b2b2a19fcf3eb3c0c591b76f54280fff2f3c5bd8
   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 "ll-merge.h"
  20#include "string-list.h"
  21#include "argv-array.h"
  22#include "graph.h"
  23
  24#ifdef NO_FAST_WORKING_DIRECTORY
  25#define FAST_WORKING_DIRECTORY 0
  26#else
  27#define FAST_WORKING_DIRECTORY 1
  28#endif
  29
  30static int diff_detect_rename_default;
  31static int diff_indent_heuristic = 1;
  32static int diff_rename_limit_default = 400;
  33static int diff_suppress_blank_empty;
  34static int diff_use_color_default = -1;
  35static int diff_context_default = 3;
  36static int diff_interhunk_context_default;
  37static const char *diff_word_regex_cfg;
  38static const char *external_diff_cmd_cfg;
  39static const char *diff_order_file_cfg;
  40int diff_auto_refresh_index = 1;
  41static int diff_mnemonic_prefix;
  42static int diff_no_prefix;
  43static int diff_stat_graph_width;
  44static int diff_dirstat_permille_default = 30;
  45static struct diff_options default_diff_options;
  46static long diff_algorithm;
  47static unsigned ws_error_highlight_default = WSEH_NEW;
  48
  49static char diff_colors[][COLOR_MAXLEN] = {
  50        GIT_COLOR_RESET,
  51        GIT_COLOR_NORMAL,       /* CONTEXT */
  52        GIT_COLOR_BOLD,         /* METAINFO */
  53        GIT_COLOR_CYAN,         /* FRAGINFO */
  54        GIT_COLOR_RED,          /* OLD */
  55        GIT_COLOR_GREEN,        /* NEW */
  56        GIT_COLOR_YELLOW,       /* COMMIT */
  57        GIT_COLOR_BG_RED,       /* WHITESPACE */
  58        GIT_COLOR_NORMAL,       /* FUNCINFO */
  59};
  60
  61static NORETURN void die_want_option(const char *option_name)
  62{
  63        die(_("option '%s' requires a value"), option_name);
  64}
  65
  66static int parse_diff_color_slot(const char *var)
  67{
  68        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  69                return DIFF_CONTEXT;
  70        if (!strcasecmp(var, "meta"))
  71                return DIFF_METAINFO;
  72        if (!strcasecmp(var, "frag"))
  73                return DIFF_FRAGINFO;
  74        if (!strcasecmp(var, "old"))
  75                return DIFF_FILE_OLD;
  76        if (!strcasecmp(var, "new"))
  77                return DIFF_FILE_NEW;
  78        if (!strcasecmp(var, "commit"))
  79                return DIFF_COMMIT;
  80        if (!strcasecmp(var, "whitespace"))
  81                return DIFF_WHITESPACE;
  82        if (!strcasecmp(var, "func"))
  83                return DIFF_FUNCINFO;
  84        return -1;
  85}
  86
  87static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  88                                struct strbuf *errmsg)
  89{
  90        char *params_copy = xstrdup(params_string);
  91        struct string_list params = STRING_LIST_INIT_NODUP;
  92        int ret = 0;
  93        int i;
  94
  95        if (*params_copy)
  96                string_list_split_in_place(&params, params_copy, ',', -1);
  97        for (i = 0; i < params.nr; i++) {
  98                const char *p = params.items[i].string;
  99                if (!strcmp(p, "changes")) {
 100                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 101                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 102                } else if (!strcmp(p, "lines")) {
 103                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 104                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 105                } else if (!strcmp(p, "files")) {
 106                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 107                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 108                } else if (!strcmp(p, "noncumulative")) {
 109                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 110                } else if (!strcmp(p, "cumulative")) {
 111                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 112                } else if (isdigit(*p)) {
 113                        char *end;
 114                        int permille = strtoul(p, &end, 10) * 10;
 115                        if (*end == '.' && isdigit(*++end)) {
 116                                /* only use first digit */
 117                                permille += *end - '0';
 118                                /* .. and ignore any further digits */
 119                                while (isdigit(*++end))
 120                                        ; /* nothing */
 121                        }
 122                        if (!*end)
 123                                options->dirstat_permille = permille;
 124                        else {
 125                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 126                                            p);
 127                                ret++;
 128                        }
 129                } else {
 130                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 131                        ret++;
 132                }
 133
 134        }
 135        string_list_clear(&params, 0);
 136        free(params_copy);
 137        return ret;
 138}
 139
 140static int parse_submodule_params(struct diff_options *options, const char *value)
 141{
 142        if (!strcmp(value, "log"))
 143                options->submodule_format = DIFF_SUBMODULE_LOG;
 144        else if (!strcmp(value, "short"))
 145                options->submodule_format = DIFF_SUBMODULE_SHORT;
 146        else if (!strcmp(value, "diff"))
 147                options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 148        else
 149                return -1;
 150        return 0;
 151}
 152
 153static int git_config_rename(const char *var, const char *value)
 154{
 155        if (!value)
 156                return DIFF_DETECT_RENAME;
 157        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 158                return  DIFF_DETECT_COPY;
 159        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 160}
 161
 162long parse_algorithm_value(const char *value)
 163{
 164        if (!value)
 165                return -1;
 166        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 167                return 0;
 168        else if (!strcasecmp(value, "minimal"))
 169                return XDF_NEED_MINIMAL;
 170        else if (!strcasecmp(value, "patience"))
 171                return XDF_PATIENCE_DIFF;
 172        else if (!strcasecmp(value, "histogram"))
 173                return XDF_HISTOGRAM_DIFF;
 174        return -1;
 175}
 176
 177static int parse_one_token(const char **arg, const char *token)
 178{
 179        const char *rest;
 180        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 181                *arg = rest;
 182                return 1;
 183        }
 184        return 0;
 185}
 186
 187static int parse_ws_error_highlight(const char *arg)
 188{
 189        const char *orig_arg = arg;
 190        unsigned val = 0;
 191
 192        while (*arg) {
 193                if (parse_one_token(&arg, "none"))
 194                        val = 0;
 195                else if (parse_one_token(&arg, "default"))
 196                        val = WSEH_NEW;
 197                else if (parse_one_token(&arg, "all"))
 198                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 199                else if (parse_one_token(&arg, "new"))
 200                        val |= WSEH_NEW;
 201                else if (parse_one_token(&arg, "old"))
 202                        val |= WSEH_OLD;
 203                else if (parse_one_token(&arg, "context"))
 204                        val |= WSEH_CONTEXT;
 205                else {
 206                        return -1 - (int)(arg - orig_arg);
 207                }
 208                if (*arg)
 209                        arg++;
 210        }
 211        return val;
 212}
 213
 214/*
 215 * These are to give UI layer defaults.
 216 * The core-level commands such as git-diff-files should
 217 * never be affected by the setting of diff.renames
 218 * the user happens to have in the configuration file.
 219 */
 220void init_diff_ui_defaults(void)
 221{
 222        diff_detect_rename_default = 1;
 223}
 224
 225int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 226{
 227        if (!strcmp(var, "diff.indentheuristic"))
 228                diff_indent_heuristic = git_config_bool(var, value);
 229        return 0;
 230}
 231
 232int git_diff_ui_config(const char *var, const char *value, void *cb)
 233{
 234        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 235                diff_use_color_default = git_config_colorbool(var, value);
 236                return 0;
 237        }
 238        if (!strcmp(var, "diff.context")) {
 239                diff_context_default = git_config_int(var, value);
 240                if (diff_context_default < 0)
 241                        return -1;
 242                return 0;
 243        }
 244        if (!strcmp(var, "diff.interhunkcontext")) {
 245                diff_interhunk_context_default = git_config_int(var, value);
 246                if (diff_interhunk_context_default < 0)
 247                        return -1;
 248                return 0;
 249        }
 250        if (!strcmp(var, "diff.renames")) {
 251                diff_detect_rename_default = git_config_rename(var, value);
 252                return 0;
 253        }
 254        if (!strcmp(var, "diff.autorefreshindex")) {
 255                diff_auto_refresh_index = git_config_bool(var, value);
 256                return 0;
 257        }
 258        if (!strcmp(var, "diff.mnemonicprefix")) {
 259                diff_mnemonic_prefix = git_config_bool(var, value);
 260                return 0;
 261        }
 262        if (!strcmp(var, "diff.noprefix")) {
 263                diff_no_prefix = git_config_bool(var, value);
 264                return 0;
 265        }
 266        if (!strcmp(var, "diff.statgraphwidth")) {
 267                diff_stat_graph_width = git_config_int(var, value);
 268                return 0;
 269        }
 270        if (!strcmp(var, "diff.external"))
 271                return git_config_string(&external_diff_cmd_cfg, var, value);
 272        if (!strcmp(var, "diff.wordregex"))
 273                return git_config_string(&diff_word_regex_cfg, var, value);
 274        if (!strcmp(var, "diff.orderfile"))
 275                return git_config_pathname(&diff_order_file_cfg, var, value);
 276
 277        if (!strcmp(var, "diff.ignoresubmodules"))
 278                handle_ignore_submodules_arg(&default_diff_options, value);
 279
 280        if (!strcmp(var, "diff.submodule")) {
 281                if (parse_submodule_params(&default_diff_options, value))
 282                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 283                                value);
 284                return 0;
 285        }
 286
 287        if (!strcmp(var, "diff.algorithm")) {
 288                diff_algorithm = parse_algorithm_value(value);
 289                if (diff_algorithm < 0)
 290                        return -1;
 291                return 0;
 292        }
 293
 294        if (!strcmp(var, "diff.wserrorhighlight")) {
 295                int val = parse_ws_error_highlight(value);
 296                if (val < 0)
 297                        return -1;
 298                ws_error_highlight_default = val;
 299                return 0;
 300        }
 301
 302        if (git_color_config(var, value, cb) < 0)
 303                return -1;
 304
 305        return git_diff_basic_config(var, value, cb);
 306}
 307
 308int git_diff_basic_config(const char *var, const char *value, void *cb)
 309{
 310        const char *name;
 311
 312        if (!strcmp(var, "diff.renamelimit")) {
 313                diff_rename_limit_default = git_config_int(var, value);
 314                return 0;
 315        }
 316
 317        if (userdiff_config(var, value) < 0)
 318                return -1;
 319
 320        if (skip_prefix(var, "diff.color.", &name) ||
 321            skip_prefix(var, "color.diff.", &name)) {
 322                int slot = parse_diff_color_slot(name);
 323                if (slot < 0)
 324                        return 0;
 325                if (!value)
 326                        return config_error_nonbool(var);
 327                return color_parse(value, diff_colors[slot]);
 328        }
 329
 330        /* like GNU diff's --suppress-blank-empty option  */
 331        if (!strcmp(var, "diff.suppressblankempty") ||
 332                        /* for backwards compatibility */
 333                        !strcmp(var, "diff.suppress-blank-empty")) {
 334                diff_suppress_blank_empty = git_config_bool(var, value);
 335                return 0;
 336        }
 337
 338        if (!strcmp(var, "diff.dirstat")) {
 339                struct strbuf errmsg = STRBUF_INIT;
 340                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 341                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 342                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 343                                errmsg.buf);
 344                strbuf_release(&errmsg);
 345                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 346                return 0;
 347        }
 348
 349        if (starts_with(var, "submodule."))
 350                return parse_submodule_config_option(var, value);
 351
 352        if (git_diff_heuristic_config(var, value, cb) < 0)
 353                return -1;
 354
 355        return git_default_config(var, value, cb);
 356}
 357
 358static char *quote_two(const char *one, const char *two)
 359{
 360        int need_one = quote_c_style(one, NULL, NULL, 1);
 361        int need_two = quote_c_style(two, NULL, NULL, 1);
 362        struct strbuf res = STRBUF_INIT;
 363
 364        if (need_one + need_two) {
 365                strbuf_addch(&res, '"');
 366                quote_c_style(one, &res, NULL, 1);
 367                quote_c_style(two, &res, NULL, 1);
 368                strbuf_addch(&res, '"');
 369        } else {
 370                strbuf_addstr(&res, one);
 371                strbuf_addstr(&res, two);
 372        }
 373        return strbuf_detach(&res, NULL);
 374}
 375
 376static const char *external_diff(void)
 377{
 378        static const char *external_diff_cmd = NULL;
 379        static int done_preparing = 0;
 380
 381        if (done_preparing)
 382                return external_diff_cmd;
 383        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 384        if (!external_diff_cmd)
 385                external_diff_cmd = external_diff_cmd_cfg;
 386        done_preparing = 1;
 387        return external_diff_cmd;
 388}
 389
 390/*
 391 * Keep track of files used for diffing. Sometimes such an entry
 392 * refers to a temporary file, sometimes to an existing file, and
 393 * sometimes to "/dev/null".
 394 */
 395static struct diff_tempfile {
 396        /*
 397         * filename external diff should read from, or NULL if this
 398         * entry is currently not in use:
 399         */
 400        const char *name;
 401
 402        char hex[GIT_MAX_HEXSZ + 1];
 403        char mode[10];
 404
 405        /*
 406         * If this diff_tempfile instance refers to a temporary file,
 407         * this tempfile object is used to manage its lifetime.
 408         */
 409        struct tempfile tempfile;
 410} diff_temp[2];
 411
 412typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 413
 414struct emit_callback {
 415        int color_diff;
 416        unsigned ws_rule;
 417        int blank_at_eof_in_preimage;
 418        int blank_at_eof_in_postimage;
 419        int lno_in_preimage;
 420        int lno_in_postimage;
 421        sane_truncate_fn truncate;
 422        const char **label_path;
 423        struct diff_words_data *diff_words;
 424        struct diff_options *opt;
 425        struct strbuf *header;
 426};
 427
 428static int count_lines(const char *data, int size)
 429{
 430        int count, ch, completely_empty = 1, nl_just_seen = 0;
 431        count = 0;
 432        while (0 < size--) {
 433                ch = *data++;
 434                if (ch == '\n') {
 435                        count++;
 436                        nl_just_seen = 1;
 437                        completely_empty = 0;
 438                }
 439                else {
 440                        nl_just_seen = 0;
 441                        completely_empty = 0;
 442                }
 443        }
 444        if (completely_empty)
 445                return 0;
 446        if (!nl_just_seen)
 447                count++; /* no trailing newline */
 448        return count;
 449}
 450
 451static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 452{
 453        if (!DIFF_FILE_VALID(one)) {
 454                mf->ptr = (char *)""; /* does not matter */
 455                mf->size = 0;
 456                return 0;
 457        }
 458        else if (diff_populate_filespec(one, 0))
 459                return -1;
 460
 461        mf->ptr = one->data;
 462        mf->size = one->size;
 463        return 0;
 464}
 465
 466/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 467static unsigned long diff_filespec_size(struct diff_filespec *one)
 468{
 469        if (!DIFF_FILE_VALID(one))
 470                return 0;
 471        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 472        return one->size;
 473}
 474
 475static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 476{
 477        char *ptr = mf->ptr;
 478        long size = mf->size;
 479        int cnt = 0;
 480
 481        if (!size)
 482                return cnt;
 483        ptr += size - 1; /* pointing at the very end */
 484        if (*ptr != '\n')
 485                ; /* incomplete line */
 486        else
 487                ptr--; /* skip the last LF */
 488        while (mf->ptr < ptr) {
 489                char *prev_eol;
 490                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 491                        if (*prev_eol == '\n')
 492                                break;
 493                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 494                        break;
 495                cnt++;
 496                ptr = prev_eol - 1;
 497        }
 498        return cnt;
 499}
 500
 501static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 502                               struct emit_callback *ecbdata)
 503{
 504        int l1, l2, at;
 505        unsigned ws_rule = ecbdata->ws_rule;
 506        l1 = count_trailing_blank(mf1, ws_rule);
 507        l2 = count_trailing_blank(mf2, ws_rule);
 508        if (l2 <= l1) {
 509                ecbdata->blank_at_eof_in_preimage = 0;
 510                ecbdata->blank_at_eof_in_postimage = 0;
 511                return;
 512        }
 513        at = count_lines(mf1->ptr, mf1->size);
 514        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 515
 516        at = count_lines(mf2->ptr, mf2->size);
 517        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 518}
 519
 520static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 521                        int first, const char *line, int len)
 522{
 523        int has_trailing_newline, has_trailing_carriage_return;
 524        int nofirst;
 525        FILE *file = o->file;
 526
 527        fputs(diff_line_prefix(o), file);
 528
 529        if (len == 0) {
 530                has_trailing_newline = (first == '\n');
 531                has_trailing_carriage_return = (!has_trailing_newline &&
 532                                                (first == '\r'));
 533                nofirst = has_trailing_newline || has_trailing_carriage_return;
 534        } else {
 535                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 536                if (has_trailing_newline)
 537                        len--;
 538                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 539                if (has_trailing_carriage_return)
 540                        len--;
 541                nofirst = 0;
 542        }
 543
 544        if (len || !nofirst) {
 545                fputs(set, file);
 546                if (!nofirst)
 547                        fputc(first, file);
 548                fwrite(line, len, 1, file);
 549                fputs(reset, file);
 550        }
 551        if (has_trailing_carriage_return)
 552                fputc('\r', file);
 553        if (has_trailing_newline)
 554                fputc('\n', file);
 555}
 556
 557static void emit_line(struct diff_options *o, const char *set, const char *reset,
 558                      const char *line, int len)
 559{
 560        emit_line_0(o, set, reset, line[0], line+1, len-1);
 561}
 562
 563enum diff_symbol {
 564        DIFF_SYMBOL_WORDS_PORCELAIN,
 565        DIFF_SYMBOL_WORDS,
 566        DIFF_SYMBOL_CONTEXT,
 567        DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 568        DIFF_SYMBOL_PLUS,
 569        DIFF_SYMBOL_MINUS,
 570        DIFF_SYMBOL_NO_LF_EOF,
 571        DIFF_SYMBOL_CONTEXT_FRAGINFO,
 572        DIFF_SYMBOL_CONTEXT_MARKER,
 573        DIFF_SYMBOL_SEPARATOR
 574};
 575/*
 576 * Flags for content lines:
 577 * 0..12 are whitespace rules
 578 * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 579 * 16 is marking if the line is blank at EOF
 580 */
 581#define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF (1<<16)
 582#define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 583
 584static void emit_line_ws_markup(struct diff_options *o,
 585                                const char *set, const char *reset,
 586                                const char *line, int len, char sign,
 587                                unsigned ws_rule, int blank_at_eof)
 588{
 589        const char *ws = NULL;
 590
 591        if (o->ws_error_highlight & ws_rule) {
 592                ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 593                if (!*ws)
 594                        ws = NULL;
 595        }
 596
 597        if (!ws)
 598                emit_line_0(o, set, reset, sign, line, len);
 599        else if (blank_at_eof)
 600                /* Blank line at EOF - paint '+' as well */
 601                emit_line_0(o, ws, reset, sign, line, len);
 602        else {
 603                /* Emit just the prefix, then the rest. */
 604                emit_line_0(o, set, reset, sign, "", 0);
 605                ws_check_emit(line, len, ws_rule,
 606                              o->file, set, reset, ws);
 607        }
 608}
 609
 610static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 611                             const char *line, int len, unsigned flags)
 612{
 613        static const char *nneof = " No newline at end of file\n";
 614        const char *context, *reset, *set;
 615        switch (s) {
 616        case DIFF_SYMBOL_NO_LF_EOF:
 617                context = diff_get_color_opt(o, DIFF_CONTEXT);
 618                reset = diff_get_color_opt(o, DIFF_RESET);
 619                putc('\n', o->file);
 620                emit_line_0(o, context, reset, '\\',
 621                            nneof, strlen(nneof));
 622                break;
 623        case DIFF_SYMBOL_CONTEXT_FRAGINFO:
 624                emit_line(o, "", "", line, len);
 625                break;
 626        case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
 627        case DIFF_SYMBOL_CONTEXT_MARKER:
 628                context = diff_get_color_opt(o, DIFF_CONTEXT);
 629                reset = diff_get_color_opt(o, DIFF_RESET);
 630                emit_line(o, context, reset, line, len);
 631                break;
 632        case DIFF_SYMBOL_SEPARATOR:
 633                fprintf(o->file, "%s%c",
 634                        diff_line_prefix(o),
 635                        o->line_termination);
 636                break;
 637        case DIFF_SYMBOL_CONTEXT:
 638                set = diff_get_color_opt(o, DIFF_CONTEXT);
 639                reset = diff_get_color_opt(o, DIFF_RESET);
 640                emit_line_ws_markup(o, set, reset, line, len, ' ',
 641                                    flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
 642                break;
 643        case DIFF_SYMBOL_PLUS:
 644                set = diff_get_color_opt(o, DIFF_FILE_NEW);
 645                reset = diff_get_color_opt(o, DIFF_RESET);
 646                emit_line_ws_markup(o, set, reset, line, len, '+',
 647                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK,
 648                                    flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
 649                break;
 650        case DIFF_SYMBOL_MINUS:
 651                set = diff_get_color_opt(o, DIFF_FILE_OLD);
 652                reset = diff_get_color_opt(o, DIFF_RESET);
 653                emit_line_ws_markup(o, set, reset, line, len, '-',
 654                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
 655                break;
 656        case DIFF_SYMBOL_WORDS_PORCELAIN:
 657                context = diff_get_color_opt(o, DIFF_CONTEXT);
 658                reset = diff_get_color_opt(o, DIFF_RESET);
 659                emit_line(o, context, reset, line, len);
 660                fputs("~\n", o->file);
 661                break;
 662        case DIFF_SYMBOL_WORDS:
 663                context = diff_get_color_opt(o, DIFF_CONTEXT);
 664                reset = diff_get_color_opt(o, DIFF_RESET);
 665                /*
 666                 * Skip the prefix character, if any.  With
 667                 * diff_suppress_blank_empty, there may be
 668                 * none.
