diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14 #include "userdiff.h"
  15 #include "sigchain.h"
  16 #include "submodule.h"
  17 #include "ll-merge.h"
  18 #include "string-list.h"
  19
  20 #ifdef NO_FAST_WORKING_DIRECTORY
  21 #define FAST_WORKING_DIRECTORY 0
  22 #else
  23 #define FAST_WORKING_DIRECTORY 1
  24 #endif
  25
  26 static int diff_detect_rename_default;
  27 static int diff_rename_limit_default = 400;
  28 static int diff_suppress_blank_empty;
  29 static int diff_use_color_default = -1;
  30 static int diff_context_default = 3;
  31 static const char *diff_word_regex_cfg;
  32 static const char *external_diff_cmd_cfg;
  33 int diff_auto_refresh_index = 1;
  34 static int diff_mnemonic_prefix;
  35 static int diff_no_prefix;
  36 static int diff_stat_graph_width;
  37 static int diff_dirstat_permille_default = 30;
  38 static struct diff_options default_diff_options;
  39 static long diff_algorithm;
  40
  41 static char diff_colors[][COLOR_MAXLEN] = {
  42         GIT_COLOR_RESET,
  43         GIT_COLOR_NORMAL,       /* PLAIN */
  44         GIT_COLOR_BOLD,         /* METAINFO */
  45         GIT_COLOR_CYAN,         /* FRAGINFO */
  46         GIT_COLOR_RED,          /* OLD */
  47         GIT_COLOR_GREEN,        /* NEW */
  48         GIT_COLOR_YELLOW,       /* COMMIT */
  49         GIT_COLOR_BG_RED,       /* WHITESPACE */
  50         GIT_COLOR_NORMAL,       /* FUNCINFO */
  51 };
  52
  53 static int parse_diff_color_slot(const char *var, int ofs)
  54 {
  55         if (!strcasecmp(var+ofs, "plain"))
  56                 return DIFF_PLAIN;
  57         if (!strcasecmp(var+ofs, "meta"))
  58                 return DIFF_METAINFO;
  59         if (!strcasecmp(var+ofs, "frag"))
  60                 return DIFF_FRAGINFO;
  61         if (!strcasecmp(var+ofs, "old"))
  62                 return DIFF_FILE_OLD;
  63         if (!strcasecmp(var+ofs, "new"))
  64                 return DIFF_FILE_NEW;
  65         if (!strcasecmp(var+ofs, "commit"))
  66                 return DIFF_COMMIT;
  67         if (!strcasecmp(var+ofs, "whitespace"))
  68                 return DIFF_WHITESPACE;
  69         if (!strcasecmp(var+ofs, "func"))
  70                 return DIFF_FUNCINFO;
  71         return -1;
  72 }
  73
  74 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  75                                 struct strbuf *errmsg)
  76 {
  77         char *params_copy = xstrdup(params_string);
  78         struct string_list params = STRING_LIST_INIT_NODUP;
  79         int ret = 0;
  80         int i;
  81
  82         if (*params_copy)
  83                 string_list_split_in_place(&params, params_copy, ',', -1);
  84         for (i = 0; i < params.nr; i++) {
  85                 const char *p = params.items[i].string;
  86                 if (!strcmp(p, "changes")) {
  87                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  88                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  89                 } else if (!strcmp(p, "lines")) {
  90                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  91                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  92                 } else if (!strcmp(p, "files")) {
  93                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  94                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  95                 } else if (!strcmp(p, "noncumulative")) {
  96                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  97                 } else if (!strcmp(p, "cumulative")) {
  98                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  99                 } else if (isdigit(*p)) {
 100                         char *end;
 101                         int permille = strtoul(p, &end, 10) * 10;
 102                         if (*end == '.' && isdigit(*++end)) {
 103                                 /* only use first digit */
 104                                 permille += *end - '0';
 105                                 /* .. and ignore any further digits */
 106                                 while (isdigit(*++end))
 107                                         ; /* nothing */
 108                         }
 109                         if (!*end)
 110                                 options->dirstat_permille = permille;
 111                         else {
 112                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 113                                             p);
 114                                 ret++;
 115                         }
 116                 } else {
 117                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 118                         ret++;
 119                 }
 120
 121         }
 122         string_list_clear(&params, 0);
 123         free(params_copy);
 124         return ret;
 125 }
 126
 127 static int parse_submodule_params(struct diff_options *options, const char *value)
 128 {
 129         if (!strcmp(value, "log"))
 130                 DIFF_OPT_SET(options, SUBMODULE_LOG);
 131         else if (!strcmp(value, "short"))
 132                 DIFF_OPT_CLR(options, SUBMODULE_LOG);
 133         else
 134                 return -1;
 135         return 0;
 136 }
 137
 138 static int git_config_rename(const char *var, const char *value)
 139 {
 140         if (!value)
 141                 return DIFF_DETECT_RENAME;
 142         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 143                 return  DIFF_DETECT_COPY;
 144         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 145 }
 146
 147 long parse_algorithm_value(const char *value)
 148 {
 149         if (!value)
 150                 return -1;
 151         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 152                 return 0;
 153         else if (!strcasecmp(value, "minimal"))
 154                 return XDF_NEED_MINIMAL;
 155         else if (!strcasecmp(value, "patience"))
 156                 return XDF_PATIENCE_DIFF;
 157         else if (!strcasecmp(value, "histogram"))
 158                 return XDF_HISTOGRAM_DIFF;
 159         return -1;
 160 }
 161
 162 /*
 163  * These are to give UI layer defaults.
 164  * The core-level commands such as git-diff-files should
 165  * never be affected by the setting of diff.renames
 166  * the user happens to have in the configuration file.
 167  */
 168 int git_diff_ui_config(const char *var, const char *value, void *cb)
 169 {
 170         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 171                 diff_use_color_default = git_config_colorbool(var, value);
 172                 return 0;
 173         }
 174         if (!strcmp(var, "diff.context")) {
 175                 diff_context_default = git_config_int(var, value);
 176                 if (diff_context_default < 0)
 177                         return -1;
 178                 return 0;
 179         }
 180         if (!strcmp(var, "diff.renames")) {
 181                 diff_detect_rename_default = git_config_rename(var, value);
 182                 return 0;
 183         }
 184         if (!strcmp(var, "diff.autorefreshindex")) {
 185                 diff_auto_refresh_index = git_config_bool(var, value);
 186                 return 0;
 187         }
 188         if (!strcmp(var, "diff.mnemonicprefix")) {
 189                 diff_mnemonic_prefix = git_config_bool(var, value);
 190                 return 0;
 191         }
 192         if (!strcmp(var, "diff.noprefix")) {
 193                 diff_no_prefix = git_config_bool(var, value);
 194                 return 0;
 195         }
 196         if (!strcmp(var, "diff.statgraphwidth")) {
 197                 diff_stat_graph_width = git_config_int(var, value);
 198                 return 0;
 199         }
 200         if (!strcmp(var, "diff.external"))
 201                 return git_config_string(&external_diff_cmd_cfg, var, value);
 202         if (!strcmp(var, "diff.wordregex"))
 203                 return git_config_string(&diff_word_regex_cfg, var, value);
 204
 205         if (!strcmp(var, "diff.ignoresubmodules"))
 206                 handle_ignore_submodules_arg(&default_diff_options, value);
 207
 208         if (!strcmp(var, "diff.submodule")) {
 209                 if (parse_submodule_params(&default_diff_options, value))
 210                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 211                                 value);
 212                 return 0;
 213         }
 214
 215         if (!strcmp(var, "diff.algorithm")) {
 216                 diff_algorithm = parse_algorithm_value(value);
 217                 if (diff_algorithm < 0)
 218                         return -1;
 219                 return 0;
 220         }
 221
 222         if (git_color_config(var, value, cb) < 0)
 223                 return -1;
 224
 225         return git_diff_basic_config(var, value, cb);
 226 }
 227
 228 int git_diff_basic_config(const char *var, const char *value, void *cb)
 229 {
 230         if (!strcmp(var, "diff.renamelimit")) {
 231                 diff_rename_limit_default = git_config_int(var, value);
 232                 return 0;
 233         }
 234
 235         if (userdiff_config(var, value) < 0)
 236                 return -1;
 237
 238         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 239                 int slot = parse_diff_color_slot(var, 11);
 240                 if (slot < 0)
 241                         return 0;
 242                 if (!value)
 243                         return config_error_nonbool(var);
 244                 color_parse(value, var, diff_colors[slot]);
 245                 return 0;
 246         }
 247
 248         /* like GNU diff's --suppress-blank-empty option  */
 249         if (!strcmp(var, "diff.suppressblankempty") ||
 250                         /* for backwards compatibility */
 251                         !strcmp(var, "diff.suppress-blank-empty")) {
 252                 diff_suppress_blank_empty = git_config_bool(var, value);
 253                 return 0;
 254         }
 255
 256         if (!strcmp(var, "diff.dirstat")) {
 257                 struct strbuf errmsg = STRBUF_INIT;
 258                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 259                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 260                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 261                                 errmsg.buf);
 262                 strbuf_release(&errmsg);
 263                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 264                 return 0;
 265         }
 266
 267         if (!prefixcmp(var, "submodule."))
 268                 return parse_submodule_config_option(var, value);
 269
 270         return git_default_config(var, value, cb);
 271 }
 272
 273 static char *quote_two(const char *one, const char *two)
 274 {
 275         int need_one = quote_c_style(one, NULL, NULL, 1);
 276         int need_two = quote_c_style(two, NULL, NULL, 1);
 277         struct strbuf res = STRBUF_INIT;
 278
 279         if (need_one + need_two) {
 280                 strbuf_addch(&res, '"');
 281                 quote_c_style(one, &res, NULL, 1);
 282                 quote_c_style(two, &res, NULL, 1);
 283                 strbuf_addch(&res, '"');
 284         } else {
 285                 strbuf_addstr(&res, one);
 286                 strbuf_addstr(&res, two);
 287         }
 288         return strbuf_detach(&res, NULL);
 289 }
 290
 291 static const char *external_diff(void)
 292 {
 293         static const char *external_diff_cmd = NULL;
 294         static int done_preparing = 0;
 295
 296         if (done_preparing)
 297                 return external_diff_cmd;
 298         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 299         if (!external_diff_cmd)
 300                 external_diff_cmd = external_diff_cmd_cfg;
 301         done_preparing = 1;
 302         return external_diff_cmd;
 303 }
 304
 305 static struct diff_tempfile {
 306         const char *name; /* filename external diff should read from */
 307         char hex[41];
 308         char mode[10];
 309         char tmp_path[PATH_MAX];
 310 } diff_temp[2];
 311
 312 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 313
 314 struct emit_callback {
 315         int color_diff;
 316         unsigned ws_rule;
 317         int blank_at_eof_in_preimage;
 318         int blank_at_eof_in_postimage;
 319         int lno_in_preimage;
 320         int lno_in_postimage;
 321         sane_truncate_fn truncate;
 322         const char **label_path;
 323         struct diff_words_data *diff_words;
 324         struct diff_options *opt;
 325         int *found_changesp;
 326         struct strbuf *header;
 327 };
 328
 329 static int count_lines(const char *data, int size)
 330 {
 331         int count, ch, completely_empty = 1, nl_just_seen = 0;
 332         count = 0;
 333         while (0 < size--) {
 334                 ch = *data++;
 335                 if (ch == '\n') {
 336                         count++;
 337                         nl_just_seen = 1;
 338                         completely_empty = 0;
 339                 }
 340                 else {
 341                         nl_just_seen = 0;
 342                         completely_empty = 0;
 343                 }
 344         }
 345         if (completely_empty)
 346                 return 0;
 347         if (!nl_just_seen)
 348                 count++; /* no trailing newline */
 349         return count;
 350 }
 351
 352 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 353 {
 354         if (!DIFF_FILE_VALID(one)) {
 355                 mf->ptr = (char *)""; /* does not matter */
 356                 mf->size = 0;
 357                 return 0;
 358         }
 359         else if (diff_populate_filespec(one, 0))
 360                 return -1;
 361
 362         mf->ptr = one->data;
 363         mf->size = one->size;
 364         return 0;
 365 }
 366
 367 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 368 static unsigned long diff_filespec_size(struct diff_filespec *one)
 369 {
 370         if (!DIFF_FILE_VALID(one))
 371                 return 0;
 372         diff_populate_filespec(one, 1);
 373         return one->size;
 374 }
 375
 376 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 377 {
 378         char *ptr = mf->ptr;
 379         long size = mf->size;
 380         int cnt = 0;
 381
 382         if (!size)
 383                 return cnt;
 384         ptr += size - 1; /* pointing at the very end */
 385         if (*ptr != '\n')
 386                 ; /* incomplete line */
 387         else
 388                 ptr--; /* skip the last LF */
 389         while (mf->ptr < ptr) {
 390                 char *prev_eol;
 391                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 392                         if (*prev_eol == '\n')
 393                                 break;
 394                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 395                         break;
 396                 cnt++;
 397                 ptr = prev_eol - 1;
 398         }
 399         return cnt;
 400 }
 401
 402 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 403                                struct emit_callback *ecbdata)
 404 {
 405         int l1, l2, at;
 406         unsigned ws_rule = ecbdata->ws_rule;
 407         l1 = count_trailing_blank(mf1, ws_rule);
 408         l2 = count_trailing_blank(mf2, ws_rule);
 409         if (l2 <= l1) {
 410                 ecbdata->blank_at_eof_in_preimage = 0;
 411                 ecbdata->blank_at_eof_in_postimage = 0;
 412                 return;
 413         }
 414         at = count_lines(mf1->ptr, mf1->size);
 415         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 416
 417         at = count_lines(mf2->ptr, mf2->size);
 418         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 419 }
 420
 421 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 422                         int first, const char *line, int len)
 423 {
 424         int has_trailing_newline, has_trailing_carriage_return;
 425         int nofirst;
 426         FILE *file = o->file;
 427
 428         fputs(diff_line_prefix(o), file);
 429
 430         if (len == 0) {
 431                 has_trailing_newline = (first == '\n');
 432                 has_trailing_carriage_return = (!has_trailing_newline &&
 433                                                 (first == '\r'));
 434                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 435         } else {
 436                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 437                 if (has_trailing_newline)
 438                         len--;
 439                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 440                 if (has_trailing_carriage_return)
 441                         len--;
 442                 nofirst = 0;
 443         }
 444
 445         if (len || !nofirst) {
 446                 fputs(set, file);
 447                 if (!nofirst)
 448                         fputc(first, file);
 449                 fwrite(line, len, 1, file);
 450                 fputs(reset, file);
 451         }
 452         if (has_trailing_carriage_return)
 453                 fputc('\r', file);
 454         if (has_trailing_newline)
 455                 fputc('\n', file);
 456 }
 457
 458 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 459                       const char *line, int len)
 460 {
 461         emit_line_0(o, set, reset, line[0], line+1, len-1);
 462 }
 463
 464 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 465 {
 466         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 467               ecbdata->blank_at_eof_in_preimage &&
 468               ecbdata->blank_at_eof_in_postimage &&
 469               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 470               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 471                 return 0;
 472         return ws_blank_line(line, len, ecbdata->ws_rule);
 473 }
 474
 475 static void emit_add_line(const char *reset,
 476                           struct emit_callback *ecbdata,
 477                           const char *line, int len)
 478 {
 479         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 480         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 481
 482         if (!*ws)
 483                 emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 484         else if (new_blank_line_at_eof(ecbdata, line, len))
 485                 /* Blank line at EOF - paint '+' as well */
 486                 emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 487         else {
 488                 /* Emit just the prefix, then the rest. */
 489                 emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 490                 ws_check_emit(line, len, ecbdata->ws_rule,
 491                               ecbdata->opt->file, set, reset, ws);
 492         }
 493 }
 494
 495 static void emit_hunk_header(struct emit_callback *ecbdata,
 496                              const char *line, int len)
 497 {
 498         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 499         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 500         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 501         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 502         static const char atat[2] = { '@', '@' };
 503         const char *cp, *ep;
 504         struct strbuf msgbuf = STRBUF_INIT;
 505         int org_len = len;
 506         int i = 1;
 507
 508         /*
 509          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 510          * it always is at least 10 bytes long.
