diff-lib.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "commit.h"
   7 #include "diff.h"
   8 #include "diffcore.h"
   9 #include "revision.h"
  10 #include "cache-tree.h"
  11 #include "path-list.h"
  12 #include "unpack-trees.h"
  13
  14 /*
  15  * diff-files
  16  */
  17
  18 static int read_directory(const char *path, struct path_list *list)
  19 {
  20         DIR *dir;
  21         struct dirent *e;
  22
  23         if (!(dir = opendir(path)))
  24                 return error("Could not open directory %s", path);
  25
  26         while ((e = readdir(dir)))
  27                 if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
  28                         path_list_insert(e->d_name, list);
  29
  30         closedir(dir);
  31         return 0;
  32 }
  33
  34 static int get_mode(const char *path, int *mode)
  35 {
  36         struct stat st;
  37
  38         if (!path || !strcmp(path, "/dev/null"))
  39                 *mode = 0;
  40         else if (!strcmp(path, "-"))
  41                 *mode = create_ce_mode(0666);
  42         else if (stat(path, &st))
  43                 return error("Could not access '%s'", path);
  44         else
  45                 *mode = st.st_mode;
  46         return 0;
  47 }
  48
  49 static int queue_diff(struct diff_options *o,
  50                 const char *name1, const char *name2)
  51 {
  52         int mode1 = 0, mode2 = 0;
  53
  54         if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
  55                 return -1;
  56
  57         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
  58                 return error("file/directory conflict: %s, %s", name1, name2);
  59
  60         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
  61                 char buffer1[PATH_MAX], buffer2[PATH_MAX];
  62                 struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
  63                 int len1 = 0, len2 = 0, i1, i2, ret = 0;
  64
  65                 if (name1 && read_directory(name1, &p1))
  66                         return -1;
  67                 if (name2 && read_directory(name2, &p2)) {
  68                         path_list_clear(&p1, 0);
  69                         return -1;
  70                 }
  71
  72                 if (name1) {
  73                         len1 = strlen(name1);
  74                         if (len1 > 0 && name1[len1 - 1] == '/')
  75                                 len1--;
  76                         memcpy(buffer1, name1, len1);
  77                         buffer1[len1++] = '/';
  78                 }
  79
  80                 if (name2) {
  81                         len2 = strlen(name2);
  82                         if (len2 > 0 && name2[len2 - 1] == '/')
  83                                 len2--;
  84                         memcpy(buffer2, name2, len2);
  85                         buffer2[len2++] = '/';
  86                 }
  87
  88                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
  89                         const char *n1, *n2;
  90                         int comp;
  91
  92                         if (i1 == p1.nr)
  93                                 comp = 1;
  94                         else if (i2 == p2.nr)
  95                                 comp = -1;
  96                         else
  97                                 comp = strcmp(p1.items[i1].path,
  98                                         p2.items[i2].path);
  99
 100                         if (comp > 0)
 101                                 n1 = NULL;
 102                         else {
 103                                 n1 = buffer1;
 104                                 strncpy(buffer1 + len1, p1.items[i1++].path,
 105                                                 PATH_MAX - len1);
 106                         }
 107
 108                         if (comp < 0)
 109                                 n2 = NULL;
 110                         else {
 111                                 n2 = buffer2;
 112                                 strncpy(buffer2 + len2, p2.items[i2++].path,
 113                                                 PATH_MAX - len2);
 114                         }
 115
 116                         ret = queue_diff(o, n1, n2);
 117                 }
 118                 path_list_clear(&p1, 0);
 119                 path_list_clear(&p2, 0);
 120
 121                 return ret;
 122         } else {
 123                 struct diff_filespec *d1, *d2;
 124
 125                 if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 126                         unsigned tmp;
 127                         const char *tmp_c;
 128                         tmp = mode1; mode1 = mode2; mode2 = tmp;
 129                         tmp_c = name1; name1 = name2; name2 = tmp_c;
 130                 }
 131
 132                 if (!name1)
 133                         name1 = "/dev/null";
 134                 if (!name2)
 135                         name2 = "/dev/null";
 136                 d1 = alloc_filespec(name1);
 137                 d2 = alloc_filespec(name2);
 138                 fill_filespec(d1, null_sha1, mode1);
 139                 fill_filespec(d2, null_sha1, mode2);
 140
 141                 diff_queue(&diff_queued_diff, d1, d2);
 142                 return 0;
 143         }
 144 }
 145
 146 /*
 147  * Does the path name a blob in the working tree, or a directory
 148  * in the working tree?