 669                 */
 670                if (line[0] != '\n') {
 671                        line++;
 672                        len--;
 673                }
 674                emit_line(o, context, reset, line, len);
 675                break;
 676        default:
 677                die("BUG: unknown diff symbol");
 678        }
 679}
 680
 681static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 682{
 683        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 684              ecbdata->blank_at_eof_in_preimage &&
 685              ecbdata->blank_at_eof_in_postimage &&
 686              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 687              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 688                return 0;
 689        return ws_blank_line(line, len, ecbdata->ws_rule);
 690}
 691
 692static void emit_add_line(const char *reset,
 693                          struct emit_callback *ecbdata,
 694                          const char *line, int len)
 695{
 696        unsigned flags = WSEH_NEW | ecbdata->ws_rule;
 697        if (new_blank_line_at_eof(ecbdata, line, len))
 698                flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
 699
 700        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
 701}
 702
 703static void emit_del_line(const char *reset,
 704                          struct emit_callback *ecbdata,
 705                          const char *line, int len)
 706{
 707        unsigned flags = WSEH_OLD | ecbdata->ws_rule;
 708        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
 709}
 710
 711static void emit_context_line(const char *reset,
 712                              struct emit_callback *ecbdata,
 713                              const char *line, int len)
 714{
 715        unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
 716        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
 717}
 718
 719static void emit_hunk_header(struct emit_callback *ecbdata,
 720                             const char *line, int len)
 721{
 722        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 723        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 724        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 725        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 726        static const char atat[2] = { '@', '@' };
 727        const char *cp, *ep;
 728        struct strbuf msgbuf = STRBUF_INIT;
 729        int org_len = len;
 730        int i = 1;
 731
 732        /*
 733         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 734         * it always is at least 10 bytes long.
 735         */
 736        if (len < 10 ||
 737            memcmp(line, atat, 2) ||
 738            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 739                emit_diff_symbol(ecbdata->opt,
 740                                 DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
 741                return;
 742        }
 743        ep += 2; /* skip over @@ */
 744
 745        /* The hunk header in fraginfo color */
 746        strbuf_addstr(&msgbuf, frag);
 747        strbuf_add(&msgbuf, line, ep - line);
 748        strbuf_addstr(&msgbuf, reset);
 749
 750        /*
 751         * trailing "\r\n"
 752         */
 753        for ( ; i < 3; i++)
 754                if (line[len - i] == '\r' || line[len - i] == '\n')
 755                        len--;
 756
 757        /* blank before the func header */
 758        for (cp = ep; ep - line < len; ep++)
 759                if (*ep != ' ' && *ep != '\t')
 760                        break;
 761        if (ep != cp) {
 762                strbuf_addstr(&msgbuf, context);
 763                strbuf_add(&msgbuf, cp, ep - cp);
 764                strbuf_addstr(&msgbuf, reset);
 765        }
 766
 767        if (ep < line + len) {
 768                strbuf_addstr(&msgbuf, func);
 769                strbuf_add(&msgbuf, ep, line + len - ep);
 770                strbuf_addstr(&msgbuf, reset);
 771        }
 772
 773        strbuf_add(&msgbuf, line + len, org_len - len);
 774        strbuf_complete_line(&msgbuf);
 775        emit_diff_symbol(ecbdata->opt,
 776                         DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
 777        strbuf_release(&msgbuf);
 778}
 779
 780static struct diff_tempfile *claim_diff_tempfile(void) {
 781        int i;
 782        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 783                if (!diff_temp[i].name)
 784                        return diff_temp + i;
 785        die("BUG: diff is failing to clean up its tempfiles");
 786}
 787
 788static void remove_tempfile(void)
 789{
 790        int i;
 791        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 792                if (is_tempfile_active(&diff_temp[i].tempfile))
 793                        delete_tempfile(&diff_temp[i].tempfile);
 794                diff_temp[i].name = NULL;
 795        }
 796}
 797
 798static void print_line_count(FILE *file, int count)
 799{
 800        switch (count) {
 801        case 0:
 802                fprintf(file, "0,0");
 803                break;
 804        case 1:
 805                fprintf(file, "1");
 806                break;
 807        default:
 808                fprintf(file, "1,%d", count);
 809                break;
 810        }
 811}
 812
 813static void emit_rewrite_lines(struct emit_callback *ecb,
 814                               int prefix, const char *data, int size)
 815{
 816        const char *endp = NULL;
 817        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 818
 819        while (0 < size) {
 820                int len;
 821
 822                endp = memchr(data, '\n', size);
 823                len = endp ? (endp - data + 1) : size;
 824                if (prefix != '+') {
 825                        ecb->lno_in_preimage++;
 826                        emit_del_line(reset, ecb, data, len);
 827                } else {
 828                        ecb->lno_in_postimage++;
 829                        emit_add_line(reset, ecb, data, len);
 830                }
 831                size -= len;
 832                data += len;
 833        }
 834        if (!endp)
 835                emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
 836}
 837
 838static void emit_rewrite_diff(const char *name_a,
 839                              const char *name_b,
 840                              struct diff_filespec *one,
 841                              struct diff_filespec *two,
 842                              struct userdiff_driver *textconv_one,
 843                              struct userdiff_driver *textconv_two,
 844                              struct diff_options *o)
 845{
 846        int lc_a, lc_b;
 847        const char *name_a_tab, *name_b_tab;
 848        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 849        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 850        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 851        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 852        const char *a_prefix, *b_prefix;
 853        char *data_one, *data_two;
 854        size_t size_one, size_two;
 855        struct emit_callback ecbdata;
 856        const char *line_prefix = diff_line_prefix(o);
 857
 858        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 859                a_prefix = o->b_prefix;
 860                b_prefix = o->a_prefix;
 861        } else {
 862                a_prefix = o->a_prefix;
 863                b_prefix = o->b_prefix;
 864        }
 865
 866        name_a += (*name_a == '/');
 867        name_b += (*name_b == '/');
 868        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 869        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 870
 871        strbuf_reset(&a_name);
 872        strbuf_reset(&b_name);
 873        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 874        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 875
 876        size_one = fill_textconv(textconv_one, one, &data_one);
 877        size_two = fill_textconv(textconv_two, two, &data_two);
 878
 879        memset(&ecbdata, 0, sizeof(ecbdata));
 880        ecbdata.color_diff = want_color(o->use_color);
 881        ecbdata.ws_rule = whitespace_rule(name_b);
 882        ecbdata.opt = o;
 883        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 884                mmfile_t mf1, mf2;
 885                mf1.ptr = (char *)data_one;
 886                mf2.ptr = (char *)data_two;
 887                mf1.size = size_one;
 888                mf2.size = size_two;
 889                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 890        }
 891        ecbdata.lno_in_preimage = 1;
 892        ecbdata.lno_in_postimage = 1;
 893
 894        lc_a = count_lines(data_one, size_one);
 895        lc_b = count_lines(data_two, size_two);
 896        fprintf(o->file,
 897                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 898                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 899                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 900                line_prefix, fraginfo);
 901        if (!o->irreversible_delete)
 902                print_line_count(o->file, lc_a);
 903        else
 904                fprintf(o->file, "?,?");
 905        fprintf(o->file, " +");
 906        print_line_count(o->file, lc_b);
 907        fprintf(o->file, " @@%s\n", reset);
 908        if (lc_a && !o->irreversible_delete)
 909                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 910        if (lc_b)
 911                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 912        if (textconv_one)
 913                free((char *)data_one);
 914        if (textconv_two)
 915                free((char *)data_two);
 916}
 917
 918struct diff_words_buffer {
 919        mmfile_t text;
 920        long alloc;
 921        struct diff_words_orig {
 922                const char *begin, *end;
 923        } *orig;
 924        int orig_nr, orig_alloc;
 925};
 926
 927static void diff_words_append(char *line, unsigned long len,
 928                struct diff_words_buffer *buffer)
 929{
 930        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 931        line++;
 932        len--;
 933        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 934        buffer->text.size += len;
 935        buffer->text.ptr[buffer->text.size] = '\0';
 936}
 937
 938struct diff_words_style_elem {
 939        const char *prefix;
 940        const char *suffix;
 941        const char *color; /* NULL; filled in by the setup code if
 942                            * color is enabled */
 943};
 944
 945struct diff_words_style {
 946        enum diff_words_type type;
 947        struct diff_words_style_elem new, old, ctx;
 948        const char *newline;
 949};
 950
 951static struct diff_words_style diff_words_styles[] = {
 952        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 953        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 954        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 955};
 956
 957struct diff_words_data {
 958        struct diff_words_buffer minus, plus;
 959        const char *current_plus;
 960        int last_minus;
 961        struct diff_options *opt;
 962        regex_t *word_regex;
 963        enum diff_words_type type;
 964        struct diff_words_style *style;
 965};
 966
 967static int fn_out_diff_words_write_helper(FILE *fp,
 968                                          struct diff_words_style_elem *st_el,
 969                                          const char *newline,
 970                                          size_t count, const char *buf,
 971                                          const char *line_prefix)
 972{
 973        int print = 0;
 974
 975        while (count) {
 976                char *p = memchr(buf, '\n', count);
 977                if (print)
 978                        fputs(line_prefix, fp);
 979                if (p != buf) {
 980                        if (st_el->color && fputs(st_el->color, fp) < 0)
 981                                return -1;
 982                        if (fputs(st_el->prefix, fp) < 0 ||
 983                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 984                            fputs(st_el->suffix, fp) < 0)
 985                                return -1;
 986                        if (st_el->color && *st_el->color
 987                            && fputs(GIT_COLOR_RESET, fp) < 0)
 988                                return -1;
 989                }
 990                if (!p)
 991                        return 0;
 992                if (fputs(newline, fp) < 0)
 993                        return -1;
 994                count -= p + 1 - buf;
 995                buf = p + 1;
 996                print = 1;
 997        }
 998        return 0;
 999}
1000
1001/*
1002 * '--color-words' algorithm can be described as:
1003 *
1004 *   1. collect the minus/plus lines of a diff hunk, divided into
1005 *      minus-lines and plus-lines;
1006 *
1007 *   2. break both minus-lines and plus-lines into words and
1008 *      place them into two mmfile_t with one word for each line;
1009 *
1010 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1011 *
1012 * And for the common parts of the both file, we output the plus side text.
1013 * diff_words->current_plus is used to trace the current position of the plus file
1014 * which printed. diff_words->last_minus is used to trace the last minus word
1015 * printed.
1016 *
1017 * For '--graph' to work with '--color-words', we need to output the graph prefix
1018 * on each line of color words output. Generally, there are two conditions on
1019 * which we should output the prefix.
1020 *
1021 *   1. diff_words->last_minus == 0 &&
1022 *      diff_words->current_plus == diff_words->plus.text.ptr
1023 *
1024 *      that is: the plus text must start as a new line, and if there is no minus
1025 *      word printed, a graph prefix must be printed.
1026 *
1027 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1028 *      *(diff_words->current_plus - 1) == '\n'
1029 *
1030 *      that is: a graph prefix must be printed following a '\n'
1031 */
1032static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1033{
1034        if ((diff_words->last_minus == 0 &&
1035                diff_words->current_plus == diff_words->plus.text.ptr) ||
1036                (diff_words->current_plus > diff_words->plus.text.ptr &&
1037                *(diff_words->current_plus - 1) == '\n')) {
1038                return 1;
1039        } else {
1040                return 0;
1041        }
1042}
1043
1044static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1045{
1046        struct diff_words_data *diff_words = priv;
1047        struct diff_words_style *style = diff_words->style;
1048        int minus_first, minus_len, plus_first, plus_len;
1049        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1050        struct diff_options *opt = diff_words->opt;
1051        const char *line_prefix;
1052
1053        if (line[0] != '@' || parse_hunk_header(line, len,
1054                        &minus_first, &minus_len, &plus_first, &plus_len))
1055                return;
1056
1057        assert(opt);
1058        line_prefix = diff_line_prefix(opt);
1059
1060        /* POSIX requires that first be decremented by one if len == 0... */
1061        if (minus_len) {
1062                minus_begin = diff_words->minus.orig[minus_first].begin;
1063                minus_end =
1064                        diff_words->minus.orig[minus_first + minus_len - 1].end;
1065        } else
1066                minus_begin = minus_end =
1067                        diff_words->minus.orig[minus_first].end;
1068
1069        if (plus_len) {
1070                plus_begin = diff_words->plus.orig[plus_first].begin;
1071                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1072        } else
1073                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1074
1075        if (color_words_output_graph_prefix(diff_words)) {
1076                fputs(line_prefix, diff_words->opt->file);
1077        }
1078        if (diff_words->current_plus != plus_begin) {
1079                fn_out_diff_words_write_helper(diff_words->opt->file,
1080                                &style->ctx, style->newline,
1081                                plus_begin - diff_words->current_plus,
1082                                diff_words->current_plus, line_prefix);
1083                if (*(plus_begin - 1) == '\n')
1084                        fputs(line_prefix, diff_words->opt->file);
1085        }
1086        if (minus_begin != minus_end) {
1087                fn_out_diff_words_write_helper(diff_words->opt->file,
1088                                &style->old, style->newline,
1089                                minus_end - minus_begin, minus_begin,
1090                                line_prefix);
1091        }
1092        if (plus_begin != plus_end) {
1093                fn_out_diff_words_write_helper(diff_words->opt->file,
1094                                &style->new, style->newline,
1095                                plus_end - plus_begin, plus_begin,
1096                                line_prefix);
1097        }
1098
1099        diff_words->current_plus = plus_end;
1100        diff_words->last_minus = minus_first;
1101}
1102
1103/* This function starts looking at *begin, and returns 0 iff a word was found. */
1104static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1105                int *begin, int *end)
1106{
1107        if (word_regex && *begin < buffer->size) {
1108                regmatch_t match[1];
1109                if (!regexec_buf(word_regex, buffer->ptr + *begin,
1110                                 buffer->size - *begin, 1, match, 0)) {
1111                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1112                                        '\n', match[0].rm_eo - match[0].rm_so);
1113                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1114                        *begin += match[0].rm_so;
1115                        return *begin >= *end;
1116                }
1117                return -1;
1118        }
1119
1120        /* find the next word */
1121        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1122                (*begin)++;
1123        if (*begin >= buffer->size)
1124                return -1;
1125
1126        /* find the end of the word */
1127        *end = *begin + 1;
1128        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1129                (*end)++;
1130
1131        return 0;
1132}
1133
1134/*
1135 * This function splits the words in buffer->text, stores the list with
1136 * newline separator into out, and saves the offsets of the original words
1137 * in buffer->orig.
1138 */
1139static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1140                regex_t *word_regex)
1141{
1142        int i, j;
1143        long alloc = 0;
1144
1145        out->size = 0;
1146        out->ptr = NULL;
1147
1148        /* fake an empty "0th" word */
1149        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1150        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1151        buffer->orig_nr = 1;
1152
1153        for (i = 0; i < buffer->text.size; i++) {
1154                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1155                        return;
1156
1157                /* store original boundaries */
1158                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1159                                buffer->orig_alloc);
1160                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1161                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1162                buffer->orig_nr++;
1163
1164                /* store one word */
1165                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1166                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1167                out->ptr[out->size + j - i] = '\n';
1168                out->size += j - i + 1;
1169
1170                i = j - 1;
1171        }
1172}
1173
1174/* this executes the word diff on the accumulated buffers */
1175static void diff_words_show(struct diff_words_data *diff_words)
1176{
1177        xpparam_t xpp;
1178        xdemitconf_t xecfg;
1179        mmfile_t minus, plus;
1180        struct diff_words_style *style = diff_words->style;
1181
1182        struct diff_options *opt = diff_words->opt;
1183        const char *line_prefix;
1184
1185        assert(opt);
1186        line_prefix = diff_line_prefix(opt);
1187
1188        /* special case: only removal */
1189        if (!diff_words->plus.text.size) {
1190                fputs(line_prefix, diff_words->opt->file);
1191                fn_out_diff_words_write_helper(diff_words->opt->file,
1192                        &style->old, style->newline,
1193                        diff_words->minus.text.size,
1194                        diff_words->minus.text.ptr, line_prefix);
1195                diff_words->minus.text.size = 0;
1196                return;
1197        }
1198
1199        diff_words->current_plus = diff_words->plus.text.ptr;
1200        diff_words->last_minus = 0;
1201
1202        memset(&xpp, 0, sizeof(xpp));
1203        memset(&xecfg, 0, sizeof(xecfg));
1204        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1205        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1206        xpp.flags = 0;
1207        /* as only the hunk header will be parsed, we need a 0-context */
1208        xecfg.ctxlen = 0;
1209        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1210                          &xpp, &xecfg))
1211                die("unable to generate word diff");
1212        free(minus.ptr);
1213        free(plus.ptr);
1214        if (diff_words->current_plus != diff_words->plus.text.ptr +
1215                        diff_words->plus.text.size) {
1216                if (color_words_output_graph_prefix(diff_words))
1217                        fputs(line_prefix, diff_words->opt->file);
1218                fn_out_diff_words_write_helper(diff_words->opt->file,
1219                        &style->ctx, style->newline,
1220                        diff_words->plus.text.ptr + diff_words->plus.text.size
1221                        - diff_words->current_plus, diff_words->current_plus,
1222                        line_prefix);
1223        }
1224        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1225}
1226
1227/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1228static void diff_words_flush(struct emit_callback *ecbdata)
1229{
1230        if (ecbdata->diff_words->minus.text.size ||
1231            ecbdata->diff_words->plus.text.size)
1232                diff_words_show(ecbdata->diff_words);
1233}
1234
1235static void diff_filespec_load_driver(struct diff_filespec *one)
1236{
1237        /* Use already-loaded driver */
1238        if (one->driver)
1239                return;
1240
1241        if (S_ISREG(one->mode))
1242                one->driver = userdiff_find_by_path(one->path);
1243
1244        /* Fallback to default settings */
1245        if (!one->driver)
1246                one->driver = userdiff_find_by_name("default");
1247}
1248
1249static const char *userdiff_word_regex(struct diff_filespec *one)
1250{
1251        diff_filespec_load_driver(one);
1252        return one->driver->word_regex;
1253}
1254
1255static void init_diff_words_data(struct emit_callback *ecbdata,
1256                                 struct diff_options *orig_opts,
1257                                 struct diff_filespec *one,
1258                                 struct diff_filespec *two)
1259{
1260        int i;
1261        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1262        memcpy(o, orig_opts, sizeof(struct diff_options));
1263
1264        ecbdata->diff_words =
1265                xcalloc(1, sizeof(struct diff_words_data));
1266        ecbdata->diff_words->type = o->word_diff;
1267        ecbdata->diff_words->opt = o;
1268        if (!o->word_regex)
1269                o->word_regex = userdiff_word_regex(one);
1270        if (!o->word_regex)
1271                o->word_regex = userdiff_word_regex(two);
1272        if (!o->word_regex)
1273                o->word_regex = diff_word_regex_cfg;
1274        if (o->word_regex) {
1275                ecbdata->diff_words->word_regex = (regex_t *)
1276                        xmalloc(sizeof(regex_t));
1277                if (regcomp(ecbdata->diff_words->word_regex,
1278                            o->word_regex,
1279                            REG_EXTENDED | REG_NEWLINE))
1280                        die ("Invalid regular expression: %s",
1281                             o->word_regex);
1282        }
1283        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1284                if (o->word_diff == diff_words_styles[i].type) {
1285                        ecbdata->diff_words->style =
1286                                &diff_words_styles[i];
1287                        break;
1288                }
1289        }
1290        if (want_color(o->use_color)) {
1291                struct diff_words_style *st = ecbdata->diff_words->style;
1292                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1293                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1294                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1295        }
1296}
1297
1298static void free_diff_words_data(struct emit_callback *ecbdata)
1299{
1300        if (ecbdata->diff_words) {
1301                diff_words_flush(ecbdata);
1302                free (ecbdata->diff_words->opt);
1303                free (ecbdata->diff_words->minus.text.ptr);
1304                free (ecbdata->diff_words->minus.orig);
1305                free (ecbdata->diff_words->plus.text.ptr);
1306                free (ecbdata->diff_words->plus.orig);
1307                if (ecbdata->diff_words->word_regex) {
1308                        regfree(ecbdata->diff_words->word_regex);
1309                        free(ecbdata->diff_words->word_regex);
1310                }
1311                FREE_AND_NULL(ecbdata->diff_words);
1312        }
1313}
1314
1315const char *diff_get_color(int diff_use_color, enum color_diff ix)
1316{
1317        if (want_color(diff_use_color))
1318                return diff_colors[ix];
1319        return "";
1320}
1321
1322const char *diff_line_prefix(struct diff_options *opt)
1323{
1324        struct strbuf *msgbuf;
1325        if (!opt->output_prefix)
1326                return "";
1327
1328        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1329        return msgbuf->buf;
1330}
1331
1332static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1333{
1334        const char *cp;
1335        unsigned long allot;
1336        size_t l = len;
1337
1338        if (ecb->truncate)
1339                return ecb->truncate(line, len);
1340        cp = line;
1341        allot = l;
1342        while (0 < l) {
1343                (void) utf8_width(&cp, &l);
1344                if (!cp)
1345                        break; /* truncated in the middle? */
1346        }
1347        return allot - l;
1348}
1349
1350static void find_lno(const char *line, struct emit_callback *ecbdata)
1351{
1352        const char *p;
1353        ecbdata->lno_in_preimage = 0;
1354        ecbdata->lno_in_postimage = 0;
1355        p = strchr(line, '-');
1356        if (!p)
1357                return; /* cannot happen */
1358        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1359        p = strchr(p, '+');
1360        if (!p)
1361                return; /* cannot happen */
1362        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1363}
1364
1365static void fn_out_consume(void *priv, char *line, unsigned long len)
1366{
1367        struct emit_callback *ecbdata = priv;
1368        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1369        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1370        struct diff_options *o = ecbdata->opt;
1371        const char *line_prefix = diff_line_prefix(o);
1372
1373        o->found_changes = 1;
1374
1375        if (ecbdata->header) {
1376                fprintf(o->file, "%s", ecbdata->header->buf);
1377                strbuf_reset(ecbdata->header);
1378                ecbdata->header = NULL;
1379        }
1380
1381        if (ecbdata->label_path[0]) {
1382                const char *name_a_tab, *name_b_tab;
1383
1384                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1385                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1386
1387                fprintf(o->file, "%s%s--- %s%s%s\n",
1388                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1389                fprintf(o->file, "%s%s+++ %s%s%s\n",
1390                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1391                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1392        }
1393
1394        if (diff_suppress_blank_empty
1395            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1396                line[0] = '\n';
1397                len = 1;
1398        }
1399
1400        if (line[0] == '@') {
1401                if (ecbdata->diff_words)
1402                        diff_words_flush(ecbdata);
1403                len = sane_truncate_line(ecbdata, line, len);
1404                find_lno(line, ecbdata);
1405                emit_hunk_header(ecbdata, line, len);
1406                return;
1407        }
1408
1409        if (ecbdata->diff_words) {
1410                enum diff_symbol s =
1411                        ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
1412                        DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
1413                if (line[0] == '-') {
1414                        diff_words_append(line, len,
1415                                          &ecbdata->diff_words->minus);
1416                        return;
1417                } else if (line[0] == '+') {
1418                        diff_words_append(line, len,
1419                                          &ecbdata->diff_words->plus);
1420                        return;
1421                } else if (starts_with(line, "\\ ")) {
1422                        /*
1423                         * Eat the "no newline at eof" marker as if we
1424                         * saw a "+" or "-" line with nothing on it,
1425                         * and return without diff_words_flush() to
1426                         * defer processing. If this is the end of
1427                         * preimage, more "+" lines may come after it.
