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 "hash.h"
  11 #include "hex.h"
  12 #include "object-name.h"
  13 #include "read-cache.h"
  14 #include "revision.h"
  15 #include "cache-tree.h"
  16 #include "unpack-trees.h"
  17 #include "refs.h"
  18 #include "repository.h"
  19 #include "submodule.h"
  20 #include "symlinks.h"
  21 #include "trace.h"
  22 #include "dir.h"
  23 #include "fsmonitor.h"
  24 #include "commit-reach.h"
  25
  26 /*
  27  * diff-files
  28  */
  29
  30 /*
  31  * Has the work tree entity been removed?
  32  *
  33  * Return 1 if it was removed from the work tree, 0 if an entity to be
  34  * compared with the cache entry ce still exists (the latter includes
  35  * the case where a directory that is not a submodule repository
  36  * exists for ce that is a submodule -- it is a submodule that is not
  37  * checked out).  Return negative for an error.
  38  */
  39 static int check_removed(const struct cache_entry *ce, struct stat *st)
  40 {
  41         if (lstat(ce->name, st) < 0) {
  42                 if (!is_missing_file_error(errno))
  43                         return -1;
  44                 return 1;
  45         }
  46
  47         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  48                 return 1;
  49         if (S_ISDIR(st->st_mode)) {
  50                 struct object_id sub;
  51
  52                 /*
  53                  * If ce is already a gitlink, we can have a plain
  54                  * directory (i.e. the submodule is not checked out),
  55                  * or a checked out submodule.  Either case this is not
  56                  * a case where something was removed from the work tree,
  57                  * so we will return 0.
  58                  *
  59                  * Otherwise, if the directory is not a submodule
  60                  * repository, that means ce which was a blob turned into
  61                  * a directory --- the blob was removed!
  62                  */
  63                 if (!S_ISGITLINK(ce->ce_mode) &&
  64                     resolve_gitlink_ref(ce->name, "HEAD", &sub))
  65                         return 1;
  66         }
  67         return 0;
  68 }
  69
  70 /*
  71  * Has a file changed or has a submodule new commits or a dirty work tree?
  72  *
  73  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  74  * option is set, the caller does not only want to know if a submodule is
  75  * modified at all but wants to know all the conditions that are met (new
  76  * commits, untracked content and/or modified content).
  77  */
  78 static int match_stat_with_submodule(struct diff_options *diffopt,
  79                                      const struct cache_entry *ce,
  80                                      struct stat *st, unsigned ce_option,
  81                                      unsigned *dirty_submodule)
  82 {
  83         int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);
  84         if (S_ISGITLINK(ce->ce_mode)) {
  85                 struct diff_flags orig_flags = diffopt->flags;
  86                 if (!diffopt->flags.override_submodule_config)
  87                         set_diffopt_flags_from_submodule_config(diffopt, ce->name);
  88                 if (diffopt->flags.ignore_submodules)
  89                         changed = 0;
  90                 else if (!diffopt->flags.ignore_dirty_submodules &&
  91                          (!changed || diffopt->flags.dirty_submodules))
  92                         *dirty_submodule = is_submodule_modified(ce->name,
  93                                                                  diffopt->flags.ignore_untracked_in_submodules);
  94                 diffopt->flags = orig_flags;
  95         }
  96         return changed;
  97 }
  98
  99 int run_diff_files(struct rev_info *revs, unsigned int option)
 100 {
 101         int entries, i;
 102         int diff_unmerged_stage = revs->max_count;
 103         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 104                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 105         uint64_t start = getnanotime();
 106         struct index_state *istate = revs->diffopt.repo->index;
 107
 108         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 109
 110         refresh_fsmonitor(istate);
 111
 112         if (diff_unmerged_stage < 0)
 113                 diff_unmerged_stage = 2;
 114         entries = istate->cache_nr;
 115         for (i = 0; i < entries; i++) {
 116                 unsigned int oldmode, newmode;
 117                 struct cache_entry *ce = istate->cache[i];
 118                 int changed;
 119                 unsigned dirty_submodule = 0;
 120                 const struct object_id *old_oid, *new_oid;
 121
 122                 if (diff_can_quit_early(&revs->diffopt))
 123                         break;
 124
 125                 if (!ce_path_match(istate, ce, &revs->prune_data, NULL))
 126                         continue;
