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
  14 /*
  15  * diff-files
  16  */
  17
  18 /*
  19  * Has the work tree entity been removed?
  20  *
  21  * Return 1 if it was removed from the work tree, 0 if an entity to be
  22  * compared with the cache entry ce still exists (the latter includes
  23  * the case where a directory that is not a submodule repository
  24  * exists for ce that is a submodule -- it is a submodule that is not
  25  * checked out).  Return negative for an error.
  26  */
  27 static int check_removed(const struct cache_entry *ce, struct stat *st)
  28 {
  29         if (lstat(ce->name, st) < 0) {
  30                 if (errno != ENOENT && errno != ENOTDIR)
  31                         return -1;
  32                 return 1;
  33         }
  34         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  35                 return 1;
  36         if (S_ISDIR(st->st_mode)) {
  37                 unsigned char sub[20];
  38
  39                 /*
  40                  * If ce is already a gitlink, we can have a plain
  41                  * directory (i.e. the submodule is not checked out),
  42                  * or a checked out submodule.  Either case this is not
  43                  * a case where something was removed from the work tree,
  44                  * so we will return 0.
  45                  *
  46                  * Otherwise, if the directory is not a submodule
  47                  * repository, that means ce which was a blob turned into
  48                  * a directory --- the blob was removed!
  49                  */
  50                 if (!S_ISGITLINK(ce->ce_mode) &&
  51                     resolve_gitlink_ref(ce->name, "HEAD", sub))
  52                         return 1;
  53         }
  54         return 0;
  55 }
  56
  57 int run_diff_files(struct rev_info *revs, unsigned int option)
  58 {
  59         int entries, i;
  60         int diff_unmerged_stage = revs->max_count;
  61         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
  62         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
  63                               ? CE_MATCH_RACY_IS_DIRTY : 0);
  64
  65         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
  66
  67         if (diff_unmerged_stage < 0)
  68                 diff_unmerged_stage = 2;
  69         entries = active_nr;
  70         for (i = 0; i < entries; i++) {
  71                 struct stat st;
  72                 unsigned int oldmode, newmode;
  73                 struct cache_entry *ce = active_cache[i];
  74                 int changed;
  75
  76                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
  77                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
  78                         break;
  79
  80                 if (!ce_path_match(ce, revs->prune_data))
  81                         continue;
  82
  83                 if (ce_stage(ce)) {
  84                         struct combine_diff_path *dpath;
  85                         int num_compare_stages = 0;
  86                         size_t path_len;
  87
  88                         path_len = ce_namelen(ce);
  89
  90                         dpath = xmalloc(combine_diff_path_size(5, path_len));
  91                         dpath->path = (char *) &(dpath->parent[5]);
  92
  93                         dpath->next = NULL;
  94                         dpath->len = path_len;
  95                         memcpy(dpath->path, ce->name, path_len);
  96                         dpath->path[path_len] = '\0';
  97                         hashclr(dpath->sha1);
  98                         memset(&(dpath->parent[0]), 0,
  99                                sizeof(struct combine_diff_parent)*5);
 100
 101                         changed = check_removed(ce, &st);
 102                         if (!changed)
 103                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
 104                         else {
 105                                 if (changed < 0) {
 106                                         perror(ce->name);
 107                                         continue;
 108                                 }
 109                                 if (silent_on_removed)
 110                                         continue;
 111                         }
 112
 113                         while (i < entries) {
 114                                 struct cache_entry *nce = active_cache[i];
 115                                 int stage;
 116
 117                                 if (strcmp(ce->name, nce->name))
 118                                         break;
 119
 120                                 /* Stage #2 (ours) is the first parent,
 121                                  * stage #3 (theirs) is the second.
 122                                  */
 123                                 stage = ce_stage(nce);
 124                                 if (2 <= stage) {
 125                                         int mode = nce->ce_mode;
 126                                         num_compare_stages++;
 127                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 128                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 129                                         dpath->parent[stage-2].status =
 130                                                 DIFF_STATUS_MODIFIED;
 131                                 }
 132
 133                                 /* diff against the proper unmerged stage */
 134                                 if (stage == diff_unmerged_stage)
 135                                         ce = nce;
 136                                 i++;
 137                         }
 138                         /*
 139                          * Compensate for loop update
 140                          */
 141                         i--;
 142
 143                         if (revs->combine_merges && num_compare_stages == 2) {
 144                                 show_combined_diff(dpath, 2,
 145                                                    revs->dense_combined_merges,
 146                                                    revs);
 147                                 free(dpath);
 148                                 continue;
 149                         }
 150                         free(dpath);
 151                         dpath = NULL;
 152
 153                         /*
 154                          * Show the diff for the 'ce' if we found the one
 155                          * from the desired stage.