1428                         */
1429                        return;
1430                }
1431                diff_words_flush(ecbdata);
1432                emit_diff_symbol(o, s, line, len, 0);
1433                return;
1434        }
1435
1436        switch (line[0]) {
1437        case '+':
1438                ecbdata->lno_in_postimage++;
1439                emit_add_line(reset, ecbdata, line + 1, len - 1);
1440                break;
1441        case '-':
1442                ecbdata->lno_in_preimage++;
1443                emit_del_line(reset, ecbdata, line + 1, len - 1);
1444                break;
1445        case ' ':
1446                ecbdata->lno_in_postimage++;
1447                ecbdata->lno_in_preimage++;
1448                emit_context_line(reset, ecbdata, line + 1, len - 1);
1449                break;
1450        default:
1451                /* incomplete line at the end */
1452                ecbdata->lno_in_preimage++;
1453                emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
1454                                 line, len, 0);
1455                break;
1456        }
1457}
1458
1459static char *pprint_rename(const char *a, const char *b)
1460{
1461        const char *old = a;
1462        const char *new = b;
1463        struct strbuf name = STRBUF_INIT;
1464        int pfx_length, sfx_length;
1465        int pfx_adjust_for_slash;
1466        int len_a = strlen(a);
1467        int len_b = strlen(b);
1468        int a_midlen, b_midlen;
1469        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1470        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1471
1472        if (qlen_a || qlen_b) {
1473                quote_c_style(a, &name, NULL, 0);
1474                strbuf_addstr(&name, " => ");
1475                quote_c_style(b, &name, NULL, 0);
1476                return strbuf_detach(&name, NULL);
1477        }
1478
1479        /* Find common prefix */
1480        pfx_length = 0;
1481        while (*old && *new && *old == *new) {
1482                if (*old == '/')
1483                        pfx_length = old - a + 1;
1484                old++;
1485                new++;
1486        }
1487
1488        /* Find common suffix */
1489        old = a + len_a;
1490        new = b + len_b;
1491        sfx_length = 0;
1492        /*
1493         * If there is a common prefix, it must end in a slash.  In
1494         * that case we let this loop run 1 into the prefix to see the
1495         * same slash.
1496         *
1497         * If there is no common prefix, we cannot do this as it would
1498         * underrun the input strings.
1499         */
1500        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1501        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1502               b + pfx_length - pfx_adjust_for_slash <= new &&
1503               *old == *new) {
1504                if (*old == '/')
1505                        sfx_length = len_a - (old - a);
1506                old--;
1507                new--;
1508        }
1509
1510        /*
1511         * pfx{mid-a => mid-b}sfx
1512         * {pfx-a => pfx-b}sfx
1513         * pfx{sfx-a => sfx-b}
1514         * name-a => name-b
1515         */
1516        a_midlen = len_a - pfx_length - sfx_length;
1517        b_midlen = len_b - pfx_length - sfx_length;
1518        if (a_midlen < 0)
1519                a_midlen = 0;
1520        if (b_midlen < 0)
1521                b_midlen = 0;
1522
1523        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1524        if (pfx_length + sfx_length) {
1525                strbuf_add(&name, a, pfx_length);
1526                strbuf_addch(&name, '{');
1527        }
1528        strbuf_add(&name, a + pfx_length, a_midlen);
1529        strbuf_addstr(&name, " => ");
1530        strbuf_add(&name, b + pfx_length, b_midlen);
1531        if (pfx_length + sfx_length) {
1532                strbuf_addch(&name, '}');
1533                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1534        }
1535        return strbuf_detach(&name, NULL);
1536}
1537
1538struct diffstat_t {
1539        int nr;
1540        int alloc;
1541        struct diffstat_file {
1542                char *from_name;
1543                char *name;
1544                char *print_name;
1545                unsigned is_unmerged:1;
1546                unsigned is_binary:1;
1547                unsigned is_renamed:1;
1548                unsigned is_interesting:1;
1549                uintmax_t added, deleted;
1550        } **files;
1551};
1552
1553static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1554                                          const char *name_a,
1555                                          const char *name_b)
1556{
1557        struct diffstat_file *x;
1558        x = xcalloc(1, sizeof(*x));
1559        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1560        diffstat->files[diffstat->nr++] = x;
1561        if (name_b) {
1562                x->from_name = xstrdup(name_a);
1563                x->name = xstrdup(name_b);
1564                x->is_renamed = 1;
1565        }
1566        else {
1567                x->from_name = NULL;
1568                x->name = xstrdup(name_a);
1569        }
1570        return x;
1571}
1572
1573static void diffstat_consume(void *priv, char *line, unsigned long len)
1574{
1575        struct diffstat_t *diffstat = priv;
1576        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1577
1578        if (line[0] == '+')
1579                x->added++;
1580        else if (line[0] == '-')
1581                x->deleted++;
1582}
1583
1584const char mime_boundary_leader[] = "------------";
1585
1586static int scale_linear(int it, int width, int max_change)
1587{
1588        if (!it)
1589                return 0;
1590        /*
1591         * make sure that at least one '-' or '+' is printed if
1592         * there is any change to this path. The easiest way is to
1593         * scale linearly as if the alloted width is one column shorter
1594         * than it is, and then add 1 to the result.
1595         */
1596        return 1 + (it * (width - 1) / max_change);
1597}
1598
1599static void show_name(FILE *file,
1600                      const char *prefix, const char *name, int len)
1601{
1602        fprintf(file, " %s%-*s |", prefix, len, name);
1603}
1604
1605static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1606{
1607        if (cnt <= 0)
1608                return;
1609        fprintf(file, "%s", set);
1610        while (cnt--)
1611                putc(ch, file);
1612        fprintf(file, "%s", reset);
1613}
1614
1615static void fill_print_name(struct diffstat_file *file)
1616{
1617        char *pname;
1618
1619        if (file->print_name)
1620                return;
1621
1622        if (!file->is_renamed) {
1623                struct strbuf buf = STRBUF_INIT;
1624                if (quote_c_style(file->name, &buf, NULL, 0)) {
1625                        pname = strbuf_detach(&buf, NULL);
1626                } else {
1627                        pname = file->name;
1628                        strbuf_release(&buf);
1629                }
1630        } else {
1631                pname = pprint_rename(file->from_name, file->name);
1632        }
1633        file->print_name = pname;
1634}
1635
1636int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1637{
1638        struct strbuf sb = STRBUF_INIT;
1639        int ret;
1640
1641        if (!files) {
1642                assert(insertions == 0 && deletions == 0);
1643                return fprintf(fp, "%s\n", " 0 files changed");
1644        }
1645
1646        strbuf_addf(&sb,
1647                    (files == 1) ? " %d file changed" : " %d files changed",
1648                    files);
1649
1650        /*
1651         * For binary diff, the caller may want to print "x files
1652         * changed" with insertions == 0 && deletions == 0.
1653         *
1654         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1655         * is probably less confusing (i.e skip over "2 files changed
1656         * but nothing about added/removed lines? Is this a bug in Git?").
1657         */
1658        if (insertions || deletions == 0) {
1659                strbuf_addf(&sb,
1660                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1661                            insertions);
1662        }
1663
1664        if (deletions || insertions == 0) {
1665                strbuf_addf(&sb,
1666                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1667                            deletions);
1668        }
1669        strbuf_addch(&sb, '\n');
1670        ret = fputs(sb.buf, fp);
1671        strbuf_release(&sb);
1672        return ret;
1673}
1674
1675static void show_stats(struct diffstat_t *data, struct diff_options *options)
1676{
1677        int i, len, add, del, adds = 0, dels = 0;
1678        uintmax_t max_change = 0, max_len = 0;
1679        int total_files = data->nr, count;
1680        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1681        const char *reset, *add_c, *del_c;
1682        const char *line_prefix = "";
1683        int extra_shown = 0;
1684
1685        if (data->nr == 0)
1686                return;
1687
1688        line_prefix = diff_line_prefix(options);
1689        count = options->stat_count ? options->stat_count : data->nr;
1690
1691        reset = diff_get_color_opt(options, DIFF_RESET);
1692        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1693        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1694
1695        /*
1696         * Find the longest filename and max number of changes
1697         */
1698        for (i = 0; (i < count) && (i < data->nr); i++) {
1699                struct diffstat_file *file = data->files[i];
1700                uintmax_t change = file->added + file->deleted;
1701
1702                if (!file->is_interesting && (change == 0)) {
1703                        count++; /* not shown == room for one more */
1704                        continue;
1705                }
1706                fill_print_name(file);
1707                len = strlen(file->print_name);
1708                if (max_len < len)
1709                        max_len = len;
1710
1711                if (file->is_unmerged) {
1712                        /* "Unmerged" is 8 characters */
1713                        bin_width = bin_width < 8 ? 8 : bin_width;
1714                        continue;
1715                }
1716                if (file->is_binary) {
1717                        /* "Bin XXX -> YYY bytes" */
1718                        int w = 14 + decimal_width(file->added)
1719                                + decimal_width(file->deleted);
1720                        bin_width = bin_width < w ? w : bin_width;
1721                        /* Display change counts aligned with "Bin" */
1722                        number_width = 3;
1723                        continue;
1724                }
1725
1726                if (max_change < change)
1727                        max_change = change;
1728        }
1729        count = i; /* where we can stop scanning in data->files[] */
1730
1731        /*
1732         * We have width = stat_width or term_columns() columns total.
1733         * We want a maximum of min(max_len, stat_name_width) for the name part.
1734         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1735         * We also need 1 for " " and 4 + decimal_width(max_change)
1736         * for " | NNNN " and one the empty column at the end, altogether
1737         * 6 + decimal_width(max_change).
1738         *
1739         * If there's not enough space, we will use the smaller of
1740         * stat_name_width (if set) and 5/8*width for the filename,
1741         * and the rest for constant elements + graph part, but no more
1742         * than stat_graph_width for the graph part.
1743         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1744         * for the standard terminal size).
1745         *
1746         * In other words: stat_width limits the maximum width, and
1747         * stat_name_width fixes the maximum width of the filename,
1748         * and is also used to divide available columns if there
1749         * aren't enough.
1750         *
1751         * Binary files are displayed with "Bin XXX -> YYY bytes"
1752         * instead of the change count and graph. This part is treated
1753         * similarly to the graph part, except that it is not
1754         * "scaled". If total width is too small to accommodate the
1755         * guaranteed minimum width of the filename part and the
1756         * separators and this message, this message will "overflow"
1757         * making the line longer than the maximum width.
1758         */
1759
1760        if (options->stat_width == -1)
1761                width = term_columns() - strlen(line_prefix);
1762        else
1763                width = options->stat_width ? options->stat_width : 80;
1764        number_width = decimal_width(max_change) > number_width ?
1765                decimal_width(max_change) : number_width;
1766
1767        if (options->stat_graph_width == -1)
1768                options->stat_graph_width = diff_stat_graph_width;
1769
1770        /*
1771         * Guarantee 3/8*16==6 for the graph part
1772         * and 5/8*16==10 for the filename part
1773         */
1774        if (width < 16 + 6 + number_width)
1775                width = 16 + 6 + number_width;
1776
1777        /*
1778         * First assign sizes that are wanted, ignoring available width.
1779         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1780         * starting from "XXX" should fit in graph_width.
1781         */
1782        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1783        if (options->stat_graph_width &&
1784            options->stat_graph_width < graph_width)
1785                graph_width = options->stat_graph_width;
1786
1787        name_width = (options->stat_name_width > 0 &&
1788                      options->stat_name_width < max_len) ?
1789                options->stat_name_width : max_len;
1790
1791        /*
1792         * Adjust adjustable widths not to exceed maximum width
1793         */
1794        if (name_width + number_width + 6 + graph_width > width) {
1795                if (graph_width > width * 3/8 - number_width - 6) {
1796                        graph_width = width * 3/8 - number_width - 6;
1797                        if (graph_width < 6)
1798                                graph_width = 6;
1799                }
1800
1801                if (options->stat_graph_width &&
1802                    graph_width > options->stat_graph_width)
1803                        graph_width = options->stat_graph_width;
1804                if (name_width > width - number_width - 6 - graph_width)
1805                        name_width = width - number_width - 6 - graph_width;
1806                else
1807                        graph_width = width - number_width - 6 - name_width;
1808        }
1809
1810        /*
1811         * From here name_width is the width of the name area,
1812         * and graph_width is the width of the graph area.
1813         * max_change is used to scale graph properly.
1814         */
1815        for (i = 0; i < count; i++) {
1816                const char *prefix = "";
1817                struct diffstat_file *file = data->files[i];
1818                char *name = file->print_name;
1819                uintmax_t added = file->added;
1820                uintmax_t deleted = file->deleted;
1821                int name_len;
1822
1823                if (!file->is_interesting && (added + deleted == 0))
1824                        continue;
1825
1826                /*
1827                 * "scale" the filename
1828                 */
1829                len = name_width;
1830                name_len = strlen(name);
1831                if (name_width < name_len) {
1832                        char *slash;
1833                        prefix = "...";
1834                        len -= 3;
1835                        name += name_len - len;
1836                        slash = strchr(name, '/');
1837                        if (slash)
1838                                name = slash;
1839                }
1840
1841                if (file->is_binary) {
1842                        fprintf(options->file, "%s", line_prefix);
1843                        show_name(options->file, prefix, name, len);
1844                        fprintf(options->file, " %*s", number_width, "Bin");
1845                        if (!added && !deleted) {
1846                                putc('\n', options->file);
1847                                continue;
1848                        }
1849                        fprintf(options->file, " %s%"PRIuMAX"%s",
1850                                del_c, deleted, reset);
1851                        fprintf(options->file, " -> ");
1852                        fprintf(options->file, "%s%"PRIuMAX"%s",
1853                                add_c, added, reset);
1854                        fprintf(options->file, " bytes");
1855                        fprintf(options->file, "\n");
1856                        continue;
1857                }
1858                else if (file->is_unmerged) {
1859                        fprintf(options->file, "%s", line_prefix);
1860                        show_name(options->file, prefix, name, len);
1861                        fprintf(options->file, " Unmerged\n");
1862                        continue;
1863                }
1864
1865                /*
1866                 * scale the add/delete
1867                 */
1868                add = added;
1869                del = deleted;
1870
1871                if (graph_width <= max_change) {
1872                        int total = scale_linear(add + del, graph_width, max_change);
1873                        if (total < 2 && add && del)
1874                                /* width >= 2 due to the sanity check */
1875                                total = 2;
1876                        if (add < del) {
1877                                add = scale_linear(add, graph_width, max_change);
1878                                del = total - add;
1879                        } else {
1880                                del = scale_linear(del, graph_width, max_change);
1881                                add = total - del;
1882                        }
1883                }
1884                fprintf(options->file, "%s", line_prefix);
1885                show_name(options->file, prefix, name, len);
1886                fprintf(options->file, " %*"PRIuMAX"%s",
1887                        number_width, added + deleted,
1888                        added + deleted ? " " : "");
1889                show_graph(options->file, '+', add, add_c, reset);
1890                show_graph(options->file, '-', del, del_c, reset);
1891                fprintf(options->file, "\n");
1892        }
1893
1894        for (i = 0; i < data->nr; i++) {
1895                struct diffstat_file *file = data->files[i];
1896                uintmax_t added = file->added;
1897                uintmax_t deleted = file->deleted;
1898
1899                if (file->is_unmerged ||
1900                    (!file->is_interesting && (added + deleted == 0))) {
1901                        total_files--;
1902                        continue;
1903                }
1904
1905                if (!file->is_binary) {
1906                        adds += added;
1907                        dels += deleted;
1908                }
1909                if (i < count)
1910                        continue;
1911                if (!extra_shown)
1912                        fprintf(options->file, "%s ...\n", line_prefix);
1913                extra_shown = 1;
1914        }
1915        fprintf(options->file, "%s", line_prefix);
1916        print_stat_summary(options->file, total_files, adds, dels);
1917}
1918
1919static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1920{
1921        int i, adds = 0, dels = 0, total_files = data->nr;
1922
1923        if (data->nr == 0)
1924                return;
1925
1926        for (i = 0; i < data->nr; i++) {
1927                int added = data->files[i]->added;
1928                int deleted= data->files[i]->deleted;
1929
1930                if (data->files[i]->is_unmerged ||
1931                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1932                        total_files--;
1933                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1934                        adds += added;
1935                        dels += deleted;
1936                }
1937        }
1938        fprintf(options->file, "%s", diff_line_prefix(options));
1939        print_stat_summary(options->file, total_files, adds, dels);
1940}
1941
1942static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1943{
1944        int i;
1945
1946        if (data->nr == 0)
1947                return;
1948
1949        for (i = 0; i < data->nr; i++) {
1950                struct diffstat_file *file = data->files[i];
1951
1952                fprintf(options->file, "%s", diff_line_prefix(options));
1953
1954                if (file->is_binary)
1955                        fprintf(options->file, "-\t-\t");
1956                else
1957                        fprintf(options->file,
1958                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1959                                file->added, file->deleted);
1960                if (options->line_termination) {
1961                        fill_print_name(file);
1962                        if (!file->is_renamed)
1963                                write_name_quoted(file->name, options->file,
1964                                                  options->line_termination);
1965                        else {
1966                                fputs(file->print_name, options->file);
1967                                putc(options->line_termination, options->file);
1968                        }
1969                } else {
1970                        if (file->is_renamed) {
1971                                putc('\0', options->file);
1972                                write_name_quoted(file->from_name, options->file, '\0');
1973                        }
1974                        write_name_quoted(file->name, options->file, '\0');
1975                }
1976        }
1977}
1978
1979struct dirstat_file {
1980        const char *name;
1981        unsigned long changed;
1982};
1983
1984struct dirstat_dir {
1985        struct dirstat_file *files;
1986        int alloc, nr, permille, cumulative;
1987};
1988
1989static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1990                unsigned long changed, const char *base, int baselen)
1991{
1992        unsigned long this_dir = 0;
1993        unsigned int sources = 0;
1994        const char *line_prefix = diff_line_prefix(opt);
1995
1996        while (dir->nr) {
1997                struct dirstat_file *f = dir->files;
1998                int namelen = strlen(f->name);
1999                unsigned long this;
2000                char *slash;
2001
2002                if (namelen < baselen)
2003                        break;
2004                if (memcmp(f->name, base, baselen))
2005                        break;
2006                slash = strchr(f->name + baselen, '/');
2007                if (slash) {
2008                        int newbaselen = slash + 1 - f->name;
2009                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2010                        sources++;
2011                } else {
2012                        this = f->changed;
2013                        dir->files++;
2014                        dir->nr--;
2015                        sources += 2;
2016                }
2017                this_dir += this;
2018        }
2019
2020        /*
2021         * We don't report dirstat's for
2022         *  - the top level
2023         *  - or cases where everything came from a single directory
2024         *    under this directory (sources == 1).
2025         */
2026        if (baselen && sources != 1) {
2027                if (this_dir) {
2028                        int permille = this_dir * 1000 / changed;
2029                        if (permille >= dir->permille) {
2030                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2031                                        permille / 10, permille % 10, baselen, base);
2032                                if (!dir->cumulative)
2033                                        return 0;
2034                        }
2035                }
2036        }
2037        return this_dir;
2038}
2039
2040static int dirstat_compare(const void *_a, const void *_b)
2041{
2042        const struct dirstat_file *a = _a;
2043        const struct dirstat_file *b = _b;
2044        return strcmp(a->name, b->name);
2045}
2046
2047static void show_dirstat(struct diff_options *options)
2048{
2049        int i;
2050        unsigned long changed;
2051        struct dirstat_dir dir;
2052        struct diff_queue_struct *q = &diff_queued_diff;
2053
2054        dir.files = NULL;
2055        dir.alloc = 0;
2056        dir.nr = 0;
2057        dir.permille = options->dirstat_permille;
2058        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2059
2060        changed = 0;
2061        for (i = 0; i < q->nr; i++) {
2062                struct diff_filepair *p = q->queue[i];
2063                const char *name;
2064                unsigned long copied, added, damage;
2065                int content_changed;
2066
2067                name = p->two->path ? p->two->path : p->one->path;
2068
2069                if (p->one->oid_valid && p->two->oid_valid)
2070                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
2071                else
2072                        content_changed = 1;
2073
2074                if (!content_changed) {
2075                        /*
2076                         * The SHA1 has not changed, so pre-/post-content is
2077                         * identical. We can therefore skip looking at the
2078                         * file contents altogether.