 127
 128                 if (revs->diffopt.prefix &&
 129                     strncmp(ce->name, revs->diffopt.prefix, revs->diffopt.prefix_length))
 130                         continue;
 131
 132                 if (ce_stage(ce)) {
 133                         struct combine_diff_path *dpath;
 134                         struct diff_filepair *pair;
 135                         unsigned int wt_mode = 0;
 136                         int num_compare_stages = 0;
 137                         size_t path_len;
 138                         struct stat st;
 139
 140                         path_len = ce_namelen(ce);
 141
 142                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 143                         dpath->path = (char *) &(dpath->parent[5]);
 144
 145                         dpath->next = NULL;
 146                         memcpy(dpath->path, ce->name, path_len);
 147                         dpath->path[path_len] = '\0';
 148                         oidclr(&dpath->oid);
 149                         memset(&(dpath->parent[0]), 0,
 150                                sizeof(struct combine_diff_parent)*5);
 151
 152                         changed = check_removed(ce, &st);
 153                         if (!changed)
 154                                 wt_mode = ce_mode_from_stat(ce, st.st_mode);
 155                         else {
 156                                 if (changed < 0) {
 157                                         perror(ce->name);
 158                                         continue;
 159                                 }
 160                                 wt_mode = 0;
 161                         }
 162                         dpath->mode = wt_mode;
 163
 164                         while (i < entries) {
 165                                 struct cache_entry *nce = istate->cache[i];
 166                                 int stage;
 167
 168                                 if (strcmp(ce->name, nce->name))
 169                                         break;
 170
 171                                 /* Stage #2 (ours) is the first parent,
 172                                  * stage #3 (theirs) is the second.
 173                                  */
 174                                 stage = ce_stage(nce);
 175                                 if (2 <= stage) {
 176                                         int mode = nce->ce_mode;
 177                                         num_compare_stages++;
 178                                         oidcpy(&dpath->parent[stage - 2].oid,
 179                                                &nce->oid);
 180                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 181                                         dpath->parent[stage-2].status =
 182                                                 DIFF_STATUS_MODIFIED;
 183                                 }
 184
 185                                 /* diff against the proper unmerged stage */
 186                                 if (stage == diff_unmerged_stage)
 187                                         ce = nce;
 188                                 i++;
 189                         }
 190                         /*
 191                          * Compensate for loop update
 192                          */
 193                         i--;
 194
 195                         if (revs->combine_merges && num_compare_stages == 2) {
 196                                 show_combined_diff(dpath, 2, revs);
 197                                 free(dpath);
 198                                 continue;
 199                         }
 200                         FREE_AND_NULL(dpath);
 201
 202                         /*
 203                          * Show the diff for the 'ce' if we found the one
 204                          * from the desired stage.
 205                          */
 206                         pair = diff_unmerge(&revs->diffopt, ce->name);
 207                         if (wt_mode)
 208                                 pair->two->mode = wt_mode;
 209                         if (ce_stage(ce) != diff_unmerged_stage)
 210                                 continue;
 211                 }
 212
 213                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
 214                         continue;
 215
 216                 /*
 217                  * When CE_VALID is set (via "update-index --assume-unchanged"
 218                  * or via adding paths while core.ignorestat is set to true),
 219                  * the user has promised that the working tree file for that
 220                  * path will not be modified.  When CE_FSMONITOR_VALID is true,
 221                  * the fsmonitor knows that the path hasn't been modified since
 222                  * we refreshed the cached stat information.  In either case,
 223                  * we do not have to stat to see if the path has been removed
 224                  * or modified.
