2422                 * "scale" the filename
2423                 */
2424                len = name_width;
2425                name_len = strlen(name);
2426                if (name_width < name_len) {
2427                        char *slash;
2428                        prefix = "...";
2429                        len -= 3;
2430                        name += name_len - len;
2431                        slash = strchr(name, '/');
2432                        if (slash)
2433                                name = slash;
2434                }
2435
2436                if (file->is_binary) {
2437                        strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2438                        strbuf_addf(&out, " %*s", number_width, "Bin");
2439                        if (!added && !deleted) {
2440                                strbuf_addch(&out, '\n');
2441                                emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2442                                                 out.buf, out.len, 0);
2443                                strbuf_reset(&out);
2444                                continue;
2445                        }
2446                        strbuf_addf(&out, " %s%"PRIuMAX"%s",
2447                                del_c, deleted, reset);
2448                        strbuf_addstr(&out, " -> ");
2449                        strbuf_addf(&out, "%s%"PRIuMAX"%s",
2450                                add_c, added, reset);
2451                        strbuf_addstr(&out, " bytes\n");
2452                        emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2453                                         out.buf, out.len, 0);
2454                        strbuf_reset(&out);
2455                        continue;
2456                }
2457                else if (file->is_unmerged) {
2458                        strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2459                        strbuf_addstr(&out, " Unmerged\n");
2460                        emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2461                                         out.buf, out.len, 0);
2462                        strbuf_reset(&out);
2463                        continue;
2464                }
2465
2466                /*
2467                 * scale the add/delete
2468                 */
2469                add = added;
2470                del = deleted;
2471
2472                if (graph_width <= max_change) {
2473                        int total = scale_linear(add + del, graph_width, max_change);
2474                        if (total < 2 && add && del)
2475                                /* width >= 2 due to the sanity check */
2476                                total = 2;
2477                        if (add < del) {
2478                                add = scale_linear(add, graph_width, max_change);
2479                                del = total - add;
2480                        } else {
2481                                del = scale_linear(del, graph_width, max_change);
2482                                add = total - del;
2483                        }
2484                }
2485                strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2486                strbuf_addf(&out, " %*"PRIuMAX"%s",
2487                        number_width, added + deleted,
2488                        added + deleted ? " " : "");
2489                show_graph(&out, '+', add, add_c, reset);
2490                show_graph(&out, '-', del, del_c, reset);
2491                strbuf_addch(&out, '\n');
2492                emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2493                                 out.buf, out.len, 0);
2494                strbuf_reset(&out);
2495        }
2496
2497        for (i = 0; i < data->nr; i++) {
2498                struct diffstat_file *file = data->files[i];
2499                uintmax_t added = file->added;
2500                uintmax_t deleted = file->deleted;
2501
2502                if (file->is_unmerged ||
2503                    (!file->is_interesting && (added + deleted == 0))) {
2504                        total_files--;
2505                        continue;
2506                }
2507
2508                if (!file->is_binary) {
2509                        adds += added;
2510                        dels += deleted;
2511                }
2512                if (i < count)
2513                        continue;
2514                if (!extra_shown)
2515                        emit_diff_symbol(options,
2516                                         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2517                                         NULL, 0, 0);
2518                extra_shown = 1;
2519        }
2520
2521        print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2522        strbuf_release(&out);
2523}
2524
2525static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2526{
2527        int i, adds = 0, dels = 0, total_files = data->nr;
2528
2529        if (data->nr == 0)
2530                return;
2531
2532        for (i = 0; i < data->nr; i++) {
2533                int added = data->files[i]->added;
2534                int deleted = data->files[i]->deleted;
2535
2536                if (data->files[i]->is_unmerged ||
2537                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
2538                        total_files--;
2539                } else if (!data->files[i]->is_binary) { /* don't count bytes */
2540                        adds += added;
2541                        dels += deleted;
2542                }
2543        }
2544        print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2545}
2546
2547static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2548{
2549        int i;
2550
2551        if (data->nr == 0)
2552                return;
2553
2554        for (i = 0; i < data->nr; i++) {
2555                struct diffstat_file *file = data->files[i];
2556
2557                fprintf(options->file, "%s", diff_line_prefix(options));
2558
2559                if (file->is_binary)
2560                        fprintf(options->file, "-\t-\t");
2561                else
2562                        fprintf(options->file,
2563                                "%"PRIuMAX"\t%"PRIuMAX"\t",
2564                                file->added, file->deleted);
2565                if (options->line_termination) {
2566                        fill_print_name(file);
2567                        if (!file->is_renamed)
2568                                write_name_quoted(file->name, options->file,
2569                                                  options->line_termination);
2570                        else {
2571                                fputs(file->print_name, options->file);
2572                                putc(options->line_termination, options->file);
2573                        }
2574                } else {
2575                        if (file->is_renamed) {
2576                                putc('\0', options->file);
2577                                write_name_quoted(file->from_name, options->file, '\0');
2578                        }
2579                        write_name_quoted(file->name, options->file, '\0');
2580                }
2581        }
2582}
2583
2584struct dirstat_file {
2585        const char *name;
2586        unsigned long changed;
2587};
2588
2589struct dirstat_dir {
2590        struct dirstat_file *files;
2591        int alloc, nr, permille, cumulative;
2592};
2593
2594static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2595                unsigned long changed, const char *base, int baselen)
2596{
2597        unsigned long this_dir = 0;
2598        unsigned int sources = 0;
2599        const char *line_prefix = diff_line_prefix(opt);
2600
2601        while (dir->nr) {
2602                struct dirstat_file *f = dir->files;
2603                int namelen = strlen(f->name);
2604                unsigned long this;
2605                char *slash;
2606
2607                if (namelen < baselen)
2608                        break;
2609                if (memcmp(f->name, base, baselen))
2610                        break;
2611                slash = strchr(f->name + baselen, '/');
2612                if (slash) {
2613                        int newbaselen = slash + 1 - f->name;
2614                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2615                        sources++;
2616                } else {
2617                        this = f->changed;
2618                        dir->files++;
2619                        dir->nr--;
2620                        sources += 2;
2621                }
2622                this_dir += this;
2623        }
2624
2625        /*
2626         * We don't report dirstat's for
2627         *  - the top level
2628         *  - or cases where everything came from a single directory
2629         *    under this directory (sources == 1).
2630         */
2631        if (baselen && sources != 1) {
2632                if (this_dir) {
2633                        int permille = this_dir * 1000 / changed;
2634                        if (permille >= dir->permille) {
2635                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2636                                        permille / 10, permille % 10, baselen, base);
2637                                if (!dir->cumulative)
2638                                        return 0;
2639                        }
2640                }
2641        }
2642        return this_dir;
2643}
2644
2645static int dirstat_compare(const void *_a, const void *_b)
2646{
2647        const struct dirstat_file *a = _a;
2648        const struct dirstat_file *b = _b;
2649        return strcmp(a->name, b->name);
2650}
2651
2652static void show_dirstat(struct diff_options *options)
2653{
2654        int i;
2655        unsigned long changed;
2656        struct dirstat_dir dir;
2657        struct diff_queue_struct *q = &diff_queued_diff;
2658
2659        dir.files = NULL;
2660        dir.alloc = 0;
2661        dir.nr = 0;
2662        dir.permille = options->dirstat_permille;
2663        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2664
2665        changed = 0;
2666        for (i = 0; i < q->nr; i++) {
2667                struct diff_filepair *p = q->queue[i];
2668                const char *name;
2669                unsigned long copied, added, damage;
2670                int content_changed;
2671
2672                name = p->two->path ? p->two->path : p->one->path;
2673
2674                if (p->one->oid_valid && p->two->oid_valid)
2675                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
2676                else
2677                        content_changed = 1;
2678
2679                if (!content_changed) {
2680                        /*
2681                         * The SHA1 has not changed, so pre-/post-content is
2682                         * identical. We can therefore skip looking at the
2683                         * file contents altogether.
2684                         */
2685                        damage = 0;
2686                        goto found_damage;
2687                }
2688
2689                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2690                        /*
2691                         * In --dirstat-by-file mode, we don't really need to
2692                         * look at the actual file contents at all.
2693                         * The fact that the SHA1 changed is enough for us to
2694                         * add this file to the list of results
2695                         * (with each file contributing equal damage).
2696                         */
2697                        damage = 1;
2698                        goto found_damage;
2699                }
2700
2701                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2702                        diff_populate_filespec(p->one, 0);
2703                        diff_populate_filespec(p->two, 0);
2704                        diffcore_count_changes(p->one, p->two, NULL, NULL,
2705                                               &copied, &added);
2706                        diff_free_filespec_data(p->one);
2707                        diff_free_filespec_data(p->two);
2708                } else if (DIFF_FILE_VALID(p->one)) {
2709                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2710                        copied = added = 0;
2711                        diff_free_filespec_data(p->one);
2712                } else if (DIFF_FILE_VALID(p->two)) {
2713                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2714                        copied = 0;
2715                        added = p->two->size;
2716                        diff_free_filespec_data(p->two);
2717                } else
2718                        continue;
2719
2720                /*
2721                 * Original minus copied is the removed material,
2722                 * added is the new material.  They are both damages
2723                 * made to the preimage.
2724                 * If the resulting damage is zero, we know that
2725                 * diffcore_count_changes() considers the two entries to
2726                 * be identical, but since content_changed is true, we
2727                 * know that there must have been _some_ kind of change,
2728                 * so we force all entries to have damage > 0.
2729                 */
2730                damage = (p->one->size - copied) + added;
2731                if (!damage)
2732                        damage = 1;
2733
2734found_damage:
2735                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2736                dir.files[dir.nr].name = name;
2737                dir.files[dir.nr].changed = damage;
2738                changed += damage;
2739                dir.nr++;
2740        }
2741
2742        /* This can happen even with many files, if everything was renames */
2743        if (!changed)
2744                return;
2745
2746        /* Show all directories with more than x% of the changes */
2747        QSORT(dir.files, dir.nr, dirstat_compare);
2748        gather_dirstat(options, &dir, changed, "", 0);
2749}
2750
2751static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2752{
2753        int i;
2754        unsigned long changed;
2755        struct dirstat_dir dir;
2756
2757        if (data->nr == 0)
2758                return;
2759
2760        dir.files = NULL;
2761        dir.alloc = 0;
2762        dir.nr = 0;
2763        dir.permille = options->dirstat_permille;
2764        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2765
2766        changed = 0;
2767        for (i = 0; i < data->nr; i++) {
2768                struct diffstat_file *file = data->files[i];
2769                unsigned long damage = file->added + file->deleted;
2770                if (file->is_binary)
2771                        /*
2772                         * binary files counts bytes, not lines. Must find some
2773                         * way to normalize binary bytes vs. textual lines.
2774                         * The following heuristic assumes that there are 64
2775                         * bytes per "line".
2776                         * This is stupid and ugly, but very cheap...
2777                         */
2778                        damage = DIV_ROUND_UP(damage, 64);
2779                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2780                dir.files[dir.nr].name = file->name;
2781                dir.files[dir.nr].changed = damage;
2782                changed += damage;
2783                dir.nr++;
2784        }
2785
2786        /* This can happen even with many files, if everything was renames */
2787        if (!changed)
2788                return;
2789
2790        /* Show all directories with more than x% of the changes */
2791        QSORT(dir.files, dir.nr, dirstat_compare);
2792        gather_dirstat(options, &dir, changed, "", 0);
2793}
2794
2795static void free_diffstat_info(struct diffstat_t *diffstat)
2796{
2797        int i;
2798        for (i = 0; i < diffstat->nr; i++) {
2799                struct diffstat_file *f = diffstat->files[i];
2800                if (f->name != f->print_name)
2801                        free(f->print_name);
2802                free(f->name);
2803                free(f->from_name);
2804                free(f);
2805        }
2806        free(diffstat->files);
2807}
2808
2809struct checkdiff_t {
2810        const char *filename;
2811        int lineno;
2812        int conflict_marker_size;
2813        struct diff_options *o;
2814        unsigned ws_rule;
2815        unsigned status;
2816};
2817
2818static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2819{
2820        char firstchar;
2821        int cnt;
2822
2823        if (len < marker_size + 1)
2824                return 0;
2825        firstchar = line[0];
2826        switch (firstchar) {
2827        case '=': case '>': case '<': case '|':
2828                break;
2829        default:
2830                return 0;
2831        }
2832        for (cnt = 1; cnt < marker_size; cnt++)
2833                if (line[cnt] != firstchar)
2834                        return 0;
2835        /* line[1] thru line[marker_size-1] are same as firstchar */
2836        if (len < marker_size + 1 || !isspace(line[marker_size]))
2837                return 0;
2838        return 1;
2839}
2840
2841static void checkdiff_consume(void *priv, char *line, unsigned long len)
2842{
2843        struct checkdiff_t *data = priv;
2844        int marker_size = data->conflict_marker_size;
2845        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2846        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2847        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2848        char *err;
2849        const char *line_prefix;
2850
2851        assert(data->o);
2852        line_prefix = diff_line_prefix(data->o);
2853
2854        if (line[0] == '+') {
2855                unsigned bad;
2856                data->lineno++;
2857                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2858                        data->status |= 1;
2859                        fprintf(data->o->file,
2860                                "%s%s:%d: leftover conflict marker\n",
2861                                line_prefix, data->filename, data->lineno);
2862                }
2863                bad = ws_check(line + 1, len - 1, data->ws_rule);
2864                if (!bad)
2865                        return;
2866                data->status |= bad;
2867                err = whitespace_error_string(bad);
2868                fprintf(data->o->file, "%s%s:%d: %s.\n",
2869                        line_prefix, data->filename, data->lineno, err);
2870                free(err);
2871                emit_line(data->o, set, reset, line, 1);
2872                ws_check_emit(line + 1, len - 1, data->ws_rule,
2873                              data->o->file, set, reset, ws);
2874        } else if (line[0] == ' ') {
2875                data->lineno++;
2876        } else if (line[0] == '@') {
2877                char *plus = strchr(line, '+');
2878                if (plus)
2879                        data->lineno = strtol(plus, NULL, 10) - 1;
2880                else
2881                        die("invalid diff");
2882        }
2883}
2884
2885static unsigned char *deflate_it(char *data,
2886                                 unsigned long size,
2887                                 unsigned long *result_size)
2888{
2889        int bound;
2890        unsigned char *deflated;
2891        git_zstream stream;
2892
2893        git_deflate_init(&stream, zlib_compression_level);
2894        bound = git_deflate_bound(&stream, size);
2895        deflated = xmalloc(bound);
2896        stream.next_out = deflated;
2897        stream.avail_out = bound;
2898
2899        stream.next_in = (unsigned char *)data;
2900        stream.avail_in = size;
2901        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2902                ; /* nothing */
2903        git_deflate_end(&stream);
2904        *result_size = stream.total_out;
2905        return deflated;
2906}
2907
2908static void emit_binary_diff_body(struct diff_options *o,
2909                                  mmfile_t *one, mmfile_t *two)
2910{
2911        void *cp;
2912        void *delta;
2913        void *deflated;
2914        void *data;
2915        unsigned long orig_size;
2916        unsigned long delta_size;
2917        unsigned long deflate_size;
2918        unsigned long data_size;
2919
2920        /* We could do deflated delta, or we could do just deflated two,
2921         * whichever is smaller.