 511          */
 512         if (len < 10 ||
 513             memcmp(line, atat, 2) ||
 514             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 515                 emit_line(ecbdata->opt, plain, reset, line, len);
 516                 return;
 517         }
 518         ep += 2; /* skip over @@ */
 519
 520         /* The hunk header in fraginfo color */
 521         strbuf_add(&msgbuf, frag, strlen(frag));
 522         strbuf_add(&msgbuf, line, ep - line);
 523         strbuf_add(&msgbuf, reset, strlen(reset));
 524
 525         /*
 526          * trailing "\r\n"
 527          */
 528         for ( ; i < 3; i++)
 529                 if (line[len - i] == '\r' || line[len - i] == '\n')
 530                         len--;
 531
 532         /* blank before the func header */
 533         for (cp = ep; ep - line < len; ep++)
 534                 if (*ep != ' ' && *ep != '\t')
 535                         break;
 536         if (ep != cp) {
 537                 strbuf_add(&msgbuf, plain, strlen(plain));
 538                 strbuf_add(&msgbuf, cp, ep - cp);
 539                 strbuf_add(&msgbuf, reset, strlen(reset));
 540         }
 541
 542         if (ep < line + len) {
 543                 strbuf_add(&msgbuf, func, strlen(func));
 544                 strbuf_add(&msgbuf, ep, line + len - ep);
 545                 strbuf_add(&msgbuf, reset, strlen(reset));
 546         }
 547
 548         strbuf_add(&msgbuf, line + len, org_len - len);
 549         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 550         strbuf_release(&msgbuf);
 551 }
 552
 553 static struct diff_tempfile *claim_diff_tempfile(void) {
 554         int i;
 555         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 556                 if (!diff_temp[i].name)
 557                         return diff_temp + i;
 558         die("BUG: diff is failing to clean up its tempfiles");
 559 }
 560
 561 static int remove_tempfile_installed;
 562
 563 static void remove_tempfile(void)
 564 {
 565         int i;
 566         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 567                 if (diff_temp[i].name == diff_temp[i].tmp_path)
 568                         unlink_or_warn(diff_temp[i].name);
 569                 diff_temp[i].name = NULL;
 570         }
 571 }
 572
 573 static void remove_tempfile_on_signal(int signo)
 574 {
 575         remove_tempfile();
 576         sigchain_pop(signo);
 577         raise(signo);
 578 }
 579
 580 static void print_line_count(FILE *file, int count)
 581 {
 582         switch (count) {
 583         case 0:
 584                 fprintf(file, "0,0");
 585                 break;
 586         case 1:
 587                 fprintf(file, "1");
 588                 break;
 589         default:
 590                 fprintf(file, "1,%d", count);
 591                 break;
 592         }
 593 }
 594
 595 static void emit_rewrite_lines(struct emit_callback *ecb,
 596                                int prefix, const char *data, int size)
 597 {
 598         const char *endp = NULL;
 599         static const char *nneof = " No newline at end of file\n";
 600         const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 601         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 602
 603         while (0 < size) {
 604                 int len;
 605
 606                 endp = memchr(data, '\n', size);
 607                 len = endp ? (endp - data + 1) : size;
 608                 if (prefix != '+') {
 609                         ecb->lno_in_preimage++;
 610                         emit_line_0(ecb->opt, old, reset, '-',
 611                                     data, len);
 612                 } else {
 613                         ecb->lno_in_postimage++;
 614                         emit_add_line(reset, ecb, data, len);
 615                 }
 616                 size -= len;
 617                 data += len;
 618         }
 619         if (!endp) {
 620                 const char *plain = diff_get_color(ecb->color_diff,
 621                                                    DIFF_PLAIN);
 622                 putc('\n', ecb->opt->file);
 623                 emit_line_0(ecb->opt, plain, reset, '\\',
 624                             nneof, strlen(nneof));
 625         }
 626 }
 627
 628 static void emit_rewrite_diff(const char *name_a,
 629                               const char *name_b,
 630                               struct diff_filespec *one,
 631                               struct diff_filespec *two,
 632                               struct userdiff_driver *textconv_one,
 633                               struct userdiff_driver *textconv_two,
 634                               struct diff_options *o)
 635 {
 636         int lc_a, lc_b;
 637         const char *name_a_tab, *name_b_tab;
 638         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 639         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 640         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 641         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 642         const char *a_prefix, *b_prefix;
 643         char *data_one, *data_two;
 644         size_t size_one, size_two;
 645         struct emit_callback ecbdata;
 646         const char *line_prefix = diff_line_prefix(o);
 647
 648         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 649                 a_prefix = o->b_prefix;
 650                 b_prefix = o->a_prefix;
 651         } else {
 652                 a_prefix = o->a_prefix;
 653                 b_prefix = o->b_prefix;
 654         }
 655
 656         name_a += (*name_a == '/');
 657         name_b += (*name_b == '/');
 658         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 659         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 660
 661         strbuf_reset(&a_name);
 662         strbuf_reset(&b_name);
 663         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 664         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 665
 666         size_one = fill_textconv(textconv_one, one, &data_one);
 667         size_two = fill_textconv(textconv_two, two, &data_two);
 668
 669         memset(&ecbdata, 0, sizeof(ecbdata));
 670         ecbdata.color_diff = want_color(o->use_color);
 671         ecbdata.found_changesp = &o->found_changes;
 672         ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 673         ecbdata.opt = o;
 674         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 675                 mmfile_t mf1, mf2;
 676                 mf1.ptr = (char *)data_one;
 677                 mf2.ptr = (char *)data_two;
 678                 mf1.size = size_one;
 679                 mf2.size = size_two;
 680                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 681         }
 682         ecbdata.lno_in_preimage = 1;
 683         ecbdata.lno_in_postimage = 1;
 684
 685         lc_a = count_lines(data_one, size_one);
 686         lc_b = count_lines(data_two, size_two);
 687         fprintf(o->file,
 688                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 689                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 690                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 691                 line_prefix, fraginfo);
 692         if (!o->irreversible_delete)
 693                 print_line_count(o->file, lc_a);
 694         else
 695                 fprintf(o->file, "?,?");
 696         fprintf(o->file, " +");
 697         print_line_count(o->file, lc_b);
 698         fprintf(o->file, " @@%s\n", reset);
 699         if (lc_a && !o->irreversible_delete)
 700                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 701         if (lc_b)
 702                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 703         if (textconv_one)
 704                 free((char *)data_one);
 705         if (textconv_two)
 706                 free((char *)data_two);
 707 }
 708
 709 struct diff_words_buffer {
 710         mmfile_t text;
 711         long alloc;
 712         struct diff_words_orig {
 713                 const char *begin, *end;
 714         } *orig;
 715         int orig_nr, orig_alloc;
 716 };
 717
 718 static void diff_words_append(char *line, unsigned long len,
 719                 struct diff_words_buffer *buffer)
 720 {
 721         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 722         line++;
 723         len--;
 724         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 725         buffer->text.size += len;
 726         buffer->text.ptr[buffer->text.size] = '\0';
 727 }
 728
 729 struct diff_words_style_elem {
 730         const char *prefix;
 731         const char *suffix;
 732         const char *color; /* NULL; filled in by the setup code if
 733                             * color is enabled */
 734 };
 735
 736 struct diff_words_style {
 737         enum diff_words_type type;
 738         struct diff_words_style_elem new, old, ctx;
 739         const char *newline;
 740 };
 741
 742 static struct diff_words_style diff_words_styles[] = {
 743         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 744         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 745         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 746 };
 747
 748 struct diff_words_data {
 749         struct diff_words_buffer minus, plus;
 750         const char *current_plus;
 751         int last_minus;
 752         struct diff_options *opt;
 753         regex_t *word_regex;
 754         enum diff_words_type type;
 755         struct diff_words_style *style;
 756 };
 757
 758 static int fn_out_diff_words_write_helper(FILE *fp,
 759                                           struct diff_words_style_elem *st_el,
 760                                           const char *newline,
 761                                           size_t count, const char *buf,
 762                                           const char *line_prefix)
 763 {
 764         int print = 0;
 765
 766         while (count) {
 767                 char *p = memchr(buf, '\n', count);
 768                 if (print)
 769                         fputs(line_prefix, fp);
 770                 if (p != buf) {
 771                         if (st_el->color && fputs(st_el->color, fp) < 0)
 772                                 return -1;
 773                         if (fputs(st_el->prefix, fp) < 0 ||
 774                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 775                             fputs(st_el->suffix, fp) < 0)
 776                                 return -1;
 777                         if (st_el->color && *st_el->color
 778                             && fputs(GIT_COLOR_RESET, fp) < 0)
 779                                 return -1;
 780                 }
 781                 if (!p)
 782                         return 0;
 783                 if (fputs(newline, fp) < 0)
 784                         return -1;
 785                 count -= p + 1 - buf;
 786                 buf = p + 1;
 787                 print = 1;
 788         }
 789         return 0;
 790 }
 791
 792 /*
 793  * '--color-words' algorithm can be described as:
 794  *
 795  *   1. collect a the minus/plus lines of a diff hunk, divided into
 796  *      minus-lines and plus-lines;
 797  *
 798  *   2. break both minus-lines and plus-lines into words and
 799  *      place them into two mmfile_t with one word for each line;
 800  *
 801  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 802  *
 803  * And for the common parts of the both file, we output the plus side text.
 804  * diff_words->current_plus is used to trace the current position of the plus file
 805  * which printed. diff_words->last_minus is used to trace the last minus word
 806  * printed.
 807  *
 808  * For '--graph' to work with '--color-words', we need to output the graph prefix
 809  * on each line of color words output. Generally, there are two conditions on
 810  * which we should output the prefix.
 811  *
 812  *   1. diff_words->last_minus == 0 &&
 813  *      diff_words->current_plus == diff_words->plus.text.ptr
 814  *
 815  *      that is: the plus text must start as a new line, and if there is no minus
 816  *      word printed, a graph prefix must be printed.
 817  *
 818  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 819  *      *(diff_words->current_plus - 1) == '\n'
 820  *
 821  *      that is: a graph prefix must be printed following a '\n'
 822  */
 823 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 824 {
 825         if ((diff_words->last_minus == 0 &&
 826                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 827                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 828                 *(diff_words->current_plus - 1) == '\n')) {
 829                 return 1;
 830         } else {
 831                 return 0;
 832         }
 833 }
 834
 835 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 836 {
 837         struct diff_words_data *diff_words = priv;
 838         struct diff_words_style *style = diff_words->style;
 839         int minus_first, minus_len, plus_first, plus_len;
 840         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 841         struct diff_options *opt = diff_words->opt;
 842         const char *line_prefix;
 843
 844         if (line[0] != '@' || parse_hunk_header(line, len,
 845                         &minus_first, &minus_len, &plus_first, &plus_len))
 846                 return;
 847
 848         assert(opt);
 849         line_prefix = diff_line_prefix(opt);
 850
 851         /* POSIX requires that first be decremented by one if len == 0... */
 852         if (minus_len) {
 853                 minus_begin = diff_words->minus.orig[minus_first].begin;
 854                 minus_end =
 855                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 856         } else
 857                 minus_begin = minus_end =
 858                         diff_words->minus.orig[minus_first].end;
 859
 860         if (plus_len) {
 861                 plus_begin = diff_words->plus.orig[plus_first].begin;
 862                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 863         } else
 864                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 865
 866         if (color_words_output_graph_prefix(diff_words)) {
 867                 fputs(line_prefix, diff_words->opt->file);
 868         }
 869         if (diff_words->current_plus != plus_begin) {
 870                 fn_out_diff_words_write_helper(diff_words->opt->file,
 871                                 &style->ctx, style->newline,
 872                                 plus_begin - diff_words->current_plus,
 873                                 diff_words->current_plus, line_prefix);
 874                 if (*(plus_begin - 1) == '\n')
 875                         fputs(line_prefix, diff_words->opt->file);
 876         }
 877         if (minus_begin != minus_end) {
 878                 fn_out_diff_words_write_helper(diff_words->opt->file,
 879                                 &style->old, style->newline,
 880                                 minus_end - minus_begin, minus_begin,
 881                                 line_prefix);
 882         }
 883         if (plus_begin != plus_end) {
 884                 fn_out_diff_words_write_helper(diff_words->opt->file,
 885                                 &style->new, style->newline,
 886                                 plus_end - plus_begin, plus_begin,
 887                                 line_prefix);
 888         }
 889
 890         diff_words->current_plus = plus_end;
 891         diff_words->last_minus = minus_first;
 892 }
 893
 894 /* This function starts looking at *begin, and returns 0 iff a word was found. */
 895 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 896                 int *begin, int *end)
 897 {
 898         if (word_regex && *begin < buffer->size) {
 899                 regmatch_t match[1];
 900                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 901                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 902                                         '\n', match[0].rm_eo - match[0].rm_so);
 903                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 904                         *begin += match[0].rm_so;
 905                         return *begin >= *end;
 906                 }
 907                 return -1;
 908         }
 909
 910         /* find the next word */
 911         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 912                 (*begin)++;
 913         if (*begin >= buffer->size)
 914                 return -1;
 915
 916         /* find the end of the word */
 917         *end = *begin + 1;
 918         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 919                 (*end)++;
 920
 921         return 0;
 922 }
 923
 924 /*
 925  * This function splits the words in buffer->text, stores the list with
 926  * newline separator into out, and saves the offsets of the original words
 927  * in buffer->orig.
 928  */
 929 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 930                 regex_t *word_regex)
 931 {
 932         int i, j;
 933         long alloc = 0;
 934
 935         out->size = 0;
 936         out->ptr = NULL;
 937
 938         /* fake an empty "0th" word */
 939         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 940         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 941         buffer->orig_nr = 1;
 942
 943         for (i = 0; i < buffer->text.size; i++) {
 944                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 945                         return;
 946
 947                 /* store original boundaries */
 948                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 949                                 buffer->orig_alloc);
 950                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 951                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 952                 buffer->orig_nr++;
 953
 954                 /* store one word */
 955                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 956                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 957                 out->ptr[out->size + j - i] = '\n';
 958                 out->size += j - i + 1;
 959
 960                 i = j - 1;
 961         }
 962 }
 963
 964 /* this executes the word diff on the accumulated buffers */
 965 static void diff_words_show(struct diff_words_data *diff_words)
 966 {
 967         xpparam_t xpp;
 968         xdemitconf_t xecfg;
 969         mmfile_t minus, plus;
 970         struct diff_words_style *style = diff_words->style;
 971
 972         struct diff_options *opt = diff_words->opt;
 973         const char *line_prefix;
 974
 975         assert(opt);
 976         line_prefix = diff_line_prefix(opt);
 977
 978         /* special case: only removal */
 979         if (!diff_words->plus.text.size) {
 980                 fputs(line_prefix, diff_words->opt->file);
 981                 fn_out_diff_words_write_helper(diff_words->opt->file,
 982                         &style->old, style->newline,
 983                         diff_words->minus.text.size,
 984                         diff_words->minus.text.ptr, line_prefix);
 985                 diff_words->minus.text.size = 0;
 986                 return;
 987         }
 988
 989         diff_words->current_plus = diff_words->plus.text.ptr;
 990         diff_words->last_minus = 0;
 991
 992         memset(&xpp, 0, sizeof(xpp));
 993         memset(&xecfg, 0, sizeof(xecfg));
 994         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 995         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 996         xpp.flags = 0;
 997         /* as only the hunk header will be parsed, we need a 0-context */
 998         xecfg.ctxlen = 0;
 999         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1000                       &xpp, &xecfg);
1001         free(minus.ptr);
1002         free(plus.ptr);
1003         if (diff_words->current_plus != diff_words->plus.text.ptr +
1004                         diff_words->plus.text.size) {
1005                 if (color_words_output_graph_prefix(diff_words))
1006                         fputs(line_prefix, diff_words->opt->file);
1007                 fn_out_diff_words_write_helper(diff_words->opt->file,
1008                         &style->ctx, style->newline,
1009                         diff_words->plus.text.ptr + diff_words->plus.text.size
1010                         - diff_words->current_plus, diff_words->current_plus,
1011                         line_prefix);
1012         }
1013         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1014 }
1015
1016 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1017 static void diff_words_flush(struct emit_callback *ecbdata)
1018 {
1019         if (ecbdata->diff_words->minus.text.size ||
1020             ecbdata->diff_words->plus.text.size)
1021                 diff_words_show(ecbdata->diff_words);
1022 }
1023
1024 static void diff_filespec_load_driver(struct diff_filespec *one)
1025 {
1026         /* Use already-loaded driver */
1027         if (one->driver)
1028                 return;
1029
1030         if (S_ISREG(one->mode))
1031                 one->driver = userdiff_find_by_path(one->path);
1032
1033         /* Fallback to default settings */
1034         if (!one->driver)
1035                 one->driver = userdiff_find_by_name("default");
1036 }
1037
1038 static const char *userdiff_word_regex(struct diff_filespec *one)
1039 {
1040         diff_filespec_load_driver(one);
1041         return one->driver->word_regex;
1042 }
1043
1044 static void init_diff_words_data(struct emit_callback *ecbdata,
1045                                  struct diff_options *orig_opts,
1046                                  struct diff_filespec *one,
1047                                  struct diff_filespec *two)
1048 {
1049         int i;
1050         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1051         memcpy(o, orig_opts, sizeof(struct diff_options));
1052
1053         ecbdata->diff_words =
1054                 xcalloc(1, sizeof(struct diff_words_data));
1055         ecbdata->diff_words->type = o->word_diff;
1056         ecbdata->diff_words->opt = o;
1057         if (!o->word_regex)
1058                 o->word_regex = userdiff_word_regex(one);
1059         if (!o->word_regex)
1060                 o->word_regex = userdiff_word_regex(two);
1061         if (!o->word_regex)
1062                 o->word_regex = diff_word_regex_cfg;
1063         if (o->word_regex) {
1064                 ecbdata->diff_words->word_regex = (regex_t *)
1065                         xmalloc(sizeof(regex_t));
1066                 if (regcomp(ecbdata->diff_words->word_regex,
1067                             o->word_regex,
1068                             REG_EXTENDED | REG_NEWLINE))
1069                         die ("Invalid regular expression: %s",
1070                              o->word_regex);
1071         }
1072         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1073                 if (o->word_diff == diff_words_styles[i].type) {
1074                         ecbdata->diff_words->style =
1075                                 &diff_words_styles[i];
1076                         break;
1077                 }
1078         }
1079         if (want_color(o->use_color)) {
1080                 struct diff_words_style *st = ecbdata->diff_words->style;
1081                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1082                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1083                 st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1084         }
1085 }
1086
1087 static void free_diff_words_data(struct emit_callback *ecbdata)
1088 {
1089         if (ecbdata->diff_words) {
1090                 diff_words_flush(ecbdata);
1091                 free (ecbdata->diff_words->opt);
1092                 free (ecbdata->diff_words->minus.text.ptr);
1093                 free (ecbdata->diff_words->minus.orig);
1094                 free (ecbdata->diff_words->plus.text.ptr);
1095                 free (ecbdata->diff_words->plus.orig);
1096                 if (ecbdata->diff_words->word_regex) {
1097                         regfree(ecbdata->diff_words->word_regex);
1098                         free(ecbdata->diff_words->word_regex);
1099                 }
1100                 free(ecbdata->diff_words);
1101                 ecbdata->diff_words = NULL;
1102         }
1103 }
1104
1105 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1106 {
1107         if (want_color(diff_use_color))
1108                 return diff_colors[ix];
1109         return "";
1110 }
1111
1112 const char *diff_line_prefix(struct diff_options *opt)
1113 {
1114         struct strbuf *msgbuf;
1115         if (!opt->output_prefix)
1116                 return "";
1117
1118         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1119         return msgbuf->buf;
1120 }
1121
1122 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1123 {
1124         const char *cp;
1125         unsigned long allot;
1126         size_t l = len;
1127
1128         if (ecb->truncate)
1129                 return ecb->truncate(line, len);
1130         cp = line;
1131         allot = l;
1132         while (0 < l) {
1133                 (void) utf8_width(&cp, &l);
1134                 if (!cp)
1135                         break; /* truncated in the middle? */
1136         }
1137         return allot - l;
1138 }
1139
1140 static void find_lno(const char *line, struct emit_callback *ecbdata)
1141 {
1142         const char *p;
1143         ecbdata->lno_in_preimage = 0;
1144         ecbdata->lno_in_postimage = 0;
1145         p = strchr(line, '-');
1146         if (!p)
1147                 return; /* cannot happen */
1148         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1149         p = strchr(p, '+');
1150         if (!p)
1151                 return; /* cannot happen */
1152         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1153 }
1154
1155 static void fn_out_consume(void *priv, char *line, unsigned long len)
1156 {
1157         struct emit_callback *ecbdata = priv;
1158         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1159         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1160         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1161         struct diff_options *o = ecbdata->opt;
1162         const char *line_prefix = diff_line_prefix(o);
1163
1164         if (ecbdata->header) {
1165                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1166                 strbuf_reset(ecbdata->header);
1167                 ecbdata->header = NULL;
1168         }
1169         *(ecbdata->found_changesp) = 1;
1170
1171         if (ecbdata->label_path[0]) {
1172                 const char *name_a_tab, *name_b_tab;
1173
1174                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1175                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1176
1177                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1178                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1179                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1180                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1181                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1182         }
1183
1184         if (diff_suppress_blank_empty
1185             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1186                 line[0] = '\n';
1187                 len = 1;
1188         }
1189
1190         if (line[0] == '@') {
1191                 if (ecbdata->diff_words)
1192                         diff_words_flush(ecbdata);
1193                 len = sane_truncate_line(ecbdata, line, len);
1194                 find_lno(line, ecbdata);
1195                 emit_hunk_header(ecbdata, line, len);
1196                 if (line[len-1] != '\n')
1197                         putc('\n', ecbdata->opt->file);
1198                 return;
1199         }
1200
1201         if (len < 1) {
1202                 emit_line(ecbdata->opt, reset, reset, line, len);
1203                 if (ecbdata->diff_words
1204                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1205                         fputs("~\n", ecbdata->opt->file);
1206                 return;
1207         }
1208
1209         if (ecbdata->diff_words) {
1210                 if (line[0] == '-') {
1211                         diff_words_append(line, len,
1212                                           &ecbdata->diff_words->minus);
1213                         return;
1214                 } else if (line[0] == '+') {
1215                         diff_words_append(line, len,
1216                                           &ecbdata->diff_words->plus);
1217                         return;
1218                 } else if (!prefixcmp(line, "\\ ")) {
1219                         /*
1220                          * Eat the "no newline at eof" marker as if we
1221                          * saw a "+" or "-" line with nothing on it,
1222                          * and return without diff_words_flush() to
1223                          * defer processing. If this is the end of
1224                          * preimage, more "+" lines may come after it.
1225                          */
1226                         return;
1227                 }
1228                 diff_words_flush(ecbdata);
1229                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1230                         emit_line(ecbdata->opt, plain, reset, line, len);
1231                         fputs("~\n", ecbdata->opt->file);
1232                 } else {
1233                         /*
1234                          * Skip the prefix character, if any.  With
1235                          * diff_suppress_blank_empty, there may be
1236                          * none.