 225                  */
 226                 if (ce->ce_flags & (CE_VALID | CE_FSMONITOR_VALID)) {
 227                         changed = 0;
 228                         newmode = ce->ce_mode;
 229                 } else {
 230                         struct stat st;
 231
 232                         changed = check_removed(ce, &st);
 233                         if (changed) {
 234                                 if (changed < 0) {
 235                                         perror(ce->name);
 236                                         continue;
 237                                 }
 238                                 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 239                                                &ce->oid,
 240                                                !is_null_oid(&ce->oid),
 241                                                ce->name, 0);
 242                                 continue;
 243                         } else if (revs->diffopt.ita_invisible_in_index &&
 244                                    ce_intent_to_add(ce)) {
 245                                 newmode = ce_mode_from_stat(ce, st.st_mode);
 246                                 diff_addremove(&revs->diffopt, '+', newmode,
 247                                                null_oid(), 0, ce->name, 0);
 248                                 continue;
 249                         }
 250
 251                         changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 252                                                             ce_option, &dirty_submodule);
 253                         newmode = ce_mode_from_stat(ce, st.st_mode);
 254                 }
 255
 256                 if (!changed && !dirty_submodule) {
 257                         ce_mark_uptodate(ce);
 258                         mark_fsmonitor_valid(istate, ce);
 259                         if (!revs->diffopt.flags.find_copies_harder)
 260                                 continue;
 261                 }
 262                 oldmode = ce->ce_mode;
 263                 old_oid = &ce->oid;
 264                 new_oid = changed ? null_oid() : &ce->oid;
 265                 diff_change(&revs->diffopt, oldmode, newmode,
 266                             old_oid, new_oid,
 267                             !is_null_oid(old_oid),
 268                             !is_null_oid(new_oid),
 269                             ce->name, 0, dirty_submodule);
 270
 271         }
 272         diffcore_std(&revs->diffopt);
 273         diff_flush(&revs->diffopt);
 274         trace_performance_since(start, "diff-files");
 275         return 0;
 276 }
 277
 278 /*
 279  * diff-index
 280  */
 281
 282 /* A file entry went away or appeared */
 283 static void diff_index_show_file(struct rev_info *revs,
 284                                  const char *prefix,
 285                                  const struct cache_entry *ce,
 286                                  const struct object_id *oid, int oid_valid,
 287                                  unsigned int mode,
 288                                  unsigned dirty_submodule)
 289 {
 290         diff_addremove(&revs->diffopt, prefix[0], mode,
 291                        oid, oid_valid, ce->name, dirty_submodule);
 292 }
 293
 294 static int get_stat_data(const struct index_state *istate,
 295                          const struct cache_entry *ce,
 296                          const struct object_id **oidp,
 297                          unsigned int *modep,
 298                          int cached, int match_missing,
 299                          unsigned *dirty_submodule, struct diff_options *diffopt)
 300 {
 301         const struct object_id *oid = &ce->oid;
 302         unsigned int mode = ce->ce_mode;
 303
 304         if (!cached && !ce_uptodate(ce)) {
 305                 int changed;
 306                 struct stat st;
 307                 changed = check_removed(ce, &st);
 308                 if (changed < 0)
 309                         return -1;
 310                 else if (changed) {
 311                         if (match_missing) {
 312                                 *oidp = oid;
 313                                 *modep = mode;
 314                                 return 0;
 315                         }
 316                         return -1;
 317                 }
 318                 changed = match_stat_with_submodule(diffopt, ce, &st,
 319                                                     0, dirty_submodule);
 320                 if (changed) {
 321                         mode = ce_mode_from_stat(ce, st.st_mode);
 322                         oid = null_oid();
 323                 }
 324         }
 325
 326         *oidp = oid;
 327         *modep = mode;
 328         return 0;
 329 }
 330
 331 static void show_new_file(struct rev_info *revs,
 332                           const struct cache_entry *new_file,
 333                           int cached, int match_missing)
 334 {
 335         const struct object_id *oid;
 336         unsigned int mode;
 337         unsigned dirty_submodule = 0;
 338         struct index_state *istate = revs->diffopt.repo->index;
 339
 340         if (new_file && S_ISSPARSEDIR(new_file->ce_mode)) {
 341                 diff_tree_oid(NULL, &new_file->oid, new_file->name, &revs->diffopt);
 342                 return;
 343         }
 344
 345         /*
 346          * New file in the index: it might actually be different in
 347          * the working tree.
 348          */
 349         if (get_stat_data(istate, new_file, &oid, &mode, cached, match_missing,
 350             &dirty_submodule, &revs->diffopt) < 0)
 351                 return;
 352
 353         diff_index_show_file(revs, "+", new_file, oid, !is_null_oid(oid), mode, dirty_submodule);
 354 }
 355
 356 static int show_modified(struct rev_info *revs,
 357                          const struct cache_entry *old_entry,
 358                          const struct cache_entry *new_entry,
 359                          int report_missing,
 360                          int cached, int match_missing)
 361 {
 362         unsigned int mode, oldmode;
 363         const struct object_id *oid;
 364         unsigned dirty_submodule = 0;
 365         struct index_state *istate = revs->diffopt.repo->index;
 366
 367         assert(S_ISSPARSEDIR(old_entry->ce_mode) ==
 368                S_ISSPARSEDIR(new_entry->ce_mode));
 369
 370         /*
 371          * If both are sparse directory entries, then expand the
 372          * modifications to the file level. If only one was a sparse
 373          * directory, then they appear as an add and delete instead of
 374          * a modification.