 149  */
 150 static int is_in_index(const char *path)
 151 {
 152         int len, pos;
 153         struct cache_entry *ce;
 154
 155         len = strlen(path);
 156         while (path[len-1] == '/')
 157                 len--;
 158         if (!len)
 159                 return 1; /* "." */
 160         pos = cache_name_pos(path, len);
 161         if (0 <= pos)
 162                 return 1;
 163         pos = -1 - pos;
 164         while (pos < active_nr) {
 165                 ce = active_cache[pos++];
 166                 if (ce_namelen(ce) <= len ||
 167                     strncmp(ce->name, path, len) ||
 168                     (ce->name[len] > '/'))
 169                         break; /* path cannot be a prefix */
 170                 if (ce->name[len] == '/')
 171                         return 1;
 172         }
 173         return 0;
 174 }
 175
 176 static int handle_diff_files_args(struct rev_info *revs,
 177                                   int argc, const char **argv,
 178                                   unsigned int *options)
 179 {
 180         *options = 0;
 181
 182         /* revs->max_count == -2 means --no-index */
 183         while (1 < argc && argv[1][0] == '-') {
 184                 if (!strcmp(argv[1], "--base"))
 185                         revs->max_count = 1;
 186                 else if (!strcmp(argv[1], "--ours"))
 187                         revs->max_count = 2;
 188                 else if (!strcmp(argv[1], "--theirs"))
 189                         revs->max_count = 3;
 190                 else if (!strcmp(argv[1], "-n") ||
 191                                 !strcmp(argv[1], "--no-index")) {
 192                         revs->max_count = -2;
 193                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
 194                         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 195                 }
 196                 else if (!strcmp(argv[1], "-q"))
 197                         *options |= DIFF_SILENT_ON_REMOVED;
 198                 else
 199                         return error("invalid option: %s", argv[1]);
 200                 argv++; argc--;
 201         }
 202
 203         if (revs->max_count == -1 && revs->diffopt.nr_paths == 2) {
 204                 /*
 205                  * If two files are specified, and at least one is untracked,
 206                  * default to no-index.
 207                  */
 208                 read_cache();
 209                 if (!is_in_index(revs->diffopt.paths[0]) ||
 210                                         !is_in_index(revs->diffopt.paths[1])) {
 211                         revs->max_count = -2;
 212                         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 213                 }
 214         }
 215
 216         /*
 217          * Make sure there are NO revision (i.e. pending object) parameter,
 218          * rev.max_count is reasonable (0 <= n <= 3),
 219          * there is no other revision filtering parameters.
 220          */
 221         if (revs->pending.nr || revs->max_count > 3 ||
 222             revs->min_age != -1 || revs->max_age != -1)
 223                 return error("no revision allowed with diff-files");
 224
 225         if (revs->max_count == -1 &&
 226             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 227                 revs->combine_merges = revs->dense_combined_merges = 1;
 228
 229         return 0;
 230 }
 231
 232 static int is_outside_repo(const char *path, int nongit, const char *prefix)
 233 {
 234         int i;
 235         if (nongit || !strcmp(path, "-") || is_absolute_path(path))
 236                 return 1;
 237         if (prefixcmp(path, "../"))
 238                 return 0;
 239         if (!prefix)
 240                 return 1;
 241         for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
 242                 while (i > 0 && prefix[i - 1] != '/')
 243                         i--;
 244                 if (--i < 0)
 245                         return 1;
 246                 path += 3;
 247         }
 248         return 0;
 249 }
 250
 251 int setup_diff_no_index(struct rev_info *revs,
 252                 int argc, const char ** argv, int nongit, const char *prefix)
 253 {
 254         int i;
 255         for (i = 1; i < argc; i++)
 256                 if (argv[i][0] != '-' || argv[i][1] == '\0')
 257                         break;
 258                 else if (!strcmp(argv[i], "--")) {
 259                         i++;
 260                         break;
 261                 } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
 262                         i = argc - 3;
 263                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
 264                         break;
 265                 }
 266         if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
 267                                 !is_outside_repo(argv[i], nongit, prefix)))
 268                 return -1;
 269
 270         diff_setup(&revs->diffopt);
 271         for (i = 1; i < argc - 2; )
 272                 if (!strcmp(argv[i], "--no-index"))
 273                         i++;
 274                 else {
 275                         int j = diff_opt_parse(&revs->diffopt,
 276                                         argv + i, argc - i);
 277                         if (!j)
 278                                 die("invalid diff option/value: %s", argv[i]);
 279                         i += j;
 280                 }
 281
 282         if (prefix) {
 283                 int len = strlen(prefix);
 284
 285                 revs->diffopt.paths = xcalloc(2, sizeof(char*));
 286                 for (i = 0; i < 2; i++) {
 287                         const char *p = argv[argc - 2 + i];
 288                         /*
 289                          * stdin should be spelled as '-'; if you have
 290                          * path that is '-', spell it as ./-.
