diff.con commit Merge branch 'po/fix-doc-merge-base-illustration' into maint (311811b)
   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_buf(word_regex, buffer->ptr + *begin,
 953                                 buffer->size - *begin, 1, match, 0)) {
 954                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 955                                        '\n', match[0].rm_eo - match[0].rm_so);
 956                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 957                        *begin += match[0].rm_so;
 958                        return *begin >= *end;
 959                }
 960                return -1;
 961        }
 962
 963        /* find the next word */
 964        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 965                (*begin)++;
 966        if (*begin >= buffer->size)
 967                return -1;
 968
 969        /* find the end of the word */
 970        *end = *begin + 1;
 971        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 972                (*end)++;
 973
 974        return 0;
 975}
 976
 977/*
 978 * This function splits the words in buffer->text, stores the list with
 979 * newline separator into out, and saves the offsets of the original words
 980 * in buffer->orig.
 981 */
 982static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 983                regex_t *word_regex)
 984{
 985        int i, j;
 986        long alloc = 0;
 987
 988        out->size = 0;
 989        out->ptr = NULL;
 990
 991        /* fake an empty "0th" word */
 992        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 993        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 994        buffer->orig_nr = 1;
 995
 996        for (i = 0; i < buffer->text.size; i++) {
 997                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 998                        return;
 999
1000                /* store original boundaries */
1001                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1002                                buffer->orig_alloc);
1003                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1004                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1005                buffer->orig_nr++;
1006
1007                /* store one word */
1008                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1009                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1010                out->ptr[out->size + j - i] = '\n';
1011                out->size += j - i + 1;
1012
1013                i = j - 1;
1014        }
1015}
1016
1017/* this executes the word diff on the accumulated buffers */
1018static void diff_words_show(struct diff_words_data *diff_words)
1019{
1020        xpparam_t xpp;
1021        xdemitconf_t xecfg;
1022        mmfile_t minus, plus;
1023        struct diff_words_style *style = diff_words->style;
1024
1025        struct diff_options *opt = diff_words->opt;
1026        const char *line_prefix;
1027
1028        assert(opt);
1029        line_prefix = diff_line_prefix(opt);
1030
1031        /* special case: only removal */
1032        if (!diff_words->plus.text.size) {
1033                fputs(line_prefix, diff_words->opt->file);
1034                fn_out_diff_words_write_helper(diff_words->opt->file,
1035                        &style->old, style->newline,
1036                        diff_words->minus.text.size,
1037                        diff_words->minus.text.ptr, line_prefix);
1038                diff_words->minus.text.size = 0;
1039                return;
1040        }
1041
1042        diff_words->current_plus = diff_words->plus.text.ptr;
1043        diff_words->last_minus = 0;
1044
1045        memset(&xpp, 0, sizeof(xpp));
1046        memset(&xecfg, 0, sizeof(xecfg));
1047        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1048        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1049        xpp.flags = 0;
1050        /* as only the hunk header will be parsed, we need a 0-context */
1051        xecfg.ctxlen = 0;
1052        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1053                          &xpp, &xecfg))
1054                die("unable to generate word diff");
1055        free(minus.ptr);
1056        free(plus.ptr);
1057        if (diff_words->current_plus != diff_words->plus.text.ptr +
1058                        diff_words->plus.text.size) {
1059                if (color_words_output_graph_prefix(diff_words))
1060                        fputs(line_prefix, diff_words->opt->file);
1061                fn_out_diff_words_write_helper(diff_words->opt->file,
1062                        &style->ctx, style->newline,
1063                        diff_words->plus.text.ptr + diff_words->plus.text.size
1064                        - diff_words->current_plus, diff_words->current_plus,
1065                        line_prefix);
1066        }
1067        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1068}
1069
1070/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1071static void diff_words_flush(struct emit_callback *ecbdata)
1072{
1073        if (ecbdata->diff_words->minus.text.size ||
1074            ecbdata->diff_words->plus.text.size)
1075                diff_words_show(ecbdata->diff_words);
1076}
1077
1078static void diff_filespec_load_driver(struct diff_filespec *one)
1079{
1080        /* Use already-loaded driver */
1081        if (one->driver)
1082                return;
1083
1084        if (S_ISREG(one->mode))
1085                one->driver = userdiff_find_by_path(one->path);
1086
1087        /* Fallback to default settings */
1088        if (!one->driver)
1089                one->driver = userdiff_find_by_name("default");
1090}
1091
1092static const char *userdiff_word_regex(struct diff_filespec *one)
1093{
1094        diff_filespec_load_driver(one);
1095        return one->driver->word_regex;
1096}
1097
1098static void init_diff_words_data(struct emit_callback *ecbdata,
1099                                 struct diff_options *orig_opts,
1100                                 struct diff_filespec *one,
1101                                 struct diff_filespec *two)
1102{
1103        int i;
1104        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1105        memcpy(o, orig_opts, sizeof(struct diff_options));
1106
1107        ecbdata->diff_words =
1108                xcalloc(1, sizeof(struct diff_words_data));
1109        ecbdata->diff_words->type = o->word_diff;
1110        ecbdata->diff_words->opt = o;
1111        if (!o->word_regex)
1112                o->word_regex = userdiff_word_regex(one);
1113        if (!o->word_regex)
1114                o->word_regex = userdiff_word_regex(two);
1115        if (!o->word_regex)
1116                o->word_regex = diff_word_regex_cfg;
1117        if (o->word_regex) {
1118                ecbdata->diff_words->word_regex = (regex_t *)
1119                        xmalloc(sizeof(regex_t));
1120                if (regcomp(ecbdata->diff_words->word_regex,
1121                            o->word_regex,
1122                            REG_EXTENDED | REG_NEWLINE))
1123                        die ("Invalid regular expression: %s",
1124                             o->word_regex);
1125        }
1126        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1127                if (o->word_diff == diff_words_styles[i].type) {
1128                        ecbdata->diff_words->style =
1129                                &diff_words_styles[i];
1130                        break;
1131                }
1132        }
1133        if (want_color(o->use_color)) {
1134                struct diff_words_style *st = ecbdata->diff_words->style;
1135                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1136                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1137                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1138        }
1139}
1140
1141static void free_diff_words_data(struct emit_callback *ecbdata)
1142{
1143        if (ecbdata->diff_words) {
1144                diff_words_flush(ecbdata);
1145                free (ecbdata->diff_words->opt);
1146                free (ecbdata->diff_words->minus.text.ptr);
1147                free (ecbdata->diff_words->minus.orig);
1148                free (ecbdata->diff_words->plus.text.ptr);
1149                free (ecbdata->diff_words->plus.orig);
1150                if (ecbdata->diff_words->word_regex) {
1151                        regfree(ecbdata->diff_words->word_regex);
1152                        free(ecbdata->diff_words->word_regex);
1153                }
1154                free(ecbdata->diff_words);
1155                ecbdata->diff_words = NULL;
1156        }
1157}
1158
1159const char *diff_get_color(int diff_use_color, enum color_diff ix)
1160{
1161        if (want_color(diff_use_color))
1162                return diff_colors[ix];
1163        return "";
1164}
1165
1166const char *diff_line_prefix(struct diff_options *opt)
1167{
1168        struct strbuf *msgbuf;
1169        if (!opt->output_prefix)
1170                return "";
1171
1172        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1173        return msgbuf->buf;
1174}
1175
1176static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1177{
1178        const char *cp;
1179        unsigned long allot;
1180        size_t l = len;
1181
1182        if (ecb->truncate)
1183                return ecb->truncate(line, len);
1184        cp = line;
1185        allot = l;
1186        while (0 < l) {
1187                (void) utf8_width(&cp, &l);
1188                if (!cp)
1189                        break; /* truncated in the middle? */
1190        }
1191        return allot - l;
1192}
1193
1194static void find_lno(const char *line, struct emit_callback *ecbdata)
1195{
1196        const char *p;
1197        ecbdata->lno_in_preimage = 0;
1198        ecbdata->lno_in_postimage = 0;
1199        p = strchr(line, '-');
1200        if (!p)
1201                return; /* cannot happen */
1202        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1203        p = strchr(p, '+');
1204        if (!p)
1205                return; /* cannot happen */
1206        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1207}
1208
1209static void fn_out_consume(void *priv, char *line, unsigned long len)
1210{
1211        struct emit_callback *ecbdata = priv;
1212        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1213        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1214        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1215        struct diff_options *o = ecbdata->opt;
1216        const char *line_prefix = diff_line_prefix(o);
1217
1218        o->found_changes = 1;
1219
1220        if (ecbdata->header) {
1221                fprintf(o->file, "%s", ecbdata->header->buf);
1222                strbuf_reset(ecbdata->header);
1223                ecbdata->header = NULL;
1224        }
1225
1226        if (ecbdata->label_path[0]) {
1227                const char *name_a_tab, *name_b_tab;
1228
1229                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1230                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1231
1232                fprintf(o->file, "%s%s--- %s%s%s\n",
1233                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1234                fprintf(o->file, "%s%s+++ %s%s%s\n",
1235                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1236                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1237        }
1238
1239        if (diff_suppress_blank_empty
1240            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1241                line[0] = '\n';
1242                len = 1;
1243        }
1244
1245        if (line[0] == '@') {
1246                if (ecbdata->diff_words)
1247                        diff_words_flush(ecbdata);
1248                len = sane_truncate_line(ecbdata, line, len);
1249                find_lno(line, ecbdata);
1250                emit_hunk_header(ecbdata, line, len);
1251                if (line[len-1] != '\n')
1252                        putc('\n', o->file);
1253                return;
1254        }
1255
1256        if (ecbdata->diff_words) {
1257                if (line[0] == '-') {
1258                        diff_words_append(line, len,
1259                                          &ecbdata->diff_words->minus);
1260                        return;
1261                } else if (line[0] == '+') {
1262                        diff_words_append(line, len,
1263                                          &ecbdata->diff_words->plus);
1264                        return;
1265                } else if (starts_with(line, "\\ ")) {
1266                        /*
1267                         * Eat the "no newline at eof" marker as if we
1268                         * saw a "+" or "-" line with nothing on it,
1269                         * and return without diff_words_flush() to
1270                         * defer processing. If this is the end of
1271                         * preimage, more "+" lines may come after it.
1272                         */
1273                        return;
1274                }
1275                diff_words_flush(ecbdata);
1276                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1277                        emit_line(o, context, reset, line, len);
1278                        fputs("~\n", o->file);
1279                } else {
1280                        /*
1281                         * Skip the prefix character, if any.  With
1282                         * diff_suppress_blank_empty, there may be
1283                         * none.
1284                         */
1285                        if (line[0] != '\n') {
1286                              line++;
1287                              len--;
1288                        }
1289                        emit_line(o, context, reset, line, len);
1290                }
1291                return;
1292        }
1293
1294        switch (line[0]) {
1295        case '+':
1296                ecbdata->lno_in_postimage++;
1297                emit_add_line(reset, ecbdata, line + 1, len - 1);
1298                break;
1299        case '-':
1300                ecbdata->lno_in_preimage++;
1301                emit_del_line(reset, ecbdata, line + 1, len - 1);
1302                break;
1303        case ' ':
1304                ecbdata->lno_in_postimage++;
1305                ecbdata->lno_in_preimage++;
1306                emit_context_line(reset, ecbdata, line + 1, len - 1);
1307                break;
1308        default:
1309                /* incomplete line at the end */
1310                ecbdata->lno_in_preimage++;
1311                emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1312                          reset, line, len);
1313                break;
1314        }
1315}
1316
1317static char *pprint_rename(const char *a, const char *b)
1318{
1319        const char *old = a;
1320        const char *new = b;
1321        struct strbuf name = STRBUF_INIT;
1322        int pfx_length, sfx_length;
1323        int pfx_adjust_for_slash;
1324        int len_a = strlen(a);
1325        int len_b = strlen(b);
1326        int a_midlen, b_midlen;
1327        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1328        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1329
1330        if (qlen_a || qlen_b) {
1331                quote_c_style(a, &name, NULL, 0);
1332                strbuf_addstr(&name, " => ");
1333                quote_c_style(b, &name, NULL, 0);
1334                return strbuf_detach(&name, NULL);
1335        }
1336
1337        /* Find common prefix */
1338        pfx_length = 0;
1339        while (*old && *new && *old == *new) {
1340                if (*old == '/')
1341                        pfx_length = old - a + 1;
1342                old++;
1343                new++;
1344        }
1345
1346        /* Find common suffix */
1347        old = a + len_a;
1348        new = b + len_b;
1349        sfx_length = 0;
1350        /*
1351         * If there is a common prefix, it must end in a slash.  In
1352         * that case we let this loop run 1 into the prefix to see the
1353         * same slash.
1354         *
1355         * If there is no common prefix, we cannot do this as it would
1356         * underrun the input strings.
1357         */
1358        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1359        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1360               b + pfx_length - pfx_adjust_for_slash <= new &&
1361               *old == *new) {
1362                if (*old == '/')
1363                        sfx_length = len_a - (old - a);
1364                old--;
1365                new--;
1366        }
1367
1368        /*
1369         * pfx{mid-a => mid-b}sfx
1370         * {pfx-a => pfx-b}sfx
1371         * pfx{sfx-a => sfx-b}
1372         * name-a => name-b
1373         */
1374        a_midlen = len_a - pfx_length - sfx_length;
1375        b_midlen = len_b - pfx_length - sfx_length;
1376        if (a_midlen < 0)
1377                a_midlen = 0;
1378        if (b_midlen < 0)
1379                b_midlen = 0;
1380
1381        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1382        if (pfx_length + sfx_length) {
1383                strbuf_add(&name, a, pfx_length);
1384                strbuf_addch(&name, '{');
1385        }
1386        strbuf_add(&name, a + pfx_length, a_midlen);
1387        strbuf_addstr(&name, " => ");
1388        strbuf_add(&name, b + pfx_length, b_midlen);
1389        if (pfx_length + sfx_length) {
1390                strbuf_addch(&name, '}');
1391                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1392        }
1393        return strbuf_detach(&name, NULL);
1394}
1395
1396struct diffstat_t {
1397        int nr;
1398        int alloc;
1399        struct diffstat_file {
1400                char *from_name;
1401                char *name;
1402                char *print_name;
1403                unsigned is_unmerged:1;
1404                unsigned is_binary:1;
1405                unsigned is_renamed:1;
1406                unsigned is_interesting:1;
1407                uintmax_t added, deleted;
1408        } **files;
1409};
1410
1411static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1412                                          const char *name_a,
1413                                          const char *name_b)
1414{
1415        struct diffstat_file *x;
1416        x = xcalloc(1, sizeof(*x));
1417        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1418        diffstat->files[diffstat->nr++] = x;
1419        if (name_b) {
1420                x->from_name = xstrdup(name_a);
1421                x->name = xstrdup(name_b);
1422                x->is_renamed = 1;
1423        }
1424        else {
1425                x->from_name = NULL;
1426                x->name = xstrdup(name_a);
1427        }
1428        return x;
1429}
1430
1431static void diffstat_consume(void *priv, char *line, unsigned long len)
1432{
1433        struct diffstat_t *diffstat = priv;
1434        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1435
1436        if (line[0] == '+')
1437                x->added++;
1438        else if (line[0] == '-')
1439                x->deleted++;
1440}
1441
1442const char mime_boundary_leader[] = "------------";
1443
1444static int scale_linear(int it, int width, int max_change)
1445{
1446        if (!it)
1447                return 0;
1448        /*
1449         * make sure that at least one '-' or '+' is printed if
1450         * there is any change to this path. The easiest way is to
1451         * scale linearly as if the alloted width is one column shorter
1452         * than it is, and then add 1 to the result.
1453         */
1454        return 1 + (it * (width - 1) / max_change);
1455}
1456
1457static void show_name(FILE *file,
1458                      const char *prefix, const char *name, int len)
1459{
1460        fprintf(file, " %s%-*s |", prefix, len, name);
1461}
1462
1463static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1464{
1465        if (cnt <= 0)
1466                return;
1467        fprintf(file, "%s", set);
1468        while (cnt--)
1469                putc(ch, file);
1470        fprintf(file, "%s", reset);
1471}
1472
1473static void fill_print_name(struct diffstat_file *file)
1474{
1475        char *pname;
1476
1477        if (file->print_name)
1478                return;
1479
1480        if (!file->is_renamed) {
1481                struct strbuf buf = STRBUF_INIT;
1482                if (quote_c_style(file->name, &buf, NULL, 0)) {
1483                        pname = strbuf_detach(&buf, NULL);
1484                } else {
1485                        pname = file->name;
1486                        strbuf_release(&buf);
1487                }
1488        } else {
1489                pname = pprint_rename(file->from_name, file->name);
1490        }
1491        file->print_name = pname;
1492}
1493
1494int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1495{
1496        struct strbuf sb = STRBUF_INIT;
1497        int ret;
1498
1499        if (!files) {
1500                assert(insertions == 0 && deletions == 0);
1501                return fprintf(fp, "%s\n", " 0 files changed");
1502        }
1503
1504        strbuf_addf(&sb,
1505                    (files == 1) ? " %d file changed" : " %d files changed",
1506                    files);
1507
1508        /*
1509         * For binary diff, the caller may want to print "x files
1510         * changed" with insertions == 0 && deletions == 0.
