diff.con commit Merge branch 'jt/format-patch-base-info-above-sig' into maint (7b7e977)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "tempfile.h"
   6#include "quote.h"
   7#include "diff.h"
   8#include "diffcore.h"
   9#include "delta.h"
  10#include "xdiff-interface.h"
  11#include "color.h"
  12#include "attr.h"
  13#include "run-command.h"
  14#include "utf8.h"
  15#include "userdiff.h"
  16#include "submodule-config.h"
  17#include "submodule.h"
  18#include "ll-merge.h"
  19#include "string-list.h"
  20#include "argv-array.h"
  21
  22#ifdef NO_FAST_WORKING_DIRECTORY
  23#define FAST_WORKING_DIRECTORY 0
  24#else
  25#define FAST_WORKING_DIRECTORY 1
  26#endif
  27
  28static int diff_detect_rename_default;
  29static int diff_compaction_heuristic; /* experimental */
  30static int diff_rename_limit_default = 400;
  31static int diff_suppress_blank_empty;
  32static int diff_use_color_default = -1;
  33static int diff_context_default = 3;
  34static const char *diff_word_regex_cfg;
  35static const char *external_diff_cmd_cfg;
  36static const char *diff_order_file_cfg;
  37int diff_auto_refresh_index = 1;
  38static int diff_mnemonic_prefix;
  39static int diff_no_prefix;
  40static int diff_stat_graph_width;
  41static int diff_dirstat_permille_default = 30;
  42static struct diff_options default_diff_options;
  43static long diff_algorithm;
  44
  45static char diff_colors[][COLOR_MAXLEN] = {
  46        GIT_COLOR_RESET,
  47        GIT_COLOR_NORMAL,       /* CONTEXT */
  48        GIT_COLOR_BOLD,         /* METAINFO */
  49        GIT_COLOR_CYAN,         /* FRAGINFO */
  50        GIT_COLOR_RED,          /* OLD */
  51        GIT_COLOR_GREEN,        /* NEW */
  52        GIT_COLOR_YELLOW,       /* COMMIT */
  53        GIT_COLOR_BG_RED,       /* WHITESPACE */
  54        GIT_COLOR_NORMAL,       /* FUNCINFO */
  55};
  56
  57static int parse_diff_color_slot(const char *var)
  58{
  59        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  60                return DIFF_CONTEXT;
  61        if (!strcasecmp(var, "meta"))
  62                return DIFF_METAINFO;
  63        if (!strcasecmp(var, "frag"))
  64                return DIFF_FRAGINFO;
  65        if (!strcasecmp(var, "old"))
  66                return DIFF_FILE_OLD;
  67        if (!strcasecmp(var, "new"))
  68                return DIFF_FILE_NEW;
  69        if (!strcasecmp(var, "commit"))
  70                return DIFF_COMMIT;
  71        if (!strcasecmp(var, "whitespace"))
  72                return DIFF_WHITESPACE;
  73        if (!strcasecmp(var, "func"))
  74                return DIFF_FUNCINFO;
  75        return -1;
  76}
  77
  78static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  79                                struct strbuf *errmsg)
  80{
  81        char *params_copy = xstrdup(params_string);
  82        struct string_list params = STRING_LIST_INIT_NODUP;
  83        int ret = 0;
  84        int i;
  85
  86        if (*params_copy)
  87                string_list_split_in_place(&params, params_copy, ',', -1);
  88        for (i = 0; i < params.nr; i++) {
  89                const char *p = params.items[i].string;
  90                if (!strcmp(p, "changes")) {
  91                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  92                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  93                } else if (!strcmp(p, "lines")) {
  94                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  95                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  96                } else if (!strcmp(p, "files")) {
  97                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  98                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  99                } else if (!strcmp(p, "noncumulative")) {
 100                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 101                } else if (!strcmp(p, "cumulative")) {
 102                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 103                } else if (isdigit(*p)) {
 104                        char *end;
 105                        int permille = strtoul(p, &end, 10) * 10;
 106                        if (*end == '.' && isdigit(*++end)) {
 107                                /* only use first digit */
 108                                permille += *end - '0';
 109                                /* .. and ignore any further digits */
 110                                while (isdigit(*++end))
 111                                        ; /* nothing */
 112                        }
 113                        if (!*end)
 114                                options->dirstat_permille = permille;
 115                        else {
 116                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 117                                            p);
 118                                ret++;
 119                        }
 120                } else {
 121                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 122                        ret++;
 123                }
 124
 125        }
 126        string_list_clear(&params, 0);
 127        free(params_copy);
 128        return ret;
 129}
 130
 131static int parse_submodule_params(struct diff_options *options, const char *value)
 132{
 133        if (!strcmp(value, "log"))
 134                DIFF_OPT_SET(options, SUBMODULE_LOG);
 135        else if (!strcmp(value, "short"))
 136                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 137        else
 138                return -1;
 139        return 0;
 140}
 141
 142static int git_config_rename(const char *var, const char *value)
 143{
 144        if (!value)
 145                return DIFF_DETECT_RENAME;
 146        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 147                return  DIFF_DETECT_COPY;
 148        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 149}
 150
 151long parse_algorithm_value(const char *value)
 152{
 153        if (!value)
 154                return -1;
 155        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 156                return 0;
 157        else if (!strcasecmp(value, "minimal"))
 158                return XDF_NEED_MINIMAL;
 159        else if (!strcasecmp(value, "patience"))
 160                return XDF_PATIENCE_DIFF;
 161        else if (!strcasecmp(value, "histogram"))
 162                return XDF_HISTOGRAM_DIFF;
 163        return -1;
 164}
 165
 166/*
 167 * These are to give UI layer defaults.
 168 * The core-level commands such as git-diff-files should
 169 * never be affected by the setting of diff.renames
 170 * the user happens to have in the configuration file.
 171 */
 172void init_diff_ui_defaults(void)
 173{
 174        diff_detect_rename_default = 1;
 175}
 176
 177int git_diff_ui_config(const char *var, const char *value, void *cb)
 178{
 179        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 180                diff_use_color_default = git_config_colorbool(var, value);
 181                return 0;
 182        }
 183        if (!strcmp(var, "diff.context")) {
 184                diff_context_default = git_config_int(var, value);
 185                if (diff_context_default < 0)
 186                        return -1;
 187                return 0;
 188        }
 189        if (!strcmp(var, "diff.renames")) {
 190                diff_detect_rename_default = git_config_rename(var, value);
 191                return 0;
 192        }
 193        if (!strcmp(var, "diff.compactionheuristic")) {
 194                diff_compaction_heuristic = git_config_bool(var, value);
 195                return 0;
 196        }
 197        if (!strcmp(var, "diff.autorefreshindex")) {
 198                diff_auto_refresh_index = git_config_bool(var, value);
 199                return 0;
 200        }
 201        if (!strcmp(var, "diff.mnemonicprefix")) {
 202                diff_mnemonic_prefix = git_config_bool(var, value);
 203                return 0;
 204        }
 205        if (!strcmp(var, "diff.noprefix")) {
 206                diff_no_prefix = git_config_bool(var, value);
 207                return 0;
 208        }
 209        if (!strcmp(var, "diff.statgraphwidth")) {
 210                diff_stat_graph_width = git_config_int(var, value);
 211                return 0;
 212        }
 213        if (!strcmp(var, "diff.external"))
 214                return git_config_string(&external_diff_cmd_cfg, var, value);
 215        if (!strcmp(var, "diff.wordregex"))
 216                return git_config_string(&diff_word_regex_cfg, var, value);
 217        if (!strcmp(var, "diff.orderfile"))
 218                return git_config_pathname(&diff_order_file_cfg, var, value);
 219
 220        if (!strcmp(var, "diff.ignoresubmodules"))
 221                handle_ignore_submodules_arg(&default_diff_options, value);
 222
 223        if (!strcmp(var, "diff.submodule")) {
 224                if (parse_submodule_params(&default_diff_options, value))
 225                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 226                                value);
 227                return 0;
 228        }
 229
 230        if (!strcmp(var, "diff.algorithm")) {
 231                diff_algorithm = parse_algorithm_value(value);
 232                if (diff_algorithm < 0)
 233                        return -1;
 234                return 0;
 235        }
 236
 237        if (git_color_config(var, value, cb) < 0)
 238                return -1;
 239
 240        return git_diff_basic_config(var, value, cb);
 241}
 242
 243int git_diff_basic_config(const char *var, const char *value, void *cb)
 244{
 245        const char *name;
 246
 247        if (!strcmp(var, "diff.renamelimit")) {
 248                diff_rename_limit_default = git_config_int(var, value);
 249                return 0;
 250        }
 251
 252        if (userdiff_config(var, value) < 0)
 253                return -1;
 254
 255        if (skip_prefix(var, "diff.color.", &name) ||
 256            skip_prefix(var, "color.diff.", &name)) {
 257                int slot = parse_diff_color_slot(name);
 258                if (slot < 0)
 259                        return 0;
 260                if (!value)
 261                        return config_error_nonbool(var);
 262                return color_parse(value, diff_colors[slot]);
 263        }
 264
 265        /* like GNU diff's --suppress-blank-empty option  */
 266        if (!strcmp(var, "diff.suppressblankempty") ||
 267                        /* for backwards compatibility */
 268                        !strcmp(var, "diff.suppress-blank-empty")) {
 269                diff_suppress_blank_empty = git_config_bool(var, value);
 270                return 0;
 271        }
 272
 273        if (!strcmp(var, "diff.dirstat")) {
 274                struct strbuf errmsg = STRBUF_INIT;
 275                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 276                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 277                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 278                                errmsg.buf);
 279                strbuf_release(&errmsg);
 280                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 281                return 0;
 282        }
 283
 284        if (starts_with(var, "submodule."))
 285                return parse_submodule_config_option(var, value);
 286
 287        return git_default_config(var, value, cb);
 288}
 289
 290static char *quote_two(const char *one, const char *two)
 291{
 292        int need_one = quote_c_style(one, NULL, NULL, 1);
 293        int need_two = quote_c_style(two, NULL, NULL, 1);
 294        struct strbuf res = STRBUF_INIT;
 295
 296        if (need_one + need_two) {
 297                strbuf_addch(&res, '"');
 298                quote_c_style(one, &res, NULL, 1);
 299                quote_c_style(two, &res, NULL, 1);
 300                strbuf_addch(&res, '"');
 301        } else {
 302                strbuf_addstr(&res, one);
 303                strbuf_addstr(&res, two);
 304        }
 305        return strbuf_detach(&res, NULL);
 306}
 307
 308static const char *external_diff(void)
 309{
 310        static const char *external_diff_cmd = NULL;
 311        static int done_preparing = 0;
 312
 313        if (done_preparing)
 314                return external_diff_cmd;
 315        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 316        if (!external_diff_cmd)
 317                external_diff_cmd = external_diff_cmd_cfg;
 318        done_preparing = 1;
 319        return external_diff_cmd;
 320}
 321
 322/*
 323 * Keep track of files used for diffing. Sometimes such an entry
 324 * refers to a temporary file, sometimes to an existing file, and
 325 * sometimes to "/dev/null".
 326 */
 327static struct diff_tempfile {
 328        /*
 329         * filename external diff should read from, or NULL if this
 330         * entry is currently not in use:
 331         */
 332        const char *name;
 333
 334        char hex[GIT_SHA1_HEXSZ + 1];
 335        char mode[10];
 336
 337        /*
 338         * If this diff_tempfile instance refers to a temporary file,
 339         * this tempfile object is used to manage its lifetime.
 340         */
 341        struct tempfile tempfile;
 342} diff_temp[2];
 343
 344typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 345
 346struct emit_callback {
 347        int color_diff;
 348        unsigned ws_rule;
 349        int blank_at_eof_in_preimage;
 350        int blank_at_eof_in_postimage;
 351        int lno_in_preimage;
 352        int lno_in_postimage;
 353        sane_truncate_fn truncate;
 354        const char **label_path;
 355        struct diff_words_data *diff_words;
 356        struct diff_options *opt;
 357        struct strbuf *header;
 358};
 359
 360static int count_lines(const char *data, int size)
 361{
 362        int count, ch, completely_empty = 1, nl_just_seen = 0;
 363        count = 0;
 364        while (0 < size--) {
 365                ch = *data++;
 366                if (ch == '\n') {
 367                        count++;
 368                        nl_just_seen = 1;
 369                        completely_empty = 0;
 370                }
 371                else {
 372                        nl_just_seen = 0;
 373                        completely_empty = 0;
 374                }
 375        }
 376        if (completely_empty)
 377                return 0;
 378        if (!nl_just_seen)
 379                count++; /* no trailing newline */
 380        return count;
 381}
 382
 383static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 384{
 385        if (!DIFF_FILE_VALID(one)) {
 386                mf->ptr = (char *)""; /* does not matter */
 387                mf->size = 0;
 388                return 0;
 389        }
 390        else if (diff_populate_filespec(one, 0))
 391                return -1;
 392
 393        mf->ptr = one->data;
 394        mf->size = one->size;
 395        return 0;
 396}
 397
 398/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 399static unsigned long diff_filespec_size(struct diff_filespec *one)
 400{
 401        if (!DIFF_FILE_VALID(one))
 402                return 0;
 403        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 404        return one->size;
 405}
 406
 407static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 408{
 409        char *ptr = mf->ptr;
 410        long size = mf->size;
 411        int cnt = 0;
 412
 413        if (!size)
 414                return cnt;
 415        ptr += size - 1; /* pointing at the very end */
 416        if (*ptr != '\n')
 417                ; /* incomplete line */
 418        else
 419                ptr--; /* skip the last LF */
 420        while (mf->ptr < ptr) {
 421                char *prev_eol;
 422                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 423                        if (*prev_eol == '\n')
 424                                break;
 425                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 426                        break;
 427                cnt++;
 428                ptr = prev_eol - 1;
 429        }
 430        return cnt;
 431}
 432
 433static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 434                               struct emit_callback *ecbdata)
 435{
 436        int l1, l2, at;
 437        unsigned ws_rule = ecbdata->ws_rule;
 438        l1 = count_trailing_blank(mf1, ws_rule);
 439        l2 = count_trailing_blank(mf2, ws_rule);
 440        if (l2 <= l1) {
 441                ecbdata->blank_at_eof_in_preimage = 0;
 442                ecbdata->blank_at_eof_in_postimage = 0;
 443                return;
 444        }
 445        at = count_lines(mf1->ptr, mf1->size);
 446        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 447
 448        at = count_lines(mf2->ptr, mf2->size);
 449        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 450}
 451
 452static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 453                        int first, const char *line, int len)
 454{
 455        int has_trailing_newline, has_trailing_carriage_return;
 456        int nofirst;
 457        FILE *file = o->file;
 458
 459        fputs(diff_line_prefix(o), file);
 460
 461        if (len == 0) {
 462                has_trailing_newline = (first == '\n');
 463                has_trailing_carriage_return = (!has_trailing_newline &&
 464                                                (first == '\r'));
 465                nofirst = has_trailing_newline || has_trailing_carriage_return;
 466        } else {
 467                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 468                if (has_trailing_newline)
 469                        len--;
 470                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 471                if (has_trailing_carriage_return)
 472                        len--;
 473                nofirst = 0;
 474        }
 475
 476        if (len || !nofirst) {
 477                fputs(set, file);
 478                if (!nofirst)
 479                        fputc(first, file);
 480                fwrite(line, len, 1, file);
 481                fputs(reset, file);
 482        }
 483        if (has_trailing_carriage_return)
 484                fputc('\r', file);
 485        if (has_trailing_newline)
 486                fputc('\n', file);
 487}
 488
 489static void emit_line(struct diff_options *o, const char *set, const char *reset,
 490                      const char *line, int len)
 491{
 492        emit_line_0(o, set, reset, line[0], line+1, len-1);
 493}
 494
 495static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 496{
 497        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 498              ecbdata->blank_at_eof_in_preimage &&
 499              ecbdata->blank_at_eof_in_postimage &&
 500              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 501              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 502                return 0;
 503        return ws_blank_line(line, len, ecbdata->ws_rule);
 504}
 505
 506static void emit_line_checked(const char *reset,
 507                              struct emit_callback *ecbdata,
 508                              const char *line, int len,
 509                              enum color_diff color,
 510                              unsigned ws_error_highlight,
 511                              char sign)
 512{
 513        const char *set = diff_get_color(ecbdata->color_diff, color);
 514        const char *ws = NULL;
 515
 516        if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 517                ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 518                if (!*ws)
 519                        ws = NULL;
 520        }
 521
 522        if (!ws)
 523                emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 524        else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 525                /* Blank line at EOF - paint '+' as well */
 526                emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 527        else {
 528                /* Emit just the prefix, then the rest. */
 529                emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 530                ws_check_emit(line, len, ecbdata->ws_rule,
 531                              ecbdata->opt->file, set, reset, ws);
 532        }
 533}
 534
 535static void emit_add_line(const char *reset,
 536                          struct emit_callback *ecbdata,
 537                          const char *line, int len)
 538{
 539        emit_line_checked(reset, ecbdata, line, len,
 540                          DIFF_FILE_NEW, WSEH_NEW, '+');
 541}
 542
 543static void emit_del_line(const char *reset,
 544                          struct emit_callback *ecbdata,
 545                          const char *line, int len)
 546{
 547        emit_line_checked(reset, ecbdata, line, len,
 548                          DIFF_FILE_OLD, WSEH_OLD, '-');
 549}
 550
 551static void emit_context_line(const char *reset,
 552                              struct emit_callback *ecbdata,
 553                              const char *line, int len)
 554{
 555        emit_line_checked(reset, ecbdata, line, len,
 556                          DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 557}
 558
 559static void emit_hunk_header(struct emit_callback *ecbdata,
 560                             const char *line, int len)
 561{
 562        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 563        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 564        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 565        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 566        static const char atat[2] = { '@', '@' };
 567        const char *cp, *ep;
 568        struct strbuf msgbuf = STRBUF_INIT;
 569        int org_len = len;
 570        int i = 1;
 571
 572        /*
 573         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 574         * it always is at least 10 bytes long.