2922         */
2923        delta = NULL;
2924        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2925        if (one->size && two->size) {
2926                delta = diff_delta(one->ptr, one->size,
2927                                   two->ptr, two->size,
2928                                   &delta_size, deflate_size);
2929                if (delta) {
2930                        void *to_free = delta;
2931                        orig_size = delta_size;
2932                        delta = deflate_it(delta, delta_size, &delta_size);
2933                        free(to_free);
2934                }
2935        }
2936
2937        if (delta && delta_size < deflate_size) {
2938                char *s = xstrfmt("%lu", orig_size);
2939                emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
2940                                 s, strlen(s), 0);
2941                free(s);
2942                free(deflated);
2943                data = delta;
2944                data_size = delta_size;
2945        } else {
2946                char *s = xstrfmt("%lu", two->size);
2947                emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
2948                                 s, strlen(s), 0);
2949                free(s);
2950                free(delta);
2951                data = deflated;
2952                data_size = deflate_size;
2953        }
2954
2955        /* emit data encoded in base85 */
2956        cp = data;
2957        while (data_size) {
2958                int len;
2959                int bytes = (52 < data_size) ? 52 : data_size;
2960                char line[71];
2961                data_size -= bytes;
2962                if (bytes <= 26)
2963                        line[0] = bytes + 'A' - 1;
2964                else
2965                        line[0] = bytes - 26 + 'a' - 1;
2966                encode_85(line + 1, cp, bytes);
2967                cp = (char *) cp + bytes;
2968
2969                len = strlen(line);
2970                line[len++] = '\n';
2971                line[len] = '\0';
2972
2973                emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
2974                                 line, len, 0);
2975        }
2976        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
2977        free(data);
2978}
2979
2980static void emit_binary_diff(struct diff_options *o,
2981                             mmfile_t *one, mmfile_t *two)
2982{
2983        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
2984        emit_binary_diff_body(o, one, two);
2985        emit_binary_diff_body(o, two, one);
2986}
2987
2988int diff_filespec_is_binary(struct diff_filespec *one)
2989{
2990        if (one->is_binary == -1) {
2991                diff_filespec_load_driver(one);
2992                if (one->driver->binary != -1)
2993                        one->is_binary = one->driver->binary;
2994                else {
2995                        if (!one->data && DIFF_FILE_VALID(one))
2996                                diff_populate_filespec(one, CHECK_BINARY);
2997                        if (one->is_binary == -1 && one->data)
2998                                one->is_binary = buffer_is_binary(one->data,
2999                                                one->size);
3000                        if (one->is_binary == -1)
3001                                one->is_binary = 0;
3002                }
3003        }
3004        return one->is_binary;
3005}
3006
3007static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
3008{
3009        diff_filespec_load_driver(one);
3010        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3011}
3012
3013void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3014{
3015        if (!options->a_prefix)
3016                options->a_prefix = a;
3017        if (!options->b_prefix)
3018                options->b_prefix = b;
3019}
3020
3021struct userdiff_driver *get_textconv(struct diff_filespec *one)
3022{
3023        if (!DIFF_FILE_VALID(one))
3024                return NULL;
3025
3026        diff_filespec_load_driver(one);
3027        return userdiff_get_textconv(one->driver);
3028}
3029
3030static void builtin_diff(const char *name_a,
3031                         const char *name_b,
3032                         struct diff_filespec *one,
3033                         struct diff_filespec *two,
3034                         const char *xfrm_msg,
3035                         int must_show_header,
3036                         struct diff_options *o,
3037                         int complete_rewrite)
3038{
3039        mmfile_t mf1, mf2;
3040        const char *lbl[2];
3041        char *a_one, *b_two;
3042        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3043        const char *reset = diff_get_color_opt(o, DIFF_RESET);
3044        const char *a_prefix, *b_prefix;
3045        struct userdiff_driver *textconv_one = NULL;
3046        struct userdiff_driver *textconv_two = NULL;
3047        struct strbuf header = STRBUF_INIT;
3048        const char *line_prefix = diff_line_prefix(o);
3049
3050        diff_set_mnemonic_prefix(o, "a/", "b/");
3051        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
3052                a_prefix = o->b_prefix;
3053                b_prefix = o->a_prefix;
3054        } else {
3055                a_prefix = o->a_prefix;
3056                b_prefix = o->b_prefix;
3057        }
3058
3059        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3060            (!one->mode || S_ISGITLINK(one->mode)) &&
3061            (!two->mode || S_ISGITLINK(two->mode))) {
3062                show_submodule_summary(o, one->path ? one->path : two->path,
3063                                &one->oid, &two->oid,
3064                                two->dirty_submodule);
3065                return;
3066        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3067                   (!one->mode || S_ISGITLINK(one->mode)) &&
3068                   (!two->mode || S_ISGITLINK(two->mode))) {
3069                show_submodule_inline_diff(o, one->path ? one->path : two->path,
3070                                &one->oid, &two->oid,
3071                                two->dirty_submodule);
3072                return;
3073        }
3074
3075        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
3076                textconv_one = get_textconv(one);
3077                textconv_two = get_textconv(two);
3078        }
3079
3080        /* Never use a non-valid filename anywhere if at all possible */
3081        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3082        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3083
3084        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3085        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3086        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3087        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3088        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3089        if (lbl[0][0] == '/') {
3090                /* /dev/null */
3091                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3092                if (xfrm_msg)
3093                        strbuf_addstr(&header, xfrm_msg);
3094                must_show_header = 1;
3095        }
3096        else if (lbl[1][0] == '/') {
3097                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3098                if (xfrm_msg)
3099                        strbuf_addstr(&header, xfrm_msg);
3100                must_show_header = 1;
3101        }
3102        else {
3103                if (one->mode != two->mode) {
3104                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3105                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3106                        must_show_header = 1;
3107                }
3108                if (xfrm_msg)
3109                        strbuf_addstr(&header, xfrm_msg);
3110
3111                /*
3112                 * we do not run diff between different kind
3113                 * of objects.
3114                 */
3115                if ((one->mode ^ two->mode) & S_IFMT)
3116                        goto free_ab_and_return;
3117                if (complete_rewrite &&
3118                    (textconv_one || !diff_filespec_is_binary(one)) &&
3119                    (textconv_two || !diff_filespec_is_binary(two))) {
3120                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3121                                         header.buf, header.len, 0);
3122                        strbuf_reset(&header);
3123                        emit_rewrite_diff(name_a, name_b, one, two,
3124                                                textconv_one, textconv_two, o);
3125                        o->found_changes = 1;
3126                        goto free_ab_and_return;
3127                }
3128        }
3129
3130        if (o->irreversible_delete && lbl[1][0] == '/') {
3131                emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3132                                 header.len, 0);
3133                strbuf_reset(&header);
3134                goto free_ab_and_return;
3135        } else if (!DIFF_OPT_TST(o, TEXT) &&
3136            ( (!textconv_one && diff_filespec_is_binary(one)) ||
3137              (!textconv_two && diff_filespec_is_binary(two)) )) {
3138                struct strbuf sb = STRBUF_INIT;
3139                if (!one->data && !two->data &&
3140                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
3141                    !DIFF_OPT_TST(o, BINARY)) {
3142                        if (!oidcmp(&one->oid, &two->oid)) {
3143                                if (must_show_header)
3144                                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3145                                                         header.buf, header.len,
3146                                                         0);
3147                                goto free_ab_and_return;
3148                        }
3149                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3150                                         header.buf, header.len, 0);
3151                        strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3152                                    diff_line_prefix(o), lbl[0], lbl[1]);
3153                        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3154                                         sb.buf, sb.len, 0);
3155                        strbuf_release(&sb);
3156                        goto free_ab_and_return;
3157                }
3158                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3159                        die("unable to read files to diff");
3160                /* Quite common confusing case */
3161                if (mf1.size == mf2.size &&
3162                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3163                        if (must_show_header)
3164                                emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3165                                                 header.buf, header.len, 0);
3166                        goto free_ab_and_return;
3167                }
3168                emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3169                strbuf_reset(&header);
3170                if (DIFF_OPT_TST(o, BINARY))
3171                        emit_binary_diff(o, &mf1, &mf2);
3172                else {
3173                        strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3174                                    diff_line_prefix(o), lbl[0], lbl[1]);
3175                        emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3176                                         sb.buf, sb.len, 0);
3177                        strbuf_release(&sb);
3178                }
3179                o->found_changes = 1;
3180        } else {
3181                /* Crazy xdl interfaces.. */
3182                const char *diffopts = getenv("GIT_DIFF_OPTS");
3183                const char *v;
3184                xpparam_t xpp;
3185                xdemitconf_t xecfg;
3186                struct emit_callback ecbdata;
3187                const struct userdiff_funcname *pe;
3188
3189                if (must_show_header) {
3190                        emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3191                                         header.buf, header.len, 0);
3192                        strbuf_reset(&header);
3193                }
3194
3195                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3196                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3197
3198                pe = diff_funcname_pattern(one);
3199                if (!pe)
3200                        pe = diff_funcname_pattern(two);
3201
3202                memset(&xpp, 0, sizeof(xpp));
3203                memset(&xecfg, 0, sizeof(xecfg));
3204                memset(&ecbdata, 0, sizeof(ecbdata));
3205                ecbdata.label_path = lbl;
3206                ecbdata.color_diff = want_color(o->use_color);
3207                ecbdata.ws_rule = whitespace_rule(name_b);
3208                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3209                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
3210                ecbdata.opt = o;
3211                ecbdata.header = header.len ? &header : NULL;
3212                xpp.flags = o->xdl_opts;
3213                xecfg.ctxlen = o->context;
3214                xecfg.interhunkctxlen = o->interhunkcontext;
3215                xecfg.flags = XDL_EMIT_FUNCNAMES;
3216                if (DIFF_OPT_TST(o, FUNCCONTEXT))
3217                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3218                if (pe)
3219                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3220                if (!diffopts)
3221                        ;
3222                else if (skip_prefix(diffopts, "--unified=", &v))
3223                        xecfg.ctxlen = strtoul(v, NULL, 10);
3224                else if (skip_prefix(diffopts, "-u", &v))
3225                        xecfg.ctxlen = strtoul(v, NULL, 10);
3226                if (o->word_diff)
3227                        init_diff_words_data(&ecbdata, o, one, two);
3228                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3229                                  &xpp, &xecfg))
3230                        die("unable to generate diff for %s", one->path);
3231                if (o->word_diff)
3232                        free_diff_words_data(&ecbdata);
3233                if (textconv_one)
3234                        free(mf1.ptr);
3235                if (textconv_two)
3236                        free(mf2.ptr);
3237                xdiff_clear_find_func(&xecfg);
3238        }
3239
3240 free_ab_and_return:
3241        strbuf_release(&header);
3242        diff_free_filespec_data(one);
3243        diff_free_filespec_data(two);
3244        free(a_one);
3245        free(b_two);
3246        return;
3247}
3248
3249static void builtin_diffstat(const char *name_a, const char *name_b,
3250                             struct diff_filespec *one,
3251                             struct diff_filespec *two,
3252                             struct diffstat_t *diffstat,
3253                             struct diff_options *o,
3254                             struct diff_filepair *p)
3255{
3256        mmfile_t mf1, mf2;
3257        struct diffstat_file *data;
3258        int same_contents;
3259        int complete_rewrite = 0;
3260
3261        if (!DIFF_PAIR_UNMERGED(p)) {
3262                if (p->status == DIFF_STATUS_MODIFIED && p->score)
3263                        complete_rewrite = 1;
3264        }
3265
3266        data = diffstat_add(diffstat, name_a, name_b);
3267        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3268
3269        if (!one || !two) {
3270                data->is_unmerged = 1;
3271                return;
3272        }
3273
3274        same_contents = !oidcmp(&one->oid, &two->oid);
3275
3276        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3277                data->is_binary = 1;
3278                if (same_contents) {
3279                        data->added = 0;
3280                        data->deleted = 0;
3281                } else {
3282                        data->added = diff_filespec_size(two);
3283                        data->deleted = diff_filespec_size(one);
3284                }
3285        }
3286
3287        else if (complete_rewrite) {
3288                diff_populate_filespec(one, 0);
3289                diff_populate_filespec(two, 0);
3290                data->deleted = count_lines(one->data, one->size);
3291                data->added = count_lines(two->data, two->size);
3292        }
3293
3294        else if (!same_contents) {
3295                /* Crazy xdl interfaces.. */
3296                xpparam_t xpp;
3297                xdemitconf_t xecfg;
3298
3299                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3300                        die("unable to read files to diff");
3301
3302                memset(&xpp, 0, sizeof(xpp));
3303                memset(&xecfg, 0, sizeof(xecfg));
3304                xpp.flags = o->xdl_opts;
3305                xecfg.ctxlen = o->context;
3306                xecfg.interhunkctxlen = o->interhunkcontext;
3307                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3308                                  &xpp, &xecfg))
3309                        die("unable to generate diffstat for %s", one->path);
3310        }
3311
3312        diff_free_filespec_data(one);
3313        diff_free_filespec_data(two);
3314}
3315
3316static void builtin_checkdiff(const char *name_a, const char *name_b,
3317                              const char *attr_path,
3318                              struct diff_filespec *one,
3319                              struct diff_filespec *two,
3320                              struct diff_options *o)
3321{
3322        mmfile_t mf1, mf2;
3323        struct checkdiff_t data;
3324
3325        if (!two)
3326                return;
3327
3328        memset(&data, 0, sizeof(data));
3329        data.filename = name_b ? name_b : name_a;
3330        data.lineno = 0;
3331        data.o = o;
3332        data.ws_rule = whitespace_rule(attr_path);
3333        data.conflict_marker_size = ll_merge_marker_size(attr_path);
3334
3335        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3336                die("unable to read files to diff");
3337
3338        /*
3339         * All the other codepaths check both sides, but not checking
3340         * the "old" side here is deliberate.  We are checking the newly
3341         * introduced changes, and as long as the "new" side is text, we
3342         * can and should check what it introduces.