1237                          */
1238                         if (line[0] != '\n') {
1239                               line++;
1240                               len--;
1241                         }
1242                         emit_line(ecbdata->opt, plain, reset, line, len);
1243                 }
1244                 return;
1245         }
1246
1247         if (line[0] != '+') {
1248                 const char *color =
1249                         diff_get_color(ecbdata->color_diff,
1250                                        line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1251                 ecbdata->lno_in_preimage++;
1252                 if (line[0] == ' ')
1253                         ecbdata->lno_in_postimage++;
1254                 emit_line(ecbdata->opt, color, reset, line, len);
1255         } else {
1256                 ecbdata->lno_in_postimage++;
1257                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1258         }
1259 }
1260
1261 static char *pprint_rename(const char *a, const char *b)
1262 {
1263         const char *old = a;
1264         const char *new = b;
1265         struct strbuf name = STRBUF_INIT;
1266         int pfx_length, sfx_length;
1267         int len_a = strlen(a);
1268         int len_b = strlen(b);
1269         int a_midlen, b_midlen;
1270         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1271         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1272
1273         if (qlen_a || qlen_b) {
1274                 quote_c_style(a, &name, NULL, 0);
1275                 strbuf_addstr(&name, " => ");
1276                 quote_c_style(b, &name, NULL, 0);
1277                 return strbuf_detach(&name, NULL);
1278         }
1279
1280         /* Find common prefix */
1281         pfx_length = 0;
1282         while (*old && *new && *old == *new) {
1283                 if (*old == '/')
1284                         pfx_length = old - a + 1;
1285                 old++;
1286                 new++;
1287         }
1288
1289         /* Find common suffix */
1290         old = a + len_a;
1291         new = b + len_b;
1292         sfx_length = 0;
1293         while (a <= old && b <= new && *old == *new) {
1294                 if (*old == '/')
1295                         sfx_length = len_a - (old - a);
1296                 old--;
1297                 new--;
1298         }
1299
1300         /*
1301          * pfx{mid-a => mid-b}sfx
1302          * {pfx-a => pfx-b}sfx
1303          * pfx{sfx-a => sfx-b}
1304          * name-a => name-b
1305          */
1306         a_midlen = len_a - pfx_length - sfx_length;
1307         b_midlen = len_b - pfx_length - sfx_length;
1308         if (a_midlen < 0)
1309                 a_midlen = 0;
1310         if (b_midlen < 0)
1311                 b_midlen = 0;
1312
1313         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1314         if (pfx_length + sfx_length) {
1315                 strbuf_add(&name, a, pfx_length);
1316                 strbuf_addch(&name, '{');
1317         }
1318         strbuf_add(&name, a + pfx_length, a_midlen);
1319         strbuf_addstr(&name, " => ");
1320         strbuf_add(&name, b + pfx_length, b_midlen);
1321         if (pfx_length + sfx_length) {
1322                 strbuf_addch(&name, '}');
1323                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1324         }
1325         return strbuf_detach(&name, NULL);
1326 }
1327
1328 struct diffstat_t {
1329         int nr;
1330         int alloc;
1331         struct diffstat_file {
1332                 char *from_name;
1333                 char *name;
1334                 char *print_name;
1335                 unsigned is_unmerged:1;
1336                 unsigned is_binary:1;
1337                 unsigned is_renamed:1;
1338                 unsigned is_interesting:1;
1339                 uintmax_t added, deleted;
1340         } **files;
1341 };
1342
1343 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1344                                           const char *name_a,
1345                                           const char *name_b)
1346 {
1347         struct diffstat_file *x;
1348         x = xcalloc(sizeof (*x), 1);
1349         if (diffstat->nr == diffstat->alloc) {
1350                 diffstat->alloc = alloc_nr(diffstat->alloc);
1351                 diffstat->files = xrealloc(diffstat->files,
1352                                 diffstat->alloc * sizeof(x));
1353         }
1354         diffstat->files[diffstat->nr++] = x;
1355         if (name_b) {
1356                 x->from_name = xstrdup(name_a);
1357                 x->name = xstrdup(name_b);
1358                 x->is_renamed = 1;
1359         }
1360         else {
1361                 x->from_name = NULL;
1362                 x->name = xstrdup(name_a);
1363         }
1364         return x;
1365 }
1366
1367 static void diffstat_consume(void *priv, char *line, unsigned long len)
1368 {
1369         struct diffstat_t *diffstat = priv;
1370         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1371
1372         if (line[0] == '+')
1373                 x->added++;
1374         else if (line[0] == '-')
1375                 x->deleted++;
1376 }
1377
1378 const char mime_boundary_leader[] = "------------";
1379
1380 static int scale_linear(int it, int width, int max_change)
1381 {
1382         if (!it)
1383                 return 0;
1384         /*
1385          * make sure that at least one '-' or '+' is printed if
1386          * there is any change to this path. The easiest way is to
1387          * scale linearly as if the alloted width is one column shorter
1388          * than it is, and then add 1 to the result.
1389          */
1390         return 1 + (it * (width - 1) / max_change);
1391 }
1392
1393 static void show_name(FILE *file,
1394                       const char *prefix, const char *name, int len)
1395 {
1396         fprintf(file, " %s%-*s |", prefix, len, name);
1397 }
1398
1399 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1400 {
1401         if (cnt <= 0)
1402                 return;
1403         fprintf(file, "%s", set);
1404         while (cnt--)
1405                 putc(ch, file);
1406         fprintf(file, "%s", reset);
1407 }
1408
1409 static void fill_print_name(struct diffstat_file *file)
1410 {
1411         char *pname;
1412
1413         if (file->print_name)
1414                 return;
1415
1416         if (!file->is_renamed) {
1417                 struct strbuf buf = STRBUF_INIT;
1418                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1419                         pname = strbuf_detach(&buf, NULL);
1420                 } else {
1421                         pname = file->name;
1422                         strbuf_release(&buf);
1423                 }
1424         } else {
1425                 pname = pprint_rename(file->from_name, file->name);
1426         }
1427         file->print_name = pname;
1428 }
1429
1430 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1431 {
1432         struct strbuf sb = STRBUF_INIT;
1433         int ret;
1434
1435         if (!files) {
1436                 assert(insertions == 0 && deletions == 0);
1437                 return fprintf(fp, "%s\n", " 0 files changed");
1438         }
1439
1440         strbuf_addf(&sb,
1441                     (files == 1) ? " %d file changed" : " %d files changed",
1442                     files);
1443
1444         /*
1445          * For binary diff, the caller may want to print "x files
1446          * changed" with insertions == 0 && deletions == 0.
1447          *
1448          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1449          * is probably less confusing (i.e skip over "2 files changed
1450          * but nothing about added/removed lines? Is this a bug in Git?").
1451          */
1452         if (insertions || deletions == 0) {
1453                 /*
1454                  * TRANSLATORS: "+" in (+) is a line addition marker;
1455                  * do not translate it.
1456                  */
1457                 strbuf_addf(&sb,
1458                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1459                             insertions);
1460         }
1461
1462         if (deletions || insertions == 0) {
1463                 /*
1464                  * TRANSLATORS: "-" in (-) is a line removal marker;
1465                  * do not translate it.
1466                  */
1467                 strbuf_addf(&sb,
1468                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1469                             deletions);
1470         }
1471         strbuf_addch(&sb, '\n');
1472         ret = fputs(sb.buf, fp);
1473         strbuf_release(&sb);
1474         return ret;
1475 }
1476
1477 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1478 {
1479         int i, len, add, del, adds = 0, dels = 0;
1480         uintmax_t max_change = 0, max_len = 0;
1481         int total_files = data->nr, count;
1482         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1483         const char *reset, *add_c, *del_c;
1484         const char *line_prefix = "";
1485         int extra_shown = 0;
1486
1487         if (data->nr == 0)
1488                 return;
1489
1490         line_prefix = diff_line_prefix(options);
1491         count = options->stat_count ? options->stat_count : data->nr;
1492
1493         reset = diff_get_color_opt(options, DIFF_RESET);
1494         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1495         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1496
1497         /*
1498          * Find the longest filename and max number of changes
1499          */
1500         for (i = 0; (i < count) && (i < data->nr); i++) {
1501                 struct diffstat_file *file = data->files[i];
1502                 uintmax_t change = file->added + file->deleted;
1503
1504                 if (!file->is_interesting && (change == 0)) {
1505                         count++; /* not shown == room for one more */
1506                         continue;
1507                 }
1508                 fill_print_name(file);
1509                 len = strlen(file->print_name);
1510                 if (max_len < len)
1511                         max_len = len;
1512
1513                 if (file->is_unmerged) {
1514                         /* "Unmerged" is 8 characters */
1515                         bin_width = bin_width < 8 ? 8 : bin_width;
1516                         continue;
1517                 }
1518                 if (file->is_binary) {
1519                         /* "Bin XXX -> YYY bytes" */
1520                         int w = 14 + decimal_width(file->added)
1521                                 + decimal_width(file->deleted);
1522                         bin_width = bin_width < w ? w : bin_width;
1523                         /* Display change counts aligned with "Bin" */
1524                         number_width = 3;
1525                         continue;
1526                 }
1527
1528                 if (max_change < change)
1529                         max_change = change;
1530         }
1531         count = i; /* where we can stop scanning in data->files[] */
1532
1533         /*
1534          * We have width = stat_width or term_columns() columns total.
1535          * We want a maximum of min(max_len, stat_name_width) for the name part.
1536          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1537          * We also need 1 for " " and 4 + decimal_width(max_change)
1538          * for " | NNNN " and one the empty column at the end, altogether
1539          * 6 + decimal_width(max_change).
1540          *
1541          * If there's not enough space, we will use the smaller of
1542          * stat_name_width (if set) and 5/8*width for the filename,
1543          * and the rest for constant elements + graph part, but no more
1544          * than stat_graph_width for the graph part.
1545          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1546          * for the standard terminal size).
1547          *
1548          * In other words: stat_width limits the maximum width, and
1549          * stat_name_width fixes the maximum width of the filename,
1550          * and is also used to divide available columns if there
1551          * aren't enough.
1552          *
1553          * Binary files are displayed with "Bin XXX -> YYY bytes"
1554          * instead of the change count and graph. This part is treated
1555          * similarly to the graph part, except that it is not
1556          * "scaled". If total width is too small to accomodate the
1557          * guaranteed minimum width of the filename part and the
1558          * separators and this message, this message will "overflow"
1559          * making the line longer than the maximum width.
1560          */
1561
1562         if (options->stat_width == -1)
1563                 width = term_columns() - options->output_prefix_length;
1564         else
1565                 width = options->stat_width ? options->stat_width : 80;
1566         number_width = decimal_width(max_change) > number_width ?
1567                 decimal_width(max_change) : number_width;
1568
1569         if (options->stat_graph_width == -1)
1570                 options->stat_graph_width = diff_stat_graph_width;
1571
1572         /*
1573          * Guarantee 3/8*16==6 for the graph part
1574          * and 5/8*16==10 for the filename part
1575          */
1576         if (width < 16 + 6 + number_width)
1577                 width = 16 + 6 + number_width;
1578
1579         /*
1580          * First assign sizes that are wanted, ignoring available width.
1581          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1582          * starting from "XXX" should fit in graph_width.
1583          */
1584         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1585         if (options->stat_graph_width &&
1586             options->stat_graph_width < graph_width)
1587                 graph_width = options->stat_graph_width;
1588
1589         name_width = (options->stat_name_width > 0 &&
1590                       options->stat_name_width < max_len) ?
1591                 options->stat_name_width : max_len;
1592
1593         /*
1594          * Adjust adjustable widths not to exceed maximum width
1595          */
1596         if (name_width + number_width + 6 + graph_width > width) {
1597                 if (graph_width > width * 3/8 - number_width - 6) {
1598                         graph_width = width * 3/8 - number_width - 6;
1599                         if (graph_width < 6)
1600                                 graph_width = 6;
1601                 }
1602
1603                 if (options->stat_graph_width &&
1604                     graph_width > options->stat_graph_width)
1605                         graph_width = options->stat_graph_width;
1606                 if (name_width > width - number_width - 6 - graph_width)
1607                         name_width = width - number_width - 6 - graph_width;
1608                 else
1609                         graph_width = width - number_width - 6 - name_width;
1610         }
1611
1612         /*
1613          * From here name_width is the width of the name area,
1614          * and graph_width is the width of the graph area.
1615          * max_change is used to scale graph properly.
1616          */
1617         for (i = 0; i < count; i++) {
1618                 const char *prefix = "";
1619                 struct diffstat_file *file = data->files[i];
1620                 char *name = file->print_name;
1621                 uintmax_t added = file->added;
1622                 uintmax_t deleted = file->deleted;
1623                 int name_len;
1624
1625                 if (!file->is_interesting && (added + deleted == 0))
1626                         continue;
1627
1628                 /*
1629                  * "scale" the filename
1630                  */
1631                 len = name_width;
1632                 name_len = strlen(name);
1633                 if (name_width < name_len) {
1634                         char *slash;
1635                         prefix = "...";
1636                         len -= 3;
1637                         name += name_len - len;
1638                         slash = strchr(name, '/');
1639                         if (slash)
1640                                 name = slash;
1641                 }
1642
1643                 if (file->is_binary) {
1644                         fprintf(options->file, "%s", line_prefix);
1645                         show_name(options->file, prefix, name, len);
1646                         fprintf(options->file, " %*s", number_width, "Bin");
1647                         if (!added && !deleted) {
1648                                 putc('\n', options->file);
1649                                 continue;
1650                         }
1651                         fprintf(options->file, " %s%"PRIuMAX"%s",
1652                                 del_c, deleted, reset);
1653                         fprintf(options->file, " -> ");
1654                         fprintf(options->file, "%s%"PRIuMAX"%s",
1655                                 add_c, added, reset);
1656                         fprintf(options->file, " bytes");
1657                         fprintf(options->file, "\n");
1658                         continue;
1659                 }
1660                 else if (file->is_unmerged) {
1661                         fprintf(options->file, "%s", line_prefix);
1662                         show_name(options->file, prefix, name, len);
1663                         fprintf(options->file, " Unmerged\n");
1664                         continue;
1665                 }
1666
1667                 /*
1668                  * scale the add/delete
1669                  */
1670                 add = added;
1671                 del = deleted;
1672
1673                 if (graph_width <= max_change) {
1674                         int total = add + del;
1675
1676                         total = scale_linear(add + del, graph_width, max_change);
1677                         if (total < 2 && add && del)
1678                                 /* width >= 2 due to the sanity check */
1679                                 total = 2;
1680                         if (add < del) {
1681                                 add = scale_linear(add, graph_width, max_change);
1682                                 del = total - add;
1683                         } else {
1684                                 del = scale_linear(del, graph_width, max_change);
1685                                 add = total - del;
1686                         }
1687                 }
1688                 fprintf(options->file, "%s", line_prefix);
1689                 show_name(options->file, prefix, name, len);
1690                 fprintf(options->file, " %*"PRIuMAX"%s",
1691                         number_width, added + deleted,
1692                         added + deleted ? " " : "");
1693                 show_graph(options->file, '+', add, add_c, reset);
1694                 show_graph(options->file, '-', del, del_c, reset);
1695                 fprintf(options->file, "\n");
1696         }
1697
1698         for (i = 0; i < data->nr; i++) {
1699                 struct diffstat_file *file = data->files[i];
1700                 uintmax_t added = file->added;
1701                 uintmax_t deleted = file->deleted;
1702
1703                 if (file->is_unmerged ||
1704                     (!file->is_interesting && (added + deleted == 0))) {
1705                         total_files--;
1706                         continue;
1707                 }
1708
1709                 if (!file->is_binary) {
1710                         adds += added;
1711                         dels += deleted;
1712                 }
1713                 if (i < count)
1714                         continue;
1715                 if (!extra_shown)
1716                         fprintf(options->file, "%s ...\n", line_prefix);
1717                 extra_shown = 1;
1718         }
1719         fprintf(options->file, "%s", line_prefix);
1720         print_stat_summary(options->file, total_files, adds, dels);
1721 }
1722
1723 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1724 {
1725         int i, adds = 0, dels = 0, total_files = data->nr;
1726
1727         if (data->nr == 0)
1728                 return;
1729
1730         for (i = 0; i < data->nr; i++) {
1731                 int added = data->files[i]->added;
1732                 int deleted= data->files[i]->deleted;
1733
1734                 if (data->files[i]->is_unmerged ||
1735                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1736                         total_files--;
1737                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1738                         adds += added;
1739                         dels += deleted;
1740                 }
1741         }
1742         fprintf(options->file, "%s", diff_line_prefix(options));
1743         print_stat_summary(options->file, total_files, adds, dels);
1744 }
1745
1746 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1747 {
1748         int i;
1749
1750         if (data->nr == 0)
1751                 return;
1752
1753         for (i = 0; i < data->nr; i++) {
1754                 struct diffstat_file *file = data->files[i];
1755
1756                 fprintf(options->file, "%s", diff_line_prefix(options));
1757
1758                 if (file->is_binary)
1759                         fprintf(options->file, "-\t-\t");
1760                 else
1761                         fprintf(options->file,
1762                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1763                                 file->added, file->deleted);
1764                 if (options->line_termination) {
1765                         fill_print_name(file);
1766                         if (!file->is_renamed)
1767                                 write_name_quoted(file->name, options->file,
1768                                                   options->line_termination);
1769                         else {
1770                                 fputs(file->print_name, options->file);
1771                                 putc(options->line_termination, options->file);
1772                         }
1773                 } else {
1774                         if (file->is_renamed) {
1775                                 putc('\0', options->file);
1776                                 write_name_quoted(file->from_name, options->file, '\0');
1777                         }
1778                         write_name_quoted(file->name, options->file, '\0');
1779                 }
1780         }
1781 }
1782
1783 struct dirstat_file {
1784         const char *name;
1785         unsigned long changed;
1786 };
1787
1788 struct dirstat_dir {
1789         struct dirstat_file *files;
1790         int alloc, nr, permille, cumulative;
1791 };
1792
1793 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1794                 unsigned long changed, const char *base, int baselen)
1795 {
1796         unsigned long this_dir = 0;
1797         unsigned int sources = 0;
1798         const char *line_prefix = diff_line_prefix(opt);
1799
1800         while (dir->nr) {
1801                 struct dirstat_file *f = dir->files;
1802                 int namelen = strlen(f->name);
1803                 unsigned long this;
1804                 char *slash;
1805
1806                 if (namelen < baselen)
1807                         break;
1808                 if (memcmp(f->name, base, baselen))
1809                         break;
1810                 slash = strchr(f->name + baselen, '/');
1811                 if (slash) {
1812                         int newbaselen = slash + 1 - f->name;
1813                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1814                         sources++;
1815                 } else {
1816                         this = f->changed;
1817                         dir->files++;
1818                         dir->nr--;
1819                         sources += 2;
1820                 }
1821                 this_dir += this;
1822         }
1823
1824         /*
1825          * We don't report dirstat's for
1826          *  - the top level
1827          *  - or cases where everything came from a single directory
1828          *    under this directory (sources == 1).
1829          */
1830         if (baselen && sources != 1) {
1831                 if (this_dir) {
1832                         int permille = this_dir * 1000 / changed;
1833                         if (permille >= dir->permille) {
1834                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1835                                         permille / 10, permille % 10, baselen, base);
1836                                 if (!dir->cumulative)
1837                                         return 0;
1838                         }
1839                 }
1840         }
1841         return this_dir;
1842 }
1843
1844 static int dirstat_compare(const void *_a, const void *_b)
1845 {
1846         const struct dirstat_file *a = _a;
1847         const struct dirstat_file *b = _b;
1848         return strcmp(a->name, b->name);
1849 }
1850
1851 static void show_dirstat(struct diff_options *options)
1852 {
1853         int i;
1854         unsigned long changed;
1855         struct dirstat_dir dir;
1856         struct diff_queue_struct *q = &diff_queued_diff;
1857
1858         dir.files = NULL;
1859         dir.alloc = 0;
1860         dir.nr = 0;
1861         dir.permille = options->dirstat_permille;
1862         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1863
1864         changed = 0;
1865         for (i = 0; i < q->nr; i++) {
1866                 struct diff_filepair *p = q->queue[i];
1867                 const char *name;
1868                 unsigned long copied, added, damage;
1869                 int content_changed;
1870
1871                 name = p->two->path ? p->two->path : p->one->path;
1872
1873                 if (p->one->sha1_valid && p->two->sha1_valid)
1874                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1875                 else
1876                         content_changed = 1;
1877
1878                 if (!content_changed) {
1879                         /*
1880                          * The SHA1 has not changed, so pre-/post-content is
1881                          * identical. We can therefore skip looking at the
1882                          * file contents altogether.