 291                          */
 292                         p = (strcmp(p, "-")
 293                              ? xstrdup(prefix_filename(prefix, len, p))
 294                              : p);
 295                         revs->diffopt.paths[i] = p;
 296                 }
 297         }
 298         else
 299                 revs->diffopt.paths = argv + argc - 2;
 300         revs->diffopt.nr_paths = 2;
 301         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 302         revs->max_count = -2;
 303         if (diff_setup_done(&revs->diffopt) < 0)
 304                 die("diff_setup_done failed");
 305         return 0;
 306 }
 307
 308 int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
 309 {
 310         unsigned int options;
 311
 312         if (handle_diff_files_args(revs, argc, argv, &options))
 313                 return -1;
 314
 315         if (DIFF_OPT_TST(&revs->diffopt, NO_INDEX)) {
 316                 if (revs->diffopt.nr_paths != 2)
 317                         return error("need two files/directories with --no-index");
 318                 if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
 319                                 revs->diffopt.paths[1]))
 320                         return -1;
 321                 diffcore_std(&revs->diffopt);
 322                 diff_flush(&revs->diffopt);
 323                 /*
 324                  * The return code for --no-index imitates diff(1):
 325                  * 0 = no changes, 1 = changes, else error
 326                  */
 327                 return revs->diffopt.found_changes;
 328         }
 329
 330         if (read_cache() < 0) {
 331                 perror("read_cache");
 332                 return -1;
 333         }
 334         return run_diff_files(revs, options);
 335 }
 336
 337 int run_diff_files(struct rev_info *revs, unsigned int option)
 338 {
 339         int entries, i;
 340         int diff_unmerged_stage = revs->max_count;
 341         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
 342         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 343                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 344
 345         if (diff_unmerged_stage < 0)
 346                 diff_unmerged_stage = 2;
 347         entries = active_nr;
 348         for (i = 0; i < entries; i++) {
 349                 struct stat st;
 350                 unsigned int oldmode, newmode;
 351                 struct cache_entry *ce = active_cache[i];
 352                 int changed;
 353
 354                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
 355                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 356                         break;
 357
 358                 if (!ce_path_match(ce, revs->prune_data))
 359                         continue;
 360
 361                 if (ce_stage(ce)) {
 362                         struct combine_diff_path *dpath;
 363                         int num_compare_stages = 0;
 364                         size_t path_len;
 365
 366                         path_len = ce_namelen(ce);
 367
 368                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 369                         dpath->path = (char *) &(dpath->parent[5]);
 370
 371                         dpath->next = NULL;
 372                         dpath->len = path_len;
 373                         memcpy(dpath->path, ce->name, path_len);
 374                         dpath->path[path_len] = '\0';
 375                         hashclr(dpath->sha1);
 376                         memset(&(dpath->parent[0]), 0,
 377                                sizeof(struct combine_diff_parent)*5);
 378
 379                         if (lstat(ce->name, &st) < 0) {
 380                                 if (errno != ENOENT && errno != ENOTDIR) {
 381                                         perror(ce->name);
 382                                         continue;
 383                                 }
 384                                 if (silent_on_removed)
 385                                         continue;
 386                         }
 387                         else
 388                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
 389
 390                         while (i < entries) {
 391                                 struct cache_entry *nce = active_cache[i];
 392                                 int stage;
 393
 394                                 if (strcmp(ce->name, nce->name))
 395                                         break;
 396
 397                                 /* Stage #2 (ours) is the first parent,
 398                                  * stage #3 (theirs) is the second.