3343         */
3344        if (diff_filespec_is_binary(two))
3345                goto free_and_return;
3346        else {
3347                /* Crazy xdl interfaces.. */
3348                xpparam_t xpp;
3349                xdemitconf_t xecfg;
3350
3351                memset(&xpp, 0, sizeof(xpp));
3352                memset(&xecfg, 0, sizeof(xecfg));
3353                xecfg.ctxlen = 1; /* at least one context line */
3354                xpp.flags = 0;
3355                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3356                                  &xpp, &xecfg))
3357                        die("unable to generate checkdiff for %s", one->path);
3358
3359                if (data.ws_rule & WS_BLANK_AT_EOF) {
3360                        struct emit_callback ecbdata;
3361                        int blank_at_eof;
3362
3363                        ecbdata.ws_rule = data.ws_rule;
3364                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
3365                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3366
3367                        if (blank_at_eof) {
3368                                static char *err;
3369                                if (!err)
3370                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
3371                                fprintf(o->file, "%s:%d: %s.\n",
3372                                        data.filename, blank_at_eof, err);
3373                                data.status = 1; /* report errors */
3374                        }
3375                }
3376        }
3377 free_and_return:
3378        diff_free_filespec_data(one);
3379        diff_free_filespec_data(two);
3380        if (data.status)
3381                DIFF_OPT_SET(o, CHECK_FAILED);
3382}
3383
3384struct diff_filespec *alloc_filespec(const char *path)
3385{
3386        struct diff_filespec *spec;
3387
3388        FLEXPTR_ALLOC_STR(spec, path, path);
3389        spec->count = 1;
3390        spec->is_binary = -1;
3391        return spec;
3392}
3393
3394void free_filespec(struct diff_filespec *spec)
3395{
3396        if (!--spec->count) {
3397                diff_free_filespec_data(spec);
3398                free(spec);
3399        }
3400}
3401
3402void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3403                   int oid_valid, unsigned short mode)
3404{
3405        if (mode) {
3406                spec->mode = canon_mode(mode);
3407                oidcpy(&spec->oid, oid);
3408                spec->oid_valid = oid_valid;
3409        }
3410}
3411
3412/*
3413 * Given a name and sha1 pair, if the index tells us the file in
3414 * the work tree has that object contents, return true, so that
3415 * prepare_temp_file() does not have to inflate and extract.
3416 */
3417static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3418{
3419        const struct cache_entry *ce;
3420        struct stat st;
3421        int pos, len;
3422
3423        /*
3424         * We do not read the cache ourselves here, because the
3425         * benchmark with my previous version that always reads cache
3426         * shows that it makes things worse for diff-tree comparing
3427         * two linux-2.6 kernel trees in an already checked out work
3428         * tree.  This is because most diff-tree comparisons deal with
3429         * only a small number of files, while reading the cache is
3430         * expensive for a large project, and its cost outweighs the
3431         * savings we get by not inflating the object to a temporary
3432         * file.  Practically, this code only helps when we are used
3433         * by diff-cache --cached, which does read the cache before
3434         * calling us.
3435         */
3436        if (!active_cache)
3437                return 0;
3438
3439        /* We want to avoid the working directory if our caller
3440         * doesn't need the data in a normal file, this system
3441         * is rather slow with its stat/open/mmap/close syscalls,
3442         * and the object is contained in a pack file.  The pack
3443         * is probably already open and will be faster to obtain
3444         * the data through than the working directory.  Loose
3445         * objects however would tend to be slower as they need
3446         * to be individually opened and inflated.
3447         */
3448        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
3449                return 0;
3450
3451        /*
3452         * Similarly, if we'd have to convert the file contents anyway, that
3453         * makes the optimization not worthwhile.
3454         */
3455        if (!want_file && would_convert_to_git(&the_index, name))
3456                return 0;
3457
3458        len = strlen(name);
3459        pos = cache_name_pos(name, len);
3460        if (pos < 0)
3461                return 0;
3462        ce = active_cache[pos];
3463
3464        /*
3465         * This is not the sha1 we are looking for, or
3466         * unreusable because it is not a regular file.
3467         */
3468        if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3469                return 0;
3470
3471        /*
3472         * If ce is marked as "assume unchanged", there is no
3473         * guarantee that work tree matches what we are looking for.
3474         */
3475        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3476                return 0;
3477
3478        /*
3479         * If ce matches the file in the work tree, we can reuse it.
3480         */
3481        if (ce_uptodate(ce) ||
3482            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3483                return 1;
3484
3485        return 0;
3486}
3487
3488static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3489{
3490        struct strbuf buf = STRBUF_INIT;
3491        char *dirty = "";
3492
3493        /* Are we looking at the work tree? */
3494        if (s->dirty_submodule)
3495                dirty = "-dirty";
3496
3497        strbuf_addf(&buf, "Subproject commit %s%s\n",
3498                    oid_to_hex(&s->oid), dirty);
3499        s->size = buf.len;
3500        if (size_only) {
3501                s->data = NULL;
3502                strbuf_release(&buf);
3503        } else {
3504                s->data = strbuf_detach(&buf, NULL);
3505                s->should_free = 1;
3506        }
3507        return 0;
3508}
3509
3510/*
3511 * While doing rename detection and pickaxe operation, we may need to
3512 * grab the data for the blob (or file) for our own in-core comparison.
3513 * diff_filespec has data and size fields for this purpose.
3514 */
3515int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3516{
3517        int size_only = flags & CHECK_SIZE_ONLY;
3518        int err = 0;
3519        /*
3520         * demote FAIL to WARN to allow inspecting the situation
3521         * instead of refusing.
3522         */
3523        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
3524                                    ? SAFE_CRLF_WARN
3525                                    : safe_crlf);
3526
3527        if (!DIFF_FILE_VALID(s))
3528                die("internal error: asking to populate invalid file.");
3529        if (S_ISDIR(s->mode))
3530                return -1;
3531
3532        if (s->data)
3533                return 0;
3534
3535        if (size_only && 0 < s->size)
3536                return 0;
3537
3538        if (S_ISGITLINK(s->mode))
3539                return diff_populate_gitlink(s, size_only);
3540
3541        if (!s->oid_valid ||
3542            reuse_worktree_file(s->path, &s->oid, 0)) {
3543                struct strbuf buf = STRBUF_INIT;
3544                struct stat st;
3545                int fd;
3546
3547                if (lstat(s->path, &st) < 0) {
3548                        if (errno == ENOENT) {
3549                        err_empty:
3550                                err = -1;
3551                        empty:
3552                                s->data = (char *)"";
3553                                s->size = 0;
3554                                return err;
3555                        }
3556                }
3557                s->size = xsize_t(st.st_size);
3558                if (!s->size)
3559                        goto empty;
3560                if (S_ISLNK(st.st_mode)) {
3561                        struct strbuf sb = STRBUF_INIT;
3562
3563                        if (strbuf_readlink(&sb, s->path, s->size))
3564                                goto err_empty;
3565                        s->size = sb.len;
3566                        s->data = strbuf_detach(&sb, NULL);
3567                        s->should_free = 1;
3568                        return 0;
3569                }
3570
3571                /*
3572                 * Even if the caller would be happy with getting
3573                 * only the size, we cannot return early at this
3574                 * point if the path requires us to run the content
3575                 * conversion.
3576                 */
3577                if (size_only && !would_convert_to_git(&the_index, s->path))
3578                        return 0;
3579
3580                /*
3581                 * Note: this check uses xsize_t(st.st_size) that may
3582                 * not be the true size of the blob after it goes
3583                 * through convert_to_git().  This may not strictly be
3584                 * correct, but the whole point of big_file_threshold
3585                 * and is_binary check being that we want to avoid
3586                 * opening the file and inspecting the contents, this
3587                 * is probably fine.
3588                 */
3589                if ((flags & CHECK_BINARY) &&
3590                    s->size > big_file_threshold && s->is_binary == -1) {
3591                        s->is_binary = 1;
3592                        return 0;
3593                }
3594                fd = open(s->path, O_RDONLY);
3595                if (fd < 0)
3596                        goto err_empty;
3597                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3598                close(fd);
3599                s->should_munmap = 1;
3600
3601                /*
3602                 * Convert from working tree format to canonical git format
3603                 */
3604                if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
3605                        size_t size = 0;
3606                        munmap(s->data, s->size);
3607                        s->should_munmap = 0;
3608                        s->data = strbuf_detach(&buf, &size);
3609                        s->size = size;
3610                        s->should_free = 1;
3611                }
3612        }
3613        else {
3614                enum object_type type;
3615                if (size_only || (flags & CHECK_BINARY)) {
3616                        type = sha1_object_info(s->oid.hash, &s->size);
3617                        if (type < 0)
3618                                die("unable to read %s",
3619                                    oid_to_hex(&s->oid));
3620                        if (size_only)
3621                                return 0;
3622                        if (s->size > big_file_threshold && s->is_binary == -1) {
3623                                s->is_binary = 1;
3624                                return 0;
3625                        }
3626                }
3627                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3628                if (!s->data)
3629                        die("unable to read %s", oid_to_hex(&s->oid));
3630                s->should_free = 1;
3631        }
3632        return 0;
3633}
3634
3635void diff_free_filespec_blob(struct diff_filespec *s)
3636{
3637        if (s->should_free)
3638                free(s->data);
3639        else if (s->should_munmap)
3640                munmap(s->data, s->size);
3641
3642        if (s->should_free || s->should_munmap) {
3643                s->should_free = s->should_munmap = 0;
3644                s->data = NULL;
3645        }
3646}
3647
3648void diff_free_filespec_data(struct diff_filespec *s)
3649{
3650        diff_free_filespec_blob(s);
3651        FREE_AND_NULL(s->cnt_data);
3652}
3653
3654static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3655                           void *blob,
3656                           unsigned long size,
3657                           const struct object_id *oid,
3658                           int mode)
3659{
3660        struct strbuf buf = STRBUF_INIT;
3661        struct strbuf template = STRBUF_INIT;
3662        char *path_dup = xstrdup(path);
3663        const char *base = basename(path_dup);
3664
3665        /* Generate "XXXXXX_basename.ext" */
3666        strbuf_addstr(&template, "XXXXXX_");
3667        strbuf_addstr(&template, base);
3668
3669        temp->tempfile = mks_tempfile_ts(template.buf, strlen(base) + 1);
3670        if (!temp->tempfile)
3671                die_errno("unable to create temp-file");
3672        if (convert_to_working_tree(path,
3673                        (const char *)blob, (size_t)size, &buf)) {
3674                blob = buf.buf;
3675                size = buf.len;
3676        }
3677        if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
3678            close_tempfile_gently(temp->tempfile))
3679                die_errno("unable to write temp-file");
3680        temp->name = get_tempfile_path(temp->tempfile);
3681        oid_to_hex_r(temp->hex, oid);
3682        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3683        strbuf_release(&buf);
3684        strbuf_release(&template);
3685        free(path_dup);
3686}
3687
3688static struct diff_tempfile *prepare_temp_file(const char *name,
3689                struct diff_filespec *one)
3690{
3691        struct diff_tempfile *temp = claim_diff_tempfile();
3692
3693        if (!DIFF_FILE_VALID(one)) {
3694        not_a_valid_file:
3695                /* A '-' entry produces this for file-2, and
3696                 * a '+' entry produces this for file-1.
3697                 */
3698                temp->name = "/dev/null";
3699                xsnprintf(temp->hex, sizeof(temp->hex), ".");
3700                xsnprintf(temp->mode, sizeof(temp->mode), ".");
3701                return temp;
3702        }
3703
3704        if (!S_ISGITLINK(one->mode) &&
3705            (!one->oid_valid ||
3706             reuse_worktree_file(name, &one->oid, 1))) {
3707                struct stat st;
3708                if (lstat(name, &st) < 0) {
3709                        if (errno == ENOENT)
3710                                goto not_a_valid_file;
3711                        die_errno("stat(%s)", name);
3712                }
3713                if (S_ISLNK(st.st_mode)) {
3714                        struct strbuf sb = STRBUF_INIT;
3715                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
3716                                die_errno("readlink(%s)", name);
3717                        prep_temp_blob(name, temp, sb.buf, sb.len,
3718                                       (one->oid_valid ?
3719                                        &one->oid : &null_oid),
3720                                       (one->oid_valid ?
3721                                        one->mode : S_IFLNK));
3722                        strbuf_release(&sb);
3723                }
3724                else {
3725                        /* we can borrow from the file in the work tree */
3726                        temp->name = name;
3727                        if (!one->oid_valid)
3728                                oid_to_hex_r(temp->hex, &null_oid);
3729                        else
3730                                oid_to_hex_r(temp->hex, &one->oid);
3731                        /* Even though we may sometimes borrow the
3732                         * contents from the work tree, we always want
3733                         * one->mode.  mode is trustworthy even when
3734                         * !(one->oid_valid), as long as
3735                         * DIFF_FILE_VALID(one).