1511         *
1512         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1513         * is probably less confusing (i.e skip over "2 files changed
1514         * but nothing about added/removed lines? Is this a bug in Git?").
1515         */
1516        if (insertions || deletions == 0) {
1517                strbuf_addf(&sb,
1518                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1519                            insertions);
1520        }
1521
1522        if (deletions || insertions == 0) {
1523                strbuf_addf(&sb,
1524                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1525                            deletions);
1526        }
1527        strbuf_addch(&sb, '\n');
1528        ret = fputs(sb.buf, fp);
1529        strbuf_release(&sb);
1530        return ret;
1531}
1532
1533static void show_stats(struct diffstat_t *data, struct diff_options *options)
1534{
1535        int i, len, add, del, adds = 0, dels = 0;
1536        uintmax_t max_change = 0, max_len = 0;
1537        int total_files = data->nr, count;
1538        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1539        const char *reset, *add_c, *del_c;
1540        const char *line_prefix = "";
1541        int extra_shown = 0;
1542
1543        if (data->nr == 0)
1544                return;
1545
1546        line_prefix = diff_line_prefix(options);
1547        count = options->stat_count ? options->stat_count : data->nr;
1548
1549        reset = diff_get_color_opt(options, DIFF_RESET);
1550        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1551        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1552
1553        /*
1554         * Find the longest filename and max number of changes
1555         */
1556        for (i = 0; (i < count) && (i < data->nr); i++) {
1557                struct diffstat_file *file = data->files[i];
1558                uintmax_t change = file->added + file->deleted;
1559
1560                if (!file->is_interesting && (change == 0)) {
1561                        count++; /* not shown == room for one more */
1562                        continue;
1563                }
1564                fill_print_name(file);
1565                len = strlen(file->print_name);
1566                if (max_len < len)
1567                        max_len = len;
1568
1569                if (file->is_unmerged) {
1570                        /* "Unmerged" is 8 characters */
1571                        bin_width = bin_width < 8 ? 8 : bin_width;
1572                        continue;
1573                }
1574                if (file->is_binary) {
1575                        /* "Bin XXX -> YYY bytes" */
1576                        int w = 14 + decimal_width(file->added)
1577                                + decimal_width(file->deleted);
1578                        bin_width = bin_width < w ? w : bin_width;
1579                        /* Display change counts aligned with "Bin" */
1580                        number_width = 3;
1581                        continue;
1582                }
1583
1584                if (max_change < change)
1585                        max_change = change;
1586        }
1587        count = i; /* where we can stop scanning in data->files[] */
1588
1589        /*
1590         * We have width = stat_width or term_columns() columns total.
1591         * We want a maximum of min(max_len, stat_name_width) for the name part.
1592         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1593         * We also need 1 for " " and 4 + decimal_width(max_change)
1594         * for " | NNNN " and one the empty column at the end, altogether
1595         * 6 + decimal_width(max_change).
1596         *
1597         * If there's not enough space, we will use the smaller of
1598         * stat_name_width (if set) and 5/8*width for the filename,
1599         * and the rest for constant elements + graph part, but no more
1600         * than stat_graph_width for the graph part.
1601         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1602         * for the standard terminal size).
1603         *
1604         * In other words: stat_width limits the maximum width, and
1605         * stat_name_width fixes the maximum width of the filename,
1606         * and is also used to divide available columns if there
1607         * aren't enough.
1608         *
1609         * Binary files are displayed with "Bin XXX -> YYY bytes"
1610         * instead of the change count and graph. This part is treated
1611         * similarly to the graph part, except that it is not
1612         * "scaled". If total width is too small to accommodate the
1613         * guaranteed minimum width of the filename part and the
1614         * separators and this message, this message will "overflow"
1615         * making the line longer than the maximum width.
1616         */
1617
1618        if (options->stat_width == -1)
1619                width = term_columns() - options->output_prefix_length;
1620        else
1621                width = options->stat_width ? options->stat_width : 80;
1622        number_width = decimal_width(max_change) > number_width ?
1623                decimal_width(max_change) : number_width;
1624
1625        if (options->stat_graph_width == -1)
1626                options->stat_graph_width = diff_stat_graph_width;
1627
1628        /*
1629         * Guarantee 3/8*16==6 for the graph part
1630         * and 5/8*16==10 for the filename part
1631         */
1632        if (width < 16 + 6 + number_width)
1633                width = 16 + 6 + number_width;
1634
1635        /*
1636         * First assign sizes that are wanted, ignoring available width.
1637         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1638         * starting from "XXX" should fit in graph_width.
1639         */
1640        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1641        if (options->stat_graph_width &&
1642            options->stat_graph_width < graph_width)
1643                graph_width = options->stat_graph_width;
1644
1645        name_width = (options->stat_name_width > 0 &&
1646                      options->stat_name_width < max_len) ?
1647                options->stat_name_width : max_len;
1648
1649        /*
1650         * Adjust adjustable widths not to exceed maximum width
1651         */
1652        if (name_width + number_width + 6 + graph_width > width) {
1653                if (graph_width > width * 3/8 - number_width - 6) {
1654                        graph_width = width * 3/8 - number_width - 6;
1655                        if (graph_width < 6)
1656                                graph_width = 6;
1657                }
1658
1659                if (options->stat_graph_width &&
1660                    graph_width > options->stat_graph_width)
1661                        graph_width = options->stat_graph_width;
1662                if (name_width > width - number_width - 6 - graph_width)
1663                        name_width = width - number_width - 6 - graph_width;
1664                else
1665                        graph_width = width - number_width - 6 - name_width;
1666        }
1667
1668        /*
1669         * From here name_width is the width of the name area,
1670         * and graph_width is the width of the graph area.
1671         * max_change is used to scale graph properly.
1672         */
1673        for (i = 0; i < count; i++) {
1674                const char *prefix = "";
1675                struct diffstat_file *file = data->files[i];
1676                char *name = file->print_name;
1677                uintmax_t added = file->added;
1678                uintmax_t deleted = file->deleted;
1679                int name_len;
1680
1681                if (!file->is_interesting && (added + deleted == 0))
1682                        continue;
1683
1684                /*
1685                 * "scale" the filename
1686                 */
1687                len = name_width;
1688                name_len = strlen(name);
1689                if (name_width < name_len) {
1690                        char *slash;
1691                        prefix = "...";
1692                        len -= 3;
1693                        name += name_len - len;
1694                        slash = strchr(name, '/');
1695                        if (slash)
1696                                name = slash;
1697                }
1698
1699                if (file->is_binary) {
1700                        fprintf(options->file, "%s", line_prefix);
1701                        show_name(options->file, prefix, name, len);
1702                        fprintf(options->file, " %*s", number_width, "Bin");
1703                        if (!added && !deleted) {
1704                                putc('\n', options->file);
1705                                continue;
1706                        }
1707                        fprintf(options->file, " %s%"PRIuMAX"%s",
1708                                del_c, deleted, reset);
1709                        fprintf(options->file, " -> ");
1710                        fprintf(options->file, "%s%"PRIuMAX"%s",
1711                                add_c, added, reset);
1712                        fprintf(options->file, " bytes");
1713                        fprintf(options->file, "\n");
1714                        continue;
1715                }
1716                else if (file->is_unmerged) {
1717                        fprintf(options->file, "%s", line_prefix);
1718                        show_name(options->file, prefix, name, len);
1719                        fprintf(options->file, " Unmerged\n");
1720                        continue;
1721                }
1722
1723                /*
1724                 * scale the add/delete
1725                 */
1726                add = added;
1727                del = deleted;
1728
1729                if (graph_width <= max_change) {
1730                        int total = scale_linear(add + del, graph_width, max_change);
1731                        if (total < 2 && add && del)
1732                                /* width >= 2 due to the sanity check */
1733                                total = 2;
1734                        if (add < del) {
1735                                add = scale_linear(add, graph_width, max_change);
1736                                del = total - add;
1737                        } else {
1738                                del = scale_linear(del, graph_width, max_change);
1739                                add = total - del;
1740                        }
1741                }
1742                fprintf(options->file, "%s", line_prefix);
1743                show_name(options->file, prefix, name, len);
1744                fprintf(options->file, " %*"PRIuMAX"%s",
1745                        number_width, added + deleted,
1746                        added + deleted ? " " : "");
1747                show_graph(options->file, '+', add, add_c, reset);
1748                show_graph(options->file, '-', del, del_c, reset);
1749                fprintf(options->file, "\n");
1750        }
1751
1752        for (i = 0; i < data->nr; i++) {
1753                struct diffstat_file *file = data->files[i];
1754                uintmax_t added = file->added;
1755                uintmax_t deleted = file->deleted;
1756
1757                if (file->is_unmerged ||
1758                    (!file->is_interesting && (added + deleted == 0))) {
1759                        total_files--;
1760                        continue;
1761                }
1762
1763                if (!file->is_binary) {
1764                        adds += added;
1765                        dels += deleted;
1766                }
1767                if (i < count)
1768                        continue;
1769                if (!extra_shown)
1770                        fprintf(options->file, "%s ...\n", line_prefix);
1771                extra_shown = 1;
1772        }
1773        fprintf(options->file, "%s", line_prefix);
1774        print_stat_summary(options->file, total_files, adds, dels);
1775}
1776
1777static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1778{
1779        int i, adds = 0, dels = 0, total_files = data->nr;
1780
1781        if (data->nr == 0)
1782                return;
1783
1784        for (i = 0; i < data->nr; i++) {
1785                int added = data->files[i]->added;
1786                int deleted= data->files[i]->deleted;
1787
1788                if (data->files[i]->is_unmerged ||
1789                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1790                        total_files--;
1791                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1792                        adds += added;
1793                        dels += deleted;
1794                }
1795        }
1796        fprintf(options->file, "%s", diff_line_prefix(options));
1797        print_stat_summary(options->file, total_files, adds, dels);
1798}
1799
1800static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1801{
1802        int i;
1803
1804        if (data->nr == 0)
1805                return;
1806
1807        for (i = 0; i < data->nr; i++) {
1808                struct diffstat_file *file = data->files[i];
1809
1810                fprintf(options->file, "%s", diff_line_prefix(options));
1811
1812                if (file->is_binary)
1813                        fprintf(options->file, "-\t-\t");
1814                else
1815                        fprintf(options->file,
1816                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1817                                file->added, file->deleted);
1818                if (options->line_termination) {
1819                        fill_print_name(file);
1820                        if (!file->is_renamed)
1821                                write_name_quoted(file->name, options->file,
1822                                                  options->line_termination);
1823                        else {
1824                                fputs(file->print_name, options->file);
1825                                putc(options->line_termination, options->file);
1826                        }
1827                } else {
1828                        if (file->is_renamed) {
1829                                putc('\0', options->file);
1830                                write_name_quoted(file->from_name, options->file, '\0');
1831                        }
1832                        write_name_quoted(file->name, options->file, '\0');
1833                }
1834        }
1835}
1836
1837struct dirstat_file {
1838        const char *name;
1839        unsigned long changed;
1840};
1841
1842struct dirstat_dir {
1843        struct dirstat_file *files;
1844        int alloc, nr, permille, cumulative;
1845};
1846
1847static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1848                unsigned long changed, const char *base, int baselen)
1849{
1850        unsigned long this_dir = 0;
1851        unsigned int sources = 0;
1852        const char *line_prefix = diff_line_prefix(opt);
1853
1854        while (dir->nr) {
1855                struct dirstat_file *f = dir->files;
1856                int namelen = strlen(f->name);
1857                unsigned long this;
1858                char *slash;
1859
1860                if (namelen < baselen)
1861                        break;
1862                if (memcmp(f->name, base, baselen))
1863                        break;
1864                slash = strchr(f->name + baselen, '/');
1865                if (slash) {
1866                        int newbaselen = slash + 1 - f->name;
1867                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1868                        sources++;
1869                } else {
1870                        this = f->changed;
1871                        dir->files++;
1872                        dir->nr--;
1873                        sources += 2;
1874                }
1875                this_dir += this;
1876        }
1877
1878        /*
1879         * We don't report dirstat's for
1880         *  - the top level
1881         *  - or cases where everything came from a single directory
1882         *    under this directory (sources == 1).
1883         */
1884        if (baselen && sources != 1) {
1885                if (this_dir) {
1886                        int permille = this_dir * 1000 / changed;
1887                        if (permille >= dir->permille) {
1888                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1889                                        permille / 10, permille % 10, baselen, base);
1890                                if (!dir->cumulative)
1891                                        return 0;
1892                        }
1893                }
1894        }
1895        return this_dir;
1896}
1897
1898static int dirstat_compare(const void *_a, const void *_b)
1899{
1900        const struct dirstat_file *a = _a;
1901        const struct dirstat_file *b = _b;
1902        return strcmp(a->name, b->name);
1903}
1904
1905static void show_dirstat(struct diff_options *options)
1906{
1907        int i;
1908        unsigned long changed;
1909        struct dirstat_dir dir;
1910        struct diff_queue_struct *q = &diff_queued_diff;
1911
1912        dir.files = NULL;
1913        dir.alloc = 0;
1914        dir.nr = 0;
1915        dir.permille = options->dirstat_permille;
1916        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1917
1918        changed = 0;
1919        for (i = 0; i < q->nr; i++) {
1920                struct diff_filepair *p = q->queue[i];
1921                const char *name;
1922                unsigned long copied, added, damage;
1923                int content_changed;
1924
1925                name = p->two->path ? p->two->path : p->one->path;
1926
1927                if (p->one->oid_valid && p->two->oid_valid)
1928                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
1929                else
1930                        content_changed = 1;
1931
1932                if (!content_changed) {
1933                        /*
1934                         * The SHA1 has not changed, so pre-/post-content is
1935                         * identical. We can therefore skip looking at the
1936                         * file contents altogether.
1937                         */
1938                        damage = 0;
1939                        goto found_damage;
1940                }
1941
1942                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1943                        /*
1944                         * In --dirstat-by-file mode, we don't really need to
1945                         * look at the actual file contents at all.
1946                         * The fact that the SHA1 changed is enough for us to
1947                         * add this file to the list of results
1948                         * (with each file contributing equal damage).
1949                         */
1950                        damage = 1;
1951                        goto found_damage;
1952                }
1953
1954                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1955                        diff_populate_filespec(p->one, 0);
1956                        diff_populate_filespec(p->two, 0);
1957                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1958                                               &copied, &added);
1959                        diff_free_filespec_data(p->one);
1960                        diff_free_filespec_data(p->two);
1961                } else if (DIFF_FILE_VALID(p->one)) {
1962                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1963                        copied = added = 0;
1964                        diff_free_filespec_data(p->one);
1965                } else if (DIFF_FILE_VALID(p->two)) {
1966                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1967                        copied = 0;
1968                        added = p->two->size;
1969                        diff_free_filespec_data(p->two);
1970                } else
1971                        continue;
1972
1973                /*
1974                 * Original minus copied is the removed material,
1975                 * added is the new material.  They are both damages
1976                 * made to the preimage.
1977                 * If the resulting damage is zero, we know that
1978                 * diffcore_count_changes() considers the two entries to
1979                 * be identical, but since content_changed is true, we
1980                 * know that there must have been _some_ kind of change,
1981                 * so we force all entries to have damage > 0.
1982                 */
1983                damage = (p->one->size - copied) + added;
1984                if (!damage)
1985                        damage = 1;
1986
1987found_damage:
1988                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1989                dir.files[dir.nr].name = name;
1990                dir.files[dir.nr].changed = damage;
1991                changed += damage;
1992                dir.nr++;
1993        }
1994
1995        /* This can happen even with many files, if everything was renames */
1996        if (!changed)
1997                return;
1998
1999        /* Show all directories with more than x% of the changes */
2000        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2001        gather_dirstat(options, &dir, changed, "", 0);
2002}
2003
2004static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2005{
2006        int i;
2007        unsigned long changed;
2008        struct dirstat_dir dir;
2009
2010        if (data->nr == 0)
2011                return;
2012
2013        dir.files = NULL;
2014        dir.alloc = 0;
2015        dir.nr = 0;
2016        dir.permille = options->dirstat_permille;
2017        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2018
2019        changed = 0;
2020        for (i = 0; i < data->nr; i++) {
2021                struct diffstat_file *file = data->files[i];
2022                unsigned long damage = file->added + file->deleted;
2023                if (file->is_binary)
2024                        /*
2025                         * binary files counts bytes, not lines. Must find some
2026                         * way to normalize binary bytes vs. textual lines.
2027                         * The following heuristic assumes that there are 64
2028                         * bytes per "line".