1883                          */
1884                         damage = 0;
1885                         goto found_damage;
1886                 }
1887
1888                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1889                         /*
1890                          * In --dirstat-by-file mode, we don't really need to
1891                          * look at the actual file contents at all.
1892                          * The fact that the SHA1 changed is enough for us to
1893                          * add this file to the list of results
1894                          * (with each file contributing equal damage).
1895                          */
1896                         damage = 1;
1897                         goto found_damage;
1898                 }
1899
1900                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1901                         diff_populate_filespec(p->one, 0);
1902                         diff_populate_filespec(p->two, 0);
1903                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1904                                                &copied, &added);
1905                         diff_free_filespec_data(p->one);
1906                         diff_free_filespec_data(p->two);
1907                 } else if (DIFF_FILE_VALID(p->one)) {
1908                         diff_populate_filespec(p->one, 1);
1909                         copied = added = 0;
1910                         diff_free_filespec_data(p->one);
1911                 } else if (DIFF_FILE_VALID(p->two)) {
1912                         diff_populate_filespec(p->two, 1);
1913                         copied = 0;
1914                         added = p->two->size;
1915                         diff_free_filespec_data(p->two);
1916                 } else
1917                         continue;
1918
1919                 /*
1920                  * Original minus copied is the removed material,
1921                  * added is the new material.  They are both damages
1922                  * made to the preimage.
1923                  * If the resulting damage is zero, we know that
1924                  * diffcore_count_changes() considers the two entries to
1925                  * be identical, but since content_changed is true, we
1926                  * know that there must have been _some_ kind of change,
1927                  * so we force all entries to have damage > 0.
1928                  */
1929                 damage = (p->one->size - copied) + added;
1930                 if (!damage)
1931                         damage = 1;
1932
1933 found_damage:
1934                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1935                 dir.files[dir.nr].name = name;
1936                 dir.files[dir.nr].changed = damage;
1937                 changed += damage;
1938                 dir.nr++;
1939         }
1940
1941         /* This can happen even with many files, if everything was renames */
1942         if (!changed)
1943                 return;
1944
1945         /* Show all directories with more than x% of the changes */
1946         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1947         gather_dirstat(options, &dir, changed, "", 0);
1948 }
1949
1950 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1951 {
1952         int i;
1953         unsigned long changed;
1954         struct dirstat_dir dir;
1955
1956         if (data->nr == 0)
1957                 return;
1958
1959         dir.files = NULL;
1960         dir.alloc = 0;
1961         dir.nr = 0;
1962         dir.permille = options->dirstat_permille;
1963         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1964
1965         changed = 0;
1966         for (i = 0; i < data->nr; i++) {
1967                 struct diffstat_file *file = data->files[i];
1968                 unsigned long damage = file->added + file->deleted;
1969                 if (file->is_binary)
1970                         /*
1971                          * binary files counts bytes, not lines. Must find some
1972                          * way to normalize binary bytes vs. textual lines.
1973                          * The following heuristic assumes that there are 64
1974                          * bytes per "line".
1975                          * This is stupid and ugly, but very cheap...
1976                          */
1977                         damage = (damage + 63) / 64;
1978                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1979                 dir.files[dir.nr].name = file->name;
1980                 dir.files[dir.nr].changed = damage;
1981                 changed += damage;
1982                 dir.nr++;
1983         }
1984
1985         /* This can happen even with many files, if everything was renames */
1986         if (!changed)
1987                 return;
1988
1989         /* Show all directories with more than x% of the changes */
1990         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1991         gather_dirstat(options, &dir, changed, "", 0);
1992 }
1993
1994 static void free_diffstat_info(struct diffstat_t *diffstat)
1995 {
1996         int i;
1997         for (i = 0; i < diffstat->nr; i++) {
1998                 struct diffstat_file *f = diffstat->files[i];
1999                 if (f->name != f->print_name)
2000                         free(f->print_name);
2001                 free(f->name);
2002                 free(f->from_name);
2003                 free(f);
2004         }
2005         free(diffstat->files);
2006 }
2007
2008 struct checkdiff_t {
2009         const char *filename;
2010         int lineno;
2011         int conflict_marker_size;
2012         struct diff_options *o;
2013         unsigned ws_rule;
2014         unsigned status;
2015 };
2016
2017 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2018 {
2019         char firstchar;
2020         int cnt;
2021
2022         if (len < marker_size + 1)
2023                 return 0;
2024         firstchar = line[0];
2025         switch (firstchar) {
2026         case '=': case '>': case '<': case '|':
2027                 break;
2028         default:
2029                 return 0;
2030         }
2031         for (cnt = 1; cnt < marker_size; cnt++)
2032                 if (line[cnt] != firstchar)
2033                         return 0;
2034         /* line[1] thru line[marker_size-1] are same as firstchar */
2035         if (len < marker_size + 1 || !isspace(line[marker_size]))
2036                 return 0;
2037         return 1;
2038 }
2039
2040 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2041 {
2042         struct checkdiff_t *data = priv;
2043         int marker_size = data->conflict_marker_size;
2044         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2045         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2046         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2047         char *err;
2048         const char *line_prefix;
2049
2050         assert(data->o);
2051         line_prefix = diff_line_prefix(data->o);
2052
2053         if (line[0] == '+') {
2054                 unsigned bad;
2055                 data->lineno++;
2056                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2057                         data->status |= 1;
2058                         fprintf(data->o->file,
2059                                 "%s%s:%d: leftover conflict marker\n",
2060                                 line_prefix, data->filename, data->lineno);
2061                 }
2062                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2063                 if (!bad)
2064                         return;
2065                 data->status |= bad;
2066                 err = whitespace_error_string(bad);
2067                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2068                         line_prefix, data->filename, data->lineno, err);
2069                 free(err);
2070                 emit_line(data->o, set, reset, line, 1);
2071                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2072                               data->o->file, set, reset, ws);
2073         } else if (line[0] == ' ') {
2074                 data->lineno++;
2075         } else if (line[0] == '@') {
2076                 char *plus = strchr(line, '+');
2077                 if (plus)
2078                         data->lineno = strtol(plus, NULL, 10) - 1;
2079                 else
2080                         die("invalid diff");
2081         }
2082 }
2083
2084 static unsigned char *deflate_it(char *data,
2085                                  unsigned long size,
2086                                  unsigned long *result_size)
2087 {
2088         int bound;
2089         unsigned char *deflated;
2090         git_zstream stream;
2091
2092         memset(&stream, 0, sizeof(stream));
2093         git_deflate_init(&stream, zlib_compression_level);
2094         bound = git_deflate_bound(&stream, size);
2095         deflated = xmalloc(bound);
2096         stream.next_out = deflated;
2097         stream.avail_out = bound;
2098
2099         stream.next_in = (unsigned char *)data;
2100         stream.avail_in = size;
2101         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2102                 ; /* nothing */
2103         git_deflate_end(&stream);
2104         *result_size = stream.total_out;
2105         return deflated;
2106 }
2107
2108 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2109                                   const char *prefix)
2110 {
2111         void *cp;
2112         void *delta;
2113         void *deflated;
2114         void *data;
2115         unsigned long orig_size;
2116         unsigned long delta_size;
2117         unsigned long deflate_size;
2118         unsigned long data_size;
2119
2120         /* We could do deflated delta, or we could do just deflated two,
2121          * whichever is smaller.
2122          */
2123         delta = NULL;
2124         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2125         if (one->size && two->size) {
2126                 delta = diff_delta(one->ptr, one->size,
2127                                    two->ptr, two->size,
2128                                    &delta_size, deflate_size);
2129                 if (delta) {
2130                         void *to_free = delta;
2131                         orig_size = delta_size;
2132                         delta = deflate_it(delta, delta_size, &delta_size);
2133                         free(to_free);
2134                 }
2135         }
2136
2137         if (delta && delta_size < deflate_size) {
2138                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2139                 free(deflated);
2140                 data = delta;
2141                 data_size = delta_size;
2142         }
2143         else {
2144                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2145                 free(delta);
2146                 data = deflated;
2147                 data_size = deflate_size;
2148         }
2149
2150         /* emit data encoded in base85 */
2151         cp = data;
2152         while (data_size) {
2153                 int bytes = (52 < data_size) ? 52 : data_size;
2154                 char line[70];
2155                 data_size -= bytes;
2156                 if (bytes <= 26)
2157                         line[0] = bytes + 'A' - 1;
2158                 else
2159                         line[0] = bytes - 26 + 'a' - 1;
2160                 encode_85(line + 1, cp, bytes);
2161                 cp = (char *) cp + bytes;
2162                 fprintf(file, "%s", prefix);
2163                 fputs(line, file);
2164                 fputc('\n', file);
2165         }
2166         fprintf(file, "%s\n", prefix);
2167         free(data);
2168 }
2169
2170 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2171                              const char *prefix)
2172 {
2173         fprintf(file, "%sGIT binary patch\n", prefix);
2174         emit_binary_diff_body(file, one, two, prefix);
2175         emit_binary_diff_body(file, two, one, prefix);
2176 }
2177
2178 int diff_filespec_is_binary(struct diff_filespec *one)
2179 {
2180         if (one->is_binary == -1) {
2181                 diff_filespec_load_driver(one);
2182                 if (one->driver->binary != -1)
2183                         one->is_binary = one->driver->binary;
2184                 else {
2185                         if (!one->data && DIFF_FILE_VALID(one))
2186                                 diff_populate_filespec(one, 0);
2187                         if (one->data)
2188                                 one->is_binary = buffer_is_binary(one->data,
2189                                                 one->size);
2190                         if (one->is_binary == -1)
2191                                 one->is_binary = 0;
2192                 }
2193         }
2194         return one->is_binary;
2195 }
2196
2197 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2198 {
2199         diff_filespec_load_driver(one);
2200         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2201 }
2202
2203 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2204 {
2205         if (!options->a_prefix)
2206                 options->a_prefix = a;
2207         if (!options->b_prefix)
2208                 options->b_prefix = b;
2209 }
2210
2211 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2212 {
2213         if (!DIFF_FILE_VALID(one))
2214                 return NULL;
2215
2216         diff_filespec_load_driver(one);
2217         return userdiff_get_textconv(one->driver);
2218 }
2219
2220 static void builtin_diff(const char *name_a,
2221                          const char *name_b,
2222                          struct diff_filespec *one,
2223                          struct diff_filespec *two,
2224                          const char *xfrm_msg,
2225                          int must_show_header,
2226                          struct diff_options *o,
2227                          int complete_rewrite)
2228 {
2229         mmfile_t mf1, mf2;
2230         const char *lbl[2];
2231         char *a_one, *b_two;
2232         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2233         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2234         const char *a_prefix, *b_prefix;
2235         struct userdiff_driver *textconv_one = NULL;
2236         struct userdiff_driver *textconv_two = NULL;
2237         struct strbuf header = STRBUF_INIT;
2238         const char *line_prefix = diff_line_prefix(o);
2239
2240         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2241                         (!one->mode || S_ISGITLINK(one->mode)) &&
2242                         (!two->mode || S_ISGITLINK(two->mode))) {
2243                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2244                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2245                 show_submodule_summary(o->file, one ? one->path : two->path,
2246                                 one->sha1, two->sha1, two->dirty_submodule,
2247                                 meta, del, add, reset);
2248                 return;
2249         }
2250
2251         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2252                 textconv_one = get_textconv(one);
2253                 textconv_two = get_textconv(two);
2254         }
2255
2256         diff_set_mnemonic_prefix(o, "a/", "b/");
2257         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2258                 a_prefix = o->b_prefix;
2259                 b_prefix = o->a_prefix;
2260         } else {
2261                 a_prefix = o->a_prefix;
2262                 b_prefix = o->b_prefix;
2263         }
2264
2265         /* Never use a non-valid filename anywhere if at all possible */
2266         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2267         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2268
2269         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2270         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2271         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2272         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2273         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2274         if (lbl[0][0] == '/') {
2275                 /* /dev/null */
2276                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2277                 if (xfrm_msg)
2278                         strbuf_addstr(&header, xfrm_msg);
2279                 must_show_header = 1;
2280         }
2281         else if (lbl[1][0] == '/') {
2282                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2283                 if (xfrm_msg)
2284                         strbuf_addstr(&header, xfrm_msg);
2285                 must_show_header = 1;
2286         }
2287         else {
2288                 if (one->mode != two->mode) {
2289                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2290                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2291                         must_show_header = 1;
2292                 }
2293                 if (xfrm_msg)
2294                         strbuf_addstr(&header, xfrm_msg);
2295
2296                 /*
2297                  * we do not run diff between different kind
2298                  * of objects.
2299                  */
2300                 if ((one->mode ^ two->mode) & S_IFMT)
2301                         goto free_ab_and_return;
2302                 if (complete_rewrite &&
2303                     (textconv_one || !diff_filespec_is_binary(one)) &&
2304                     (textconv_two || !diff_filespec_is_binary(two))) {
2305                         fprintf(o->file, "%s", header.buf);
2306                         strbuf_reset(&header);
2307                         emit_rewrite_diff(name_a, name_b, one, two,
2308                                                 textconv_one, textconv_two, o);
2309                         o->found_changes = 1;
2310                         goto free_ab_and_return;
2311                 }
2312         }
2313
2314         if (o->irreversible_delete && lbl[1][0] == '/') {
2315                 fprintf(o->file, "%s", header.buf);
2316                 strbuf_reset(&header);
2317                 goto free_ab_and_return;
2318         } else if (!DIFF_OPT_TST(o, TEXT) &&
2319             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2320               (!textconv_two && diff_filespec_is_binary(two)) )) {
2321                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2322                         die("unable to read files to diff");
2323                 /* Quite common confusing case */
2324                 if (mf1.size == mf2.size &&
2325                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2326                         if (must_show_header)
2327                                 fprintf(o->file, "%s", header.buf);
2328                         goto free_ab_and_return;
2329                 }
2330                 fprintf(o->file, "%s", header.buf);
2331                 strbuf_reset(&header);
2332                 if (DIFF_OPT_TST(o, BINARY))
2333                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2334                 else
2335                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2336                                 line_prefix, lbl[0], lbl[1]);
2337                 o->found_changes = 1;
2338         } else {
2339                 /* Crazy xdl interfaces.. */
2340                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2341                 xpparam_t xpp;
2342                 xdemitconf_t xecfg;
2343                 struct emit_callback ecbdata;
2344                 const struct userdiff_funcname *pe;
2345
2346                 if (must_show_header) {
2347                         fprintf(o->file, "%s", header.buf);
2348                         strbuf_reset(&header);
2349                 }
2350
2351                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2352                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2353
2354                 pe = diff_funcname_pattern(one);
2355                 if (!pe)
2356                         pe = diff_funcname_pattern(two);
2357
2358                 memset(&xpp, 0, sizeof(xpp));
2359                 memset(&xecfg, 0, sizeof(xecfg));
2360                 memset(&ecbdata, 0, sizeof(ecbdata));
2361                 ecbdata.label_path = lbl;
2362                 ecbdata.color_diff = want_color(o->use_color);
2363                 ecbdata.found_changesp = &o->found_changes;
2364                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2365                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2366                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2367                 ecbdata.opt = o;
2368                 ecbdata.header = header.len ? &header : NULL;
2369                 xpp.flags = o->xdl_opts;
2370                 xecfg.ctxlen = o->context;
2371                 xecfg.interhunkctxlen = o->interhunkcontext;
2372                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2373                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2374                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2375                 if (pe)
2376                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2377                 if (!diffopts)
2378                         ;
2379                 else if (!prefixcmp(diffopts, "--unified="))
2380                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2381                 else if (!prefixcmp(diffopts, "-u"))
2382                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2383                 if (o->word_diff)
2384                         init_diff_words_data(&ecbdata, o, one, two);
2385                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2386                               &xpp, &xecfg);
2387                 if (o->word_diff)
2388                         free_diff_words_data(&ecbdata);
2389                 if (textconv_one)
2390                         free(mf1.ptr);
2391                 if (textconv_two)
2392                         free(mf2.ptr);
2393                 xdiff_clear_find_func(&xecfg);
2394         }
2395
2396  free_ab_and_return:
2397         strbuf_release(&header);
2398         diff_free_filespec_data(one);
2399         diff_free_filespec_data(two);
2400         free(a_one);
2401         free(b_two);
2402         return;
2403 }
2404
2405 static void builtin_diffstat(const char *name_a, const char *name_b,
2406                              struct diff_filespec *one,
2407                              struct diff_filespec *two,
2408                              struct diffstat_t *diffstat,
2409                              struct diff_options *o,
2410                              struct diff_filepair *p)
2411 {
2412         mmfile_t mf1, mf2;
2413         struct diffstat_file *data;
2414         int same_contents;
2415         int complete_rewrite = 0;
2416
2417         if (!DIFF_PAIR_UNMERGED(p)) {
2418                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2419                         complete_rewrite = 1;
2420         }
2421
2422         data = diffstat_add(diffstat, name_a, name_b);
2423         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2424
2425         if (!one || !two) {
2426                 data->is_unmerged = 1;
2427                 return;
2428         }
2429
2430         same_contents = !hashcmp(one->sha1, two->sha1);
2431
2432         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2433                 data->is_binary = 1;
2434                 if (same_contents) {
2435                         data->added = 0;
2436                         data->deleted = 0;
2437                 } else {
2438                         data->added = diff_filespec_size(two);
2439                         data->deleted = diff_filespec_size(one);
2440                 }
2441         }
2442
2443         else if (complete_rewrite) {
2444                 diff_populate_filespec(one, 0);
2445                 diff_populate_filespec(two, 0);
2446                 data->deleted = count_lines(one->data, one->size);
2447                 data->added = count_lines(two->data, two->size);
2448         }
2449
2450         else if (!same_contents) {
2451                 /* Crazy xdl interfaces.. */
2452                 xpparam_t xpp;
2453                 xdemitconf_t xecfg;
2454
2455                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2456                         die("unable to read files to diff");
2457
2458                 memset(&xpp, 0, sizeof(xpp));
2459                 memset(&xecfg, 0, sizeof(xecfg));
2460                 xpp.flags = o->xdl_opts;
2461                 xecfg.ctxlen = o->context;
2462                 xecfg.interhunkctxlen = o->interhunkcontext;
2463                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2464                               &xpp, &xecfg);
2465         }
2466
2467         diff_free_filespec_data(one);
2468         diff_free_filespec_data(two);
2469 }
2470
2471 static void builtin_checkdiff(const char *name_a, const char *name_b,
2472                               const char *attr_path,
2473                               struct diff_filespec *one,
2474                               struct diff_filespec *two,
2475                               struct diff_options *o)
2476 {
2477         mmfile_t mf1, mf2;
2478         struct checkdiff_t data;
2479
2480         if (!two)
2481                 return;
2482
2483         memset(&data, 0, sizeof(data));
2484         data.filename = name_b ? name_b : name_a;
2485         data.lineno = 0;
2486         data.o = o;
2487         data.ws_rule = whitespace_rule(attr_path);
2488         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2489
2490         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2491                 die("unable to read files to diff");
2492
2493         /*
2494          * All the other codepaths check both sides, but not checking
2495          * the "old" side here is deliberate.  We are checking the newly
2496          * introduced changes, and as long as the "new" side is text, we
2497          * can and should check what it introduces.