 575         */
 576        if (len < 10 ||
 577            memcmp(line, atat, 2) ||
 578            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 579                emit_line(ecbdata->opt, context, reset, line, len);
 580                return;
 581        }
 582        ep += 2; /* skip over @@ */
 583
 584        /* The hunk header in fraginfo color */
 585        strbuf_addstr(&msgbuf, frag);
 586        strbuf_add(&msgbuf, line, ep - line);
 587        strbuf_addstr(&msgbuf, reset);
 588
 589        /*
 590         * trailing "\r\n"
 591         */
 592        for ( ; i < 3; i++)
 593                if (line[len - i] == '\r' || line[len - i] == '\n')
 594                        len--;
 595
 596        /* blank before the func header */
 597        for (cp = ep; ep - line < len; ep++)
 598                if (*ep != ' ' && *ep != '\t')
 599                        break;
 600        if (ep != cp) {
 601                strbuf_addstr(&msgbuf, context);
 602                strbuf_add(&msgbuf, cp, ep - cp);
 603                strbuf_addstr(&msgbuf, reset);
 604        }
 605
 606        if (ep < line + len) {
 607                strbuf_addstr(&msgbuf, func);
 608                strbuf_add(&msgbuf, ep, line + len - ep);
 609                strbuf_addstr(&msgbuf, reset);
 610        }
 611
 612        strbuf_add(&msgbuf, line + len, org_len - len);
 613        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 614        strbuf_release(&msgbuf);
 615}
 616
 617static struct diff_tempfile *claim_diff_tempfile(void) {
 618        int i;
 619        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 620                if (!diff_temp[i].name)
 621                        return diff_temp + i;
 622        die("BUG: diff is failing to clean up its tempfiles");
 623}
 624
 625static void remove_tempfile(void)
 626{
 627        int i;
 628        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 629                if (is_tempfile_active(&diff_temp[i].tempfile))
 630                        delete_tempfile(&diff_temp[i].tempfile);
 631                diff_temp[i].name = NULL;
 632        }
 633}
 634
 635static void print_line_count(FILE *file, int count)
 636{
 637        switch (count) {
 638        case 0:
 639                fprintf(file, "0,0");
 640                break;
 641        case 1:
 642                fprintf(file, "1");
 643                break;
 644        default:
 645                fprintf(file, "1,%d", count);
 646                break;
 647        }
 648}
 649
 650static void emit_rewrite_lines(struct emit_callback *ecb,
 651                               int prefix, const char *data, int size)
 652{
 653        const char *endp = NULL;
 654        static const char *nneof = " No newline at end of file\n";
 655        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 656
 657        while (0 < size) {
 658                int len;
 659
 660                endp = memchr(data, '\n', size);
 661                len = endp ? (endp - data + 1) : size;
 662                if (prefix != '+') {
 663                        ecb->lno_in_preimage++;
 664                        emit_del_line(reset, ecb, data, len);
 665                } else {
 666                        ecb->lno_in_postimage++;
 667                        emit_add_line(reset, ecb, data, len);
 668                }
 669                size -= len;
 670                data += len;
 671        }
 672        if (!endp) {
 673                const char *context = diff_get_color(ecb->color_diff,
 674                                                     DIFF_CONTEXT);
 675                putc('\n', ecb->opt->file);
 676                emit_line_0(ecb->opt, context, reset, '\\',
 677                            nneof, strlen(nneof));
 678        }
 679}
 680
 681static void emit_rewrite_diff(const char *name_a,
 682                              const char *name_b,
 683                              struct diff_filespec *one,
 684                              struct diff_filespec *two,
 685                              struct userdiff_driver *textconv_one,
 686                              struct userdiff_driver *textconv_two,
 687                              struct diff_options *o)
 688{
 689        int lc_a, lc_b;
 690        const char *name_a_tab, *name_b_tab;
 691        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 692        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 693        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 694        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 695        const char *a_prefix, *b_prefix;
 696        char *data_one, *data_two;
 697        size_t size_one, size_two;
 698        struct emit_callback ecbdata;
 699        const char *line_prefix = diff_line_prefix(o);
 700
 701        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 702                a_prefix = o->b_prefix;
 703                b_prefix = o->a_prefix;
 704        } else {
 705                a_prefix = o->a_prefix;
 706                b_prefix = o->b_prefix;
 707        }
 708
 709        name_a += (*name_a == '/');
 710        name_b += (*name_b == '/');
 711        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 712        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 713
 714        strbuf_reset(&a_name);
 715        strbuf_reset(&b_name);
 716        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 717        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 718
 719        size_one = fill_textconv(textconv_one, one, &data_one);
 720        size_two = fill_textconv(textconv_two, two, &data_two);
 721
 722        memset(&ecbdata, 0, sizeof(ecbdata));
 723        ecbdata.color_diff = want_color(o->use_color);
 724        ecbdata.ws_rule = whitespace_rule(name_b);
 725        ecbdata.opt = o;
 726        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 727                mmfile_t mf1, mf2;
 728                mf1.ptr = (char *)data_one;
 729                mf2.ptr = (char *)data_two;
 730                mf1.size = size_one;
 731                mf2.size = size_two;
 732                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 733        }
 734        ecbdata.lno_in_preimage = 1;
 735        ecbdata.lno_in_postimage = 1;
 736
 737        lc_a = count_lines(data_one, size_one);
 738        lc_b = count_lines(data_two, size_two);
 739        fprintf(o->file,
 740                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 741                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 742                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 743                line_prefix, fraginfo);
 744        if (!o->irreversible_delete)
 745                print_line_count(o->file, lc_a);
 746        else
 747                fprintf(o->file, "?,?");
 748        fprintf(o->file, " +");
 749        print_line_count(o->file, lc_b);
 750        fprintf(o->file, " @@%s\n", reset);
 751        if (lc_a && !o->irreversible_delete)
 752                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 753        if (lc_b)
 754                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 755        if (textconv_one)
 756                free((char *)data_one);
 757        if (textconv_two)
 758                free((char *)data_two);
 759}
 760
 761struct diff_words_buffer {
 762        mmfile_t text;
 763        long alloc;
 764        struct diff_words_orig {
 765                const char *begin, *end;
 766        } *orig;
 767        int orig_nr, orig_alloc;
 768};
 769
 770static void diff_words_append(char *line, unsigned long len,
 771                struct diff_words_buffer *buffer)
 772{
 773        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 774        line++;
 775        len--;
 776        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 777        buffer->text.size += len;
 778        buffer->text.ptr[buffer->text.size] = '\0';
 779}
 780
 781struct diff_words_style_elem {
 782        const char *prefix;
 783        const char *suffix;
 784        const char *color; /* NULL; filled in by the setup code if
 785                            * color is enabled */
 786};
 787
 788struct diff_words_style {
 789        enum diff_words_type type;
 790        struct diff_words_style_elem new, old, ctx;
 791        const char *newline;
 792};
 793
 794static struct diff_words_style diff_words_styles[] = {
 795        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 796        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 797        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 798};
 799
 800struct diff_words_data {
 801        struct diff_words_buffer minus, plus;
 802        const char *current_plus;
 803        int last_minus;
 804        struct diff_options *opt;
 805        regex_t *word_regex;
 806        enum diff_words_type type;
 807        struct diff_words_style *style;
 808};
 809
 810static int fn_out_diff_words_write_helper(FILE *fp,
 811                                          struct diff_words_style_elem *st_el,
 812                                          const char *newline,
 813                                          size_t count, const char *buf,
 814                                          const char *line_prefix)
 815{
 816        int print = 0;
 817
 818        while (count) {
 819                char *p = memchr(buf, '\n', count);
 820                if (print)
 821                        fputs(line_prefix, fp);
 822                if (p != buf) {
 823                        if (st_el->color && fputs(st_el->color, fp) < 0)
 824                                return -1;
 825                        if (fputs(st_el->prefix, fp) < 0 ||
 826                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 827                            fputs(st_el->suffix, fp) < 0)
 828                                return -1;
 829                        if (st_el->color && *st_el->color
 830                            && fputs(GIT_COLOR_RESET, fp) < 0)
 831                                return -1;
 832                }
 833                if (!p)
 834                        return 0;
 835                if (fputs(newline, fp) < 0)
 836                        return -1;
 837                count -= p + 1 - buf;
 838                buf = p + 1;
 839                print = 1;
 840        }
 841        return 0;
 842}
 843
 844/*
 845 * '--color-words' algorithm can be described as:
 846 *
 847 *   1. collect a the minus/plus lines of a diff hunk, divided into
 848 *      minus-lines and plus-lines;
 849 *
 850 *   2. break both minus-lines and plus-lines into words and
 851 *      place them into two mmfile_t with one word for each line;
 852 *
 853 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 854 *
 855 * And for the common parts of the both file, we output the plus side text.
 856 * diff_words->current_plus is used to trace the current position of the plus file
 857 * which printed. diff_words->last_minus is used to trace the last minus word
 858 * printed.
 859 *
 860 * For '--graph' to work with '--color-words', we need to output the graph prefix
 861 * on each line of color words output. Generally, there are two conditions on
 862 * which we should output the prefix.
 863 *
 864 *   1. diff_words->last_minus == 0 &&
 865 *      diff_words->current_plus == diff_words->plus.text.ptr
 866 *
 867 *      that is: the plus text must start as a new line, and if there is no minus
 868 *      word printed, a graph prefix must be printed.
 869 *
 870 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 871 *      *(diff_words->current_plus - 1) == '\n'
 872 *
 873 *      that is: a graph prefix must be printed following a '\n'
 874 */
 875static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 876{
 877        if ((diff_words->last_minus == 0 &&
 878                diff_words->current_plus == diff_words->plus.text.ptr) ||
 879                (diff_words->current_plus > diff_words->plus.text.ptr &&
 880                *(diff_words->current_plus - 1) == '\n')) {
 881                return 1;
 882        } else {
 883                return 0;
 884        }
 885}
 886
 887static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 888{
 889        struct diff_words_data *diff_words = priv;
 890        struct diff_words_style *style = diff_words->style;
 891        int minus_first, minus_len, plus_first, plus_len;
 892        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 893        struct diff_options *opt = diff_words->opt;
 894        const char *line_prefix;
 895
 896        if (line[0] != '@' || parse_hunk_header(line, len,
 897                        &minus_first, &minus_len, &plus_first, &plus_len))
 898                return;
 899
 900        assert(opt);
 901        line_prefix = diff_line_prefix(opt);
 902
 903        /* POSIX requires that first be decremented by one if len == 0... */
 904        if (minus_len) {
 905                minus_begin = diff_words->minus.orig[minus_first].begin;
 906                minus_end =
 907                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 908        } else
 909                minus_begin = minus_end =
 910                        diff_words->minus.orig[minus_first].end;
 911
 912        if (plus_len) {
 913                plus_begin = diff_words->plus.orig[plus_first].begin;
 914                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 915        } else
 916                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 917
 918        if (color_words_output_graph_prefix(diff_words)) {
 919                fputs(line_prefix, diff_words->opt->file);
 920        }
 921        if (diff_words->current_plus != plus_begin) {
 922                fn_out_diff_words_write_helper(diff_words->opt->file,
 923                                &style->ctx, style->newline,
 924                                plus_begin - diff_words->current_plus,
 925                                diff_words->current_plus, line_prefix);
 926                if (*(plus_begin - 1) == '\n')
 927                        fputs(line_prefix, diff_words->opt->file);
 928        }
 929        if (minus_begin != minus_end) {
 930                fn_out_diff_words_write_helper(diff_words->opt->file,
 931                                &style->old, style->newline,
 932                                minus_end - minus_begin, minus_begin,
 933                                line_prefix);
 934        }
 935        if (plus_begin != plus_end) {
 936                fn_out_diff_words_write_helper(diff_words->opt->file,
 937                                &style->new, style->newline,
 938                                plus_end - plus_begin, plus_begin,
 939                                line_prefix);
 940        }
 941
 942        diff_words->current_plus = plus_end;
 943        diff_words->last_minus = minus_first;
 944}
 945
 946/* This function starts looking at *begin, and returns 0 iff a word was found. */
 947static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 948                int *begin, int *end)
 949{
 950        if (word_regex && *begin < buffer->size) {
 951                regmatch_t match[1];
 952                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 953                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 954                                        '\n', match[0].rm_eo - match[0].rm_so);
 955                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 956                        *begin += match[0].rm_so;
 957                        return *begin >= *end;
 958                }
 959                return -1;
 960        }
 961
 962        /* find the next word */
 963        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 964                (*begin)++;
 965        if (*begin >= buffer->size)
 966                return -1;
 967
 968        /* find the end of the word */
 969        *end = *begin + 1;
 970        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 971                (*end)++;
 972
 973        return 0;
 974}
 975
 976/*
 977 * This function splits the words in buffer->text, stores the list with
 978 * newline separator into out, and saves the offsets of the original words
 979 * in buffer->orig.
 980 */
 981static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 982                regex_t *word_regex)
 983{
 984        int i, j;
 985        long alloc = 0;
 986
 987        out->size = 0;
 988        out->ptr = NULL;
 989
 990        /* fake an empty "0th" word */
 991        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 992        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 993        buffer->orig_nr = 1;
 994
 995        for (i = 0; i < buffer->text.size; i++) {
 996                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 997                        return;
 998
 999                /* store original boundaries */
1000                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1001                                buffer->orig_alloc);
1002                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1003                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1004                buffer->orig_nr++;
1005
1006                /* store one word */
1007                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1008                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1009                out->ptr[out->size + j - i] = '\n';
1010                out->size += j - i + 1;
1011
1012                i = j - 1;
1013        }
1014}
1015
1016/* this executes the word diff on the accumulated buffers */
1017static void diff_words_show(struct diff_words_data *diff_words)
1018{
1019        xpparam_t xpp;
1020        xdemitconf_t xecfg;
1021        mmfile_t minus, plus;
1022        struct diff_words_style *style = diff_words->style;
1023
1024        struct diff_options *opt = diff_words->opt;
1025        const char *line_prefix;
1026
1027        assert(opt);
1028        line_prefix = diff_line_prefix(opt);
1029
1030        /* special case: only removal */
1031        if (!diff_words->plus.text.size) {
1032                fputs(line_prefix, diff_words->opt->file);
1033                fn_out_diff_words_write_helper(diff_words->opt->file,
1034                        &style->old, style->newline,
1035                        diff_words->minus.text.size,
1036                        diff_words->minus.text.ptr, line_prefix);
1037                diff_words->minus.text.size = 0;
1038                return;
1039        }
1040
1041        diff_words->current_plus = diff_words->plus.text.ptr;
1042        diff_words->last_minus = 0;
1043
1044        memset(&xpp, 0, sizeof(xpp));
1045        memset(&xecfg, 0, sizeof(xecfg));
1046        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1047        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1048        xpp.flags = 0;
1049        /* as only the hunk header will be parsed, we need a 0-context */
1050        xecfg.ctxlen = 0;
1051        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1052                          &xpp, &xecfg))
1053                die("unable to generate word diff");
1054        free(minus.ptr);
1055        free(plus.ptr);
1056        if (diff_words->current_plus != diff_words->plus.text.ptr +
1057                        diff_words->plus.text.size) {
1058                if (color_words_output_graph_prefix(diff_words))
1059                        fputs(line_prefix, diff_words->opt->file);
1060                fn_out_diff_words_write_helper(diff_words->opt->file,
1061                        &style->ctx, style->newline,
1062                        diff_words->plus.text.ptr + diff_words->plus.text.size
1063                        - diff_words->current_plus, diff_words->current_plus,
1064                        line_prefix);
1065        }
1066        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1067}
1068
1069/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1070static void diff_words_flush(struct emit_callback *ecbdata)
1071{
1072        if (ecbdata->diff_words->minus.text.size ||
1073            ecbdata->diff_words->plus.text.size)
1074                diff_words_show(ecbdata->diff_words);
1075}
1076
1077static void diff_filespec_load_driver(struct diff_filespec *one)
1078{
1079        /* Use already-loaded driver */
1080        if (one->driver)
1081                return;
1082
1083        if (S_ISREG(one->mode))
1084                one->driver = userdiff_find_by_path(one->path);
1085
1086        /* Fallback to default settings */
1087        if (!one->driver)
1088                one->driver = userdiff_find_by_name("default");
1089}
1090
1091static const char *userdiff_word_regex(struct diff_filespec *one)
1092{
1093        diff_filespec_load_driver(one);
1094        return one->driver->word_regex;
1095}
1096
1097static void init_diff_words_data(struct emit_callback *ecbdata,
1098                                 struct diff_options *orig_opts,
1099                                 struct diff_filespec *one,
1100                                 struct diff_filespec *two)
1101{
1102        int i;
1103        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1104        memcpy(o, orig_opts, sizeof(struct diff_options));
1105
1106        ecbdata->diff_words =
1107                xcalloc(1, sizeof(struct diff_words_data));
1108        ecbdata->diff_words->type = o->word_diff;
1109        ecbdata->diff_words->opt = o;
1110        if (!o->word_regex)
1111                o->word_regex = userdiff_word_regex(one);
1112        if (!o->word_regex)
1113                o->word_regex = userdiff_word_regex(two);
1114        if (!o->word_regex)
1115                o->word_regex = diff_word_regex_cfg;
1116        if (o->word_regex) {
1117                ecbdata->diff_words->word_regex = (regex_t *)
1118                        xmalloc(sizeof(regex_t));
1119                if (regcomp(ecbdata->diff_words->word_regex,
1120                            o->word_regex,
1121                            REG_EXTENDED | REG_NEWLINE))
1122                        die ("Invalid regular expression: %s",
1123                             o->word_regex);
1124        }
1125        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1126                if (o->word_diff == diff_words_styles[i].type) {
1127                        ecbdata->diff_words->style =
1128                                &diff_words_styles[i];
1129                        break;
1130                }
1131        }
1132        if (want_color(o->use_color)) {
1133                struct diff_words_style *st = ecbdata->diff_words->style;
1134                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1135                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1136                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1137        }
1138}
1139
1140static void free_diff_words_data(struct emit_callback *ecbdata)
1141{
1142        if (ecbdata->diff_words) {
1143                diff_words_flush(ecbdata);
1144                free (ecbdata->diff_words->opt);
1145                free (ecbdata->diff_words->minus.text.ptr);
1146                free (ecbdata->diff_words->minus.orig);
1147                free (ecbdata->diff_words->plus.text.ptr);
1148                free (ecbdata->diff_words->plus.orig);
1149                if (ecbdata->diff_words->word_regex) {
1150                        regfree(ecbdata->diff_words->word_regex);
1151                        free(ecbdata->diff_words->word_regex);
1152                }
1153                free(ecbdata->diff_words);
1154                ecbdata->diff_words = NULL;
1155        }
1156}
1157
1158const char *diff_get_color(int diff_use_color, enum color_diff ix)
1159{
1160        if (want_color(diff_use_color))
1161                return diff_colors[ix];
1162        return "";
1163}
1164
1165const char *diff_line_prefix(struct diff_options *opt)
1166{
1167        struct strbuf *msgbuf;
1168        if (!opt->output_prefix)
1169                return "";
1170
1171        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1172        return msgbuf->buf;
1173}
1174
1175static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1176{
1177        const char *cp;
1178        unsigned long allot;
1179        size_t l = len;
1180
1181        if (ecb->truncate)
1182                return ecb->truncate(line, len);
1183        cp = line;
1184        allot = l;
1185        while (0 < l) {
1186                (void) utf8_width(&cp, &l);
1187                if (!cp)
1188                        break; /* truncated in the middle? */
1189        }
1190        return allot - l;
1191}
1192
1193static void find_lno(const char *line, struct emit_callback *ecbdata)
1194{
1195        const char *p;
1196        ecbdata->lno_in_preimage = 0;
1197        ecbdata->lno_in_postimage = 0;
1198        p = strchr(line, '-');
1199        if (!p)
1200                return; /* cannot happen */
1201        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1202        p = strchr(p, '+');
1203        if (!p)
1204                return; /* cannot happen */
1205        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1206}
1207
1208static void fn_out_consume(void *priv, char *line, unsigned long len)
1209{
1210        struct emit_callback *ecbdata = priv;
1211        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1212        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1213        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1214        struct diff_options *o = ecbdata->opt;
1215        const char *line_prefix = diff_line_prefix(o);
1216
1217        o->found_changes = 1;
1218
1219        if (ecbdata->header) {
1220                fprintf(o->file, "%s", ecbdata->header->buf);
1221                strbuf_reset(ecbdata->header);
1222                ecbdata->header = NULL;
1223        }
1224
1225        if (ecbdata->label_path[0]) {
1226                const char *name_a_tab, *name_b_tab;
1227
1228                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1229                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1230
1231                fprintf(o->file, "%s%s--- %s%s%s\n",
1232                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1233                fprintf(o->file, "%s%s+++ %s%s%s\n",
1234                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1235                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1236        }
1237
1238        if (diff_suppress_blank_empty
1239            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1240                line[0] = '\n';
1241                len = 1;
1242        }
1243
1244        if (line[0] == '@') {
1245                if (ecbdata->diff_words)
1246                        diff_words_flush(ecbdata);
1247                len = sane_truncate_line(ecbdata, line, len);
1248                find_lno(line, ecbdata);
1249                emit_hunk_header(ecbdata, line, len);
1250                if (line[len-1] != '\n')
1251                        putc('\n', o->file);
1252                return;
1253        }
1254
1255        if (ecbdata->diff_words) {
1256                if (line[0] == '-') {
1257                        diff_words_append(line, len,
1258                                          &ecbdata->diff_words->minus);
1259                        return;
1260                } else if (line[0] == '+') {
1261                        diff_words_append(line, len,
1262                                          &ecbdata->diff_words->plus);
1263                        return;
1264                } else if (starts_with(line, "\\ ")) {
1265                        /*
1266                         * Eat the "no newline at eof" marker as if we
1267                         * saw a "+" or "-" line with nothing on it,
1268                         * and return without diff_words_flush() to
1269                         * defer processing. If this is the end of
1270                         * preimage, more "+" lines may come after it.
1271                         */
1272                        return;
1273                }
1274                diff_words_flush(ecbdata);
1275                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1276                        emit_line(o, context, reset, line, len);
1277                        fputs("~\n", o->file);
1278                } else {
1279                        /*
1280                         * Skip the prefix character, if any.  With
1281                         * diff_suppress_blank_empty, there may be
1282                         * none.