2079                         */
2080                        damage = 0;
2081                        goto found_damage;
2082                }
2083
2084                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2085                        /*
2086                         * In --dirstat-by-file mode, we don't really need to
2087                         * look at the actual file contents at all.
2088                         * The fact that the SHA1 changed is enough for us to
2089                         * add this file to the list of results
2090                         * (with each file contributing equal damage).
2091                         */
2092                        damage = 1;
2093                        goto found_damage;
2094                }
2095
2096                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2097                        diff_populate_filespec(p->one, 0);
2098                        diff_populate_filespec(p->two, 0);
2099                        diffcore_count_changes(p->one, p->two, NULL, NULL,
2100                                               &copied, &added);
2101                        diff_free_filespec_data(p->one);
2102                        diff_free_filespec_data(p->two);
2103                } else if (DIFF_FILE_VALID(p->one)) {
2104                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2105                        copied = added = 0;
2106                        diff_free_filespec_data(p->one);
2107                } else if (DIFF_FILE_VALID(p->two)) {
2108                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2109                        copied = 0;
2110                        added = p->two->size;
2111                        diff_free_filespec_data(p->two);
2112                } else
2113                        continue;
2114
2115                /*
2116                 * Original minus copied is the removed material,
2117                 * added is the new material.  They are both damages
2118                 * made to the preimage.
2119                 * If the resulting damage is zero, we know that
2120                 * diffcore_count_changes() considers the two entries to
2121                 * be identical, but since content_changed is true, we
2122                 * know that there must have been _some_ kind of change,
2123                 * so we force all entries to have damage > 0.
2124                 */
2125                damage = (p->one->size - copied) + added;
2126                if (!damage)
2127                        damage = 1;
2128
2129found_damage:
2130                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2131                dir.files[dir.nr].name = name;
2132                dir.files[dir.nr].changed = damage;
2133                changed += damage;
2134                dir.nr++;
2135        }
2136
2137        /* This can happen even with many files, if everything was renames */
2138        if (!changed)
2139                return;
2140
2141        /* Show all directories with more than x% of the changes */
2142        QSORT(dir.files, dir.nr, dirstat_compare);
2143        gather_dirstat(options, &dir, changed, "", 0);
2144}
2145
2146static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2147{
2148        int i;
2149        unsigned long changed;
2150        struct dirstat_dir dir;
2151
2152        if (data->nr == 0)
2153                return;
2154
2155        dir.files = NULL;
2156        dir.alloc = 0;
2157        dir.nr = 0;
2158        dir.permille = options->dirstat_permille;
2159        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2160
2161        changed = 0;
2162        for (i = 0; i < data->nr; i++) {
2163                struct diffstat_file *file = data->files[i];
2164                unsigned long damage = file->added + file->deleted;
2165                if (file->is_binary)
2166                        /*
2167                         * binary files counts bytes, not lines. Must find some
2168                         * way to normalize binary bytes vs. textual lines.
2169                         * The following heuristic assumes that there are 64
2170                         * bytes per "line".
2171                         * This is stupid and ugly, but very cheap...
2172                         */
2173                        damage = (damage + 63) / 64;
2174                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2175                dir.files[dir.nr].name = file->name;
2176                dir.files[dir.nr].changed = damage;
2177                changed += damage;
2178                dir.nr++;
2179        }
2180
2181        /* This can happen even with many files, if everything was renames */
2182        if (!changed)
2183                return;
2184
2185        /* Show all directories with more than x% of the changes */
2186        QSORT(dir.files, dir.nr, dirstat_compare);
2187        gather_dirstat(options, &dir, changed, "", 0);
2188}
2189
2190static void free_diffstat_info(struct diffstat_t *diffstat)
2191{
2192        int i;
2193        for (i = 0; i < diffstat->nr; i++) {
2194                struct diffstat_file *f = diffstat->files[i];
2195                if (f->name != f->print_name)
2196                        free(f->print_name);
2197                free(f->name);
2198                free(f->from_name);
2199                free(f);
2200        }
2201        free(diffstat->files);
2202}
2203
2204struct checkdiff_t {
2205        const char *filename;
2206        int lineno;
2207        int conflict_marker_size;
2208        struct diff_options *o;
2209        unsigned ws_rule;
2210        unsigned status;
2211};
2212
2213static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2214{
2215        char firstchar;
2216        int cnt;
2217
2218        if (len < marker_size + 1)
2219                return 0;
2220        firstchar = line[0];
2221        switch (firstchar) {
2222        case '=': case '>': case '<': case '|':
2223                break;
2224        default:
2225                return 0;
2226        }
2227        for (cnt = 1; cnt < marker_size; cnt++)
2228                if (line[cnt] != firstchar)
2229                        return 0;
2230        /* line[1] thru line[marker_size-1] are same as firstchar */
2231        if (len < marker_size + 1 || !isspace(line[marker_size]))
2232                return 0;
2233        return 1;
2234}
2235
2236static void checkdiff_consume(void *priv, char *line, unsigned long len)
2237{
2238        struct checkdiff_t *data = priv;
2239        int marker_size = data->conflict_marker_size;
2240        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2241        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2242        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2243        char *err;
2244        const char *line_prefix;
2245
2246        assert(data->o);
2247        line_prefix = diff_line_prefix(data->o);
2248
2249        if (line[0] == '+') {
2250                unsigned bad;
2251                data->lineno++;
2252                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2253                        data->status |= 1;
2254                        fprintf(data->o->file,
2255                                "%s%s:%d: leftover conflict marker\n",
2256                                line_prefix, data->filename, data->lineno);
2257                }
2258                bad = ws_check(line + 1, len - 1, data->ws_rule);
2259                if (!bad)
2260                        return;
2261                data->status |= bad;
2262                err = whitespace_error_string(bad);
2263                fprintf(data->o->file, "%s%s:%d: %s.\n",
2264                        line_prefix, data->filename, data->lineno, err);
2265                free(err);
2266                emit_line(data->o, set, reset, line, 1);
2267                ws_check_emit(line + 1, len - 1, data->ws_rule,
2268                              data->o->file, set, reset, ws);
2269        } else if (line[0] == ' ') {
2270                data->lineno++;
2271        } else if (line[0] == '@') {
2272                char *plus = strchr(line, '+');
2273                if (plus)
2274                        data->lineno = strtol(plus, NULL, 10) - 1;
2275                else
2276                        die("invalid diff");
2277        }
2278}
2279
2280static unsigned char *deflate_it(char *data,
2281                                 unsigned long size,
2282                                 unsigned long *result_size)
2283{
2284        int bound;
2285        unsigned char *deflated;
2286        git_zstream stream;
2287
2288        git_deflate_init(&stream, zlib_compression_level);
2289        bound = git_deflate_bound(&stream, size);
2290        deflated = xmalloc(bound);
2291        stream.next_out = deflated;
2292        stream.avail_out = bound;
2293
2294        stream.next_in = (unsigned char *)data;
2295        stream.avail_in = size;
2296        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2297                ; /* nothing */
2298        git_deflate_end(&stream);
2299        *result_size = stream.total_out;
2300        return deflated;
2301}
2302
2303static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2304                                  const char *prefix)
2305{
2306        void *cp;
2307        void *delta;
2308        void *deflated;
2309        void *data;
2310        unsigned long orig_size;
2311        unsigned long delta_size;
2312        unsigned long deflate_size;
2313        unsigned long data_size;
2314
2315        /* We could do deflated delta, or we could do just deflated two,
2316         * whichever is smaller.
2317         */
2318        delta = NULL;
2319        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2320        if (one->size && two->size) {
2321                delta = diff_delta(one->ptr, one->size,
2322                                   two->ptr, two->size,
2323                                   &delta_size, deflate_size);
2324                if (delta) {
2325                        void *to_free = delta;
2326                        orig_size = delta_size;
2327                        delta = deflate_it(delta, delta_size, &delta_size);
2328                        free(to_free);
2329                }
2330        }
2331
2332        if (delta && delta_size < deflate_size) {
2333                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2334                free(deflated);
2335                data = delta;
2336                data_size = delta_size;
2337        }
2338        else {
2339                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2340                free(delta);
2341                data = deflated;
2342                data_size = deflate_size;
2343        }
2344
2345        /* emit data encoded in base85 */
2346        cp = data;
2347        while (data_size) {
2348                int bytes = (52 < data_size) ? 52 : data_size;
2349                char line[70];
2350                data_size -= bytes;
2351                if (bytes <= 26)
2352                        line[0] = bytes + 'A' - 1;
2353                else
2354                        line[0] = bytes - 26 + 'a' - 1;
2355                encode_85(line + 1, cp, bytes);
2356                cp = (char *) cp + bytes;
2357                fprintf(file, "%s", prefix);
2358                fputs(line, file);
2359                fputc('\n', file);
2360        }
2361        fprintf(file, "%s\n", prefix);
2362        free(data);
2363}
2364
2365static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2366                             const char *prefix)
2367{
2368        fprintf(file, "%sGIT binary patch\n", prefix);
2369        emit_binary_diff_body(file, one, two, prefix);
2370        emit_binary_diff_body(file, two, one, prefix);
2371}
2372
2373int diff_filespec_is_binary(struct diff_filespec *one)
2374{
2375        if (one->is_binary == -1) {
2376                diff_filespec_load_driver(one);
2377                if (one->driver->binary != -1)
2378                        one->is_binary = one->driver->binary;
2379                else {
2380                        if (!one->data && DIFF_FILE_VALID(one))
2381                                diff_populate_filespec(one, CHECK_BINARY);
2382                        if (one->is_binary == -1 && one->data)
2383                                one->is_binary = buffer_is_binary(one->data,
2384                                                one->size);
2385                        if (one->is_binary == -1)
2386                                one->is_binary = 0;
2387                }
2388        }
2389        return one->is_binary;
2390}
2391
2392static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2393{
2394        diff_filespec_load_driver(one);
2395        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2396}
2397
2398void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2399{
2400        if (!options->a_prefix)
2401                options->a_prefix = a;
2402        if (!options->b_prefix)
2403                options->b_prefix = b;
2404}
2405
2406struct userdiff_driver *get_textconv(struct diff_filespec *one)
2407{
2408        if (!DIFF_FILE_VALID(one))
2409                return NULL;
2410
2411        diff_filespec_load_driver(one);
2412        return userdiff_get_textconv(one->driver);
2413}
2414
2415static void builtin_diff(const char *name_a,
2416                         const char *name_b,
2417                         struct diff_filespec *one,
2418                         struct diff_filespec *two,
2419                         const char *xfrm_msg,
2420                         int must_show_header,
2421                         struct diff_options *o,
2422                         int complete_rewrite)
2423{
2424        mmfile_t mf1, mf2;
2425        const char *lbl[2];
2426        char *a_one, *b_two;
2427        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2428        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2429        const char *a_prefix, *b_prefix;
2430        struct userdiff_driver *textconv_one = NULL;
2431        struct userdiff_driver *textconv_two = NULL;
2432        struct strbuf header = STRBUF_INIT;
2433        const char *line_prefix = diff_line_prefix(o);
2434
2435        diff_set_mnemonic_prefix(o, "a/", "b/");
2436        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2437                a_prefix = o->b_prefix;
2438                b_prefix = o->a_prefix;
2439        } else {
2440                a_prefix = o->a_prefix;
2441                b_prefix = o->b_prefix;
2442        }
2443
2444        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2445            (!one->mode || S_ISGITLINK(one->mode)) &&
2446            (!two->mode || S_ISGITLINK(two->mode))) {
2447                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2448                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2449                show_submodule_summary(o->file, one->path ? one->path : two->path,
2450                                line_prefix,
2451                                &one->oid, &two->oid,
2452                                two->dirty_submodule,
2453                                meta, del, add, reset);
2454                return;
2455        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2456                   (!one->mode || S_ISGITLINK(one->mode)) &&
2457                   (!two->mode || S_ISGITLINK(two->mode))) {
2458                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2459                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2460                show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2461                                line_prefix,
2462                                &one->oid, &two->oid,
2463                                two->dirty_submodule,
2464                                meta, del, add, reset, o);
2465                return;
2466        }
2467
2468        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2469                textconv_one = get_textconv(one);
2470                textconv_two = get_textconv(two);
2471        }
2472
2473        /* Never use a non-valid filename anywhere if at all possible */
2474        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2475        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2476
2477        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2478        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2479        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2480        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2481        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2482        if (lbl[0][0] == '/') {
2483                /* /dev/null */
2484                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2485                if (xfrm_msg)
2486                        strbuf_addstr(&header, xfrm_msg);
2487                must_show_header = 1;
2488        }
2489        else if (lbl[1][0] == '/') {
2490                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2491                if (xfrm_msg)
2492                        strbuf_addstr(&header, xfrm_msg);
2493                must_show_header = 1;
2494        }
2495        else {
2496                if (one->mode != two->mode) {
2497                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2498                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2499                        must_show_header = 1;
2500                }
2501                if (xfrm_msg)
2502                        strbuf_addstr(&header, xfrm_msg);
2503
2504                /*
2505                 * we do not run diff between different kind
2506                 * of objects.
2507                 */
2508                if ((one->mode ^ two->mode) & S_IFMT)
2509                        goto free_ab_and_return;
2510                if (complete_rewrite &&
2511                    (textconv_one || !diff_filespec_is_binary(one)) &&
2512                    (textconv_two || !diff_filespec_is_binary(two))) {
2513                        fprintf(o->file, "%s", header.buf);
2514                        strbuf_reset(&header);
2515                        emit_rewrite_diff(name_a, name_b, one, two,
2516                                                textconv_one, textconv_two, o);
2517                        o->found_changes = 1;
2518                        goto free_ab_and_return;
2519                }
2520        }
2521
2522        if (o->irreversible_delete && lbl[1][0] == '/') {
2523                fprintf(o->file, "%s", header.buf);
2524                strbuf_reset(&header);
2525                goto free_ab_and_return;
2526        } else if (!DIFF_OPT_TST(o, TEXT) &&
2527            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2528              (!textconv_two && diff_filespec_is_binary(two)) )) {
2529                if (!one->data && !two->data &&
2530                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2531                    !DIFF_OPT_TST(o, BINARY)) {
2532                        if (!oidcmp(&one->oid, &two->oid)) {
2533                                if (must_show_header)
2534                                        fprintf(o->file, "%s", header.buf);
2535                                goto free_ab_and_return;
2536                        }
2537                        fprintf(o->file, "%s", header.buf);
2538                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2539                                line_prefix, lbl[0], lbl[1]);
2540                        goto free_ab_and_return;
2541                }
2542                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2543                        die("unable to read files to diff");
2544                /* Quite common confusing case */
2545                if (mf1.size == mf2.size &&
2546                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2547                        if (must_show_header)
2548                                fprintf(o->file, "%s", header.buf);
2549                        goto free_ab_and_return;
2550                }
2551                fprintf(o->file, "%s", header.buf);
2552                strbuf_reset(&header);
2553                if (DIFF_OPT_TST(o, BINARY))
2554                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2555                else
2556                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2557                                line_prefix, lbl[0], lbl[1]);
2558                o->found_changes = 1;
2559        } else {
2560                /* Crazy xdl interfaces.. */
2561                const char *diffopts = getenv("GIT_DIFF_OPTS");
2562                const char *v;
2563                xpparam_t xpp;
2564                xdemitconf_t xecfg;
2565                struct emit_callback ecbdata;
2566                const struct userdiff_funcname *pe;
2567
2568                if (must_show_header) {
2569                        fprintf(o->file, "%s", header.buf);
2570                        strbuf_reset(&header);
2571                }
2572
2573                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2574                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2575
2576                pe = diff_funcname_pattern(one);
2577                if (!pe)
2578                        pe = diff_funcname_pattern(two);
2579
2580                memset(&xpp, 0, sizeof(xpp));
2581                memset(&xecfg, 0, sizeof(xecfg));
2582                memset(&ecbdata, 0, sizeof(ecbdata));
2583                ecbdata.label_path = lbl;
2584                ecbdata.color_diff = want_color(o->use_color);
2585                ecbdata.ws_rule = whitespace_rule(name_b);
2586                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2587                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2588                ecbdata.opt = o;
2589                ecbdata.header = header.len ? &header : NULL;
2590                xpp.flags = o->xdl_opts;
2591                xecfg.ctxlen = o->context;
2592                xecfg.interhunkctxlen = o->interhunkcontext;
2593                xecfg.flags = XDL_EMIT_FUNCNAMES;
2594                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2595                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2596                if (pe)
2597                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2598                if (!diffopts)
2599                        ;
2600                else if (skip_prefix(diffopts, "--unified=", &v))
2601                        xecfg.ctxlen = strtoul(v, NULL, 10);
2602                else if (skip_prefix(diffopts, "-u", &v))
2603                        xecfg.ctxlen = strtoul(v, NULL, 10);
2604                if (o->word_diff)
2605                        init_diff_words_data(&ecbdata, o, one, two);
2606                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2607                                  &xpp, &xecfg))
2608                        die("unable to generate diff for %s", one->path);
2609                if (o->word_diff)
2610                        free_diff_words_data(&ecbdata);
2611                if (textconv_one)
2612                        free(mf1.ptr);
2613                if (textconv_two)
2614                        free(mf2.ptr);
2615                xdiff_clear_find_func(&xecfg);
2616        }
2617
2618 free_ab_and_return:
2619        strbuf_release(&header);
2620        diff_free_filespec_data(one);
2621        diff_free_filespec_data(two);
2622        free(a_one);
2623        free(b_two);
2624        return;
2625}
2626
2627static void builtin_diffstat(const char *name_a, const char *name_b,
2628                             struct diff_filespec *one,
2629                             struct diff_filespec *two,
2630                             struct diffstat_t *diffstat,
2631                             struct diff_options *o,
2632                             struct diff_filepair *p)
2633{
2634        mmfile_t mf1, mf2;
2635        struct diffstat_file *data;
2636        int same_contents;
2637        int complete_rewrite = 0;
2638
2639        if (!DIFF_PAIR_UNMERGED(p)) {
2640                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2641                        complete_rewrite = 1;
2642        }
2643
2644        data = diffstat_add(diffstat, name_a, name_b);
2645        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2646
2647        if (!one || !two) {
2648                data->is_unmerged = 1;
2649                return;
2650        }
2651
2652        same_contents = !oidcmp(&one->oid, &two->oid);
2653
2654        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2655                data->is_binary = 1;
2656                if (same_contents) {
2657                        data->added = 0;
2658                        data->deleted = 0;
2659                } else {
2660                        data->added = diff_filespec_size(two);
2661                        data->deleted = diff_filespec_size(one);
2662                }
2663        }
2664
2665        else if (complete_rewrite) {
2666                diff_populate_filespec(one, 0);
2667                diff_populate_filespec(two, 0);
2668                data->deleted = count_lines(one->data, one->size);
2669                data->added = count_lines(two->data, two->size);
2670        }
2671
2672        else if (!same_contents) {
2673                /* Crazy xdl interfaces.. */
2674                xpparam_t xpp;
2675                xdemitconf_t xecfg;
2676
2677                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2678                        die("unable to read files to diff");
2679
2680                memset(&xpp, 0, sizeof(xpp));
2681                memset(&xecfg, 0, sizeof(xecfg));
2682                xpp.flags = o->xdl_opts;
2683                xecfg.ctxlen = o->context;
2684                xecfg.interhunkctxlen = o->interhunkcontext;
2685                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2686                                  &xpp, &xecfg))
2687                        die("unable to generate diffstat for %s", one->path);
2688        }
2689
2690        diff_free_filespec_data(one);
2691        diff_free_filespec_data(two);
2692}
2693
2694static void builtin_checkdiff(const char *name_a, const char *name_b,
2695                              const char *attr_path,
2696                              struct diff_filespec *one,
2697                              struct diff_filespec *two,
2698                              struct diff_options *o)
2699{
2700        mmfile_t mf1, mf2;
2701        struct checkdiff_t data;
2702
2703        if (!two)
2704                return;
2705
2706        memset(&data, 0, sizeof(data));
2707        data.filename = name_b ? name_b : name_a;
2708        data.lineno = 0;
2709        data.o = o;
2710        data.ws_rule = whitespace_rule(attr_path);
2711        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2712
2713        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2714                die("unable to read files to diff");
2715
2716        /*
2717         * All the other codepaths check both sides, but not checking
2718         * the "old" side here is deliberate.  We are checking the newly
2719         * introduced changes, and as long as the "new" side is text, we
2720         * can and should check what it introduces.