 375          */
 376         if (S_ISSPARSEDIR(new_entry->ce_mode)) {
 377                 diff_tree_oid(&old_entry->oid, &new_entry->oid, new_entry->name, &revs->diffopt);
 378                 return 0;
 379         }
 380
 381         if (get_stat_data(istate, new_entry, &oid, &mode, cached, match_missing,
 382                           &dirty_submodule, &revs->diffopt) < 0) {
 383                 if (report_missing)
 384                         diff_index_show_file(revs, "-", old_entry,
 385                                              &old_entry->oid, 1, old_entry->ce_mode,
 386                                              0);
 387                 return -1;
 388         }
 389
 390         if (revs->combine_merges && !cached &&
 391             (!oideq(oid, &old_entry->oid) || !oideq(&old_entry->oid, &new_entry->oid))) {
 392                 struct combine_diff_path *p;
 393                 int pathlen = ce_namelen(new_entry);
 394
 395                 p = xmalloc(combine_diff_path_size(2, pathlen));
 396                 p->path = (char *) &p->parent[2];
 397                 p->next = NULL;
 398                 memcpy(p->path, new_entry->name, pathlen);
 399                 p->path[pathlen] = 0;
 400                 p->mode = mode;
 401                 oidclr(&p->oid);
 402                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 403                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 404                 p->parent[0].mode = new_entry->ce_mode;
 405                 oidcpy(&p->parent[0].oid, &new_entry->oid);
 406                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 407                 p->parent[1].mode = old_entry->ce_mode;
 408                 oidcpy(&p->parent[1].oid, &old_entry->oid);
 409                 show_combined_diff(p, 2, revs);
 410                 free(p);
 411                 return 0;
 412         }
 413
 414         oldmode = old_entry->ce_mode;
 415         if (mode == oldmode && oideq(oid, &old_entry->oid) && !dirty_submodule &&
 416             !revs->diffopt.flags.find_copies_harder)
 417                 return 0;
 418
 419         diff_change(&revs->diffopt, oldmode, mode,
 420                     &old_entry->oid, oid, 1, !is_null_oid(oid),
 421                     old_entry->name, 0, dirty_submodule);
 422         return 0;
 423 }
 424
 425 /*
 426  * This gets a mix of an existing index and a tree, one pathname entry
 427  * at a time. The index entry may be a single stage-0 one, but it could
 428  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 429  * give you the position and number of entries in the index).
 430  */
 431 static void do_oneway_diff(struct unpack_trees_options *o,
 432                            const struct cache_entry *idx,
 433                            const struct cache_entry *tree)
 434 {
 435         struct rev_info *revs = o->unpack_data;
 436         int match_missing, cached;
 437
 438         /*
 439          * i-t-a entries do not actually exist in the index (if we're
 440          * looking at its content)
 441          */
 442         if (o->index_only &&
 443             revs->diffopt.ita_invisible_in_index &&
 444             idx && ce_intent_to_add(idx)) {
 445                 idx = NULL;
 446                 if (!tree)
 447                         return; /* nothing to diff.. */
 448         }
 449
 450         /* if the entry is not checked out, don't examine work tree */
 451         cached = o->index_only ||
 452                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 453
 454         match_missing = revs->match_missing;
 455
 456         if (cached && idx && ce_stage(idx)) {
 457                 struct diff_filepair *pair;
 458                 pair = diff_unmerge(&revs->diffopt, idx->name);
 459                 if (tree)
 460                         fill_filespec(pair->one, &tree->oid, 1,
 461                                       tree->ce_mode);
 462                 return;
 463         }
 464
 465         /*
 466          * Something added to the tree?
 467          */
 468         if (!tree) {
 469                 show_new_file(revs, idx, cached, match_missing);
 470                 return;
 471         }
 472
 473         /*
 474          * Something removed from the tree?