1283                         */
1284                        if (line[0] != '\n') {
1285                              line++;
1286                              len--;
1287                        }
1288                        emit_line(o, context, reset, line, len);
1289                }
1290                return;
1291        }
1292
1293        switch (line[0]) {
1294        case '+':
1295                ecbdata->lno_in_postimage++;
1296                emit_add_line(reset, ecbdata, line + 1, len - 1);
1297                break;
1298        case '-':
1299                ecbdata->lno_in_preimage++;
1300                emit_del_line(reset, ecbdata, line + 1, len - 1);
1301                break;
1302        case ' ':
1303                ecbdata->lno_in_postimage++;
1304                ecbdata->lno_in_preimage++;
1305                emit_context_line(reset, ecbdata, line + 1, len - 1);
1306                break;
1307        default:
1308                /* incomplete line at the end */
1309                ecbdata->lno_in_preimage++;
1310                emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1311                          reset, line, len);
1312                break;
1313        }
1314}
1315
1316static char *pprint_rename(const char *a, const char *b)
1317{
1318        const char *old = a;
1319        const char *new = b;
1320        struct strbuf name = STRBUF_INIT;
1321        int pfx_length, sfx_length;
1322        int pfx_adjust_for_slash;
1323        int len_a = strlen(a);
1324        int len_b = strlen(b);
1325        int a_midlen, b_midlen;
1326        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1327        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1328
1329        if (qlen_a || qlen_b) {
1330                quote_c_style(a, &name, NULL, 0);
1331                strbuf_addstr(&name, " => ");
1332                quote_c_style(b, &name, NULL, 0);
1333                return strbuf_detach(&name, NULL);
1334        }
1335
1336        /* Find common prefix */
1337        pfx_length = 0;
1338        while (*old && *new && *old == *new) {
1339                if (*old == '/')
1340                        pfx_length = old - a + 1;
1341                old++;
1342                new++;
1343        }
1344
1345        /* Find common suffix */
1346        old = a + len_a;
1347        new = b + len_b;
1348        sfx_length = 0;
1349        /*
1350         * If there is a common prefix, it must end in a slash.  In
1351         * that case we let this loop run 1 into the prefix to see the
1352         * same slash.
1353         *
1354         * If there is no common prefix, we cannot do this as it would
1355         * underrun the input strings.
1356         */
1357        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1358        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1359               b + pfx_length - pfx_adjust_for_slash <= new &&
1360               *old == *new) {
1361                if (*old == '/')
1362                        sfx_length = len_a - (old - a);
1363                old--;
1364                new--;
1365        }
1366
1367        /*
1368         * pfx{mid-a => mid-b}sfx
1369         * {pfx-a => pfx-b}sfx
1370         * pfx{sfx-a => sfx-b}
1371         * name-a => name-b
1372         */
1373        a_midlen = len_a - pfx_length - sfx_length;
1374        b_midlen = len_b - pfx_length - sfx_length;
1375        if (a_midlen < 0)
1376                a_midlen = 0;
1377        if (b_midlen < 0)
1378                b_midlen = 0;
1379
1380        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1381        if (pfx_length + sfx_length) {
1382                strbuf_add(&name, a, pfx_length);
1383                strbuf_addch(&name, '{');
1384        }
1385        strbuf_add(&name, a + pfx_length, a_midlen);
1386        strbuf_addstr(&name, " => ");
1387        strbuf_add(&name, b + pfx_length, b_midlen);
1388        if (pfx_length + sfx_length) {
1389                strbuf_addch(&name, '}');
1390                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1391        }
1392        return strbuf_detach(&name, NULL);
1393}
1394
1395struct diffstat_t {
1396        int nr;
1397        int alloc;
1398        struct diffstat_file {
1399                char *from_name;
1400                char *name;
1401                char *print_name;
1402                unsigned is_unmerged:1;
1403                unsigned is_binary:1;
1404                unsigned is_renamed:1;
1405                unsigned is_interesting:1;
1406                uintmax_t added, deleted;
1407        } **files;
1408};
1409
1410static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1411                                          const char *name_a,
1412                                          const char *name_b)
1413{
1414        struct diffstat_file *x;
1415        x = xcalloc(1, sizeof(*x));
1416        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1417        diffstat->files[diffstat->nr++] = x;
1418        if (name_b) {
1419                x->from_name = xstrdup(name_a);
1420                x->name = xstrdup(name_b);
1421                x->is_renamed = 1;
1422        }
1423        else {
1424                x->from_name = NULL;
1425                x->name = xstrdup(name_a);
1426        }
1427        return x;
1428}
1429
1430static void diffstat_consume(void *priv, char *line, unsigned long len)
1431{
1432        struct diffstat_t *diffstat = priv;
1433        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1434
1435        if (line[0] == '+')
1436                x->added++;
1437        else if (line[0] == '-')
1438                x->deleted++;
1439}
1440
1441const char mime_boundary_leader[] = "------------";
1442
1443static int scale_linear(int it, int width, int max_change)
1444{
1445        if (!it)
1446                return 0;
1447        /*
1448         * make sure that at least one '-' or '+' is printed if
1449         * there is any change to this path. The easiest way is to
1450         * scale linearly as if the alloted width is one column shorter
1451         * than it is, and then add 1 to the result.
1452         */
1453        return 1 + (it * (width - 1) / max_change);
1454}
1455
1456static void show_name(FILE *file,
1457                      const char *prefix, const char *name, int len)
1458{
1459        fprintf(file, " %s%-*s |", prefix, len, name);
1460}
1461
1462static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1463{
1464        if (cnt <= 0)
1465                return;
1466        fprintf(file, "%s", set);
1467        while (cnt--)
1468                putc(ch, file);
1469        fprintf(file, "%s", reset);
1470}
1471
1472static void fill_print_name(struct diffstat_file *file)
1473{
1474        char *pname;
1475
1476        if (file->print_name)
1477                return;
1478
1479        if (!file->is_renamed) {
1480                struct strbuf buf = STRBUF_INIT;
1481                if (quote_c_style(file->name, &buf, NULL, 0)) {
1482                        pname = strbuf_detach(&buf, NULL);
1483                } else {
1484                        pname = file->name;
1485                        strbuf_release(&buf);
1486                }
1487        } else {
1488                pname = pprint_rename(file->from_name, file->name);
1489        }
1490        file->print_name = pname;
1491}
1492
1493int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1494{
1495        struct strbuf sb = STRBUF_INIT;
1496        int ret;
1497
1498        if (!files) {
1499                assert(insertions == 0 && deletions == 0);
1500                return fprintf(fp, "%s\n", " 0 files changed");
1501        }
1502
1503        strbuf_addf(&sb,
1504                    (files == 1) ? " %d file changed" : " %d files changed",
1505                    files);
1506
1507        /*
1508         * For binary diff, the caller may want to print "x files
1509         * changed" with insertions == 0 && deletions == 0.
1510         *
1511         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1512         * is probably less confusing (i.e skip over "2 files changed
1513         * but nothing about added/removed lines? Is this a bug in Git?").
1514         */
1515        if (insertions || deletions == 0) {
1516                strbuf_addf(&sb,
1517                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1518                            insertions);
1519        }
1520
1521        if (deletions || insertions == 0) {
1522                strbuf_addf(&sb,
1523                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1524                            deletions);
1525        }
1526        strbuf_addch(&sb, '\n');
1527        ret = fputs(sb.buf, fp);
1528        strbuf_release(&sb);
1529        return ret;
1530}
1531
1532static void show_stats(struct diffstat_t *data, struct diff_options *options)
1533{
1534        int i, len, add, del, adds = 0, dels = 0;
1535        uintmax_t max_change = 0, max_len = 0;
1536        int total_files = data->nr, count;
1537        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1538        const char *reset, *add_c, *del_c;
1539        const char *line_prefix = "";
1540        int extra_shown = 0;
1541
1542        if (data->nr == 0)
1543                return;
1544
1545        line_prefix = diff_line_prefix(options);
1546        count = options->stat_count ? options->stat_count : data->nr;
1547
1548        reset = diff_get_color_opt(options, DIFF_RESET);
1549        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1550        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1551
1552        /*
1553         * Find the longest filename and max number of changes
1554         */
1555        for (i = 0; (i < count) && (i < data->nr); i++) {
1556                struct diffstat_file *file = data->files[i];
1557                uintmax_t change = file->added + file->deleted;
1558
1559                if (!file->is_interesting && (change == 0)) {
1560                        count++; /* not shown == room for one more */
1561                        continue;
1562                }
1563                fill_print_name(file);
1564                len = strlen(file->print_name);
1565                if (max_len < len)
1566                        max_len = len;
1567
1568                if (file->is_unmerged) {
1569                        /* "Unmerged" is 8 characters */
1570                        bin_width = bin_width < 8 ? 8 : bin_width;
1571                        continue;
1572                }
1573                if (file->is_binary) {
1574                        /* "Bin XXX -> YYY bytes" */
1575                        int w = 14 + decimal_width(file->added)
1576                                + decimal_width(file->deleted);
1577                        bin_width = bin_width < w ? w : bin_width;
1578                        /* Display change counts aligned with "Bin" */
1579                        number_width = 3;
1580                        continue;
1581                }
1582
1583                if (max_change < change)
1584                        max_change = change;
1585        }
1586        count = i; /* where we can stop scanning in data->files[] */
1587
1588        /*
1589         * We have width = stat_width or term_columns() columns total.
1590         * We want a maximum of min(max_len, stat_name_width) for the name part.
1591         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1592         * We also need 1 for " " and 4 + decimal_width(max_change)
1593         * for " | NNNN " and one the empty column at the end, altogether
1594         * 6 + decimal_width(max_change).
1595         *
1596         * If there's not enough space, we will use the smaller of
1597         * stat_name_width (if set) and 5/8*width for the filename,
1598         * and the rest for constant elements + graph part, but no more
1599         * than stat_graph_width for the graph part.
1600         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1601         * for the standard terminal size).
1602         *
1603         * In other words: stat_width limits the maximum width, and
1604         * stat_name_width fixes the maximum width of the filename,
1605         * and is also used to divide available columns if there
1606         * aren't enough.
1607         *
1608         * Binary files are displayed with "Bin XXX -> YYY bytes"
1609         * instead of the change count and graph. This part is treated
1610         * similarly to the graph part, except that it is not
1611         * "scaled". If total width is too small to accommodate the
1612         * guaranteed minimum width of the filename part and the
1613         * separators and this message, this message will "overflow"
1614         * making the line longer than the maximum width.
1615         */
1616
1617        if (options->stat_width == -1)
1618                width = term_columns() - options->output_prefix_length;
1619        else
1620                width = options->stat_width ? options->stat_width : 80;
1621        number_width = decimal_width(max_change) > number_width ?
1622                decimal_width(max_change) : number_width;
1623
1624        if (options->stat_graph_width == -1)
1625                options->stat_graph_width = diff_stat_graph_width;
1626
1627        /*
1628         * Guarantee 3/8*16==6 for the graph part
1629         * and 5/8*16==10 for the filename part
1630         */
1631        if (width < 16 + 6 + number_width)
1632                width = 16 + 6 + number_width;
1633
1634        /*
1635         * First assign sizes that are wanted, ignoring available width.
1636         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1637         * starting from "XXX" should fit in graph_width.
1638         */
1639        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1640        if (options->stat_graph_width &&
1641            options->stat_graph_width < graph_width)
1642                graph_width = options->stat_graph_width;
1643
1644        name_width = (options->stat_name_width > 0 &&
1645                      options->stat_name_width < max_len) ?
1646                options->stat_name_width : max_len;
1647
1648        /*
1649         * Adjust adjustable widths not to exceed maximum width
1650         */
1651        if (name_width + number_width + 6 + graph_width > width) {
1652                if (graph_width > width * 3/8 - number_width - 6) {
1653                        graph_width = width * 3/8 - number_width - 6;
1654                        if (graph_width < 6)
1655                                graph_width = 6;
1656                }
1657
1658                if (options->stat_graph_width &&
1659                    graph_width > options->stat_graph_width)
1660                        graph_width = options->stat_graph_width;
1661                if (name_width > width - number_width - 6 - graph_width)
1662                        name_width = width - number_width - 6 - graph_width;
1663                else
1664                        graph_width = width - number_width - 6 - name_width;
1665        }
1666
1667        /*
1668         * From here name_width is the width of the name area,
1669         * and graph_width is the width of the graph area.
1670         * max_change is used to scale graph properly.
1671         */
1672        for (i = 0; i < count; i++) {
1673                const char *prefix = "";
1674                struct diffstat_file *file = data->files[i];
1675                char *name = file->print_name;
1676                uintmax_t added = file->added;
1677                uintmax_t deleted = file->deleted;
1678                int name_len;
1679
1680                if (!file->is_interesting && (added + deleted == 0))
1681                        continue;
1682
1683                /*
1684                 * "scale" the filename
1685                 */
1686                len = name_width;
1687                name_len = strlen(name);
1688                if (name_width < name_len) {
1689                        char *slash;
1690                        prefix = "...";
1691                        len -= 3;
1692                        name += name_len - len;
1693                        slash = strchr(name, '/');
1694                        if (slash)
1695                                name = slash;
1696                }
1697
1698                if (file->is_binary) {
1699                        fprintf(options->file, "%s", line_prefix);
1700                        show_name(options->file, prefix, name, len);
1701                        fprintf(options->file, " %*s", number_width, "Bin");
1702                        if (!added && !deleted) {
1703                                putc('\n', options->file);
1704                                continue;
1705                        }
1706                        fprintf(options->file, " %s%"PRIuMAX"%s",
1707                                del_c, deleted, reset);
1708                        fprintf(options->file, " -> ");
1709                        fprintf(options->file, "%s%"PRIuMAX"%s",
1710                                add_c, added, reset);
1711                        fprintf(options->file, " bytes");
1712                        fprintf(options->file, "\n");
1713                        continue;
1714                }
1715                else if (file->is_unmerged) {
1716                        fprintf(options->file, "%s", line_prefix);
1717                        show_name(options->file, prefix, name, len);
1718                        fprintf(options->file, " Unmerged\n");
1719                        continue;
1720                }
1721
1722                /*
1723                 * scale the add/delete
1724                 */
1725                add = added;
1726                del = deleted;
1727
1728                if (graph_width <= max_change) {
1729                        int total = scale_linear(add + del, graph_width, max_change);
1730                        if (total < 2 && add && del)
1731                                /* width >= 2 due to the sanity check */
1732                                total = 2;
1733                        if (add < del) {
1734                                add = scale_linear(add, graph_width, max_change);
1735                                del = total - add;
1736                        } else {
1737                                del = scale_linear(del, graph_width, max_change);
1738                                add = total - del;
1739                        }
1740                }
1741                fprintf(options->file, "%s", line_prefix);
1742                show_name(options->file, prefix, name, len);
1743                fprintf(options->file, " %*"PRIuMAX"%s",
1744                        number_width, added + deleted,
1745                        added + deleted ? " " : "");
1746                show_graph(options->file, '+', add, add_c, reset);
1747                show_graph(options->file, '-', del, del_c, reset);
1748                fprintf(options->file, "\n");
1749        }
1750
1751        for (i = 0; i < data->nr; i++) {
1752                struct diffstat_file *file = data->files[i];
1753                uintmax_t added = file->added;
1754                uintmax_t deleted = file->deleted;
1755
1756                if (file->is_unmerged ||
1757                    (!file->is_interesting && (added + deleted == 0))) {
1758                        total_files--;
1759                        continue;
1760                }
1761
1762                if (!file->is_binary) {
1763                        adds += added;
1764                        dels += deleted;
1765                }
1766                if (i < count)
1767                        continue;
1768                if (!extra_shown)
1769                        fprintf(options->file, "%s ...\n", line_prefix);
1770                extra_shown = 1;
1771        }
1772        fprintf(options->file, "%s", line_prefix);
1773        print_stat_summary(options->file, total_files, adds, dels);
1774}
1775
1776static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1777{
1778        int i, adds = 0, dels = 0, total_files = data->nr;
1779
1780        if (data->nr == 0)
1781                return;
1782
1783        for (i = 0; i < data->nr; i++) {
1784                int added = data->files[i]->added;
1785                int deleted= data->files[i]->deleted;
1786
1787                if (data->files[i]->is_unmerged ||
1788                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1789                        total_files--;
1790                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1791                        adds += added;
1792                        dels += deleted;
1793                }
1794        }
1795        fprintf(options->file, "%s", diff_line_prefix(options));
1796        print_stat_summary(options->file, total_files, adds, dels);
1797}
1798
1799static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1800{
1801        int i;
1802
1803        if (data->nr == 0)
1804                return;
1805
1806        for (i = 0; i < data->nr; i++) {
1807                struct diffstat_file *file = data->files[i];
1808
1809                fprintf(options->file, "%s", diff_line_prefix(options));
1810
1811                if (file->is_binary)
1812                        fprintf(options->file, "-\t-\t");
1813                else
1814                        fprintf(options->file,
1815                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1816                                file->added, file->deleted);
1817                if (options->line_termination) {
1818                        fill_print_name(file);
1819                        if (!file->is_renamed)
1820                                write_name_quoted(file->name, options->file,
1821                                                  options->line_termination);
1822                        else {
1823                                fputs(file->print_name, options->file);
1824                                putc(options->line_termination, options->file);
1825                        }
1826                } else {
1827                        if (file->is_renamed) {
1828                                putc('\0', options->file);
1829                                write_name_quoted(file->from_name, options->file, '\0');
1830                        }
1831                        write_name_quoted(file->name, options->file, '\0');
1832                }
1833        }
1834}
1835
1836struct dirstat_file {
1837        const char *name;
1838        unsigned long changed;
1839};
1840
1841struct dirstat_dir {
1842        struct dirstat_file *files;
1843        int alloc, nr, permille, cumulative;
1844};
1845
1846static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1847                unsigned long changed, const char *base, int baselen)
1848{
1849        unsigned long this_dir = 0;
1850        unsigned int sources = 0;
1851        const char *line_prefix = diff_line_prefix(opt);
1852
1853        while (dir->nr) {
1854                struct dirstat_file *f = dir->files;
1855                int namelen = strlen(f->name);
1856                unsigned long this;
1857                char *slash;
1858
1859                if (namelen < baselen)
1860                        break;
1861                if (memcmp(f->name, base, baselen))
1862                        break;
1863                slash = strchr(f->name + baselen, '/');
1864                if (slash) {
1865                        int newbaselen = slash + 1 - f->name;
1866                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1867                        sources++;
1868                } else {
1869                        this = f->changed;
1870                        dir->files++;
1871                        dir->nr--;
1872                        sources += 2;
1873                }
1874                this_dir += this;
1875        }
1876
1877        /*
1878         * We don't report dirstat's for
1879         *  - the top level
1880         *  - or cases where everything came from a single directory
1881         *    under this directory (sources == 1).
1882         */
1883        if (baselen && sources != 1) {
1884                if (this_dir) {
1885                        int permille = this_dir * 1000 / changed;
1886                        if (permille >= dir->permille) {
1887                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1888                                        permille / 10, permille % 10, baselen, base);
1889                                if (!dir->cumulative)
1890                                        return 0;
1891                        }
1892                }
1893        }
1894        return this_dir;
1895}
1896
1897static int dirstat_compare(const void *_a, const void *_b)
1898{
1899        const struct dirstat_file *a = _a;
1900        const struct dirstat_file *b = _b;
1901        return strcmp(a->name, b->name);
1902}
1903
1904static void show_dirstat(struct diff_options *options)
1905{
1906        int i;
1907        unsigned long changed;
1908        struct dirstat_dir dir;
1909        struct diff_queue_struct *q = &diff_queued_diff;
1910
1911        dir.files = NULL;
1912        dir.alloc = 0;
1913        dir.nr = 0;
1914        dir.permille = options->dirstat_permille;
1915        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1916
1917        changed = 0;
1918        for (i = 0; i < q->nr; i++) {
1919                struct diff_filepair *p = q->queue[i];
1920                const char *name;
1921                unsigned long copied, added, damage;
1922                int content_changed;
1923
1924                name = p->two->path ? p->two->path : p->one->path;
1925
1926                if (p->one->oid_valid && p->two->oid_valid)
1927                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
1928                else
1929                        content_changed = 1;
1930
1931                if (!content_changed) {
1932                        /*
1933                         * The SHA1 has not changed, so pre-/post-content is
1934                         * identical. We can therefore skip looking at the
1935                         * file contents altogether.
1936                         */
1937                        damage = 0;
1938                        goto found_damage;
1939                }
1940
1941                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1942                        /*
1943                         * In --dirstat-by-file mode, we don't really need to
1944                         * look at the actual file contents at all.
1945                         * The fact that the SHA1 changed is enough for us to
1946                         * add this file to the list of results
1947                         * (with each file contributing equal damage).
1948                         */
1949                        damage = 1;
1950                        goto found_damage;
1951                }
1952
1953                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1954                        diff_populate_filespec(p->one, 0);
1955                        diff_populate_filespec(p->two, 0);
1956                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1957                                               &copied, &added);
1958                        diff_free_filespec_data(p->one);
1959                        diff_free_filespec_data(p->two);
1960                } else if (DIFF_FILE_VALID(p->one)) {
1961                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1962                        copied = added = 0;
1963                        diff_free_filespec_data(p->one);
1964                } else if (DIFF_FILE_VALID(p->two)) {
1965                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1966                        copied = 0;
1967                        added = p->two->size;
1968                        diff_free_filespec_data(p->two);
1969                } else
1970                        continue;
1971
1972                /*
1973                 * Original minus copied is the removed material,
1974                 * added is the new material.  They are both damages
1975                 * made to the preimage.