2721         */
2722        if (diff_filespec_is_binary(two))
2723                goto free_and_return;
2724        else {
2725                /* Crazy xdl interfaces.. */
2726                xpparam_t xpp;
2727                xdemitconf_t xecfg;
2728
2729                memset(&xpp, 0, sizeof(xpp));
2730                memset(&xecfg, 0, sizeof(xecfg));
2731                xecfg.ctxlen = 1; /* at least one context line */
2732                xpp.flags = 0;
2733                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2734                                  &xpp, &xecfg))
2735                        die("unable to generate checkdiff for %s", one->path);
2736
2737                if (data.ws_rule & WS_BLANK_AT_EOF) {
2738                        struct emit_callback ecbdata;
2739                        int blank_at_eof;
2740
2741                        ecbdata.ws_rule = data.ws_rule;
2742                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2743                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2744
2745                        if (blank_at_eof) {
2746                                static char *err;
2747                                if (!err)
2748                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2749                                fprintf(o->file, "%s:%d: %s.\n",
2750                                        data.filename, blank_at_eof, err);
2751                                data.status = 1; /* report errors */
2752                        }
2753                }
2754        }
2755 free_and_return:
2756        diff_free_filespec_data(one);
2757        diff_free_filespec_data(two);
2758        if (data.status)
2759                DIFF_OPT_SET(o, CHECK_FAILED);
2760}
2761
2762struct diff_filespec *alloc_filespec(const char *path)
2763{
2764        struct diff_filespec *spec;
2765
2766        FLEXPTR_ALLOC_STR(spec, path, path);
2767        spec->count = 1;
2768        spec->is_binary = -1;
2769        return spec;
2770}
2771
2772void free_filespec(struct diff_filespec *spec)
2773{
2774        if (!--spec->count) {
2775                diff_free_filespec_data(spec);
2776                free(spec);
2777        }
2778}
2779
2780void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
2781                   int oid_valid, unsigned short mode)
2782{
2783        if (mode) {
2784                spec->mode = canon_mode(mode);
2785                oidcpy(&spec->oid, oid);
2786                spec->oid_valid = oid_valid;
2787        }
2788}
2789
2790/*
2791 * Given a name and sha1 pair, if the index tells us the file in
2792 * the work tree has that object contents, return true, so that
2793 * prepare_temp_file() does not have to inflate and extract.
2794 */
2795static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
2796{
2797        const struct cache_entry *ce;
2798        struct stat st;
2799        int pos, len;
2800
2801        /*
2802         * We do not read the cache ourselves here, because the
2803         * benchmark with my previous version that always reads cache
2804         * shows that it makes things worse for diff-tree comparing
2805         * two linux-2.6 kernel trees in an already checked out work
2806         * tree.  This is because most diff-tree comparisons deal with
2807         * only a small number of files, while reading the cache is
2808         * expensive for a large project, and its cost outweighs the
2809         * savings we get by not inflating the object to a temporary
2810         * file.  Practically, this code only helps when we are used
2811         * by diff-cache --cached, which does read the cache before
2812         * calling us.
2813         */
2814        if (!active_cache)
2815                return 0;
2816
2817        /* We want to avoid the working directory if our caller
2818         * doesn't need the data in a normal file, this system
2819         * is rather slow with its stat/open/mmap/close syscalls,
2820         * and the object is contained in a pack file.  The pack
2821         * is probably already open and will be faster to obtain
2822         * the data through than the working directory.  Loose
2823         * objects however would tend to be slower as they need
2824         * to be individually opened and inflated.
2825         */
2826        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
2827                return 0;
2828
2829        /*
2830         * Similarly, if we'd have to convert the file contents anyway, that
2831         * makes the optimization not worthwhile.
2832         */
2833        if (!want_file && would_convert_to_git(&the_index, name))
2834                return 0;
2835
2836        len = strlen(name);
2837        pos = cache_name_pos(name, len);
2838        if (pos < 0)
2839                return 0;
2840        ce = active_cache[pos];
2841
2842        /*
2843         * This is not the sha1 we are looking for, or
2844         * unreusable because it is not a regular file.
2845         */
2846        if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
2847                return 0;
2848
2849        /*
2850         * If ce is marked as "assume unchanged", there is no
2851         * guarantee that work tree matches what we are looking for.
2852         */
2853        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2854                return 0;
2855
2856        /*
2857         * If ce matches the file in the work tree, we can reuse it.
2858         */
2859        if (ce_uptodate(ce) ||
2860            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2861                return 1;
2862
2863        return 0;
2864}
2865
2866static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2867{
2868        struct strbuf buf = STRBUF_INIT;
2869        char *dirty = "";
2870
2871        /* Are we looking at the work tree? */
2872        if (s->dirty_submodule)
2873                dirty = "-dirty";
2874
2875        strbuf_addf(&buf, "Subproject commit %s%s\n",
2876                    oid_to_hex(&s->oid), dirty);
2877        s->size = buf.len;
2878        if (size_only) {
2879                s->data = NULL;
2880                strbuf_release(&buf);
2881        } else {
2882                s->data = strbuf_detach(&buf, NULL);
2883                s->should_free = 1;
2884        }
2885        return 0;
2886}
2887
2888/*
2889 * While doing rename detection and pickaxe operation, we may need to
2890 * grab the data for the blob (or file) for our own in-core comparison.
2891 * diff_filespec has data and size fields for this purpose.
2892 */
2893int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2894{
2895        int size_only = flags & CHECK_SIZE_ONLY;
2896        int err = 0;
2897        /*
2898         * demote FAIL to WARN to allow inspecting the situation
2899         * instead of refusing.
2900         */
2901        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2902                                    ? SAFE_CRLF_WARN
2903                                    : safe_crlf);
2904
2905        if (!DIFF_FILE_VALID(s))
2906                die("internal error: asking to populate invalid file.");
2907        if (S_ISDIR(s->mode))
2908                return -1;
2909
2910        if (s->data)
2911                return 0;
2912
2913        if (size_only && 0 < s->size)
2914                return 0;
2915
2916        if (S_ISGITLINK(s->mode))
2917                return diff_populate_gitlink(s, size_only);
2918
2919        if (!s->oid_valid ||
2920            reuse_worktree_file(s->path, &s->oid, 0)) {
2921                struct strbuf buf = STRBUF_INIT;
2922                struct stat st;
2923                int fd;
2924
2925                if (lstat(s->path, &st) < 0) {
2926                        if (errno == ENOENT) {
2927                        err_empty:
2928                                err = -1;
2929                        empty:
2930                                s->data = (char *)"";
2931                                s->size = 0;
2932                                return err;
2933                        }
2934                }
2935                s->size = xsize_t(st.st_size);
2936                if (!s->size)
2937                        goto empty;
2938                if (S_ISLNK(st.st_mode)) {
2939                        struct strbuf sb = STRBUF_INIT;
2940
2941                        if (strbuf_readlink(&sb, s->path, s->size))
2942                                goto err_empty;
2943                        s->size = sb.len;
2944                        s->data = strbuf_detach(&sb, NULL);
2945                        s->should_free = 1;
2946                        return 0;
2947                }
2948
2949                /*
2950                 * Even if the caller would be happy with getting
2951                 * only the size, we cannot return early at this
2952                 * point if the path requires us to run the content
2953                 * conversion.
2954                 */
2955                if (size_only && !would_convert_to_git(&the_index, s->path))
2956                        return 0;
2957
2958                /*
2959                 * Note: this check uses xsize_t(st.st_size) that may
2960                 * not be the true size of the blob after it goes
2961                 * through convert_to_git().  This may not strictly be
2962                 * correct, but the whole point of big_file_threshold
2963                 * and is_binary check being that we want to avoid
2964                 * opening the file and inspecting the contents, this
2965                 * is probably fine.
2966                 */
2967                if ((flags & CHECK_BINARY) &&
2968                    s->size > big_file_threshold && s->is_binary == -1) {
2969                        s->is_binary = 1;
2970                        return 0;
2971                }
2972                fd = open(s->path, O_RDONLY);
2973                if (fd < 0)
2974                        goto err_empty;
2975                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2976                close(fd);
2977                s->should_munmap = 1;
2978
2979                /*
2980                 * Convert from working tree format to canonical git format
2981                 */
2982                if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
2983                        size_t size = 0;
2984                        munmap(s->data, s->size);
2985                        s->should_munmap = 0;
2986                        s->data = strbuf_detach(&buf, &size);
2987                        s->size = size;
2988                        s->should_free = 1;
2989                }
2990        }
2991        else {
2992                enum object_type type;
2993                if (size_only || (flags & CHECK_BINARY)) {
2994                        type = sha1_object_info(s->oid.hash, &s->size);
2995                        if (type < 0)
2996                                die("unable to read %s",
2997                                    oid_to_hex(&s->oid));
2998                        if (size_only)
2999                                return 0;
3000                        if (s->size > big_file_threshold && s->is_binary == -1) {
3001                                s->is_binary = 1;
3002                                return 0;
3003                        }
3004                }
3005                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3006                if (!s->data)
3007                        die("unable to read %s", oid_to_hex(&s->oid));
3008                s->should_free = 1;
3009        }
3010        return 0;
3011}
3012
3013void diff_free_filespec_blob(struct diff_filespec *s)
3014{
3015        if (s->should_free)
3016                free(s->data);
3017        else if (s->should_munmap)
3018                munmap(s->data, s->size);
3019
3020        if (s->should_free || s->should_munmap) {
3021                s->should_free = s->should_munmap = 0;
3022                s->data = NULL;
3023        }
3024}
3025
3026void diff_free_filespec_data(struct diff_filespec *s)
3027{
3028        diff_free_filespec_blob(s);
3029        FREE_AND_NULL(s->cnt_data);
3030}
3031
3032static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3033                           void *blob,
3034                           unsigned long size,
3035                           const struct object_id *oid,
3036                           int mode)
3037{
3038        int fd;
3039        struct strbuf buf = STRBUF_INIT;
3040        struct strbuf template = STRBUF_INIT;
3041        char *path_dup = xstrdup(path);
3042        const char *base = basename(path_dup);
3043
3044        /* Generate "XXXXXX_basename.ext" */
3045        strbuf_addstr(&template, "XXXXXX_");
3046        strbuf_addstr(&template, base);
3047
3048        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
3049        if (fd < 0)
3050                die_errno("unable to create temp-file");
3051        if (convert_to_working_tree(path,
3052                        (const char *)blob, (size_t)size, &buf)) {
3053                blob = buf.buf;
3054                size = buf.len;
3055        }
3056        if (write_in_full(fd, blob, size) != size)
3057                die_errno("unable to write temp-file");
3058        close_tempfile(&temp->tempfile);
3059        temp->name = get_tempfile_path(&temp->tempfile);
3060        oid_to_hex_r(temp->hex, oid);
3061        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3062        strbuf_release(&buf);
3063        strbuf_release(&template);
3064        free(path_dup);
3065}
3066
3067static struct diff_tempfile *prepare_temp_file(const char *name,
3068                struct diff_filespec *one)
3069{
3070        struct diff_tempfile *temp = claim_diff_tempfile();
3071
3072        if (!DIFF_FILE_VALID(one)) {
3073        not_a_valid_file:
3074                /* A '-' entry produces this for file-2, and
3075                 * a '+' entry produces this for file-1.
3076                 */
3077                temp->name = "/dev/null";
3078                xsnprintf(temp->hex, sizeof(temp->hex), ".");
3079                xsnprintf(temp->mode, sizeof(temp->mode), ".");
3080                return temp;
3081        }
3082
3083        if (!S_ISGITLINK(one->mode) &&
3084            (!one->oid_valid ||
3085             reuse_worktree_file(name, &one->oid, 1))) {
3086                struct stat st;
3087                if (lstat(name, &st) < 0) {
3088                        if (errno == ENOENT)
3089                                goto not_a_valid_file;
3090                        die_errno("stat(%s)", name);
3091                }
3092                if (S_ISLNK(st.st_mode)) {
3093                        struct strbuf sb = STRBUF_INIT;
3094                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
3095                                die_errno("readlink(%s)", name);
3096                        prep_temp_blob(name, temp, sb.buf, sb.len,
3097                                       (one->oid_valid ?
3098                                        &one->oid : &null_oid),
3099                                       (one->oid_valid ?
3100                                        one->mode : S_IFLNK));
3101                        strbuf_release(&sb);
3102                }
3103                else {
3104                        /* we can borrow from the file in the work tree */
3105                        temp->name = name;
3106                        if (!one->oid_valid)
3107                                oid_to_hex_r(temp->hex, &null_oid);
3108                        else
3109                                oid_to_hex_r(temp->hex, &one->oid);
3110                        /* Even though we may sometimes borrow the
3111                         * contents from the work tree, we always want
3112                         * one->mode.  mode is trustworthy even when
3113                         * !(one->oid_valid), as long as
3114                         * DIFF_FILE_VALID(one).
3115                         */
3116                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3117                }
3118                return temp;
3119        }
3120        else {
3121                if (diff_populate_filespec(one, 0))
3122                        die("cannot read data blob for %s", one->path);
3123                prep_temp_blob(name, temp, one->data, one->size,
3124                               &one->oid, one->mode);
3125        }
3126        return temp;
3127}
3128
3129static void add_external_diff_name(struct argv_array *argv,
3130                                   const char *name,
3131                                   struct diff_filespec *df)
3132{
3133        struct diff_tempfile *temp = prepare_temp_file(name, df);
3134        argv_array_push(argv, temp->name);
3135        argv_array_push(argv, temp->hex);
3136        argv_array_push(argv, temp->mode);
3137}
3138
3139/* An external diff command takes:
3140 *
3141 * diff-cmd name infile1 infile1-sha1 infile1-mode \
3142 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3143 *
3144 */
3145static void run_external_diff(const char *pgm,
3146                              const char *name,
3147                              const char *other,
3148                              struct diff_filespec *one,
3149                              struct diff_filespec *two,
3150                              const char *xfrm_msg,
3151                              int complete_rewrite,
3152                              struct diff_options *o)
3153{
3154        struct argv_array argv = ARGV_ARRAY_INIT;
3155        struct argv_array env = ARGV_ARRAY_INIT;
3156        struct diff_queue_struct *q = &diff_queued_diff;
3157
3158        argv_array_push(&argv, pgm);
3159        argv_array_push(&argv, name);
3160
3161        if (one && two) {
3162                add_external_diff_name(&argv, name, one);
3163                if (!other)
3164                        add_external_diff_name(&argv, name, two);
3165                else {
3166                        add_external_diff_name(&argv, other, two);
3167                        argv_array_push(&argv, other);
3168                        argv_array_push(&argv, xfrm_msg);
3169                }
3170        }
3171
3172        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3173        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3174
3175        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3176                die(_("external diff died, stopping at %s"), name);
3177
3178        remove_tempfile();
3179        argv_array_clear(&argv);
3180        argv_array_clear(&env);
3181}
3182
3183static int similarity_index(struct diff_filepair *p)
3184{
3185        return p->score * 100 / MAX_SCORE;
3186}
3187
3188static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3189{
3190        if (startup_info->have_repository)
3191                return find_unique_abbrev(oid->hash, abbrev);
3192        else {
3193                char *hex = oid_to_hex(oid);
3194                if (abbrev < 0)
3195                        abbrev = FALLBACK_DEFAULT_ABBREV;
3196                if (abbrev > GIT_SHA1_HEXSZ)
3197                        die("BUG: oid abbreviation out of range: %d", abbrev);
3198                if (abbrev)
3199                        hex[abbrev] = '\0';
3200                return hex;
3201        }
3202}
3203
3204static void fill_metainfo(struct strbuf *msg,
3205                          const char *name,
3206                          const char *other,
3207                          struct diff_filespec *one,
3208                          struct diff_filespec *two,
3209                          struct diff_options *o,
3210                          struct diff_filepair *p,
3211                          int *must_show_header,
3212                          int use_color)
3213{
3214        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3215        const char *reset = diff_get_color(use_color, DIFF_RESET);
3216        const char *line_prefix = diff_line_prefix(o);
3217
3218        *must_show_header = 1;
3219        strbuf_init(msg, PATH_MAX * 2 + 300);
3220        switch (p->status) {
3221        case DIFF_STATUS_COPIED:
3222                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3223                            line_prefix, set, similarity_index(p));
3224                strbuf_addf(msg, "%s\n%s%scopy from ",
3225                            reset,  line_prefix, set);
3226                quote_c_style(name, msg, NULL, 0);
3227                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3228                quote_c_style(other, msg, NULL, 0);
3229                strbuf_addf(msg, "%s\n", reset);
3230                break;
3231        case DIFF_STATUS_RENAMED:
3232                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3233                            line_prefix, set, similarity_index(p));
3234                strbuf_addf(msg, "%s\n%s%srename from ",
3235                            reset, line_prefix, set);
3236                quote_c_style(name, msg, NULL, 0);
3237                strbuf_addf(msg, "%s\n%s%srename to ",
3238                            reset, line_prefix, set);
3239                quote_c_style(other, msg, NULL, 0);
3240                strbuf_addf(msg, "%s\n", reset);
3241                break;
3242        case DIFF_STATUS_MODIFIED:
3243                if (p->score) {
3244                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3245                                    line_prefix,
3246                                    set, similarity_index(p), reset);
3247                        break;
3248                }
3249                /* fallthru */
3250        default:
3251                *must_show_header = 0;
3252        }
3253        if (one && two && oidcmp(&one->oid, &two->oid)) {
3254                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3255
3256                if (DIFF_OPT_TST(o, BINARY)) {
3257                        mmfile_t mf;
3258                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3259                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3260                                abbrev = 40;
3261                }
3262                strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3263                            diff_abbrev_oid(&one->oid, abbrev),
3264                            diff_abbrev_oid(&two->oid, abbrev));
3265                if (one->mode == two->mode)
3266                        strbuf_addf(msg, " %06o", one->mode);
3267                strbuf_addf(msg, "%s\n", reset);
3268        }
3269}
3270
3271static void run_diff_cmd(const char *pgm,
3272                         const char *name,
3273                         const char *other,
3274                         const char *attr_path,
3275                         struct diff_filespec *one,
3276                         struct diff_filespec *two,
3277                         struct strbuf *msg,
3278                         struct diff_options *o,
3279                         struct diff_filepair *p)
3280{
3281        const char *xfrm_msg = NULL;
3282        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3283        int must_show_header = 0;
3284
3285
3286        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3287                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3288                if (drv && drv->external)
3289                        pgm = drv->external;
3290        }
3291
3292        if (msg) {
3293                /*
3294                 * don't use colors when the header is intended for an
3295                 * external diff driver
3296                 */
3297                fill_metainfo(msg, name, other, one, two, o, p,
3298                              &must_show_header,
3299                              want_color(o->use_color) && !pgm);
3300                xfrm_msg = msg->len ? msg->buf : NULL;
3301        }
3302
3303        if (pgm) {
3304                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3305                                  complete_rewrite, o);
3306                return;
3307        }
3308        if (one && two)
3309                builtin_diff(name, other ? other : name,
3310                             one, two, xfrm_msg, must_show_header,
3311                             o, complete_rewrite);
3312        else
3313                fprintf(o->file, "* Unmerged path %s\n", name);
3314}
3315
3316static void diff_fill_oid_info(struct diff_filespec *one)
3317{
3318        if (DIFF_FILE_VALID(one)) {
3319                if (!one->oid_valid) {
3320                        struct stat st;
3321                        if (one->is_stdin) {
3322                                oidclr(&one->oid);
3323                                return;
3324                        }
3325                        if (lstat(one->path, &st) < 0)
3326                                die_errno("stat '%s'", one->path);
3327                        if (index_path(one->oid.hash, one->path, &st, 0))
3328                                die("cannot hash %s", one->path);
3329                }
3330        }
3331        else
3332                oidclr(&one->oid);
3333}
3334
3335static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3336{
3337        /* Strip the prefix but do not molest /dev/null and absolute paths */
3338        if (*namep && **namep != '/') {
3339                *namep += prefix_length;
3340                if (**namep == '/')
3341                        ++*namep;
3342        }
3343        if (*otherp && **otherp != '/') {
3344                *otherp += prefix_length;
3345                if (**otherp == '/')
3346                        ++*otherp;
3347        }
3348}
3349
3350static void run_diff(struct diff_filepair *p, struct diff_options *o)
3351{
3352        const char *pgm = external_diff();
3353        struct strbuf msg;
3354        struct diff_filespec *one = p->one;
3355        struct diff_filespec *two = p->two;
3356        const char *name;
3357        const char *other;
3358        const char *attr_path;
3359
3360        name  = one->path;
3361        other = (strcmp(name, two->path) ? two->path : NULL);
3362        attr_path = name;
3363        if (o->prefix_length)
3364                strip_prefix(o->prefix_length, &name, &other);
3365
3366        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3367                pgm = NULL;
3368
3369        if (DIFF_PAIR_UNMERGED(p)) {
3370                run_diff_cmd(pgm, name, NULL, attr_path,
3371                             NULL, NULL, NULL, o, p);
3372                return;
3373        }
3374
3375        diff_fill_oid_info(one);
3376        diff_fill_oid_info(two);
3377
3378        if (!pgm &&
3379            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3380            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3381                /*
3382                 * a filepair that changes between file and symlink
3383                 * needs to be split into deletion and creation.