2498          */
2499         if (diff_filespec_is_binary(two))
2500                 goto free_and_return;
2501         else {
2502                 /* Crazy xdl interfaces.. */
2503                 xpparam_t xpp;
2504                 xdemitconf_t xecfg;
2505
2506                 memset(&xpp, 0, sizeof(xpp));
2507                 memset(&xecfg, 0, sizeof(xecfg));
2508                 xecfg.ctxlen = 1; /* at least one context line */
2509                 xpp.flags = 0;
2510                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2511                               &xpp, &xecfg);
2512
2513                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2514                         struct emit_callback ecbdata;
2515                         int blank_at_eof;
2516
2517                         ecbdata.ws_rule = data.ws_rule;
2518                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2519                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2520
2521                         if (blank_at_eof) {
2522                                 static char *err;
2523                                 if (!err)
2524                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2525                                 fprintf(o->file, "%s:%d: %s.\n",
2526                                         data.filename, blank_at_eof, err);
2527                                 data.status = 1; /* report errors */
2528                         }
2529                 }
2530         }
2531  free_and_return:
2532         diff_free_filespec_data(one);
2533         diff_free_filespec_data(two);
2534         if (data.status)
2535                 DIFF_OPT_SET(o, CHECK_FAILED);
2536 }
2537
2538 struct diff_filespec *alloc_filespec(const char *path)
2539 {
2540         int namelen = strlen(path);
2541         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2542
2543         memset(spec, 0, sizeof(*spec));
2544         spec->path = (char *)(spec + 1);
2545         memcpy(spec->path, path, namelen+1);
2546         spec->count = 1;
2547         spec->is_binary = -1;
2548         return spec;
2549 }
2550
2551 void free_filespec(struct diff_filespec *spec)
2552 {
2553         if (!--spec->count) {
2554                 diff_free_filespec_data(spec);
2555                 free(spec);
2556         }
2557 }
2558
2559 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2560                    int sha1_valid, unsigned short mode)
2561 {
2562         if (mode) {
2563                 spec->mode = canon_mode(mode);
2564                 hashcpy(spec->sha1, sha1);
2565                 spec->sha1_valid = sha1_valid;
2566         }
2567 }
2568
2569 /*
2570  * Given a name and sha1 pair, if the index tells us the file in
2571  * the work tree has that object contents, return true, so that
2572  * prepare_temp_file() does not have to inflate and extract.
2573  */
2574 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2575 {
2576         struct cache_entry *ce;
2577         struct stat st;
2578         int pos, len;
2579
2580         /*
2581          * We do not read the cache ourselves here, because the
2582          * benchmark with my previous version that always reads cache
2583          * shows that it makes things worse for diff-tree comparing
2584          * two linux-2.6 kernel trees in an already checked out work
2585          * tree.  This is because most diff-tree comparisons deal with
2586          * only a small number of files, while reading the cache is
2587          * expensive for a large project, and its cost outweighs the
2588          * savings we get by not inflating the object to a temporary
2589          * file.  Practically, this code only helps when we are used
2590          * by diff-cache --cached, which does read the cache before
2591          * calling us.
2592          */
2593         if (!active_cache)
2594                 return 0;
2595
2596         /* We want to avoid the working directory if our caller
2597          * doesn't need the data in a normal file, this system
2598          * is rather slow with its stat/open/mmap/close syscalls,
2599          * and the object is contained in a pack file.  The pack
2600          * is probably already open and will be faster to obtain
2601          * the data through than the working directory.  Loose
2602          * objects however would tend to be slower as they need
2603          * to be individually opened and inflated.
2604          */
2605         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2606                 return 0;
2607
2608         len = strlen(name);
2609         pos = cache_name_pos(name, len);
2610         if (pos < 0)
2611                 return 0;
2612         ce = active_cache[pos];
2613
2614         /*
2615          * This is not the sha1 we are looking for, or
2616          * unreusable because it is not a regular file.
2617          */
2618         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2619                 return 0;
2620
2621         /*
2622          * If ce is marked as "assume unchanged", there is no
2623          * guarantee that work tree matches what we are looking for.
2624          */
2625         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2626                 return 0;
2627
2628         /*
2629          * If ce matches the file in the work tree, we can reuse it.
2630          */
2631         if (ce_uptodate(ce) ||
2632             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2633                 return 1;
2634
2635         return 0;
2636 }
2637
2638 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2639 {
2640         int len;
2641         char *data = xmalloc(100), *dirty = "";
2642
2643         /* Are we looking at the work tree? */
2644         if (s->dirty_submodule)
2645                 dirty = "-dirty";
2646
2647         len = snprintf(data, 100,
2648                        "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2649         s->data = data;
2650         s->size = len;
2651         s->should_free = 1;
2652         if (size_only) {
2653                 s->data = NULL;
2654                 free(data);
2655         }
2656         return 0;
2657 }
2658
2659 /*
2660  * While doing rename detection and pickaxe operation, we may need to
2661  * grab the data for the blob (or file) for our own in-core comparison.
2662  * diff_filespec has data and size fields for this purpose.
2663  */
2664 int diff_populate_filespec(struct diff_filespec *s, int size_only)
2665 {
2666         int err = 0;
2667         if (!DIFF_FILE_VALID(s))
2668                 die("internal error: asking to populate invalid file.");
2669         if (S_ISDIR(s->mode))
2670                 return -1;
2671
2672         if (s->data)
2673                 return 0;
2674
2675         if (size_only && 0 < s->size)
2676                 return 0;
2677
2678         if (S_ISGITLINK(s->mode))
2679                 return diff_populate_gitlink(s, size_only);
2680
2681         if (!s->sha1_valid ||
2682             reuse_worktree_file(s->path, s->sha1, 0)) {
2683                 struct strbuf buf = STRBUF_INIT;
2684                 struct stat st;
2685                 int fd;
2686
2687                 if (lstat(s->path, &st) < 0) {
2688                         if (errno == ENOENT) {
2689                         err_empty:
2690                                 err = -1;
2691                         empty:
2692                                 s->data = (char *)"";
2693                                 s->size = 0;
2694                                 return err;
2695                         }
2696                 }
2697                 s->size = xsize_t(st.st_size);
2698                 if (!s->size)
2699                         goto empty;
2700                 if (S_ISLNK(st.st_mode)) {
2701                         struct strbuf sb = STRBUF_INIT;
2702
2703                         if (strbuf_readlink(&sb, s->path, s->size))
2704                                 goto err_empty;
2705                         s->size = sb.len;
2706                         s->data = strbuf_detach(&sb, NULL);
2707                         s->should_free = 1;
2708                         return 0;
2709                 }
2710                 if (size_only)
2711                         return 0;
2712                 fd = open(s->path, O_RDONLY);
2713                 if (fd < 0)
2714                         goto err_empty;
2715                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2716                 close(fd);
2717                 s->should_munmap = 1;
2718
2719                 /*
2720                  * Convert from working tree format to canonical git format
2721                  */
2722                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2723                         size_t size = 0;
2724                         munmap(s->data, s->size);
2725                         s->should_munmap = 0;
2726                         s->data = strbuf_detach(&buf, &size);
2727                         s->size = size;
2728                         s->should_free = 1;
2729                 }
2730         }
2731         else {
2732                 enum object_type type;
2733                 if (size_only) {
2734                         type = sha1_object_info(s->sha1, &s->size);
2735                         if (type < 0)
2736                                 die("unable to read %s", sha1_to_hex(s->sha1));
2737                 } else {
2738                         s->data = read_sha1_file(s->sha1, &type, &s->size);
2739                         if (!s->data)
2740                                 die("unable to read %s", sha1_to_hex(s->sha1));
2741                         s->should_free = 1;
2742                 }
2743         }
2744         return 0;
2745 }
2746
2747 void diff_free_filespec_blob(struct diff_filespec *s)
2748 {
2749         if (s->should_free)
2750                 free(s->data);
2751         else if (s->should_munmap)
2752                 munmap(s->data, s->size);
2753
2754         if (s->should_free || s->should_munmap) {
2755                 s->should_free = s->should_munmap = 0;
2756                 s->data = NULL;
2757         }
2758 }
2759
2760 void diff_free_filespec_data(struct diff_filespec *s)
2761 {
2762         diff_free_filespec_blob(s);
2763         free(s->cnt_data);
2764         s->cnt_data = NULL;
2765 }
2766
2767 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2768                            void *blob,
2769                            unsigned long size,
2770                            const unsigned char *sha1,
2771                            int mode)
2772 {
2773         int fd;
2774         struct strbuf buf = STRBUF_INIT;
2775         struct strbuf template = STRBUF_INIT;
2776         char *path_dup = xstrdup(path);
2777         const char *base = basename(path_dup);
2778
2779         /* Generate "XXXXXX_basename.ext" */
2780         strbuf_addstr(&template, "XXXXXX_");
2781         strbuf_addstr(&template, base);
2782
2783         fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2784                         strlen(base) + 1);
2785         if (fd < 0)
2786                 die_errno("unable to create temp-file");
2787         if (convert_to_working_tree(path,
2788                         (const char *)blob, (size_t)size, &buf)) {
2789                 blob = buf.buf;
2790                 size = buf.len;
2791         }
2792         if (write_in_full(fd, blob, size) != size)
2793                 die_errno("unable to write temp-file");
2794         close(fd);
2795         temp->name = temp->tmp_path;
2796         strcpy(temp->hex, sha1_to_hex(sha1));
2797         temp->hex[40] = 0;
2798         sprintf(temp->mode, "%06o", mode);
2799         strbuf_release(&buf);
2800         strbuf_release(&template);
2801         free(path_dup);
2802 }
2803
2804 static struct diff_tempfile *prepare_temp_file(const char *name,
2805                 struct diff_filespec *one)
2806 {
2807         struct diff_tempfile *temp = claim_diff_tempfile();
2808
2809         if (!DIFF_FILE_VALID(one)) {
2810         not_a_valid_file:
2811                 /* A '-' entry produces this for file-2, and
2812                  * a '+' entry produces this for file-1.
2813                  */
2814                 temp->name = "/dev/null";
2815                 strcpy(temp->hex, ".");
2816                 strcpy(temp->mode, ".");
2817                 return temp;
2818         }
2819
2820         if (!remove_tempfile_installed) {
2821                 atexit(remove_tempfile);
2822                 sigchain_push_common(remove_tempfile_on_signal);
2823                 remove_tempfile_installed = 1;
2824         }
2825
2826         if (!one->sha1_valid ||
2827             reuse_worktree_file(name, one->sha1, 1)) {
2828                 struct stat st;
2829                 if (lstat(name, &st) < 0) {
2830                         if (errno == ENOENT)
2831                                 goto not_a_valid_file;
2832                         die_errno("stat(%s)", name);
2833                 }
2834                 if (S_ISLNK(st.st_mode)) {
2835                         struct strbuf sb = STRBUF_INIT;
2836                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2837                                 die_errno("readlink(%s)", name);
2838                         prep_temp_blob(name, temp, sb.buf, sb.len,
2839                                        (one->sha1_valid ?
2840                                         one->sha1 : null_sha1),
2841                                        (one->sha1_valid ?
2842                                         one->mode : S_IFLNK));
2843                         strbuf_release(&sb);
2844                 }
2845                 else {
2846                         /* we can borrow from the file in the work tree */
2847                         temp->name = name;
2848                         if (!one->sha1_valid)
2849                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
2850                         else
2851                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
2852                         /* Even though we may sometimes borrow the
2853                          * contents from the work tree, we always want
2854                          * one->mode.  mode is trustworthy even when
2855                          * !(one->sha1_valid), as long as
2856                          * DIFF_FILE_VALID(one).
2857                          */
2858                         sprintf(temp->mode, "%06o", one->mode);
2859                 }
2860                 return temp;
2861         }
2862         else {
2863                 if (diff_populate_filespec(one, 0))
2864                         die("cannot read data blob for %s", one->path);
2865                 prep_temp_blob(name, temp, one->data, one->size,
2866                                one->sha1, one->mode);
2867         }
2868         return temp;
2869 }
2870
2871 /* An external diff command takes:
2872  *
2873  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2874  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2875  *
2876  */
2877 static void run_external_diff(const char *pgm,
2878                               const char *name,
2879                               const char *other,
2880                               struct diff_filespec *one,
2881                               struct diff_filespec *two,
2882                               const char *xfrm_msg,
2883                               int complete_rewrite)
2884 {
2885         const char *spawn_arg[10];
2886         int retval;
2887         const char **arg = &spawn_arg[0];
2888
2889         if (one && two) {
2890                 struct diff_tempfile *temp_one, *temp_two;
2891                 const char *othername = (other ? other : name);
2892                 temp_one = prepare_temp_file(name, one);
2893                 temp_two = prepare_temp_file(othername, two);
2894                 *arg++ = pgm;
2895                 *arg++ = name;
2896                 *arg++ = temp_one->name;
2897                 *arg++ = temp_one->hex;
2898                 *arg++ = temp_one->mode;
2899                 *arg++ = temp_two->name;
2900                 *arg++ = temp_two->hex;
2901                 *arg++ = temp_two->mode;
2902                 if (other) {
2903                         *arg++ = other;
2904                         *arg++ = xfrm_msg;
2905                 }
2906         } else {
2907                 *arg++ = pgm;
2908                 *arg++ = name;
2909         }
2910         *arg = NULL;
2911         fflush(NULL);
2912         retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2913         remove_tempfile();
2914         if (retval) {
2915                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2916                 exit(1);
2917         }
2918 }
2919
2920 static int similarity_index(struct diff_filepair *p)
2921 {
2922         return p->score * 100 / MAX_SCORE;
2923 }
2924
2925 static void fill_metainfo(struct strbuf *msg,
2926                           const char *name,
2927                           const char *other,
2928                           struct diff_filespec *one,
2929                           struct diff_filespec *two,
2930                           struct diff_options *o,
2931                           struct diff_filepair *p,
2932                           int *must_show_header,
2933                           int use_color)
2934 {
2935         const char *set = diff_get_color(use_color, DIFF_METAINFO);
2936         const char *reset = diff_get_color(use_color, DIFF_RESET);
2937         const char *line_prefix = diff_line_prefix(o);
2938
2939         *must_show_header = 1;
2940         strbuf_init(msg, PATH_MAX * 2 + 300);
2941         switch (p->status) {
2942         case DIFF_STATUS_COPIED:
2943                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2944                             line_prefix, set, similarity_index(p));
2945                 strbuf_addf(msg, "%s\n%s%scopy from ",
2946                             reset,  line_prefix, set);
2947                 quote_c_style(name, msg, NULL, 0);
2948                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2949                 quote_c_style(other, msg, NULL, 0);
2950                 strbuf_addf(msg, "%s\n", reset);
2951                 break;
2952         case DIFF_STATUS_RENAMED:
2953                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2954                             line_prefix, set, similarity_index(p));
2955                 strbuf_addf(msg, "%s\n%s%srename from ",
2956                             reset, line_prefix, set);
2957                 quote_c_style(name, msg, NULL, 0);
2958                 strbuf_addf(msg, "%s\n%s%srename to ",
2959                             reset, line_prefix, set);
2960                 quote_c_style(other, msg, NULL, 0);
2961                 strbuf_addf(msg, "%s\n", reset);
2962                 break;
2963         case DIFF_STATUS_MODIFIED:
2964                 if (p->score) {
2965                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2966                                     line_prefix,
2967                                     set, similarity_index(p), reset);
2968                         break;
2969                 }
2970                 /* fallthru */
2971         default:
2972                 *must_show_header = 0;
2973         }
2974         if (one && two && hashcmp(one->sha1, two->sha1)) {
2975                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2976
2977                 if (DIFF_OPT_TST(o, BINARY)) {
2978                         mmfile_t mf;
2979                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2980                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2981                                 abbrev = 40;
2982                 }
2983                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2984                             find_unique_abbrev(one->sha1, abbrev));
2985                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2986                 if (one->mode == two->mode)
2987                         strbuf_addf(msg, " %06o", one->mode);
2988                 strbuf_addf(msg, "%s\n", reset);
2989         }
2990 }
2991
2992 static void run_diff_cmd(const char *pgm,
2993                          const char *name,
2994                          const char *other,
2995                          const char *attr_path,
2996                          struct diff_filespec *one,
2997                          struct diff_filespec *two,
2998                          struct strbuf *msg,
2999                          struct diff_options *o,
3000                          struct diff_filepair *p)
3001 {
3002         const char *xfrm_msg = NULL;
3003         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3004         int must_show_header = 0;
3005
3006
3007         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3008                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3009                 if (drv && drv->external)
3010                         pgm = drv->external;
3011         }
3012
3013         if (msg) {
3014                 /*
3015                  * don't use colors when the header is intended for an
3016                  * external diff driver
3017                  */
3018                 fill_metainfo(msg, name, other, one, two, o, p,
3019                               &must_show_header,
3020                               want_color(o->use_color) && !pgm);
3021                 xfrm_msg = msg->len ? msg->buf : NULL;
3022         }
3023
3024         if (pgm) {
3025                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3026                                   complete_rewrite);
3027                 return;
3028         }
3029         if (one && two)
3030                 builtin_diff(name, other ? other : name,
3031                              one, two, xfrm_msg, must_show_header,
3032                              o, complete_rewrite);
3033         else
3034                 fprintf(o->file, "* Unmerged path %s\n", name);
3035 }
3036
3037 static void diff_fill_sha1_info(struct diff_filespec *one)
3038 {
3039         if (DIFF_FILE_VALID(one)) {
3040                 if (!one->sha1_valid) {
3041                         struct stat st;
3042                         if (one->is_stdin) {
3043                                 hashcpy(one->sha1, null_sha1);
3044                                 return;
3045                         }
3046                         if (lstat(one->path, &st) < 0)
3047                                 die_errno("stat '%s'", one->path);
3048                         if (index_path(one->sha1, one->path, &st, 0))
3049                                 die("cannot hash %s", one->path);
3050                 }
3051         }
3052         else
3053                 hashclr(one->sha1);
3054 }
3055
3056 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3057 {
3058         /* Strip the prefix but do not molest /dev/null and absolute paths */
3059         if (*namep && **namep != '/') {
3060                 *namep += prefix_length;
3061                 if (**namep == '/')
3062                         ++*namep;
3063         }
3064         if (*otherp && **otherp != '/') {
3065                 *otherp += prefix_length;
3066                 if (**otherp == '/')
3067                         ++*otherp;
3068         }
3069 }
3070
3071 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3072 {
3073         const char *pgm = external_diff();
3074         struct strbuf msg;
3075         struct diff_filespec *one = p->one;
3076         struct diff_filespec *two = p->two;
3077         const char *name;
3078         const char *other;
3079         const char *attr_path;
3080
3081         name  = p->one->path;
3082         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3083         attr_path = name;
3084         if (o->prefix_length)
3085                 strip_prefix(o->prefix_length, &name, &other);
3086
3087         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3088                 pgm = NULL;
3089
3090         if (DIFF_PAIR_UNMERGED(p)) {
3091                 run_diff_cmd(pgm, name, NULL, attr_path,
3092                              NULL, NULL, NULL, o, p);
3093                 return;
3094         }
3095
3096         diff_fill_sha1_info(one);
3097         diff_fill_sha1_info(two);
3098
3099         if (!pgm &&
3100             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3101             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3102                 /*
3103                  * a filepair that changes between file and symlink
3104                  * needs to be split into deletion and creation.