2029                         * This is stupid and ugly, but very cheap...
2030                         */
2031                        damage = (damage + 63) / 64;
2032                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2033                dir.files[dir.nr].name = file->name;
2034                dir.files[dir.nr].changed = damage;
2035                changed += damage;
2036                dir.nr++;
2037        }
2038
2039        /* This can happen even with many files, if everything was renames */
2040        if (!changed)
2041                return;
2042
2043        /* Show all directories with more than x% of the changes */
2044        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2045        gather_dirstat(options, &dir, changed, "", 0);
2046}
2047
2048static void free_diffstat_info(struct diffstat_t *diffstat)
2049{
2050        int i;
2051        for (i = 0; i < diffstat->nr; i++) {
2052                struct diffstat_file *f = diffstat->files[i];
2053                if (f->name != f->print_name)
2054                        free(f->print_name);
2055                free(f->name);
2056                free(f->from_name);
2057                free(f);
2058        }
2059        free(diffstat->files);
2060}
2061
2062struct checkdiff_t {
2063        const char *filename;
2064        int lineno;
2065        int conflict_marker_size;
2066        struct diff_options *o;
2067        unsigned ws_rule;
2068        unsigned status;
2069};
2070
2071static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2072{
2073        char firstchar;
2074        int cnt;
2075
2076        if (len < marker_size + 1)
2077                return 0;
2078        firstchar = line[0];
2079        switch (firstchar) {
2080        case '=': case '>': case '<': case '|':
2081                break;
2082        default:
2083                return 0;
2084        }
2085        for (cnt = 1; cnt < marker_size; cnt++)
2086                if (line[cnt] != firstchar)
2087                        return 0;
2088        /* line[1] thru line[marker_size-1] are same as firstchar */
2089        if (len < marker_size + 1 || !isspace(line[marker_size]))
2090                return 0;
2091        return 1;
2092}
2093
2094static void checkdiff_consume(void *priv, char *line, unsigned long len)
2095{
2096        struct checkdiff_t *data = priv;
2097        int marker_size = data->conflict_marker_size;
2098        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2099        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2100        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2101        char *err;
2102        const char *line_prefix;
2103
2104        assert(data->o);
2105        line_prefix = diff_line_prefix(data->o);
2106
2107        if (line[0] == '+') {
2108                unsigned bad;
2109                data->lineno++;
2110                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2111                        data->status |= 1;
2112                        fprintf(data->o->file,
2113                                "%s%s:%d: leftover conflict marker\n",
2114                                line_prefix, data->filename, data->lineno);
2115                }
2116                bad = ws_check(line + 1, len - 1, data->ws_rule);
2117                if (!bad)
2118                        return;
2119                data->status |= bad;
2120                err = whitespace_error_string(bad);
2121                fprintf(data->o->file, "%s%s:%d: %s.\n",
2122                        line_prefix, data->filename, data->lineno, err);
2123                free(err);
2124                emit_line(data->o, set, reset, line, 1);
2125                ws_check_emit(line + 1, len - 1, data->ws_rule,
2126                              data->o->file, set, reset, ws);
2127        } else if (line[0] == ' ') {
2128                data->lineno++;
2129        } else if (line[0] == '@') {
2130                char *plus = strchr(line, '+');
2131                if (plus)
2132                        data->lineno = strtol(plus, NULL, 10) - 1;
2133                else
2134                        die("invalid diff");
2135        }
2136}
2137
2138static unsigned char *deflate_it(char *data,
2139                                 unsigned long size,
2140                                 unsigned long *result_size)
2141{
2142        int bound;
2143        unsigned char *deflated;
2144        git_zstream stream;
2145
2146        git_deflate_init(&stream, zlib_compression_level);
2147        bound = git_deflate_bound(&stream, size);
2148        deflated = xmalloc(bound);
2149        stream.next_out = deflated;
2150        stream.avail_out = bound;
2151
2152        stream.next_in = (unsigned char *)data;
2153        stream.avail_in = size;
2154        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2155                ; /* nothing */
2156        git_deflate_end(&stream);
2157        *result_size = stream.total_out;
2158        return deflated;
2159}
2160
2161static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2162                                  const char *prefix)
2163{
2164        void *cp;
2165        void *delta;
2166        void *deflated;
2167        void *data;
2168        unsigned long orig_size;
2169        unsigned long delta_size;
2170        unsigned long deflate_size;
2171        unsigned long data_size;
2172
2173        /* We could do deflated delta, or we could do just deflated two,
2174         * whichever is smaller.
2175         */
2176        delta = NULL;
2177        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2178        if (one->size && two->size) {
2179                delta = diff_delta(one->ptr, one->size,
2180                                   two->ptr, two->size,
2181                                   &delta_size, deflate_size);
2182                if (delta) {
2183                        void *to_free = delta;
2184                        orig_size = delta_size;
2185                        delta = deflate_it(delta, delta_size, &delta_size);
2186                        free(to_free);
2187                }
2188        }
2189
2190        if (delta && delta_size < deflate_size) {
2191                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2192                free(deflated);
2193                data = delta;
2194                data_size = delta_size;
2195        }
2196        else {
2197                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2198                free(delta);
2199                data = deflated;
2200                data_size = deflate_size;
2201        }
2202
2203        /* emit data encoded in base85 */
2204        cp = data;
2205        while (data_size) {
2206                int bytes = (52 < data_size) ? 52 : data_size;
2207                char line[70];
2208                data_size -= bytes;
2209                if (bytes <= 26)
2210                        line[0] = bytes + 'A' - 1;
2211                else
2212                        line[0] = bytes - 26 + 'a' - 1;
2213                encode_85(line + 1, cp, bytes);
2214                cp = (char *) cp + bytes;
2215                fprintf(file, "%s", prefix);
2216                fputs(line, file);
2217                fputc('\n', file);
2218        }
2219        fprintf(file, "%s\n", prefix);
2220        free(data);
2221}
2222
2223static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2224                             const char *prefix)
2225{
2226        fprintf(file, "%sGIT binary patch\n", prefix);
2227        emit_binary_diff_body(file, one, two, prefix);
2228        emit_binary_diff_body(file, two, one, prefix);
2229}
2230
2231int diff_filespec_is_binary(struct diff_filespec *one)
2232{
2233        if (one->is_binary == -1) {
2234                diff_filespec_load_driver(one);
2235                if (one->driver->binary != -1)
2236                        one->is_binary = one->driver->binary;
2237                else {
2238                        if (!one->data && DIFF_FILE_VALID(one))
2239                                diff_populate_filespec(one, CHECK_BINARY);
2240                        if (one->is_binary == -1 && one->data)
2241                                one->is_binary = buffer_is_binary(one->data,
2242                                                one->size);
2243                        if (one->is_binary == -1)
2244                                one->is_binary = 0;
2245                }
2246        }
2247        return one->is_binary;
2248}
2249
2250static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2251{
2252        diff_filespec_load_driver(one);
2253        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2254}
2255
2256void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2257{
2258        if (!options->a_prefix)
2259                options->a_prefix = a;
2260        if (!options->b_prefix)
2261                options->b_prefix = b;
2262}
2263
2264struct userdiff_driver *get_textconv(struct diff_filespec *one)
2265{
2266        if (!DIFF_FILE_VALID(one))
2267                return NULL;
2268
2269        diff_filespec_load_driver(one);
2270        return userdiff_get_textconv(one->driver);
2271}
2272
2273static void builtin_diff(const char *name_a,
2274                         const char *name_b,
2275                         struct diff_filespec *one,
2276                         struct diff_filespec *two,
2277                         const char *xfrm_msg,
2278                         int must_show_header,
2279                         struct diff_options *o,
2280                         int complete_rewrite)
2281{
2282        mmfile_t mf1, mf2;
2283        const char *lbl[2];
2284        char *a_one, *b_two;
2285        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2286        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2287        const char *a_prefix, *b_prefix;
2288        struct userdiff_driver *textconv_one = NULL;
2289        struct userdiff_driver *textconv_two = NULL;
2290        struct strbuf header = STRBUF_INIT;
2291        const char *line_prefix = diff_line_prefix(o);
2292
2293        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2294                        (!one->mode || S_ISGITLINK(one->mode)) &&
2295                        (!two->mode || S_ISGITLINK(two->mode))) {
2296                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2297                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2298                show_submodule_summary(o->file, one->path ? one->path : two->path,
2299                                line_prefix,
2300                                one->oid.hash, two->oid.hash,
2301                                two->dirty_submodule,
2302                                meta, del, add, reset);
2303                return;
2304        }
2305
2306        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2307                textconv_one = get_textconv(one);
2308                textconv_two = get_textconv(two);
2309        }
2310
2311        diff_set_mnemonic_prefix(o, "a/", "b/");
2312        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2313                a_prefix = o->b_prefix;
2314                b_prefix = o->a_prefix;
2315        } else {
2316                a_prefix = o->a_prefix;
2317                b_prefix = o->b_prefix;
2318        }
2319
2320        /* Never use a non-valid filename anywhere if at all possible */
2321        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2322        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2323
2324        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2325        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2326        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2327        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2328        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2329        if (lbl[0][0] == '/') {
2330                /* /dev/null */
2331                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2332                if (xfrm_msg)
2333                        strbuf_addstr(&header, xfrm_msg);
2334                must_show_header = 1;
2335        }
2336        else if (lbl[1][0] == '/') {
2337                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2338                if (xfrm_msg)
2339                        strbuf_addstr(&header, xfrm_msg);
2340                must_show_header = 1;
2341        }
2342        else {
2343                if (one->mode != two->mode) {
2344                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2345                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2346                        must_show_header = 1;
2347                }
2348                if (xfrm_msg)
2349                        strbuf_addstr(&header, xfrm_msg);
2350
2351                /*
2352                 * we do not run diff between different kind
2353                 * of objects.
2354                 */
2355                if ((one->mode ^ two->mode) & S_IFMT)
2356                        goto free_ab_and_return;
2357                if (complete_rewrite &&
2358                    (textconv_one || !diff_filespec_is_binary(one)) &&
2359                    (textconv_two || !diff_filespec_is_binary(two))) {
2360                        fprintf(o->file, "%s", header.buf);
2361                        strbuf_reset(&header);
2362                        emit_rewrite_diff(name_a, name_b, one, two,
2363                                                textconv_one, textconv_two, o);
2364                        o->found_changes = 1;
2365                        goto free_ab_and_return;
2366                }
2367        }
2368
2369        if (o->irreversible_delete && lbl[1][0] == '/') {
2370                fprintf(o->file, "%s", header.buf);
2371                strbuf_reset(&header);
2372                goto free_ab_and_return;
2373        } else if (!DIFF_OPT_TST(o, TEXT) &&
2374            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2375              (!textconv_two && diff_filespec_is_binary(two)) )) {
2376                if (!one->data && !two->data &&
2377                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2378                    !DIFF_OPT_TST(o, BINARY)) {
2379                        if (!oidcmp(&one->oid, &two->oid)) {
2380                                if (must_show_header)
2381                                        fprintf(o->file, "%s", header.buf);
2382                                goto free_ab_and_return;
2383                        }
2384                        fprintf(o->file, "%s", header.buf);
2385                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2386                                line_prefix, lbl[0], lbl[1]);
2387                        goto free_ab_and_return;
2388                }
2389                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2390                        die("unable to read files to diff");
2391                /* Quite common confusing case */
2392                if (mf1.size == mf2.size &&
2393                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2394                        if (must_show_header)
2395                                fprintf(o->file, "%s", header.buf);
2396                        goto free_ab_and_return;
2397                }
2398                fprintf(o->file, "%s", header.buf);
2399                strbuf_reset(&header);
2400                if (DIFF_OPT_TST(o, BINARY))
2401                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2402                else
2403                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2404                                line_prefix, lbl[0], lbl[1]);
2405                o->found_changes = 1;
2406        } else {
2407                /* Crazy xdl interfaces.. */
2408                const char *diffopts = getenv("GIT_DIFF_OPTS");
2409                const char *v;
2410                xpparam_t xpp;
2411                xdemitconf_t xecfg;
2412                struct emit_callback ecbdata;
2413                const struct userdiff_funcname *pe;
2414
2415                if (must_show_header) {
2416                        fprintf(o->file, "%s", header.buf);
2417                        strbuf_reset(&header);
2418                }
2419
2420                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2421                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2422
2423                pe = diff_funcname_pattern(one);
2424                if (!pe)
2425                        pe = diff_funcname_pattern(two);
2426
2427                memset(&xpp, 0, sizeof(xpp));
2428                memset(&xecfg, 0, sizeof(xecfg));
2429                memset(&ecbdata, 0, sizeof(ecbdata));
2430                ecbdata.label_path = lbl;
2431                ecbdata.color_diff = want_color(o->use_color);
2432                ecbdata.ws_rule = whitespace_rule(name_b);
2433                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2434                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2435                ecbdata.opt = o;
2436                ecbdata.header = header.len ? &header : NULL;
2437                xpp.flags = o->xdl_opts;
2438                xecfg.ctxlen = o->context;
2439                xecfg.interhunkctxlen = o->interhunkcontext;
2440                xecfg.flags = XDL_EMIT_FUNCNAMES;
2441                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2442                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2443                if (pe)
2444                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2445                if (!diffopts)
2446                        ;
2447                else if (skip_prefix(diffopts, "--unified=", &v))
2448                        xecfg.ctxlen = strtoul(v, NULL, 10);
2449                else if (skip_prefix(diffopts, "-u", &v))
2450                        xecfg.ctxlen = strtoul(v, NULL, 10);
2451                if (o->word_diff)
2452                        init_diff_words_data(&ecbdata, o, one, two);
2453                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2454                                  &xpp, &xecfg))
2455                        die("unable to generate diff for %s", one->path);
2456                if (o->word_diff)
2457                        free_diff_words_data(&ecbdata);
2458                if (textconv_one)
2459                        free(mf1.ptr);
2460                if (textconv_two)
2461                        free(mf2.ptr);
2462                xdiff_clear_find_func(&xecfg);
2463        }
2464
2465 free_ab_and_return:
2466        strbuf_release(&header);
2467        diff_free_filespec_data(one);
2468        diff_free_filespec_data(two);
2469        free(a_one);
2470        free(b_two);
2471        return;
2472}
2473
2474static void builtin_diffstat(const char *name_a, const char *name_b,
2475                             struct diff_filespec *one,
2476                             struct diff_filespec *two,
2477                             struct diffstat_t *diffstat,
2478                             struct diff_options *o,
2479                             struct diff_filepair *p)
2480{
2481        mmfile_t mf1, mf2;
2482        struct diffstat_file *data;
2483        int same_contents;
2484        int complete_rewrite = 0;
2485
2486        if (!DIFF_PAIR_UNMERGED(p)) {
2487                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2488                        complete_rewrite = 1;
2489        }
2490
2491        data = diffstat_add(diffstat, name_a, name_b);
2492        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2493
2494        if (!one || !two) {
2495                data->is_unmerged = 1;
2496                return;
2497        }
2498
2499        same_contents = !oidcmp(&one->oid, &two->oid);
2500
2501        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2502                data->is_binary = 1;
2503                if (same_contents) {
2504                        data->added = 0;
2505                        data->deleted = 0;
2506                } else {
2507                        data->added = diff_filespec_size(two);
2508                        data->deleted = diff_filespec_size(one);
2509                }
2510        }
2511
2512        else if (complete_rewrite) {
2513                diff_populate_filespec(one, 0);
2514                diff_populate_filespec(two, 0);
2515                data->deleted = count_lines(one->data, one->size);
2516                data->added = count_lines(two->data, two->size);
2517        }
2518
2519        else if (!same_contents) {
2520                /* Crazy xdl interfaces.. */
2521                xpparam_t xpp;
2522                xdemitconf_t xecfg;
2523
2524                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2525                        die("unable to read files to diff");
2526
2527                memset(&xpp, 0, sizeof(xpp));
2528                memset(&xecfg, 0, sizeof(xecfg));
2529                xpp.flags = o->xdl_opts;
2530                xecfg.ctxlen = o->context;
2531                xecfg.interhunkctxlen = o->interhunkcontext;
2532                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2533                                  &xpp, &xecfg))
2534                        die("unable to generate diffstat for %s", one->path);
2535        }
2536
2537        diff_free_filespec_data(one);
2538        diff_free_filespec_data(two);
2539}
2540
2541static void builtin_checkdiff(const char *name_a, const char *name_b,
2542                              const char *attr_path,
2543                              struct diff_filespec *one,
2544                              struct diff_filespec *two,
2545                              struct diff_options *o)
2546{
2547        mmfile_t mf1, mf2;
2548        struct checkdiff_t data;
2549
2550        if (!two)
2551                return;
2552
2553        memset(&data, 0, sizeof(data));
2554        data.filename = name_b ? name_b : name_a;
2555        data.lineno = 0;
2556        data.o = o;
2557        data.ws_rule = whitespace_rule(attr_path);
2558        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2559
2560        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2561                die("unable to read files to diff");
2562
2563        /*
2564         * All the other codepaths check both sides, but not checking
2565         * the "old" side here is deliberate.  We are checking the newly
2566         * introduced changes, and as long as the "new" side is text, we
2567         * can and should check what it introduces.