1976                 * If the resulting damage is zero, we know that
1977                 * diffcore_count_changes() considers the two entries to
1978                 * be identical, but since content_changed is true, we
1979                 * know that there must have been _some_ kind of change,
1980                 * so we force all entries to have damage > 0.
1981                 */
1982                damage = (p->one->size - copied) + added;
1983                if (!damage)
1984                        damage = 1;
1985
1986found_damage:
1987                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1988                dir.files[dir.nr].name = name;
1989                dir.files[dir.nr].changed = damage;
1990                changed += damage;
1991                dir.nr++;
1992        }
1993
1994        /* This can happen even with many files, if everything was renames */
1995        if (!changed)
1996                return;
1997
1998        /* Show all directories with more than x% of the changes */
1999        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2000        gather_dirstat(options, &dir, changed, "", 0);
2001}
2002
2003static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2004{
2005        int i;
2006        unsigned long changed;
2007        struct dirstat_dir dir;
2008
2009        if (data->nr == 0)
2010                return;
2011
2012        dir.files = NULL;
2013        dir.alloc = 0;
2014        dir.nr = 0;
2015        dir.permille = options->dirstat_permille;
2016        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2017
2018        changed = 0;
2019        for (i = 0; i < data->nr; i++) {
2020                struct diffstat_file *file = data->files[i];
2021                unsigned long damage = file->added + file->deleted;
2022                if (file->is_binary)
2023                        /*
2024                         * binary files counts bytes, not lines. Must find some
2025                         * way to normalize binary bytes vs. textual lines.
2026                         * The following heuristic assumes that there are 64
2027                         * bytes per "line".
2028                         * This is stupid and ugly, but very cheap...
2029                         */
2030                        damage = (damage + 63) / 64;
2031                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2032                dir.files[dir.nr].name = file->name;
2033                dir.files[dir.nr].changed = damage;
2034                changed += damage;
2035                dir.nr++;
2036        }
2037
2038        /* This can happen even with many files, if everything was renames */
2039        if (!changed)
2040                return;
2041
2042        /* Show all directories with more than x% of the changes */
2043        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2044        gather_dirstat(options, &dir, changed, "", 0);
2045}
2046
2047static void free_diffstat_info(struct diffstat_t *diffstat)
2048{
2049        int i;
2050        for (i = 0; i < diffstat->nr; i++) {
2051                struct diffstat_file *f = diffstat->files[i];
2052                if (f->name != f->print_name)
2053                        free(f->print_name);
2054                free(f->name);
2055                free(f->from_name);
2056                free(f);
2057        }
2058        free(diffstat->files);
2059}
2060
2061struct checkdiff_t {
2062        const char *filename;
2063        int lineno;
2064        int conflict_marker_size;
2065        struct diff_options *o;
2066        unsigned ws_rule;
2067        unsigned status;
2068};
2069
2070static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2071{
2072        char firstchar;
2073        int cnt;
2074
2075        if (len < marker_size + 1)
2076                return 0;
2077        firstchar = line[0];
2078        switch (firstchar) {
2079        case '=': case '>': case '<': case '|':
2080                break;
2081        default:
2082                return 0;
2083        }
2084        for (cnt = 1; cnt < marker_size; cnt++)
2085                if (line[cnt] != firstchar)
2086                        return 0;
2087        /* line[1] thru line[marker_size-1] are same as firstchar */
2088        if (len < marker_size + 1 || !isspace(line[marker_size]))
2089                return 0;
2090        return 1;
2091}
2092
2093static void checkdiff_consume(void *priv, char *line, unsigned long len)
2094{
2095        struct checkdiff_t *data = priv;
2096        int marker_size = data->conflict_marker_size;
2097        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2098        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2099        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2100        char *err;
2101        const char *line_prefix;
2102
2103        assert(data->o);
2104        line_prefix = diff_line_prefix(data->o);
2105
2106        if (line[0] == '+') {
2107                unsigned bad;
2108                data->lineno++;
2109                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2110                        data->status |= 1;
2111                        fprintf(data->o->file,
2112                                "%s%s:%d: leftover conflict marker\n",
2113                                line_prefix, data->filename, data->lineno);
2114                }
2115                bad = ws_check(line + 1, len - 1, data->ws_rule);
2116                if (!bad)
2117                        return;
2118                data->status |= bad;
2119                err = whitespace_error_string(bad);
2120                fprintf(data->o->file, "%s%s:%d: %s.\n",
2121                        line_prefix, data->filename, data->lineno, err);
2122                free(err);
2123                emit_line(data->o, set, reset, line, 1);
2124                ws_check_emit(line + 1, len - 1, data->ws_rule,
2125                              data->o->file, set, reset, ws);
2126        } else if (line[0] == ' ') {
2127                data->lineno++;
2128        } else if (line[0] == '@') {
2129                char *plus = strchr(line, '+');
2130                if (plus)
2131                        data->lineno = strtol(plus, NULL, 10) - 1;
2132                else
2133                        die("invalid diff");
2134        }
2135}
2136
2137static unsigned char *deflate_it(char *data,
2138                                 unsigned long size,
2139                                 unsigned long *result_size)
2140{
2141        int bound;
2142        unsigned char *deflated;
2143        git_zstream stream;
2144
2145        git_deflate_init(&stream, zlib_compression_level);
2146        bound = git_deflate_bound(&stream, size);
2147        deflated = xmalloc(bound);
2148        stream.next_out = deflated;
2149        stream.avail_out = bound;
2150
2151        stream.next_in = (unsigned char *)data;
2152        stream.avail_in = size;
2153        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2154                ; /* nothing */
2155        git_deflate_end(&stream);
2156        *result_size = stream.total_out;
2157        return deflated;
2158}
2159
2160static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2161                                  const char *prefix)
2162{
2163        void *cp;
2164        void *delta;
2165        void *deflated;
2166        void *data;
2167        unsigned long orig_size;
2168        unsigned long delta_size;
2169        unsigned long deflate_size;
2170        unsigned long data_size;
2171
2172        /* We could do deflated delta, or we could do just deflated two,
2173         * whichever is smaller.
2174         */
2175        delta = NULL;
2176        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2177        if (one->size && two->size) {
2178                delta = diff_delta(one->ptr, one->size,
2179                                   two->ptr, two->size,
2180                                   &delta_size, deflate_size);
2181                if (delta) {
2182                        void *to_free = delta;
2183                        orig_size = delta_size;
2184                        delta = deflate_it(delta, delta_size, &delta_size);
2185                        free(to_free);
2186                }
2187        }
2188
2189        if (delta && delta_size < deflate_size) {
2190                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2191                free(deflated);
2192                data = delta;
2193                data_size = delta_size;
2194        }
2195        else {
2196                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2197                free(delta);
2198                data = deflated;
2199                data_size = deflate_size;
2200        }
2201
2202        /* emit data encoded in base85 */
2203        cp = data;
2204        while (data_size) {
2205                int bytes = (52 < data_size) ? 52 : data_size;
2206                char line[70];
2207                data_size -= bytes;
2208                if (bytes <= 26)
2209                        line[0] = bytes + 'A' - 1;
2210                else
2211                        line[0] = bytes - 26 + 'a' - 1;
2212                encode_85(line + 1, cp, bytes);
2213                cp = (char *) cp + bytes;
2214                fprintf(file, "%s", prefix);
2215                fputs(line, file);
2216                fputc('\n', file);
2217        }
2218        fprintf(file, "%s\n", prefix);
2219        free(data);
2220}
2221
2222static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2223                             const char *prefix)
2224{
2225        fprintf(file, "%sGIT binary patch\n", prefix);
2226        emit_binary_diff_body(file, one, two, prefix);
2227        emit_binary_diff_body(file, two, one, prefix);
2228}
2229
2230int diff_filespec_is_binary(struct diff_filespec *one)
2231{
2232        if (one->is_binary == -1) {
2233                diff_filespec_load_driver(one);
2234                if (one->driver->binary != -1)
2235                        one->is_binary = one->driver->binary;
2236                else {
2237                        if (!one->data && DIFF_FILE_VALID(one))
2238                                diff_populate_filespec(one, CHECK_BINARY);
2239                        if (one->is_binary == -1 && one->data)
2240                                one->is_binary = buffer_is_binary(one->data,
2241                                                one->size);
2242                        if (one->is_binary == -1)
2243                                one->is_binary = 0;
2244                }
2245        }
2246        return one->is_binary;
2247}
2248
2249static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2250{
2251        diff_filespec_load_driver(one);
2252        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2253}
2254
2255void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2256{
2257        if (!options->a_prefix)
2258                options->a_prefix = a;
2259        if (!options->b_prefix)
2260                options->b_prefix = b;
2261}
2262
2263struct userdiff_driver *get_textconv(struct diff_filespec *one)
2264{
2265        if (!DIFF_FILE_VALID(one))
2266                return NULL;
2267
2268        diff_filespec_load_driver(one);
2269        return userdiff_get_textconv(one->driver);
2270}
2271
2272static void builtin_diff(const char *name_a,
2273                         const char *name_b,
2274                         struct diff_filespec *one,
2275                         struct diff_filespec *two,
2276                         const char *xfrm_msg,
2277                         int must_show_header,
2278                         struct diff_options *o,
2279                         int complete_rewrite)
2280{
2281        mmfile_t mf1, mf2;
2282        const char *lbl[2];
2283        char *a_one, *b_two;
2284        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2285        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2286        const char *a_prefix, *b_prefix;
2287        struct userdiff_driver *textconv_one = NULL;
2288        struct userdiff_driver *textconv_two = NULL;
2289        struct strbuf header = STRBUF_INIT;
2290        const char *line_prefix = diff_line_prefix(o);
2291
2292        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2293                        (!one->mode || S_ISGITLINK(one->mode)) &&
2294                        (!two->mode || S_ISGITLINK(two->mode))) {
2295                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2296                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2297                show_submodule_summary(o->file, one->path ? one->path : two->path,
2298                                line_prefix,
2299                                one->oid.hash, two->oid.hash,
2300                                two->dirty_submodule,
2301                                meta, del, add, reset);
2302                return;
2303        }
2304
2305        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2306                textconv_one = get_textconv(one);
2307                textconv_two = get_textconv(two);
2308        }
2309
2310        diff_set_mnemonic_prefix(o, "a/", "b/");
2311        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2312                a_prefix = o->b_prefix;
2313                b_prefix = o->a_prefix;
2314        } else {
2315                a_prefix = o->a_prefix;
2316                b_prefix = o->b_prefix;
2317        }
2318
2319        /* Never use a non-valid filename anywhere if at all possible */
2320        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2321        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2322
2323        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2324        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2325        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2326        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2327        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2328        if (lbl[0][0] == '/') {
2329                /* /dev/null */
2330                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2331                if (xfrm_msg)
2332                        strbuf_addstr(&header, xfrm_msg);
2333                must_show_header = 1;
2334        }
2335        else if (lbl[1][0] == '/') {
2336                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2337                if (xfrm_msg)
2338                        strbuf_addstr(&header, xfrm_msg);
2339                must_show_header = 1;
2340        }
2341        else {
2342                if (one->mode != two->mode) {
2343                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2344                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2345                        must_show_header = 1;
2346                }
2347                if (xfrm_msg)
2348                        strbuf_addstr(&header, xfrm_msg);
2349
2350                /*
2351                 * we do not run diff between different kind
2352                 * of objects.
2353                 */
2354                if ((one->mode ^ two->mode) & S_IFMT)
2355                        goto free_ab_and_return;
2356                if (complete_rewrite &&
2357                    (textconv_one || !diff_filespec_is_binary(one)) &&
2358                    (textconv_two || !diff_filespec_is_binary(two))) {
2359                        fprintf(o->file, "%s", header.buf);
2360                        strbuf_reset(&header);
2361                        emit_rewrite_diff(name_a, name_b, one, two,
2362                                                textconv_one, textconv_two, o);
2363                        o->found_changes = 1;
2364                        goto free_ab_and_return;
2365                }
2366        }
2367
2368        if (o->irreversible_delete && lbl[1][0] == '/') {
2369                fprintf(o->file, "%s", header.buf);
2370                strbuf_reset(&header);
2371                goto free_ab_and_return;
2372        } else if (!DIFF_OPT_TST(o, TEXT) &&
2373            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2374              (!textconv_two && diff_filespec_is_binary(two)) )) {
2375                if (!one->data && !two->data &&
2376                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2377                    !DIFF_OPT_TST(o, BINARY)) {
2378                        if (!oidcmp(&one->oid, &two->oid)) {
2379                                if (must_show_header)
2380                                        fprintf(o->file, "%s", header.buf);
2381                                goto free_ab_and_return;
2382                        }
2383                        fprintf(o->file, "%s", header.buf);
2384                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2385                                line_prefix, lbl[0], lbl[1]);
2386                        goto free_ab_and_return;
2387                }
2388                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2389                        die("unable to read files to diff");
2390                /* Quite common confusing case */
2391                if (mf1.size == mf2.size &&
2392                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2393                        if (must_show_header)
2394                                fprintf(o->file, "%s", header.buf);
2395                        goto free_ab_and_return;
2396                }
2397                fprintf(o->file, "%s", header.buf);
2398                strbuf_reset(&header);
2399                if (DIFF_OPT_TST(o, BINARY))
2400                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2401                else
2402                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2403                                line_prefix, lbl[0], lbl[1]);
2404                o->found_changes = 1;
2405        } else {
2406                /* Crazy xdl interfaces.. */
2407                const char *diffopts = getenv("GIT_DIFF_OPTS");
2408                const char *v;
2409                xpparam_t xpp;
2410                xdemitconf_t xecfg;
2411                struct emit_callback ecbdata;
2412                const struct userdiff_funcname *pe;
2413
2414                if (must_show_header) {
2415                        fprintf(o->file, "%s", header.buf);
2416                        strbuf_reset(&header);
2417                }
2418
2419                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2420                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2421
2422                pe = diff_funcname_pattern(one);
2423                if (!pe)
2424                        pe = diff_funcname_pattern(two);
2425
2426                memset(&xpp, 0, sizeof(xpp));
2427                memset(&xecfg, 0, sizeof(xecfg));
2428                memset(&ecbdata, 0, sizeof(ecbdata));
2429                ecbdata.label_path = lbl;
2430                ecbdata.color_diff = want_color(o->use_color);
2431                ecbdata.ws_rule = whitespace_rule(name_b);
2432                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2433                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2434                ecbdata.opt = o;
2435                ecbdata.header = header.len ? &header : NULL;
2436                xpp.flags = o->xdl_opts;
2437                xecfg.ctxlen = o->context;
2438                xecfg.interhunkctxlen = o->interhunkcontext;
2439                xecfg.flags = XDL_EMIT_FUNCNAMES;
2440                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2441                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2442                if (pe)
2443                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2444                if (!diffopts)
2445                        ;
2446                else if (skip_prefix(diffopts, "--unified=", &v))
2447                        xecfg.ctxlen = strtoul(v, NULL, 10);
2448                else if (skip_prefix(diffopts, "-u", &v))
2449                        xecfg.ctxlen = strtoul(v, NULL, 10);
2450                if (o->word_diff)
2451                        init_diff_words_data(&ecbdata, o, one, two);
2452                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2453                                  &xpp, &xecfg))
2454                        die("unable to generate diff for %s", one->path);
2455                if (o->word_diff)
2456                        free_diff_words_data(&ecbdata);
2457                if (textconv_one)
2458                        free(mf1.ptr);
2459                if (textconv_two)
2460                        free(mf2.ptr);
2461                xdiff_clear_find_func(&xecfg);
2462        }
2463
2464 free_ab_and_return:
2465        strbuf_release(&header);
2466        diff_free_filespec_data(one);
2467        diff_free_filespec_data(two);
2468        free(a_one);
2469        free(b_two);
2470        return;
2471}
2472
2473static void builtin_diffstat(const char *name_a, const char *name_b,
2474                             struct diff_filespec *one,
2475                             struct diff_filespec *two,
2476                             struct diffstat_t *diffstat,
2477                             struct diff_options *o,
2478                             struct diff_filepair *p)
2479{
2480        mmfile_t mf1, mf2;
2481        struct diffstat_file *data;
2482        int same_contents;
2483        int complete_rewrite = 0;
2484
2485        if (!DIFF_PAIR_UNMERGED(p)) {
2486                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2487                        complete_rewrite = 1;
2488        }
2489
2490        data = diffstat_add(diffstat, name_a, name_b);
2491        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2492
2493        if (!one || !two) {
2494                data->is_unmerged = 1;
2495                return;
2496        }
2497
2498        same_contents = !oidcmp(&one->oid, &two->oid);
2499
2500        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2501                data->is_binary = 1;
2502                if (same_contents) {
2503                        data->added = 0;
2504                        data->deleted = 0;
2505                } else {
2506                        data->added = diff_filespec_size(two);
2507                        data->deleted = diff_filespec_size(one);
2508                }
2509        }
2510
2511        else if (complete_rewrite) {
2512                diff_populate_filespec(one, 0);
2513                diff_populate_filespec(two, 0);
2514                data->deleted = count_lines(one->data, one->size);
2515                data->added = count_lines(two->data, two->size);
2516        }
2517
2518        else if (!same_contents) {
2519                /* Crazy xdl interfaces.. */
2520                xpparam_t xpp;
2521                xdemitconf_t xecfg;
2522
2523                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2524                        die("unable to read files to diff");
2525
2526                memset(&xpp, 0, sizeof(xpp));
2527                memset(&xecfg, 0, sizeof(xecfg));
2528                xpp.flags = o->xdl_opts;
2529                xecfg.ctxlen = o->context;
2530                xecfg.interhunkctxlen = o->interhunkcontext;
2531                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2532                                  &xpp, &xecfg))
2533                        die("unable to generate diffstat for %s", one->path);
2534        }
2535
2536        diff_free_filespec_data(one);
2537        diff_free_filespec_data(two);
2538}
2539
2540static void builtin_checkdiff(const char *name_a, const char *name_b,
2541                              const char *attr_path,
2542                              struct diff_filespec *one,
2543                              struct diff_filespec *two,
2544                              struct diff_options *o)
2545{
2546        mmfile_t mf1, mf2;
2547        struct checkdiff_t data;
2548
2549        if (!two)
2550                return;
2551
2552        memset(&data, 0, sizeof(data));
2553        data.filename = name_b ? name_b : name_a;
2554        data.lineno = 0;
2555        data.o = o;
2556        data.ws_rule = whitespace_rule(attr_path);
2557        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2558
2559        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2560                die("unable to read files to diff");
2561
2562        /*
2563         * All the other codepaths check both sides, but not checking
2564         * the "old" side here is deliberate.  We are checking the newly
2565         * introduced changes, and as long as the "new" side is text, we
2566         * can and should check what it introduces.
2567         */
2568        if (diff_filespec_is_binary(two))
2569                goto free_and_return;
2570        else {
2571                /* Crazy xdl interfaces.. */
2572                xpparam_t xpp;
2573                xdemitconf_t xecfg;
2574
2575                memset(&xpp, 0, sizeof(xpp));
2576                memset(&xecfg, 0, sizeof(xecfg));
2577                xecfg.ctxlen = 1; /* at least one context line */
2578                xpp.flags = 0;
2579                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2580                                  &xpp, &xecfg))
2581                        die("unable to generate checkdiff for %s", one->path);
2582
2583                if (data.ws_rule & WS_BLANK_AT_EOF) {
2584                        struct emit_callback ecbdata;
2585                        int blank_at_eof;
2586
2587                        ecbdata.ws_rule = data.ws_rule;
2588                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2589                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2590
2591                        if (blank_at_eof) {
2592                                static char *err;
2593                                if (!err)
2594                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2595                                fprintf(o->file, "%s:%d: %s.\n",
2596                                        data.filename, blank_at_eof, err);
2597                                data.status = 1; /* report errors */
2598                        }
2599                }
2600        }
2601 free_and_return:
2602        diff_free_filespec_data(one);
2603        diff_free_filespec_data(two);
2604        if (data.status)
2605                DIFF_OPT_SET(o, CHECK_FAILED);
2606}
2607
2608struct diff_filespec *alloc_filespec(const char *path)
2609{
2610        struct diff_filespec *spec;
2611
2612        FLEXPTR_ALLOC_STR(spec, path, path);
2613        spec->count = 1;
2614        spec->is_binary = -1;
2615        return spec;
2616}
2617
2618void free_filespec(struct diff_filespec *spec)
2619{
2620        if (!--spec->count) {
2621                diff_free_filespec_data(spec);
2622                free(spec);
2623        }
2624}
2625
2626void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2627                   int sha1_valid, unsigned short mode)
2628{
2629        if (mode) {
2630                spec->mode = canon_mode(mode);
2631                hashcpy(spec->oid.hash, sha1);
2632                spec->oid_valid = sha1_valid;
2633        }
2634}
2635
2636/*
2637 * Given a name and sha1 pair, if the index tells us the file in
2638 * the work tree has that object contents, return true, so that
2639 * prepare_temp_file() does not have to inflate and extract.