3105                  */
3106                 struct diff_filespec *null = alloc_filespec(two->path);
3107                 run_diff_cmd(NULL, name, other, attr_path,
3108                              one, null, &msg, o, p);
3109                 free(null);
3110                 strbuf_release(&msg);
3111
3112                 null = alloc_filespec(one->path);
3113                 run_diff_cmd(NULL, name, other, attr_path,
3114                              null, two, &msg, o, p);
3115                 free(null);
3116         }
3117         else
3118                 run_diff_cmd(pgm, name, other, attr_path,
3119                              one, two, &msg, o, p);
3120
3121         strbuf_release(&msg);
3122 }
3123
3124 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3125                          struct diffstat_t *diffstat)
3126 {
3127         const char *name;
3128         const char *other;
3129
3130         if (DIFF_PAIR_UNMERGED(p)) {
3131                 /* unmerged */
3132                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3133                 return;
3134         }
3135
3136         name = p->one->path;
3137         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3138
3139         if (o->prefix_length)
3140                 strip_prefix(o->prefix_length, &name, &other);
3141
3142         diff_fill_sha1_info(p->one);
3143         diff_fill_sha1_info(p->two);
3144
3145         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3146 }
3147
3148 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3149 {
3150         const char *name;
3151         const char *other;
3152         const char *attr_path;
3153
3154         if (DIFF_PAIR_UNMERGED(p)) {
3155                 /* unmerged */
3156                 return;
3157         }
3158
3159         name = p->one->path;
3160         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3161         attr_path = other ? other : name;
3162
3163         if (o->prefix_length)
3164                 strip_prefix(o->prefix_length, &name, &other);
3165
3166         diff_fill_sha1_info(p->one);
3167         diff_fill_sha1_info(p->two);
3168
3169         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3170 }
3171
3172 void diff_setup(struct diff_options *options)
3173 {
3174         memcpy(options, &default_diff_options, sizeof(*options));
3175
3176         options->file = stdout;
3177
3178         options->line_termination = '\n';
3179         options->break_opt = -1;
3180         options->rename_limit = -1;
3181         options->dirstat_permille = diff_dirstat_permille_default;
3182         options->context = diff_context_default;
3183         DIFF_OPT_SET(options, RENAME_EMPTY);
3184
3185         options->change = diff_change;
3186         options->add_remove = diff_addremove;
3187         options->use_color = diff_use_color_default;
3188         options->detect_rename = diff_detect_rename_default;
3189         options->xdl_opts |= diff_algorithm;
3190
3191         if (diff_no_prefix) {
3192                 options->a_prefix = options->b_prefix = "";
3193         } else if (!diff_mnemonic_prefix) {
3194                 options->a_prefix = "a/";
3195                 options->b_prefix = "b/";
3196         }
3197 }
3198
3199 void diff_setup_done(struct diff_options *options)
3200 {
3201         int count = 0;
3202
3203         if (options->output_format & DIFF_FORMAT_NAME)
3204                 count++;
3205         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3206                 count++;
3207         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3208                 count++;
3209         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3210                 count++;
3211         if (count > 1)
3212                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3213
3214         /*
3215          * Most of the time we can say "there are changes"
3216          * only by checking if there are changed paths, but
3217          * --ignore-whitespace* options force us to look
3218          * inside contents.
3219          */
3220
3221         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3222             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3223             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3224                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3225         else
3226                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3227
3228         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3229                 options->detect_rename = DIFF_DETECT_COPY;
3230
3231         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3232                 options->prefix = NULL;
3233         if (options->prefix)
3234                 options->prefix_length = strlen(options->prefix);
3235         else
3236                 options->prefix_length = 0;
3237
3238         if (options->output_format & (DIFF_FORMAT_NAME |
3239                                       DIFF_FORMAT_NAME_STATUS |
3240                                       DIFF_FORMAT_CHECKDIFF |
3241                                       DIFF_FORMAT_NO_OUTPUT))
3242                 options->output_format &= ~(DIFF_FORMAT_RAW |
3243                                             DIFF_FORMAT_NUMSTAT |
3244                                             DIFF_FORMAT_DIFFSTAT |
3245                                             DIFF_FORMAT_SHORTSTAT |
3246                                             DIFF_FORMAT_DIRSTAT |
3247                                             DIFF_FORMAT_SUMMARY |
3248                                             DIFF_FORMAT_PATCH);
3249
3250         /*
3251          * These cases always need recursive; we do not drop caller-supplied
3252          * recursive bits for other formats here.
3253          */
3254         if (options->output_format & (DIFF_FORMAT_PATCH |
3255                                       DIFF_FORMAT_NUMSTAT |
3256                                       DIFF_FORMAT_DIFFSTAT |
3257                                       DIFF_FORMAT_SHORTSTAT |
3258                                       DIFF_FORMAT_DIRSTAT |
3259                                       DIFF_FORMAT_SUMMARY |
3260                                       DIFF_FORMAT_CHECKDIFF))
3261                 DIFF_OPT_SET(options, RECURSIVE);
3262         /*
3263          * Also pickaxe would not work very well if you do not say recursive
3264          */
3265         if (options->pickaxe)
3266                 DIFF_OPT_SET(options, RECURSIVE);
3267         /*
3268          * When patches are generated, submodules diffed against the work tree
3269          * must be checked for dirtiness too so it can be shown in the output
3270          */
3271         if (options->output_format & DIFF_FORMAT_PATCH)
3272                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3273
3274         if (options->detect_rename && options->rename_limit < 0)
3275                 options->rename_limit = diff_rename_limit_default;
3276         if (options->setup & DIFF_SETUP_USE_CACHE) {
3277                 if (!active_cache)
3278                         /* read-cache does not die even when it fails
3279                          * so it is safe for us to do this here.  Also
3280                          * it does not smudge active_cache or active_nr
3281                          * when it fails, so we do not have to worry about
3282                          * cleaning it up ourselves either.
3283                          */
3284                         read_cache();
3285         }
3286         if (options->abbrev <= 0 || 40 < options->abbrev)
3287                 options->abbrev = 40; /* full */
3288
3289         /*
3290          * It does not make sense to show the first hit we happened
3291          * to have found.  It does not make sense not to return with
3292          * exit code in such a case either.
3293          */
3294         if (DIFF_OPT_TST(options, QUICK)) {
3295                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3296                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3297         }
3298 }
3299
3300 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3301 {
3302         char c, *eq;
3303         int len;
3304
3305         if (*arg != '-')
3306                 return 0;
3307         c = *++arg;
3308         if (!c)
3309                 return 0;
3310         if (c == arg_short) {
3311                 c = *++arg;
3312                 if (!c)
3313                         return 1;
3314                 if (val && isdigit(c)) {
3315                         char *end;
3316                         int n = strtoul(arg, &end, 10);
3317                         if (*end)
3318                                 return 0;
3319                         *val = n;
3320                         return 1;
3321                 }
3322                 return 0;
3323         }
3324         if (c != '-')
3325                 return 0;
3326         arg++;
3327         eq = strchr(arg, '=');
3328         if (eq)
3329                 len = eq - arg;
3330         else
3331                 len = strlen(arg);
3332         if (!len || strncmp(arg, arg_long, len))
3333                 return 0;
3334         if (eq) {
3335                 int n;
3336                 char *end;
3337                 if (!isdigit(*++eq))
3338                         return 0;
3339                 n = strtoul(eq, &end, 10);
3340                 if (*end)
3341                         return 0;
3342                 *val = n;
3343         }
3344         return 1;
3345 }
3346
3347 static int diff_scoreopt_parse(const char *opt);
3348
3349 static inline int short_opt(char opt, const char **argv,
3350                             const char **optarg)
3351 {
3352         const char *arg = argv[0];
3353         if (arg[0] != '-' || arg[1] != opt)
3354                 return 0;
3355         if (arg[2] != '\0') {
3356                 *optarg = arg + 2;
3357                 return 1;
3358         }
3359         if (!argv[1])
3360                 die("Option '%c' requires a value", opt);
3361         *optarg = argv[1];
3362         return 2;
3363 }
3364
3365 int parse_long_opt(const char *opt, const char **argv,
3366                    const char **optarg)
3367 {
3368         const char *arg = argv[0];
3369         if (arg[0] != '-' || arg[1] != '-')
3370                 return 0;
3371         arg += strlen("--");
3372         if (prefixcmp(arg, opt))
3373                 return 0;
3374         arg += strlen(opt);
3375         if (*arg == '=') { /* sticked form: --option=value */
3376                 *optarg = arg + 1;
3377                 return 1;
3378         }
3379         if (*arg != '\0')
3380                 return 0;
3381         /* separate form: --option value */
3382         if (!argv[1])
3383                 die("Option '--%s' requires a value", opt);
3384         *optarg = argv[1];
3385         return 2;
3386 }
3387
3388 static int stat_opt(struct diff_options *options, const char **av)
3389 {
3390         const char *arg = av[0];
3391         char *end;
3392         int width = options->stat_width;
3393         int name_width = options->stat_name_width;
3394         int graph_width = options->stat_graph_width;
3395         int count = options->stat_count;
3396         int argcount = 1;
3397
3398         arg += strlen("--stat");
3399         end = (char *)arg;
3400
3401         switch (*arg) {
3402         case '-':
3403                 if (!prefixcmp(arg, "-width")) {
3404                         arg += strlen("-width");
3405                         if (*arg == '=')
3406                                 width = strtoul(arg + 1, &end, 10);
3407                         else if (!*arg && !av[1])
3408                                 die("Option '--stat-width' requires a value");
3409                         else if (!*arg) {
3410                                 width = strtoul(av[1], &end, 10);
3411                                 argcount = 2;
3412                         }
3413                 } else if (!prefixcmp(arg, "-name-width")) {
3414                         arg += strlen("-name-width");
3415                         if (*arg == '=')
3416                                 name_width = strtoul(arg + 1, &end, 10);
3417                         else if (!*arg && !av[1])
3418                                 die("Option '--stat-name-width' requires a value");
3419                         else if (!*arg) {
3420                                 name_width = strtoul(av[1], &end, 10);
3421                                 argcount = 2;
3422                         }
3423                 } else if (!prefixcmp(arg, "-graph-width")) {
3424                         arg += strlen("-graph-width");
3425                         if (*arg == '=')
3426                                 graph_width = strtoul(arg + 1, &end, 10);
3427                         else if (!*arg && !av[1])
3428                                 die("Option '--stat-graph-width' requires a value");
3429                         else if (!*arg) {
3430                                 graph_width = strtoul(av[1], &end, 10);
3431                                 argcount = 2;
3432                         }
3433                 } else if (!prefixcmp(arg, "-count")) {
3434                         arg += strlen("-count");
3435                         if (*arg == '=')
3436                                 count = strtoul(arg + 1, &end, 10);
3437                         else if (!*arg && !av[1])
3438                                 die("Option '--stat-count' requires a value");
3439                         else if (!*arg) {
3440                                 count = strtoul(av[1], &end, 10);
3441                                 argcount = 2;
3442                         }
3443                 }
3444                 break;
3445         case '=':
3446                 width = strtoul(arg+1, &end, 10);
3447                 if (*end == ',')
3448                         name_width = strtoul(end+1, &end, 10);
3449                 if (*end == ',')
3450                         count = strtoul(end+1, &end, 10);
3451         }
3452
3453         /* Important! This checks all the error cases! */
3454         if (*end)
3455                 return 0;
3456         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3457         options->stat_name_width = name_width;
3458         options->stat_graph_width = graph_width;
3459         options->stat_width = width;
3460         options->stat_count = count;
3461         return argcount;
3462 }
3463
3464 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3465 {
3466         struct strbuf errmsg = STRBUF_INIT;
3467         if (parse_dirstat_params(options, params, &errmsg))
3468                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3469                     errmsg.buf);
3470         strbuf_release(&errmsg);
3471         /*
3472          * The caller knows a dirstat-related option is given from the command
3473          * line; allow it to say "return this_function();"
3474          */
3475         options->output_format |= DIFF_FORMAT_DIRSTAT;
3476         return 1;
3477 }
3478
3479 static int parse_submodule_opt(struct diff_options *options, const char *value)
3480 {
3481         if (parse_submodule_params(options, value))
3482                 die(_("Failed to parse --submodule option parameter: '%s'"),
3483                         value);
3484         return 1;
3485 }
3486
3487 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3488 {
3489         const char *arg = av[0];
3490         const char *optarg;
3491         int argcount;
3492
3493         /* Output format options */
3494         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3495                 options->output_format |= DIFF_FORMAT_PATCH;
3496         else if (opt_arg(arg, 'U', "unified", &options->context))
3497                 options->output_format |= DIFF_FORMAT_PATCH;
3498         else if (!strcmp(arg, "--raw"))
3499                 options->output_format |= DIFF_FORMAT_RAW;
3500         else if (!strcmp(arg, "--patch-with-raw"))
3501                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3502         else if (!strcmp(arg, "--numstat"))
3503                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3504         else if (!strcmp(arg, "--shortstat"))
3505                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3506         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3507                 return parse_dirstat_opt(options, "");
3508         else if (!prefixcmp(arg, "-X"))
3509                 return parse_dirstat_opt(options, arg + 2);
3510         else if (!prefixcmp(arg, "--dirstat="))
3511                 return parse_dirstat_opt(options, arg + 10);
3512         else if (!strcmp(arg, "--cumulative"))
3513                 return parse_dirstat_opt(options, "cumulative");
3514         else if (!strcmp(arg, "--dirstat-by-file"))
3515                 return parse_dirstat_opt(options, "files");
3516         else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3517                 parse_dirstat_opt(options, "files");
3518                 return parse_dirstat_opt(options, arg + 18);
3519         }
3520         else if (!strcmp(arg, "--check"))
3521                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3522         else if (!strcmp(arg, "--summary"))
3523                 options->output_format |= DIFF_FORMAT_SUMMARY;
3524         else if (!strcmp(arg, "--patch-with-stat"))
3525                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3526         else if (!strcmp(arg, "--name-only"))
3527                 options->output_format |= DIFF_FORMAT_NAME;
3528         else if (!strcmp(arg, "--name-status"))
3529                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3530         else if (!strcmp(arg, "-s"))
3531                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3532         else if (!prefixcmp(arg, "--stat"))
3533                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3534                 return stat_opt(options, av);
3535
3536         /* renames options */
3537         else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3538                  !strcmp(arg, "--break-rewrites")) {
3539                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3540                         return error("invalid argument to -B: %s", arg+2);
3541         }
3542         else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3543                  !strcmp(arg, "--find-renames")) {
3544                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3545                         return error("invalid argument to -M: %s", arg+2);
3546                 options->detect_rename = DIFF_DETECT_RENAME;
3547         }
3548         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3549                 options->irreversible_delete = 1;
3550         }
3551         else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3552                  !strcmp(arg, "--find-copies")) {
3553                 if (options->detect_rename == DIFF_DETECT_COPY)
3554                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3555                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3556                         return error("invalid argument to -C: %s", arg+2);
3557                 options->detect_rename = DIFF_DETECT_COPY;
3558         }
3559         else if (!strcmp(arg, "--no-renames"))
3560                 options->detect_rename = 0;
3561         else if (!strcmp(arg, "--rename-empty"))
3562                 DIFF_OPT_SET(options, RENAME_EMPTY);
3563         else if (!strcmp(arg, "--no-rename-empty"))
3564                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3565         else if (!strcmp(arg, "--relative"))
3566                 DIFF_OPT_SET(options, RELATIVE_NAME);
3567         else if (!prefixcmp(arg, "--relative=")) {
3568                 DIFF_OPT_SET(options, RELATIVE_NAME);
3569                 options->prefix = arg + 11;
3570         }
3571
3572         /* xdiff options */
3573         else if (!strcmp(arg, "--minimal"))
3574                 DIFF_XDL_SET(options, NEED_MINIMAL);
3575         else if (!strcmp(arg, "--no-minimal"))
3576                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3577         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3578                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3579         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3580                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3581         else if (!strcmp(arg, "--ignore-space-at-eol"))
3582                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3583         else if (!strcmp(arg, "--patience"))
3584                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3585         else if (!strcmp(arg, "--histogram"))
3586                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3587         else if (!prefixcmp(arg, "--diff-algorithm=")) {
3588                 long value = parse_algorithm_value(arg+17);
3589                 if (value < 0)
3590                         return error("option diff-algorithm accepts \"myers\", "
3591                                      "\"minimal\", \"patience\" and \"histogram\"");
3592                 /* clear out previous settings */
3593                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3594                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3595                 options->xdl_opts |= value;
3596         }
3597
3598         /* flags options */
3599         else if (!strcmp(arg, "--binary")) {
3600                 options->output_format |= DIFF_FORMAT_PATCH;
3601                 DIFF_OPT_SET(options, BINARY);
3602         }
3603         else if (!strcmp(arg, "--full-index"))
3604                 DIFF_OPT_SET(options, FULL_INDEX);
3605         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3606                 DIFF_OPT_SET(options, TEXT);
3607         else if (!strcmp(arg, "-R"))
3608                 DIFF_OPT_SET(options, REVERSE_DIFF);
3609         else if (!strcmp(arg, "--find-copies-harder"))
3610                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3611         else if (!strcmp(arg, "--follow"))
3612                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3613         else if (!strcmp(arg, "--no-follow"))
3614                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3615         else if (!strcmp(arg, "--color"))
3616                 options->use_color = 1;
3617         else if (!prefixcmp(arg, "--color=")) {
3618                 int value = git_config_colorbool(NULL, arg+8);
3619                 if (value < 0)
3620                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3621                 options->use_color = value;
3622         }
3623         else if (!strcmp(arg, "--no-color"))
3624                 options->use_color = 0;
3625         else if (!strcmp(arg, "--color-words")) {
3626                 options->use_color = 1;
3627                 options->word_diff = DIFF_WORDS_COLOR;
3628         }
3629         else if (!prefixcmp(arg, "--color-words=")) {
3630                 options->use_color = 1;
3631                 options->word_diff = DIFF_WORDS_COLOR;
3632                 options->word_regex = arg + 14;
3633         }
3634         else if (!strcmp(arg, "--word-diff")) {
3635                 if (options->word_diff == DIFF_WORDS_NONE)
3636                         options->word_diff = DIFF_WORDS_PLAIN;
3637         }
3638         else if (!prefixcmp(arg, "--word-diff=")) {
3639                 const char *type = arg + 12;
3640                 if (!strcmp(type, "plain"))
3641                         options->word_diff = DIFF_WORDS_PLAIN;
3642                 else if (!strcmp(type, "color")) {
3643                         options->use_color = 1;
3644                         options->word_diff = DIFF_WORDS_COLOR;
3645                 }
3646                 else if (!strcmp(type, "porcelain"))
3647                         options->word_diff = DIFF_WORDS_PORCELAIN;
3648                 else if (!strcmp(type, "none"))
3649                         options->word_diff = DIFF_WORDS_NONE;
3650                 else
3651                         die("bad --word-diff argument: %s", type);
3652         }
3653         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3654                 if (options->word_diff == DIFF_WORDS_NONE)
3655                         options->word_diff = DIFF_WORDS_PLAIN;
3656                 options->word_regex = optarg;
3657                 return argcount;
3658         }
3659         else if (!strcmp(arg, "--exit-code"))
3660                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3661         else if (!strcmp(arg, "--quiet"))
3662                 DIFF_OPT_SET(options, QUICK);
3663         else if (!strcmp(arg, "--ext-diff"))
3664                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3665         else if (!strcmp(arg, "--no-ext-diff"))
3666                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3667         else if (!strcmp(arg, "--textconv"))
3668                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3669         else if (!strcmp(arg, "--no-textconv"))
3670                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3671         else if (!strcmp(arg, "--ignore-submodules")) {
3672                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3673                 handle_ignore_submodules_arg(options, "all");
3674         } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3675                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3676                 handle_ignore_submodules_arg(options, arg + 20);
3677         } else if (!strcmp(arg, "--submodule"))
3678                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3679         else if (!prefixcmp(arg, "--submodule="))
3680                 return parse_submodule_opt(options, arg + 12);
3681
3682         /* misc options */
3683         else if (!strcmp(arg, "-z"))
3684                 options->line_termination = 0;
3685         else if ((argcount = short_opt('l', av, &optarg))) {
3686                 options->rename_limit = strtoul(optarg, NULL, 10);
3687                 return argcount;
3688         }
3689         else if ((argcount = short_opt('S', av, &optarg))) {
3690                 options->pickaxe = optarg;
3691                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3692                 return argcount;
3693         } else if ((argcount = short_opt('G', av, &optarg))) {
3694                 options->pickaxe = optarg;
3695                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3696                 return argcount;
3697         }
3698         else if (!strcmp(arg, "--pickaxe-all"))
3699                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3700         else if (!strcmp(arg, "--pickaxe-regex"))
3701                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3702         else if ((argcount = short_opt('O', av, &optarg))) {
3703                 options->orderfile = optarg;
3704                 return argcount;
3705         }
3706         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3707                 options->filter = optarg;
3708                 return argcount;
3709         }
3710         else if (!strcmp(arg, "--abbrev"))
3711                 options->abbrev = DEFAULT_ABBREV;
3712         else if (!prefixcmp(arg, "--abbrev=")) {
3713                 options->abbrev = strtoul(arg + 9, NULL, 10);
3714                 if (options->abbrev < MINIMUM_ABBREV)
3715                         options->abbrev = MINIMUM_ABBREV;
3716                 else if (40 < options->abbrev)
3717                         options->abbrev = 40;
3718         }
3719         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3720                 options->a_prefix = optarg;
3721                 return argcount;
3722         }
3723         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3724                 options->b_prefix = optarg;
3725                 return argcount;
3726         }
3727         else if (!strcmp(arg, "--no-prefix"))
3728                 options->a_prefix = options->b_prefix = "";
3729         else if (opt_arg(arg, '\0', "inter-hunk-context",
3730                          &options->interhunkcontext))
3731                 ;
3732         else if (!strcmp(arg, "-W"))
3733                 DIFF_OPT_SET(options, FUNCCONTEXT);
3734         else if (!strcmp(arg, "--function-context"))
3735                 DIFF_OPT_SET(options, FUNCCONTEXT);
3736         else if (!strcmp(arg, "--no-function-context"))
3737                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3738         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3739                 options->file = fopen(optarg, "w");
3740                 if (!options->file)
3741                         die_errno("Could not open '%s'", optarg);
3742                 options->close_file = 1;
3743                 return argcount;
3744         } else
3745                 return 0;
3746         return 1;
3747 }
3748
3749 int parse_rename_score(const char **cp_p)
3750 {
3751         unsigned long num, scale;
3752         int ch, dot;
3753         const char *cp = *cp_p;
3754
3755         num = 0;
3756         scale = 1;
3757         dot = 0;
3758         for (;;) {
3759                 ch = *cp;
3760                 if ( !dot && ch == '.' ) {
3761                         scale = 1;
3762                         dot = 1;
3763                 } else if ( ch == '%' ) {
3764                         scale = dot ? scale*100 : 100;
3765                         cp++;   /* % is always at the end */
3766                         break;
3767                 } else if ( ch >= '0' && ch <= '9' ) {
3768                         if ( scale < 100000 ) {
3769                                 scale *= 10;
3770                                 num = (num*10) + (ch-'0');
3771                         }
3772                 } else {
3773                         break;
3774                 }
3775                 cp++;
3776         }
3777         *cp_p = cp;
3778
3779         /* user says num divided by scale and we say internally that
3780          * is MAX_SCORE * num / scale.