 475          */
 476         if (!idx) {
 477                 if (S_ISSPARSEDIR(tree->ce_mode)) {
 478                         diff_tree_oid(&tree->oid, NULL, tree->name, &revs->diffopt);
 479                         return;
 480                 }
 481
 482                 diff_index_show_file(revs, "-", tree, &tree->oid, 1,
 483                                      tree->ce_mode, 0);
 484                 return;
 485         }
 486
 487         /* Show difference between old and new */
 488         show_modified(revs, tree, idx, 1, cached, match_missing);
 489 }
 490
 491 /*
 492  * The unpack_trees() interface is designed for merging, so
 493  * the different source entries are designed primarily for
 494  * the source trees, with the old index being really mainly
 495  * used for being replaced by the result.
 496  *
 497  * For diffing, the index is more important, and we only have a
 498  * single tree.
 499  *
 500  * We're supposed to advance o->pos to skip what we have already processed.
 501  *
 502  * This wrapper makes it all more readable, and takes care of all
 503  * the fairly complex unpack_trees() semantic requirements, including
 504  * the skipping, the path matching, the type conflict cases etc.
 505  */
 506 static int oneway_diff(const struct cache_entry * const *src,
 507                        struct unpack_trees_options *o)
 508 {
 509         const struct cache_entry *idx = src[0];
 510         const struct cache_entry *tree = src[1];
 511         struct rev_info *revs = o->unpack_data;
 512
 513         /*
 514          * Unpack-trees generates a DF/conflict entry if
 515          * there was a directory in the index and a tree
 516          * in the tree. From a diff standpoint, that's a
 517          * delete of the tree and a create of the file.
 518          */
 519         if (tree == o->df_conflict_entry)
 520                 tree = NULL;
 521
 522         if (ce_path_match(revs->diffopt.repo->index,
 523                           idx ? idx : tree,
 524                           &revs->prune_data, NULL)) {
 525                 do_oneway_diff(o, idx, tree);
 526                 if (diff_can_quit_early(&revs->diffopt)) {
 527                         o->exiting_early = 1;
 528                         return -1;
 529                 }
 530         }
 531
 532         return 0;
 533 }
 534
 535 static int diff_cache(struct rev_info *revs,
 536                       const struct object_id *tree_oid,
 537                       const char *tree_name,
 538                       int cached)
 539 {
 540         struct tree *tree;
 541         struct tree_desc t;
 542         struct unpack_trees_options opts;
 543
 544         tree = parse_tree_indirect(tree_oid);
 545         if (!tree)
 546                 return error("bad tree object %s",
 547                              tree_name ? tree_name : oid_to_hex(tree_oid));
 548         memset(&opts, 0, sizeof(opts));
 549         opts.head_idx = 1;
 550         opts.index_only = cached;
 551         opts.diff_index_cached = (cached &&
 552                                   !revs->diffopt.flags.find_copies_harder);
 553         opts.merge = 1;
 554         opts.fn = oneway_diff;
 555         opts.unpack_data = revs;
 556         opts.src_index = revs->diffopt.repo->index;
 557         opts.dst_index = NULL;
 558         opts.pathspec = &revs->diffopt.pathspec;
 559         opts.pathspec->recursive = 1;
 560
 561         init_tree_desc(&t, tree->buffer, tree->size);
 562         return unpack_trees(1, &t, &opts);
 563 }
 564
 565 void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
 566 {
 567         int i;
 568         struct commit *mb_child[2] = {0};
 569         struct commit_list *merge_bases;
 570
 571         for (i = 0; i < revs->pending.nr; i++) {
 572                 struct object *obj = revs->pending.objects[i].item;
 573                 if (obj->flags)
 574                         die(_("--merge-base does not work with ranges"));
 575                 if (obj->type != OBJ_COMMIT)
 576                         die(_("--merge-base only works with commits"));
 577         }
 578
 579         /*
 580          * This check must go after the for loop above because A...B
 581          * ranges produce three pending commits, resulting in a
 582          * misleading error message.
