diff-lib.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "git-compat-util.h"
   5 #include "quote.h"
   6 #include "commit.h"
   7 #include "diff.h"
   8 #include "diffcore.h"
   9 #include "gettext.h"
  10 #include "hex.h"
  11 #include "object-name.h"
  12 #include "read-cache.h"
  13 #include "revision.h"
  14 #include "cache-tree.h"
  15 #include "unpack-trees.h"
  16 #include "refs.h"
  17 #include "submodule.h"
  18 #include "symlinks.h"
  19 #include "trace.h"
  20 #include "dir.h"
  21 #include "fsmonitor.h"
  22 #include "commit-reach.h"
  23
  24 /*
  25  * diff-files
  26  */
  27
  28 /*
  29  * Has the work tree entity been removed?
  30  *
  31  * Return 1 if it was removed from the work tree, 0 if an entity to be
  32  * compared with the cache entry ce still exists (the latter includes
  33  * the case where a directory that is not a submodule repository
  34  * exists for ce that is a submodule -- it is a submodule that is not
  35  * checked out).  Return negative for an error.
  36  */
  37 static int check_removed(const struct index_state *istate, const struct cache_entry *ce, struct stat *st)
  38 {
  39         assert(is_fsmonitor_refreshed(istate));
  40         if (!(ce->ce_flags & CE_FSMONITOR_VALID) && lstat(ce->name, st) < 0) {
  41                 if (!is_missing_file_error(errno))
  42                         return -1;
  43                 return 1;
  44         }
  45         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  46                 return 1;
  47         if (S_ISDIR(st->st_mode)) {
  48                 struct object_id sub;
  49
  50                 /*
  51                  * If ce is already a gitlink, we can have a plain
  52                  * directory (i.e. the submodule is not checked out),
  53                  * or a checked out submodule.  Either case this is not
  54                  * a case where something was removed from the work tree,
  55                  * so we will return 0.
  56                  *
  57                  * Otherwise, if the directory is not a submodule
  58                  * repository, that means ce which was a blob turned into
  59                  * a directory --- the blob was removed!
  60                  */
  61                 if (!S_ISGITLINK(ce->ce_mode) &&
  62                     resolve_gitlink_ref(ce->name, "HEAD", &sub))
  63                         return 1;
  64         }
  65         return 0;
  66 }
  67
  68 /*
  69  * Has a file changed or has a submodule new commits or a dirty work tree?
  70  *
  71  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  72  * option is set, the caller does not only want to know if a submodule is
  73  * modified at all but wants to know all the conditions that are met (new
  74  * commits, untracked content and/or modified content).
  75  */
  76 static int match_stat_with_submodule(struct diff_options *diffopt,
  77                                      const struct cache_entry *ce,
  78                                      struct stat *st, unsigned ce_option,
  79                                      unsigned *dirty_submodule)
  80 {
  81         int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);
  82         if (S_ISGITLINK(ce->ce_mode)) {
  83                 struct diff_flags orig_flags = diffopt->flags;
  84                 if (!diffopt->flags.override_submodule_config)
  85                         set_diffopt_flags_from_submodule_config(diffopt, ce->name);
  86                 if (diffopt->flags.ignore_submodules)
  87                         changed = 0;
  88                 else if (!diffopt->flags.ignore_dirty_submodules &&
  89                          (!changed || diffopt->flags.dirty_submodules))
  90                         *dirty_submodule = is_submodule_modified(ce->name,
  91                                                                  diffopt->flags.ignore_untracked_in_submodules);
  92                 diffopt->flags = orig_flags;
  93         }
  94         return changed;
  95 }
  96
  97 int run_diff_files(struct rev_info *revs, unsigned int option)
  98 {
  99         int entries, i;
 100         int diff_unmerged_stage = revs->max_count;
 101         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 102                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 103         uint64_t start = getnanotime();
 104         struct index_state *istate = revs->diffopt.repo->index;
 105
 106         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 107
 108         refresh_fsmonitor(istate);
 109
 110         if (diff_unmerged_stage < 0)
 111                 diff_unmerged_stage = 2;
 112         entries = istate->cache_nr;
 113         for (i = 0; i < entries; i++) {
 114                 unsigned int oldmode, newmode;
 115                 struct cache_entry *ce = istate->cache[i];
 116                 int changed;
 117                 unsigned dirty_submodule = 0;
 118                 const struct object_id *old_oid, *new_oid;
 119
 120                 if (diff_can_quit_early(&revs->diffopt))
 121                         break;