3781          */
3782         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3783 }
3784
3785 static int diff_scoreopt_parse(const char *opt)
3786 {
3787         int opt1, opt2, cmd;
3788
3789         if (*opt++ != '-')
3790                 return -1;
3791         cmd = *opt++;
3792         if (cmd == '-') {
3793                 /* convert the long-form arguments into short-form versions */
3794                 if (!prefixcmp(opt, "break-rewrites")) {
3795                         opt += strlen("break-rewrites");
3796                         if (*opt == 0 || *opt++ == '=')
3797                                 cmd = 'B';
3798                 } else if (!prefixcmp(opt, "find-copies")) {
3799                         opt += strlen("find-copies");
3800                         if (*opt == 0 || *opt++ == '=')
3801                                 cmd = 'C';
3802                 } else if (!prefixcmp(opt, "find-renames")) {
3803                         opt += strlen("find-renames");
3804                         if (*opt == 0 || *opt++ == '=')
3805                                 cmd = 'M';
3806                 }
3807         }
3808         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3809                 return -1; /* that is not a -M, -C nor -B option */
3810
3811         opt1 = parse_rename_score(&opt);
3812         if (cmd != 'B')
3813                 opt2 = 0;
3814         else {
3815                 if (*opt == 0)
3816                         opt2 = 0;
3817                 else if (*opt != '/')
3818                         return -1; /* we expect -B80/99 or -B80 */
3819                 else {
3820                         opt++;
3821                         opt2 = parse_rename_score(&opt);
3822                 }
3823         }
3824         if (*opt != 0)
3825                 return -1;
3826         return opt1 | (opt2 << 16);
3827 }
3828
3829 struct diff_queue_struct diff_queued_diff;
3830
3831 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3832 {
3833         if (queue->alloc <= queue->nr) {
3834                 queue->alloc = alloc_nr(queue->alloc);
3835                 queue->queue = xrealloc(queue->queue,
3836                                         sizeof(dp) * queue->alloc);
3837         }
3838         queue->queue[queue->nr++] = dp;
3839 }
3840
3841 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3842                                  struct diff_filespec *one,
3843                                  struct diff_filespec *two)
3844 {
3845         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3846         dp->one = one;
3847         dp->two = two;
3848         if (queue)
3849                 diff_q(queue, dp);
3850         return dp;
3851 }
3852
3853 void diff_free_filepair(struct diff_filepair *p)
3854 {
3855         free_filespec(p->one);
3856         free_filespec(p->two);
3857         free(p);
3858 }
3859
3860 /* This is different from find_unique_abbrev() in that
3861  * it stuffs the result with dots for alignment.
3862  */
3863 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3864 {
3865         int abblen;
3866         const char *abbrev;
3867         if (len == 40)
3868                 return sha1_to_hex(sha1);
3869
3870         abbrev = find_unique_abbrev(sha1, len);
3871         abblen = strlen(abbrev);
3872         if (abblen < 37) {
3873                 static char hex[41];
3874                 if (len < abblen && abblen <= len + 2)
3875                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3876                 else
3877                         sprintf(hex, "%s...", abbrev);
3878                 return hex;
3879         }
3880         return sha1_to_hex(sha1);
3881 }
3882
3883 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3884 {
3885         int line_termination = opt->line_termination;
3886         int inter_name_termination = line_termination ? '\t' : '\0';
3887
3888         fprintf(opt->file, "%s", diff_line_prefix(opt));
3889         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3890                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3891                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
3892                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3893         }
3894         if (p->score) {
3895                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3896                         inter_name_termination);
3897         } else {
3898                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3899         }
3900
3901         if (p->status == DIFF_STATUS_COPIED ||
3902             p->status == DIFF_STATUS_RENAMED) {
3903                 const char *name_a, *name_b;
3904                 name_a = p->one->path;
3905                 name_b = p->two->path;
3906                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3907                 write_name_quoted(name_a, opt->file, inter_name_termination);
3908                 write_name_quoted(name_b, opt->file, line_termination);
3909         } else {
3910                 const char *name_a, *name_b;
3911                 name_a = p->one->mode ? p->one->path : p->two->path;
3912                 name_b = NULL;
3913                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3914                 write_name_quoted(name_a, opt->file, line_termination);
3915         }
3916 }
3917
3918 int diff_unmodified_pair(struct diff_filepair *p)
3919 {
3920         /* This function is written stricter than necessary to support
3921          * the currently implemented transformers, but the idea is to
3922          * let transformers to produce diff_filepairs any way they want,
3923          * and filter and clean them up here before producing the output.
3924          */
3925         struct diff_filespec *one = p->one, *two = p->two;
3926
3927         if (DIFF_PAIR_UNMERGED(p))
3928                 return 0; /* unmerged is interesting */
3929
3930         /* deletion, addition, mode or type change
3931          * and rename are all interesting.
3932          */
3933         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3934             DIFF_PAIR_MODE_CHANGED(p) ||
3935             strcmp(one->path, two->path))
3936                 return 0;
3937
3938         /* both are valid and point at the same path.  that is, we are
3939          * dealing with a change.
3940          */
3941         if (one->sha1_valid && two->sha1_valid &&
3942             !hashcmp(one->sha1, two->sha1) &&
3943             !one->dirty_submodule && !two->dirty_submodule)
3944                 return 1; /* no change */
3945         if (!one->sha1_valid && !two->sha1_valid)
3946                 return 1; /* both look at the same file on the filesystem. */
3947         return 0;
3948 }
3949
3950 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3951 {
3952         if (diff_unmodified_pair(p))
3953                 return;
3954
3955         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3956             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3957                 return; /* no tree diffs in patch format */
3958
3959         run_diff(p, o);
3960 }
3961
3962 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3963                             struct diffstat_t *diffstat)
3964 {
3965         if (diff_unmodified_pair(p))
3966                 return;
3967
3968         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3969             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3970                 return; /* no useful stat for tree diffs */
3971
3972         run_diffstat(p, o, diffstat);
3973 }
3974
3975 static void diff_flush_checkdiff(struct diff_filepair *p,
3976                 struct diff_options *o)
3977 {
3978         if (diff_unmodified_pair(p))
3979                 return;
3980
3981         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3982             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3983                 return; /* nothing to check in tree diffs */
3984
3985         run_checkdiff(p, o);
3986 }
3987
3988 int diff_queue_is_empty(void)
3989 {
3990         struct diff_queue_struct *q = &diff_queued_diff;
3991         int i;
3992         for (i = 0; i < q->nr; i++)
3993                 if (!diff_unmodified_pair(q->queue[i]))
3994                         return 0;
3995         return 1;
3996 }
3997
3998 #if DIFF_DEBUG
3999 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4000 {
4001         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4002                 x, one ? one : "",
4003                 s->path,
4004                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4005                 s->mode,
4006                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4007         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
4008                 x, one ? one : "",
4009                 s->size, s->xfrm_flags);
4010 }
4011
4012 void diff_debug_filepair(const struct diff_filepair *p, int i)
4013 {
4014         diff_debug_filespec(p->one, i, "one");
4015         diff_debug_filespec(p->two, i, "two");
4016         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4017                 p->score, p->status ? p->status : '?',
4018                 p->one->rename_used, p->broken_pair);
4019 }
4020
4021 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4022 {
4023         int i;
4024         if (msg)
4025                 fprintf(stderr, "%s\n", msg);
4026         fprintf(stderr, "q->nr = %d\n", q->nr);
4027         for (i = 0; i < q->nr; i++) {
4028                 struct diff_filepair *p = q->queue[i];
4029                 diff_debug_filepair(p, i);
4030         }
4031 }
4032 #endif
4033
4034 static void diff_resolve_rename_copy(void)
4035 {
4036         int i;
4037         struct diff_filepair *p;
4038         struct diff_queue_struct *q = &diff_queued_diff;
4039
4040         diff_debug_queue("resolve-rename-copy", q);
4041
4042         for (i = 0; i < q->nr; i++) {
4043                 p = q->queue[i];
4044                 p->status = 0; /* undecided */
4045                 if (DIFF_PAIR_UNMERGED(p))
4046                         p->status = DIFF_STATUS_UNMERGED;
4047                 else if (!DIFF_FILE_VALID(p->one))
4048                         p->status = DIFF_STATUS_ADDED;
4049                 else if (!DIFF_FILE_VALID(p->two))
4050                         p->status = DIFF_STATUS_DELETED;
4051                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4052                         p->status = DIFF_STATUS_TYPE_CHANGED;
4053
4054                 /* from this point on, we are dealing with a pair
4055                  * whose both sides are valid and of the same type, i.e.
4056                  * either in-place edit or rename/copy edit.
4057                  */
4058                 else if (DIFF_PAIR_RENAME(p)) {
4059                         /*
4060                          * A rename might have re-connected a broken
4061                          * pair up, causing the pathnames to be the
4062                          * same again. If so, that's not a rename at
4063                          * all, just a modification..
4064                          *
4065                          * Otherwise, see if this source was used for
4066                          * multiple renames, in which case we decrement
4067                          * the count, and call it a copy.
4068                          */
4069                         if (!strcmp(p->one->path, p->two->path))
4070                                 p->status = DIFF_STATUS_MODIFIED;
4071                         else if (--p->one->rename_used > 0)
4072                                 p->status = DIFF_STATUS_COPIED;
4073                         else
4074                                 p->status = DIFF_STATUS_RENAMED;
4075                 }
4076                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
4077                          p->one->mode != p->two->mode ||
4078                          p->one->dirty_submodule ||
4079                          p->two->dirty_submodule ||
4080                          is_null_sha1(p->one->sha1))
4081                         p->status = DIFF_STATUS_MODIFIED;
4082                 else {
4083                         /* This is a "no-change" entry and should not
4084                          * happen anymore, but prepare for broken callers.
4085                          */
4086                         error("feeding unmodified %s to diffcore",
4087                               p->one->path);
4088                         p->status = DIFF_STATUS_UNKNOWN;
4089                 }
4090         }
4091         diff_debug_queue("resolve-rename-copy done", q);
4092 }
4093
4094 static int check_pair_status(struct diff_filepair *p)
4095 {
4096         switch (p->status) {
4097         case DIFF_STATUS_UNKNOWN:
4098                 return 0;
4099         case 0:
4100                 die("internal error in diff-resolve-rename-copy");
4101         default:
4102                 return 1;
4103         }
4104 }
4105
4106 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4107 {
4108         int fmt = opt->output_format;
4109
4110         if (fmt & DIFF_FORMAT_CHECKDIFF)
4111                 diff_flush_checkdiff(p, opt);
4112         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4113                 diff_flush_raw(p, opt);
4114         else if (fmt & DIFF_FORMAT_NAME) {
4115                 const char *name_a, *name_b;
4116                 name_a = p->two->path;
4117                 name_b = NULL;
4118                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4119                 write_name_quoted(name_a, opt->file, opt->line_termination);
4120         }
4121 }
4122
4123 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4124 {
4125         if (fs->mode)
4126                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4127         else
4128                 fprintf(file, " %s ", newdelete);
4129         write_name_quoted(fs->path, file, '\n');
4130 }
4131
4132
4133 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4134                 const char *line_prefix)
4135 {
4136         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4137                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4138                         p->two->mode, show_name ? ' ' : '\n');
4139                 if (show_name) {
4140                         write_name_quoted(p->two->path, file, '\n');
4141                 }
4142         }
4143 }
4144
4145 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4146                         const char *line_prefix)
4147 {
4148         char *names = pprint_rename(p->one->path, p->two->path);
4149
4150         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4151         free(names);
4152         show_mode_change(file, p, 0, line_prefix);
4153 }
4154
4155 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4156 {
4157         FILE *file = opt->file;
4158         const char *line_prefix = diff_line_prefix(opt);
4159
4160         switch(p->status) {
4161         case DIFF_STATUS_DELETED:
4162                 fputs(line_prefix, file);
4163                 show_file_mode_name(file, "delete", p->one);
4164                 break;
4165         case DIFF_STATUS_ADDED:
4166                 fputs(line_prefix, file);
4167                 show_file_mode_name(file, "create", p->two);
4168                 break;
4169         case DIFF_STATUS_COPIED:
4170                 fputs(line_prefix, file);
4171                 show_rename_copy(file, "copy", p, line_prefix);
4172                 break;
4173         case DIFF_STATUS_RENAMED:
4174                 fputs(line_prefix, file);
4175                 show_rename_copy(file, "rename", p, line_prefix);
4176                 break;
4177         default:
4178                 if (p->score) {
4179                         fprintf(file, "%s rewrite ", line_prefix);
4180                         write_name_quoted(p->two->path, file, ' ');
4181                         fprintf(file, "(%d%%)\n", similarity_index(p));
4182                 }
4183                 show_mode_change(file, p, !p->score, line_prefix);
4184                 break;
4185         }
4186 }
4187
4188 struct patch_id_t {
4189         git_SHA_CTX *ctx;
4190         int patchlen;
4191 };
4192
4193 static int remove_space(char *line, int len)
4194 {
4195         int i;
4196         char *dst = line;
4197         unsigned char c;
4198
4199         for (i = 0; i < len; i++)
4200                 if (!isspace((c = line[i])))
4201                         *dst++ = c;
4202
4203         return dst - line;
4204 }
4205
4206 static void patch_id_consume(void *priv, char *line, unsigned long len)
4207 {
4208         struct patch_id_t *data = priv;
4209         int new_len;
4210
4211         /* Ignore line numbers when computing the SHA1 of the patch */
4212         if (!prefixcmp(line, "@@ -"))
4213                 return;
4214
4215         new_len = remove_space(line, len);
4216
4217         git_SHA1_Update(data->ctx, line, new_len);
4218         data->patchlen += new_len;
4219 }
4220
4221 /* returns 0 upon success, and writes result into sha1 */
4222 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4223 {
4224         struct diff_queue_struct *q = &diff_queued_diff;
4225         int i;
4226         git_SHA_CTX ctx;
4227         struct patch_id_t data;
4228         char buffer[PATH_MAX * 4 + 20];
4229
4230         git_SHA1_Init(&ctx);
4231         memset(&data, 0, sizeof(struct patch_id_t));
4232         data.ctx = &ctx;
4233
4234         for (i = 0; i < q->nr; i++) {
4235                 xpparam_t xpp;
4236                 xdemitconf_t xecfg;
4237                 mmfile_t mf1, mf2;
4238                 struct diff_filepair *p = q->queue[i];
4239                 int len1, len2;
4240
4241                 memset(&xpp, 0, sizeof(xpp));
4242                 memset(&xecfg, 0, sizeof(xecfg));
4243                 if (p->status == 0)
4244                         return error("internal diff status error");
4245                 if (p->status == DIFF_STATUS_UNKNOWN)
4246                         continue;
4247                 if (diff_unmodified_pair(p))
4248                         continue;
4249                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4250                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4251                         continue;
4252                 if (DIFF_PAIR_UNMERGED(p))
4253                         continue;
4254
4255                 diff_fill_sha1_info(p->one);
4256                 diff_fill_sha1_info(p->two);
4257                 if (fill_mmfile(&mf1, p->one) < 0 ||
4258                                 fill_mmfile(&mf2, p->two) < 0)
4259                         return error("unable to read files to diff");
4260
4261                 len1 = remove_space(p->one->path, strlen(p->one->path));
4262                 len2 = remove_space(p->two->path, strlen(p->two->path));
4263                 if (p->one->mode == 0)
4264                         len1 = snprintf(buffer, sizeof(buffer),
4265                                         "diff--gita/%.*sb/%.*s"
4266                                         "newfilemode%06o"
4267                                         "---/dev/null"
4268                                         "+++b/%.*s",
4269                                         len1, p->one->path,
4270                                         len2, p->two->path,
4271                                         p->two->mode,
4272                                         len2, p->two->path);
4273                 else if (p->two->mode == 0)
4274                         len1 = snprintf(buffer, sizeof(buffer),
4275                                         "diff--gita/%.*sb/%.*s"
4276                                         "deletedfilemode%06o"
4277                                         "---a/%.*s"
4278                                         "+++/dev/null",
4279                                         len1, p->one->path,
4280                                         len2, p->two->path,
4281                                         p->one->mode,
4282                                         len1, p->one->path);
4283                 else
4284                         len1 = snprintf(buffer, sizeof(buffer),
4285                                         "diff--gita/%.*sb/%.*s"
4286                                         "---a/%.*s"
4287                                         "+++b/%.*s",
4288                                         len1, p->one->path,
4289                                         len2, p->two->path,
4290                                         len1, p->one->path,
4291                                         len2, p->two->path);
4292                 git_SHA1_Update(&ctx, buffer, len1);
4293
4294                 if (diff_filespec_is_binary(p->one) ||
4295                     diff_filespec_is_binary(p->two)) {
4296                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4297                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4298                         continue;
4299                 }
4300
4301                 xpp.flags = 0;
4302                 xecfg.ctxlen = 3;
4303                 xecfg.flags = 0;
4304                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4305                               &xpp, &xecfg);
4306         }
4307
4308         git_SHA1_Final(sha1, &ctx);
4309         return 0;
4310 }
4311
4312 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4313 {
4314         struct diff_queue_struct *q = &diff_queued_diff;
4315         int i;
4316         int result = diff_get_patch_id(options, sha1);
4317
4318         for (i = 0; i < q->nr; i++)
4319                 diff_free_filepair(q->queue[i]);
4320
4321         free(q->queue);
4322         DIFF_QUEUE_CLEAR(q);
4323
4324         return result;
4325 }
4326
4327 static int is_summary_empty(const struct diff_queue_struct *q)
4328 {
4329         int i;
4330
4331         for (i = 0; i < q->nr; i++) {
4332                 const struct diff_filepair *p = q->queue[i];
4333
4334                 switch (p->status) {
4335                 case DIFF_STATUS_DELETED:
4336                 case DIFF_STATUS_ADDED:
4337                 case DIFF_STATUS_COPIED:
4338                 case DIFF_STATUS_RENAMED:
4339                         return 0;
4340                 default:
4341                         if (p->score)
4342                                 return 0;
4343                         if (p->one->mode && p->two->mode &&
4344                             p->one->mode != p->two->mode)
4345                                 return 0;
4346                         break;
4347                 }
4348         }
4349         return 1;
4350 }
4351
4352 static const char rename_limit_warning[] =
4353 "inexact rename detection was skipped due to too many files.";
4354
4355 static const char degrade_cc_to_c_warning[] =
4356 "only found copies from modified paths due to too many files.";
4357
4358 static const char rename_limit_advice[] =
4359 "you may want to set your %s variable to at least "
4360 "%d and retry the command.";
4361
4362 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4363 {
4364         if (degraded_cc)
4365                 warning(degrade_cc_to_c_warning);
4366         else if (needed)
4367                 warning(rename_limit_warning);
4368         else
4369                 return;
4370         if (0 < needed && needed < 32767)
4371                 warning(rename_limit_advice, varname, needed);
4372 }
4373
4374 void diff_flush(struct diff_options *options)
4375 {
4376         struct diff_queue_struct *q = &diff_queued_diff;
4377         int i, output_format = options->output_format;
4378         int separator = 0;
4379         int dirstat_by_line = 0;
4380
4381         /*
4382          * Order: raw, stat, summary, patch
4383          * or:    name/name-status/checkdiff (other bits clear)
4384          */
4385         if (!q->nr)
4386                 goto free_queue;
4387
4388         if (output_format & (DIFF_FORMAT_RAW |
4389                              DIFF_FORMAT_NAME |
4390                              DIFF_FORMAT_NAME_STATUS |
4391                              DIFF_FORMAT_CHECKDIFF)) {
4392                 for (i = 0; i < q->nr; i++) {
4393                         struct diff_filepair *p = q->queue[i];
4394                         if (check_pair_status(p))
4395                                 flush_one_pair(p, options);
4396                 }
4397                 separator++;
4398         }
4399
4400         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4401                 dirstat_by_line = 1;
4402
4403         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4404             dirstat_by_line) {
4405                 struct diffstat_t diffstat;
4406
4407                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4408                 for (i = 0; i < q->nr; i++) {
4409                         struct diff_filepair *p = q->queue[i];
4410                         if (check_pair_status(p))
4411                                 diff_flush_stat(p, options, &diffstat);
4412                 }
4413                 if (output_format & DIFF_FORMAT_NUMSTAT)
4414                         show_numstat(&diffstat, options);
4415                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4416                         show_stats(&diffstat, options);
4417                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4418                         show_shortstats(&diffstat, options);
4419                 if (output_format & DIFF_FORMAT_DIRSTAT)
4420                         show_dirstat_by_line(&diffstat, options);
4421                 free_diffstat_info(&diffstat);
4422                 separator++;
4423         }
4424         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4425                 show_dirstat(options);
4426
4427         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4428                 for (i = 0; i < q->nr; i++) {
4429                         diff_summary(options, q->queue[i]);
4430                 }
4431                 separator++;
4432         }
4433
4434         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4435             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4436             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4437                 /*
4438                  * run diff_flush_patch for the exit status. setting
4439                  * options->file to /dev/null should be safe, becaue we
4440                  * aren't supposed to produce any output anyway.