3736                         */
3737                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3738                }
3739                return temp;
3740        }
3741        else {
3742                if (diff_populate_filespec(one, 0))
3743                        die("cannot read data blob for %s", one->path);
3744                prep_temp_blob(name, temp, one->data, one->size,
3745                               &one->oid, one->mode);
3746        }
3747        return temp;
3748}
3749
3750static void add_external_diff_name(struct argv_array *argv,
3751                                   const char *name,
3752                                   struct diff_filespec *df)
3753{
3754        struct diff_tempfile *temp = prepare_temp_file(name, df);
3755        argv_array_push(argv, temp->name);
3756        argv_array_push(argv, temp->hex);
3757        argv_array_push(argv, temp->mode);
3758}
3759
3760/* An external diff command takes:
3761 *
3762 * diff-cmd name infile1 infile1-sha1 infile1-mode \
3763 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3764 *
3765 */
3766static void run_external_diff(const char *pgm,
3767                              const char *name,
3768                              const char *other,
3769                              struct diff_filespec *one,
3770                              struct diff_filespec *two,
3771                              const char *xfrm_msg,
3772                              int complete_rewrite,
3773                              struct diff_options *o)
3774{
3775        struct argv_array argv = ARGV_ARRAY_INIT;
3776        struct argv_array env = ARGV_ARRAY_INIT;
3777        struct diff_queue_struct *q = &diff_queued_diff;
3778
3779        argv_array_push(&argv, pgm);
3780        argv_array_push(&argv, name);
3781
3782        if (one && two) {
3783                add_external_diff_name(&argv, name, one);
3784                if (!other)
3785                        add_external_diff_name(&argv, name, two);
3786                else {
3787                        add_external_diff_name(&argv, other, two);
3788                        argv_array_push(&argv, other);
3789                        argv_array_push(&argv, xfrm_msg);
3790                }
3791        }
3792
3793        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3794        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3795
3796        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3797                die(_("external diff died, stopping at %s"), name);
3798
3799        remove_tempfile();
3800        argv_array_clear(&argv);
3801        argv_array_clear(&env);
3802}
3803
3804static int similarity_index(struct diff_filepair *p)
3805{
3806        return p->score * 100 / MAX_SCORE;
3807}
3808
3809static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3810{
3811        if (startup_info->have_repository)
3812                return find_unique_abbrev(oid->hash, abbrev);
3813        else {
3814                char *hex = oid_to_hex(oid);
3815                if (abbrev < 0)
3816                        abbrev = FALLBACK_DEFAULT_ABBREV;
3817                if (abbrev > GIT_SHA1_HEXSZ)
3818                        die("BUG: oid abbreviation out of range: %d", abbrev);
3819                if (abbrev)
3820                        hex[abbrev] = '\0';
3821                return hex;
3822        }
3823}
3824
3825static void fill_metainfo(struct strbuf *msg,
3826                          const char *name,
3827                          const char *other,
3828                          struct diff_filespec *one,
3829                          struct diff_filespec *two,
3830                          struct diff_options *o,
3831                          struct diff_filepair *p,
3832                          int *must_show_header,
3833                          int use_color)
3834{
3835        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3836        const char *reset = diff_get_color(use_color, DIFF_RESET);
3837        const char *line_prefix = diff_line_prefix(o);
3838
3839        *must_show_header = 1;
3840        strbuf_init(msg, PATH_MAX * 2 + 300);
3841        switch (p->status) {
3842        case DIFF_STATUS_COPIED:
3843                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3844                            line_prefix, set, similarity_index(p));
3845                strbuf_addf(msg, "%s\n%s%scopy from ",
3846                            reset,  line_prefix, set);
3847                quote_c_style(name, msg, NULL, 0);
3848                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3849                quote_c_style(other, msg, NULL, 0);
3850                strbuf_addf(msg, "%s\n", reset);
3851                break;
3852        case DIFF_STATUS_RENAMED:
3853                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3854                            line_prefix, set, similarity_index(p));
3855                strbuf_addf(msg, "%s\n%s%srename from ",
3856                            reset, line_prefix, set);
3857                quote_c_style(name, msg, NULL, 0);
3858                strbuf_addf(msg, "%s\n%s%srename to ",
3859                            reset, line_prefix, set);
3860                quote_c_style(other, msg, NULL, 0);
3861                strbuf_addf(msg, "%s\n", reset);
3862                break;
3863        case DIFF_STATUS_MODIFIED:
3864                if (p->score) {
3865                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3866                                    line_prefix,
3867                                    set, similarity_index(p), reset);
3868                        break;
3869                }
3870                /* fallthru */
3871        default:
3872                *must_show_header = 0;
3873        }
3874        if (one && two && oidcmp(&one->oid, &two->oid)) {
3875                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3876
3877                if (DIFF_OPT_TST(o, BINARY)) {
3878                        mmfile_t mf;
3879                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3880                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3881                                abbrev = 40;
3882                }
3883                strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3884                            diff_abbrev_oid(&one->oid, abbrev),
3885                            diff_abbrev_oid(&two->oid, abbrev));
3886                if (one->mode == two->mode)
3887                        strbuf_addf(msg, " %06o", one->mode);
3888                strbuf_addf(msg, "%s\n", reset);
3889        }
3890}
3891
3892static void run_diff_cmd(const char *pgm,
3893                         const char *name,
3894                         const char *other,
3895                         const char *attr_path,
3896                         struct diff_filespec *one,
3897                         struct diff_filespec *two,
3898                         struct strbuf *msg,
3899                         struct diff_options *o,
3900                         struct diff_filepair *p)
3901{
3902        const char *xfrm_msg = NULL;
3903        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3904        int must_show_header = 0;
3905
3906
3907        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3908                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3909                if (drv && drv->external)
3910                        pgm = drv->external;
3911        }
3912
3913        if (msg) {
3914                /*
3915                 * don't use colors when the header is intended for an
3916                 * external diff driver
3917                 */
3918                fill_metainfo(msg, name, other, one, two, o, p,
3919                              &must_show_header,
3920                              want_color(o->use_color) && !pgm);
3921                xfrm_msg = msg->len ? msg->buf : NULL;
3922        }
3923
3924        if (pgm) {
3925                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3926                                  complete_rewrite, o);
3927                return;
3928        }
3929        if (one && two)
3930                builtin_diff(name, other ? other : name,
3931                             one, two, xfrm_msg, must_show_header,
3932                             o, complete_rewrite);
3933        else
3934                fprintf(o->file, "* Unmerged path %s\n", name);
3935}
3936
3937static void diff_fill_oid_info(struct diff_filespec *one)
3938{
3939        if (DIFF_FILE_VALID(one)) {
3940                if (!one->oid_valid) {
3941                        struct stat st;
3942                        if (one->is_stdin) {
3943                                oidclr(&one->oid);
3944                                return;
3945                        }
3946                        if (lstat(one->path, &st) < 0)
3947                                die_errno("stat '%s'", one->path);
3948                        if (index_path(&one->oid, one->path, &st, 0))
3949                                die("cannot hash %s", one->path);
3950                }
3951        }
3952        else
3953                oidclr(&one->oid);
3954}
3955
3956static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3957{
3958        /* Strip the prefix but do not molest /dev/null and absolute paths */
3959        if (*namep && **namep != '/') {
3960                *namep += prefix_length;
3961                if (**namep == '/')
3962                        ++*namep;
3963        }
3964        if (*otherp && **otherp != '/') {
3965                *otherp += prefix_length;
3966                if (**otherp == '/')
3967                        ++*otherp;
3968        }
3969}
3970
3971static void run_diff(struct diff_filepair *p, struct diff_options *o)
3972{
3973        const char *pgm = external_diff();
3974        struct strbuf msg;
3975        struct diff_filespec *one = p->one;
3976        struct diff_filespec *two = p->two;
3977        const char *name;
3978        const char *other;
3979        const char *attr_path;
3980
3981        name  = one->path;
3982        other = (strcmp(name, two->path) ? two->path : NULL);
3983        attr_path = name;
3984        if (o->prefix_length)
3985                strip_prefix(o->prefix_length, &name, &other);
3986
3987        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3988                pgm = NULL;
3989
3990        if (DIFF_PAIR_UNMERGED(p)) {
3991                run_diff_cmd(pgm, name, NULL, attr_path,
3992                             NULL, NULL, NULL, o, p);
3993                return;
3994        }
3995
3996        diff_fill_oid_info(one);
3997        diff_fill_oid_info(two);
3998
3999        if (!pgm &&
4000            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4001            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4002                /*
4003                 * a filepair that changes between file and symlink
4004                 * needs to be split into deletion and creation.
4005                 */
4006                struct diff_filespec *null = alloc_filespec(two->path);
4007                run_diff_cmd(NULL, name, other, attr_path,
4008                             one, null, &msg, o, p);
4009                free(null);
4010                strbuf_release(&msg);
4011
4012                null = alloc_filespec(one->path);
4013                run_diff_cmd(NULL, name, other, attr_path,
4014                             null, two, &msg, o, p);
4015                free(null);
4016        }
4017        else
4018                run_diff_cmd(pgm, name, other, attr_path,
4019                             one, two, &msg, o, p);
4020
4021        strbuf_release(&msg);
4022}
4023
4024static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4025                         struct diffstat_t *diffstat)
4026{
4027        const char *name;
4028        const char *other;
4029
4030        if (DIFF_PAIR_UNMERGED(p)) {
4031                /* unmerged */
4032                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4033                return;
4034        }
4035
4036        name = p->one->path;
4037        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4038
4039        if (o->prefix_length)
4040                strip_prefix(o->prefix_length, &name, &other);
4041
4042        diff_fill_oid_info(p->one);
4043        diff_fill_oid_info(p->two);
4044
4045        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4046}
4047
4048static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4049{
4050        const char *name;
4051        const char *other;
4052        const char *attr_path;
4053
4054        if (DIFF_PAIR_UNMERGED(p)) {
4055                /* unmerged */
4056                return;
4057        }
4058
4059        name = p->one->path;
4060        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4061        attr_path = other ? other : name;
4062
4063        if (o->prefix_length)
4064                strip_prefix(o->prefix_length, &name, &other);
4065
4066        diff_fill_oid_info(p->one);
4067        diff_fill_oid_info(p->two);
4068
4069        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4070}
4071
4072void diff_setup(struct diff_options *options)
4073{
4074        memcpy(options, &default_diff_options, sizeof(*options));
4075
4076        options->file = stdout;
4077
4078        options->abbrev = DEFAULT_ABBREV;
4079        options->line_termination = '\n';
4080        options->break_opt = -1;
4081        options->rename_limit = -1;
4082        options->dirstat_permille = diff_dirstat_permille_default;
4083        options->context = diff_context_default;
4084        options->interhunkcontext = diff_interhunk_context_default;
4085        options->ws_error_highlight = ws_error_highlight_default;
4086        DIFF_OPT_SET(options, RENAME_EMPTY);
4087
4088        /* pathchange left =NULL by default */
4089        options->change = diff_change;
4090        options->add_remove = diff_addremove;
4091        options->use_color = diff_use_color_default;
4092        options->detect_rename = diff_detect_rename_default;
4093        options->xdl_opts |= diff_algorithm;
4094        if (diff_indent_heuristic)
4095                DIFF_XDL_SET(options, INDENT_HEURISTIC);
4096
4097        options->orderfile = diff_order_file_cfg;
4098
4099        if (diff_no_prefix) {
4100                options->a_prefix = options->b_prefix = "";
4101        } else if (!diff_mnemonic_prefix) {
4102                options->a_prefix = "a/";
4103                options->b_prefix = "b/";
4104        }
4105
4106        options->color_moved = diff_color_moved_default;
4107}
4108
4109void diff_setup_done(struct diff_options *options)
4110{
4111        int count = 0;
4112
4113        if (options->set_default)
4114                options->set_default(options);
4115
4116        if (options->output_format & DIFF_FORMAT_NAME)
4117                count++;
4118        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
4119                count++;
4120        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
4121                count++;
4122        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
4123                count++;
4124        if (count > 1)
4125                die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4126
4127        /*
4128         * Most of the time we can say "there are changes"
4129         * only by checking if there are changed paths, but
4130         * --ignore-whitespace* options force us to look
4131         * inside contents.
4132         */
4133
4134        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
4135            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
4136            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
4137                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
4138        else
4139                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
4140
4141        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
4142                options->detect_rename = DIFF_DETECT_COPY;
4143
4144        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
4145                options->prefix = NULL;
4146        if (options->prefix)
4147                options->prefix_length = strlen(options->prefix);
4148        else
4149                options->prefix_length = 0;
4150
4151        if (options->output_format & (DIFF_FORMAT_NAME |
4152                                      DIFF_FORMAT_NAME_STATUS |
4153                                      DIFF_FORMAT_CHECKDIFF |
4154                                      DIFF_FORMAT_NO_OUTPUT))
4155                options->output_format &= ~(DIFF_FORMAT_RAW |
4156                                            DIFF_FORMAT_NUMSTAT |
4157                                            DIFF_FORMAT_DIFFSTAT |
4158                                            DIFF_FORMAT_SHORTSTAT |
4159                                            DIFF_FORMAT_DIRSTAT |
4160                                            DIFF_FORMAT_SUMMARY |
4161                                            DIFF_FORMAT_PATCH);
4162
4163        /*
4164         * These cases always need recursive; we do not drop caller-supplied
4165         * recursive bits for other formats here.
4166         */
4167        if (options->output_format & (DIFF_FORMAT_PATCH |
4168                                      DIFF_FORMAT_NUMSTAT |
4169                                      DIFF_FORMAT_DIFFSTAT |
4170                                      DIFF_FORMAT_SHORTSTAT |
4171                                      DIFF_FORMAT_DIRSTAT |
4172                                      DIFF_FORMAT_SUMMARY |
4173                                      DIFF_FORMAT_CHECKDIFF))
4174                DIFF_OPT_SET(options, RECURSIVE);
4175        /*
4176         * Also pickaxe would not work very well if you do not say recursive
4177         */
4178        if (options->pickaxe)
4179                DIFF_OPT_SET(options, RECURSIVE);
4180        /*
4181         * When patches are generated, submodules diffed against the work tree
4182         * must be checked for dirtiness too so it can be shown in the output
4183         */
4184        if (options->output_format & DIFF_FORMAT_PATCH)
4185                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
4186
4187        if (options->detect_rename && options->rename_limit < 0)
4188                options->rename_limit = diff_rename_limit_default;
4189        if (options->setup & DIFF_SETUP_USE_CACHE) {
4190                if (!active_cache)
4191                        /* read-cache does not die even when it fails
4192                         * so it is safe for us to do this here.  Also
4193                         * it does not smudge active_cache or active_nr
4194                         * when it fails, so we do not have to worry about
4195                         * cleaning it up ourselves either.
4196                         */
4197                        read_cache();
4198        }
4199        if (40 < options->abbrev)
4200                options->abbrev = 40; /* full */
4201
4202        /*
4203         * It does not make sense to show the first hit we happened
4204         * to have found.  It does not make sense not to return with
4205         * exit code in such a case either.