 122
 123                 if (!ce_path_match(istate, ce, &revs->prune_data, NULL))
 124                         continue;
 125
 126                 if (revs->diffopt.prefix &&
 127                     strncmp(ce->name, revs->diffopt.prefix, revs->diffopt.prefix_length))
 128                         continue;
 129
 130                 if (ce_stage(ce)) {
 131                         struct combine_diff_path *dpath;
 132                         struct diff_filepair *pair;
 133                         unsigned int wt_mode = 0;
 134                         int num_compare_stages = 0;
 135                         size_t path_len;
 136                         struct stat st;
 137
 138                         path_len = ce_namelen(ce);
 139
 140                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 141                         dpath->path = (char *) &(dpath->parent[5]);
 142
 143                         dpath->next = NULL;
 144                         memcpy(dpath->path, ce->name, path_len);
 145                         dpath->path[path_len] = '\0';
 146                         oidclr(&dpath->oid);
 147                         memset(&(dpath->parent[0]), 0,
 148                                sizeof(struct combine_diff_parent)*5);
 149
 150                         changed = check_removed(istate, ce, &st);
 151                         if (!changed)
 152                                 wt_mode = ce_mode_from_stat(ce, st.st_mode);
 153                         else {
 154                                 if (changed < 0) {
 155                                         perror(ce->name);
 156                                         continue;
 157                                 }
 158                                 wt_mode = 0;
 159                         }
 160                         dpath->mode = wt_mode;
 161
 162                         while (i < entries) {
 163                                 struct cache_entry *nce = istate->cache[i];
 164                                 int stage;
 165
 166                                 if (strcmp(ce->name, nce->name))
 167                                         break;
 168
 169                                 /* Stage #2 (ours) is the first parent,
 170                                  * stage #3 (theirs) is the second.
 171                                  */
 172                                 stage = ce_stage(nce);
 173                                 if (2 <= stage) {
 174                                         int mode = nce->ce_mode;
 175                                         num_compare_stages++;
 176                                         oidcpy(&dpath->parent[stage - 2].oid,
 177                                                &nce->oid);
 178                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 179                                         dpath->parent[stage-2].status =
 180                                                 DIFF_STATUS_MODIFIED;
 181                                 }
 182
 183                                 /* diff against the proper unmerged stage */
 184                                 if (stage == diff_unmerged_stage)
 185                                         ce = nce;
 186                                 i++;
 187                         }
 188                         /*
 189                          * Compensate for loop update
 190                          */
 191                         i--;
 192
 193                         if (revs->combine_merges && num_compare_stages == 2) {
 194                                 show_combined_diff(dpath, 2, revs);
 195                                 free(dpath);
 196                                 continue;
 197                         }
 198                         FREE_AND_NULL(dpath);
 199
 200                         /*
 201                          * Show the diff for the 'ce' if we found the one
 202                          * from the desired stage.
 203                          */
 204                         pair = diff_unmerge(&revs->diffopt, ce->name);
 205                         if (wt_mode)
 206                                 pair->two->mode = wt_mode;
 207                         if (ce_stage(ce) != diff_unmerged_stage)
 208                                 continue;
 209                 }
 210
 211                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
 212                         continue;
 213
 214                 /*
 215                  * When CE_VALID is set (via "update-index --assume-unchanged"
 216                  * or via adding paths while core.ignorestat is set to true),
 217                  * the user has promised that the working tree file for that
 218                  * path will not be modified.  When CE_FSMONITOR_VALID is true,
 219                  * the fsmonitor knows that the path hasn't been modified since
 220                  * we refreshed the cached stat information.  In either case,
 221                  * we do not have to stat to see if the path has been removed
 222                  * or modified.