2568         */
2569        if (diff_filespec_is_binary(two))
2570                goto free_and_return;
2571        else {
2572                /* Crazy xdl interfaces.. */
2573                xpparam_t xpp;
2574                xdemitconf_t xecfg;
2575
2576                memset(&xpp, 0, sizeof(xpp));
2577                memset(&xecfg, 0, sizeof(xecfg));
2578                xecfg.ctxlen = 1; /* at least one context line */
2579                xpp.flags = 0;
2580                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2581                                  &xpp, &xecfg))
2582                        die("unable to generate checkdiff for %s", one->path);
2583
2584                if (data.ws_rule & WS_BLANK_AT_EOF) {
2585                        struct emit_callback ecbdata;
2586                        int blank_at_eof;
2587
2588                        ecbdata.ws_rule = data.ws_rule;
2589                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2590                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2591
2592                        if (blank_at_eof) {
2593                                static char *err;
2594                                if (!err)
2595                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2596                                fprintf(o->file, "%s:%d: %s.\n",
2597                                        data.filename, blank_at_eof, err);
2598                                data.status = 1; /* report errors */
2599                        }
2600                }
2601        }
2602 free_and_return:
2603        diff_free_filespec_data(one);
2604        diff_free_filespec_data(two);
2605        if (data.status)
2606                DIFF_OPT_SET(o, CHECK_FAILED);
2607}
2608
2609struct diff_filespec *alloc_filespec(const char *path)
2610{
2611        struct diff_filespec *spec;
2612
2613        FLEXPTR_ALLOC_STR(spec, path, path);
2614        spec->count = 1;
2615        spec->is_binary = -1;
2616        return spec;
2617}
2618
2619void free_filespec(struct diff_filespec *spec)
2620{
2621        if (!--spec->count) {
2622                diff_free_filespec_data(spec);
2623                free(spec);
2624        }
2625}
2626
2627void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2628                   int sha1_valid, unsigned short mode)
2629{
2630        if (mode) {
2631                spec->mode = canon_mode(mode);
2632                hashcpy(spec->oid.hash, sha1);
2633                spec->oid_valid = sha1_valid;
2634        }
2635}
2636
2637/*
2638 * Given a name and sha1 pair, if the index tells us the file in
2639 * the work tree has that object contents, return true, so that
2640 * prepare_temp_file() does not have to inflate and extract.
2641 */
2642static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2643{
2644        const struct cache_entry *ce;
2645        struct stat st;
2646        int pos, len;
2647
2648        /*
2649         * We do not read the cache ourselves here, because the
2650         * benchmark with my previous version that always reads cache
2651         * shows that it makes things worse for diff-tree comparing
2652         * two linux-2.6 kernel trees in an already checked out work
2653         * tree.  This is because most diff-tree comparisons deal with
2654         * only a small number of files, while reading the cache is
2655         * expensive for a large project, and its cost outweighs the
2656         * savings we get by not inflating the object to a temporary
2657         * file.  Practically, this code only helps when we are used
2658         * by diff-cache --cached, which does read the cache before
2659         * calling us.
2660         */
2661        if (!active_cache)
2662                return 0;
2663
2664        /* We want to avoid the working directory if our caller
2665         * doesn't need the data in a normal file, this system
2666         * is rather slow with its stat/open/mmap/close syscalls,
2667         * and the object is contained in a pack file.  The pack
2668         * is probably already open and will be faster to obtain
2669         * the data through than the working directory.  Loose
2670         * objects however would tend to be slower as they need
2671         * to be individually opened and inflated.
2672         */
2673        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2674                return 0;
2675
2676        /*
2677         * Similarly, if we'd have to convert the file contents anyway, that
2678         * makes the optimization not worthwhile.
2679         */
2680        if (!want_file && would_convert_to_git(name))
2681                return 0;
2682
2683        len = strlen(name);
2684        pos = cache_name_pos(name, len);
2685        if (pos < 0)
2686                return 0;
2687        ce = active_cache[pos];
2688
2689        /*
2690         * This is not the sha1 we are looking for, or
2691         * unreusable because it is not a regular file.
2692         */
2693        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2694                return 0;
2695
2696        /*
2697         * If ce is marked as "assume unchanged", there is no
2698         * guarantee that work tree matches what we are looking for.
2699         */
2700        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2701                return 0;
2702
2703        /*
2704         * If ce matches the file in the work tree, we can reuse it.
2705         */
2706        if (ce_uptodate(ce) ||
2707            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2708                return 1;
2709
2710        return 0;
2711}
2712
2713static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2714{
2715        struct strbuf buf = STRBUF_INIT;
2716        char *dirty = "";
2717
2718        /* Are we looking at the work tree? */
2719        if (s->dirty_submodule)
2720                dirty = "-dirty";
2721
2722        strbuf_addf(&buf, "Subproject commit %s%s\n",
2723                    oid_to_hex(&s->oid), dirty);
2724        s->size = buf.len;
2725        if (size_only) {
2726                s->data = NULL;
2727                strbuf_release(&buf);
2728        } else {
2729                s->data = strbuf_detach(&buf, NULL);
2730                s->should_free = 1;
2731        }
2732        return 0;
2733}
2734
2735/*
2736 * While doing rename detection and pickaxe operation, we may need to
2737 * grab the data for the blob (or file) for our own in-core comparison.
2738 * diff_filespec has data and size fields for this purpose.
2739 */
2740int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2741{
2742        int size_only = flags & CHECK_SIZE_ONLY;
2743        int err = 0;
2744        /*
2745         * demote FAIL to WARN to allow inspecting the situation
2746         * instead of refusing.
2747         */
2748        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2749                                    ? SAFE_CRLF_WARN
2750                                    : safe_crlf);
2751
2752        if (!DIFF_FILE_VALID(s))
2753                die("internal error: asking to populate invalid file.");
2754        if (S_ISDIR(s->mode))
2755                return -1;
2756
2757        if (s->data)
2758                return 0;
2759
2760        if (size_only && 0 < s->size)
2761                return 0;
2762
2763        if (S_ISGITLINK(s->mode))
2764                return diff_populate_gitlink(s, size_only);
2765
2766        if (!s->oid_valid ||
2767            reuse_worktree_file(s->path, s->oid.hash, 0)) {
2768                struct strbuf buf = STRBUF_INIT;
2769                struct stat st;
2770                int fd;
2771
2772                if (lstat(s->path, &st) < 0) {
2773                        if (errno == ENOENT) {
2774                        err_empty:
2775                                err = -1;
2776                        empty:
2777                                s->data = (char *)"";
2778                                s->size = 0;
2779                                return err;
2780                        }
2781                }
2782                s->size = xsize_t(st.st_size);
2783                if (!s->size)
2784                        goto empty;
2785                if (S_ISLNK(st.st_mode)) {
2786                        struct strbuf sb = STRBUF_INIT;
2787
2788                        if (strbuf_readlink(&sb, s->path, s->size))
2789                                goto err_empty;
2790                        s->size = sb.len;
2791                        s->data = strbuf_detach(&sb, NULL);
2792                        s->should_free = 1;
2793                        return 0;
2794                }
2795                if (size_only)
2796                        return 0;
2797                if ((flags & CHECK_BINARY) &&
2798                    s->size > big_file_threshold && s->is_binary == -1) {
2799                        s->is_binary = 1;
2800                        return 0;
2801                }
2802                fd = open(s->path, O_RDONLY);
2803                if (fd < 0)
2804                        goto err_empty;
2805                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2806                close(fd);
2807                s->should_munmap = 1;
2808
2809                /*
2810                 * Convert from working tree format to canonical git format
2811                 */
2812                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2813                        size_t size = 0;
2814                        munmap(s->data, s->size);
2815                        s->should_munmap = 0;
2816                        s->data = strbuf_detach(&buf, &size);
2817                        s->size = size;
2818                        s->should_free = 1;
2819                }
2820        }
2821        else {
2822                enum object_type type;
2823                if (size_only || (flags & CHECK_BINARY)) {
2824                        type = sha1_object_info(s->oid.hash, &s->size);
2825                        if (type < 0)
2826                                die("unable to read %s",
2827                                    oid_to_hex(&s->oid));
2828                        if (size_only)
2829                                return 0;
2830                        if (s->size > big_file_threshold && s->is_binary == -1) {
2831                                s->is_binary = 1;
2832                                return 0;
2833                        }
2834                }
2835                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2836                if (!s->data)
2837                        die("unable to read %s", oid_to_hex(&s->oid));
2838                s->should_free = 1;
2839        }
2840        return 0;
2841}
2842
2843void diff_free_filespec_blob(struct diff_filespec *s)
2844{
2845        if (s->should_free)
2846                free(s->data);
2847        else if (s->should_munmap)
2848                munmap(s->data, s->size);
2849
2850        if (s->should_free || s->should_munmap) {
2851                s->should_free = s->should_munmap = 0;
2852                s->data = NULL;
2853        }
2854}
2855
2856void diff_free_filespec_data(struct diff_filespec *s)
2857{
2858        diff_free_filespec_blob(s);
2859        free(s->cnt_data);
2860        s->cnt_data = NULL;
2861}
2862
2863static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2864                           void *blob,
2865                           unsigned long size,
2866                           const struct object_id *oid,
2867                           int mode)
2868{
2869        int fd;
2870        struct strbuf buf = STRBUF_INIT;
2871        struct strbuf template = STRBUF_INIT;
2872        char *path_dup = xstrdup(path);
2873        const char *base = basename(path_dup);
2874
2875        /* Generate "XXXXXX_basename.ext" */
2876        strbuf_addstr(&template, "XXXXXX_");
2877        strbuf_addstr(&template, base);
2878
2879        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2880        if (fd < 0)
2881                die_errno("unable to create temp-file");
2882        if (convert_to_working_tree(path,
2883                        (const char *)blob, (size_t)size, &buf)) {
2884                blob = buf.buf;
2885                size = buf.len;
2886        }
2887        if (write_in_full(fd, blob, size) != size)
2888                die_errno("unable to write temp-file");
2889        close_tempfile(&temp->tempfile);
2890        temp->name = get_tempfile_path(&temp->tempfile);
2891        oid_to_hex_r(temp->hex, oid);
2892        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2893        strbuf_release(&buf);
2894        strbuf_release(&template);
2895        free(path_dup);
2896}
2897
2898static struct diff_tempfile *prepare_temp_file(const char *name,
2899                struct diff_filespec *one)
2900{
2901        struct diff_tempfile *temp = claim_diff_tempfile();
2902
2903        if (!DIFF_FILE_VALID(one)) {
2904        not_a_valid_file:
2905                /* A '-' entry produces this for file-2, and
2906                 * a '+' entry produces this for file-1.
2907                 */
2908                temp->name = "/dev/null";
2909                xsnprintf(temp->hex, sizeof(temp->hex), ".");
2910                xsnprintf(temp->mode, sizeof(temp->mode), ".");
2911                return temp;
2912        }
2913
2914        if (!S_ISGITLINK(one->mode) &&
2915            (!one->oid_valid ||
2916             reuse_worktree_file(name, one->oid.hash, 1))) {
2917                struct stat st;
2918                if (lstat(name, &st) < 0) {
2919                        if (errno == ENOENT)
2920                                goto not_a_valid_file;
2921                        die_errno("stat(%s)", name);
2922                }
2923                if (S_ISLNK(st.st_mode)) {
2924                        struct strbuf sb = STRBUF_INIT;
2925                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2926                                die_errno("readlink(%s)", name);
2927                        prep_temp_blob(name, temp, sb.buf, sb.len,
2928                                       (one->oid_valid ?
2929                                        &one->oid : &null_oid),
2930                                       (one->oid_valid ?
2931                                        one->mode : S_IFLNK));
2932                        strbuf_release(&sb);
2933                }
2934                else {
2935                        /* we can borrow from the file in the work tree */
2936                        temp->name = name;
2937                        if (!one->oid_valid)
2938                                sha1_to_hex_r(temp->hex, null_sha1);
2939                        else
2940                                sha1_to_hex_r(temp->hex, one->oid.hash);
2941                        /* Even though we may sometimes borrow the
2942                         * contents from the work tree, we always want
2943                         * one->mode.  mode is trustworthy even when
2944                         * !(one->sha1_valid), as long as
2945                         * DIFF_FILE_VALID(one).
2946                         */
2947                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2948                }
2949                return temp;
2950        }
2951        else {
2952                if (diff_populate_filespec(one, 0))
2953                        die("cannot read data blob for %s", one->path);
2954                prep_temp_blob(name, temp, one->data, one->size,
2955                               &one->oid, one->mode);
2956        }
2957        return temp;
2958}
2959
2960static void add_external_diff_name(struct argv_array *argv,
2961                                   const char *name,
2962                                   struct diff_filespec *df)
2963{
2964        struct diff_tempfile *temp = prepare_temp_file(name, df);
2965        argv_array_push(argv, temp->name);
2966        argv_array_push(argv, temp->hex);
2967        argv_array_push(argv, temp->mode);
2968}
2969
2970/* An external diff command takes:
2971 *
2972 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2973 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2974 *
2975 */
2976static void run_external_diff(const char *pgm,
2977                              const char *name,
2978                              const char *other,
2979                              struct diff_filespec *one,
2980                              struct diff_filespec *two,
2981                              const char *xfrm_msg,
2982                              int complete_rewrite,
2983                              struct diff_options *o)
2984{
2985        struct argv_array argv = ARGV_ARRAY_INIT;
2986        struct argv_array env = ARGV_ARRAY_INIT;
2987        struct diff_queue_struct *q = &diff_queued_diff;
2988
2989        argv_array_push(&argv, pgm);
2990        argv_array_push(&argv, name);
2991
2992        if (one && two) {
2993                add_external_diff_name(&argv, name, one);
2994                if (!other)
2995                        add_external_diff_name(&argv, name, two);
2996                else {
2997                        add_external_diff_name(&argv, other, two);
2998                        argv_array_push(&argv, other);
2999                        argv_array_push(&argv, xfrm_msg);
3000                }
3001        }
3002
3003        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3004        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3005
3006        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3007                die(_("external diff died, stopping at %s"), name);
3008
3009        remove_tempfile();
3010        argv_array_clear(&argv);
3011        argv_array_clear(&env);
3012}
3013
3014static int similarity_index(struct diff_filepair *p)
3015{
3016        return p->score * 100 / MAX_SCORE;
3017}
3018
3019static void fill_metainfo(struct strbuf *msg,
3020                          const char *name,
3021                          const char *other,
3022                          struct diff_filespec *one,
3023                          struct diff_filespec *two,
3024                          struct diff_options *o,
3025                          struct diff_filepair *p,
3026                          int *must_show_header,
3027                          int use_color)
3028{
3029        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3030        const char *reset = diff_get_color(use_color, DIFF_RESET);
3031        const char *line_prefix = diff_line_prefix(o);
3032
3033        *must_show_header = 1;
3034        strbuf_init(msg, PATH_MAX * 2 + 300);
3035        switch (p->status) {
3036        case DIFF_STATUS_COPIED:
3037                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3038                            line_prefix, set, similarity_index(p));
3039                strbuf_addf(msg, "%s\n%s%scopy from ",
3040                            reset,  line_prefix, set);
3041                quote_c_style(name, msg, NULL, 0);
3042                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3043                quote_c_style(other, msg, NULL, 0);
3044                strbuf_addf(msg, "%s\n", reset);
3045                break;
3046        case DIFF_STATUS_RENAMED:
3047                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3048                            line_prefix, set, similarity_index(p));
3049                strbuf_addf(msg, "%s\n%s%srename from ",
3050                            reset, line_prefix, set);
3051                quote_c_style(name, msg, NULL, 0);
3052                strbuf_addf(msg, "%s\n%s%srename to ",
3053                            reset, line_prefix, set);
3054                quote_c_style(other, msg, NULL, 0);
3055                strbuf_addf(msg, "%s\n", reset);
3056                break;
3057        case DIFF_STATUS_MODIFIED:
3058                if (p->score) {
3059                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3060                                    line_prefix,
3061                                    set, similarity_index(p), reset);
3062                        break;
3063                }
3064                /* fallthru */
3065        default:
3066                *must_show_header = 0;
3067        }
3068        if (one && two && oidcmp(&one->oid, &two->oid)) {
3069                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3070
3071                if (DIFF_OPT_TST(o, BINARY)) {
3072                        mmfile_t mf;
3073                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3074                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3075                                abbrev = 40;
3076                }
3077                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3078                            find_unique_abbrev(one->oid.hash, abbrev));
3079                strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
3080                if (one->mode == two->mode)
3081                        strbuf_addf(msg, " %06o", one->mode);
3082                strbuf_addf(msg, "%s\n", reset);
3083        }
3084}
3085
3086static void run_diff_cmd(const char *pgm,
3087                         const char *name,
3088                         const char *other,
3089                         const char *attr_path,
3090                         struct diff_filespec *one,
3091                         struct diff_filespec *two,
3092                         struct strbuf *msg,
3093                         struct diff_options *o,
3094                         struct diff_filepair *p)
3095{
3096        const char *xfrm_msg = NULL;
3097        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3098        int must_show_header = 0;
3099
3100
3101        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3102                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3103                if (drv && drv->external)
3104                        pgm = drv->external;
3105        }
3106
3107        if (msg) {
3108                /*
3109                 * don't use colors when the header is intended for an
3110                 * external diff driver
3111                 */
3112                fill_metainfo(msg, name, other, one, two, o, p,
3113                              &must_show_header,
3114                              want_color(o->use_color) && !pgm);
3115                xfrm_msg = msg->len ? msg->buf : NULL;
3116        }
3117
3118        if (pgm) {
3119                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3120                                  complete_rewrite, o);
3121                return;
3122        }
3123        if (one && two)
3124                builtin_diff(name, other ? other : name,
3125                             one, two, xfrm_msg, must_show_header,
3126                             o, complete_rewrite);
3127        else
3128                fprintf(o->file, "* Unmerged path %s\n", name);
3129}
3130
3131static void diff_fill_sha1_info(struct diff_filespec *one)
3132{
3133        if (DIFF_FILE_VALID(one)) {
3134                if (!one->oid_valid) {
3135                        struct stat st;
3136                        if (one->is_stdin) {
3137                                oidclr(&one->oid);
3138                                return;
3139                        }
3140                        if (lstat(one->path, &st) < 0)
3141                                die_errno("stat '%s'", one->path);
3142                        if (index_path(one->oid.hash, one->path, &st, 0))
3143                                die("cannot hash %s", one->path);
3144                }
3145        }
3146        else
3147                oidclr(&one->oid);
3148}
3149
3150static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3151{
3152        /* Strip the prefix but do not molest /dev/null and absolute paths */
3153        if (*namep && **namep != '/') {
3154                *namep += prefix_length;
3155                if (**namep == '/')
3156                        ++*namep;
3157        }
3158        if (*otherp && **otherp != '/') {
3159                *otherp += prefix_length;
3160                if (**otherp == '/')
3161                        ++*otherp;
3162        }
3163}
3164
3165static void run_diff(struct diff_filepair *p, struct diff_options *o)
3166{
3167        const char *pgm = external_diff();
3168        struct strbuf msg;
3169        struct diff_filespec *one = p->one;
3170        struct diff_filespec *two = p->two;
3171        const char *name;
3172        const char *other;
3173        const char *attr_path;
3174
3175        name  = p->one->path;
3176        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3177        attr_path = name;
3178        if (o->prefix_length)
3179                strip_prefix(o->prefix_length, &name, &other);
3180
3181        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3182                pgm = NULL;
3183
3184        if (DIFF_PAIR_UNMERGED(p)) {
3185                run_diff_cmd(pgm, name, NULL, attr_path,
3186                             NULL, NULL, NULL, o, p);
3187                return;
3188        }
3189
3190        diff_fill_sha1_info(one);
3191        diff_fill_sha1_info(two);
3192
3193        if (!pgm &&
3194            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3195            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3196                /*
3197                 * a filepair that changes between file and symlink
3198                 * needs to be split into deletion and creation.