4206         */
4207        if (DIFF_OPT_TST(options, QUICK)) {
4208                options->output_format = DIFF_FORMAT_NO_OUTPUT;
4209                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4210        }
4211
4212        options->diff_path_counter = 0;
4213
4214        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
4215                die(_("--follow requires exactly one pathspec"));
4216
4217        if (!options->use_color || external_diff())
4218                options->color_moved = 0;
4219}
4220
4221static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4222{
4223        char c, *eq;
4224        int len;
4225
4226        if (*arg != '-')
4227                return 0;
4228        c = *++arg;
4229        if (!c)
4230                return 0;
4231        if (c == arg_short) {
4232                c = *++arg;
4233                if (!c)
4234                        return 1;
4235                if (val && isdigit(c)) {
4236                        char *end;
4237                        int n = strtoul(arg, &end, 10);
4238                        if (*end)
4239                                return 0;
4240                        *val = n;
4241                        return 1;
4242                }
4243                return 0;
4244        }
4245        if (c != '-')
4246                return 0;
4247        arg++;
4248        eq = strchrnul(arg, '=');
4249        len = eq - arg;
4250        if (!len || strncmp(arg, arg_long, len))
4251                return 0;
4252        if (*eq) {
4253                int n;
4254                char *end;
4255                if (!isdigit(*++eq))
4256                        return 0;
4257                n = strtoul(eq, &end, 10);
4258                if (*end)
4259                        return 0;
4260                *val = n;
4261        }
4262        return 1;
4263}
4264
4265static int diff_scoreopt_parse(const char *opt);
4266
4267static inline int short_opt(char opt, const char **argv,
4268                            const char **optarg)
4269{
4270        const char *arg = argv[0];
4271        if (arg[0] != '-' || arg[1] != opt)
4272                return 0;
4273        if (arg[2] != '\0') {
4274                *optarg = arg + 2;
4275                return 1;
4276        }
4277        if (!argv[1])
4278                die("Option '%c' requires a value", opt);
4279        *optarg = argv[1];
4280        return 2;
4281}
4282
4283int parse_long_opt(const char *opt, const char **argv,
4284                   const char **optarg)
4285{
4286        const char *arg = argv[0];
4287        if (!skip_prefix(arg, "--", &arg))
4288                return 0;
4289        if (!skip_prefix(arg, opt, &arg))
4290                return 0;
4291        if (*arg == '=') { /* stuck form: --option=value */
4292                *optarg = arg + 1;
4293                return 1;
4294        }
4295        if (*arg != '\0')
4296                return 0;
4297        /* separate form: --option value */
4298        if (!argv[1])
4299                die("Option '--%s' requires a value", opt);
4300        *optarg = argv[1];
4301        return 2;
4302}
4303
4304static int stat_opt(struct diff_options *options, const char **av)
4305{
4306        const char *arg = av[0];
4307        char *end;
4308        int width = options->stat_width;
4309        int name_width = options->stat_name_width;
4310        int graph_width = options->stat_graph_width;
4311        int count = options->stat_count;
4312        int argcount = 1;
4313
4314        if (!skip_prefix(arg, "--stat", &arg))
4315                die("BUG: stat option does not begin with --stat: %s", arg);
4316        end = (char *)arg;
4317
4318        switch (*arg) {
4319        case '-':
4320                if (skip_prefix(arg, "-width", &arg)) {
4321                        if (*arg == '=')
4322                                width = strtoul(arg + 1, &end, 10);
4323                        else if (!*arg && !av[1])
4324                                die_want_option("--stat-width");
4325                        else if (!*arg) {
4326                                width = strtoul(av[1], &end, 10);
4327                                argcount = 2;
4328                        }
4329                } else if (skip_prefix(arg, "-name-width", &arg)) {
4330                        if (*arg == '=')
4331                                name_width = strtoul(arg + 1, &end, 10);
4332                        else if (!*arg && !av[1])
4333                                die_want_option("--stat-name-width");
4334                        else if (!*arg) {
4335                                name_width = strtoul(av[1], &end, 10);
4336                                argcount = 2;
4337                        }
4338                } else if (skip_prefix(arg, "-graph-width", &arg)) {
4339                        if (*arg == '=')
4340                                graph_width = strtoul(arg + 1, &end, 10);
4341                        else if (!*arg && !av[1])
4342                                die_want_option("--stat-graph-width");
4343                        else if (!*arg) {
4344                                graph_width = strtoul(av[1], &end, 10);
4345                                argcount = 2;
4346                        }
4347                } else if (skip_prefix(arg, "-count", &arg)) {
4348                        if (*arg == '=')
4349                                count = strtoul(arg + 1, &end, 10);
4350                        else if (!*arg && !av[1])
4351                                die_want_option("--stat-count");
4352                        else if (!*arg) {
4353                                count = strtoul(av[1], &end, 10);
4354                                argcount = 2;
4355                        }
4356                }
4357                break;
4358        case '=':
4359                width = strtoul(arg+1, &end, 10);
4360                if (*end == ',')
4361                        name_width = strtoul(end+1, &end, 10);
4362                if (*end == ',')
4363                        count = strtoul(end+1, &end, 10);
4364        }
4365
4366        /* Important! This checks all the error cases! */
4367        if (*end)
4368                return 0;
4369        options->output_format |= DIFF_FORMAT_DIFFSTAT;
4370        options->stat_name_width = name_width;
4371        options->stat_graph_width = graph_width;
4372        options->stat_width = width;
4373        options->stat_count = count;
4374        return argcount;
4375}
4376
4377static int parse_dirstat_opt(struct diff_options *options, const char *params)
4378{
4379        struct strbuf errmsg = STRBUF_INIT;
4380        if (parse_dirstat_params(options, params, &errmsg))
4381                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4382                    errmsg.buf);
4383        strbuf_release(&errmsg);
4384        /*
4385         * The caller knows a dirstat-related option is given from the command
4386         * line; allow it to say "return this_function();"
4387         */
4388        options->output_format |= DIFF_FORMAT_DIRSTAT;
4389        return 1;
4390}
4391
4392static int parse_submodule_opt(struct diff_options *options, const char *value)
4393{
4394        if (parse_submodule_params(options, value))
4395                die(_("Failed to parse --submodule option parameter: '%s'"),
4396                        value);
4397        return 1;
4398}
4399
4400static const char diff_status_letters[] = {
4401        DIFF_STATUS_ADDED,
4402        DIFF_STATUS_COPIED,
4403        DIFF_STATUS_DELETED,
4404        DIFF_STATUS_MODIFIED,
4405        DIFF_STATUS_RENAMED,
4406        DIFF_STATUS_TYPE_CHANGED,
4407        DIFF_STATUS_UNKNOWN,
4408        DIFF_STATUS_UNMERGED,
4409        DIFF_STATUS_FILTER_AON,
4410        DIFF_STATUS_FILTER_BROKEN,
4411        '\0',
4412};
4413
4414static unsigned int filter_bit['Z' + 1];
4415
4416static void prepare_filter_bits(void)
4417{
4418        int i;
4419
4420        if (!filter_bit[DIFF_STATUS_ADDED]) {
4421                for (i = 0; diff_status_letters[i]; i++)
4422                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
4423        }
4424}
4425
4426static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4427{
4428        return opt->filter & filter_bit[(int) status];
4429}
4430
4431static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4432{
4433        int i, optch;
4434
4435        prepare_filter_bits();
4436
4437        /*
4438         * If there is a negation e.g. 'd' in the input, and we haven't
4439         * initialized the filter field with another --diff-filter, start
4440         * from full set of bits, except for AON.
4441         */
4442        if (!opt->filter) {
4443                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4444                        if (optch < 'a' || 'z' < optch)
4445                                continue;
4446                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4447                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4448                        break;
4449                }
4450        }
4451
4452        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4453                unsigned int bit;
4454                int negate;
4455
4456                if ('a' <= optch && optch <= 'z') {
4457                        negate = 1;
4458                        optch = toupper(optch);
4459                } else {
4460                        negate = 0;
4461                }
4462
4463                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4464                if (!bit)
4465                        return optarg[i];
4466                if (negate)
4467                        opt->filter &= ~bit;
4468                else
4469                        opt->filter |= bit;
4470        }
4471        return 0;
4472}
4473
4474static void enable_patch_output(int *fmt) {
4475        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4476        *fmt |= DIFF_FORMAT_PATCH;
4477}
4478
4479static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4480{
4481        int val = parse_ws_error_highlight(arg);
4482
4483        if (val < 0) {
4484                error("unknown value after ws-error-highlight=%.*s",
4485                      -1 - val, arg);
4486                return 0;
4487        }
4488        opt->ws_error_highlight = val;
4489        return 1;
4490}
4491
4492int diff_opt_parse(struct diff_options *options,
4493                   const char **av, int ac, const char *prefix)
4494{
4495        const char *arg = av[0];
4496        const char *optarg;
4497        int argcount;
4498
4499        if (!prefix)
4500                prefix = "";
4501
4502        /* Output format options */
4503        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4504            || opt_arg(arg, 'U', "unified", &options->context))
4505                enable_patch_output(&options->output_format);
4506        else if (!strcmp(arg, "--raw"))
4507                options->output_format |= DIFF_FORMAT_RAW;
4508        else if (!strcmp(arg, "--patch-with-raw")) {
4509                enable_patch_output(&options->output_format);
4510                options->output_format |= DIFF_FORMAT_RAW;
4511        } else if (!strcmp(arg, "--numstat"))
4512                options->output_format |= DIFF_FORMAT_NUMSTAT;
4513        else if (!strcmp(arg, "--shortstat"))
4514                options->output_format |= DIFF_FORMAT_SHORTSTAT;
4515        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
4516                return parse_dirstat_opt(options, "");
4517        else if (skip_prefix(arg, "-X", &arg))
4518                return parse_dirstat_opt(options, arg);
4519        else if (skip_prefix(arg, "--dirstat=", &arg))
4520                return parse_dirstat_opt(options, arg);
4521        else if (!strcmp(arg, "--cumulative"))
4522                return parse_dirstat_opt(options, "cumulative");
4523        else if (!strcmp(arg, "--dirstat-by-file"))
4524                return parse_dirstat_opt(options, "files");
4525        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
4526                parse_dirstat_opt(options, "files");
4527                return parse_dirstat_opt(options, arg);
4528        }
4529        else if (!strcmp(arg, "--check"))
4530                options->output_format |= DIFF_FORMAT_CHECKDIFF;
4531        else if (!strcmp(arg, "--summary"))
4532                options->output_format |= DIFF_FORMAT_SUMMARY;
4533        else if (!strcmp(arg, "--patch-with-stat")) {
4534                enable_patch_output(&options->output_format);
4535                options->output_format |= DIFF_FORMAT_DIFFSTAT;
4536        } else if (!strcmp(arg, "--name-only"))
4537                options->output_format |= DIFF_FORMAT_NAME;
4538        else if (!strcmp(arg, "--name-status"))
4539                options->output_format |= DIFF_FORMAT_NAME_STATUS;
4540        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4541                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4542        else if (starts_with(arg, "--stat"))
4543                /* --stat, --stat-width, --stat-name-width, or --stat-count */
4544                return stat_opt(options, av);
4545
4546        /* renames options */
4547        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
4548                 !strcmp(arg, "--break-rewrites")) {
4549                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4550                        return error("invalid argument to -B: %s", arg+2);
4551        }
4552        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
4553                 !strcmp(arg, "--find-renames")) {
4554                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4555                        return error("invalid argument to -M: %s", arg+2);
4556                options->detect_rename = DIFF_DETECT_RENAME;
4557        }
4558        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4559                options->irreversible_delete = 1;
4560        }
4561        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
4562                 !strcmp(arg, "--find-copies")) {
4563                if (options->detect_rename == DIFF_DETECT_COPY)
4564                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4565                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4566                        return error("invalid argument to -C: %s", arg+2);
4567                options->detect_rename = DIFF_DETECT_COPY;
4568        }
4569        else if (!strcmp(arg, "--no-renames"))
4570                options->detect_rename = 0;
4571        else if (!strcmp(arg, "--rename-empty"))
4572                DIFF_OPT_SET(options, RENAME_EMPTY);
4573        else if (!strcmp(arg, "--no-rename-empty"))
4574                DIFF_OPT_CLR(options, RENAME_EMPTY);
4575        else if (!strcmp(arg, "--relative"))
4576                DIFF_OPT_SET(options, RELATIVE_NAME);
4577        else if (skip_prefix(arg, "--relative=", &arg)) {
4578                DIFF_OPT_SET(options, RELATIVE_NAME);
4579                options->prefix = arg;
4580        }
4581
4582        /* xdiff options */
4583        else if (!strcmp(arg, "--minimal"))
4584                DIFF_XDL_SET(options, NEED_MINIMAL);
4585        else if (!strcmp(arg, "--no-minimal"))
4586                DIFF_XDL_CLR(options, NEED_MINIMAL);
4587        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4588                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4589        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4590                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4591        else if (!strcmp(arg, "--ignore-space-at-eol"))
4592                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4593        else if (!strcmp(arg, "--ignore-blank-lines"))
4594                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4595        else if (!strcmp(arg, "--indent-heuristic"))
4596                DIFF_XDL_SET(options, INDENT_HEURISTIC);
4597        else if (!strcmp(arg, "--no-indent-heuristic"))
4598                DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4599        else if (!strcmp(arg, "--patience"))
4600                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4601        else if (!strcmp(arg, "--histogram"))
4602                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4603        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4604                long value = parse_algorithm_value(optarg);
4605                if (value < 0)
4606                        return error("option diff-algorithm accepts \"myers\", "
4607                                     "\"minimal\", \"patience\" and \"histogram\"");
4608                /* clear out previous settings */
4609                DIFF_XDL_CLR(options, NEED_MINIMAL);
4610                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4611                options->xdl_opts |= value;
4612                return argcount;
4613        }
4614
4615        /* flags options */
4616        else if (!strcmp(arg, "--binary")) {
4617                enable_patch_output(&options->output_format);
4618                DIFF_OPT_SET(options, BINARY);
4619        }
4620        else if (!strcmp(arg, "--full-index"))
4621                DIFF_OPT_SET(options, FULL_INDEX);
4622        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4623                DIFF_OPT_SET(options, TEXT);
4624        else if (!strcmp(arg, "-R"))
4625                DIFF_OPT_SET(options, REVERSE_DIFF);
4626        else if (!strcmp(arg, "--find-copies-harder"))
4627                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4628        else if (!strcmp(arg, "--follow"))
4629                DIFF_OPT_SET(options, FOLLOW_RENAMES);
4630        else if (!strcmp(arg, "--no-follow")) {
4631                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
4632                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
4633        } else if (!strcmp(arg, "--color"))
4634                options->use_color = 1;
4635        else if (skip_prefix(arg, "--color=", &arg)) {
4636                int value = git_config_colorbool(NULL, arg);
4637                if (value < 0)
4638                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
4639                options->use_color = value;
4640        }
4641        else if (!strcmp(arg, "--no-color"))
4642                options->use_color = 0;
4643        else if (!strcmp(arg, "--color-moved")) {
4644                if (diff_color_moved_default)
4645                        options->color_moved = diff_color_moved_default;
4646                if (options->color_moved == COLOR_MOVED_NO)
4647                        options->color_moved = COLOR_MOVED_DEFAULT;
4648        } else if (!strcmp(arg, "--no-color-moved"))
4649                options->color_moved = COLOR_MOVED_NO;
4650        else if (skip_prefix(arg, "--color-moved=", &arg)) {
4651                int cm = parse_color_moved(arg);
4652                if (cm < 0)
4653                        die("bad --color-moved argument: %s", arg);
4654                options->color_moved = cm;
4655        } else if (!strcmp(arg, "--color-words")) {
4656                options->use_color = 1;
4657                options->word_diff = DIFF_WORDS_COLOR;
4658        }
4659        else if (skip_prefix(arg, "--color-words=", &arg)) {
4660                options->use_color = 1;
4661                options->word_diff = DIFF_WORDS_COLOR;
4662                options->word_regex = arg;
4663        }
4664        else if (!strcmp(arg, "--word-diff")) {
4665                if (options->word_diff == DIFF_WORDS_NONE)
4666                        options->word_diff = DIFF_WORDS_PLAIN;
4667        }
4668        else if (skip_prefix(arg, "--word-diff=", &arg)) {
4669                if (!strcmp(arg, "plain"))
4670                        options->word_diff = DIFF_WORDS_PLAIN;
4671                else if (!strcmp(arg, "color")) {
4672                        options->use_color = 1;
4673                        options->word_diff = DIFF_WORDS_COLOR;
4674                }
4675                else if (!strcmp(arg, "porcelain"))
4676                        options->word_diff = DIFF_WORDS_PORCELAIN;