 399                                  */
 400                                 stage = ce_stage(nce);
 401                                 if (2 <= stage) {
 402                                         int mode = nce->ce_mode;
 403                                         num_compare_stages++;
 404                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 405                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 406                                         dpath->parent[stage-2].status =
 407                                                 DIFF_STATUS_MODIFIED;
 408                                 }
 409
 410                                 /* diff against the proper unmerged stage */
 411                                 if (stage == diff_unmerged_stage)
 412                                         ce = nce;
 413                                 i++;
 414                         }
 415                         /*
 416                          * Compensate for loop update
 417                          */
 418                         i--;
 419
 420                         if (revs->combine_merges && num_compare_stages == 2) {
 421                                 show_combined_diff(dpath, 2,
 422                                                    revs->dense_combined_merges,
 423                                                    revs);
 424                                 free(dpath);
 425                                 continue;
 426                         }
 427                         free(dpath);
 428                         dpath = NULL;
 429
 430                         /*
 431                          * Show the diff for the 'ce' if we found the one
 432                          * from the desired stage.
 433                          */
 434                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 435                         if (ce_stage(ce) != diff_unmerged_stage)
 436                                 continue;
 437                 }
 438
 439                 if (ce_uptodate(ce))
 440                         continue;
 441                 if (lstat(ce->name, &st) < 0) {
 442                         if (errno != ENOENT && errno != ENOTDIR) {
 443                                 perror(ce->name);
 444                                 continue;
 445                         }
 446                         if (silent_on_removed)
 447                                 continue;
 448                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 449                                        ce->sha1, ce->name, NULL);
 450                         continue;
 451                 }
 452                 changed = ce_match_stat(ce, &st, ce_option);
 453                 if (!changed && !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 454                         continue;
 455                 oldmode = ce->ce_mode;
 456                 newmode = ce_mode_from_stat(ce, st.st_mode);
 457                 diff_change(&revs->diffopt, oldmode, newmode,
 458                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 459                             ce->name, NULL);
 460
 461         }
 462         diffcore_std(&revs->diffopt);
 463         diff_flush(&revs->diffopt);
 464         return 0;
 465 }
 466
 467 /*
 468  * diff-index
 469  */
 470
 471 /* A file entry went away or appeared */
 472 static void diff_index_show_file(struct rev_info *revs,
 473                                  const char *prefix,
 474                                  struct cache_entry *ce,
 475                                  const unsigned char *sha1, unsigned int mode)
 476 {
 477         diff_addremove(&revs->diffopt, prefix[0], mode,
 478                        sha1, ce->name, NULL);
 479 }
 480
 481 static int get_stat_data(struct cache_entry *ce,
 482                          const unsigned char **sha1p,
 483                          unsigned int *modep,
 484                          int cached, int match_missing)
 485 {
 486         const unsigned char *sha1 = ce->sha1;
 487         unsigned int mode = ce->ce_mode;
 488
 489         if (!cached) {
 490                 int changed;
 491                 struct stat st;
 492                 if (lstat(ce->name, &st) < 0) {
 493                         if (errno == ENOENT && match_missing) {
 494                                 *sha1p = sha1;
 495                                 *modep = mode;
 496                                 return 0;
 497                         }
 498                         return -1;
 499                 }
 500                 changed = ce_match_stat(ce, &st, 0);
 501                 if (changed) {
 502                         mode = ce_mode_from_stat(ce, st.st_mode);
 503                         sha1 = null_sha1;
 504                 }
 505         }
 506
 507         *sha1p = sha1;
 508         *modep = mode;
 509         return 0;
 510 }
 511
 512 static void show_new_file(struct rev_info *revs,
 513                           struct cache_entry *new,
 514                           int cached, int match_missing)
 515 {
 516         const unsigned char *sha1;
 517         unsigned int mode;
 518
 519         /* New file in the index: it might actually be different in
 520          * the working copy.