2640 */
2641static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2642{
2643        const struct cache_entry *ce;
2644        struct stat st;
2645        int pos, len;
2646
2647        /*
2648         * We do not read the cache ourselves here, because the
2649         * benchmark with my previous version that always reads cache
2650         * shows that it makes things worse for diff-tree comparing
2651         * two linux-2.6 kernel trees in an already checked out work
2652         * tree.  This is because most diff-tree comparisons deal with
2653         * only a small number of files, while reading the cache is
2654         * expensive for a large project, and its cost outweighs the
2655         * savings we get by not inflating the object to a temporary
2656         * file.  Practically, this code only helps when we are used
2657         * by diff-cache --cached, which does read the cache before
2658         * calling us.
2659         */
2660        if (!active_cache)
2661                return 0;
2662
2663        /* We want to avoid the working directory if our caller
2664         * doesn't need the data in a normal file, this system
2665         * is rather slow with its stat/open/mmap/close syscalls,
2666         * and the object is contained in a pack file.  The pack
2667         * is probably already open and will be faster to obtain
2668         * the data through than the working directory.  Loose
2669         * objects however would tend to be slower as they need
2670         * to be individually opened and inflated.
2671         */
2672        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2673                return 0;
2674
2675        /*
2676         * Similarly, if we'd have to convert the file contents anyway, that
2677         * makes the optimization not worthwhile.
2678         */
2679        if (!want_file && would_convert_to_git(name))
2680                return 0;
2681
2682        len = strlen(name);
2683        pos = cache_name_pos(name, len);
2684        if (pos < 0)
2685                return 0;
2686        ce = active_cache[pos];
2687
2688        /*
2689         * This is not the sha1 we are looking for, or
2690         * unreusable because it is not a regular file.
2691         */
2692        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2693                return 0;
2694
2695        /*
2696         * If ce is marked as "assume unchanged", there is no
2697         * guarantee that work tree matches what we are looking for.
2698         */
2699        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2700                return 0;
2701
2702        /*
2703         * If ce matches the file in the work tree, we can reuse it.
2704         */
2705        if (ce_uptodate(ce) ||
2706            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2707                return 1;
2708
2709        return 0;
2710}
2711
2712static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2713{
2714        struct strbuf buf = STRBUF_INIT;
2715        char *dirty = "";
2716
2717        /* Are we looking at the work tree? */
2718        if (s->dirty_submodule)
2719                dirty = "-dirty";
2720
2721        strbuf_addf(&buf, "Subproject commit %s%s\n",
2722                    oid_to_hex(&s->oid), dirty);
2723        s->size = buf.len;
2724        if (size_only) {
2725                s->data = NULL;
2726                strbuf_release(&buf);
2727        } else {
2728                s->data = strbuf_detach(&buf, NULL);
2729                s->should_free = 1;
2730        }
2731        return 0;
2732}
2733
2734/*
2735 * While doing rename detection and pickaxe operation, we may need to
2736 * grab the data for the blob (or file) for our own in-core comparison.
2737 * diff_filespec has data and size fields for this purpose.
2738 */
2739int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2740{
2741        int size_only = flags & CHECK_SIZE_ONLY;
2742        int err = 0;
2743        /*
2744         * demote FAIL to WARN to allow inspecting the situation
2745         * instead of refusing.
2746         */
2747        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2748                                    ? SAFE_CRLF_WARN
2749                                    : safe_crlf);
2750
2751        if (!DIFF_FILE_VALID(s))
2752                die("internal error: asking to populate invalid file.");
2753        if (S_ISDIR(s->mode))
2754                return -1;
2755
2756        if (s->data)
2757                return 0;
2758
2759        if (size_only && 0 < s->size)
2760                return 0;
2761
2762        if (S_ISGITLINK(s->mode))
2763                return diff_populate_gitlink(s, size_only);
2764
2765        if (!s->oid_valid ||
2766            reuse_worktree_file(s->path, s->oid.hash, 0)) {
2767                struct strbuf buf = STRBUF_INIT;
2768                struct stat st;
2769                int fd;
2770
2771                if (lstat(s->path, &st) < 0) {
2772                        if (errno == ENOENT) {
2773                        err_empty:
2774                                err = -1;
2775                        empty:
2776                                s->data = (char *)"";
2777                                s->size = 0;
2778                                return err;
2779                        }
2780                }
2781                s->size = xsize_t(st.st_size);
2782                if (!s->size)
2783                        goto empty;
2784                if (S_ISLNK(st.st_mode)) {
2785                        struct strbuf sb = STRBUF_INIT;
2786
2787                        if (strbuf_readlink(&sb, s->path, s->size))
2788                                goto err_empty;
2789                        s->size = sb.len;
2790                        s->data = strbuf_detach(&sb, NULL);
2791                        s->should_free = 1;
2792                        return 0;
2793                }
2794                if (size_only)
2795                        return 0;
2796                if ((flags & CHECK_BINARY) &&
2797                    s->size > big_file_threshold && s->is_binary == -1) {
2798                        s->is_binary = 1;
2799                        return 0;
2800                }
2801                fd = open(s->path, O_RDONLY);
2802                if (fd < 0)
2803                        goto err_empty;
2804                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2805                close(fd);
2806                s->should_munmap = 1;
2807
2808                /*
2809                 * Convert from working tree format to canonical git format
2810                 */
2811                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2812                        size_t size = 0;
2813                        munmap(s->data, s->size);
2814                        s->should_munmap = 0;
2815                        s->data = strbuf_detach(&buf, &size);
2816                        s->size = size;
2817                        s->should_free = 1;
2818                }
2819        }
2820        else {
2821                enum object_type type;
2822                if (size_only || (flags & CHECK_BINARY)) {
2823                        type = sha1_object_info(s->oid.hash, &s->size);
2824                        if (type < 0)
2825                                die("unable to read %s",
2826                                    oid_to_hex(&s->oid));
2827                        if (size_only)
2828                                return 0;
2829                        if (s->size > big_file_threshold && s->is_binary == -1) {
2830                                s->is_binary = 1;
2831                                return 0;
2832                        }
2833                }
2834                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2835                if (!s->data)
2836                        die("unable to read %s", oid_to_hex(&s->oid));
2837                s->should_free = 1;
2838        }
2839        return 0;
2840}
2841
2842void diff_free_filespec_blob(struct diff_filespec *s)
2843{
2844        if (s->should_free)
2845                free(s->data);
2846        else if (s->should_munmap)
2847                munmap(s->data, s->size);
2848
2849        if (s->should_free || s->should_munmap) {
2850                s->should_free = s->should_munmap = 0;
2851                s->data = NULL;
2852        }
2853}
2854
2855void diff_free_filespec_data(struct diff_filespec *s)
2856{
2857        diff_free_filespec_blob(s);
2858        free(s->cnt_data);
2859        s->cnt_data = NULL;
2860}
2861
2862static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2863                           void *blob,
2864                           unsigned long size,
2865                           const struct object_id *oid,
2866                           int mode)
2867{
2868        int fd;
2869        struct strbuf buf = STRBUF_INIT;
2870        struct strbuf template = STRBUF_INIT;
2871        char *path_dup = xstrdup(path);
2872        const char *base = basename(path_dup);
2873
2874        /* Generate "XXXXXX_basename.ext" */
2875        strbuf_addstr(&template, "XXXXXX_");
2876        strbuf_addstr(&template, base);
2877
2878        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2879        if (fd < 0)
2880                die_errno("unable to create temp-file");
2881        if (convert_to_working_tree(path,
2882                        (const char *)blob, (size_t)size, &buf)) {
2883                blob = buf.buf;
2884                size = buf.len;
2885        }
2886        if (write_in_full(fd, blob, size) != size)
2887                die_errno("unable to write temp-file");
2888        close_tempfile(&temp->tempfile);
2889        temp->name = get_tempfile_path(&temp->tempfile);
2890        oid_to_hex_r(temp->hex, oid);
2891        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2892        strbuf_release(&buf);
2893        strbuf_release(&template);
2894        free(path_dup);
2895}
2896
2897static struct diff_tempfile *prepare_temp_file(const char *name,
2898                struct diff_filespec *one)
2899{
2900        struct diff_tempfile *temp = claim_diff_tempfile();
2901
2902        if (!DIFF_FILE_VALID(one)) {
2903        not_a_valid_file:
2904                /* A '-' entry produces this for file-2, and
2905                 * a '+' entry produces this for file-1.
2906                 */
2907                temp->name = "/dev/null";
2908                xsnprintf(temp->hex, sizeof(temp->hex), ".");
2909                xsnprintf(temp->mode, sizeof(temp->mode), ".");
2910                return temp;
2911        }
2912
2913        if (!S_ISGITLINK(one->mode) &&
2914            (!one->oid_valid ||
2915             reuse_worktree_file(name, one->oid.hash, 1))) {
2916                struct stat st;
2917                if (lstat(name, &st) < 0) {
2918                        if (errno == ENOENT)
2919                                goto not_a_valid_file;
2920                        die_errno("stat(%s)", name);
2921                }
2922                if (S_ISLNK(st.st_mode)) {
2923                        struct strbuf sb = STRBUF_INIT;
2924                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2925                                die_errno("readlink(%s)", name);
2926                        prep_temp_blob(name, temp, sb.buf, sb.len,
2927                                       (one->oid_valid ?
2928                                        &one->oid : &null_oid),
2929                                       (one->oid_valid ?
2930                                        one->mode : S_IFLNK));
2931                        strbuf_release(&sb);
2932                }
2933                else {
2934                        /* we can borrow from the file in the work tree */
2935                        temp->name = name;
2936                        if (!one->oid_valid)
2937                                sha1_to_hex_r(temp->hex, null_sha1);
2938                        else
2939                                sha1_to_hex_r(temp->hex, one->oid.hash);
2940                        /* Even though we may sometimes borrow the
2941                         * contents from the work tree, we always want
2942                         * one->mode.  mode is trustworthy even when
2943                         * !(one->sha1_valid), as long as
2944                         * DIFF_FILE_VALID(one).
2945                         */
2946                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2947                }
2948                return temp;
2949        }
2950        else {
2951                if (diff_populate_filespec(one, 0))
2952                        die("cannot read data blob for %s", one->path);
2953                prep_temp_blob(name, temp, one->data, one->size,
2954                               &one->oid, one->mode);
2955        }
2956        return temp;
2957}
2958
2959static void add_external_diff_name(struct argv_array *argv,
2960                                   const char *name,
2961                                   struct diff_filespec *df)
2962{
2963        struct diff_tempfile *temp = prepare_temp_file(name, df);
2964        argv_array_push(argv, temp->name);
2965        argv_array_push(argv, temp->hex);
2966        argv_array_push(argv, temp->mode);
2967}
2968
2969/* An external diff command takes:
2970 *
2971 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2972 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2973 *
2974 */
2975static void run_external_diff(const char *pgm,
2976                              const char *name,
2977                              const char *other,
2978                              struct diff_filespec *one,
2979                              struct diff_filespec *two,
2980                              const char *xfrm_msg,
2981                              int complete_rewrite,
2982                              struct diff_options *o)
2983{
2984        struct argv_array argv = ARGV_ARRAY_INIT;
2985        struct argv_array env = ARGV_ARRAY_INIT;
2986        struct diff_queue_struct *q = &diff_queued_diff;
2987
2988        argv_array_push(&argv, pgm);
2989        argv_array_push(&argv, name);
2990
2991        if (one && two) {
2992                add_external_diff_name(&argv, name, one);
2993                if (!other)
2994                        add_external_diff_name(&argv, name, two);
2995                else {
2996                        add_external_diff_name(&argv, other, two);
2997                        argv_array_push(&argv, other);
2998                        argv_array_push(&argv, xfrm_msg);
2999                }
3000        }
3001
3002        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3003        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3004
3005        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3006                die(_("external diff died, stopping at %s"), name);
3007
3008        remove_tempfile();
3009        argv_array_clear(&argv);
3010        argv_array_clear(&env);
3011}
3012
3013static int similarity_index(struct diff_filepair *p)
3014{
3015        return p->score * 100 / MAX_SCORE;
3016}
3017
3018static void fill_metainfo(struct strbuf *msg,
3019                          const char *name,
3020                          const char *other,
3021                          struct diff_filespec *one,
3022                          struct diff_filespec *two,
3023                          struct diff_options *o,
3024                          struct diff_filepair *p,
3025                          int *must_show_header,
3026                          int use_color)
3027{
3028        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3029        const char *reset = diff_get_color(use_color, DIFF_RESET);
3030        const char *line_prefix = diff_line_prefix(o);
3031
3032        *must_show_header = 1;
3033        strbuf_init(msg, PATH_MAX * 2 + 300);
3034        switch (p->status) {
3035        case DIFF_STATUS_COPIED:
3036                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3037                            line_prefix, set, similarity_index(p));
3038                strbuf_addf(msg, "%s\n%s%scopy from ",
3039                            reset,  line_prefix, set);
3040                quote_c_style(name, msg, NULL, 0);
3041                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3042                quote_c_style(other, msg, NULL, 0);
3043                strbuf_addf(msg, "%s\n", reset);
3044                break;
3045        case DIFF_STATUS_RENAMED:
3046                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3047                            line_prefix, set, similarity_index(p));
3048                strbuf_addf(msg, "%s\n%s%srename from ",
3049                            reset, line_prefix, set);
3050                quote_c_style(name, msg, NULL, 0);
3051                strbuf_addf(msg, "%s\n%s%srename to ",
3052                            reset, line_prefix, set);
3053                quote_c_style(other, msg, NULL, 0);
3054                strbuf_addf(msg, "%s\n", reset);
3055                break;
3056        case DIFF_STATUS_MODIFIED:
3057                if (p->score) {
3058                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3059                                    line_prefix,
3060                                    set, similarity_index(p), reset);
3061                        break;
3062                }
3063                /* fallthru */
3064        default:
3065                *must_show_header = 0;
3066        }
3067        if (one && two && oidcmp(&one->oid, &two->oid)) {
3068                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3069
3070                if (DIFF_OPT_TST(o, BINARY)) {
3071                        mmfile_t mf;
3072                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3073                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3074                                abbrev = 40;
3075                }
3076                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3077                            find_unique_abbrev(one->oid.hash, abbrev));
3078                strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
3079                if (one->mode == two->mode)
3080                        strbuf_addf(msg, " %06o", one->mode);
3081                strbuf_addf(msg, "%s\n", reset);
3082        }
3083}
3084
3085static void run_diff_cmd(const char *pgm,
3086                         const char *name,
3087                         const char *other,
3088                         const char *attr_path,
3089                         struct diff_filespec *one,
3090                         struct diff_filespec *two,
3091                         struct strbuf *msg,
3092                         struct diff_options *o,
3093                         struct diff_filepair *p)
3094{
3095        const char *xfrm_msg = NULL;
3096        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3097        int must_show_header = 0;
3098
3099
3100        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3101                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3102                if (drv && drv->external)
3103                        pgm = drv->external;
3104        }
3105
3106        if (msg) {
3107                /*
3108                 * don't use colors when the header is intended for an
3109                 * external diff driver
3110                 */
3111                fill_metainfo(msg, name, other, one, two, o, p,
3112                              &must_show_header,
3113                              want_color(o->use_color) && !pgm);
3114                xfrm_msg = msg->len ? msg->buf : NULL;
3115        }
3116
3117        if (pgm) {
3118                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3119                                  complete_rewrite, o);
3120                return;
3121        }
3122        if (one && two)
3123                builtin_diff(name, other ? other : name,
3124                             one, two, xfrm_msg, must_show_header,
3125                             o, complete_rewrite);
3126        else
3127                fprintf(o->file, "* Unmerged path %s\n", name);
3128}
3129
3130static void diff_fill_sha1_info(struct diff_filespec *one)
3131{
3132        if (DIFF_FILE_VALID(one)) {
3133                if (!one->oid_valid) {
3134                        struct stat st;
3135                        if (one->is_stdin) {
3136                                oidclr(&one->oid);
3137                                return;
3138                        }
3139                        if (lstat(one->path, &st) < 0)
3140                                die_errno("stat '%s'", one->path);
3141                        if (index_path(one->oid.hash, one->path, &st, 0))
3142                                die("cannot hash %s", one->path);
3143                }
3144        }
3145        else
3146                oidclr(&one->oid);
3147}
3148
3149static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3150{
3151        /* Strip the prefix but do not molest /dev/null and absolute paths */
3152        if (*namep && **namep != '/') {
3153                *namep += prefix_length;
3154                if (**namep == '/')
3155                        ++*namep;
3156        }
3157        if (*otherp && **otherp != '/') {
3158                *otherp += prefix_length;
3159                if (**otherp == '/')
3160                        ++*otherp;
3161        }
3162}
3163
3164static void run_diff(struct diff_filepair *p, struct diff_options *o)
3165{
3166        const char *pgm = external_diff();
3167        struct strbuf msg;
3168        struct diff_filespec *one = p->one;
3169        struct diff_filespec *two = p->two;
3170        const char *name;
3171        const char *other;
3172        const char *attr_path;
3173
3174        name  = p->one->path;
3175        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3176        attr_path = name;
3177        if (o->prefix_length)
3178                strip_prefix(o->prefix_length, &name, &other);
3179
3180        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3181                pgm = NULL;
3182
3183        if (DIFF_PAIR_UNMERGED(p)) {
3184                run_diff_cmd(pgm, name, NULL, attr_path,
3185                             NULL, NULL, NULL, o, p);
3186                return;
3187        }
3188
3189        diff_fill_sha1_info(one);
3190        diff_fill_sha1_info(two);
3191
3192        if (!pgm &&
3193            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3194            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3195                /*
3196                 * a filepair that changes between file and symlink
3197                 * needs to be split into deletion and creation.
3198                 */
3199                struct diff_filespec *null = alloc_filespec(two->path);
3200                run_diff_cmd(NULL, name, other, attr_path,
3201                             one, null, &msg, o, p);
3202                free(null);
3203                strbuf_release(&msg);
3204
3205                null = alloc_filespec(one->path);
3206                run_diff_cmd(NULL, name, other, attr_path,
3207                             null, two, &msg, o, p);
3208                free(null);
3209        }
3210        else
3211                run_diff_cmd(pgm, name, other, attr_path,
3212                             one, two, &msg, o, p);
3213
3214        strbuf_release(&msg);
3215}
3216
3217static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3218                         struct diffstat_t *diffstat)
3219{
3220        const char *name;
3221        const char *other;
3222
3223        if (DIFF_PAIR_UNMERGED(p)) {
3224                /* unmerged */
3225                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3226                return;
3227        }
3228
3229        name = p->one->path;
3230        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3231
3232        if (o->prefix_length)
3233                strip_prefix(o->prefix_length, &name, &other);
3234
3235        diff_fill_sha1_info(p->one);
3236        diff_fill_sha1_info(p->two);
3237
3238        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3239}
3240
3241static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3242{
3243        const char *name;
3244        const char *other;
3245        const char *attr_path;
3246
3247        if (DIFF_PAIR_UNMERGED(p)) {
3248                /* unmerged */
3249                return;
3250        }
3251
3252        name = p->one->path;
3253        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3254        attr_path = other ? other : name;
3255
3256        if (o->prefix_length)
3257                strip_prefix(o->prefix_length, &name, &other);
3258
3259        diff_fill_sha1_info(p->one);
3260        diff_fill_sha1_info(p->two);
3261
3262        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3263}
3264
3265void diff_setup(struct diff_options *options)
3266{
3267        memcpy(options, &default_diff_options, sizeof(*options));
3268
3269        options->file = stdout;
3270
3271        options->line_termination = '\n';
3272        options->break_opt = -1;
3273        options->rename_limit = -1;
3274        options->dirstat_permille = diff_dirstat_permille_default;
3275        options->context = diff_context_default;
3276        options->ws_error_highlight = WSEH_NEW;
3277        DIFF_OPT_SET(options, RENAME_EMPTY);
3278
3279        /* pathchange left =NULL by default */
3280        options->change = diff_change;
3281        options->add_remove = diff_addremove;
3282        options->use_color = diff_use_color_default;
3283        options->detect_rename = diff_detect_rename_default;
3284        options->xdl_opts |= diff_algorithm;
3285        if (diff_compaction_heuristic)
3286                DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
3287
3288        options->orderfile = diff_order_file_cfg;
3289
3290        if (diff_no_prefix) {
3291                options->a_prefix = options->b_prefix = "";
3292        } else if (!diff_mnemonic_prefix) {
3293                options->a_prefix = "a/";
3294                options->b_prefix = "b/";
3295        }
3296}
3297
3298void diff_setup_done(struct diff_options *options)
3299{
3300        int count = 0;
3301
3302        if (options->set_default)
3303                options->set_default(options);
3304
3305        if (options->output_format & DIFF_FORMAT_NAME)
3306                count++;
3307        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3308                count++;
3309        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3310                count++;
3311        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3312                count++;
3313        if (count > 1)
3314                die("--name-only, --name-status, --check and -s are mutually exclusive");
3315
3316        /*
3317         * Most of the time we can say "there are changes"
3318         * only by checking if there are changed paths, but
3319         * --ignore-whitespace* options force us to look
3320         * inside contents.