4677                else if (!strcmp(arg, "none"))
4678                        options->word_diff = DIFF_WORDS_NONE;
4679                else
4680                        die("bad --word-diff argument: %s", arg);
4681        }
4682        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4683                if (options->word_diff == DIFF_WORDS_NONE)
4684                        options->word_diff = DIFF_WORDS_PLAIN;
4685                options->word_regex = optarg;
4686                return argcount;
4687        }
4688        else if (!strcmp(arg, "--exit-code"))
4689                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4690        else if (!strcmp(arg, "--quiet"))
4691                DIFF_OPT_SET(options, QUICK);
4692        else if (!strcmp(arg, "--ext-diff"))
4693                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4694        else if (!strcmp(arg, "--no-ext-diff"))
4695                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4696        else if (!strcmp(arg, "--textconv"))
4697                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4698        else if (!strcmp(arg, "--no-textconv"))
4699                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4700        else if (!strcmp(arg, "--ignore-submodules")) {
4701                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4702                handle_ignore_submodules_arg(options, "all");
4703        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4704                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4705                handle_ignore_submodules_arg(options, arg);
4706        } else if (!strcmp(arg, "--submodule"))
4707                options->submodule_format = DIFF_SUBMODULE_LOG;
4708        else if (skip_prefix(arg, "--submodule=", &arg))
4709                return parse_submodule_opt(options, arg);
4710        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4711                return parse_ws_error_highlight_opt(options, arg);
4712        else if (!strcmp(arg, "--ita-invisible-in-index"))
4713                options->ita_invisible_in_index = 1;
4714        else if (!strcmp(arg, "--ita-visible-in-index"))
4715                options->ita_invisible_in_index = 0;
4716
4717        /* misc options */
4718        else if (!strcmp(arg, "-z"))
4719                options->line_termination = 0;
4720        else if ((argcount = short_opt('l', av, &optarg))) {
4721                options->rename_limit = strtoul(optarg, NULL, 10);
4722                return argcount;
4723        }
4724        else if ((argcount = short_opt('S', av, &optarg))) {
4725                options->pickaxe = optarg;
4726                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4727                return argcount;
4728        } else if ((argcount = short_opt('G', av, &optarg))) {
4729                options->pickaxe = optarg;
4730                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4731                return argcount;
4732        }
4733        else if (!strcmp(arg, "--pickaxe-all"))
4734                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4735        else if (!strcmp(arg, "--pickaxe-regex"))
4736                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4737        else if ((argcount = short_opt('O', av, &optarg))) {
4738                options->orderfile = prefix_filename(prefix, optarg);
4739                return argcount;
4740        }
4741        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4742                int offending = parse_diff_filter_opt(optarg, options);
4743                if (offending)
4744                        die("unknown change class '%c' in --diff-filter=%s",
4745                            offending, optarg);
4746                return argcount;
4747        }
4748        else if (!strcmp(arg, "--no-abbrev"))
4749                options->abbrev = 0;
4750        else if (!strcmp(arg, "--abbrev"))
4751                options->abbrev = DEFAULT_ABBREV;
4752        else if (skip_prefix(arg, "--abbrev=", &arg)) {
4753                options->abbrev = strtoul(arg, NULL, 10);
4754                if (options->abbrev < MINIMUM_ABBREV)
4755                        options->abbrev = MINIMUM_ABBREV;
4756                else if (40 < options->abbrev)
4757                        options->abbrev = 40;
4758        }
4759        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4760                options->a_prefix = optarg;
4761                return argcount;
4762        }
4763        else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4764                options->line_prefix = optarg;
4765                options->line_prefix_length = strlen(options->line_prefix);
4766                graph_setup_line_prefix(options);
4767                return argcount;
4768        }
4769        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4770                options->b_prefix = optarg;
4771                return argcount;
4772        }
4773        else if (!strcmp(arg, "--no-prefix"))
4774                options->a_prefix = options->b_prefix = "";
4775        else if (opt_arg(arg, '\0', "inter-hunk-context",
4776                         &options->interhunkcontext))
4777                ;
4778        else if (!strcmp(arg, "-W"))
4779                DIFF_OPT_SET(options, FUNCCONTEXT);
4780        else if (!strcmp(arg, "--function-context"))
4781                DIFF_OPT_SET(options, FUNCCONTEXT);
4782        else if (!strcmp(arg, "--no-function-context"))
4783                DIFF_OPT_CLR(options, FUNCCONTEXT);
4784        else if ((argcount = parse_long_opt("output", av, &optarg))) {
4785                char *path = prefix_filename(prefix, optarg);
4786                options->file = xfopen(path, "w");
4787                options->close_file = 1;
4788                if (options->use_color != GIT_COLOR_ALWAYS)
4789                        options->use_color = GIT_COLOR_NEVER;
4790                free(path);
4791                return argcount;
4792        } else
4793                return 0;
4794        return 1;
4795}
4796
4797int parse_rename_score(const char **cp_p)
4798{
4799        unsigned long num, scale;
4800        int ch, dot;
4801        const char *cp = *cp_p;
4802
4803        num = 0;
4804        scale = 1;
4805        dot = 0;
4806        for (;;) {
4807                ch = *cp;
4808                if ( !dot && ch == '.' ) {
4809                        scale = 1;
4810                        dot = 1;
4811                } else if ( ch == '%' ) {
4812                        scale = dot ? scale*100 : 100;
4813                        cp++;   /* % is always at the end */
4814                        break;
4815                } else if ( ch >= '0' && ch <= '9' ) {
4816                        if ( scale < 100000 ) {
4817                                scale *= 10;
4818                                num = (num*10) + (ch-'0');
4819                        }
4820                } else {
4821                        break;
4822                }
4823                cp++;
4824        }
4825        *cp_p = cp;
4826
4827        /* user says num divided by scale and we say internally that
4828         * is MAX_SCORE * num / scale.
4829         */
4830        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4831}
4832
4833static int diff_scoreopt_parse(const char *opt)
4834{
4835        int opt1, opt2, cmd;
4836
4837        if (*opt++ != '-')
4838                return -1;
4839        cmd = *opt++;
4840        if (cmd == '-') {
4841                /* convert the long-form arguments into short-form versions */
4842                if (skip_prefix(opt, "break-rewrites", &opt)) {
4843                        if (*opt == 0 || *opt++ == '=')
4844                                cmd = 'B';
4845                } else if (skip_prefix(opt, "find-copies", &opt)) {
4846                        if (*opt == 0 || *opt++ == '=')
4847                                cmd = 'C';
4848                } else if (skip_prefix(opt, "find-renames", &opt)) {
4849                        if (*opt == 0 || *opt++ == '=')
4850                                cmd = 'M';
4851                }
4852        }
4853        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4854                return -1; /* that is not a -M, -C, or -B option */
4855
4856        opt1 = parse_rename_score(&opt);
4857        if (cmd != 'B')
4858                opt2 = 0;
4859        else {
4860                if (*opt == 0)
4861                        opt2 = 0;
4862                else if (*opt != '/')
4863                        return -1; /* we expect -B80/99 or -B80 */
4864                else {
4865                        opt++;
4866                        opt2 = parse_rename_score(&opt);
4867                }
4868        }
4869        if (*opt != 0)
4870                return -1;
4871        return opt1 | (opt2 << 16);
4872}
4873
4874struct diff_queue_struct diff_queued_diff;
4875
4876void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4877{
4878        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4879        queue->queue[queue->nr++] = dp;
4880}
4881
4882struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4883                                 struct diff_filespec *one,
4884                                 struct diff_filespec *two)
4885{
4886        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4887        dp->one = one;
4888        dp->two = two;
4889        if (queue)
4890                diff_q(queue, dp);
4891        return dp;
4892}
4893
4894void diff_free_filepair(struct diff_filepair *p)
4895{
4896        free_filespec(p->one);
4897        free_filespec(p->two);
4898        free(p);
4899}
4900
4901const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4902{
4903        int abblen;
4904        const char *abbrev;
4905
4906        if (len == GIT_SHA1_HEXSZ)
4907                return oid_to_hex(oid);
4908
4909        abbrev = diff_abbrev_oid(oid, len);
4910        abblen = strlen(abbrev);
4911
4912        /*
4913         * In well-behaved cases, where the abbbreviated result is the
4914         * same as the requested length, append three dots after the
4915         * abbreviation (hence the whole logic is limited to the case
4916         * where abblen < 37); when the actual abbreviated result is a
4917         * bit longer than the requested length, we reduce the number
4918         * of dots so that they match the well-behaved ones.  However,
4919         * if the actual abbreviation is longer than the requested
4920         * length by more than three, we give up on aligning, and add
4921         * three dots anyway, to indicate that the output is not the
4922         * full object name.  Yes, this may be suboptimal, but this
4923         * appears only in "diff --raw --abbrev" output and it is not
4924         * worth the effort to change it now.  Note that this would
4925         * likely to work fine when the automatic sizing of default
4926         * abbreviation length is used--we would be fed -1 in "len" in
4927         * that case, and will end up always appending three-dots, but
4928         * the automatic sizing is supposed to give abblen that ensures
4929         * uniqueness across all objects (statistically speaking).
4930         */
4931        if (abblen < GIT_SHA1_HEXSZ - 3) {
4932                static char hex[GIT_MAX_HEXSZ + 1];
4933                if (len < abblen && abblen <= len + 2)
4934                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4935                else
4936                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4937                return hex;
4938        }
4939
4940        return oid_to_hex(oid);
4941}
4942
4943static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4944{
4945        int line_termination = opt->line_termination;
4946        int inter_name_termination = line_termination ? '\t' : '\0';
4947
4948        fprintf(opt->file, "%s", diff_line_prefix(opt));
4949        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4950                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4951                        diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4952                fprintf(opt->file, "%s ",
4953                        diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4954        }
4955        if (p->score) {
4956                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4957                        inter_name_termination);
4958        } else {
4959                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4960        }
4961
4962        if (p->status == DIFF_STATUS_COPIED ||
4963            p->status == DIFF_STATUS_RENAMED) {
4964                const char *name_a, *name_b;
4965                name_a = p->one->path;
4966                name_b = p->two->path;
4967                strip_prefix(opt->prefix_length, &name_a, &name_b);
4968                write_name_quoted(name_a, opt->file, inter_name_termination);
4969                write_name_quoted(name_b, opt->file, line_termination);
4970        } else {
4971                const char *name_a, *name_b;
4972                name_a = p->one->mode ? p->one->path : p->two->path;
4973                name_b = NULL;
4974                strip_prefix(opt->prefix_length, &name_a, &name_b);
4975                write_name_quoted(name_a, opt->file, line_termination);
4976        }
4977}
4978
4979int diff_unmodified_pair(struct diff_filepair *p)
4980{
4981        /* This function is written stricter than necessary to support
4982         * the currently implemented transformers, but the idea is to
4983         * let transformers to produce diff_filepairs any way they want,
4984         * and filter and clean them up here before producing the output.
4985         */
4986        struct diff_filespec *one = p->one, *two = p->two;
4987
4988        if (DIFF_PAIR_UNMERGED(p))
4989                return 0; /* unmerged is interesting */
4990
4991        /* deletion, addition, mode or type change
4992         * and rename are all interesting.
4993         */
4994        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4995            DIFF_PAIR_MODE_CHANGED(p) ||
4996            strcmp(one->path, two->path))
4997                return 0;
4998
4999        /* both are valid and point at the same path.  that is, we are
5000         * dealing with a change.
5001         */
5002        if (one->oid_valid && two->oid_valid &&
5003            !oidcmp(&one->oid, &two->oid) &&
5004            !one->dirty_submodule && !two->dirty_submodule)
5005                return 1; /* no change */
5006        if (!one->oid_valid && !two->oid_valid)
5007                return 1; /* both look at the same file on the filesystem. */
5008        return 0;
5009}
5010
5011static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5012{
5013        if (diff_unmodified_pair(p))
5014                return;
5015
5016        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5017            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5018                return; /* no tree diffs in patch format */
5019
5020        run_diff(p, o);
5021}
5022
5023static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5024                            struct diffstat_t *diffstat)
5025{
5026        if (diff_unmodified_pair(p))
5027                return;
5028
5029        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5030            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5031                return; /* no useful stat for tree diffs */
5032
5033        run_diffstat(p, o, diffstat);
5034}
5035
5036static void diff_flush_checkdiff(struct diff_filepair *p,
5037                struct diff_options *o)
5038{
5039        if (diff_unmodified_pair(p))
5040                return;
5041
5042        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5043            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5044                return; /* nothing to check in tree diffs */
5045
5046        run_checkdiff(p, o);
5047}
5048
5049int diff_queue_is_empty(void)
5050{
5051        struct diff_queue_struct *q = &diff_queued_diff;
5052        int i;
5053        for (i = 0; i < q->nr; i++)
5054                if (!diff_unmodified_pair(q->queue[i]))
5055                        return 0;
5056        return 1;
5057}
5058
5059#if DIFF_DEBUG
5060void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5061{
5062        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5063                x, one ? one : "",
5064                s->path,
5065                DIFF_FILE_VALID(s) ? "valid" : "invalid",
5066                s->mode,
5067                s->oid_valid ? oid_to_hex(&s->oid) : "");
5068        fprintf(stderr, "queue[%d] %s size %lu\n",
5069                x, one ? one : "",
5070                s->size);
5071}
5072
5073void diff_debug_filepair(const struct diff_filepair *p, int i)
5074{
5075        diff_debug_filespec(p->one, i, "one");
5076        diff_debug_filespec(p->two, i, "two");
5077        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5078                p->score, p->status ? p->status : '?',
5079                p->one->rename_used, p->broken_pair);
5080}
5081
5082void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5083{
5084        int i;
5085        if (msg)
5086                fprintf(stderr, "%s\n", msg);
5087        fprintf(stderr, "q->nr = %d\n", q->nr);
5088        for (i = 0; i < q->nr; i++) {
5089                struct diff_filepair *p = q->queue[i];
5090                diff_debug_filepair(p, i);
5091        }
5092}
5093#endif
5094
5095static void diff_resolve_rename_copy(void)
5096{
5097        int i;
5098        struct diff_filepair *p;
5099        struct diff_queue_struct *q = &diff_queued_diff;
5100
5101        diff_debug_queue("resolve-rename-copy", q);
5102
5103        for (i = 0; i < q->nr; i++) {
5104                p = q->queue[i];
5105                p->status = 0; /* undecided */
5106                if (DIFF_PAIR_UNMERGED(p))
5107                        p->status = DIFF_STATUS_UNMERGED;
5108                else if (!DIFF_FILE_VALID(p->one))
5109                        p->status = DIFF_STATUS_ADDED;
5110                else if (!DIFF_FILE_VALID(p->two))
5111                        p->status = DIFF_STATUS_DELETED;
5112                else if (DIFF_PAIR_TYPE_CHANGED(p))
5113                        p->status = DIFF_STATUS_TYPE_CHANGED;
5114
5115                /* from this point on, we are dealing with a pair
5116                 * whose both sides are valid and of the same type, i.e.
5117                 * either in-place edit or rename/copy edit.
5118                 */
5119                else if (DIFF_PAIR_RENAME(p)) {
5120                        /*
5121                         * A rename might have re-connected a broken
5122                         * pair up, causing the pathnames to be the
5123                         * same again. If so, that's not a rename at
5124                         * all, just a modification..
5125                         *
5126                         * Otherwise, see if this source was used for
5127                         * multiple renames, in which case we decrement
5128                         * the count, and call it a copy.
5129                         */
5130                        if (!strcmp(p->one->path, p->two->path))
5131                                p->status = DIFF_STATUS_MODIFIED;
5132                        else if (--p->one->rename_used > 0)
5133                                p->status = DIFF_STATUS_COPIED;
5134                        else
5135                                p->status = DIFF_STATUS_RENAMED;
5136                }
5137                else if (oidcmp(&p->one->oid, &p->two->oid) ||
5138                         p->one->mode != p->two->mode ||
5139                         p->one->dirty_submodule ||
5140                         p->two->dirty_submodule ||
5141                         is_null_oid(&p->one->oid))
5142                        p->status = DIFF_STATUS_MODIFIED;
5143                else {
5144                        /* This is a "no-change" entry and should not
5145                         * happen anymore, but prepare for broken callers.