3384                 */
3385                struct diff_filespec *null = alloc_filespec(two->path);
3386                run_diff_cmd(NULL, name, other, attr_path,
3387                             one, null, &msg, o, p);
3388                free(null);
3389                strbuf_release(&msg);
3390
3391                null = alloc_filespec(one->path);
3392                run_diff_cmd(NULL, name, other, attr_path,
3393                             null, two, &msg, o, p);
3394                free(null);
3395        }
3396        else
3397                run_diff_cmd(pgm, name, other, attr_path,
3398                             one, two, &msg, o, p);
3399
3400        strbuf_release(&msg);
3401}
3402
3403static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3404                         struct diffstat_t *diffstat)
3405{
3406        const char *name;
3407        const char *other;
3408
3409        if (DIFF_PAIR_UNMERGED(p)) {
3410                /* unmerged */
3411                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3412                return;
3413        }
3414
3415        name = p->one->path;
3416        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3417
3418        if (o->prefix_length)
3419                strip_prefix(o->prefix_length, &name, &other);
3420
3421        diff_fill_oid_info(p->one);
3422        diff_fill_oid_info(p->two);
3423
3424        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3425}
3426
3427static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3428{
3429        const char *name;
3430        const char *other;
3431        const char *attr_path;
3432
3433        if (DIFF_PAIR_UNMERGED(p)) {
3434                /* unmerged */
3435                return;
3436        }
3437
3438        name = p->one->path;
3439        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3440        attr_path = other ? other : name;
3441
3442        if (o->prefix_length)
3443                strip_prefix(o->prefix_length, &name, &other);
3444
3445        diff_fill_oid_info(p->one);
3446        diff_fill_oid_info(p->two);
3447
3448        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3449}
3450
3451void diff_setup(struct diff_options *options)
3452{
3453        memcpy(options, &default_diff_options, sizeof(*options));
3454
3455        options->file = stdout;
3456
3457        options->abbrev = DEFAULT_ABBREV;
3458        options->line_termination = '\n';
3459        options->break_opt = -1;
3460        options->rename_limit = -1;
3461        options->dirstat_permille = diff_dirstat_permille_default;
3462        options->context = diff_context_default;
3463        options->interhunkcontext = diff_interhunk_context_default;
3464        options->ws_error_highlight = ws_error_highlight_default;
3465        DIFF_OPT_SET(options, RENAME_EMPTY);
3466
3467        /* pathchange left =NULL by default */
3468        options->change = diff_change;
3469        options->add_remove = diff_addremove;
3470        options->use_color = diff_use_color_default;
3471        options->detect_rename = diff_detect_rename_default;
3472        options->xdl_opts |= diff_algorithm;
3473        if (diff_indent_heuristic)
3474                DIFF_XDL_SET(options, INDENT_HEURISTIC);
3475
3476        options->orderfile = diff_order_file_cfg;
3477
3478        if (diff_no_prefix) {
3479                options->a_prefix = options->b_prefix = "";
3480        } else if (!diff_mnemonic_prefix) {
3481                options->a_prefix = "a/";
3482                options->b_prefix = "b/";
3483        }
3484}
3485
3486void diff_setup_done(struct diff_options *options)
3487{
3488        int count = 0;
3489
3490        if (options->set_default)
3491                options->set_default(options);
3492
3493        if (options->output_format & DIFF_FORMAT_NAME)
3494                count++;
3495        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3496                count++;
3497        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3498                count++;
3499        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3500                count++;
3501        if (count > 1)
3502                die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3503
3504        /*
3505         * Most of the time we can say "there are changes"
3506         * only by checking if there are changed paths, but
3507         * --ignore-whitespace* options force us to look
3508         * inside contents.
3509         */
3510
3511        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3512            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3513            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3514                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3515        else
3516                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3517
3518        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3519                options->detect_rename = DIFF_DETECT_COPY;
3520
3521        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3522                options->prefix = NULL;
3523        if (options->prefix)
3524                options->prefix_length = strlen(options->prefix);
3525        else
3526                options->prefix_length = 0;
3527
3528        if (options->output_format & (DIFF_FORMAT_NAME |
3529                                      DIFF_FORMAT_NAME_STATUS |
3530                                      DIFF_FORMAT_CHECKDIFF |
3531                                      DIFF_FORMAT_NO_OUTPUT))
3532                options->output_format &= ~(DIFF_FORMAT_RAW |
3533                                            DIFF_FORMAT_NUMSTAT |
3534                                            DIFF_FORMAT_DIFFSTAT |
3535                                            DIFF_FORMAT_SHORTSTAT |
3536                                            DIFF_FORMAT_DIRSTAT |
3537                                            DIFF_FORMAT_SUMMARY |
3538                                            DIFF_FORMAT_PATCH);
3539
3540        /*
3541         * These cases always need recursive; we do not drop caller-supplied
3542         * recursive bits for other formats here.
3543         */
3544        if (options->output_format & (DIFF_FORMAT_PATCH |
3545                                      DIFF_FORMAT_NUMSTAT |
3546                                      DIFF_FORMAT_DIFFSTAT |
3547                                      DIFF_FORMAT_SHORTSTAT |
3548                                      DIFF_FORMAT_DIRSTAT |
3549                                      DIFF_FORMAT_SUMMARY |
3550                                      DIFF_FORMAT_CHECKDIFF))
3551                DIFF_OPT_SET(options, RECURSIVE);
3552        /*
3553         * Also pickaxe would not work very well if you do not say recursive
3554         */
3555        if (options->pickaxe)
3556                DIFF_OPT_SET(options, RECURSIVE);
3557        /*
3558         * When patches are generated, submodules diffed against the work tree
3559         * must be checked for dirtiness too so it can be shown in the output
3560         */
3561        if (options->output_format & DIFF_FORMAT_PATCH)
3562                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3563
3564        if (options->detect_rename && options->rename_limit < 0)
3565                options->rename_limit = diff_rename_limit_default;
3566        if (options->setup & DIFF_SETUP_USE_CACHE) {
3567                if (!active_cache)
3568                        /* read-cache does not die even when it fails
3569                         * so it is safe for us to do this here.  Also
3570                         * it does not smudge active_cache or active_nr
3571                         * when it fails, so we do not have to worry about
3572                         * cleaning it up ourselves either.
3573                         */
3574                        read_cache();
3575        }
3576        if (40 < options->abbrev)
3577                options->abbrev = 40; /* full */
3578
3579        /*
3580         * It does not make sense to show the first hit we happened
3581         * to have found.  It does not make sense not to return with
3582         * exit code in such a case either.
3583         */
3584        if (DIFF_OPT_TST(options, QUICK)) {
3585                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3586                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3587        }
3588
3589        options->diff_path_counter = 0;
3590
3591        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3592                die(_("--follow requires exactly one pathspec"));
3593}
3594
3595static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3596{
3597        char c, *eq;
3598        int len;
3599
3600        if (*arg != '-')
3601                return 0;
3602        c = *++arg;
3603        if (!c)
3604                return 0;
3605        if (c == arg_short) {
3606                c = *++arg;
3607                if (!c)
3608                        return 1;
3609                if (val && isdigit(c)) {
3610                        char *end;
3611                        int n = strtoul(arg, &end, 10);
3612                        if (*end)
3613                                return 0;
3614                        *val = n;
3615                        return 1;
3616                }
3617                return 0;
3618        }
3619        if (c != '-')
3620                return 0;
3621        arg++;
3622        eq = strchrnul(arg, '=');
3623        len = eq - arg;
3624        if (!len || strncmp(arg, arg_long, len))
3625                return 0;
3626        if (*eq) {
3627                int n;
3628                char *end;
3629                if (!isdigit(*++eq))
3630                        return 0;
3631                n = strtoul(eq, &end, 10);
3632                if (*end)
3633                        return 0;
3634                *val = n;
3635        }
3636        return 1;
3637}
3638
3639static int diff_scoreopt_parse(const char *opt);
3640
3641static inline int short_opt(char opt, const char **argv,
3642                            const char **optarg)
3643{
3644        const char *arg = argv[0];
3645        if (arg[0] != '-' || arg[1] != opt)
3646                return 0;
3647        if (arg[2] != '\0') {
3648                *optarg = arg + 2;
3649                return 1;
3650        }
3651        if (!argv[1])
3652                die("Option '%c' requires a value", opt);
3653        *optarg = argv[1];
3654        return 2;
3655}
3656
3657int parse_long_opt(const char *opt, const char **argv,
3658                   const char **optarg)
3659{
3660        const char *arg = argv[0];
3661        if (!skip_prefix(arg, "--", &arg))
3662                return 0;
3663        if (!skip_prefix(arg, opt, &arg))
3664                return 0;
3665        if (*arg == '=') { /* stuck form: --option=value */
3666                *optarg = arg + 1;
3667                return 1;
3668        }
3669        if (*arg != '\0')
3670                return 0;
3671        /* separate form: --option value */
3672        if (!argv[1])
3673                die("Option '--%s' requires a value", opt);
3674        *optarg = argv[1];
3675        return 2;
3676}
3677
3678static int stat_opt(struct diff_options *options, const char **av)
3679{
3680        const char *arg = av[0];
3681        char *end;
3682        int width = options->stat_width;
3683        int name_width = options->stat_name_width;
3684        int graph_width = options->stat_graph_width;
3685        int count = options->stat_count;
3686        int argcount = 1;
3687
3688        if (!skip_prefix(arg, "--stat", &arg))
3689                die("BUG: stat option does not begin with --stat: %s", arg);
3690        end = (char *)arg;
3691
3692        switch (*arg) {
3693        case '-':
3694                if (skip_prefix(arg, "-width", &arg)) {
3695                        if (*arg == '=')
3696                                width = strtoul(arg + 1, &end, 10);
3697                        else if (!*arg && !av[1])
3698                                die_want_option("--stat-width");
3699                        else if (!*arg) {
3700                                width = strtoul(av[1], &end, 10);
3701                                argcount = 2;
3702                        }
3703                } else if (skip_prefix(arg, "-name-width", &arg)) {
3704                        if (*arg == '=')
3705                                name_width = strtoul(arg + 1, &end, 10);
3706                        else if (!*arg && !av[1])
3707                                die_want_option("--stat-name-width");
3708                        else if (!*arg) {
3709                                name_width = strtoul(av[1], &end, 10);
3710                                argcount = 2;
3711                        }
3712                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3713                        if (*arg == '=')
3714                                graph_width = strtoul(arg + 1, &end, 10);
3715                        else if (!*arg && !av[1])
3716                                die_want_option("--stat-graph-width");
3717                        else if (!*arg) {
3718                                graph_width = strtoul(av[1], &end, 10);
3719                                argcount = 2;
3720                        }
3721                } else if (skip_prefix(arg, "-count", &arg)) {
3722                        if (*arg == '=')
3723                                count = strtoul(arg + 1, &end, 10);
3724                        else if (!*arg && !av[1])
3725                                die_want_option("--stat-count");
3726                        else if (!*arg) {
3727                                count = strtoul(av[1], &end, 10);
3728                                argcount = 2;
3729                        }
3730                }
3731                break;
3732        case '=':
3733                width = strtoul(arg+1, &end, 10);
3734                if (*end == ',')
3735                        name_width = strtoul(end+1, &end, 10);
3736                if (*end == ',')
3737                        count = strtoul(end+1, &end, 10);
3738        }
3739
3740        /* Important! This checks all the error cases! */
3741        if (*end)
3742                return 0;
3743        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3744        options->stat_name_width = name_width;
3745        options->stat_graph_width = graph_width;
3746        options->stat_width = width;
3747        options->stat_count = count;
3748        return argcount;
3749}
3750
3751static int parse_dirstat_opt(struct diff_options *options, const char *params)
3752{
3753        struct strbuf errmsg = STRBUF_INIT;
3754        if (parse_dirstat_params(options, params, &errmsg))
3755                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3756                    errmsg.buf);
3757        strbuf_release(&errmsg);
3758        /*
3759         * The caller knows a dirstat-related option is given from the command
3760         * line; allow it to say "return this_function();"
3761         */
3762        options->output_format |= DIFF_FORMAT_DIRSTAT;
3763        return 1;
3764}
3765
3766static int parse_submodule_opt(struct diff_options *options, const char *value)
3767{
3768        if (parse_submodule_params(options, value))
3769                die(_("Failed to parse --submodule option parameter: '%s'"),
3770                        value);
3771        return 1;
3772}
3773
3774static const char diff_status_letters[] = {
3775        DIFF_STATUS_ADDED,
3776        DIFF_STATUS_COPIED,
3777        DIFF_STATUS_DELETED,
3778        DIFF_STATUS_MODIFIED,
3779        DIFF_STATUS_RENAMED,
3780        DIFF_STATUS_TYPE_CHANGED,
3781        DIFF_STATUS_UNKNOWN,
3782        DIFF_STATUS_UNMERGED,
3783        DIFF_STATUS_FILTER_AON,
3784        DIFF_STATUS_FILTER_BROKEN,
3785        '\0',
3786};
3787
3788static unsigned int filter_bit['Z' + 1];
3789
3790static void prepare_filter_bits(void)
3791{
3792        int i;
3793
3794        if (!filter_bit[DIFF_STATUS_ADDED]) {
3795                for (i = 0; diff_status_letters[i]; i++)
3796                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3797        }
3798}
3799
3800static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3801{
3802        return opt->filter & filter_bit[(int) status];
3803}
3804
3805static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3806{
3807        int i, optch;
3808
3809        prepare_filter_bits();
3810
3811        /*
3812         * If there is a negation e.g. 'd' in the input, and we haven't
3813         * initialized the filter field with another --diff-filter, start
3814         * from full set of bits, except for AON.
3815         */
3816        if (!opt->filter) {
3817                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3818                        if (optch < 'a' || 'z' < optch)
3819                                continue;
3820                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3821                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3822                        break;
3823                }
3824        }
3825
3826        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3827                unsigned int bit;
3828                int negate;
3829
3830                if ('a' <= optch && optch <= 'z') {
3831                        negate = 1;
3832                        optch = toupper(optch);
3833                } else {
3834                        negate = 0;
3835                }
3836
3837                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3838                if (!bit)
3839                        return optarg[i];
3840                if (negate)
3841                        opt->filter &= ~bit;
3842                else
3843                        opt->filter |= bit;
3844        }
3845        return 0;
3846}
3847
3848static void enable_patch_output(int *fmt) {
3849        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3850        *fmt |= DIFF_FORMAT_PATCH;
3851}
3852
3853static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3854{
3855        int val = parse_ws_error_highlight(arg);
3856
3857        if (val < 0) {
3858                error("unknown value after ws-error-highlight=%.*s",
3859                      -1 - val, arg);
3860                return 0;
3861        }
3862        opt->ws_error_highlight = val;
3863        return 1;
3864}
3865
3866int diff_opt_parse(struct diff_options *options,
3867                   const char **av, int ac, const char *prefix)
3868{
3869        const char *arg = av[0];
3870        const char *optarg;
3871        int argcount;
3872
3873        if (!prefix)
3874                prefix = "";
3875
3876        /* Output format options */
3877        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3878            || opt_arg(arg, 'U', "unified", &options->context))
3879                enable_patch_output(&options->output_format);
3880        else if (!strcmp(arg, "--raw"))
3881                options->output_format |= DIFF_FORMAT_RAW;
3882        else if (!strcmp(arg, "--patch-with-raw")) {
3883                enable_patch_output(&options->output_format);
3884                options->output_format |= DIFF_FORMAT_RAW;
3885        } else if (!strcmp(arg, "--numstat"))
3886                options->output_format |= DIFF_FORMAT_NUMSTAT;
3887        else if (!strcmp(arg, "--shortstat"))
3888                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3889        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3890                return parse_dirstat_opt(options, "");
3891        else if (skip_prefix(arg, "-X", &arg))
3892                return parse_dirstat_opt(options, arg);
3893        else if (skip_prefix(arg, "--dirstat=", &arg))
3894                return parse_dirstat_opt(options, arg);
3895        else if (!strcmp(arg, "--cumulative"))
3896                return parse_dirstat_opt(options, "cumulative");
3897        else if (!strcmp(arg, "--dirstat-by-file"))
3898                return parse_dirstat_opt(options, "files");
3899        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3900                parse_dirstat_opt(options, "files");
3901                return parse_dirstat_opt(options, arg);
3902        }
3903        else if (!strcmp(arg, "--check"))
3904                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3905        else if (!strcmp(arg, "--summary"))
3906                options->output_format |= DIFF_FORMAT_SUMMARY;
3907        else if (!strcmp(arg, "--patch-with-stat")) {
3908                enable_patch_output(&options->output_format);
3909                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3910        } else if (!strcmp(arg, "--name-only"))
3911                options->output_format |= DIFF_FORMAT_NAME;
3912        else if (!strcmp(arg, "--name-status"))
3913                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3914        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3915                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3916        else if (starts_with(arg, "--stat"))
3917                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3918                return stat_opt(options, av);
3919
3920        /* renames options */
3921        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3922                 !strcmp(arg, "--break-rewrites")) {
3923                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3924                        return error("invalid argument to -B: %s", arg+2);
3925        }
3926        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3927                 !strcmp(arg, "--find-renames")) {
3928                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3929                        return error("invalid argument to -M: %s", arg+2);
3930                options->detect_rename = DIFF_DETECT_RENAME;
3931        }
3932        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3933                options->irreversible_delete = 1;
3934        }
3935        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3936                 !strcmp(arg, "--find-copies")) {
3937                if (options->detect_rename == DIFF_DETECT_COPY)
3938                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3939                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3940                        return error("invalid argument to -C: %s", arg+2);
3941                options->detect_rename = DIFF_DETECT_COPY;
3942        }
3943        else if (!strcmp(arg, "--no-renames"))
3944                options->detect_rename = 0;
3945        else if (!strcmp(arg, "--rename-empty"))
3946                DIFF_OPT_SET(options, RENAME_EMPTY);
3947        else if (!strcmp(arg, "--no-rename-empty"))
3948                DIFF_OPT_CLR(options, RENAME_EMPTY);
3949        else if (!strcmp(arg, "--relative"))
3950                DIFF_OPT_SET(options, RELATIVE_NAME);
3951        else if (skip_prefix(arg, "--relative=", &arg)) {
3952                DIFF_OPT_SET(options, RELATIVE_NAME);
3953                options->prefix = arg;
3954        }
3955
3956        /* xdiff options */
3957        else if (!strcmp(arg, "--minimal"))
3958                DIFF_XDL_SET(options, NEED_MINIMAL);
3959        else if (!strcmp(arg, "--no-minimal"))
3960                DIFF_XDL_CLR(options, NEED_MINIMAL);
3961        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3962                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3963        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3964                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3965        else if (!strcmp(arg, "--ignore-space-at-eol"))
3966                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3967        else if (!strcmp(arg, "--ignore-blank-lines"))
3968                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3969        else if (!strcmp(arg, "--indent-heuristic"))
3970                DIFF_XDL_SET(options, INDENT_HEURISTIC);
3971        else if (!strcmp(arg, "--no-indent-heuristic"))
3972                DIFF_XDL_CLR(options, INDENT_HEURISTIC);
3973        else if (!strcmp(arg, "--patience"))
3974                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3975        else if (!strcmp(arg, "--histogram"))
3976                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3977        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3978                long value = parse_algorithm_value(optarg);
3979                if (value < 0)
3980                        return error("option diff-algorithm accepts \"myers\", "
3981                                     "\"minimal\", \"patience\" and \"histogram\"");
3982                /* clear out previous settings */
3983                DIFF_XDL_CLR(options, NEED_MINIMAL);
3984                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3985                options->xdl_opts |= value;
3986                return argcount;
3987        }
3988
3989        /* flags options */
3990        else if (!strcmp(arg, "--binary")) {
3991                enable_patch_output(&options->output_format);
3992                DIFF_OPT_SET(options, BINARY);
3993        }
3994        else if (!strcmp(arg, "--full-index"))
3995                DIFF_OPT_SET(options, FULL_INDEX);
3996        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3997                DIFF_OPT_SET(options, TEXT);
3998        else if (!strcmp(arg, "-R"))
3999                DIFF_OPT_SET(options, REVERSE_DIFF);
4000        else if (!strcmp(arg, "--find-copies-harder"))
4001                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4002        else if (!strcmp(arg, "--follow"))
4003                DIFF_OPT_SET(options, FOLLOW_RENAMES);
4004        else if (!strcmp(arg, "--no-follow")) {
4005                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
4006                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
4007        } else if (!strcmp(arg, "--color"))
4008                options->use_color = 1;
4009        else if (skip_prefix(arg, "--color=", &arg)) {
4010                int value = git_config_colorbool(NULL, arg);
4011                if (value < 0)
4012                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
4013                options->use_color = value;
4014        }
4015        else if (!strcmp(arg, "--no-color"))
4016                options->use_color = 0;
4017        else if (!strcmp(arg, "--color-words")) {
4018                options->use_color = 1;
4019                options->word_diff = DIFF_WORDS_COLOR;
4020        }
4021        else if (skip_prefix(arg, "--color-words=", &arg)) {
4022                options->use_color = 1;
4023                options->word_diff = DIFF_WORDS_COLOR;
4024                options->word_regex = arg;
4025        }
4026        else if (!strcmp(arg, "--word-diff")) {
4027                if (options->word_diff == DIFF_WORDS_NONE)
4028                        options->word_diff = DIFF_WORDS_PLAIN;
4029        }
4030        else if (skip_prefix(arg, "--word-diff=", &arg)) {
4031                if (!strcmp(arg, "plain"))
4032                        options->word_diff = DIFF_WORDS_PLAIN;
4033                else if (!strcmp(arg, "color")) {
4034                        options->use_color = 1;
4035                        options->word_diff = DIFF_WORDS_COLOR;
4036                }
4037                else if (!strcmp(arg, "porcelain"))
4038                        options->word_diff = DIFF_WORDS_PORCELAIN;
4039                else if (!strcmp(arg, "none"))
4040                        options->word_diff = DIFF_WORDS_NONE;
4041                else
4042                        die("bad --word-diff argument: %s", arg);
4043        }
4044        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4045                if (options->word_diff == DIFF_WORDS_NONE)
4046                        options->word_diff = DIFF_WORDS_PLAIN;
4047                options->word_regex = optarg;
4048                return argcount;
4049        }
4050        else if (!strcmp(arg, "--exit-code"))
4051                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4052        else if (!strcmp(arg, "--quiet"))
4053                DIFF_OPT_SET(options, QUICK);
4054        else if (!strcmp(arg, "--ext-diff"))
4055                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4056        else if (!strcmp(arg, "--no-ext-diff"))
4057                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4058        else if (!strcmp(arg, "--textconv"))
4059                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4060        else if (!strcmp(arg, "--no-textconv"))
4061                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4062        else if (!strcmp(arg, "--ignore-submodules")) {
4063                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4064                handle_ignore_submodules_arg(options, "all");
4065        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4066                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4067                handle_ignore_submodules_arg(options, arg);
4068        } else if (!strcmp(arg, "--submodule"))
4069                options->submodule_format = DIFF_SUBMODULE_LOG;
4070        else if (skip_prefix(arg, "--submodule=", &arg))
4071                return parse_submodule_opt(options, arg);
4072        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4073                return parse_ws_error_highlight_opt(options, arg);
4074        else if (!strcmp(arg, "--ita-invisible-in-index"))
4075                options->ita_invisible_in_index = 1;
4076        else if (!strcmp(arg, "--ita-visible-in-index"))
4077                options->ita_invisible_in_index = 0;
4078
4079        /* misc options */
4080        else if (!strcmp(arg, "-z"))
4081                options->line_termination = 0;
4082        else if ((argcount = short_opt('l', av, &optarg))) {
4083                options->rename_limit = strtoul(optarg, NULL, 10);
4084                return argcount;
4085        }
4086        else if ((argcount = short_opt('S', av, &optarg))) {
4087                options->pickaxe = optarg;
4088                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4089                return argcount;
4090        } else if ((argcount = short_opt('G', av, &optarg))) {
4091                options->pickaxe = optarg;
4092                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4093                return argcount;
4094        }
4095        else if (!strcmp(arg, "--pickaxe-all"))
4096                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4097        else if (!strcmp(arg, "--pickaxe-regex"))
4098                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4099        else if ((argcount = short_opt('O', av, &optarg))) {
4100                options->orderfile = prefix_filename(prefix, optarg);
4101                return argcount;
4102        }
4103        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4104                int offending = parse_diff_filter_opt(optarg, options);
4105                if (offending)
4106                        die("unknown change class '%c' in --diff-filter=%s",
4107                            offending, optarg);
4108                return argcount;
4109        }
4110        else if (!strcmp(arg, "--no-abbrev"))
4111                options->abbrev = 0;
4112        else if (!strcmp(arg, "--abbrev"))
4113                options->abbrev = DEFAULT_ABBREV;
4114        else if (skip_prefix(arg, "--abbrev=", &arg)) {
4115                options->abbrev = strtoul(arg, NULL, 10);
4116                if (options->abbrev < MINIMUM_ABBREV)
4117                        options->abbrev = MINIMUM_ABBREV;
4118                else if (40 < options->abbrev)
4119                        options->abbrev = 40;
4120        }
4121        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4122                options->a_prefix = optarg;
4123                return argcount;
4124        }
4125        else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4126                options->line_prefix = optarg;
4127                options->line_prefix_length = strlen(options->line_prefix);
4128                graph_setup_line_prefix(options);
4129                return argcount;
4130        }
4131        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4132                options->b_prefix = optarg;
4133                return argcount;
4134        }
4135        else if (!strcmp(arg, "--no-prefix"))
4136                options->a_prefix = options->b_prefix = "";
4137        else if (opt_arg(arg, '\0', "inter-hunk-context",
4138                         &options->interhunkcontext))
4139                ;
4140        else if (!strcmp(arg, "-W"))
4141                DIFF_OPT_SET(options, FUNCCONTEXT);
4142        else if (!strcmp(arg, "--function-context"))
4143                DIFF_OPT_SET(options, FUNCCONTEXT);
4144        else if (!strcmp(arg, "--no-function-context"))
4145                DIFF_OPT_CLR(options, FUNCCONTEXT);
4146        else if ((argcount = parse_long_opt("output", av, &optarg))) {
4147                char *path = prefix_filename(prefix, optarg);
4148                options->file = xfopen(path, "w");
4149                options->close_file = 1;
4150                if (options->use_color != GIT_COLOR_ALWAYS)
4151                        options->use_color = GIT_COLOR_NEVER;
4152                free(path);
4153                return argcount;
4154        } else
4155                return 0;
4156        return 1;
4157}
4158
4159int parse_rename_score(const char **cp_p)
4160{
4161        unsigned long num, scale;
4162        int ch, dot;
4163        const char *cp = *cp_p;
4164
4165        num = 0;
4166        scale = 1;
4167        dot = 0;
4168        for (;;) {
4169                ch = *cp;
4170                if ( !dot && ch == '.' ) {
4171                        scale = 1;
4172                        dot = 1;
4173                } else if ( ch == '%' ) {
4174                        scale = dot ? scale*100 : 100;
4175                        cp++;   /* % is always at the end */
4176                        break;
4177                } else if ( ch >= '0' && ch <= '9' ) {
4178                        if ( scale < 100000 ) {
4179                                scale *= 10;
4180                                num = (num*10) + (ch-'0');
4181                        }
4182                } else {
4183                        break;
4184                }
4185                cp++;
4186        }
4187        *cp_p = cp;
4188
4189        /* user says num divided by scale and we say internally that
4190         * is MAX_SCORE * num / scale.