3199                 */
3200                struct diff_filespec *null = alloc_filespec(two->path);
3201                run_diff_cmd(NULL, name, other, attr_path,
3202                             one, null, &msg, o, p);
3203                free(null);
3204                strbuf_release(&msg);
3205
3206                null = alloc_filespec(one->path);
3207                run_diff_cmd(NULL, name, other, attr_path,
3208                             null, two, &msg, o, p);
3209                free(null);
3210        }
3211        else
3212                run_diff_cmd(pgm, name, other, attr_path,
3213                             one, two, &msg, o, p);
3214
3215        strbuf_release(&msg);
3216}
3217
3218static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3219                         struct diffstat_t *diffstat)
3220{
3221        const char *name;
3222        const char *other;
3223
3224        if (DIFF_PAIR_UNMERGED(p)) {
3225                /* unmerged */
3226                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3227                return;
3228        }
3229
3230        name = p->one->path;
3231        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3232
3233        if (o->prefix_length)
3234                strip_prefix(o->prefix_length, &name, &other);
3235
3236        diff_fill_sha1_info(p->one);
3237        diff_fill_sha1_info(p->two);
3238
3239        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3240}
3241
3242static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3243{
3244        const char *name;
3245        const char *other;
3246        const char *attr_path;
3247
3248        if (DIFF_PAIR_UNMERGED(p)) {
3249                /* unmerged */
3250                return;
3251        }
3252
3253        name = p->one->path;
3254        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3255        attr_path = other ? other : name;
3256
3257        if (o->prefix_length)
3258                strip_prefix(o->prefix_length, &name, &other);
3259
3260        diff_fill_sha1_info(p->one);
3261        diff_fill_sha1_info(p->two);
3262
3263        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3264}
3265
3266void diff_setup(struct diff_options *options)
3267{
3268        memcpy(options, &default_diff_options, sizeof(*options));
3269
3270        options->file = stdout;
3271
3272        options->line_termination = '\n';
3273        options->break_opt = -1;
3274        options->rename_limit = -1;
3275        options->dirstat_permille = diff_dirstat_permille_default;
3276        options->context = diff_context_default;
3277        options->ws_error_highlight = WSEH_NEW;
3278        DIFF_OPT_SET(options, RENAME_EMPTY);
3279
3280        /* pathchange left =NULL by default */
3281        options->change = diff_change;
3282        options->add_remove = diff_addremove;
3283        options->use_color = diff_use_color_default;
3284        options->detect_rename = diff_detect_rename_default;
3285        options->xdl_opts |= diff_algorithm;
3286        if (diff_compaction_heuristic)
3287                DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
3288
3289        options->orderfile = diff_order_file_cfg;
3290
3291        if (diff_no_prefix) {
3292                options->a_prefix = options->b_prefix = "";
3293        } else if (!diff_mnemonic_prefix) {
3294                options->a_prefix = "a/";
3295                options->b_prefix = "b/";
3296        }
3297}
3298
3299void diff_setup_done(struct diff_options *options)
3300{
3301        int count = 0;
3302
3303        if (options->set_default)
3304                options->set_default(options);
3305
3306        if (options->output_format & DIFF_FORMAT_NAME)
3307                count++;
3308        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3309                count++;
3310        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3311                count++;
3312        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3313                count++;
3314        if (count > 1)
3315                die("--name-only, --name-status, --check and -s are mutually exclusive");
3316
3317        /*
3318         * Most of the time we can say "there are changes"
3319         * only by checking if there are changed paths, but
3320         * --ignore-whitespace* options force us to look
3321         * inside contents.
3322         */
3323
3324        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3325            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3326            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3327                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3328        else
3329                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3330
3331        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3332                options->detect_rename = DIFF_DETECT_COPY;
3333
3334        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3335                options->prefix = NULL;
3336        if (options->prefix)
3337                options->prefix_length = strlen(options->prefix);
3338        else
3339                options->prefix_length = 0;
3340
3341        if (options->output_format & (DIFF_FORMAT_NAME |
3342                                      DIFF_FORMAT_NAME_STATUS |
3343                                      DIFF_FORMAT_CHECKDIFF |
3344                                      DIFF_FORMAT_NO_OUTPUT))
3345                options->output_format &= ~(DIFF_FORMAT_RAW |
3346                                            DIFF_FORMAT_NUMSTAT |
3347                                            DIFF_FORMAT_DIFFSTAT |
3348                                            DIFF_FORMAT_SHORTSTAT |
3349                                            DIFF_FORMAT_DIRSTAT |
3350                                            DIFF_FORMAT_SUMMARY |
3351                                            DIFF_FORMAT_PATCH);
3352
3353        /*
3354         * These cases always need recursive; we do not drop caller-supplied
3355         * recursive bits for other formats here.
3356         */
3357        if (options->output_format & (DIFF_FORMAT_PATCH |
3358                                      DIFF_FORMAT_NUMSTAT |
3359                                      DIFF_FORMAT_DIFFSTAT |
3360                                      DIFF_FORMAT_SHORTSTAT |
3361                                      DIFF_FORMAT_DIRSTAT |
3362                                      DIFF_FORMAT_SUMMARY |
3363                                      DIFF_FORMAT_CHECKDIFF))
3364                DIFF_OPT_SET(options, RECURSIVE);
3365        /*
3366         * Also pickaxe would not work very well if you do not say recursive
3367         */
3368        if (options->pickaxe)
3369                DIFF_OPT_SET(options, RECURSIVE);
3370        /*
3371         * When patches are generated, submodules diffed against the work tree
3372         * must be checked for dirtiness too so it can be shown in the output
3373         */
3374        if (options->output_format & DIFF_FORMAT_PATCH)
3375                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3376
3377        if (options->detect_rename && options->rename_limit < 0)
3378                options->rename_limit = diff_rename_limit_default;
3379        if (options->setup & DIFF_SETUP_USE_CACHE) {
3380                if (!active_cache)
3381                        /* read-cache does not die even when it fails
3382                         * so it is safe for us to do this here.  Also
3383                         * it does not smudge active_cache or active_nr
3384                         * when it fails, so we do not have to worry about
3385                         * cleaning it up ourselves either.
3386                         */
3387                        read_cache();
3388        }
3389        if (options->abbrev <= 0 || 40 < options->abbrev)
3390                options->abbrev = 40; /* full */
3391
3392        /*
3393         * It does not make sense to show the first hit we happened
3394         * to have found.  It does not make sense not to return with
3395         * exit code in such a case either.
3396         */
3397        if (DIFF_OPT_TST(options, QUICK)) {
3398                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3399                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3400        }
3401
3402        options->diff_path_counter = 0;
3403
3404        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3405                die(_("--follow requires exactly one pathspec"));
3406}
3407
3408static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3409{
3410        char c, *eq;
3411        int len;
3412
3413        if (*arg != '-')
3414                return 0;
3415        c = *++arg;
3416        if (!c)
3417                return 0;
3418        if (c == arg_short) {
3419                c = *++arg;
3420                if (!c)
3421                        return 1;
3422                if (val && isdigit(c)) {
3423                        char *end;
3424                        int n = strtoul(arg, &end, 10);
3425                        if (*end)
3426                                return 0;
3427                        *val = n;
3428                        return 1;
3429                }
3430                return 0;
3431        }
3432        if (c != '-')
3433                return 0;
3434        arg++;
3435        eq = strchrnul(arg, '=');
3436        len = eq - arg;
3437        if (!len || strncmp(arg, arg_long, len))
3438                return 0;
3439        if (*eq) {
3440                int n;
3441                char *end;
3442                if (!isdigit(*++eq))
3443                        return 0;
3444                n = strtoul(eq, &end, 10);
3445                if (*end)
3446                        return 0;
3447                *val = n;
3448        }
3449        return 1;
3450}
3451
3452static int diff_scoreopt_parse(const char *opt);
3453
3454static inline int short_opt(char opt, const char **argv,
3455                            const char **optarg)
3456{
3457        const char *arg = argv[0];
3458        if (arg[0] != '-' || arg[1] != opt)
3459                return 0;
3460        if (arg[2] != '\0') {
3461                *optarg = arg + 2;
3462                return 1;
3463        }
3464        if (!argv[1])
3465                die("Option '%c' requires a value", opt);
3466        *optarg = argv[1];
3467        return 2;
3468}
3469
3470int parse_long_opt(const char *opt, const char **argv,
3471                   const char **optarg)
3472{
3473        const char *arg = argv[0];
3474        if (!skip_prefix(arg, "--", &arg))
3475                return 0;
3476        if (!skip_prefix(arg, opt, &arg))
3477                return 0;
3478        if (*arg == '=') { /* stuck form: --option=value */
3479                *optarg = arg + 1;
3480                return 1;
3481        }
3482        if (*arg != '\0')
3483                return 0;
3484        /* separate form: --option value */
3485        if (!argv[1])
3486                die("Option '--%s' requires a value", opt);
3487        *optarg = argv[1];
3488        return 2;
3489}
3490
3491static int stat_opt(struct diff_options *options, const char **av)
3492{
3493        const char *arg = av[0];
3494        char *end;
3495        int width = options->stat_width;
3496        int name_width = options->stat_name_width;
3497        int graph_width = options->stat_graph_width;
3498        int count = options->stat_count;
3499        int argcount = 1;
3500
3501        if (!skip_prefix(arg, "--stat", &arg))
3502                die("BUG: stat option does not begin with --stat: %s", arg);
3503        end = (char *)arg;
3504
3505        switch (*arg) {
3506        case '-':
3507                if (skip_prefix(arg, "-width", &arg)) {
3508                        if (*arg == '=')
3509                                width = strtoul(arg + 1, &end, 10);
3510                        else if (!*arg && !av[1])
3511                                die("Option '--stat-width' requires a value");
3512                        else if (!*arg) {
3513                                width = strtoul(av[1], &end, 10);
3514                                argcount = 2;
3515                        }
3516                } else if (skip_prefix(arg, "-name-width", &arg)) {
3517                        if (*arg == '=')
3518                                name_width = strtoul(arg + 1, &end, 10);
3519                        else if (!*arg && !av[1])
3520                                die("Option '--stat-name-width' requires a value");
3521                        else if (!*arg) {
3522                                name_width = strtoul(av[1], &end, 10);
3523                                argcount = 2;
3524                        }
3525                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3526                        if (*arg == '=')
3527                                graph_width = strtoul(arg + 1, &end, 10);
3528                        else if (!*arg && !av[1])
3529                                die("Option '--stat-graph-width' requires a value");
3530                        else if (!*arg) {
3531                                graph_width = strtoul(av[1], &end, 10);
3532                                argcount = 2;
3533                        }
3534                } else if (skip_prefix(arg, "-count", &arg)) {
3535                        if (*arg == '=')
3536                                count = strtoul(arg + 1, &end, 10);
3537                        else if (!*arg && !av[1])
3538                                die("Option '--stat-count' requires a value");
3539                        else if (!*arg) {
3540                                count = strtoul(av[1], &end, 10);
3541                                argcount = 2;
3542                        }
3543                }
3544                break;
3545        case '=':
3546                width = strtoul(arg+1, &end, 10);
3547                if (*end == ',')
3548                        name_width = strtoul(end+1, &end, 10);
3549                if (*end == ',')
3550                        count = strtoul(end+1, &end, 10);
3551        }
3552
3553        /* Important! This checks all the error cases! */
3554        if (*end)
3555                return 0;
3556        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3557        options->stat_name_width = name_width;
3558        options->stat_graph_width = graph_width;
3559        options->stat_width = width;
3560        options->stat_count = count;
3561        return argcount;
3562}
3563
3564static int parse_dirstat_opt(struct diff_options *options, const char *params)
3565{
3566        struct strbuf errmsg = STRBUF_INIT;
3567        if (parse_dirstat_params(options, params, &errmsg))
3568                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3569                    errmsg.buf);
3570        strbuf_release(&errmsg);
3571        /*
3572         * The caller knows a dirstat-related option is given from the command
3573         * line; allow it to say "return this_function();"
3574         */
3575        options->output_format |= DIFF_FORMAT_DIRSTAT;
3576        return 1;
3577}
3578
3579static int parse_submodule_opt(struct diff_options *options, const char *value)
3580{
3581        if (parse_submodule_params(options, value))
3582                die(_("Failed to parse --submodule option parameter: '%s'"),
3583                        value);
3584        return 1;
3585}
3586
3587static const char diff_status_letters[] = {
3588        DIFF_STATUS_ADDED,
3589        DIFF_STATUS_COPIED,
3590        DIFF_STATUS_DELETED,
3591        DIFF_STATUS_MODIFIED,
3592        DIFF_STATUS_RENAMED,
3593        DIFF_STATUS_TYPE_CHANGED,
3594        DIFF_STATUS_UNKNOWN,
3595        DIFF_STATUS_UNMERGED,
3596        DIFF_STATUS_FILTER_AON,
3597        DIFF_STATUS_FILTER_BROKEN,
3598        '\0',
3599};
3600
3601static unsigned int filter_bit['Z' + 1];
3602
3603static void prepare_filter_bits(void)
3604{
3605        int i;
3606
3607        if (!filter_bit[DIFF_STATUS_ADDED]) {
3608                for (i = 0; diff_status_letters[i]; i++)
3609                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3610        }
3611}
3612
3613static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3614{
3615        return opt->filter & filter_bit[(int) status];
3616}
3617
3618static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3619{
3620        int i, optch;
3621
3622        prepare_filter_bits();
3623
3624        /*
3625         * If there is a negation e.g. 'd' in the input, and we haven't
3626         * initialized the filter field with another --diff-filter, start
3627         * from full set of bits, except for AON.