 223                  */
 224                 if (ce->ce_flags & (CE_VALID | CE_FSMONITOR_VALID)) {
 225                         changed = 0;
 226                         newmode = ce->ce_mode;
 227                 } else {
 228                         struct stat st;
 229
 230                         changed = check_removed(istate, ce, &st);
 231                         if (changed) {
 232                                 if (changed < 0) {
 233                                         perror(ce->name);
 234                                         continue;
 235                                 }
 236                                 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 237                                                &ce->oid,
 238                                                !is_null_oid(&ce->oid),
 239                                                ce->name, 0);
 240                                 continue;
 241                         } else if (revs->diffopt.ita_invisible_in_index &&
 242                                    ce_intent_to_add(ce)) {
 243                                 newmode = ce_mode_from_stat(ce, st.st_mode);
 244                                 diff_addremove(&revs->diffopt, '+', newmode,
 245                                                null_oid(), 0, ce->name, 0);
 246                                 continue;
 247                         }
 248
 249                         changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 250                                                             ce_option, &dirty_submodule);
 251                         newmode = ce_mode_from_stat(ce, st.st_mode);
 252                 }
 253
 254                 if (!changed && !dirty_submodule) {
 255                         ce_mark_uptodate(ce);
 256                         mark_fsmonitor_valid(istate, ce);
 257                         if (!revs->diffopt.flags.find_copies_harder)
 258                                 continue;
 259                 }
 260                 oldmode = ce->ce_mode;
 261                 old_oid = &ce->oid;
 262                 new_oid = changed ? null_oid() : &ce->oid;
 263                 diff_change(&revs->diffopt, oldmode, newmode,
 264                             old_oid, new_oid,
 265                             !is_null_oid(old_oid),
 266                             !is_null_oid(new_oid),
 267                             ce->name, 0, dirty_submodule);
 268
 269         }
 270         diffcore_std(&revs->diffopt);
 271         diff_flush(&revs->diffopt);
 272         trace_performance_since(start, "diff-files");
 273         return 0;
 274 }
 275
 276 /*
 277  * diff-index
 278  */
 279
 280 /* A file entry went away or appeared */
 281 static void diff_index_show_file(struct rev_info *revs,
 282                                  const char *prefix,
 283                                  const struct cache_entry *ce,
 284                                  const struct object_id *oid, int oid_valid,
 285                                  unsigned int mode,
 286                                  unsigned dirty_submodule)
 287 {
 288         diff_addremove(&revs->diffopt, prefix[0], mode,
 289                        oid, oid_valid, ce->name, dirty_submodule);
 290 }
 291
 292 static int get_stat_data(const struct index_state *istate,
 293                          const struct cache_entry *ce,
 294                          const struct object_id **oidp,
 295                          unsigned int *modep,
 296                          int cached, int match_missing,
 297                          unsigned *dirty_submodule, struct diff_options *diffopt)
 298 {
 299         const struct object_id *oid = &ce->oid;
 300         unsigned int mode = ce->ce_mode;
 301
 302         if (!cached && !ce_uptodate(ce)) {
 303                 int changed;
 304                 struct stat st;
 305                 changed = check_removed(istate, ce, &st);
 306                 if (changed < 0)
 307                         return -1;
 308                 else if (changed) {
 309                         if (match_missing) {
 310                                 *oidp = oid;
 311                                 *modep = mode;
 312                                 return 0;
 313                         }
 314                         return -1;
 315                 }
 316                 changed = match_stat_with_submodule(diffopt, ce, &st,
 317                                                     0, dirty_submodule);
 318                 if (changed) {
 319                         mode = ce_mode_from_stat(ce, st.st_mode);
 320                         oid = null_oid();
 321                 }
 322         }
 323
 324         *oidp = oid;
 325         *modep = mode;
 326         return 0;
 327 }
 328
 329 static void show_new_file(struct rev_info *revs,
 330                           const struct cache_entry *new_file,
 331                           int cached, int match_missing)
 332 {
 333         const struct object_id *oid;
 334         unsigned int mode;
 335         unsigned dirty_submodule = 0;
 336         struct index_state *istate = revs->diffopt.repo->index;
 337
 338         if (new_file && S_ISSPARSEDIR(new_file->ce_mode)) {
 339                 diff_tree_oid(NULL, &new_file->oid, new_file->name, &revs->diffopt);
 340                 return;
 341         }
 342
 343         /*
 344          * New file in the index: it might actually be different in
 345          * the working tree.