4191         */
4192        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4193}
4194
4195static int diff_scoreopt_parse(const char *opt)
4196{
4197        int opt1, opt2, cmd;
4198
4199        if (*opt++ != '-')
4200                return -1;
4201        cmd = *opt++;
4202        if (cmd == '-') {
4203                /* convert the long-form arguments into short-form versions */
4204                if (skip_prefix(opt, "break-rewrites", &opt)) {
4205                        if (*opt == 0 || *opt++ == '=')
4206                                cmd = 'B';
4207                } else if (skip_prefix(opt, "find-copies", &opt)) {
4208                        if (*opt == 0 || *opt++ == '=')
4209                                cmd = 'C';
4210                } else if (skip_prefix(opt, "find-renames", &opt)) {
4211                        if (*opt == 0 || *opt++ == '=')
4212                                cmd = 'M';
4213                }
4214        }
4215        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4216                return -1; /* that is not a -M, -C, or -B option */
4217
4218        opt1 = parse_rename_score(&opt);
4219        if (cmd != 'B')
4220                opt2 = 0;
4221        else {
4222                if (*opt == 0)
4223                        opt2 = 0;
4224                else if (*opt != '/')
4225                        return -1; /* we expect -B80/99 or -B80 */
4226                else {
4227                        opt++;
4228                        opt2 = parse_rename_score(&opt);
4229                }
4230        }
4231        if (*opt != 0)
4232                return -1;
4233        return opt1 | (opt2 << 16);
4234}
4235
4236struct diff_queue_struct diff_queued_diff;
4237
4238void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4239{
4240        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4241        queue->queue[queue->nr++] = dp;
4242}
4243
4244struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4245                                 struct diff_filespec *one,
4246                                 struct diff_filespec *two)
4247{
4248        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4249        dp->one = one;
4250        dp->two = two;
4251        if (queue)
4252                diff_q(queue, dp);
4253        return dp;
4254}
4255
4256void diff_free_filepair(struct diff_filepair *p)
4257{
4258        free_filespec(p->one);
4259        free_filespec(p->two);
4260        free(p);
4261}
4262
4263const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4264{
4265        int abblen;
4266        const char *abbrev;
4267
4268        if (len == GIT_SHA1_HEXSZ)
4269                return oid_to_hex(oid);
4270
4271        abbrev = diff_abbrev_oid(oid, len);
4272        abblen = strlen(abbrev);
4273
4274        /*
4275         * In well-behaved cases, where the abbbreviated result is the
4276         * same as the requested length, append three dots after the
4277         * abbreviation (hence the whole logic is limited to the case
4278         * where abblen < 37); when the actual abbreviated result is a
4279         * bit longer than the requested length, we reduce the number
4280         * of dots so that they match the well-behaved ones.  However,
4281         * if the actual abbreviation is longer than the requested
4282         * length by more than three, we give up on aligning, and add
4283         * three dots anyway, to indicate that the output is not the
4284         * full object name.  Yes, this may be suboptimal, but this
4285         * appears only in "diff --raw --abbrev" output and it is not
4286         * worth the effort to change it now.  Note that this would
4287         * likely to work fine when the automatic sizing of default
4288         * abbreviation length is used--we would be fed -1 in "len" in
4289         * that case, and will end up always appending three-dots, but
4290         * the automatic sizing is supposed to give abblen that ensures
4291         * uniqueness across all objects (statistically speaking).
4292         */
4293        if (abblen < GIT_SHA1_HEXSZ - 3) {
4294                static char hex[GIT_MAX_HEXSZ + 1];
4295                if (len < abblen && abblen <= len + 2)
4296                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4297                else
4298                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4299                return hex;
4300        }
4301
4302        return oid_to_hex(oid);
4303}
4304
4305static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4306{
4307        int line_termination = opt->line_termination;
4308        int inter_name_termination = line_termination ? '\t' : '\0';
4309
4310        fprintf(opt->file, "%s", diff_line_prefix(opt));
4311        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4312                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4313                        diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4314                fprintf(opt->file, "%s ",
4315                        diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4316        }
4317        if (p->score) {
4318                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4319                        inter_name_termination);
4320        } else {
4321                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4322        }
4323
4324        if (p->status == DIFF_STATUS_COPIED ||
4325            p->status == DIFF_STATUS_RENAMED) {
4326                const char *name_a, *name_b;
4327                name_a = p->one->path;
4328                name_b = p->two->path;
4329                strip_prefix(opt->prefix_length, &name_a, &name_b);
4330                write_name_quoted(name_a, opt->file, inter_name_termination);
4331                write_name_quoted(name_b, opt->file, line_termination);
4332        } else {
4333                const char *name_a, *name_b;
4334                name_a = p->one->mode ? p->one->path : p->two->path;
4335                name_b = NULL;
4336                strip_prefix(opt->prefix_length, &name_a, &name_b);
4337                write_name_quoted(name_a, opt->file, line_termination);
4338        }
4339}
4340
4341int diff_unmodified_pair(struct diff_filepair *p)
4342{
4343        /* This function is written stricter than necessary to support
4344         * the currently implemented transformers, but the idea is to
4345         * let transformers to produce diff_filepairs any way they want,
4346         * and filter and clean them up here before producing the output.
4347         */
4348        struct diff_filespec *one = p->one, *two = p->two;
4349
4350        if (DIFF_PAIR_UNMERGED(p))
4351                return 0; /* unmerged is interesting */
4352
4353        /* deletion, addition, mode or type change
4354         * and rename are all interesting.
4355         */
4356        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4357            DIFF_PAIR_MODE_CHANGED(p) ||
4358            strcmp(one->path, two->path))
4359                return 0;
4360
4361        /* both are valid and point at the same path.  that is, we are
4362         * dealing with a change.
4363         */
4364        if (one->oid_valid && two->oid_valid &&
4365            !oidcmp(&one->oid, &two->oid) &&
4366            !one->dirty_submodule && !two->dirty_submodule)
4367                return 1; /* no change */
4368        if (!one->oid_valid && !two->oid_valid)
4369                return 1; /* both look at the same file on the filesystem. */
4370        return 0;
4371}
4372
4373static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4374{
4375        if (diff_unmodified_pair(p))
4376                return;
4377
4378        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4379            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4380                return; /* no tree diffs in patch format */
4381
4382        run_diff(p, o);
4383}
4384
4385static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4386                            struct diffstat_t *diffstat)
4387{
4388        if (diff_unmodified_pair(p))
4389                return;
4390
4391        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4392            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4393                return; /* no useful stat for tree diffs */
4394
4395        run_diffstat(p, o, diffstat);
4396}
4397
4398static void diff_flush_checkdiff(struct diff_filepair *p,
4399                struct diff_options *o)
4400{
4401        if (diff_unmodified_pair(p))
4402                return;
4403
4404        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4405            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4406                return; /* nothing to check in tree diffs */
4407
4408        run_checkdiff(p, o);
4409}
4410
4411int diff_queue_is_empty(void)
4412{
4413        struct diff_queue_struct *q = &diff_queued_diff;
4414        int i;
4415        for (i = 0; i < q->nr; i++)
4416                if (!diff_unmodified_pair(q->queue[i]))
4417                        return 0;
4418        return 1;
4419}
4420
4421#if DIFF_DEBUG
4422void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4423{
4424        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4425                x, one ? one : "",
4426                s->path,
4427                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4428                s->mode,
4429                s->oid_valid ? oid_to_hex(&s->oid) : "");
4430        fprintf(stderr, "queue[%d] %s size %lu\n",
4431                x, one ? one : "",
4432                s->size);
4433}
4434
4435void diff_debug_filepair(const struct diff_filepair *p, int i)
4436{
4437        diff_debug_filespec(p->one, i, "one");
4438        diff_debug_filespec(p->two, i, "two");
4439        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4440                p->score, p->status ? p->status : '?',
4441                p->one->rename_used, p->broken_pair);
4442}
4443
4444void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4445{
4446        int i;
4447        if (msg)
4448                fprintf(stderr, "%s\n", msg);
4449        fprintf(stderr, "q->nr = %d\n", q->nr);
4450        for (i = 0; i < q->nr; i++) {
4451                struct diff_filepair *p = q->queue[i];
4452                diff_debug_filepair(p, i);
4453        }
4454}
4455#endif
4456
4457static void diff_resolve_rename_copy(void)
4458{
4459        int i;
4460        struct diff_filepair *p;
4461        struct diff_queue_struct *q = &diff_queued_diff;
4462
4463        diff_debug_queue("resolve-rename-copy", q);
4464
4465        for (i = 0; i < q->nr; i++) {
4466                p = q->queue[i];
4467                p->status = 0; /* undecided */
4468                if (DIFF_PAIR_UNMERGED(p))
4469                        p->status = DIFF_STATUS_UNMERGED;
4470                else if (!DIFF_FILE_VALID(p->one))
4471                        p->status = DIFF_STATUS_ADDED;
4472                else if (!DIFF_FILE_VALID(p->two))
4473                        p->status = DIFF_STATUS_DELETED;
4474                else if (DIFF_PAIR_TYPE_CHANGED(p))
4475                        p->status = DIFF_STATUS_TYPE_CHANGED;
4476
4477                /* from this point on, we are dealing with a pair
4478                 * whose both sides are valid and of the same type, i.e.
4479                 * either in-place edit or rename/copy edit.
4480                 */
4481                else if (DIFF_PAIR_RENAME(p)) {
4482                        /*
4483                         * A rename might have re-connected a broken
4484                         * pair up, causing the pathnames to be the
4485                         * same again. If so, that's not a rename at
4486                         * all, just a modification..
4487                         *
4488                         * Otherwise, see if this source was used for
4489                         * multiple renames, in which case we decrement
4490                         * the count, and call it a copy.
4491                         */
4492                        if (!strcmp(p->one->path, p->two->path))
4493                                p->status = DIFF_STATUS_MODIFIED;
4494                        else if (--p->one->rename_used > 0)
4495                                p->status = DIFF_STATUS_COPIED;
4496                        else
4497                                p->status = DIFF_STATUS_RENAMED;
4498                }
4499                else if (oidcmp(&p->one->oid, &p->two->oid) ||
4500                         p->one->mode != p->two->mode ||
4501                         p->one->dirty_submodule ||
4502                         p->two->dirty_submodule ||
4503                         is_null_oid(&p->one->oid))
4504                        p->status = DIFF_STATUS_MODIFIED;
4505                else {
4506                        /* This is a "no-change" entry and should not
4507                         * happen anymore, but prepare for broken callers.
4508                         */
4509                        error("feeding unmodified %s to diffcore",
4510                              p->one->path);
4511                        p->status = DIFF_STATUS_UNKNOWN;
4512                }
4513        }
4514        diff_debug_queue("resolve-rename-copy done", q);
4515}
4516
4517static int check_pair_status(struct diff_filepair *p)
4518{
4519        switch (p->status) {
4520        case DIFF_STATUS_UNKNOWN:
4521                return 0;
4522        case 0:
4523                die("internal error in diff-resolve-rename-copy");
4524        default:
4525                return 1;
4526        }
4527}
4528
4529static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4530{
4531        int fmt = opt->output_format;
4532
4533        if (fmt & DIFF_FORMAT_CHECKDIFF)
4534                diff_flush_checkdiff(p, opt);
4535        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4536                diff_flush_raw(p, opt);
4537        else if (fmt & DIFF_FORMAT_NAME) {
4538                const char *name_a, *name_b;
4539                name_a = p->two->path;
4540                name_b = NULL;
4541                strip_prefix(opt->prefix_length, &name_a, &name_b);
4542                fprintf(opt->file, "%s", diff_line_prefix(opt));
4543                write_name_quoted(name_a, opt->file, opt->line_termination);
4544        }
4545}
4546
4547static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4548{
4549        if (fs->mode)
4550                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4551        else
4552                fprintf(file, " %s ", newdelete);
4553        write_name_quoted(fs->path, file, '\n');
4554}
4555
4556
4557static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4558                const char *line_prefix)
4559{
4560        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4561                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4562                        p->two->mode, show_name ? ' ' : '\n');
4563                if (show_name) {
4564                        write_name_quoted(p->two->path, file, '\n');
4565                }
4566        }
4567}
4568
4569static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4570                        const char *line_prefix)
4571{
4572        char *names = pprint_rename(p->one->path, p->two->path);
4573
4574        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4575        free(names);
4576        show_mode_change(file, p, 0, line_prefix);
4577}
4578
4579static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4580{
4581        FILE *file = opt->file;
4582        const char *line_prefix = diff_line_prefix(opt);
4583
4584        switch(p->status) {
4585        case DIFF_STATUS_DELETED:
4586                fputs(line_prefix, file);
4587                show_file_mode_name(file, "delete", p->one);
4588                break;
4589        case DIFF_STATUS_ADDED:
4590                fputs(line_prefix, file);
4591                show_file_mode_name(file, "create", p->two);
4592                break;
4593        case DIFF_STATUS_COPIED:
4594                fputs(line_prefix, file);
4595                show_rename_copy(file, "copy", p, line_prefix);
4596                break;
4597        case DIFF_STATUS_RENAMED:
4598                fputs(line_prefix, file);
4599                show_rename_copy(file, "rename", p, line_prefix);
4600                break;
4601        default:
4602                if (p->score) {
4603                        fprintf(file, "%s rewrite ", line_prefix);
4604                        write_name_quoted(p->two->path, file, ' ');
4605                        fprintf(file, "(%d%%)\n", similarity_index(p));
4606                }
4607                show_mode_change(file, p, !p->score, line_prefix);
4608                break;
4609        }
4610}
4611
4612struct patch_id_t {
4613        git_SHA_CTX *ctx;
4614        int patchlen;
4615};
4616
4617static int remove_space(char *line, int len)
4618{
4619        int i;
4620        char *dst = line;
4621        unsigned char c;
4622
4623        for (i = 0; i < len; i++)
4624                if (!isspace((c = line[i])))
4625                        *dst++ = c;
4626
4627        return dst - line;
4628}
4629
4630static void patch_id_consume(void *priv, char *line, unsigned long len)
4631{
4632        struct patch_id_t *data = priv;
4633        int new_len;
4634
4635        /* Ignore line numbers when computing the SHA1 of the patch */
4636        if (starts_with(line, "@@ -"))
4637                return;
4638
4639        new_len = remove_space(line, len);
4640
4641        git_SHA1_Update(data->ctx, line, new_len);
4642        data->patchlen += new_len;
4643}
4644
4645static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4646{
4647        git_SHA1_Update(ctx, str, strlen(str));
4648}
4649
4650static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4651{
4652        /* large enough for 2^32 in octal */
4653        char buf[12];
4654        int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4655        git_SHA1_Update(ctx, buf, len);
4656}
4657
4658/* returns 0 upon success, and writes result into sha1 */
4659static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4660{
4661        struct diff_queue_struct *q = &diff_queued_diff;
4662        int i;
4663        git_SHA_CTX ctx;
4664        struct patch_id_t data;
4665
4666        git_SHA1_Init(&ctx);
4667        memset(&data, 0, sizeof(struct patch_id_t));
4668        data.ctx = &ctx;
4669
4670        for (i = 0; i < q->nr; i++) {
4671                xpparam_t xpp;
4672                xdemitconf_t xecfg;
4673                mmfile_t mf1, mf2;
4674                struct diff_filepair *p = q->queue[i];
4675                int len1, len2;
4676
4677                memset(&xpp, 0, sizeof(xpp));
4678                memset(&xecfg, 0, sizeof(xecfg));
4679                if (p->status == 0)
4680                        return error("internal diff status error");
4681                if (p->status == DIFF_STATUS_UNKNOWN)
4682                        continue;
4683                if (diff_unmodified_pair(p))
4684                        continue;
4685                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4686                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4687                        continue;
4688                if (DIFF_PAIR_UNMERGED(p))
4689                        continue;
4690
4691                diff_fill_oid_info(p->one);
4692                diff_fill_oid_info(p->two);
4693
4694                len1 = remove_space(p->one->path, strlen(p->one->path));
4695                len2 = remove_space(p->two->path, strlen(p->two->path));
4696                patch_id_add_string(&ctx, "diff--git");
4697                patch_id_add_string(&ctx, "a/");
4698                git_SHA1_Update(&ctx, p->one->path, len1);
4699                patch_id_add_string(&ctx, "b/");
4700                git_SHA1_Update(&ctx, p->two->path, len2);
4701
4702                if (p->one->mode == 0) {
4703                        patch_id_add_string(&ctx, "newfilemode");
4704                        patch_id_add_mode(&ctx, p->two->mode);
4705                        patch_id_add_string(&ctx, "---/dev/null");
4706                        patch_id_add_string(&ctx, "+++b/");
4707                        git_SHA1_Update(&ctx, p->two->path, len2);
4708                } else if (p->two->mode == 0) {
4709                        patch_id_add_string(&ctx, "deletedfilemode");
4710                        patch_id_add_mode(&ctx, p->one->mode);
4711                        patch_id_add_string(&ctx, "---a/");
4712                        git_SHA1_Update(&ctx, p->one->path, len1);
4713                        patch_id_add_string(&ctx, "+++/dev/null");
4714                } else {
4715                        patch_id_add_string(&ctx, "---a/");
4716                        git_SHA1_Update(&ctx, p->one->path, len1);
4717                        patch_id_add_string(&ctx, "+++b/");
4718                        git_SHA1_Update(&ctx, p->two->path, len2);
4719                }
4720
4721                if (diff_header_only)
4722                        continue;
4723
4724                if (fill_mmfile(&mf1, p->one) < 0 ||
4725                    fill_mmfile(&mf2, p->two) < 0)
4726                        return error("unable to read files to diff");
4727
4728                if (diff_filespec_is_binary(p->one) ||
4729                    diff_filespec_is_binary(p->two)) {
4730                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4731                                        GIT_SHA1_HEXSZ);
4732                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4733                                        GIT_SHA1_HEXSZ);
4734                        continue;
4735                }
4736
4737                xpp.flags = 0;
4738                xecfg.ctxlen = 3;
4739                xecfg.flags = 0;
4740                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4741                                  &xpp, &xecfg))
4742                        return error("unable to generate patch-id diff for %s",
4743                                     p->one->path);
4744        }
4745
4746        git_SHA1_Final(oid->hash, &ctx);
4747        return 0;
4748}
4749
4750int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4751{
4752        struct diff_queue_struct *q = &diff_queued_diff;
4753        int i;
4754        int result = diff_get_patch_id(options, oid, diff_header_only);
4755
4756        for (i = 0; i < q->nr; i++)
4757                diff_free_filepair(q->queue[i]);
4758
4759        free(q->queue);
4760        DIFF_QUEUE_CLEAR(q);
4761
4762        return result;
4763}
4764
4765static int is_summary_empty(const struct diff_queue_struct *q)
4766{
4767        int i;
4768
4769        for (i = 0; i < q->nr; i++) {
4770                const struct diff_filepair *p = q->queue[i];
4771
4772                switch (p->status) {
4773                case DIFF_STATUS_DELETED:
4774                case DIFF_STATUS_ADDED:
4775                case DIFF_STATUS_COPIED:
4776                case DIFF_STATUS_RENAMED:
4777                        return 0;
4778                default:
4779                        if (p->score)
4780                                return 0;
4781                        if (p->one->mode && p->two->mode &&
4782                            p->one->mode != p->two->mode)
4783                                return 0;
4784                        break;
4785                }
4786        }
4787        return 1;
4788}
4789
4790static const char rename_limit_warning[] =
4791N_("inexact rename detection was skipped due to too many files.");
4792
4793static const char degrade_cc_to_c_warning[] =
4794N_("only found copies from modified paths due to too many files.");
4795
4796static const char rename_limit_advice[] =
4797N_("you may want to set your %s variable to at least "
4798   "%d and retry the command.");
4799
4800void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4801{
4802        if (degraded_cc)
4803                warning(_(degrade_cc_to_c_warning));
4804        else if (needed)
4805                warning(_(rename_limit_warning));
4806        else
4807                return;
4808        if (0 < needed && needed < 32767)
4809                warning(_(rename_limit_advice), varname, needed);
4810}
4811
4812static void diff_flush_patch_all_file_pairs(struct diff_options *o)
4813{
4814        int i;
4815        struct diff_queue_struct *q = &diff_queued_diff;
4816
4817        if (WSEH_NEW & WS_RULE_MASK)
4818                die("BUG: WS rules bit mask overlaps with diff symbol flags");
4819
4820        for (i = 0; i < q->nr; i++) {
4821                struct diff_filepair *p = q->queue[i];
4822                if (check_pair_status(p))
4823                        diff_flush_patch(p, o);
4824        }
4825}
4826
4827void diff_flush(struct diff_options *options)
4828{
4829        struct diff_queue_struct *q = &diff_queued_diff;
4830        int i, output_format = options->output_format;
4831        int separator = 0;
4832        int dirstat_by_line = 0;
4833
4834        /*
4835         * Order: raw, stat, summary, patch
4836         * or:    name/name-status/checkdiff (other bits clear)
4837         */
4838        if (!q->nr)
4839                goto free_queue;
4840
4841        if (output_format & (DIFF_FORMAT_RAW |
4842                             DIFF_FORMAT_NAME |
4843                             DIFF_FORMAT_NAME_STATUS |
4844                             DIFF_FORMAT_CHECKDIFF)) {
4845                for (i = 0; i < q->nr; i++) {
4846                        struct diff_filepair *p = q->queue[i];
4847                        if (check_pair_status(p))
4848                                flush_one_pair(p, options);
4849                }
4850                separator++;
4851        }
4852
4853        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4854                dirstat_by_line = 1;
4855
4856        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4857            dirstat_by_line) {
4858                struct diffstat_t diffstat;
4859
4860                memset(&diffstat, 0, sizeof(struct diffstat_t));
4861                for (i = 0; i < q->nr; i++) {
4862                        struct diff_filepair *p = q->queue[i];
4863                        if (check_pair_status(p))
4864                                diff_flush_stat(p, options, &diffstat);
4865                }
4866                if (output_format & DIFF_FORMAT_NUMSTAT)
4867                        show_numstat(&diffstat, options);
4868                if (output_format & DIFF_FORMAT_DIFFSTAT)
4869                        show_stats(&diffstat, options);
4870                if (output_format & DIFF_FORMAT_SHORTSTAT)
4871                        show_shortstats(&diffstat, options);
4872                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4873                        show_dirstat_by_line(&diffstat, options);
4874                free_diffstat_info(&diffstat);
4875                separator++;
4876        }
4877        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4878                show_dirstat(options);
4879
4880        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4881                for (i = 0; i < q->nr; i++) {
4882                        diff_summary(options, q->queue[i]);
4883                }
4884                separator++;
4885        }
4886
4887        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4888            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4889            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4890                /*
4891                 * run diff_flush_patch for the exit status. setting
4892                 * options->file to /dev/null should be safe, because we
4893                 * aren't supposed to produce any output anyway.