 521          */
 522         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 523                 return;
 524
 525         diff_index_show_file(revs, "+", new, sha1, mode);
 526 }
 527
 528 static int show_modified(struct rev_info *revs,
 529                          struct cache_entry *old,
 530                          struct cache_entry *new,
 531                          int report_missing,
 532                          int cached, int match_missing)
 533 {
 534         unsigned int mode, oldmode;
 535         const unsigned char *sha1;
 536
 537         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 538                 if (report_missing)
 539                         diff_index_show_file(revs, "-", old,
 540                                              old->sha1, old->ce_mode);
 541                 return -1;
 542         }
 543
 544         if (revs->combine_merges && !cached &&
 545             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 546                 struct combine_diff_path *p;
 547                 int pathlen = ce_namelen(new);
 548
 549                 p = xmalloc(combine_diff_path_size(2, pathlen));
 550                 p->path = (char *) &p->parent[2];
 551                 p->next = NULL;
 552                 p->len = pathlen;
 553                 memcpy(p->path, new->name, pathlen);
 554                 p->path[pathlen] = 0;
 555                 p->mode = mode;
 556                 hashclr(p->sha1);
 557                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 558                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 559                 p->parent[0].mode = new->ce_mode;
 560                 hashcpy(p->parent[0].sha1, new->sha1);
 561                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 562                 p->parent[1].mode = old->ce_mode;
 563                 hashcpy(p->parent[1].sha1, old->sha1);
 564                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 565                 free(p);
 566                 return 0;
 567         }
 568
 569         oldmode = old->ce_mode;
 570         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 571             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 572                 return 0;
 573
 574         diff_change(&revs->diffopt, oldmode, mode,
 575                     old->sha1, sha1, old->name, NULL);
 576         return 0;
 577 }
 578
 579 /*
 580  * This turns all merge entries into "stage 3". That guarantees that
 581  * when we read in the new tree (into "stage 1"), we won't lose sight
 582  * of the fact that we had unmerged entries.
 583  */
 584 static void mark_merge_entries(void)
 585 {
 586         int i;
 587         for (i = 0; i < active_nr; i++) {
 588                 struct cache_entry *ce = active_cache[i];
 589                 if (!ce_stage(ce))
 590                         continue;
 591                 ce->ce_flags |= CE_STAGEMASK;
 592         }
 593 }
 594
 595 /*
 596  * This gets a mix of an existing index and a tree, one pathname entry
 597  * at a time. The index entry may be a single stage-0 one, but it could
 598  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 599  * give you the position and number of entries in the index).
 600  */
 601 static void do_oneway_diff(struct unpack_trees_options *o,
 602         struct cache_entry *idx,
 603         struct cache_entry *tree,
 604         int idx_pos, int idx_nr)
 605 {
 606         struct rev_info *revs = o->unpack_data;
 607         int match_missing, cached;
 608
 609         /*
 610          * Backward compatibility wart - "diff-index -m" does
 611          * not mean "do not ignore merges", but "match_missing".
 612          *
 613          * But with the revision flag parsing, that's found in
 614          * "!revs->ignore_merges".
 615          */
 616         cached = o->index_only;
 617         match_missing = !revs->ignore_merges;
 618
 619         if (cached && idx && ce_stage(idx)) {
 620                 if (tree)
 621                         diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
 622                 return;
 623         }
 624
 625         /*
 626          * Something added to the tree?
 627          */
 628         if (!tree) {
 629                 show_new_file(revs, idx, cached, match_missing);
 630                 return;
 631         }
 632
 633         /*
 634          * Something removed from the tree?
 635          */
 636         if (!idx) {
 637                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
 638                 return;
 639         }
 640
 641         /* Show difference between old and new */
 642         show_modified(revs, tree, idx, 1, cached, match_missing);
 643 }
 644
 645 /*
 646  * Count how many index entries go with the first one
 647  */
 648 static inline int count_skip(const struct cache_entry *src, int pos)
 649 {
 650         int skip = 1;
 651
 652         /* We can only have multiple entries if the first one is not stage-0 */
 653         if (ce_stage(src)) {
 654                 struct cache_entry **p = active_cache + pos;
 655                 int namelen = ce_namelen(src);
 656
 657                 for (;;) {
 658                         const struct cache_entry *ce;
 659                         pos++;
 660                         if (pos >= active_nr)
 661                                 break;
 662                         ce = *++p;
 663                         if (ce_namelen(ce) != namelen)
 664                                 break;
 665                         if (memcmp(ce->name, src->name, namelen))
 666                                 break;
 667                         skip++;
 668                 }
 669         }
 670         return skip;
 671 }
 672
 673 /*
 674  * The unpack_trees() interface is designed for merging, so
 675  * the different source entries are designed primarily for
 676  * the source trees, with the old index being really mainly
 677  * used for being replaced by the result.