3321         */
3322
3323        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3324            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3325            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3326                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3327        else
3328                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3329
3330        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3331                options->detect_rename = DIFF_DETECT_COPY;
3332
3333        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3334                options->prefix = NULL;
3335        if (options->prefix)
3336                options->prefix_length = strlen(options->prefix);
3337        else
3338                options->prefix_length = 0;
3339
3340        if (options->output_format & (DIFF_FORMAT_NAME |
3341                                      DIFF_FORMAT_NAME_STATUS |
3342                                      DIFF_FORMAT_CHECKDIFF |
3343                                      DIFF_FORMAT_NO_OUTPUT))
3344                options->output_format &= ~(DIFF_FORMAT_RAW |
3345                                            DIFF_FORMAT_NUMSTAT |
3346                                            DIFF_FORMAT_DIFFSTAT |
3347                                            DIFF_FORMAT_SHORTSTAT |
3348                                            DIFF_FORMAT_DIRSTAT |
3349                                            DIFF_FORMAT_SUMMARY |
3350                                            DIFF_FORMAT_PATCH);
3351
3352        /*
3353         * These cases always need recursive; we do not drop caller-supplied
3354         * recursive bits for other formats here.
3355         */
3356        if (options->output_format & (DIFF_FORMAT_PATCH |
3357                                      DIFF_FORMAT_NUMSTAT |
3358                                      DIFF_FORMAT_DIFFSTAT |
3359                                      DIFF_FORMAT_SHORTSTAT |
3360                                      DIFF_FORMAT_DIRSTAT |
3361                                      DIFF_FORMAT_SUMMARY |
3362                                      DIFF_FORMAT_CHECKDIFF))
3363                DIFF_OPT_SET(options, RECURSIVE);
3364        /*
3365         * Also pickaxe would not work very well if you do not say recursive
3366         */
3367        if (options->pickaxe)
3368                DIFF_OPT_SET(options, RECURSIVE);
3369        /*
3370         * When patches are generated, submodules diffed against the work tree
3371         * must be checked for dirtiness too so it can be shown in the output
3372         */
3373        if (options->output_format & DIFF_FORMAT_PATCH)
3374                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3375
3376        if (options->detect_rename && options->rename_limit < 0)
3377                options->rename_limit = diff_rename_limit_default;
3378        if (options->setup & DIFF_SETUP_USE_CACHE) {
3379                if (!active_cache)
3380                        /* read-cache does not die even when it fails
3381                         * so it is safe for us to do this here.  Also
3382                         * it does not smudge active_cache or active_nr
3383                         * when it fails, so we do not have to worry about
3384                         * cleaning it up ourselves either.
3385                         */
3386                        read_cache();
3387        }
3388        if (options->abbrev <= 0 || 40 < options->abbrev)
3389                options->abbrev = 40; /* full */
3390
3391        /*
3392         * It does not make sense to show the first hit we happened
3393         * to have found.  It does not make sense not to return with
3394         * exit code in such a case either.
3395         */
3396        if (DIFF_OPT_TST(options, QUICK)) {
3397                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3398                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3399        }
3400
3401        options->diff_path_counter = 0;
3402
3403        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3404                die(_("--follow requires exactly one pathspec"));
3405}
3406
3407static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3408{
3409        char c, *eq;
3410        int len;
3411
3412        if (*arg != '-')
3413                return 0;
3414        c = *++arg;
3415        if (!c)
3416                return 0;
3417        if (c == arg_short) {
3418                c = *++arg;
3419                if (!c)
3420                        return 1;
3421                if (val && isdigit(c)) {
3422                        char *end;
3423                        int n = strtoul(arg, &end, 10);
3424                        if (*end)
3425                                return 0;
3426                        *val = n;
3427                        return 1;
3428                }
3429                return 0;
3430        }
3431        if (c != '-')
3432                return 0;
3433        arg++;
3434        eq = strchrnul(arg, '=');
3435        len = eq - arg;
3436        if (!len || strncmp(arg, arg_long, len))
3437                return 0;
3438        if (*eq) {
3439                int n;
3440                char *end;
3441                if (!isdigit(*++eq))
3442                        return 0;
3443                n = strtoul(eq, &end, 10);
3444                if (*end)
3445                        return 0;
3446                *val = n;
3447        }
3448        return 1;
3449}
3450
3451static int diff_scoreopt_parse(const char *opt);
3452
3453static inline int short_opt(char opt, const char **argv,
3454                            const char **optarg)
3455{
3456        const char *arg = argv[0];
3457        if (arg[0] != '-' || arg[1] != opt)
3458                return 0;
3459        if (arg[2] != '\0') {
3460                *optarg = arg + 2;
3461                return 1;
3462        }
3463        if (!argv[1])
3464                die("Option '%c' requires a value", opt);
3465        *optarg = argv[1];
3466        return 2;
3467}
3468
3469int parse_long_opt(const char *opt, const char **argv,
3470                   const char **optarg)
3471{
3472        const char *arg = argv[0];
3473        if (!skip_prefix(arg, "--", &arg))
3474                return 0;
3475        if (!skip_prefix(arg, opt, &arg))
3476                return 0;
3477        if (*arg == '=') { /* stuck form: --option=value */
3478                *optarg = arg + 1;
3479                return 1;
3480        }
3481        if (*arg != '\0')
3482                return 0;
3483        /* separate form: --option value */
3484        if (!argv[1])
3485                die("Option '--%s' requires a value", opt);
3486        *optarg = argv[1];
3487        return 2;
3488}
3489
3490static int stat_opt(struct diff_options *options, const char **av)
3491{
3492        const char *arg = av[0];
3493        char *end;
3494        int width = options->stat_width;
3495        int name_width = options->stat_name_width;
3496        int graph_width = options->stat_graph_width;
3497        int count = options->stat_count;
3498        int argcount = 1;
3499
3500        if (!skip_prefix(arg, "--stat", &arg))
3501                die("BUG: stat option does not begin with --stat: %s", arg);
3502        end = (char *)arg;
3503
3504        switch (*arg) {
3505        case '-':
3506                if (skip_prefix(arg, "-width", &arg)) {
3507                        if (*arg == '=')
3508                                width = strtoul(arg + 1, &end, 10);
3509                        else if (!*arg && !av[1])
3510                                die("Option '--stat-width' requires a value");
3511                        else if (!*arg) {
3512                                width = strtoul(av[1], &end, 10);
3513                                argcount = 2;
3514                        }
3515                } else if (skip_prefix(arg, "-name-width", &arg)) {
3516                        if (*arg == '=')
3517                                name_width = strtoul(arg + 1, &end, 10);
3518                        else if (!*arg && !av[1])
3519                                die("Option '--stat-name-width' requires a value");
3520                        else if (!*arg) {
3521                                name_width = strtoul(av[1], &end, 10);
3522                                argcount = 2;
3523                        }
3524                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3525                        if (*arg == '=')
3526                                graph_width = strtoul(arg + 1, &end, 10);
3527                        else if (!*arg && !av[1])
3528                                die("Option '--stat-graph-width' requires a value");
3529                        else if (!*arg) {
3530                                graph_width = strtoul(av[1], &end, 10);
3531                                argcount = 2;
3532                        }
3533                } else if (skip_prefix(arg, "-count", &arg)) {
3534                        if (*arg == '=')
3535                                count = strtoul(arg + 1, &end, 10);
3536                        else if (!*arg && !av[1])
3537                                die("Option '--stat-count' requires a value");
3538                        else if (!*arg) {
3539                                count = strtoul(av[1], &end, 10);
3540                                argcount = 2;
3541                        }
3542                }
3543                break;
3544        case '=':
3545                width = strtoul(arg+1, &end, 10);
3546                if (*end == ',')
3547                        name_width = strtoul(end+1, &end, 10);
3548                if (*end == ',')
3549                        count = strtoul(end+1, &end, 10);
3550        }
3551
3552        /* Important! This checks all the error cases! */
3553        if (*end)
3554                return 0;
3555        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3556        options->stat_name_width = name_width;
3557        options->stat_graph_width = graph_width;
3558        options->stat_width = width;
3559        options->stat_count = count;
3560        return argcount;
3561}
3562
3563static int parse_dirstat_opt(struct diff_options *options, const char *params)
3564{
3565        struct strbuf errmsg = STRBUF_INIT;
3566        if (parse_dirstat_params(options, params, &errmsg))
3567                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3568                    errmsg.buf);
3569        strbuf_release(&errmsg);
3570        /*
3571         * The caller knows a dirstat-related option is given from the command
3572         * line; allow it to say "return this_function();"
3573         */
3574        options->output_format |= DIFF_FORMAT_DIRSTAT;
3575        return 1;
3576}
3577
3578static int parse_submodule_opt(struct diff_options *options, const char *value)
3579{
3580        if (parse_submodule_params(options, value))
3581                die(_("Failed to parse --submodule option parameter: '%s'"),
3582                        value);
3583        return 1;
3584}
3585
3586static const char diff_status_letters[] = {
3587        DIFF_STATUS_ADDED,
3588        DIFF_STATUS_COPIED,
3589        DIFF_STATUS_DELETED,
3590        DIFF_STATUS_MODIFIED,
3591        DIFF_STATUS_RENAMED,
3592        DIFF_STATUS_TYPE_CHANGED,
3593        DIFF_STATUS_UNKNOWN,
3594        DIFF_STATUS_UNMERGED,
3595        DIFF_STATUS_FILTER_AON,
3596        DIFF_STATUS_FILTER_BROKEN,
3597        '\0',
3598};
3599
3600static unsigned int filter_bit['Z' + 1];
3601
3602static void prepare_filter_bits(void)
3603{
3604        int i;
3605
3606        if (!filter_bit[DIFF_STATUS_ADDED]) {
3607                for (i = 0; diff_status_letters[i]; i++)
3608                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3609        }
3610}
3611
3612static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3613{
3614        return opt->filter & filter_bit[(int) status];
3615}
3616
3617static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3618{
3619        int i, optch;
3620
3621        prepare_filter_bits();
3622
3623        /*
3624         * If there is a negation e.g. 'd' in the input, and we haven't
3625         * initialized the filter field with another --diff-filter, start
3626         * from full set of bits, except for AON.
3627         */
3628        if (!opt->filter) {
3629                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3630                        if (optch < 'a' || 'z' < optch)
3631                                continue;
3632                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3633                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3634                        break;
3635                }
3636        }
3637
3638        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3639                unsigned int bit;
3640                int negate;
3641
3642                if ('a' <= optch && optch <= 'z') {
3643                        negate = 1;
3644                        optch = toupper(optch);
3645                } else {
3646                        negate = 0;
3647                }
3648
3649                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3650                if (!bit)
3651                        return optarg[i];
3652                if (negate)
3653                        opt->filter &= ~bit;
3654                else
3655                        opt->filter |= bit;
3656        }
3657        return 0;
3658}
3659
3660static void enable_patch_output(int *fmt) {
3661        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3662        *fmt |= DIFF_FORMAT_PATCH;
3663}
3664
3665static int parse_one_token(const char **arg, const char *token)
3666{
3667        const char *rest;
3668        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3669                *arg = rest;
3670                return 1;
3671        }
3672        return 0;
3673}
3674
3675static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3676{
3677        const char *orig_arg = arg;
3678        unsigned val = 0;
3679        while (*arg) {
3680                if (parse_one_token(&arg, "none"))
3681                        val = 0;
3682                else if (parse_one_token(&arg, "default"))
3683                        val = WSEH_NEW;
3684                else if (parse_one_token(&arg, "all"))
3685                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3686                else if (parse_one_token(&arg, "new"))
3687                        val |= WSEH_NEW;
3688                else if (parse_one_token(&arg, "old"))
3689                        val |= WSEH_OLD;
3690                else if (parse_one_token(&arg, "context"))
3691                        val |= WSEH_CONTEXT;
3692                else {
3693                        error("unknown value after ws-error-highlight=%.*s",
3694                              (int)(arg - orig_arg), orig_arg);
3695                        return 0;
3696                }
3697                if (*arg)
3698                        arg++;
3699        }
3700        opt->ws_error_highlight = val;
3701        return 1;
3702}
3703
3704int diff_opt_parse(struct diff_options *options,
3705                   const char **av, int ac, const char *prefix)
3706{
3707        const char *arg = av[0];
3708        const char *optarg;
3709        int argcount;
3710
3711        if (!prefix)
3712                prefix = "";
3713
3714        /* Output format options */
3715        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3716            || opt_arg(arg, 'U', "unified", &options->context))
3717                enable_patch_output(&options->output_format);
3718        else if (!strcmp(arg, "--raw"))
3719                options->output_format |= DIFF_FORMAT_RAW;
3720        else if (!strcmp(arg, "--patch-with-raw")) {
3721                enable_patch_output(&options->output_format);
3722                options->output_format |= DIFF_FORMAT_RAW;
3723        } else if (!strcmp(arg, "--numstat"))
3724                options->output_format |= DIFF_FORMAT_NUMSTAT;
3725        else if (!strcmp(arg, "--shortstat"))
3726                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3727        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3728                return parse_dirstat_opt(options, "");
3729        else if (skip_prefix(arg, "-X", &arg))
3730                return parse_dirstat_opt(options, arg);
3731        else if (skip_prefix(arg, "--dirstat=", &arg))
3732                return parse_dirstat_opt(options, arg);
3733        else if (!strcmp(arg, "--cumulative"))
3734                return parse_dirstat_opt(options, "cumulative");
3735        else if (!strcmp(arg, "--dirstat-by-file"))
3736                return parse_dirstat_opt(options, "files");
3737        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3738                parse_dirstat_opt(options, "files");
3739                return parse_dirstat_opt(options, arg);
3740        }
3741        else if (!strcmp(arg, "--check"))
3742                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3743        else if (!strcmp(arg, "--summary"))
3744                options->output_format |= DIFF_FORMAT_SUMMARY;
3745        else if (!strcmp(arg, "--patch-with-stat")) {
3746                enable_patch_output(&options->output_format);
3747                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3748        } else if (!strcmp(arg, "--name-only"))
3749                options->output_format |= DIFF_FORMAT_NAME;
3750        else if (!strcmp(arg, "--name-status"))
3751                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3752        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3753                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3754        else if (starts_with(arg, "--stat"))
3755                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3756                return stat_opt(options, av);
3757
3758        /* renames options */
3759        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3760                 !strcmp(arg, "--break-rewrites")) {
3761                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3762                        return error("invalid argument to -B: %s", arg+2);
3763        }
3764        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3765                 !strcmp(arg, "--find-renames")) {
3766                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3767                        return error("invalid argument to -M: %s", arg+2);
3768                options->detect_rename = DIFF_DETECT_RENAME;
3769        }
3770        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3771                options->irreversible_delete = 1;
3772        }
3773        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3774                 !strcmp(arg, "--find-copies")) {
3775                if (options->detect_rename == DIFF_DETECT_COPY)
3776                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3777                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3778                        return error("invalid argument to -C: %s", arg+2);
3779                options->detect_rename = DIFF_DETECT_COPY;
3780        }
3781        else if (!strcmp(arg, "--no-renames"))
3782                options->detect_rename = 0;
3783        else if (!strcmp(arg, "--rename-empty"))
3784                DIFF_OPT_SET(options, RENAME_EMPTY);
3785        else if (!strcmp(arg, "--no-rename-empty"))
3786                DIFF_OPT_CLR(options, RENAME_EMPTY);
3787        else if (!strcmp(arg, "--relative"))
3788                DIFF_OPT_SET(options, RELATIVE_NAME);
3789        else if (skip_prefix(arg, "--relative=", &arg)) {
3790                DIFF_OPT_SET(options, RELATIVE_NAME);
3791                options->prefix = arg;
3792        }
3793
3794        /* xdiff options */
3795        else if (!strcmp(arg, "--minimal"))
3796                DIFF_XDL_SET(options, NEED_MINIMAL);
3797        else if (!strcmp(arg, "--no-minimal"))
3798                DIFF_XDL_CLR(options, NEED_MINIMAL);
3799        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3800                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3801        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3802                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3803        else if (!strcmp(arg, "--ignore-space-at-eol"))
3804                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3805        else if (!strcmp(arg, "--ignore-blank-lines"))
3806                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3807        else if (!strcmp(arg, "--compaction-heuristic"))
3808                DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
3809        else if (!strcmp(arg, "--no-compaction-heuristic"))
3810                DIFF_XDL_CLR(options, COMPACTION_HEURISTIC);
3811        else if (!strcmp(arg, "--patience"))
3812                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3813        else if (!strcmp(arg, "--histogram"))
3814                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3815        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3816                long value = parse_algorithm_value(optarg);
3817                if (value < 0)
3818                        return error("option diff-algorithm accepts \"myers\", "
3819                                     "\"minimal\", \"patience\" and \"histogram\"");
3820                /* clear out previous settings */
3821                DIFF_XDL_CLR(options, NEED_MINIMAL);
3822                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3823                options->xdl_opts |= value;
3824                return argcount;
3825        }
3826
3827        /* flags options */
3828        else if (!strcmp(arg, "--binary")) {
3829                enable_patch_output(&options->output_format);
3830                DIFF_OPT_SET(options, BINARY);
3831        }
3832        else if (!strcmp(arg, "--full-index"))
3833                DIFF_OPT_SET(options, FULL_INDEX);
3834        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3835                DIFF_OPT_SET(options, TEXT);
3836        else if (!strcmp(arg, "-R"))
3837                DIFF_OPT_SET(options, REVERSE_DIFF);
3838        else if (!strcmp(arg, "--find-copies-harder"))
3839                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3840        else if (!strcmp(arg, "--follow"))
3841                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3842        else if (!strcmp(arg, "--no-follow")) {
3843                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3844                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3845        } else if (!strcmp(arg, "--color"))
3846                options->use_color = 1;
3847        else if (skip_prefix(arg, "--color=", &arg)) {
3848                int value = git_config_colorbool(NULL, arg);
3849                if (value < 0)
3850                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3851                options->use_color = value;
3852        }
3853        else if (!strcmp(arg, "--no-color"))
3854                options->use_color = 0;
3855        else if (!strcmp(arg, "--color-words")) {
3856                options->use_color = 1;
3857                options->word_diff = DIFF_WORDS_COLOR;
3858        }
3859        else if (skip_prefix(arg, "--color-words=", &arg)) {
3860                options->use_color = 1;
3861                options->word_diff = DIFF_WORDS_COLOR;
3862                options->word_regex = arg;
3863        }
3864        else if (!strcmp(arg, "--word-diff")) {
3865                if (options->word_diff == DIFF_WORDS_NONE)
3866                        options->word_diff = DIFF_WORDS_PLAIN;
3867        }
3868        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3869                if (!strcmp(arg, "plain"))
3870                        options->word_diff = DIFF_WORDS_PLAIN;
3871                else if (!strcmp(arg, "color")) {
3872                        options->use_color = 1;
3873                        options->word_diff = DIFF_WORDS_COLOR;
3874                }
3875                else if (!strcmp(arg, "porcelain"))
3876                        options->word_diff = DIFF_WORDS_PORCELAIN;
3877                else if (!strcmp(arg, "none"))
3878                        options->word_diff = DIFF_WORDS_NONE;
3879                else
3880                        die("bad --word-diff argument: %s", arg);
3881        }
3882        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3883                if (options->word_diff == DIFF_WORDS_NONE)
3884                        options->word_diff = DIFF_WORDS_PLAIN;
3885                options->word_regex = optarg;
3886                return argcount;
3887        }
3888        else if (!strcmp(arg, "--exit-code"))
3889                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3890        else if (!strcmp(arg, "--quiet"))
3891                DIFF_OPT_SET(options, QUICK);
3892        else if (!strcmp(arg, "--ext-diff"))
3893                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3894        else if (!strcmp(arg, "--no-ext-diff"))
3895                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3896        else if (!strcmp(arg, "--textconv"))
3897                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3898        else if (!strcmp(arg, "--no-textconv"))
3899                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3900        else if (!strcmp(arg, "--ignore-submodules")) {
3901                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3902                handle_ignore_submodules_arg(options, "all");
3903        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3904                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3905                handle_ignore_submodules_arg(options, arg);
3906        } else if (!strcmp(arg, "--submodule"))
3907                DIFF_OPT_SET(options, SUBMODULE_LOG);
3908        else if (skip_prefix(arg, "--submodule=", &arg))
3909                return parse_submodule_opt(options, arg);
3910        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3911                return parse_ws_error_highlight(options, arg);
3912
3913        /* misc options */
3914        else if (!strcmp(arg, "-z"))
3915                options->line_termination = 0;
3916        else if ((argcount = short_opt('l', av, &optarg))) {
3917                options->rename_limit = strtoul(optarg, NULL, 10);
3918                return argcount;
3919        }
3920        else if ((argcount = short_opt('S', av, &optarg))) {
3921                options->pickaxe = optarg;
3922                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3923                return argcount;
3924        } else if ((argcount = short_opt('G', av, &optarg))) {
3925                options->pickaxe = optarg;
3926                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3927                return argcount;
3928        }
3929        else if (!strcmp(arg, "--pickaxe-all"))
3930                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3931        else if (!strcmp(arg, "--pickaxe-regex"))
3932                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3933        else if ((argcount = short_opt('O', av, &optarg))) {
3934                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3935                options->orderfile = xstrdup(path);
3936                return argcount;
3937        }
3938        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3939                int offending = parse_diff_filter_opt(optarg, options);
3940                if (offending)
3941                        die("unknown change class '%c' in --diff-filter=%s",
3942                            offending, optarg);
3943                return argcount;
3944        }
3945        else if (!strcmp(arg, "--abbrev"))
3946                options->abbrev = DEFAULT_ABBREV;
3947        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3948                options->abbrev = strtoul(arg, NULL, 10);
3949                if (options->abbrev < MINIMUM_ABBREV)
3950                        options->abbrev = MINIMUM_ABBREV;
3951                else if (40 < options->abbrev)
3952                        options->abbrev = 40;
3953        }
3954        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3955                options->a_prefix = optarg;
3956                return argcount;
3957        }
3958        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3959                options->b_prefix = optarg;
3960                return argcount;
3961        }
3962        else if (!strcmp(arg, "--no-prefix"))
3963                options->a_prefix = options->b_prefix = "";
3964        else if (opt_arg(arg, '\0', "inter-hunk-context",
3965                         &options->interhunkcontext))
3966                ;
3967        else if (!strcmp(arg, "-W"))
3968                DIFF_OPT_SET(options, FUNCCONTEXT);
3969        else if (!strcmp(arg, "--function-context"))
3970                DIFF_OPT_SET(options, FUNCCONTEXT);
3971        else if (!strcmp(arg, "--no-function-context"))
3972                DIFF_OPT_CLR(options, FUNCCONTEXT);
3973        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3974                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3975                options->file = fopen(path, "w");
3976                if (!options->file)
3977                        die_errno("Could not open '%s'", path);
3978                options->close_file = 1;
3979                if (options->use_color != GIT_COLOR_ALWAYS)
3980                        options->use_color = GIT_COLOR_NEVER;
3981                return argcount;
3982        } else
3983                return 0;
3984        return 1;
3985}
3986
3987int parse_rename_score(const char **cp_p)
3988{
3989        unsigned long num, scale;
3990        int ch, dot;
3991        const char *cp = *cp_p;
3992
3993        num = 0;
3994        scale = 1;
3995        dot = 0;
3996        for (;;) {
3997                ch = *cp;
3998                if ( !dot && ch == '.' ) {
3999                        scale = 1;
4000                        dot = 1;
4001                } else if ( ch == '%' ) {
4002                        scale = dot ? scale*100 : 100;
4003                        cp++;   /* % is always at the end */
4004                        break;
4005                } else if ( ch >= '0' && ch <= '9' ) {
4006                        if ( scale < 100000 ) {
4007                                scale *= 10;
4008                                num = (num*10) + (ch-'0');
4009                        }
4010                } else {
4011                        break;
4012                }
4013                cp++;
4014        }
4015        *cp_p = cp;
4016
4017        /* user says num divided by scale and we say internally that
4018         * is MAX_SCORE * num / scale.