4894                 */
4895                if (options->close_file)
4896                        fclose(options->file);
4897                options->file = xfopen("/dev/null", "w");
4898                options->close_file = 1;
4899                for (i = 0; i < q->nr; i++) {
4900                        struct diff_filepair *p = q->queue[i];
4901                        if (check_pair_status(p))
4902                                diff_flush_patch(p, options);
4903                        if (options->found_changes)
4904                                break;
4905                }
4906        }
4907
4908        if (output_format & DIFF_FORMAT_PATCH) {
4909                if (separator) {
4910                        emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
4911                        if (options->stat_sep) {
4912                                /* attach patch instead of inline */
4913                                fputs(options->stat_sep, options->file);
4914                        }
4915                }
4916
4917                diff_flush_patch_all_file_pairs(options);
4918        }
4919
4920        if (output_format & DIFF_FORMAT_CALLBACK)
4921                options->format_callback(q, options, options->format_callback_data);
4922
4923        for (i = 0; i < q->nr; i++)
4924                diff_free_filepair(q->queue[i]);
4925free_queue:
4926        free(q->queue);
4927        DIFF_QUEUE_CLEAR(q);
4928        if (options->close_file)
4929                fclose(options->file);
4930
4931        /*
4932         * Report the content-level differences with HAS_CHANGES;
4933         * diff_addremove/diff_change does not set the bit when
4934         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4935         */
4936        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4937                if (options->found_changes)
4938                        DIFF_OPT_SET(options, HAS_CHANGES);
4939                else
4940                        DIFF_OPT_CLR(options, HAS_CHANGES);
4941        }
4942}
4943
4944static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4945{
4946        return (((p->status == DIFF_STATUS_MODIFIED) &&
4947                 ((p->score &&
4948                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4949                  (!p->score &&
4950                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4951                ((p->status != DIFF_STATUS_MODIFIED) &&
4952                 filter_bit_tst(p->status, options)));
4953}
4954
4955static void diffcore_apply_filter(struct diff_options *options)
4956{
4957        int i;
4958        struct diff_queue_struct *q = &diff_queued_diff;
4959        struct diff_queue_struct outq;
4960
4961        DIFF_QUEUE_CLEAR(&outq);
4962
4963        if (!options->filter)
4964                return;
4965
4966        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4967                int found;
4968                for (i = found = 0; !found && i < q->nr; i++) {
4969                        if (match_filter(options, q->queue[i]))
4970                                found++;
4971                }
4972                if (found)
4973                        return;
4974
4975                /* otherwise we will clear the whole queue
4976                 * by copying the empty outq at the end of this
4977                 * function, but first clear the current entries
4978                 * in the queue.
4979                 */
4980                for (i = 0; i < q->nr; i++)
4981                        diff_free_filepair(q->queue[i]);
4982        }
4983        else {
4984                /* Only the matching ones */
4985                for (i = 0; i < q->nr; i++) {
4986                        struct diff_filepair *p = q->queue[i];
4987                        if (match_filter(options, p))
4988                                diff_q(&outq, p);
4989                        else
4990                                diff_free_filepair(p);
4991                }
4992        }
4993        free(q->queue);
4994        *q = outq;
4995}
4996
4997/* Check whether two filespecs with the same mode and size are identical */
4998static int diff_filespec_is_identical(struct diff_filespec *one,
4999                                      struct diff_filespec *two)
5000{
5001        if (S_ISGITLINK(one->mode))
5002                return 0;
5003        if (diff_populate_filespec(one, 0))
5004                return 0;
5005        if (diff_populate_filespec(two, 0))
5006                return 0;
5007        return !memcmp(one->data, two->data, one->size);
5008}
5009
5010static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5011{
5012        if (p->done_skip_stat_unmatch)
5013                return p->skip_stat_unmatch_result;
5014
5015        p->done_skip_stat_unmatch = 1;
5016        p->skip_stat_unmatch_result = 0;
5017        /*
5018         * 1. Entries that come from stat info dirtiness
5019         *    always have both sides (iow, not create/delete),
5020         *    one side of the object name is unknown, with
5021         *    the same mode and size.  Keep the ones that
5022         *    do not match these criteria.  They have real
5023         *    differences.
5024         *
5025         * 2. At this point, the file is known to be modified,
5026         *    with the same mode and size, and the object
5027         *    name of one side is unknown.  Need to inspect
5028         *    the identical contents.
5029         */
5030        if (!DIFF_FILE_VALID(p->one) || /* (1) */
5031            !DIFF_FILE_VALID(p->two) ||
5032            (p->one->oid_valid && p->two->oid_valid) ||
5033            (p->one->mode != p->two->mode) ||
5034            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5035            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5036            (p->one->size != p->two->size) ||
5037            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5038                p->skip_stat_unmatch_result = 1;
5039        return p->skip_stat_unmatch_result;
5040}
5041
5042static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5043{
5044        int i;
5045        struct diff_queue_struct *q = &diff_queued_diff;
5046        struct diff_queue_struct outq;
5047        DIFF_QUEUE_CLEAR(&outq);
5048
5049        for (i = 0; i < q->nr; i++) {
5050                struct diff_filepair *p = q->queue[i];
5051
5052                if (diff_filespec_check_stat_unmatch(p))
5053                        diff_q(&outq, p);
5054                else {
5055                        /*
5056                         * The caller can subtract 1 from skip_stat_unmatch
5057                         * to determine how many paths were dirty only
5058                         * due to stat info mismatch.
5059                         */
5060                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5061                                diffopt->skip_stat_unmatch++;
5062                        diff_free_filepair(p);
5063                }
5064        }
5065        free(q->queue);
5066        *q = outq;
5067}
5068
5069static int diffnamecmp(const void *a_, const void *b_)
5070{
5071        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5072        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5073        const char *name_a, *name_b;
5074
5075        name_a = a->one ? a->one->path : a->two->path;
5076        name_b = b->one ? b->one->path : b->two->path;
5077        return strcmp(name_a, name_b);
5078}
5079
5080void diffcore_fix_diff_index(struct diff_options *options)
5081{
5082        struct diff_queue_struct *q = &diff_queued_diff;
5083        QSORT(q->queue, q->nr, diffnamecmp);
5084}
5085
5086void diffcore_std(struct diff_options *options)
5087{
5088        /* NOTE please keep the following in sync with diff_tree_combined() */
5089        if (options->skip_stat_unmatch)
5090                diffcore_skip_stat_unmatch(options);
5091        if (!options->found_follow) {
5092                /* See try_to_follow_renames() in tree-diff.c */
5093                if (options->break_opt != -1)
5094                        diffcore_break(options->break_opt);
5095                if (options->detect_rename)
5096                        diffcore_rename(options);
5097                if (options->break_opt != -1)
5098                        diffcore_merge_broken();
5099        }
5100        if (options->pickaxe)
5101                diffcore_pickaxe(options);
5102        if (options->orderfile)
5103                diffcore_order(options->orderfile);
5104        if (!options->found_follow)
5105                /* See try_to_follow_renames() in tree-diff.c */
5106                diff_resolve_rename_copy();
5107        diffcore_apply_filter(options);
5108
5109        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5110                DIFF_OPT_SET(options, HAS_CHANGES);
5111        else
5112                DIFF_OPT_CLR(options, HAS_CHANGES);
5113
5114        options->found_follow = 0;
5115}
5116
5117int diff_result_code(struct diff_options *opt, int status)
5118{
5119        int result = 0;
5120
5121        diff_warn_rename_limit("diff.renameLimit",
5122                               opt->needed_rename_limit,
5123                               opt->degraded_cc_to_c);
5124        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5125            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5126                return status;
5127        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5128            DIFF_OPT_TST(opt, HAS_CHANGES))
5129                result |= 01;
5130        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5131            DIFF_OPT_TST(opt, CHECK_FAILED))
5132                result |= 02;
5133        return result;
5134}
5135
5136int diff_can_quit_early(struct diff_options *opt)
5137{
5138        return (DIFF_OPT_TST(opt, QUICK) &&
5139                !opt->filter &&
5140                DIFF_OPT_TST(opt, HAS_CHANGES));
5141}
5142
5143/*
5144 * Shall changes to this submodule be ignored?
5145 *
5146 * Submodule changes can be configured to be ignored separately for each path,
5147 * but that configuration can be overridden from the command line.
5148 */
5149static int is_submodule_ignored(const char *path, struct diff_options *options)
5150{
5151        int ignored = 0;
5152        unsigned orig_flags = options->flags;
5153        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5154                set_diffopt_flags_from_submodule_config(options, path);
5155        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5156                ignored = 1;
5157        options->flags = orig_flags;
5158        return ignored;
5159}
5160
5161void diff_addremove(struct diff_options *options,
5162                    int addremove, unsigned mode,
5163                    const struct object_id *oid,
5164                    int oid_valid,
5165                    const char *concatpath, unsigned dirty_submodule)
5166{
5167        struct diff_filespec *one, *two;
5168
5169        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5170                return;
5171
5172        /* This may look odd, but it is a preparation for
5173         * feeding "there are unchanged files which should
5174         * not produce diffs, but when you are doing copy
5175         * detection you would need them, so here they are"
5176         * entries to the diff-core.  They will be prefixed
5177         * with something like '=' or '*' (I haven't decided
5178         * which but should not make any difference).
5179         * Feeding the same new and old to diff_change()
5180         * also has the same effect.
5181         * Before the final output happens, they are pruned after
5182         * merged into rename/copy pairs as appropriate.
5183         */
5184        if (DIFF_OPT_TST(options, REVERSE_DIFF))
5185                addremove = (addremove == '+' ? '-' :
5186                             addremove == '-' ? '+' : addremove);
5187
5188        if (options->prefix &&
5189            strncmp(concatpath, options->prefix, options->prefix_length))
5190                return;
5191
5192        one = alloc_filespec(concatpath);
5193        two = alloc_filespec(concatpath);
5194
5195        if (addremove != '+')
5196                fill_filespec(one, oid, oid_valid, mode);
5197        if (addremove != '-') {
5198                fill_filespec(two, oid, oid_valid, mode);
5199                two->dirty_submodule = dirty_submodule;
5200        }
5201
5202        diff_queue(&diff_queued_diff, one, two);
5203        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5204                DIFF_OPT_SET(options, HAS_CHANGES);
5205}
5206
5207void diff_change(struct diff_options *options,
5208                 unsigned old_mode, unsigned new_mode,
5209                 const struct object_id *old_oid,
5210                 const struct object_id *new_oid,
5211                 int old_oid_valid, int new_oid_valid,
5212                 const char *concatpath,
5213                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5214{
5215        struct diff_filespec *one, *two;
5216        struct diff_filepair *p;
5217
5218        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5219            is_submodule_ignored(concatpath, options))
5220                return;
5221
5222        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5223                SWAP(old_mode, new_mode);
5224                SWAP(old_oid, new_oid);
5225                SWAP(old_oid_valid, new_oid_valid);
5226                SWAP(old_dirty_submodule, new_dirty_submodule);
5227        }
5228
5229        if (options->prefix &&
5230            strncmp(concatpath, options->prefix, options->prefix_length))
5231                return;
5232
5233        one = alloc_filespec(concatpath);
5234        two = alloc_filespec(concatpath);
5235        fill_filespec(one, old_oid, old_oid_valid, old_mode);
5236        fill_filespec(two, new_oid, new_oid_valid, new_mode);
5237        one->dirty_submodule = old_dirty_submodule;
5238        two->dirty_submodule = new_dirty_submodule;
5239        p = diff_queue(&diff_queued_diff, one, two);
5240
5241        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5242                return;
5243
5244        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5245            !diff_filespec_check_stat_unmatch(p))
5246                return;
5247
5248        DIFF_OPT_SET(options, HAS_CHANGES);
5249}
5250
5251struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5252{
5253        struct diff_filepair *pair;
5254        struct diff_filespec *one, *two;
5255
5256        if (options->prefix &&
5257            strncmp(path, options->prefix, options->prefix_length))
5258                return NULL;
5259
5260        one = alloc_filespec(path);
5261        two = alloc_filespec(path);
5262        pair = diff_queue(&diff_queued_diff, one, two);
5263        pair->is_unmerged = 1;
5264        return pair;
5265}
5266
5267static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5268                size_t *outsize)
5269{
5270        struct diff_tempfile *temp;
5271        const char *argv[3];
5272        const char **arg = argv;
5273        struct child_process child = CHILD_PROCESS_INIT;
5274        struct strbuf buf = STRBUF_INIT;
5275        int err = 0;
5276
5277        temp = prepare_temp_file(spec->path, spec);
5278        *arg++ = pgm;
5279        *arg++ = temp->name;
5280        *arg = NULL;
5281
5282        child.use_shell = 1;
5283        child.argv = argv;
5284        child.out = -1;
5285        if (start_command(&child)) {
5286                remove_tempfile();
5287                return NULL;
5288        }
5289
5290        if (strbuf_read(&buf, child.out, 0) < 0)
5291                err = error("error reading from textconv command '%s'", pgm);
5292        close(child.out);
5293
5294        if (finish_command(&child) || err) {
5295                strbuf_release(&buf);
5296                remove_tempfile();
5297                return NULL;
5298        }
5299        remove_tempfile();
5300
5301        return strbuf_detach(&buf, outsize);
5302}
5303
5304size_t fill_textconv(struct userdiff_driver *driver,
5305                     struct diff_filespec *df,
5306                     char **outbuf)
5307{
5308        size_t size;
5309
5310        if (!driver) {
5311                if (!DIFF_FILE_VALID(df)) {
5312                        *outbuf = "";
5313                        return 0;
5314                }
5315                if (diff_populate_filespec(df, 0))
5316                        die("unable to read files to diff");
5317                *outbuf = df->data;
5318                return df->size;
5319        }
5320
5321        if (!driver->textconv)
5322                die("BUG: fill_textconv called with non-textconv driver");
5323
5324        if (driver->textconv_cache && df->oid_valid) {
5325                *outbuf = notes_cache_get(driver->textconv_cache,
5326                                          &df->oid,
5327                                          &size);
5328                if (*outbuf)
5329                        return size;
5330        }
5331
5332        *outbuf = run_textconv(driver->textconv, df, &size);
5333        if (!*outbuf)
5334                die("unable to read files to diff");
5335
5336        if (driver->textconv_cache && df->oid_valid) {
5337                /* ignore errors, as we might be in a readonly repository */
5338                notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
5339                                size);
5340                /*
5341                 * we could save up changes and flush them all at the end,
5342                 * but we would need an extra call after all diffing is done.
5343                 * Since generating a cache entry is the slow path anyway,
5344                 * this extra overhead probably isn't a big deal.
5345                 */
5346                notes_cache_write(driver->textconv_cache);
5347        }
5348
5349        return size;
5350}
5351
5352int textconv_object(const char *path,
5353                    unsigned mode,
5354                    const struct object_id *oid,
5355                    int oid_valid,
5356                    char **buf,
5357                    unsigned long *buf_size)
5358{
5359        struct diff_filespec *df;
5360        struct userdiff_driver *textconv;
5361
5362        df = alloc_filespec(path);
5363        fill_filespec(df, oid, oid_valid, mode);
5364        textconv = get_textconv(df);
5365        if (!textconv) {
5366                free_filespec(df);
5367                return 0;
5368        }
5369
5370        *buf_size = fill_textconv(textconv, df, buf);
5371        free_filespec(df);
5372        return 1;
5373}
5374
5375void setup_diff_pager(struct diff_options *opt)
5376{
5377        /*
5378         * If the user asked for our exit code, then either they want --quiet
5379         * or --exit-code. We should definitely not bother with a pager in the
5380         * former case, as we will generate no output. Since we still properly
5381         * report our exit code even when a pager is run, we _could_ run a
5382         * pager with --exit-code. But since we have not done so historically,
5383         * and because it is easy to find people oneline advising "git diff
5384         * --exit-code" in hooks and other scripts, we do not do so.
5385         */
5386        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5387            check_pager_config("diff") != 0)
5388                setup_pager();
5389}