5146                         */
5147                        error("feeding unmodified %s to diffcore",
5148                              p->one->path);
5149                        p->status = DIFF_STATUS_UNKNOWN;
5150                }
5151        }
5152        diff_debug_queue("resolve-rename-copy done", q);
5153}
5154
5155static int check_pair_status(struct diff_filepair *p)
5156{
5157        switch (p->status) {
5158        case DIFF_STATUS_UNKNOWN:
5159                return 0;
5160        case 0:
5161                die("internal error in diff-resolve-rename-copy");
5162        default:
5163                return 1;
5164        }
5165}
5166
5167static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5168{
5169        int fmt = opt->output_format;
5170
5171        if (fmt & DIFF_FORMAT_CHECKDIFF)
5172                diff_flush_checkdiff(p, opt);
5173        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5174                diff_flush_raw(p, opt);
5175        else if (fmt & DIFF_FORMAT_NAME) {
5176                const char *name_a, *name_b;
5177                name_a = p->two->path;
5178                name_b = NULL;
5179                strip_prefix(opt->prefix_length, &name_a, &name_b);
5180                fprintf(opt->file, "%s", diff_line_prefix(opt));
5181                write_name_quoted(name_a, opt->file, opt->line_termination);
5182        }
5183}
5184
5185static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5186{
5187        struct strbuf sb = STRBUF_INIT;
5188        if (fs->mode)
5189                strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5190        else
5191                strbuf_addf(&sb, " %s ", newdelete);
5192
5193        quote_c_style(fs->path, &sb, NULL, 0);
5194        strbuf_addch(&sb, '\n');
5195        emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5196                         sb.buf, sb.len, 0);
5197        strbuf_release(&sb);
5198}
5199
5200static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5201                int show_name)
5202{
5203        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5204                struct strbuf sb = STRBUF_INIT;
5205                strbuf_addf(&sb, " mode change %06o => %06o",
5206                            p->one->mode, p->two->mode);
5207                if (show_name) {
5208                        strbuf_addch(&sb, ' ');
5209                        quote_c_style(p->two->path, &sb, NULL, 0);
5210                }
5211                strbuf_addch(&sb, '\n');
5212                emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5213                                 sb.buf, sb.len, 0);
5214                strbuf_release(&sb);
5215        }
5216}
5217
5218static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5219                struct diff_filepair *p)
5220{
5221        struct strbuf sb = STRBUF_INIT;
5222        char *names = pprint_rename(p->one->path, p->two->path);
5223        strbuf_addf(&sb, " %s %s (%d%%)\n",
5224                        renamecopy, names, similarity_index(p));
5225        free(names);
5226        emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5227                                 sb.buf, sb.len, 0);
5228        show_mode_change(opt, p, 0);
5229        strbuf_release(&sb);
5230}
5231
5232static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5233{
5234        switch(p->status) {
5235        case DIFF_STATUS_DELETED:
5236                show_file_mode_name(opt, "delete", p->one);
5237                break;
5238        case DIFF_STATUS_ADDED:
5239                show_file_mode_name(opt, "create", p->two);
5240                break;
5241        case DIFF_STATUS_COPIED:
5242                show_rename_copy(opt, "copy", p);
5243                break;
5244        case DIFF_STATUS_RENAMED:
5245                show_rename_copy(opt, "rename", p);
5246                break;
5247        default:
5248                if (p->score) {
5249                        struct strbuf sb = STRBUF_INIT;
5250                        strbuf_addstr(&sb, " rewrite ");
5251                        quote_c_style(p->two->path, &sb, NULL, 0);
5252                        strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5253                        emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5254                                         sb.buf, sb.len, 0);
5255                        strbuf_release(&sb);
5256                }
5257                show_mode_change(opt, p, !p->score);
5258                break;
5259        }
5260}
5261
5262struct patch_id_t {
5263        git_SHA_CTX *ctx;
5264        int patchlen;
5265};
5266
5267static int remove_space(char *line, int len)
5268{
5269        int i;
5270        char *dst = line;
5271        unsigned char c;
5272
5273        for (i = 0; i < len; i++)
5274                if (!isspace((c = line[i])))
5275                        *dst++ = c;
5276
5277        return dst - line;
5278}
5279
5280static void patch_id_consume(void *priv, char *line, unsigned long len)
5281{
5282        struct patch_id_t *data = priv;
5283        int new_len;
5284
5285        /* Ignore line numbers when computing the SHA1 of the patch */
5286        if (starts_with(line, "@@ -"))
5287                return;
5288
5289        new_len = remove_space(line, len);
5290
5291        git_SHA1_Update(data->ctx, line, new_len);
5292        data->patchlen += new_len;
5293}
5294
5295static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5296{
5297        git_SHA1_Update(ctx, str, strlen(str));
5298}
5299
5300static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5301{
5302        /* large enough for 2^32 in octal */
5303        char buf[12];
5304        int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5305        git_SHA1_Update(ctx, buf, len);
5306}
5307
5308/* returns 0 upon success, and writes result into sha1 */
5309static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5310{
5311        struct diff_queue_struct *q = &diff_queued_diff;
5312        int i;
5313        git_SHA_CTX ctx;
5314        struct patch_id_t data;
5315
5316        git_SHA1_Init(&ctx);
5317        memset(&data, 0, sizeof(struct patch_id_t));
5318        data.ctx = &ctx;
5319
5320        for (i = 0; i < q->nr; i++) {
5321                xpparam_t xpp;
5322                xdemitconf_t xecfg;
5323                mmfile_t mf1, mf2;
5324                struct diff_filepair *p = q->queue[i];
5325                int len1, len2;
5326
5327                memset(&xpp, 0, sizeof(xpp));
5328                memset(&xecfg, 0, sizeof(xecfg));
5329                if (p->status == 0)
5330                        return error("internal diff status error");
5331                if (p->status == DIFF_STATUS_UNKNOWN)
5332                        continue;
5333                if (diff_unmodified_pair(p))
5334                        continue;
5335                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5336                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5337                        continue;
5338                if (DIFF_PAIR_UNMERGED(p))
5339                        continue;
5340
5341                diff_fill_oid_info(p->one);
5342                diff_fill_oid_info(p->two);
5343
5344                len1 = remove_space(p->one->path, strlen(p->one->path));
5345                len2 = remove_space(p->two->path, strlen(p->two->path));
5346                patch_id_add_string(&ctx, "diff--git");
5347                patch_id_add_string(&ctx, "a/");
5348                git_SHA1_Update(&ctx, p->one->path, len1);
5349                patch_id_add_string(&ctx, "b/");
5350                git_SHA1_Update(&ctx, p->two->path, len2);
5351
5352                if (p->one->mode == 0) {
5353                        patch_id_add_string(&ctx, "newfilemode");
5354                        patch_id_add_mode(&ctx, p->two->mode);
5355                        patch_id_add_string(&ctx, "---/dev/null");
5356                        patch_id_add_string(&ctx, "+++b/");
5357                        git_SHA1_Update(&ctx, p->two->path, len2);
5358                } else if (p->two->mode == 0) {
5359                        patch_id_add_string(&ctx, "deletedfilemode");
5360                        patch_id_add_mode(&ctx, p->one->mode);
5361                        patch_id_add_string(&ctx, "---a/");
5362                        git_SHA1_Update(&ctx, p->one->path, len1);
5363                        patch_id_add_string(&ctx, "+++/dev/null");
5364                } else {
5365                        patch_id_add_string(&ctx, "---a/");
5366                        git_SHA1_Update(&ctx, p->one->path, len1);
5367                        patch_id_add_string(&ctx, "+++b/");
5368                        git_SHA1_Update(&ctx, p->two->path, len2);
5369                }
5370
5371                if (diff_header_only)
5372                        continue;
5373
5374                if (fill_mmfile(&mf1, p->one) < 0 ||
5375                    fill_mmfile(&mf2, p->two) < 0)
5376                        return error("unable to read files to diff");
5377
5378                if (diff_filespec_is_binary(p->one) ||
5379                    diff_filespec_is_binary(p->two)) {
5380                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5381                                        GIT_SHA1_HEXSZ);
5382                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5383                                        GIT_SHA1_HEXSZ);
5384                        continue;
5385                }
5386
5387                xpp.flags = 0;
5388                xecfg.ctxlen = 3;
5389                xecfg.flags = 0;
5390                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5391                                  &xpp, &xecfg))
5392                        return error("unable to generate patch-id diff for %s",
5393                                     p->one->path);
5394        }
5395
5396        git_SHA1_Final(oid->hash, &ctx);
5397        return 0;
5398}
5399
5400int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5401{
5402        struct diff_queue_struct *q = &diff_queued_diff;
5403        int i;
5404        int result = diff_get_patch_id(options, oid, diff_header_only);
5405
5406        for (i = 0; i < q->nr; i++)
5407                diff_free_filepair(q->queue[i]);
5408
5409        free(q->queue);
5410        DIFF_QUEUE_CLEAR(q);
5411
5412        return result;
5413}
5414
5415static int is_summary_empty(const struct diff_queue_struct *q)
5416{
5417        int i;
5418
5419        for (i = 0; i < q->nr; i++) {
5420                const struct diff_filepair *p = q->queue[i];
5421
5422                switch (p->status) {
5423                case DIFF_STATUS_DELETED:
5424                case DIFF_STATUS_ADDED:
5425                case DIFF_STATUS_COPIED:
5426                case DIFF_STATUS_RENAMED:
5427                        return 0;
5428                default:
5429                        if (p->score)
5430                                return 0;
5431                        if (p->one->mode && p->two->mode &&
5432                            p->one->mode != p->two->mode)
5433                                return 0;
5434                        break;
5435                }
5436        }
5437        return 1;
5438}
5439
5440static const char rename_limit_warning[] =
5441N_("inexact rename detection was skipped due to too many files.");
5442
5443static const char degrade_cc_to_c_warning[] =
5444N_("only found copies from modified paths due to too many files.");
5445
5446static const char rename_limit_advice[] =
5447N_("you may want to set your %s variable to at least "
5448   "%d and retry the command.");
5449
5450void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5451{
5452        if (degraded_cc)
5453                warning(_(degrade_cc_to_c_warning));
5454        else if (needed)
5455                warning(_(rename_limit_warning));
5456        else
5457                return;
5458        if (0 < needed && needed < 32767)
5459                warning(_(rename_limit_advice), varname, needed);
5460}
5461
5462static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5463{
5464        int i;
5465        static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5466        struct diff_queue_struct *q = &diff_queued_diff;
5467
5468        if (WSEH_NEW & WS_RULE_MASK)
5469                die("BUG: WS rules bit mask overlaps with diff symbol flags");
5470
5471        if (o->color_moved)
5472                o->emitted_symbols = &esm;
5473
5474        for (i = 0; i < q->nr; i++) {
5475                struct diff_filepair *p = q->queue[i];
5476                if (check_pair_status(p))
5477                        diff_flush_patch(p, o);
5478        }
5479
5480        if (o->emitted_symbols) {
5481                if (o->color_moved) {
5482                        struct hashmap add_lines, del_lines;
5483
5484                        hashmap_init(&del_lines,
5485                                     (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5486                        hashmap_init(&add_lines,
5487                                     (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5488
5489                        add_lines_to_move_detection(o, &add_lines, &del_lines);
5490                        mark_color_as_moved(o, &add_lines, &del_lines);
5491                        if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5492                                dim_moved_lines(o);
5493
5494                        hashmap_free(&add_lines, 0);
5495                        hashmap_free(&del_lines, 0);
5496                }
5497
5498                for (i = 0; i < esm.nr; i++)
5499                        emit_diff_symbol_from_struct(o, &esm.buf[i]);
5500
5501                for (i = 0; i < esm.nr; i++)
5502                        free((void *)esm.buf[i].line);
5503        }
5504        esm.nr = 0;
5505}
5506
5507void diff_flush(struct diff_options *options)
5508{
5509        struct diff_queue_struct *q = &diff_queued_diff;
5510        int i, output_format = options->output_format;
5511        int separator = 0;
5512        int dirstat_by_line = 0;
5513
5514        /*
5515         * Order: raw, stat, summary, patch
5516         * or:    name/name-status/checkdiff (other bits clear)
5517         */
5518        if (!q->nr)
5519                goto free_queue;
5520
5521        if (output_format & (DIFF_FORMAT_RAW |
5522                             DIFF_FORMAT_NAME |
5523                             DIFF_FORMAT_NAME_STATUS |
5524                             DIFF_FORMAT_CHECKDIFF)) {
5525                for (i = 0; i < q->nr; i++) {
5526                        struct diff_filepair *p = q->queue[i];
5527                        if (check_pair_status(p))
5528                                flush_one_pair(p, options);
5529                }
5530                separator++;
5531        }
5532
5533        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
5534                dirstat_by_line = 1;
5535
5536        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5537            dirstat_by_line) {
5538                struct diffstat_t diffstat;
5539
5540                memset(&diffstat, 0, sizeof(struct diffstat_t));
5541                for (i = 0; i < q->nr; i++) {
5542                        struct diff_filepair *p = q->queue[i];
5543                        if (check_pair_status(p))
5544                                diff_flush_stat(p, options, &diffstat);
5545                }
5546                if (output_format & DIFF_FORMAT_NUMSTAT)
5547                        show_numstat(&diffstat, options);
5548                if (output_format & DIFF_FORMAT_DIFFSTAT)
5549                        show_stats(&diffstat, options);
5550                if (output_format & DIFF_FORMAT_SHORTSTAT)
5551                        show_shortstats(&diffstat, options);
5552                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5553                        show_dirstat_by_line(&diffstat, options);
5554                free_diffstat_info(&diffstat);
5555                separator++;
5556        }
5557        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5558                show_dirstat(options);
5559
5560        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5561                for (i = 0; i < q->nr; i++) {
5562                        diff_summary(options, q->queue[i]);
5563                }
5564                separator++;
5565        }
5566
5567        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5568            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
5569            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
5570                /*
5571                 * run diff_flush_patch for the exit status. setting
5572                 * options->file to /dev/null should be safe, because we
5573                 * aren't supposed to produce any output anyway.