 346          */
 347         if (get_stat_data(istate, new_file, &oid, &mode, cached, match_missing,
 348             &dirty_submodule, &revs->diffopt) < 0)
 349                 return;
 350
 351         diff_index_show_file(revs, "+", new_file, oid, !is_null_oid(oid), mode, dirty_submodule);
 352 }
 353
 354 static int show_modified(struct rev_info *revs,
 355                          const struct cache_entry *old_entry,
 356                          const struct cache_entry *new_entry,
 357                          int report_missing,
 358                          int cached, int match_missing)
 359 {
 360         unsigned int mode, oldmode;
 361         const struct object_id *oid;
 362         unsigned dirty_submodule = 0;
 363         struct index_state *istate = revs->diffopt.repo->index;
 364
 365         assert(S_ISSPARSEDIR(old_entry->ce_mode) ==
 366                S_ISSPARSEDIR(new_entry->ce_mode));
 367
 368         /*
 369          * If both are sparse directory entries, then expand the
 370          * modifications to the file level. If only one was a sparse
 371          * directory, then they appear as an add and delete instead of
 372          * a modification.
 373          */
 374         if (S_ISSPARSEDIR(new_entry->ce_mode)) {
 375                 diff_tree_oid(&old_entry->oid, &new_entry->oid, new_entry->name, &revs->diffopt);
 376                 return 0;
 377         }
 378
 379         if (get_stat_data(istate, new_entry, &oid, &mode, cached, match_missing,
 380                           &dirty_submodule, &revs->diffopt) < 0) {
 381                 if (report_missing)
 382                         diff_index_show_file(revs, "-", old_entry,
 383                                              &old_entry->oid, 1, old_entry->ce_mode,
 384                                              0);
 385                 return -1;
 386         }
 387
 388         if (revs->combine_merges && !cached &&
 389             (!oideq(oid, &old_entry->oid) || !oideq(&old_entry->oid, &new_entry->oid))) {
 390                 struct combine_diff_path *p;
 391                 int pathlen = ce_namelen(new_entry);
 392
 393                 p = xmalloc(combine_diff_path_size(2, pathlen));
 394                 p->path = (char *) &p->parent[2];
 395                 p->next = NULL;
 396                 memcpy(p->path, new_entry->name, pathlen);
 397                 p->path[pathlen] = 0;
 398                 p->mode = mode;
 399                 oidclr(&p->oid);
 400                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 401                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 402                 p->parent[0].mode = new_entry->ce_mode;
 403                 oidcpy(&p->parent[0].oid, &new_entry->oid);
 404                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 405                 p->parent[1].mode = old_entry->ce_mode;
 406                 oidcpy(&p->parent[1].oid, &old_entry->oid);
 407                 show_combined_diff(p, 2, revs);
 408                 free(p);
 409                 return 0;
 410         }
 411
 412         oldmode = old_entry->ce_mode;
 413         if (mode == oldmode && oideq(oid, &old_entry->oid) && !dirty_submodule &&
 414             !revs->diffopt.flags.find_copies_harder)
 415                 return 0;
 416
 417         diff_change(&revs->diffopt, oldmode, mode,
 418                     &old_entry->oid, oid, 1, !is_null_oid(oid),
 419                     old_entry->name, 0, dirty_submodule);
 420         return 0;
 421 }
 422
 423 /*
 424  * This gets a mix of an existing index and a tree, one pathname entry
 425  * at a time. The index entry may be a single stage-0 one, but it could
 426  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 427  * give you the position and number of entries in the index).
 428  */
 429 static void do_oneway_diff(struct unpack_trees_options *o,
 430                            const struct cache_entry *idx,
 431                            const struct cache_entry *tree)
 432 {
 433         struct rev_info *revs = o->unpack_data;
 434         int match_missing, cached;
 435
 436         /*
 437          * i-t-a entries do not actually exist in the index (if we're
 438          * looking at its content)
 439          */
 440         if (o->index_only &&
 441             revs->diffopt.ita_invisible_in_index &&
 442             idx && ce_intent_to_add(idx)) {
 443                 idx = NULL;
 444                 if (!tree)
 445                         return; /* nothing to diff.. */
 446         }
 447
 448         /* if the entry is not checked out, don't examine work tree */
 449         cached = o->index_only ||
 450                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 451
 452         match_missing = revs->match_missing;
 453
 454         if (cached && idx && ce_stage(idx)) {
 455                 struct diff_filepair *pair;
 456                 pair = diff_unmerge(&revs->diffopt, idx->name);
 457                 if (tree)
 458                         fill_filespec(pair->one, &tree->oid, 1,
 459                                       tree->ce_mode);
 460                 return;
 461         }
 462
 463         /*
 464          * Something added to the tree?
 465          */
 466         if (!tree) {
 467                 show_new_file(revs, idx, cached, match_missing);
 468                 return;
 469         }
 470
 471         /*
 472          * Something removed from the tree?
