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