5574                 */
5575                if (options->close_file)
5576                        fclose(options->file);
5577                options->file = xfopen("/dev/null", "w");
5578                options->close_file = 1;
5579                options->color_moved = 0;
5580                for (i = 0; i < q->nr; i++) {
5581                        struct diff_filepair *p = q->queue[i];
5582                        if (check_pair_status(p))
5583                                diff_flush_patch(p, options);
5584                        if (options->found_changes)
5585                                break;
5586                }
5587        }
5588
5589        if (output_format & DIFF_FORMAT_PATCH) {
5590                if (separator) {
5591                        emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5592                        if (options->stat_sep)
5593                                /* attach patch instead of inline */
5594                                emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5595                                                 NULL, 0, 0);
5596                }
5597
5598                diff_flush_patch_all_file_pairs(options);
5599        }
5600
5601        if (output_format & DIFF_FORMAT_CALLBACK)
5602                options->format_callback(q, options, options->format_callback_data);
5603
5604        for (i = 0; i < q->nr; i++)
5605                diff_free_filepair(q->queue[i]);
5606free_queue:
5607        free(q->queue);
5608        DIFF_QUEUE_CLEAR(q);
5609        if (options->close_file)
5610                fclose(options->file);
5611
5612        /*
5613         * Report the content-level differences with HAS_CHANGES;
5614         * diff_addremove/diff_change does not set the bit when
5615         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5616         */
5617        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
5618                if (options->found_changes)
5619                        DIFF_OPT_SET(options, HAS_CHANGES);
5620                else
5621                        DIFF_OPT_CLR(options, HAS_CHANGES);
5622        }
5623}
5624
5625static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5626{
5627        return (((p->status == DIFF_STATUS_MODIFIED) &&
5628                 ((p->score &&
5629                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5630                  (!p->score &&
5631                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5632                ((p->status != DIFF_STATUS_MODIFIED) &&
5633                 filter_bit_tst(p->status, options)));
5634}
5635
5636static void diffcore_apply_filter(struct diff_options *options)
5637{
5638        int i;
5639        struct diff_queue_struct *q = &diff_queued_diff;
5640        struct diff_queue_struct outq;
5641
5642        DIFF_QUEUE_CLEAR(&outq);
5643
5644        if (!options->filter)
5645                return;
5646
5647        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5648                int found;
5649                for (i = found = 0; !found && i < q->nr; i++) {
5650                        if (match_filter(options, q->queue[i]))
5651                                found++;
5652                }
5653                if (found)
5654                        return;
5655
5656                /* otherwise we will clear the whole queue
5657                 * by copying the empty outq at the end of this
5658                 * function, but first clear the current entries
5659                 * in the queue.
5660                 */
5661                for (i = 0; i < q->nr; i++)
5662                        diff_free_filepair(q->queue[i]);
5663        }
5664        else {
5665                /* Only the matching ones */
5666                for (i = 0; i < q->nr; i++) {
5667                        struct diff_filepair *p = q->queue[i];
5668                        if (match_filter(options, p))
5669                                diff_q(&outq, p);
5670                        else
5671                                diff_free_filepair(p);
5672                }
5673        }
5674        free(q->queue);
5675        *q = outq;
5676}
5677
5678/* Check whether two filespecs with the same mode and size are identical */
5679static int diff_filespec_is_identical(struct diff_filespec *one,
5680                                      struct diff_filespec *two)
5681{
5682        if (S_ISGITLINK(one->mode))
5683                return 0;
5684        if (diff_populate_filespec(one, 0))
5685                return 0;
5686        if (diff_populate_filespec(two, 0))
5687                return 0;
5688        return !memcmp(one->data, two->data, one->size);
5689}
5690
5691static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5692{
5693        if (p->done_skip_stat_unmatch)
5694                return p->skip_stat_unmatch_result;
5695
5696        p->done_skip_stat_unmatch = 1;
5697        p->skip_stat_unmatch_result = 0;
5698        /*
5699         * 1. Entries that come from stat info dirtiness
5700         *    always have both sides (iow, not create/delete),
5701         *    one side of the object name is unknown, with
5702         *    the same mode and size.  Keep the ones that
5703         *    do not match these criteria.  They have real
5704         *    differences.
5705         *
5706         * 2. At this point, the file is known to be modified,
5707         *    with the same mode and size, and the object
5708         *    name of one side is unknown.  Need to inspect
5709         *    the identical contents.
5710         */
5711        if (!DIFF_FILE_VALID(p->one) || /* (1) */
5712            !DIFF_FILE_VALID(p->two) ||
5713            (p->one->oid_valid && p->two->oid_valid) ||
5714            (p->one->mode != p->two->mode) ||
5715            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5716            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5717            (p->one->size != p->two->size) ||
5718            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5719                p->skip_stat_unmatch_result = 1;
5720        return p->skip_stat_unmatch_result;
5721}
5722
5723static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5724{
5725        int i;
5726        struct diff_queue_struct *q = &diff_queued_diff;
5727        struct diff_queue_struct outq;
5728        DIFF_QUEUE_CLEAR(&outq);
5729
5730        for (i = 0; i < q->nr; i++) {
5731                struct diff_filepair *p = q->queue[i];
5732
5733                if (diff_filespec_check_stat_unmatch(p))
5734                        diff_q(&outq, p);
5735                else {
5736                        /*
5737                         * The caller can subtract 1 from skip_stat_unmatch
5738                         * to determine how many paths were dirty only
5739                         * due to stat info mismatch.
5740                         */
5741                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5742                                diffopt->skip_stat_unmatch++;
5743                        diff_free_filepair(p);
5744                }
5745        }
5746        free(q->queue);
5747        *q = outq;
5748}
5749
5750static int diffnamecmp(const void *a_, const void *b_)
5751{
5752        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5753        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5754        const char *name_a, *name_b;
5755
5756        name_a = a->one ? a->one->path : a->two->path;
5757        name_b = b->one ? b->one->path : b->two->path;
5758        return strcmp(name_a, name_b);
5759}
5760
5761void diffcore_fix_diff_index(struct diff_options *options)
5762{
5763        struct diff_queue_struct *q = &diff_queued_diff;
5764        QSORT(q->queue, q->nr, diffnamecmp);
5765}
5766
5767void diffcore_std(struct diff_options *options)
5768{
5769        /* NOTE please keep the following in sync with diff_tree_combined() */
5770        if (options->skip_stat_unmatch)
5771                diffcore_skip_stat_unmatch(options);
5772        if (!options->found_follow) {
5773                /* See try_to_follow_renames() in tree-diff.c */
5774                if (options->break_opt != -1)
5775                        diffcore_break(options->break_opt);
5776                if (options->detect_rename)
5777                        diffcore_rename(options);
5778                if (options->break_opt != -1)
5779                        diffcore_merge_broken();
5780        }
5781        if (options->pickaxe)
5782                diffcore_pickaxe(options);
5783        if (options->orderfile)
5784                diffcore_order(options->orderfile);
5785        if (!options->found_follow)
5786                /* See try_to_follow_renames() in tree-diff.c */
5787                diff_resolve_rename_copy();
5788        diffcore_apply_filter(options);
5789
5790        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5791                DIFF_OPT_SET(options, HAS_CHANGES);
5792        else
5793                DIFF_OPT_CLR(options, HAS_CHANGES);
5794
5795        options->found_follow = 0;
5796}
5797
5798int diff_result_code(struct diff_options *opt, int status)
5799{
5800        int result = 0;
5801
5802        diff_warn_rename_limit("diff.renameLimit",
5803                               opt->needed_rename_limit,
5804                               opt->degraded_cc_to_c);
5805        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5806            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5807                return status;
5808        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5809            DIFF_OPT_TST(opt, HAS_CHANGES))
5810                result |= 01;
5811        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5812            DIFF_OPT_TST(opt, CHECK_FAILED))
5813                result |= 02;
5814        return result;
5815}
5816
5817int diff_can_quit_early(struct diff_options *opt)
5818{
5819        return (DIFF_OPT_TST(opt, QUICK) &&
5820                !opt->filter &&
5821                DIFF_OPT_TST(opt, HAS_CHANGES));
5822}
5823
5824/*
5825 * Shall changes to this submodule be ignored?
5826 *
5827 * Submodule changes can be configured to be ignored separately for each path,
5828 * but that configuration can be overridden from the command line.
5829 */
5830static int is_submodule_ignored(const char *path, struct diff_options *options)
5831{
5832        int ignored = 0;
5833        unsigned orig_flags = options->flags;
5834        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5835                set_diffopt_flags_from_submodule_config(options, path);
5836        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5837                ignored = 1;
5838        options->flags = orig_flags;
5839        return ignored;
5840}
5841
5842void diff_addremove(struct diff_options *options,
5843                    int addremove, unsigned mode,
5844                    const struct object_id *oid,
5845                    int oid_valid,
5846                    const char *concatpath, unsigned dirty_submodule)
5847{
5848        struct diff_filespec *one, *two;
5849
5850        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5851                return;
5852
5853        /* This may look odd, but it is a preparation for
5854         * feeding "there are unchanged files which should
5855         * not produce diffs, but when you are doing copy
5856         * detection you would need them, so here they are"
5857         * entries to the diff-core.  They will be prefixed
5858         * with something like '=' or '*' (I haven't decided
5859         * which but should not make any difference).
5860         * Feeding the same new and old to diff_change()
5861         * also has the same effect.
5862         * Before the final output happens, they are pruned after
5863         * merged into rename/copy pairs as appropriate.
5864         */
5865        if (DIFF_OPT_TST(options, REVERSE_DIFF))
5866                addremove = (addremove == '+' ? '-' :
5867                             addremove == '-' ? '+' : addremove);
5868
5869        if (options->prefix &&
5870            strncmp(concatpath, options->prefix, options->prefix_length))
5871                return;
5872
5873        one = alloc_filespec(concatpath);
5874        two = alloc_filespec(concatpath);
5875
5876        if (addremove != '+')
5877                fill_filespec(one, oid, oid_valid, mode);
5878        if (addremove != '-') {
5879                fill_filespec(two, oid, oid_valid, mode);
5880                two->dirty_submodule = dirty_submodule;
5881        }
5882
5883        diff_queue(&diff_queued_diff, one, two);
5884        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5885                DIFF_OPT_SET(options, HAS_CHANGES);
5886}
5887
5888void diff_change(struct diff_options *options,
5889                 unsigned old_mode, unsigned new_mode,
5890                 const struct object_id *old_oid,
5891                 const struct object_id *new_oid,
5892                 int old_oid_valid, int new_oid_valid,
5893                 const char *concatpath,
5894                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5895{
5896        struct diff_filespec *one, *two;
5897        struct diff_filepair *p;
5898
5899        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5900            is_submodule_ignored(concatpath, options))
5901                return;
5902
5903        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5904                SWAP(old_mode, new_mode);
5905                SWAP(old_oid, new_oid);
5906                SWAP(old_oid_valid, new_oid_valid);
5907                SWAP(old_dirty_submodule, new_dirty_submodule);
5908        }
5909
5910        if (options->prefix &&
5911            strncmp(concatpath, options->prefix, options->prefix_length))
5912                return;
5913
5914        one = alloc_filespec(concatpath);
5915        two = alloc_filespec(concatpath);
5916        fill_filespec(one, old_oid, old_oid_valid, old_mode);
5917        fill_filespec(two, new_oid, new_oid_valid, new_mode);
5918        one->dirty_submodule = old_dirty_submodule;
5919        two->dirty_submodule = new_dirty_submodule;
5920        p = diff_queue(&diff_queued_diff, one, two);
5921
5922        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5923                return;
5924
5925        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5926            !diff_filespec_check_stat_unmatch(p))
5927                return;
5928
5929        DIFF_OPT_SET(options, HAS_CHANGES);
5930}
5931
5932struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5933{
5934        struct diff_filepair *pair;
5935        struct diff_filespec *one, *two;
5936
5937        if (options->prefix &&
5938            strncmp(path, options->prefix, options->prefix_length))
5939                return NULL;
5940
5941        one = alloc_filespec(path);
5942        two = alloc_filespec(path);
5943        pair = diff_queue(&diff_queued_diff, one, two);
5944        pair->is_unmerged = 1;
5945        return pair;
5946}
5947
5948static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5949                size_t *outsize)
5950{
5951        struct diff_tempfile *temp;
5952        const char *argv[3];
5953        const char **arg = argv;
5954        struct child_process child = CHILD_PROCESS_INIT;
5955        struct strbuf buf = STRBUF_INIT;
5956        int err = 0;
5957
5958        temp = prepare_temp_file(spec->path, spec);
5959        *arg++ = pgm;
5960        *arg++ = temp->name;
5961        *arg = NULL;
5962
5963        child.use_shell = 1;
5964        child.argv = argv;
5965        child.out = -1;
5966        if (start_command(&child)) {
5967                remove_tempfile();
5968                return NULL;
5969        }
5970
5971        if (strbuf_read(&buf, child.out, 0) < 0)
5972                err = error("error reading from textconv command '%s'", pgm);
5973        close(child.out);
5974
5975        if (finish_command(&child) || err) {
5976                strbuf_release(&buf);
5977                remove_tempfile();
5978                return NULL;
5979        }
5980        remove_tempfile();
5981
5982        return strbuf_detach(&buf, outsize);
5983}
5984
5985size_t fill_textconv(struct userdiff_driver *driver,
5986                     struct diff_filespec *df,
5987                     char **outbuf)
5988{
5989        size_t size;
5990
5991        if (!driver) {
5992                if (!DIFF_FILE_VALID(df)) {
5993                        *outbuf = "";
5994                        return 0;
5995                }
5996                if (diff_populate_filespec(df, 0))
5997                        die("unable to read files to diff");
5998                *outbuf = df->data;
5999                return df->size;
6000        }
6001
6002        if (!driver->textconv)
6003                die("BUG: fill_textconv called with non-textconv driver");
6004
6005        if (driver->textconv_cache && df->oid_valid) {
6006                *outbuf = notes_cache_get(driver->textconv_cache,
6007                                          &df->oid,
6008                                          &size);
6009                if (*outbuf)
6010                        return size;
6011        }
6012
6013        *outbuf = run_textconv(driver->textconv, df, &size);
6014        if (!*outbuf)
6015                die("unable to read files to diff");
6016
6017        if (driver->textconv_cache && df->oid_valid) {
6018                /* ignore errors, as we might be in a readonly repository */
6019                notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6020                                size);
6021                /*
6022                 * we could save up changes and flush them all at the end,
6023                 * but we would need an extra call after all diffing is done.
6024                 * Since generating a cache entry is the slow path anyway,
6025                 * this extra overhead probably isn't a big deal.
6026                 */
6027                notes_cache_write(driver->textconv_cache);
6028        }
6029
6030        return size;
6031}
6032
6033int textconv_object(const char *path,
6034                    unsigned mode,
6035                    const struct object_id *oid,
6036                    int oid_valid,
6037                    char **buf,
6038                    unsigned long *buf_size)
6039{
6040        struct diff_filespec *df;
6041        struct userdiff_driver *textconv;
6042
6043        df = alloc_filespec(path);
6044        fill_filespec(df, oid, oid_valid, mode);
6045        textconv = get_textconv(df);
6046        if (!textconv) {
6047                free_filespec(df);
6048                return 0;
6049        }
6050
6051        *buf_size = fill_textconv(textconv, df, buf);
6052        free_filespec(df);
6053        return 1;
6054}
6055
6056void setup_diff_pager(struct diff_options *opt)
6057{
6058        /*
6059         * If the user asked for our exit code, then either they want --quiet
6060         * or --exit-code. We should definitely not bother with a pager in the
6061         * former case, as we will generate no output. Since we still properly
6062         * report our exit code even when a pager is run, we _could_ run a
6063         * pager with --exit-code. But since we have not done so historically,
6064         * and because it is easy to find people oneline advising "git diff
6065         * --exit-code" in hooks and other scripts, we do not do so.
6066         */
6067        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
6068            check_pager_config("diff") != 0)
6069                setup_pager();
6070}