 473          */
 474         if (!idx) {
 475                 if (S_ISSPARSEDIR(tree->ce_mode)) {
 476                         diff_tree_oid(&tree->oid, NULL, tree->name, &revs->diffopt);
 477                         return;
 478                 }
 479
 480                 diff_index_show_file(revs, "-", tree, &tree->oid, 1,
 481                                      tree->ce_mode, 0);
 482                 return;
 483         }
 484
 485         /* Show difference between old and new */
 486         show_modified(revs, tree, idx, 1, cached, match_missing);
 487 }
 488
 489 /*
 490  * The unpack_trees() interface is designed for merging, so
 491  * the different source entries are designed primarily for
 492  * the source trees, with the old index being really mainly
 493  * used for being replaced by the result.
 494  *
 495  * For diffing, the index is more important, and we only have a
 496  * single tree.
 497  *
 498  * We're supposed to advance o->pos to skip what we have already processed.
 499  *
 500  * This wrapper makes it all more readable, and takes care of all
 501  * the fairly complex unpack_trees() semantic requirements, including
 502  * the skipping, the path matching, the type conflict cases etc.
 503  */
 504 static int oneway_diff(const struct cache_entry * const *src,
 505                        struct unpack_trees_options *o)
 506 {
 507         const struct cache_entry *idx = src[0];
 508         const struct cache_entry *tree = src[1];
 509         struct rev_info *revs = o->unpack_data;
 510
 511         /*
 512          * Unpack-trees generates a DF/conflict entry if
 513          * there was a directory in the index and a tree
 514          * in the tree. From a diff standpoint, that's a
 515          * delete of the tree and a create of the file.
 516          */
 517         if (tree == o->df_conflict_entry)
 518                 tree = NULL;
 519
 520         if (ce_path_match(revs->diffopt.repo->index,
 521                           idx ? idx : tree,
 522                           &revs->prune_data, NULL)) {
 523                 do_oneway_diff(o, idx, tree);
 524                 if (diff_can_quit_early(&revs->diffopt)) {
 525                         o->exiting_early = 1;
 526                         return -1;
 527                 }
 528         }
 529
 530         return 0;
 531 }
 532
 533 static int diff_cache(struct rev_info *revs,
 534                       const struct object_id *tree_oid,
 535                       const char *tree_name,
 536                       int cached)
 537 {
 538         struct tree *tree;
 539         struct tree_desc t;
 540         struct unpack_trees_options opts;
 541
 542         tree = parse_tree_indirect(tree_oid);
 543         if (!tree)
 544                 return error("bad tree object %s",
 545                              tree_name ? tree_name : oid_to_hex(tree_oid));
 546         memset(&opts, 0, sizeof(opts));
 547         opts.head_idx = 1;
 548         opts.index_only = cached;
 549         opts.diff_index_cached = (cached &&
 550                                   !revs->diffopt.flags.find_copies_harder);
 551         opts.merge = 1;
 552         opts.fn = oneway_diff;
 553         opts.unpack_data = revs;
 554         opts.src_index = revs->diffopt.repo->index;
 555         opts.dst_index = NULL;
 556         opts.pathspec = &revs->diffopt.pathspec;
 557         opts.pathspec->recursive = 1;
 558
 559         init_tree_desc(&t, tree->buffer, tree->size);
 560         return unpack_trees(1, &t, &opts);
 561 }
 562
 563 void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
 564 {
 565         int i;
 566         struct commit *mb_child[2] = {0};
 567         struct commit_list *merge_bases;
 568
 569         for (i = 0; i < revs->pending.nr; i++) {
 570                 struct object *obj = revs->pending.objects[i].item;
 571                 if (obj->flags)
 572                         die(_("--merge-base does not work with ranges"));
 573                 if (obj->type != OBJ_COMMIT)
 574                         die(_("--merge-base only works with commits"));
 575         }
 576
 577         /*
 578          * This check must go after the for loop above because A...B
 579          * ranges produce three pending commits, resulting in a
 580          * misleading error message.