4019         */
4020        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4021}
4022
4023static int diff_scoreopt_parse(const char *opt)
4024{
4025        int opt1, opt2, cmd;
4026
4027        if (*opt++ != '-')
4028                return -1;
4029        cmd = *opt++;
4030        if (cmd == '-') {
4031                /* convert the long-form arguments into short-form versions */
4032                if (skip_prefix(opt, "break-rewrites", &opt)) {
4033                        if (*opt == 0 || *opt++ == '=')
4034                                cmd = 'B';
4035                } else if (skip_prefix(opt, "find-copies", &opt)) {
4036                        if (*opt == 0 || *opt++ == '=')
4037                                cmd = 'C';
4038                } else if (skip_prefix(opt, "find-renames", &opt)) {
4039                        if (*opt == 0 || *opt++ == '=')
4040                                cmd = 'M';
4041                }
4042        }
4043        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4044                return -1; /* that is not a -M, -C, or -B option */
4045
4046        opt1 = parse_rename_score(&opt);
4047        if (cmd != 'B')
4048                opt2 = 0;
4049        else {
4050                if (*opt == 0)
4051                        opt2 = 0;
4052                else if (*opt != '/')
4053                        return -1; /* we expect -B80/99 or -B80 */
4054                else {
4055                        opt++;
4056                        opt2 = parse_rename_score(&opt);
4057                }
4058        }
4059        if (*opt != 0)
4060                return -1;
4061        return opt1 | (opt2 << 16);
4062}
4063
4064struct diff_queue_struct diff_queued_diff;
4065
4066void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4067{
4068        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4069        queue->queue[queue->nr++] = dp;
4070}
4071
4072struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4073                                 struct diff_filespec *one,
4074                                 struct diff_filespec *two)
4075{
4076        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4077        dp->one = one;
4078        dp->two = two;
4079        if (queue)
4080                diff_q(queue, dp);
4081        return dp;
4082}
4083
4084void diff_free_filepair(struct diff_filepair *p)
4085{
4086        free_filespec(p->one);
4087        free_filespec(p->two);
4088        free(p);
4089}
4090
4091/* This is different from find_unique_abbrev() in that
4092 * it stuffs the result with dots for alignment.
4093 */
4094const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4095{
4096        int abblen;
4097        const char *abbrev;
4098        if (len == 40)
4099                return sha1_to_hex(sha1);
4100
4101        abbrev = find_unique_abbrev(sha1, len);
4102        abblen = strlen(abbrev);
4103        if (abblen < 37) {
4104                static char hex[41];
4105                if (len < abblen && abblen <= len + 2)
4106                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4107                else
4108                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4109                return hex;
4110        }
4111        return sha1_to_hex(sha1);
4112}
4113
4114static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4115{
4116        int line_termination = opt->line_termination;
4117        int inter_name_termination = line_termination ? '\t' : '\0';
4118
4119        fprintf(opt->file, "%s", diff_line_prefix(opt));
4120        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4121                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4122                        diff_unique_abbrev(p->one->oid.hash, opt->abbrev));
4123                fprintf(opt->file, "%s ",
4124                        diff_unique_abbrev(p->two->oid.hash, opt->abbrev));
4125        }
4126        if (p->score) {
4127                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4128                        inter_name_termination);
4129        } else {
4130                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4131        }
4132
4133        if (p->status == DIFF_STATUS_COPIED ||
4134            p->status == DIFF_STATUS_RENAMED) {
4135                const char *name_a, *name_b;
4136                name_a = p->one->path;
4137                name_b = p->two->path;
4138                strip_prefix(opt->prefix_length, &name_a, &name_b);
4139                write_name_quoted(name_a, opt->file, inter_name_termination);
4140                write_name_quoted(name_b, opt->file, line_termination);
4141        } else {
4142                const char *name_a, *name_b;
4143                name_a = p->one->mode ? p->one->path : p->two->path;
4144                name_b = NULL;
4145                strip_prefix(opt->prefix_length, &name_a, &name_b);
4146                write_name_quoted(name_a, opt->file, line_termination);
4147        }
4148}
4149
4150int diff_unmodified_pair(struct diff_filepair *p)
4151{
4152        /* This function is written stricter than necessary to support
4153         * the currently implemented transformers, but the idea is to
4154         * let transformers to produce diff_filepairs any way they want,
4155         * and filter and clean them up here before producing the output.
4156         */
4157        struct diff_filespec *one = p->one, *two = p->two;
4158
4159        if (DIFF_PAIR_UNMERGED(p))
4160                return 0; /* unmerged is interesting */
4161
4162        /* deletion, addition, mode or type change
4163         * and rename are all interesting.
4164         */
4165        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4166            DIFF_PAIR_MODE_CHANGED(p) ||
4167            strcmp(one->path, two->path))
4168                return 0;
4169
4170        /* both are valid and point at the same path.  that is, we are
4171         * dealing with a change.
4172         */
4173        if (one->oid_valid && two->oid_valid &&
4174            !oidcmp(&one->oid, &two->oid) &&
4175            !one->dirty_submodule && !two->dirty_submodule)
4176                return 1; /* no change */
4177        if (!one->oid_valid && !two->oid_valid)
4178                return 1; /* both look at the same file on the filesystem. */
4179        return 0;
4180}
4181
4182static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4183{
4184        if (diff_unmodified_pair(p))
4185                return;
4186
4187        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4188            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4189                return; /* no tree diffs in patch format */
4190
4191        run_diff(p, o);
4192}
4193
4194static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4195                            struct diffstat_t *diffstat)
4196{
4197        if (diff_unmodified_pair(p))
4198                return;
4199
4200        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4201            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4202                return; /* no useful stat for tree diffs */
4203
4204        run_diffstat(p, o, diffstat);
4205}
4206
4207static void diff_flush_checkdiff(struct diff_filepair *p,
4208                struct diff_options *o)
4209{
4210        if (diff_unmodified_pair(p))
4211                return;
4212
4213        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4214            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4215                return; /* nothing to check in tree diffs */
4216
4217        run_checkdiff(p, o);
4218}
4219
4220int diff_queue_is_empty(void)
4221{
4222        struct diff_queue_struct *q = &diff_queued_diff;
4223        int i;
4224        for (i = 0; i < q->nr; i++)
4225                if (!diff_unmodified_pair(q->queue[i]))
4226                        return 0;
4227        return 1;
4228}
4229
4230#if DIFF_DEBUG
4231void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4232{
4233        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4234                x, one ? one : "",
4235                s->path,
4236                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4237                s->mode,
4238                s->oid_valid ? oid_to_hex(&s->oid) : "");
4239        fprintf(stderr, "queue[%d] %s size %lu\n",
4240                x, one ? one : "",
4241                s->size);
4242}
4243
4244void diff_debug_filepair(const struct diff_filepair *p, int i)
4245{
4246        diff_debug_filespec(p->one, i, "one");
4247        diff_debug_filespec(p->two, i, "two");
4248        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4249                p->score, p->status ? p->status : '?',
4250                p->one->rename_used, p->broken_pair);
4251}
4252
4253void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4254{
4255        int i;
4256        if (msg)
4257                fprintf(stderr, "%s\n", msg);
4258        fprintf(stderr, "q->nr = %d\n", q->nr);
4259        for (i = 0; i < q->nr; i++) {
4260                struct diff_filepair *p = q->queue[i];
4261                diff_debug_filepair(p, i);
4262        }
4263}
4264#endif
4265
4266static void diff_resolve_rename_copy(void)
4267{
4268        int i;
4269        struct diff_filepair *p;
4270        struct diff_queue_struct *q = &diff_queued_diff;
4271
4272        diff_debug_queue("resolve-rename-copy", q);
4273
4274        for (i = 0; i < q->nr; i++) {
4275                p = q->queue[i];
4276                p->status = 0; /* undecided */
4277                if (DIFF_PAIR_UNMERGED(p))
4278                        p->status = DIFF_STATUS_UNMERGED;
4279                else if (!DIFF_FILE_VALID(p->one))
4280                        p->status = DIFF_STATUS_ADDED;
4281                else if (!DIFF_FILE_VALID(p->two))
4282                        p->status = DIFF_STATUS_DELETED;
4283                else if (DIFF_PAIR_TYPE_CHANGED(p))
4284                        p->status = DIFF_STATUS_TYPE_CHANGED;
4285
4286                /* from this point on, we are dealing with a pair
4287                 * whose both sides are valid and of the same type, i.e.
4288                 * either in-place edit or rename/copy edit.
4289                 */
4290                else if (DIFF_PAIR_RENAME(p)) {
4291                        /*
4292                         * A rename might have re-connected a broken
4293                         * pair up, causing the pathnames to be the
4294                         * same again. If so, that's not a rename at
4295                         * all, just a modification..
4296                         *
4297                         * Otherwise, see if this source was used for
4298                         * multiple renames, in which case we decrement
4299                         * the count, and call it a copy.
4300                         */
4301                        if (!strcmp(p->one->path, p->two->path))
4302                                p->status = DIFF_STATUS_MODIFIED;
4303                        else if (--p->one->rename_used > 0)
4304                                p->status = DIFF_STATUS_COPIED;
4305                        else
4306                                p->status = DIFF_STATUS_RENAMED;
4307                }
4308                else if (oidcmp(&p->one->oid, &p->two->oid) ||
4309                         p->one->mode != p->two->mode ||
4310                         p->one->dirty_submodule ||
4311                         p->two->dirty_submodule ||
4312                         is_null_oid(&p->one->oid))
4313                        p->status = DIFF_STATUS_MODIFIED;
4314                else {
4315                        /* This is a "no-change" entry and should not
4316                         * happen anymore, but prepare for broken callers.
4317                         */
4318                        error("feeding unmodified %s to diffcore",
4319                              p->one->path);
4320                        p->status = DIFF_STATUS_UNKNOWN;
4321                }
4322        }
4323        diff_debug_queue("resolve-rename-copy done", q);
4324}
4325
4326static int check_pair_status(struct diff_filepair *p)
4327{
4328        switch (p->status) {
4329        case DIFF_STATUS_UNKNOWN:
4330                return 0;
4331        case 0:
4332                die("internal error in diff-resolve-rename-copy");
4333        default:
4334                return 1;
4335        }
4336}
4337
4338static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4339{
4340        int fmt = opt->output_format;
4341
4342        if (fmt & DIFF_FORMAT_CHECKDIFF)
4343                diff_flush_checkdiff(p, opt);
4344        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4345                diff_flush_raw(p, opt);
4346        else if (fmt & DIFF_FORMAT_NAME) {
4347                const char *name_a, *name_b;
4348                name_a = p->two->path;
4349                name_b = NULL;
4350                strip_prefix(opt->prefix_length, &name_a, &name_b);
4351                write_name_quoted(name_a, opt->file, opt->line_termination);
4352        }
4353}
4354
4355static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4356{
4357        if (fs->mode)
4358                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4359        else
4360                fprintf(file, " %s ", newdelete);
4361        write_name_quoted(fs->path, file, '\n');
4362}
4363
4364
4365static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4366                const char *line_prefix)
4367{
4368        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4369                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4370                        p->two->mode, show_name ? ' ' : '\n');
4371                if (show_name) {
4372                        write_name_quoted(p->two->path, file, '\n');
4373                }
4374        }
4375}
4376
4377static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4378                        const char *line_prefix)
4379{
4380        char *names = pprint_rename(p->one->path, p->two->path);
4381
4382        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4383        free(names);
4384        show_mode_change(file, p, 0, line_prefix);
4385}
4386
4387static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4388{
4389        FILE *file = opt->file;
4390        const char *line_prefix = diff_line_prefix(opt);
4391
4392        switch(p->status) {
4393        case DIFF_STATUS_DELETED:
4394                fputs(line_prefix, file);
4395                show_file_mode_name(file, "delete", p->one);
4396                break;
4397        case DIFF_STATUS_ADDED:
4398                fputs(line_prefix, file);
4399                show_file_mode_name(file, "create", p->two);
4400                break;
4401        case DIFF_STATUS_COPIED:
4402                fputs(line_prefix, file);
4403                show_rename_copy(file, "copy", p, line_prefix);
4404                break;
4405        case DIFF_STATUS_RENAMED:
4406                fputs(line_prefix, file);
4407                show_rename_copy(file, "rename", p, line_prefix);
4408                break;
4409        default:
4410                if (p->score) {
4411                        fprintf(file, "%s rewrite ", line_prefix);
4412                        write_name_quoted(p->two->path, file, ' ');
4413                        fprintf(file, "(%d%%)\n", similarity_index(p));
4414                }
4415                show_mode_change(file, p, !p->score, line_prefix);
4416                break;
4417        }
4418}
4419
4420struct patch_id_t {
4421        git_SHA_CTX *ctx;
4422        int patchlen;
4423};
4424
4425static int remove_space(char *line, int len)
4426{
4427        int i;
4428        char *dst = line;
4429        unsigned char c;
4430
4431        for (i = 0; i < len; i++)
4432                if (!isspace((c = line[i])))
4433                        *dst++ = c;
4434
4435        return dst - line;
4436}
4437
4438static void patch_id_consume(void *priv, char *line, unsigned long len)
4439{
4440        struct patch_id_t *data = priv;
4441        int new_len;
4442
4443        /* Ignore line numbers when computing the SHA1 of the patch */
4444        if (starts_with(line, "@@ -"))
4445                return;
4446
4447        new_len = remove_space(line, len);
4448
4449        git_SHA1_Update(data->ctx, line, new_len);
4450        data->patchlen += new_len;
4451}
4452
4453/* returns 0 upon success, and writes result into sha1 */
4454static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4455{
4456        struct diff_queue_struct *q = &diff_queued_diff;
4457        int i;
4458        git_SHA_CTX ctx;
4459        struct patch_id_t data;
4460        char buffer[PATH_MAX * 4 + 20];
4461
4462        git_SHA1_Init(&ctx);
4463        memset(&data, 0, sizeof(struct patch_id_t));
4464        data.ctx = &ctx;
4465
4466        for (i = 0; i < q->nr; i++) {
4467                xpparam_t xpp;
4468                xdemitconf_t xecfg;
4469                mmfile_t mf1, mf2;
4470                struct diff_filepair *p = q->queue[i];
4471                int len1, len2;
4472
4473                memset(&xpp, 0, sizeof(xpp));
4474                memset(&xecfg, 0, sizeof(xecfg));
4475                if (p->status == 0)
4476                        return error("internal diff status error");
4477                if (p->status == DIFF_STATUS_UNKNOWN)
4478                        continue;
4479                if (diff_unmodified_pair(p))
4480                        continue;
4481                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4482                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4483                        continue;
4484                if (DIFF_PAIR_UNMERGED(p))
4485                        continue;
4486
4487                diff_fill_sha1_info(p->one);
4488                diff_fill_sha1_info(p->two);
4489
4490                len1 = remove_space(p->one->path, strlen(p->one->path));
4491                len2 = remove_space(p->two->path, strlen(p->two->path));
4492                if (p->one->mode == 0)
4493                        len1 = snprintf(buffer, sizeof(buffer),
4494                                        "diff--gita/%.*sb/%.*s"
4495                                        "newfilemode%06o"
4496                                        "---/dev/null"
4497                                        "+++b/%.*s",
4498                                        len1, p->one->path,
4499                                        len2, p->two->path,
4500                                        p->two->mode,
4501                                        len2, p->two->path);
4502                else if (p->two->mode == 0)
4503                        len1 = snprintf(buffer, sizeof(buffer),
4504                                        "diff--gita/%.*sb/%.*s"
4505                                        "deletedfilemode%06o"
4506                                        "---a/%.*s"
4507                                        "+++/dev/null",
4508                                        len1, p->one->path,
4509                                        len2, p->two->path,
4510                                        p->one->mode,
4511                                        len1, p->one->path);
4512                else
4513                        len1 = snprintf(buffer, sizeof(buffer),
4514                                        "diff--gita/%.*sb/%.*s"
4515                                        "---a/%.*s"
4516                                        "+++b/%.*s",
4517                                        len1, p->one->path,
4518                                        len2, p->two->path,
4519                                        len1, p->one->path,
4520                                        len2, p->two->path);
4521                git_SHA1_Update(&ctx, buffer, len1);
4522
4523                if (diff_header_only)
4524                        continue;
4525
4526                if (fill_mmfile(&mf1, p->one) < 0 ||
4527                    fill_mmfile(&mf2, p->two) < 0)
4528                        return error("unable to read files to diff");
4529
4530                if (diff_filespec_is_binary(p->one) ||
4531                    diff_filespec_is_binary(p->two)) {
4532                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4533                                        40);
4534                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4535                                        40);
4536                        continue;
4537                }
4538
4539                xpp.flags = 0;
4540                xecfg.ctxlen = 3;
4541                xecfg.flags = 0;
4542                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4543                                  &xpp, &xecfg))
4544                        return error("unable to generate patch-id diff for %s",
4545                                     p->one->path);
4546        }
4547
4548        git_SHA1_Final(sha1, &ctx);
4549        return 0;
4550}
4551
4552int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4553{
4554        struct diff_queue_struct *q = &diff_queued_diff;
4555        int i;
4556        int result = diff_get_patch_id(options, sha1, diff_header_only);
4557
4558        for (i = 0; i < q->nr; i++)
4559                diff_free_filepair(q->queue[i]);
4560
4561        free(q->queue);
4562        DIFF_QUEUE_CLEAR(q);
4563
4564        return result;
4565}
4566
4567static int is_summary_empty(const struct diff_queue_struct *q)
4568{
4569        int i;
4570
4571        for (i = 0; i < q->nr; i++) {
4572                const struct diff_filepair *p = q->queue[i];
4573
4574                switch (p->status) {
4575                case DIFF_STATUS_DELETED:
4576                case DIFF_STATUS_ADDED:
4577                case DIFF_STATUS_COPIED:
4578                case DIFF_STATUS_RENAMED:
4579                        return 0;
4580                default:
4581                        if (p->score)
4582                                return 0;
4583                        if (p->one->mode && p->two->mode &&
4584                            p->one->mode != p->two->mode)
4585                                return 0;
4586                        break;
4587                }
4588        }
4589        return 1;
4590}
4591
4592static const char rename_limit_warning[] =
4593"inexact rename detection was skipped due to too many files.";
4594
4595static const char degrade_cc_to_c_warning[] =
4596"only found copies from modified paths due to too many files.";
4597
4598static const char rename_limit_advice[] =
4599"you may want to set your %s variable to at least "
4600"%d and retry the command.";
4601
4602void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4603{
4604        if (degraded_cc)
4605                warning(degrade_cc_to_c_warning);
4606        else if (needed)
4607                warning(rename_limit_warning);
4608        else
4609                return;
4610        if (0 < needed && needed < 32767)
4611                warning(rename_limit_advice, varname, needed);
4612}
4613
4614void diff_flush(struct diff_options *options)
4615{
4616        struct diff_queue_struct *q = &diff_queued_diff;
4617        int i, output_format = options->output_format;
4618        int separator = 0;
4619        int dirstat_by_line = 0;
4620
4621        /*
4622         * Order: raw, stat, summary, patch
4623         * or:    name/name-status/checkdiff (other bits clear)
4624         */
4625        if (!q->nr)
4626                goto free_queue;
4627
4628        if (output_format & (DIFF_FORMAT_RAW |
4629                             DIFF_FORMAT_NAME |
4630                             DIFF_FORMAT_NAME_STATUS |
4631                             DIFF_FORMAT_CHECKDIFF)) {
4632                for (i = 0; i < q->nr; i++) {
4633                        struct diff_filepair *p = q->queue[i];
4634                        if (check_pair_status(p))
4635                                flush_one_pair(p, options);
4636                }
4637                separator++;
4638        }
4639
4640        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4641                dirstat_by_line = 1;
4642
4643        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4644            dirstat_by_line) {
4645                struct diffstat_t diffstat;
4646
4647                memset(&diffstat, 0, sizeof(struct diffstat_t));
4648                for (i = 0; i < q->nr; i++) {
4649                        struct diff_filepair *p = q->queue[i];
4650                        if (check_pair_status(p))
4651                                diff_flush_stat(p, options, &diffstat);
4652                }
4653                if (output_format & DIFF_FORMAT_NUMSTAT)
4654                        show_numstat(&diffstat, options);
4655                if (output_format & DIFF_FORMAT_DIFFSTAT)
4656                        show_stats(&diffstat, options);
4657                if (output_format & DIFF_FORMAT_SHORTSTAT)
4658                        show_shortstats(&diffstat, options);
4659                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4660                        show_dirstat_by_line(&diffstat, options);
4661                free_diffstat_info(&diffstat);
4662                separator++;
4663        }
4664        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4665                show_dirstat(options);
4666
4667        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4668                for (i = 0; i < q->nr; i++) {
4669                        diff_summary(options, q->queue[i]);
4670                }
4671                separator++;
4672        }
4673
4674        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4675            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4676            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4677                /*
4678                 * run diff_flush_patch for the exit status. setting
4679                 * options->file to /dev/null should be safe, because we
4680                 * aren't supposed to produce any output anyway.