4441                  */
4442                 if (options->close_file)
4443                         fclose(options->file);
4444                 options->file = fopen("/dev/null", "w");
4445                 if (!options->file)
4446                         die_errno("Could not open /dev/null");
4447                 options->close_file = 1;
4448                 for (i = 0; i < q->nr; i++) {
4449                         struct diff_filepair *p = q->queue[i];
4450                         if (check_pair_status(p))
4451                                 diff_flush_patch(p, options);
4452                         if (options->found_changes)
4453                                 break;
4454                 }
4455         }
4456
4457         if (output_format & DIFF_FORMAT_PATCH) {
4458                 if (separator) {
4459                         fprintf(options->file, "%s%c",
4460                                 diff_line_prefix(options),
4461                                 options->line_termination);
4462                         if (options->stat_sep) {
4463                                 /* attach patch instead of inline */
4464                                 fputs(options->stat_sep, options->file);
4465                         }
4466                 }
4467
4468                 for (i = 0; i < q->nr; i++) {
4469                         struct diff_filepair *p = q->queue[i];
4470                         if (check_pair_status(p))
4471                                 diff_flush_patch(p, options);
4472                 }
4473         }
4474
4475         if (output_format & DIFF_FORMAT_CALLBACK)
4476                 options->format_callback(q, options, options->format_callback_data);
4477
4478         for (i = 0; i < q->nr; i++)
4479                 diff_free_filepair(q->queue[i]);
4480 free_queue:
4481         free(q->queue);
4482         DIFF_QUEUE_CLEAR(q);
4483         if (options->close_file)
4484                 fclose(options->file);
4485
4486         /*
4487          * Report the content-level differences with HAS_CHANGES;
4488          * diff_addremove/diff_change does not set the bit when
4489          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4490          */
4491         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4492                 if (options->found_changes)
4493                         DIFF_OPT_SET(options, HAS_CHANGES);
4494                 else
4495                         DIFF_OPT_CLR(options, HAS_CHANGES);
4496         }
4497 }
4498
4499 static void diffcore_apply_filter(const char *filter)
4500 {
4501         int i;
4502         struct diff_queue_struct *q = &diff_queued_diff;
4503         struct diff_queue_struct outq;
4504         DIFF_QUEUE_CLEAR(&outq);
4505
4506         if (!filter)
4507                 return;
4508
4509         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4510                 int found;
4511                 for (i = found = 0; !found && i < q->nr; i++) {
4512                         struct diff_filepair *p = q->queue[i];
4513                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4514                              ((p->score &&
4515                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4516                               (!p->score &&
4517                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4518                             ((p->status != DIFF_STATUS_MODIFIED) &&
4519                              strchr(filter, p->status)))
4520                                 found++;
4521                 }
4522                 if (found)
4523                         return;
4524
4525                 /* otherwise we will clear the whole queue
4526                  * by copying the empty outq at the end of this
4527                  * function, but first clear the current entries
4528                  * in the queue.
4529                  */
4530                 for (i = 0; i < q->nr; i++)
4531                         diff_free_filepair(q->queue[i]);
4532         }
4533         else {
4534                 /* Only the matching ones */
4535                 for (i = 0; i < q->nr; i++) {
4536                         struct diff_filepair *p = q->queue[i];
4537
4538                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4539                              ((p->score &&
4540                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4541                               (!p->score &&
4542                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4543                             ((p->status != DIFF_STATUS_MODIFIED) &&
4544                              strchr(filter, p->status)))
4545                                 diff_q(&outq, p);
4546                         else
4547                                 diff_free_filepair(p);
4548                 }
4549         }
4550         free(q->queue);
4551         *q = outq;
4552 }
4553
4554 /* Check whether two filespecs with the same mode and size are identical */
4555 static int diff_filespec_is_identical(struct diff_filespec *one,
4556                                       struct diff_filespec *two)
4557 {
4558         if (S_ISGITLINK(one->mode))
4559                 return 0;
4560         if (diff_populate_filespec(one, 0))
4561                 return 0;
4562         if (diff_populate_filespec(two, 0))
4563                 return 0;
4564         return !memcmp(one->data, two->data, one->size);
4565 }
4566
4567 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4568 {
4569         int i;
4570         struct diff_queue_struct *q = &diff_queued_diff;
4571         struct diff_queue_struct outq;
4572         DIFF_QUEUE_CLEAR(&outq);
4573
4574         for (i = 0; i < q->nr; i++) {
4575                 struct diff_filepair *p = q->queue[i];
4576
4577                 /*
4578                  * 1. Entries that come from stat info dirtiness
4579                  *    always have both sides (iow, not create/delete),
4580                  *    one side of the object name is unknown, with
4581                  *    the same mode and size.  Keep the ones that
4582                  *    do not match these criteria.  They have real
4583                  *    differences.
4584                  *
4585                  * 2. At this point, the file is known to be modified,
4586                  *    with the same mode and size, and the object
4587                  *    name of one side is unknown.  Need to inspect
4588                  *    the identical contents.
4589                  */
4590                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
4591                     !DIFF_FILE_VALID(p->two) ||
4592                     (p->one->sha1_valid && p->two->sha1_valid) ||
4593                     (p->one->mode != p->two->mode) ||
4594                     diff_populate_filespec(p->one, 1) ||
4595                     diff_populate_filespec(p->two, 1) ||
4596                     (p->one->size != p->two->size) ||
4597                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4598                         diff_q(&outq, p);
4599                 else {
4600                         /*
4601                          * The caller can subtract 1 from skip_stat_unmatch
4602                          * to determine how many paths were dirty only
4603                          * due to stat info mismatch.
4604                          */
4605                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4606                                 diffopt->skip_stat_unmatch++;
4607                         diff_free_filepair(p);
4608                 }
4609         }
4610         free(q->queue);
4611         *q = outq;
4612 }
4613
4614 static int diffnamecmp(const void *a_, const void *b_)
4615 {
4616         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4617         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4618         const char *name_a, *name_b;
4619
4620         name_a = a->one ? a->one->path : a->two->path;
4621         name_b = b->one ? b->one->path : b->two->path;
4622         return strcmp(name_a, name_b);
4623 }
4624
4625 void diffcore_fix_diff_index(struct diff_options *options)
4626 {
4627         struct diff_queue_struct *q = &diff_queued_diff;
4628         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4629 }
4630
4631 void diffcore_std(struct diff_options *options)
4632 {
4633         if (options->skip_stat_unmatch)
4634                 diffcore_skip_stat_unmatch(options);
4635         if (!options->found_follow) {
4636                 /* See try_to_follow_renames() in tree-diff.c */
4637                 if (options->break_opt != -1)
4638                         diffcore_break(options->break_opt);
4639                 if (options->detect_rename)
4640                         diffcore_rename(options);
4641                 if (options->break_opt != -1)
4642                         diffcore_merge_broken();
4643         }
4644         if (options->pickaxe)
4645                 diffcore_pickaxe(options);
4646         if (options->orderfile)
4647                 diffcore_order(options->orderfile);
4648         if (!options->found_follow)
4649                 /* See try_to_follow_renames() in tree-diff.c */
4650                 diff_resolve_rename_copy();
4651         diffcore_apply_filter(options->filter);
4652
4653         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4654                 DIFF_OPT_SET(options, HAS_CHANGES);
4655         else
4656                 DIFF_OPT_CLR(options, HAS_CHANGES);
4657
4658         options->found_follow = 0;
4659 }
4660
4661 int diff_result_code(struct diff_options *opt, int status)
4662 {
4663         int result = 0;
4664
4665         diff_warn_rename_limit("diff.renamelimit",
4666                                opt->needed_rename_limit,
4667                                opt->degraded_cc_to_c);
4668         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4669             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4670                 return status;
4671         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4672             DIFF_OPT_TST(opt, HAS_CHANGES))
4673                 result |= 01;
4674         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4675             DIFF_OPT_TST(opt, CHECK_FAILED))
4676                 result |= 02;
4677         return result;
4678 }
4679
4680 int diff_can_quit_early(struct diff_options *opt)
4681 {
4682         return (DIFF_OPT_TST(opt, QUICK) &&
4683                 !opt->filter &&
4684                 DIFF_OPT_TST(opt, HAS_CHANGES));
4685 }
4686
4687 /*
4688  * Shall changes to this submodule be ignored?
4689  *
4690  * Submodule changes can be configured to be ignored separately for each path,
4691  * but that configuration can be overridden from the command line.
4692  */
4693 static int is_submodule_ignored(const char *path, struct diff_options *options)
4694 {
4695         int ignored = 0;
4696         unsigned orig_flags = options->flags;
4697         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4698                 set_diffopt_flags_from_submodule_config(options, path);
4699         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4700                 ignored = 1;
4701         options->flags = orig_flags;
4702         return ignored;
4703 }
4704
4705 void diff_addremove(struct diff_options *options,
4706                     int addremove, unsigned mode,
4707                     const unsigned char *sha1,
4708                     int sha1_valid,
4709                     const char *concatpath, unsigned dirty_submodule)
4710 {
4711         struct diff_filespec *one, *two;
4712
4713         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4714                 return;
4715
4716         /* This may look odd, but it is a preparation for
4717          * feeding "there are unchanged files which should
4718          * not produce diffs, but when you are doing copy
4719          * detection you would need them, so here they are"
4720          * entries to the diff-core.  They will be prefixed
4721          * with something like '=' or '*' (I haven't decided
4722          * which but should not make any difference).
4723          * Feeding the same new and old to diff_change()
4724          * also has the same effect.
4725          * Before the final output happens, they are pruned after
4726          * merged into rename/copy pairs as appropriate.
4727          */
4728         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4729                 addremove = (addremove == '+' ? '-' :
4730                              addremove == '-' ? '+' : addremove);
4731
4732         if (options->prefix &&
4733             strncmp(concatpath, options->prefix, options->prefix_length))
4734                 return;
4735
4736         one = alloc_filespec(concatpath);
4737         two = alloc_filespec(concatpath);
4738
4739         if (addremove != '+')
4740                 fill_filespec(one, sha1, sha1_valid, mode);
4741         if (addremove != '-') {
4742                 fill_filespec(two, sha1, sha1_valid, mode);
4743                 two->dirty_submodule = dirty_submodule;
4744         }
4745
4746         diff_queue(&diff_queued_diff, one, two);
4747         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4748                 DIFF_OPT_SET(options, HAS_CHANGES);
4749 }
4750
4751 void diff_change(struct diff_options *options,
4752                  unsigned old_mode, unsigned new_mode,
4753                  const unsigned char *old_sha1,
4754                  const unsigned char *new_sha1,
4755                  int old_sha1_valid, int new_sha1_valid,
4756                  const char *concatpath,
4757                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4758 {
4759         struct diff_filespec *one, *two;
4760
4761         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4762             is_submodule_ignored(concatpath, options))
4763                 return;
4764
4765         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4766                 unsigned tmp;
4767                 const unsigned char *tmp_c;
4768                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4769                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4770                 tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4771                         new_sha1_valid = tmp;
4772                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4773                         new_dirty_submodule = tmp;
4774         }
4775
4776         if (options->prefix &&
4777             strncmp(concatpath, options->prefix, options->prefix_length))
4778                 return;
4779
4780         one = alloc_filespec(concatpath);
4781         two = alloc_filespec(concatpath);
4782         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4783         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4784         one->dirty_submodule = old_dirty_submodule;
4785         two->dirty_submodule = new_dirty_submodule;
4786
4787         diff_queue(&diff_queued_diff, one, two);
4788         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4789                 DIFF_OPT_SET(options, HAS_CHANGES);
4790 }
4791
4792 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4793 {
4794         struct diff_filepair *pair;
4795         struct diff_filespec *one, *two;
4796
4797         if (options->prefix &&
4798             strncmp(path, options->prefix, options->prefix_length))
4799                 return NULL;
4800
4801         one = alloc_filespec(path);
4802         two = alloc_filespec(path);
4803         pair = diff_queue(&diff_queued_diff, one, two);
4804         pair->is_unmerged = 1;
4805         return pair;
4806 }
4807
4808 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4809                 size_t *outsize)
4810 {
4811         struct diff_tempfile *temp;
4812         const char *argv[3];
4813         const char **arg = argv;
4814         struct child_process child;
4815         struct strbuf buf = STRBUF_INIT;
4816         int err = 0;
4817
4818         temp = prepare_temp_file(spec->path, spec);
4819         *arg++ = pgm;
4820         *arg++ = temp->name;
4821         *arg = NULL;
4822
4823         memset(&child, 0, sizeof(child));
4824         child.use_shell = 1;
4825         child.argv = argv;
4826         child.out = -1;
4827         if (start_command(&child)) {
4828                 remove_tempfile();
4829                 return NULL;
4830         }
4831
4832         if (strbuf_read(&buf, child.out, 0) < 0)
4833                 err = error("error reading from textconv command '%s'", pgm);
4834         close(child.out);
4835
4836         if (finish_command(&child) || err) {
4837                 strbuf_release(&buf);
4838                 remove_tempfile();
4839                 return NULL;
4840         }
4841         remove_tempfile();
4842
4843         return strbuf_detach(&buf, outsize);
4844 }
4845
4846 size_t fill_textconv(struct userdiff_driver *driver,
4847                      struct diff_filespec *df,
4848                      char **outbuf)
4849 {
4850         size_t size;
4851
4852         if (!driver || !driver->textconv) {
4853                 if (!DIFF_FILE_VALID(df)) {
4854                         *outbuf = "";
4855                         return 0;
4856                 }
4857                 if (diff_populate_filespec(df, 0))
4858                         die("unable to read files to diff");
4859                 *outbuf = df->data;
4860                 return df->size;
4861         }
4862
4863         if (driver->textconv_cache && df->sha1_valid) {
4864                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4865                                           &size);
4866                 if (*outbuf)
4867                         return size;
4868         }
4869
4870         *outbuf = run_textconv(driver->textconv, df, &size);
4871         if (!*outbuf)
4872                 die("unable to read files to diff");
4873
4874         if (driver->textconv_cache && df->sha1_valid) {
4875                 /* ignore errors, as we might be in a readonly repository */
4876                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4877                                 size);
4878                 /*
4879                  * we could save up changes and flush them all at the end,
4880                  * but we would need an extra call after all diffing is done.
4881                  * Since generating a cache entry is the slow path anyway,
4882                  * this extra overhead probably isn't a big deal.
4883                  */
4884                 notes_cache_write(driver->textconv_cache);
4885         }
4886
4887         return size;
4888 }
4889
4890 void setup_diff_pager(struct diff_options *opt)
4891 {
4892         /*
4893          * If the user asked for our exit code, then either they want --quiet
4894          * or --exit-code. We should definitely not bother with a pager in the
4895          * former case, as we will generate no output. Since we still properly
4896          * report our exit code even when a pager is run, we _could_ run a
4897          * pager with --exit-code. But since we have not done so historically,
4898          * and because it is easy to find people oneline advising "git diff
4899          * --exit-code" in hooks and other scripts, we do not do so.
4900          */
4901         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4902             check_pager_config("diff") != 0)
4903                 setup_pager();
4904 }