 581          */
 582         if (revs->pending.nr < 1 || revs->pending.nr > 2)
 583                 BUG("unexpected revs->pending.nr: %d", revs->pending.nr);
 584
 585         for (i = 0; i < revs->pending.nr; i++)
 586                 mb_child[i] = lookup_commit_reference(the_repository, &revs->pending.objects[i].item->oid);
 587         if (revs->pending.nr == 1) {
 588                 struct object_id oid;
 589
 590                 if (repo_get_oid(the_repository, "HEAD", &oid))
 591                         die(_("unable to get HEAD"));
 592
 593                 mb_child[1] = lookup_commit_reference(the_repository, &oid);
 594         }
 595
 596         merge_bases = repo_get_merge_bases(the_repository, mb_child[0], mb_child[1]);
 597         if (!merge_bases)
 598                 die(_("no merge base found"));
 599         if (merge_bases->next)
 600                 die(_("multiple merge bases found"));
 601
 602         oidcpy(mb, &merge_bases->item->object.oid);
 603
 604         free_commit_list(merge_bases);
 605 }
 606
 607 int run_diff_index(struct rev_info *revs, unsigned int option)
 608 {
 609         struct object_array_entry *ent;
 610         int cached = !!(option & DIFF_INDEX_CACHED);
 611         int merge_base = !!(option & DIFF_INDEX_MERGE_BASE);
 612         struct object_id oid;
 613         const char *name;
 614         char merge_base_hex[GIT_MAX_HEXSZ + 1];
 615         struct index_state *istate = revs->diffopt.repo->index;
 616
 617         if (revs->pending.nr != 1)
 618                 BUG("run_diff_index must be passed exactly one tree");
 619
 620         trace_performance_enter();
 621         ent = revs->pending.objects;
 622
 623         refresh_fsmonitor(istate);
 624
 625         if (merge_base) {
 626                 diff_get_merge_base(revs, &oid);
 627                 name = oid_to_hex_r(merge_base_hex, &oid);
 628         } else {
 629                 oidcpy(&oid, &ent->item->oid);
 630                 name = ent->name;
 631         }
 632
 633         if (diff_cache(revs, &oid, name, cached))
 634                 exit(128);
 635
 636         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 637         diffcore_fix_diff_index();
 638         diffcore_std(&revs->diffopt);
 639         diff_flush(&revs->diffopt);
 640         trace_performance_leave("diff-index");
 641         return 0;
 642 }
 643
 644 int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
 645 {
 646         struct rev_info revs;
 647
 648         repo_init_revisions(opt->repo, &revs, NULL);
 649         copy_pathspec(&revs.prune_data, &opt->pathspec);
 650         diff_setup_done(&revs.diffopt);
 651         revs.diffopt = *opt;
 652
 653         if (diff_cache(&revs, tree_oid, NULL, 1))
 654                 exit(128);
 655         release_revisions(&revs);
 656         return 0;
 657 }
 658
 659 int index_differs_from(struct repository *r,
 660                        const char *def, const struct diff_flags *flags,
 661                        int ita_invisible_in_index)
 662 {
 663         struct rev_info rev;
 664         struct setup_revision_opt opt;
 665         unsigned has_changes;
 666
 667         repo_init_revisions(r, &rev, NULL);
 668         memset(&opt, 0, sizeof(opt));
 669         opt.def = def;
 670         setup_revisions(0, NULL, &rev, &opt);
 671         rev.diffopt.flags.quick = 1;
 672         rev.diffopt.flags.exit_with_status = 1;
 673         if (flags)
 674                 diff_flags_or(&rev.diffopt.flags, flags);
 675         rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
 676         run_diff_index(&rev, 1);
 677         has_changes = rev.diffopt.flags.has_changes;
 678         release_revisions(&rev);
 679         return (has_changes != 0);
 680 }
 681
 682 static struct strbuf *idiff_prefix_cb(struct diff_options *opt UNUSED, void *data)
 683 {
 684         return data;
 685 }
 686
 687 void show_interdiff(const struct object_id *oid1, const struct object_id *oid2,
 688                     int indent, struct diff_options *diffopt)
 689 {
 690         struct diff_options opts;
 691         struct strbuf prefix = STRBUF_INIT;
 692
 693         memcpy(&opts, diffopt, sizeof(opts));
 694         opts.output_format = DIFF_FORMAT_PATCH;
 695         opts.output_prefix = idiff_prefix_cb;
 696         strbuf_addchars(&prefix, ' ', indent);
 697         opts.output_prefix_data = &prefix;
 698         diff_setup_done(&opts);
 699
 700         diff_tree_oid(oid1, oid2, "", &opts);
 701         diffcore_std(&opts);
 702         diff_flush(&opts);
 703
 704         strbuf_release(&prefix);
 705 }