 678  *
 679  * For diffing, the index is more important, and we only have a
 680  * single tree.
 681  *
 682  * We're supposed to return how many index entries we want to skip.
 683  *
 684  * This wrapper makes it all more readable, and takes care of all
 685  * the fairly complex unpack_trees() semantic requirements, including
 686  * the skipping, the path matching, the type conflict cases etc.
 687  */
 688 static int oneway_diff(struct cache_entry **src,
 689         struct unpack_trees_options *o,
 690         int index_pos)
 691 {
 692         int skip = 0;
 693         struct cache_entry *idx = src[0];
 694         struct cache_entry *tree = src[1];
 695         struct rev_info *revs = o->unpack_data;
 696
 697         if (index_pos >= 0)
 698                 skip = count_skip(idx, index_pos);
 699
 700         /*
 701          * Unpack-trees generates a DF/conflict entry if
 702          * there was a directory in the index and a tree
 703          * in the tree. From a diff standpoint, that's a
 704          * delete of the tree and a create of the file.
 705          */
 706         if (tree == o->df_conflict_entry)
 707                 tree = NULL;
 708
 709         if (ce_path_match(idx ? idx : tree, revs->prune_data))
 710                 do_oneway_diff(o, idx, tree, index_pos, skip);
 711
 712         return skip;
 713 }
 714
 715 int run_diff_index(struct rev_info *revs, int cached)
 716 {
 717         struct object *ent;
 718         struct tree *tree;
 719         const char *tree_name;
 720         struct unpack_trees_options opts;
 721         struct tree_desc t;
 722
 723         mark_merge_entries();
 724
 725         ent = revs->pending.objects[0].item;
 726         tree_name = revs->pending.objects[0].name;
 727         tree = parse_tree_indirect(ent->sha1);
 728         if (!tree)
 729                 return error("bad tree object %s", tree_name);
 730
 731         memset(&opts, 0, sizeof(opts));
 732         opts.head_idx = 1;
 733         opts.index_only = cached;
 734         opts.merge = 1;
 735         opts.fn = oneway_diff;
 736         opts.unpack_data = revs;
 737
 738         init_tree_desc(&t, tree->buffer, tree->size);
 739         if (unpack_trees(1, &t, &opts))
 740                 exit(128);
 741
 742         diffcore_std(&revs->diffopt);
 743         diff_flush(&revs->diffopt);
 744         return 0;
 745 }
 746
 747 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 748 {
 749         struct tree *tree;
 750         struct rev_info revs;
 751         int i;
 752         struct cache_entry **dst;
 753         struct cache_entry *last = NULL;
 754         struct unpack_trees_options opts;
 755         struct tree_desc t;
 756
 757         /*
 758          * This is used by git-blame to run diff-cache internally;
 759          * it potentially needs to repeatedly run this, so we will
 760          * start by removing the higher order entries the last round
 761          * left behind.
 762          */
 763         dst = active_cache;
 764         for (i = 0; i < active_nr; i++) {
 765                 struct cache_entry *ce = active_cache[i];
 766                 if (ce_stage(ce)) {
 767                         if (last && !strcmp(ce->name, last->name))
 768                                 continue;
 769                         cache_tree_invalidate_path(active_cache_tree,
 770                                                    ce->name);
 771                         last = ce;
 772                         ce->ce_flags |= CE_REMOVE;
 773                 }
 774                 *dst++ = ce;
 775         }
 776         active_nr = dst - active_cache;
 777
 778         init_revisions(&revs, NULL);
 779         revs.prune_data = opt->paths;
 780         tree = parse_tree_indirect(tree_sha1);
 781         if (!tree)
 782                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 783
 784         memset(&opts, 0, sizeof(opts));
 785         opts.head_idx = 1;
 786         opts.index_only = 1;
 787         opts.merge = 1;
 788         opts.fn = oneway_diff;
 789         opts.unpack_data = &revs;
 790
 791         init_tree_desc(&t, tree->buffer, tree->size);
 792         if (unpack_trees(1, &t, &opts))
 793                 exit(128);
 794         return 0;
 795 }