3628         */
3629        if (!opt->filter) {
3630                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3631                        if (optch < 'a' || 'z' < optch)
3632                                continue;
3633                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3634                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3635                        break;
3636                }
3637        }
3638
3639        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3640                unsigned int bit;
3641                int negate;
3642
3643                if ('a' <= optch && optch <= 'z') {
3644                        negate = 1;
3645                        optch = toupper(optch);
3646                } else {
3647                        negate = 0;
3648                }
3649
3650                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3651                if (!bit)
3652                        return optarg[i];
3653                if (negate)
3654                        opt->filter &= ~bit;
3655                else
3656                        opt->filter |= bit;
3657        }
3658        return 0;
3659}
3660
3661static void enable_patch_output(int *fmt) {
3662        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3663        *fmt |= DIFF_FORMAT_PATCH;
3664}
3665
3666static int parse_one_token(const char **arg, const char *token)
3667{
3668        const char *rest;
3669        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3670                *arg = rest;
3671                return 1;
3672        }
3673        return 0;
3674}
3675
3676static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3677{
3678        const char *orig_arg = arg;
3679        unsigned val = 0;
3680        while (*arg) {
3681                if (parse_one_token(&arg, "none"))
3682                        val = 0;
3683                else if (parse_one_token(&arg, "default"))
3684                        val = WSEH_NEW;
3685                else if (parse_one_token(&arg, "all"))
3686                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3687                else if (parse_one_token(&arg, "new"))
3688                        val |= WSEH_NEW;
3689                else if (parse_one_token(&arg, "old"))
3690                        val |= WSEH_OLD;
3691                else if (parse_one_token(&arg, "context"))
3692                        val |= WSEH_CONTEXT;
3693                else {
3694                        error("unknown value after ws-error-highlight=%.*s",
3695                              (int)(arg - orig_arg), orig_arg);
3696                        return 0;
3697                }
3698                if (*arg)
3699                        arg++;
3700        }
3701        opt->ws_error_highlight = val;
3702        return 1;
3703}
3704
3705int diff_opt_parse(struct diff_options *options,
3706                   const char **av, int ac, const char *prefix)
3707{
3708        const char *arg = av[0];
3709        const char *optarg;
3710        int argcount;
3711
3712        if (!prefix)
3713                prefix = "";
3714
3715        /* Output format options */
3716        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3717            || opt_arg(arg, 'U', "unified", &options->context))
3718                enable_patch_output(&options->output_format);
3719        else if (!strcmp(arg, "--raw"))
3720                options->output_format |= DIFF_FORMAT_RAW;
3721        else if (!strcmp(arg, "--patch-with-raw")) {
3722                enable_patch_output(&options->output_format);
3723                options->output_format |= DIFF_FORMAT_RAW;
3724        } else if (!strcmp(arg, "--numstat"))
3725                options->output_format |= DIFF_FORMAT_NUMSTAT;
3726        else if (!strcmp(arg, "--shortstat"))
3727                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3728        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3729                return parse_dirstat_opt(options, "");
3730        else if (skip_prefix(arg, "-X", &arg))
3731                return parse_dirstat_opt(options, arg);
3732        else if (skip_prefix(arg, "--dirstat=", &arg))
3733                return parse_dirstat_opt(options, arg);
3734        else if (!strcmp(arg, "--cumulative"))
3735                return parse_dirstat_opt(options, "cumulative");
3736        else if (!strcmp(arg, "--dirstat-by-file"))
3737                return parse_dirstat_opt(options, "files");
3738        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3739                parse_dirstat_opt(options, "files");
3740                return parse_dirstat_opt(options, arg);
3741        }
3742        else if (!strcmp(arg, "--check"))
3743                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3744        else if (!strcmp(arg, "--summary"))
3745                options->output_format |= DIFF_FORMAT_SUMMARY;
3746        else if (!strcmp(arg, "--patch-with-stat")) {
3747                enable_patch_output(&options->output_format);
3748                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3749        } else if (!strcmp(arg, "--name-only"))
3750                options->output_format |= DIFF_FORMAT_NAME;
3751        else if (!strcmp(arg, "--name-status"))
3752                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3753        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3754                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3755        else if (starts_with(arg, "--stat"))
3756                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3757                return stat_opt(options, av);
3758
3759        /* renames options */
3760        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3761                 !strcmp(arg, "--break-rewrites")) {
3762                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3763                        return error("invalid argument to -B: %s", arg+2);
3764        }
3765        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3766                 !strcmp(arg, "--find-renames")) {
3767                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3768                        return error("invalid argument to -M: %s", arg+2);
3769                options->detect_rename = DIFF_DETECT_RENAME;
3770        }
3771        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3772                options->irreversible_delete = 1;
3773        }
3774        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3775                 !strcmp(arg, "--find-copies")) {
3776                if (options->detect_rename == DIFF_DETECT_COPY)
3777                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3778                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3779                        return error("invalid argument to -C: %s", arg+2);
3780                options->detect_rename = DIFF_DETECT_COPY;
3781        }
3782        else if (!strcmp(arg, "--no-renames"))
3783                options->detect_rename = 0;
3784        else if (!strcmp(arg, "--rename-empty"))
3785                DIFF_OPT_SET(options, RENAME_EMPTY);
3786        else if (!strcmp(arg, "--no-rename-empty"))
3787                DIFF_OPT_CLR(options, RENAME_EMPTY);
3788        else if (!strcmp(arg, "--relative"))
3789                DIFF_OPT_SET(options, RELATIVE_NAME);
3790        else if (skip_prefix(arg, "--relative=", &arg)) {
3791                DIFF_OPT_SET(options, RELATIVE_NAME);
3792                options->prefix = arg;
3793        }
3794
3795        /* xdiff options */
3796        else if (!strcmp(arg, "--minimal"))
3797                DIFF_XDL_SET(options, NEED_MINIMAL);
3798        else if (!strcmp(arg, "--no-minimal"))
3799                DIFF_XDL_CLR(options, NEED_MINIMAL);
3800        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3801                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3802        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3803                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3804        else if (!strcmp(arg, "--ignore-space-at-eol"))
3805                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3806        else if (!strcmp(arg, "--ignore-blank-lines"))
3807                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3808        else if (!strcmp(arg, "--compaction-heuristic"))
3809                DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
3810        else if (!strcmp(arg, "--no-compaction-heuristic"))
3811                DIFF_XDL_CLR(options, COMPACTION_HEURISTIC);
3812        else if (!strcmp(arg, "--patience"))
3813                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3814        else if (!strcmp(arg, "--histogram"))
3815                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3816        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3817                long value = parse_algorithm_value(optarg);
3818                if (value < 0)
3819                        return error("option diff-algorithm accepts \"myers\", "
3820                                     "\"minimal\", \"patience\" and \"histogram\"");
3821                /* clear out previous settings */
3822                DIFF_XDL_CLR(options, NEED_MINIMAL);
3823                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3824                options->xdl_opts |= value;
3825                return argcount;
3826        }
3827
3828        /* flags options */
3829        else if (!strcmp(arg, "--binary")) {
3830                enable_patch_output(&options->output_format);
3831                DIFF_OPT_SET(options, BINARY);
3832        }
3833        else if (!strcmp(arg, "--full-index"))
3834                DIFF_OPT_SET(options, FULL_INDEX);
3835        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3836                DIFF_OPT_SET(options, TEXT);
3837        else if (!strcmp(arg, "-R"))
3838                DIFF_OPT_SET(options, REVERSE_DIFF);
3839        else if (!strcmp(arg, "--find-copies-harder"))
3840                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3841        else if (!strcmp(arg, "--follow"))
3842                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3843        else if (!strcmp(arg, "--no-follow")) {
3844                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3845                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3846        } else if (!strcmp(arg, "--color"))
3847                options->use_color = 1;
3848        else if (skip_prefix(arg, "--color=", &arg)) {
3849                int value = git_config_colorbool(NULL, arg);
3850                if (value < 0)
3851                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3852                options->use_color = value;
3853        }
3854        else if (!strcmp(arg, "--no-color"))
3855                options->use_color = 0;
3856        else if (!strcmp(arg, "--color-words")) {
3857                options->use_color = 1;
3858                options->word_diff = DIFF_WORDS_COLOR;
3859        }
3860        else if (skip_prefix(arg, "--color-words=", &arg)) {
3861                options->use_color = 1;
3862                options->word_diff = DIFF_WORDS_COLOR;
3863                options->word_regex = arg;
3864        }
3865        else if (!strcmp(arg, "--word-diff")) {
3866                if (options->word_diff == DIFF_WORDS_NONE)
3867                        options->word_diff = DIFF_WORDS_PLAIN;
3868        }
3869        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3870                if (!strcmp(arg, "plain"))
3871                        options->word_diff = DIFF_WORDS_PLAIN;
3872                else if (!strcmp(arg, "color")) {
3873                        options->use_color = 1;
3874                        options->word_diff = DIFF_WORDS_COLOR;
3875                }
3876                else if (!strcmp(arg, "porcelain"))
3877                        options->word_diff = DIFF_WORDS_PORCELAIN;
3878                else if (!strcmp(arg, "none"))
3879                        options->word_diff = DIFF_WORDS_NONE;
3880                else
3881                        die("bad --word-diff argument: %s", arg);
3882        }
3883        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3884                if (options->word_diff == DIFF_WORDS_NONE)
3885                        options->word_diff = DIFF_WORDS_PLAIN;
3886                options->word_regex = optarg;
3887                return argcount;
3888        }
3889        else if (!strcmp(arg, "--exit-code"))
3890                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3891        else if (!strcmp(arg, "--quiet"))
3892                DIFF_OPT_SET(options, QUICK);
3893        else if (!strcmp(arg, "--ext-diff"))
3894                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3895        else if (!strcmp(arg, "--no-ext-diff"))
3896                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3897        else if (!strcmp(arg, "--textconv"))
3898                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3899        else if (!strcmp(arg, "--no-textconv"))
3900                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3901        else if (!strcmp(arg, "--ignore-submodules")) {
3902                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3903                handle_ignore_submodules_arg(options, "all");
3904        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3905                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3906                handle_ignore_submodules_arg(options, arg);
3907        } else if (!strcmp(arg, "--submodule"))
3908                DIFF_OPT_SET(options, SUBMODULE_LOG);
3909        else if (skip_prefix(arg, "--submodule=", &arg))
3910                return parse_submodule_opt(options, arg);
3911        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3912                return parse_ws_error_highlight(options, arg);
3913
3914        /* misc options */
3915        else if (!strcmp(arg, "-z"))
3916                options->line_termination = 0;
3917        else if ((argcount = short_opt('l', av, &optarg))) {
3918                options->rename_limit = strtoul(optarg, NULL, 10);
3919                return argcount;
3920        }
3921        else if ((argcount = short_opt('S', av, &optarg))) {
3922                options->pickaxe = optarg;
3923                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3924                return argcount;
3925        } else if ((argcount = short_opt('G', av, &optarg))) {
3926                options->pickaxe = optarg;
3927                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3928                return argcount;
3929        }
3930        else if (!strcmp(arg, "--pickaxe-all"))
3931                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3932        else if (!strcmp(arg, "--pickaxe-regex"))
3933                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3934        else if ((argcount = short_opt('O', av, &optarg))) {
3935                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3936                options->orderfile = xstrdup(path);
3937                return argcount;
3938        }
3939        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3940                int offending = parse_diff_filter_opt(optarg, options);
3941                if (offending)
3942                        die("unknown change class '%c' in --diff-filter=%s",
3943                            offending, optarg);
3944                return argcount;
3945        }
3946        else if (!strcmp(arg, "--abbrev"))
3947                options->abbrev = DEFAULT_ABBREV;
3948        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3949                options->abbrev = strtoul(arg, NULL, 10);
3950                if (options->abbrev < MINIMUM_ABBREV)
3951                        options->abbrev = MINIMUM_ABBREV;
3952                else if (40 < options->abbrev)
3953                        options->abbrev = 40;
3954        }
3955        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3956                options->a_prefix = optarg;
3957                return argcount;
3958        }
3959        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3960                options->b_prefix = optarg;
3961                return argcount;
3962        }
3963        else if (!strcmp(arg, "--no-prefix"))
3964                options->a_prefix = options->b_prefix = "";
3965        else if (opt_arg(arg, '\0', "inter-hunk-context",
3966                         &options->interhunkcontext))
3967                ;
3968        else if (!strcmp(arg, "-W"))
3969                DIFF_OPT_SET(options, FUNCCONTEXT);
3970        else if (!strcmp(arg, "--function-context"))
3971                DIFF_OPT_SET(options, FUNCCONTEXT);
3972        else if (!strcmp(arg, "--no-function-context"))
3973                DIFF_OPT_CLR(options, FUNCCONTEXT);
3974        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3975                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3976                options->file = fopen(path, "w");
3977                if (!options->file)
3978                        die_errno("Could not open '%s'", path);
3979                options->close_file = 1;
3980                if (options->use_color != GIT_COLOR_ALWAYS)
3981                        options->use_color = GIT_COLOR_NEVER;
3982                return argcount;
3983        } else
3984                return 0;
3985        return 1;
3986}
3987
3988int parse_rename_score(const char **cp_p)
3989{
3990        unsigned long num, scale;
3991        int ch, dot;
3992        const char *cp = *cp_p;
3993
3994        num = 0;
3995        scale = 1;
3996        dot = 0;
3997        for (;;) {
3998                ch = *cp;
3999                if ( !dot && ch == '.' ) {
4000                        scale = 1;
4001                        dot = 1;
4002                } else if ( ch == '%' ) {
4003                        scale = dot ? scale*100 : 100;
4004                        cp++;   /* % is always at the end */
4005                        break;
4006                } else if ( ch >= '0' && ch <= '9' ) {
4007                        if ( scale < 100000 ) {
4008                                scale *= 10;
4009                                num = (num*10) + (ch-'0');
4010                        }
4011                } else {
4012                        break;
4013                }
4014                cp++;
4015        }
4016        *cp_p = cp;
4017
4018        /* user says num divided by scale and we say internally that
4019         * is MAX_SCORE * num / scale.
4020         */
4021        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4022}
4023
4024static int diff_scoreopt_parse(const char *opt)
4025{
4026        int opt1, opt2, cmd;
4027
4028        if (*opt++ != '-')
4029                return -1;
4030        cmd = *opt++;
4031        if (cmd == '-') {
4032                /* convert the long-form arguments into short-form versions */
4033                if (skip_prefix(opt, "break-rewrites", &opt)) {
4034                        if (*opt == 0 || *opt++ == '=')
4035                                cmd = 'B';
4036                } else if (skip_prefix(opt, "find-copies", &opt)) {
4037                        if (*opt == 0 || *opt++ == '=')
4038                                cmd = 'C';
4039                } else if (skip_prefix(opt, "find-renames", &opt)) {
4040                        if (*opt == 0 || *opt++ == '=')
4041                                cmd = 'M';
4042                }
4043        }
4044        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4045                return -1; /* that is not a -M, -C, or -B option */
4046
4047        opt1 = parse_rename_score(&opt);
4048        if (cmd != 'B')
4049                opt2 = 0;
4050        else {
4051                if (*opt == 0)
4052                        opt2 = 0;
4053                else if (*opt != '/')
4054                        return -1; /* we expect -B80/99 or -B80 */
4055                else {
4056                        opt++;
4057                        opt2 = parse_rename_score(&opt);
4058                }
4059        }
4060        if (*opt != 0)
4061                return -1;
4062        return opt1 | (opt2 << 16);
4063}
4064
4065struct diff_queue_struct diff_queued_diff;
4066
4067void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4068{
4069        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4070        queue->queue[queue->nr++] = dp;
4071}
4072
4073struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4074                                 struct diff_filespec *one,
4075                                 struct diff_filespec *two)
4076{
4077        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4078        dp->one = one;
4079        dp->two = two;
4080        if (queue)
4081                diff_q(queue, dp);
4082        return dp;
4083}
4084
4085void diff_free_filepair(struct diff_filepair *p)
4086{
4087        free_filespec(p->one);
4088        free_filespec(p->two);
4089        free(p);
4090}
4091
4092/* This is different from find_unique_abbrev() in that
4093 * it stuffs the result with dots for alignment.