 583          */
 584         if (revs->pending.nr < 1 || revs->pending.nr > 2)
 585                 BUG("unexpected revs->pending.nr: %d", revs->pending.nr);
 586
 587         for (i = 0; i < revs->pending.nr; i++)
 588                 mb_child[i] = lookup_commit_reference(the_repository, &revs->pending.objects[i].item->oid);
 589         if (revs->pending.nr == 1) {
 590                 struct object_id oid;
 591
 592                 if (repo_get_oid(the_repository, "HEAD", &oid))
 593                         die(_("unable to get HEAD"));
 594
 595                 mb_child[1] = lookup_commit_reference(the_repository, &oid);
 596         }
 597
 598         merge_bases = repo_get_merge_bases(the_repository, mb_child[0], mb_child[1]);
 599         if (!merge_bases)
 600                 die(_("no merge base found"));
 601         if (merge_bases->next)
 602                 die(_("multiple merge bases found"));
 603
 604         oidcpy(mb, &merge_bases->item->object.oid);
 605
 606         free_commit_list(merge_bases);
 607 }
 608
 609 int run_diff_index(struct rev_info *revs, unsigned int option)
 610 {
 611         struct object_array_entry *ent;
 612         int cached = !!(option & DIFF_INDEX_CACHED);
 613         int merge_base = !!(option & DIFF_INDEX_MERGE_BASE);
 614         struct object_id oid;
 615         const char *name;
 616         char merge_base_hex[GIT_MAX_HEXSZ + 1];
 617         struct index_state *istate = revs->diffopt.repo->index;
 618
 619         if (revs->pending.nr != 1)
 620                 BUG("run_diff_index must be passed exactly one tree");
 621
 622         trace_performance_enter();
 623         ent = revs->pending.objects;
 624
 625         refresh_fsmonitor(istate);
 626
 627         if (merge_base) {
 628                 diff_get_merge_base(revs, &oid);
 629                 name = oid_to_hex_r(merge_base_hex, &oid);
 630         } else {
 631                 oidcpy(&oid, &ent->item->oid);
 632                 name = ent->name;
 633         }
 634
 635         if (diff_cache(revs, &oid, name, cached))
 636                 exit(128);
 637
 638         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 639         diffcore_fix_diff_index();
 640         diffcore_std(&revs->diffopt);
 641         diff_flush(&revs->diffopt);
 642         trace_performance_leave("diff-index");
 643         return 0;
 644 }
 645
 646 int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
 647 {
 648         struct rev_info revs;
 649
 650         repo_init_revisions(opt->repo, &revs, NULL);
 651         copy_pathspec(&revs.prune_data, &opt->pathspec);
 652         diff_setup_done(&revs.diffopt);
 653         revs.diffopt = *opt;
 654
 655         if (diff_cache(&revs, tree_oid, NULL, 1))
 656                 exit(128);
 657         release_revisions(&revs);
 658         return 0;
 659 }
 660
 661 int index_differs_from(struct repository *r,
 662                        const char *def, const struct diff_flags *flags,
 663                        int ita_invisible_in_index)
 664 {
 665         struct rev_info rev;
 666         struct setup_revision_opt opt;
 667         unsigned has_changes;
 668
 669         repo_init_revisions(r, &rev, NULL);
 670         memset(&opt, 0, sizeof(opt));
 671         opt.def = def;
 672         setup_revisions(0, NULL, &rev, &opt);
 673         rev.diffopt.flags.quick = 1;
 674         rev.diffopt.flags.exit_with_status = 1;
 675         if (flags) {
 676                 diff_flags_or(&rev.diffopt.flags, flags);
 677                 /*
 678                  * Now that flags are merged, honor override_submodule_config
 679                  * and ignore_submodules from passed flags.
 680                  */
 681                 if (flags->override_submodule_config)
 682                         rev.diffopt.flags.ignore_submodules = flags->ignore_submodules;
 683         }
 684         rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
 685         run_diff_index(&rev, 1);
 686         has_changes = rev.diffopt.flags.has_changes;
 687         release_revisions(&rev);
 688         return (has_changes != 0);
 689 }
 690
 691 static struct strbuf *idiff_prefix_cb(struct diff_options *opt UNUSED, void *data)
 692 {
 693         return data;
 694 }
 695
 696 void show_interdiff(const struct object_id *oid1, const struct object_id *oid2,
 697                     int indent, struct diff_options *diffopt)
 698 {
 699         struct diff_options opts;
 700         struct strbuf prefix = STRBUF_INIT;
 701
 702         memcpy(&opts, diffopt, sizeof(opts));
 703         opts.output_format = DIFF_FORMAT_PATCH;
 704         opts.output_prefix = idiff_prefix_cb;
 705         strbuf_addchars(&prefix, ' ', indent);
 706         opts.output_prefix_data = &prefix;
 707         diff_setup_done(&opts);
 708
 709         diff_tree_oid(oid1, oid2, "", &opts);
 710         diffcore_std(&opts);
 711         diff_flush(&opts);
 712
 713         strbuf_release(&prefix);
 714 }