4681                 */
4682                if (options->close_file)
4683                        fclose(options->file);
4684                options->file = fopen("/dev/null", "w");
4685                if (!options->file)
4686                        die_errno("Could not open /dev/null");
4687                options->close_file = 1;
4688                for (i = 0; i < q->nr; i++) {
4689                        struct diff_filepair *p = q->queue[i];
4690                        if (check_pair_status(p))
4691                                diff_flush_patch(p, options);
4692                        if (options->found_changes)
4693                                break;
4694                }
4695        }
4696
4697        if (output_format & DIFF_FORMAT_PATCH) {
4698                if (separator) {
4699                        fprintf(options->file, "%s%c",
4700                                diff_line_prefix(options),
4701                                options->line_termination);
4702                        if (options->stat_sep) {
4703                                /* attach patch instead of inline */
4704                                fputs(options->stat_sep, options->file);
4705                        }
4706                }
4707
4708                for (i = 0; i < q->nr; i++) {
4709                        struct diff_filepair *p = q->queue[i];
4710                        if (check_pair_status(p))
4711                                diff_flush_patch(p, options);
4712                }
4713        }
4714
4715        if (output_format & DIFF_FORMAT_CALLBACK)
4716                options->format_callback(q, options, options->format_callback_data);
4717
4718        for (i = 0; i < q->nr; i++)
4719                diff_free_filepair(q->queue[i]);
4720free_queue:
4721        free(q->queue);
4722        DIFF_QUEUE_CLEAR(q);
4723        if (options->close_file)
4724                fclose(options->file);
4725
4726        /*
4727         * Report the content-level differences with HAS_CHANGES;
4728         * diff_addremove/diff_change does not set the bit when
4729         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4730         */
4731        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4732                if (options->found_changes)
4733                        DIFF_OPT_SET(options, HAS_CHANGES);
4734                else
4735                        DIFF_OPT_CLR(options, HAS_CHANGES);
4736        }
4737}
4738
4739static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4740{
4741        return (((p->status == DIFF_STATUS_MODIFIED) &&
4742                 ((p->score &&
4743                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4744                  (!p->score &&
4745                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4746                ((p->status != DIFF_STATUS_MODIFIED) &&
4747                 filter_bit_tst(p->status, options)));
4748}
4749
4750static void diffcore_apply_filter(struct diff_options *options)
4751{
4752        int i;
4753        struct diff_queue_struct *q = &diff_queued_diff;
4754        struct diff_queue_struct outq;
4755
4756        DIFF_QUEUE_CLEAR(&outq);
4757
4758        if (!options->filter)
4759                return;
4760
4761        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4762                int found;
4763                for (i = found = 0; !found && i < q->nr; i++) {
4764                        if (match_filter(options, q->queue[i]))
4765                                found++;
4766                }
4767                if (found)
4768                        return;
4769
4770                /* otherwise we will clear the whole queue
4771                 * by copying the empty outq at the end of this
4772                 * function, but first clear the current entries
4773                 * in the queue.
4774                 */
4775                for (i = 0; i < q->nr; i++)
4776                        diff_free_filepair(q->queue[i]);
4777        }
4778        else {
4779                /* Only the matching ones */
4780                for (i = 0; i < q->nr; i++) {
4781                        struct diff_filepair *p = q->queue[i];
4782                        if (match_filter(options, p))
4783                                diff_q(&outq, p);
4784                        else
4785                                diff_free_filepair(p);
4786                }
4787        }
4788        free(q->queue);
4789        *q = outq;
4790}
4791
4792/* Check whether two filespecs with the same mode and size are identical */
4793static int diff_filespec_is_identical(struct diff_filespec *one,
4794                                      struct diff_filespec *two)
4795{
4796        if (S_ISGITLINK(one->mode))
4797                return 0;
4798        if (diff_populate_filespec(one, 0))
4799                return 0;
4800        if (diff_populate_filespec(two, 0))
4801                return 0;
4802        return !memcmp(one->data, two->data, one->size);
4803}
4804
4805static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4806{
4807        if (p->done_skip_stat_unmatch)
4808                return p->skip_stat_unmatch_result;
4809
4810        p->done_skip_stat_unmatch = 1;
4811        p->skip_stat_unmatch_result = 0;
4812        /*
4813         * 1. Entries that come from stat info dirtiness
4814         *    always have both sides (iow, not create/delete),
4815         *    one side of the object name is unknown, with
4816         *    the same mode and size.  Keep the ones that
4817         *    do not match these criteria.  They have real
4818         *    differences.
4819         *
4820         * 2. At this point, the file is known to be modified,
4821         *    with the same mode and size, and the object
4822         *    name of one side is unknown.  Need to inspect
4823         *    the identical contents.
4824         */
4825        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4826            !DIFF_FILE_VALID(p->two) ||
4827            (p->one->oid_valid && p->two->oid_valid) ||
4828            (p->one->mode != p->two->mode) ||
4829            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4830            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4831            (p->one->size != p->two->size) ||
4832            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4833                p->skip_stat_unmatch_result = 1;
4834        return p->skip_stat_unmatch_result;
4835}
4836
4837static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4838{
4839        int i;
4840        struct diff_queue_struct *q = &diff_queued_diff;
4841        struct diff_queue_struct outq;
4842        DIFF_QUEUE_CLEAR(&outq);
4843
4844        for (i = 0; i < q->nr; i++) {
4845                struct diff_filepair *p = q->queue[i];
4846
4847                if (diff_filespec_check_stat_unmatch(p))
4848                        diff_q(&outq, p);
4849                else {
4850                        /*
4851                         * The caller can subtract 1 from skip_stat_unmatch
4852                         * to determine how many paths were dirty only
4853                         * due to stat info mismatch.
4854                         */
4855                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4856                                diffopt->skip_stat_unmatch++;
4857                        diff_free_filepair(p);
4858                }
4859        }
4860        free(q->queue);
4861        *q = outq;
4862}
4863
4864static int diffnamecmp(const void *a_, const void *b_)
4865{
4866        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4867        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4868        const char *name_a, *name_b;
4869
4870        name_a = a->one ? a->one->path : a->two->path;
4871        name_b = b->one ? b->one->path : b->two->path;
4872        return strcmp(name_a, name_b);
4873}
4874
4875void diffcore_fix_diff_index(struct diff_options *options)
4876{
4877        struct diff_queue_struct *q = &diff_queued_diff;
4878        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4879}
4880
4881void diffcore_std(struct diff_options *options)
4882{
4883        /* NOTE please keep the following in sync with diff_tree_combined() */
4884        if (options->skip_stat_unmatch)
4885                diffcore_skip_stat_unmatch(options);
4886        if (!options->found_follow) {
4887                /* See try_to_follow_renames() in tree-diff.c */
4888                if (options->break_opt != -1)
4889                        diffcore_break(options->break_opt);
4890                if (options->detect_rename)
4891                        diffcore_rename(options);
4892                if (options->break_opt != -1)
4893                        diffcore_merge_broken();
4894        }
4895        if (options->pickaxe)
4896                diffcore_pickaxe(options);
4897        if (options->orderfile)
4898                diffcore_order(options->orderfile);
4899        if (!options->found_follow)
4900                /* See try_to_follow_renames() in tree-diff.c */
4901                diff_resolve_rename_copy();
4902        diffcore_apply_filter(options);
4903
4904        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4905                DIFF_OPT_SET(options, HAS_CHANGES);
4906        else
4907                DIFF_OPT_CLR(options, HAS_CHANGES);
4908
4909        options->found_follow = 0;
4910}
4911
4912int diff_result_code(struct diff_options *opt, int status)
4913{
4914        int result = 0;
4915
4916        diff_warn_rename_limit("diff.renameLimit",
4917                               opt->needed_rename_limit,
4918                               opt->degraded_cc_to_c);
4919        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4920            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4921                return status;
4922        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4923            DIFF_OPT_TST(opt, HAS_CHANGES))
4924                result |= 01;
4925        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4926            DIFF_OPT_TST(opt, CHECK_FAILED))
4927                result |= 02;
4928        return result;
4929}
4930
4931int diff_can_quit_early(struct diff_options *opt)
4932{
4933        return (DIFF_OPT_TST(opt, QUICK) &&
4934                !opt->filter &&
4935                DIFF_OPT_TST(opt, HAS_CHANGES));
4936}
4937
4938/*
4939 * Shall changes to this submodule be ignored?
4940 *
4941 * Submodule changes can be configured to be ignored separately for each path,
4942 * but that configuration can be overridden from the command line.
4943 */
4944static int is_submodule_ignored(const char *path, struct diff_options *options)
4945{
4946        int ignored = 0;
4947        unsigned orig_flags = options->flags;
4948        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4949                set_diffopt_flags_from_submodule_config(options, path);
4950        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4951                ignored = 1;
4952        options->flags = orig_flags;
4953        return ignored;
4954}
4955
4956void diff_addremove(struct diff_options *options,
4957                    int addremove, unsigned mode,
4958                    const unsigned char *sha1,
4959                    int sha1_valid,
4960                    const char *concatpath, unsigned dirty_submodule)
4961{
4962        struct diff_filespec *one, *two;
4963
4964        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4965                return;
4966
4967        /* This may look odd, but it is a preparation for
4968         * feeding "there are unchanged files which should
4969         * not produce diffs, but when you are doing copy
4970         * detection you would need them, so here they are"
4971         * entries to the diff-core.  They will be prefixed
4972         * with something like '=' or '*' (I haven't decided
4973         * which but should not make any difference).
4974         * Feeding the same new and old to diff_change()
4975         * also has the same effect.
4976         * Before the final output happens, they are pruned after
4977         * merged into rename/copy pairs as appropriate.
4978         */
4979        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4980                addremove = (addremove == '+' ? '-' :
4981                             addremove == '-' ? '+' : addremove);
4982
4983        if (options->prefix &&
4984            strncmp(concatpath, options->prefix, options->prefix_length))
4985                return;
4986
4987        one = alloc_filespec(concatpath);
4988        two = alloc_filespec(concatpath);
4989
4990        if (addremove != '+')
4991                fill_filespec(one, sha1, sha1_valid, mode);
4992        if (addremove != '-') {
4993                fill_filespec(two, sha1, sha1_valid, mode);
4994                two->dirty_submodule = dirty_submodule;
4995        }
4996
4997        diff_queue(&diff_queued_diff, one, two);
4998        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4999                DIFF_OPT_SET(options, HAS_CHANGES);
5000}
5001
5002void diff_change(struct diff_options *options,
5003                 unsigned old_mode, unsigned new_mode,
5004                 const unsigned char *old_sha1,
5005                 const unsigned char *new_sha1,
5006                 int old_sha1_valid, int new_sha1_valid,
5007                 const char *concatpath,
5008                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5009{
5010        struct diff_filespec *one, *two;
5011        struct diff_filepair *p;
5012
5013        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5014            is_submodule_ignored(concatpath, options))
5015                return;
5016
5017        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5018                unsigned tmp;
5019                const unsigned char *tmp_c;
5020                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
5021                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
5022                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
5023                        new_sha1_valid = tmp;
5024                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
5025                        new_dirty_submodule = tmp;
5026        }
5027
5028        if (options->prefix &&
5029            strncmp(concatpath, options->prefix, options->prefix_length))
5030                return;
5031
5032        one = alloc_filespec(concatpath);
5033        two = alloc_filespec(concatpath);
5034        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5035        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5036        one->dirty_submodule = old_dirty_submodule;
5037        two->dirty_submodule = new_dirty_submodule;
5038        p = diff_queue(&diff_queued_diff, one, two);
5039
5040        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5041                return;
5042
5043        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5044            !diff_filespec_check_stat_unmatch(p))
5045                return;
5046
5047        DIFF_OPT_SET(options, HAS_CHANGES);
5048}
5049
5050struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5051{
5052        struct diff_filepair *pair;
5053        struct diff_filespec *one, *two;
5054
5055        if (options->prefix &&
5056            strncmp(path, options->prefix, options->prefix_length))
5057                return NULL;
5058
5059        one = alloc_filespec(path);
5060        two = alloc_filespec(path);
5061        pair = diff_queue(&diff_queued_diff, one, two);
5062        pair->is_unmerged = 1;
5063        return pair;
5064}
5065
5066static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5067                size_t *outsize)
5068{
5069        struct diff_tempfile *temp;
5070        const char *argv[3];
5071        const char **arg = argv;
5072        struct child_process child = CHILD_PROCESS_INIT;
5073        struct strbuf buf = STRBUF_INIT;
5074        int err = 0;
5075
5076        temp = prepare_temp_file(spec->path, spec);
5077        *arg++ = pgm;
5078        *arg++ = temp->name;
5079        *arg = NULL;
5080
5081        child.use_shell = 1;
5082        child.argv = argv;
5083        child.out = -1;
5084        if (start_command(&child)) {
5085                remove_tempfile();
5086                return NULL;
5087        }
5088
5089        if (strbuf_read(&buf, child.out, 0) < 0)
5090                err = error("error reading from textconv command '%s'", pgm);
5091        close(child.out);
5092
5093        if (finish_command(&child) || err) {
5094                strbuf_release(&buf);
5095                remove_tempfile();
5096                return NULL;
5097        }
5098        remove_tempfile();
5099
5100        return strbuf_detach(&buf, outsize);
5101}
5102
5103size_t fill_textconv(struct userdiff_driver *driver,
5104                     struct diff_filespec *df,
5105                     char **outbuf)
5106{
5107        size_t size;
5108
5109        if (!driver) {
5110                if (!DIFF_FILE_VALID(df)) {
5111                        *outbuf = "";
5112                        return 0;
5113                }
5114                if (diff_populate_filespec(df, 0))
5115                        die("unable to read files to diff");
5116                *outbuf = df->data;
5117                return df->size;
5118        }
5119
5120        if (!driver->textconv)
5121                die("BUG: fill_textconv called with non-textconv driver");
5122
5123        if (driver->textconv_cache && df->oid_valid) {
5124                *outbuf = notes_cache_get(driver->textconv_cache,
5125                                          df->oid.hash,
5126                                          &size);
5127                if (*outbuf)
5128                        return size;
5129        }
5130
5131        *outbuf = run_textconv(driver->textconv, df, &size);
5132        if (!*outbuf)
5133                die("unable to read files to diff");
5134
5135        if (driver->textconv_cache && df->oid_valid) {
5136                /* ignore errors, as we might be in a readonly repository */
5137                notes_cache_put(driver->textconv_cache, df->oid.hash, *outbuf,
5138                                size);
5139                /*
5140                 * we could save up changes and flush them all at the end,
5141                 * but we would need an extra call after all diffing is done.
5142                 * Since generating a cache entry is the slow path anyway,
5143                 * this extra overhead probably isn't a big deal.
5144                 */
5145                notes_cache_write(driver->textconv_cache);
5146        }
5147
5148        return size;
5149}
5150
5151void setup_diff_pager(struct diff_options *opt)
5152{
5153        /*
5154         * If the user asked for our exit code, then either they want --quiet
5155         * or --exit-code. We should definitely not bother with a pager in the
5156         * former case, as we will generate no output. Since we still properly
5157         * report our exit code even when a pager is run, we _could_ run a
5158         * pager with --exit-code. But since we have not done so historically,
5159         * and because it is easy to find people oneline advising "git diff
5160         * --exit-code" in hooks and other scripts, we do not do so.
5161         */
5162        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5163            check_pager_config("diff") != 0)
5164                setup_pager();
5165}