4094 */
4095const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4096{
4097        int abblen;
4098        const char *abbrev;
4099        if (len == 40)
4100                return sha1_to_hex(sha1);
4101
4102        abbrev = find_unique_abbrev(sha1, len);
4103        abblen = strlen(abbrev);
4104        if (abblen < 37) {
4105                static char hex[41];
4106                if (len < abblen && abblen <= len + 2)
4107                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4108                else
4109                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4110                return hex;
4111        }
4112        return sha1_to_hex(sha1);
4113}
4114
4115static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4116{
4117        int line_termination = opt->line_termination;
4118        int inter_name_termination = line_termination ? '\t' : '\0';
4119
4120        fprintf(opt->file, "%s", diff_line_prefix(opt));
4121        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4122                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4123                        diff_unique_abbrev(p->one->oid.hash, opt->abbrev));
4124                fprintf(opt->file, "%s ",
4125                        diff_unique_abbrev(p->two->oid.hash, opt->abbrev));
4126        }
4127        if (p->score) {
4128                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4129                        inter_name_termination);
4130        } else {
4131                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4132        }
4133
4134        if (p->status == DIFF_STATUS_COPIED ||
4135            p->status == DIFF_STATUS_RENAMED) {
4136                const char *name_a, *name_b;
4137                name_a = p->one->path;
4138                name_b = p->two->path;
4139                strip_prefix(opt->prefix_length, &name_a, &name_b);
4140                write_name_quoted(name_a, opt->file, inter_name_termination);
4141                write_name_quoted(name_b, opt->file, line_termination);
4142        } else {
4143                const char *name_a, *name_b;
4144                name_a = p->one->mode ? p->one->path : p->two->path;
4145                name_b = NULL;
4146                strip_prefix(opt->prefix_length, &name_a, &name_b);
4147                write_name_quoted(name_a, opt->file, line_termination);
4148        }
4149}
4150
4151int diff_unmodified_pair(struct diff_filepair *p)
4152{
4153        /* This function is written stricter than necessary to support
4154         * the currently implemented transformers, but the idea is to
4155         * let transformers to produce diff_filepairs any way they want,
4156         * and filter and clean them up here before producing the output.
4157         */
4158        struct diff_filespec *one = p->one, *two = p->two;
4159
4160        if (DIFF_PAIR_UNMERGED(p))
4161                return 0; /* unmerged is interesting */
4162
4163        /* deletion, addition, mode or type change
4164         * and rename are all interesting.
4165         */
4166        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4167            DIFF_PAIR_MODE_CHANGED(p) ||
4168            strcmp(one->path, two->path))
4169                return 0;
4170
4171        /* both are valid and point at the same path.  that is, we are
4172         * dealing with a change.
4173         */
4174        if (one->oid_valid && two->oid_valid &&
4175            !oidcmp(&one->oid, &two->oid) &&
4176            !one->dirty_submodule && !two->dirty_submodule)
4177                return 1; /* no change */
4178        if (!one->oid_valid && !two->oid_valid)
4179                return 1; /* both look at the same file on the filesystem. */
4180        return 0;
4181}
4182
4183static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4184{
4185        if (diff_unmodified_pair(p))
4186                return;
4187
4188        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4189            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4190                return; /* no tree diffs in patch format */
4191
4192        run_diff(p, o);
4193}
4194
4195static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4196                            struct diffstat_t *diffstat)
4197{
4198        if (diff_unmodified_pair(p))
4199                return;
4200
4201        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4202            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4203                return; /* no useful stat for tree diffs */
4204
4205        run_diffstat(p, o, diffstat);
4206}
4207
4208static void diff_flush_checkdiff(struct diff_filepair *p,
4209                struct diff_options *o)
4210{
4211        if (diff_unmodified_pair(p))
4212                return;
4213
4214        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4215            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4216                return; /* nothing to check in tree diffs */
4217
4218        run_checkdiff(p, o);
4219}
4220
4221int diff_queue_is_empty(void)
4222{
4223        struct diff_queue_struct *q = &diff_queued_diff;
4224        int i;
4225        for (i = 0; i < q->nr; i++)
4226                if (!diff_unmodified_pair(q->queue[i]))
4227                        return 0;
4228        return 1;
4229}
4230
4231#if DIFF_DEBUG
4232void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4233{
4234        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4235                x, one ? one : "",
4236                s->path,
4237                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4238                s->mode,
4239                s->oid_valid ? oid_to_hex(&s->oid) : "");
4240        fprintf(stderr, "queue[%d] %s size %lu\n",
4241                x, one ? one : "",
4242                s->size);
4243}
4244
4245void diff_debug_filepair(const struct diff_filepair *p, int i)
4246{
4247        diff_debug_filespec(p->one, i, "one");
4248        diff_debug_filespec(p->two, i, "two");
4249        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4250                p->score, p->status ? p->status : '?',
4251                p->one->rename_used, p->broken_pair);
4252}
4253
4254void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4255{
4256        int i;
4257        if (msg)
4258                fprintf(stderr, "%s\n", msg);
4259        fprintf(stderr, "q->nr = %d\n", q->nr);
4260        for (i = 0; i < q->nr; i++) {
4261                struct diff_filepair *p = q->queue[i];
4262                diff_debug_filepair(p, i);
4263        }
4264}
4265#endif
4266
4267static void diff_resolve_rename_copy(void)
4268{
4269        int i;
4270        struct diff_filepair *p;
4271        struct diff_queue_struct *q = &diff_queued_diff;
4272
4273        diff_debug_queue("resolve-rename-copy", q);
4274
4275        for (i = 0; i < q->nr; i++) {
4276                p = q->queue[i];
4277                p->status = 0; /* undecided */
4278                if (DIFF_PAIR_UNMERGED(p))
4279                        p->status = DIFF_STATUS_UNMERGED;
4280                else if (!DIFF_FILE_VALID(p->one))
4281                        p->status = DIFF_STATUS_ADDED;
4282                else if (!DIFF_FILE_VALID(p->two))
4283                        p->status = DIFF_STATUS_DELETED;
4284                else if (DIFF_PAIR_TYPE_CHANGED(p))
4285                        p->status = DIFF_STATUS_TYPE_CHANGED;
4286
4287                /* from this point on, we are dealing with a pair
4288                 * whose both sides are valid and of the same type, i.e.
4289                 * either in-place edit or rename/copy edit.
4290                 */
4291                else if (DIFF_PAIR_RENAME(p)) {
4292                        /*
4293                         * A rename might have re-connected a broken
4294                         * pair up, causing the pathnames to be the
4295                         * same again. If so, that's not a rename at
4296                         * all, just a modification..
4297                         *
4298                         * Otherwise, see if this source was used for
4299                         * multiple renames, in which case we decrement
4300                         * the count, and call it a copy.
4301                         */
4302                        if (!strcmp(p->one->path, p->two->path))
4303                                p->status = DIFF_STATUS_MODIFIED;
4304                        else if (--p->one->rename_used > 0)
4305                                p->status = DIFF_STATUS_COPIED;
4306                        else
4307                                p->status = DIFF_STATUS_RENAMED;
4308                }
4309                else if (oidcmp(&p->one->oid, &p->two->oid) ||
4310                         p->one->mode != p->two->mode ||
4311                         p->one->dirty_submodule ||
4312                         p->two->dirty_submodule ||
4313                         is_null_oid(&p->one->oid))
4314                        p->status = DIFF_STATUS_MODIFIED;
4315                else {
4316                        /* This is a "no-change" entry and should not
4317                         * happen anymore, but prepare for broken callers.
4318                         */
4319                        error("feeding unmodified %s to diffcore",
4320                              p->one->path);
4321                        p->status = DIFF_STATUS_UNKNOWN;
4322                }
4323        }
4324        diff_debug_queue("resolve-rename-copy done", q);
4325}
4326
4327static int check_pair_status(struct diff_filepair *p)
4328{
4329        switch (p->status) {
4330        case DIFF_STATUS_UNKNOWN:
4331                return 0;
4332        case 0:
4333                die("internal error in diff-resolve-rename-copy");
4334        default:
4335                return 1;
4336        }
4337}
4338
4339static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4340{
4341        int fmt = opt->output_format;
4342
4343        if (fmt & DIFF_FORMAT_CHECKDIFF)
4344                diff_flush_checkdiff(p, opt);
4345        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4346                diff_flush_raw(p, opt);
4347        else if (fmt & DIFF_FORMAT_NAME) {
4348                const char *name_a, *name_b;
4349                name_a = p->two->path;
4350                name_b = NULL;
4351                strip_prefix(opt->prefix_length, &name_a, &name_b);
4352                write_name_quoted(name_a, opt->file, opt->line_termination);
4353        }
4354}
4355
4356static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4357{
4358        if (fs->mode)
4359                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4360        else
4361                fprintf(file, " %s ", newdelete);
4362        write_name_quoted(fs->path, file, '\n');
4363}
4364
4365
4366static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4367                const char *line_prefix)
4368{
4369        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4370                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4371                        p->two->mode, show_name ? ' ' : '\n');
4372                if (show_name) {
4373                        write_name_quoted(p->two->path, file, '\n');
4374                }
4375        }
4376}
4377
4378static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4379                        const char *line_prefix)
4380{
4381        char *names = pprint_rename(p->one->path, p->two->path);
4382
4383        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4384        free(names);
4385        show_mode_change(file, p, 0, line_prefix);
4386}
4387
4388static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4389{
4390        FILE *file = opt->file;
4391        const char *line_prefix = diff_line_prefix(opt);
4392
4393        switch(p->status) {
4394        case DIFF_STATUS_DELETED:
4395                fputs(line_prefix, file);
4396                show_file_mode_name(file, "delete", p->one);
4397                break;
4398        case DIFF_STATUS_ADDED:
4399                fputs(line_prefix, file);
4400                show_file_mode_name(file, "create", p->two);
4401                break;
4402        case DIFF_STATUS_COPIED:
4403                fputs(line_prefix, file);
4404                show_rename_copy(file, "copy", p, line_prefix);
4405                break;
4406        case DIFF_STATUS_RENAMED:
4407                fputs(line_prefix, file);
4408                show_rename_copy(file, "rename", p, line_prefix);
4409                break;
4410        default:
4411                if (p->score) {
4412                        fprintf(file, "%s rewrite ", line_prefix);
4413                        write_name_quoted(p->two->path, file, ' ');
4414                        fprintf(file, "(%d%%)\n", similarity_index(p));
4415                }
4416                show_mode_change(file, p, !p->score, line_prefix);
4417                break;
4418        }
4419}
4420
4421struct patch_id_t {
4422        git_SHA_CTX *ctx;
4423        int patchlen;
4424};
4425
4426static int remove_space(char *line, int len)
4427{
4428        int i;
4429        char *dst = line;
4430        unsigned char c;
4431
4432        for (i = 0; i < len; i++)
4433                if (!isspace((c = line[i])))
4434                        *dst++ = c;
4435
4436        return dst - line;
4437}
4438
4439static void patch_id_consume(void *priv, char *line, unsigned long len)
4440{
4441        struct patch_id_t *data = priv;
4442        int new_len;
4443
4444        /* Ignore line numbers when computing the SHA1 of the patch */
4445        if (starts_with(line, "@@ -"))
4446                return;
4447
4448        new_len = remove_space(line, len);
4449
4450        git_SHA1_Update(data->ctx, line, new_len);
4451        data->patchlen += new_len;
4452}
4453
4454/* returns 0 upon success, and writes result into sha1 */
4455static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4456{
4457        struct diff_queue_struct *q = &diff_queued_diff;
4458        int i;
4459        git_SHA_CTX ctx;
4460        struct patch_id_t data;
4461        char buffer[PATH_MAX * 4 + 20];
4462
4463        git_SHA1_Init(&ctx);
4464        memset(&data, 0, sizeof(struct patch_id_t));
4465        data.ctx = &ctx;
4466
4467        for (i = 0; i < q->nr; i++) {
4468                xpparam_t xpp;
4469                xdemitconf_t xecfg;
4470                mmfile_t mf1, mf2;
4471                struct diff_filepair *p = q->queue[i];
4472                int len1, len2;
4473
4474                memset(&xpp, 0, sizeof(xpp));
4475                memset(&xecfg, 0, sizeof(xecfg));
4476                if (p->status == 0)
4477                        return error("internal diff status error");
4478                if (p->status == DIFF_STATUS_UNKNOWN)
4479                        continue;
4480                if (diff_unmodified_pair(p))
4481                        continue;
4482                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4483                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4484                        continue;
4485                if (DIFF_PAIR_UNMERGED(p))
4486                        continue;
4487
4488                diff_fill_sha1_info(p->one);
4489                diff_fill_sha1_info(p->two);
4490
4491                len1 = remove_space(p->one->path, strlen(p->one->path));
4492                len2 = remove_space(p->two->path, strlen(p->two->path));
4493                if (p->one->mode == 0)
4494                        len1 = snprintf(buffer, sizeof(buffer),
4495                                        "diff--gita/%.*sb/%.*s"
4496                                        "newfilemode%06o"
4497                                        "---/dev/null"
4498                                        "+++b/%.*s",
4499                                        len1, p->one->path,
4500                                        len2, p->two->path,
4501                                        p->two->mode,
4502                                        len2, p->two->path);
4503                else if (p->two->mode == 0)
4504                        len1 = snprintf(buffer, sizeof(buffer),
4505                                        "diff--gita/%.*sb/%.*s"
4506                                        "deletedfilemode%06o"
4507                                        "---a/%.*s"
4508                                        "+++/dev/null",
4509                                        len1, p->one->path,
4510                                        len2, p->two->path,
4511                                        p->one->mode,
4512                                        len1, p->one->path);
4513                else
4514                        len1 = snprintf(buffer, sizeof(buffer),
4515                                        "diff--gita/%.*sb/%.*s"
4516                                        "---a/%.*s"
4517                                        "+++b/%.*s",
4518                                        len1, p->one->path,
4519                                        len2, p->two->path,
4520                                        len1, p->one->path,
4521                                        len2, p->two->path);
4522                git_SHA1_Update(&ctx, buffer, len1);
4523
4524                if (diff_header_only)
4525                        continue;
4526
4527                if (fill_mmfile(&mf1, p->one) < 0 ||
4528                    fill_mmfile(&mf2, p->two) < 0)
4529                        return error("unable to read files to diff");
4530
4531                if (diff_filespec_is_binary(p->one) ||
4532                    diff_filespec_is_binary(p->two)) {
4533                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4534                                        40);
4535                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4536                                        40);
4537                        continue;
4538                }
4539
4540                xpp.flags = 0;
4541                xecfg.ctxlen = 3;
4542                xecfg.flags = 0;
4543                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4544                                  &xpp, &xecfg))
4545                        return error("unable to generate patch-id diff for %s",
4546                                     p->one->path);
4547        }
4548
4549        git_SHA1_Final(sha1, &ctx);
4550        return 0;
4551}
4552
4553int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4554{
4555        struct diff_queue_struct *q = &diff_queued_diff;
4556        int i;
4557        int result = diff_get_patch_id(options, sha1, diff_header_only);
4558
4559        for (i = 0; i < q->nr; i++)
4560                diff_free_filepair(q->queue[i]);
4561
4562        free(q->queue);
4563        DIFF_QUEUE_CLEAR(q);
4564
4565        return result;
4566}
4567
4568static int is_summary_empty(const struct diff_queue_struct *q)
4569{
4570        int i;
4571
4572        for (i = 0; i < q->nr; i++) {
4573                const struct diff_filepair *p = q->queue[i];
4574
4575                switch (p->status) {
4576                case DIFF_STATUS_DELETED:
4577                case DIFF_STATUS_ADDED:
4578                case DIFF_STATUS_COPIED:
4579                case DIFF_STATUS_RENAMED:
4580                        return 0;
4581                default:
4582                        if (p->score)
4583                                return 0;
4584                        if (p->one->mode && p->two->mode &&
4585                            p->one->mode != p->two->mode)
4586                                return 0;
4587                        break;
4588                }
4589        }
4590        return 1;
4591}
4592
4593static const char rename_limit_warning[] =
4594"inexact rename detection was skipped due to too many files.";
4595
4596static const char degrade_cc_to_c_warning[] =
4597"only found copies from modified paths due to too many files.";
4598
4599static const char rename_limit_advice[] =
4600"you may want to set your %s variable to at least "
4601"%d and retry the command.";
4602
4603void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4604{
4605        if (degraded_cc)
4606                warning(degrade_cc_to_c_warning);
4607        else if (needed)
4608                warning(rename_limit_warning);
4609        else
4610                return;
4611        if (0 < needed && needed < 32767)
4612                warning(rename_limit_advice, varname, needed);
4613}
4614
4615void diff_flush(struct diff_options *options)
4616{
4617        struct diff_queue_struct *q = &diff_queued_diff;
4618        int i, output_format = options->output_format;
4619        int separator = 0;
4620        int dirstat_by_line = 0;
4621
4622        /*
4623         * Order: raw, stat, summary, patch
4624         * or:    name/name-status/checkdiff (other bits clear)
4625         */
4626        if (!q->nr)
4627                goto free_queue;
4628
4629        if (output_format & (DIFF_FORMAT_RAW |
4630                             DIFF_FORMAT_NAME |
4631                             DIFF_FORMAT_NAME_STATUS |
4632                             DIFF_FORMAT_CHECKDIFF)) {
4633                for (i = 0; i < q->nr; i++) {
4634                        struct diff_filepair *p = q->queue[i];
4635                        if (check_pair_status(p))
4636                                flush_one_pair(p, options);
4637                }
4638                separator++;
4639        }
4640
4641        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4642                dirstat_by_line = 1;
4643
4644        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4645            dirstat_by_line) {
4646                struct diffstat_t diffstat;
4647
4648                memset(&diffstat, 0, sizeof(struct diffstat_t));
4649                for (i = 0; i < q->nr; i++) {
4650                        struct diff_filepair *p = q->queue[i];
4651                        if (check_pair_status(p))
4652                                diff_flush_stat(p, options, &diffstat);
4653                }
4654                if (output_format & DIFF_FORMAT_NUMSTAT)
4655                        show_numstat(&diffstat, options);
4656                if (output_format & DIFF_FORMAT_DIFFSTAT)
4657                        show_stats(&diffstat, options);
4658                if (output_format & DIFF_FORMAT_SHORTSTAT)
4659                        show_shortstats(&diffstat, options);
4660                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4661                        show_dirstat_by_line(&diffstat, options);
4662                free_diffstat_info(&diffstat);
4663                separator++;
4664        }
4665        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4666                show_dirstat(options);
4667
4668        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4669                for (i = 0; i < q->nr; i++) {
4670                        diff_summary(options, q->queue[i]);
4671                }
4672                separator++;
4673        }
4674
4675        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4676            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4677            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4678                /*
4679                 * run diff_flush_patch for the exit status. setting
4680                 * options->file to /dev/null should be safe, because we
4681                 * aren't supposed to produce any output anyway.
4682                 */
4683                if (options->close_file)
4684                        fclose(options->file);
4685                options->file = fopen("/dev/null", "w");
4686                if (!options->file)
4687                        die_errno("Could not open /dev/null");
4688                options->close_file = 1;
4689                for (i = 0; i < q->nr; i++) {
4690                        struct diff_filepair *p = q->queue[i];
4691                        if (check_pair_status(p))
4692                                diff_flush_patch(p, options);
4693                        if (options->found_changes)
4694                                break;
4695                }
4696        }
4697
4698        if (output_format & DIFF_FORMAT_PATCH) {
4699                if (separator) {
4700                        fprintf(options->file, "%s%c",
4701                                diff_line_prefix(options),
4702                                options->line_termination);
4703                        if (options->stat_sep) {
4704                                /* attach patch instead of inline */
4705                                fputs(options->stat_sep, options->file);
4706                        }
4707                }
4708
4709                for (i = 0; i < q->nr; i++) {
4710                        struct diff_filepair *p = q->queue[i];
4711                        if (check_pair_status(p))
4712                                diff_flush_patch(p, options);
4713                }
4714        }
4715
4716        if (output_format & DIFF_FORMAT_CALLBACK)
4717                options->format_callback(q, options, options->format_callback_data);
4718
4719        for (i = 0; i < q->nr; i++)
4720                diff_free_filepair(q->queue[i]);
4721free_queue:
4722        free(q->queue);
4723        DIFF_QUEUE_CLEAR(q);
4724        if (options->close_file)
4725                fclose(options->file);
4726
4727        /*
4728         * Report the content-level differences with HAS_CHANGES;
4729         * diff_addremove/diff_change does not set the bit when
4730         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4731         */
4732        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4733                if (options->found_changes)
4734                        DIFF_OPT_SET(options, HAS_CHANGES);
4735                else
4736                        DIFF_OPT_CLR(options, HAS_CHANGES);
4737        }
4738}
4739
4740static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4741{
4742        return (((p->status == DIFF_STATUS_MODIFIED) &&
4743                 ((p->score &&
4744                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4745                  (!p->score &&
4746                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4747                ((p->status != DIFF_STATUS_MODIFIED) &&
4748                 filter_bit_tst(p->status, options)));
4749}
4750
4751static void diffcore_apply_filter(struct diff_options *options)
4752{
4753        int i;
4754        struct diff_queue_struct *q = &diff_queued_diff;
4755        struct diff_queue_struct outq;
4756
4757        DIFF_QUEUE_CLEAR(&outq);
4758
4759        if (!options->filter)
4760                return;
4761
4762        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4763                int found;
4764                for (i = found = 0; !found && i < q->nr; i++) {
4765                        if (match_filter(options, q->queue[i]))
4766                                found++;
4767                }
4768                if (found)
4769                        return;
4770
4771                /* otherwise we will clear the whole queue
4772                 * by copying the empty outq at the end of this
4773                 * function, but first clear the current entries
4774                 * in the queue.
4775                 */
4776                for (i = 0; i < q->nr; i++)
4777                        diff_free_filepair(q->queue[i]);
4778        }
4779        else {
4780                /* Only the matching ones */
4781                for (i = 0; i < q->nr; i++) {
4782                        struct diff_filepair *p = q->queue[i];
4783                        if (match_filter(options, p))
4784                                diff_q(&outq, p);
4785                        else
4786                                diff_free_filepair(p);
4787                }
4788        }
4789        free(q->queue);
4790        *q = outq;
4791}
4792
4793/* Check whether two filespecs with the same mode and size are identical */
4794static int diff_filespec_is_identical(struct diff_filespec *one,
4795                                      struct diff_filespec *two)
4796{
4797        if (S_ISGITLINK(one->mode))
4798                return 0;
4799        if (diff_populate_filespec(one, 0))
4800                return 0;
4801        if (diff_populate_filespec(two, 0))
4802                return 0;
4803        return !memcmp(one->data, two->data, one->size);
4804}
4805
4806static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4807{
4808        if (p->done_skip_stat_unmatch)
4809                return p->skip_stat_unmatch_result;
4810
4811        p->done_skip_stat_unmatch = 1;
4812        p->skip_stat_unmatch_result = 0;
4813        /*
4814         * 1. Entries that come from stat info dirtiness
4815         *    always have both sides (iow, not create/delete),
4816         *    one side of the object name is unknown, with
4817         *    the same mode and size.  Keep the ones that
4818         *    do not match these criteria.  They have real
4819         *    differences.
4820         *
4821         * 2. At this point, the file is known to be modified,
4822         *    with the same mode and size, and the object
4823         *    name of one side is unknown.  Need to inspect
4824         *    the identical contents.
4825         */
4826        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4827            !DIFF_FILE_VALID(p->two) ||
4828            (p->one->oid_valid && p->two->oid_valid) ||
4829            (p->one->mode != p->two->mode) ||
4830            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4831            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4832            (p->one->size != p->two->size) ||
4833            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4834                p->skip_stat_unmatch_result = 1;
4835        return p->skip_stat_unmatch_result;
4836}
4837
4838static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4839{
4840        int i;
4841        struct diff_queue_struct *q = &diff_queued_diff;
4842        struct diff_queue_struct outq;
4843        DIFF_QUEUE_CLEAR(&outq);
4844
4845        for (i = 0; i < q->nr; i++) {
4846                struct diff_filepair *p = q->queue[i];
4847
4848                if (diff_filespec_check_stat_unmatch(p))
4849                        diff_q(&outq, p);
4850                else {
4851                        /*
4852                         * The caller can subtract 1 from skip_stat_unmatch
4853                         * to determine how many paths were dirty only
4854                         * due to stat info mismatch.
4855                         */
4856                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4857                                diffopt->skip_stat_unmatch++;
4858                        diff_free_filepair(p);
4859                }
4860        }
4861        free(q->queue);
4862        *q = outq;
4863}
4864
4865static int diffnamecmp(const void *a_, const void *b_)
4866{
4867        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4868        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4869        const char *name_a, *name_b;
4870
4871        name_a = a->one ? a->one->path : a->two->path;
4872        name_b = b->one ? b->one->path : b->two->path;
4873        return strcmp(name_a, name_b);
4874}
4875
4876void diffcore_fix_diff_index(struct diff_options *options)
4877{
4878        struct diff_queue_struct *q = &diff_queued_diff;
4879        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4880}
4881
4882void diffcore_std(struct diff_options *options)
4883{
4884        /* NOTE please keep the following in sync with diff_tree_combined() */
4885        if (options->skip_stat_unmatch)
4886                diffcore_skip_stat_unmatch(options);
4887        if (!options->found_follow) {
4888                /* See try_to_follow_renames() in tree-diff.c */
4889                if (options->break_opt != -1)
4890                        diffcore_break(options->break_opt);
4891                if (options->detect_rename)
4892                        diffcore_rename(options);
4893                if (options->break_opt != -1)
4894                        diffcore_merge_broken();
4895        }
4896        if (options->pickaxe)
4897                diffcore_pickaxe(options);
4898        if (options->orderfile)
4899                diffcore_order(options->orderfile);
4900        if (!options->found_follow)
4901                /* See try_to_follow_renames() in tree-diff.c */
4902                diff_resolve_rename_copy();
4903        diffcore_apply_filter(options);
4904
4905        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4906                DIFF_OPT_SET(options, HAS_CHANGES);
4907        else
4908                DIFF_OPT_CLR(options, HAS_CHANGES);
4909
4910        options->found_follow = 0;
4911}
4912
4913int diff_result_code(struct diff_options *opt, int status)
4914{
4915        int result = 0;
4916
4917        diff_warn_rename_limit("diff.renameLimit",
4918                               opt->needed_rename_limit,
4919                               opt->degraded_cc_to_c);
4920        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4921            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4922                return status;
4923        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4924            DIFF_OPT_TST(opt, HAS_CHANGES))
4925                result |= 01;
4926        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4927            DIFF_OPT_TST(opt, CHECK_FAILED))
4928                result |= 02;
4929        return result;
4930}
4931
4932int diff_can_quit_early(struct diff_options *opt)
4933{
4934        return (DIFF_OPT_TST(opt, QUICK) &&
4935                !opt->filter &&
4936                DIFF_OPT_TST(opt, HAS_CHANGES));
4937}
4938
4939/*
4940 * Shall changes to this submodule be ignored?
4941 *
4942 * Submodule changes can be configured to be ignored separately for each path,
4943 * but that configuration can be overridden from the command line.
4944 */
4945static int is_submodule_ignored(const char *path, struct diff_options *options)
4946{
4947        int ignored = 0;
4948        unsigned orig_flags = options->flags;
4949        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4950                set_diffopt_flags_from_submodule_config(options, path);
4951        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4952                ignored = 1;
4953        options->flags = orig_flags;
4954        return ignored;
4955}
4956
4957void diff_addremove(struct diff_options *options,
4958                    int addremove, unsigned mode,
4959                    const unsigned char *sha1,
4960                    int sha1_valid,
4961                    const char *concatpath, unsigned dirty_submodule)
4962{
4963        struct diff_filespec *one, *two;
4964
4965        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4966                return;
4967
4968        /* This may look odd, but it is a preparation for
4969         * feeding "there are unchanged files which should
4970         * not produce diffs, but when you are doing copy
4971         * detection you would need them, so here they are"
4972         * entries to the diff-core.  They will be prefixed
4973         * with something like '=' or '*' (I haven't decided
4974         * which but should not make any difference).
4975         * Feeding the same new and old to diff_change()
4976         * also has the same effect.
4977         * Before the final output happens, they are pruned after
4978         * merged into rename/copy pairs as appropriate.
4979         */
4980        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4981                addremove = (addremove == '+' ? '-' :
4982                             addremove == '-' ? '+' : addremove);
4983
4984        if (options->prefix &&
4985            strncmp(concatpath, options->prefix, options->prefix_length))
4986                return;
4987
4988        one = alloc_filespec(concatpath);
4989        two = alloc_filespec(concatpath);
4990
4991        if (addremove != '+')
4992                fill_filespec(one, sha1, sha1_valid, mode);
4993        if (addremove != '-') {
4994                fill_filespec(two, sha1, sha1_valid, mode);
4995                two->dirty_submodule = dirty_submodule;
4996        }
4997
4998        diff_queue(&diff_queued_diff, one, two);
4999        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5000                DIFF_OPT_SET(options, HAS_CHANGES);
5001}
5002
5003void diff_change(struct diff_options *options,
5004                 unsigned old_mode, unsigned new_mode,
5005                 const unsigned char *old_sha1,
5006                 const unsigned char *new_sha1,
5007                 int old_sha1_valid, int new_sha1_valid,
5008                 const char *concatpath,
5009                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5010{
5011        struct diff_filespec *one, *two;
5012        struct diff_filepair *p;
5013
5014        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5015            is_submodule_ignored(concatpath, options))
5016                return;
5017
5018        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5019                unsigned tmp;
5020                const unsigned char *tmp_c;
5021                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
5022                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
5023                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
5024                        new_sha1_valid = tmp;
5025                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
5026                        new_dirty_submodule = tmp;
5027        }
5028
5029        if (options->prefix &&
5030            strncmp(concatpath, options->prefix, options->prefix_length))
5031                return;
5032
5033        one = alloc_filespec(concatpath);
5034        two = alloc_filespec(concatpath);
5035        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5036        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5037        one->dirty_submodule = old_dirty_submodule;
5038        two->dirty_submodule = new_dirty_submodule;
5039        p = diff_queue(&diff_queued_diff, one, two);
5040
5041        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5042                return;
5043
5044        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5045            !diff_filespec_check_stat_unmatch(p))
5046                return;
5047
5048        DIFF_OPT_SET(options, HAS_CHANGES);
5049}
5050
5051struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5052{
5053        struct diff_filepair *pair;
5054        struct diff_filespec *one, *two;
5055
5056        if (options->prefix &&
5057            strncmp(path, options->prefix, options->prefix_length))
5058                return NULL;
5059
5060        one = alloc_filespec(path);
5061        two = alloc_filespec(path);
5062        pair = diff_queue(&diff_queued_diff, one, two);
5063        pair->is_unmerged = 1;
5064        return pair;
5065}
5066
5067static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5068                size_t *outsize)
5069{
5070        struct diff_tempfile *temp;
5071        const char *argv[3];
5072        const char **arg = argv;
5073        struct child_process child = CHILD_PROCESS_INIT;
5074        struct strbuf buf = STRBUF_INIT;
5075        int err = 0;
5076
5077        temp = prepare_temp_file(spec->path, spec);
5078        *arg++ = pgm;
5079        *arg++ = temp->name;
5080        *arg = NULL;
5081
5082        child.use_shell = 1;
5083        child.argv = argv;
5084        child.out = -1;
5085        if (start_command(&child)) {
5086                remove_tempfile();
5087                return NULL;
5088        }
5089
5090        if (strbuf_read(&buf, child.out, 0) < 0)
5091                err = error("error reading from textconv command '%s'", pgm);
5092        close(child.out);
5093
5094        if (finish_command(&child) || err) {
5095                strbuf_release(&buf);
5096                remove_tempfile();
5097                return NULL;
5098        }
5099        remove_tempfile();
5100
5101        return strbuf_detach(&buf, outsize);
5102}
5103
5104size_t fill_textconv(struct userdiff_driver *driver,
5105                     struct diff_filespec *df,
5106                     char **outbuf)
5107{
5108        size_t size;
5109
5110        if (!driver) {
5111                if (!DIFF_FILE_VALID(df)) {
5112                        *outbuf = "";
5113                        return 0;
5114                }
5115                if (diff_populate_filespec(df, 0))
5116                        die("unable to read files to diff");
5117                *outbuf = df->data;
5118                return df->size;
5119        }
5120
5121        if (!driver->textconv)
5122                die("BUG: fill_textconv called with non-textconv driver");
5123
5124        if (driver->textconv_cache && df->oid_valid) {
5125                *outbuf = notes_cache_get(driver->textconv_cache,
5126                                          df->oid.hash,
5127                                          &size);
5128                if (*outbuf)
5129                        return size;
5130        }
5131
5132        *outbuf = run_textconv(driver->textconv, df, &size);
5133        if (!*outbuf)
5134                die("unable to read files to diff");
5135
5136        if (driver->textconv_cache && df->oid_valid) {
5137                /* ignore errors, as we might be in a readonly repository */
5138                notes_cache_put(driver->textconv_cache, df->oid.hash, *outbuf,
5139                                size);
5140                /*
5141                 * we could save up changes and flush them all at the end,
5142                 * but we would need an extra call after all diffing is done.
5143                 * Since generating a cache entry is the slow path anyway,
5144                 * this extra overhead probably isn't a big deal.
5145                 */
5146                notes_cache_write(driver->textconv_cache);
5147        }
5148
5149        return size;
5150}
5151
5152void setup_diff_pager(struct diff_options *opt)
5153{
5154        /*
5155         * If the user asked for our exit code, then either they want --quiet
5156         * or --exit-code. We should definitely not bother with a pager in the
5157         * former case, as we will generate no output. Since we still properly
5158         * report our exit code even when a pager is run, we _could_ run a
5159         * pager with --exit-code. But since we have not done so historically,
5160         * and because it is easy to find people oneline advising "git diff
5161         * --exit-code" in hooks and other scripts, we do not do so.
5162         */
5163        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5164            check_pager_config("diff") != 0)
5165                setup_pager();
5166}