 156                          */
 157                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 158                         if (ce_stage(ce) != diff_unmerged_stage)
 159                                 continue;
 160                 }
 161
 162                 if (ce_uptodate(ce))
 163                         continue;
 164
 165                 changed = check_removed(ce, &st);
 166                 if (changed) {
 167                         if (changed < 0) {
 168                                 perror(ce->name);
 169                                 continue;
 170                         }
 171                         if (silent_on_removed)
 172                                 continue;
 173                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 174                                        ce->sha1, ce->name);
 175                         continue;
 176                 }
 177                 changed = ce_match_stat(ce, &st, ce_option);
 178                 if (!changed) {
 179                         ce_mark_uptodate(ce);
 180                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 181                                 continue;
 182                 }
 183                 oldmode = ce->ce_mode;
 184                 newmode = ce_mode_from_stat(ce, st.st_mode);
 185                 diff_change(&revs->diffopt, oldmode, newmode,
 186                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 187                             ce->name);
 188
 189         }
 190         diffcore_std(&revs->diffopt);
 191         diff_flush(&revs->diffopt);
 192         return 0;
 193 }
 194
 195 /*
 196  * diff-index
 197  */
 198
 199 /* A file entry went away or appeared */
 200 static void diff_index_show_file(struct rev_info *revs,
 201                                  const char *prefix,
 202                                  struct cache_entry *ce,
 203                                  const unsigned char *sha1, unsigned int mode)
 204 {
 205         diff_addremove(&revs->diffopt, prefix[0], mode,
 206                        sha1, ce->name);
 207 }
 208
 209 static int get_stat_data(struct cache_entry *ce,
 210                          const unsigned char **sha1p,
 211                          unsigned int *modep,
 212                          int cached, int match_missing)
 213 {
 214         const unsigned char *sha1 = ce->sha1;
 215         unsigned int mode = ce->ce_mode;
 216
 217         if (!cached && !ce_uptodate(ce)) {
 218                 int changed;
 219                 struct stat st;
 220                 changed = check_removed(ce, &st);
 221                 if (changed < 0)
 222                         return -1;
 223                 else if (changed) {
 224                         if (match_missing) {
 225                                 *sha1p = sha1;
 226                                 *modep = mode;
 227                                 return 0;
 228                         }
 229                         return -1;
 230                 }
 231                 changed = ce_match_stat(ce, &st, 0);
 232                 if (changed) {
 233                         mode = ce_mode_from_stat(ce, st.st_mode);
 234                         sha1 = null_sha1;
 235                 }
 236         }
 237
 238         *sha1p = sha1;
 239         *modep = mode;
 240         return 0;
 241 }
 242
 243 static void show_new_file(struct rev_info *revs,
 244                           struct cache_entry *new,
 245                           int cached, int match_missing)
 246 {
 247         const unsigned char *sha1;
 248         unsigned int mode;
 249
 250         /*
 251          * New file in the index: it might actually be different in
 252          * the working copy.
 253          */
 254         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 255                 return;
 256
 257         diff_index_show_file(revs, "+", new, sha1, mode);
 258 }
 259
 260 static int show_modified(struct rev_info *revs,
 261                          struct cache_entry *old,
 262                          struct cache_entry *new,
 263                          int report_missing,
 264                          int cached, int match_missing)
 265 {
 266         unsigned int mode, oldmode;
 267         const unsigned char *sha1;
 268
 269         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 270                 if (report_missing)
 271                         diff_index_show_file(revs, "-", old,
 272                                              old->sha1, old->ce_mode);
 273                 return -1;
 274         }
 275
 276         if (revs->combine_merges && !cached &&
 277             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 278                 struct combine_diff_path *p;
 279                 int pathlen = ce_namelen(new);
 280
 281                 p = xmalloc(combine_diff_path_size(2, pathlen));
 282                 p->path = (char *) &p->parent[2];
 283                 p->next = NULL;
 284                 p->len = pathlen;
 285                 memcpy(p->path, new->name, pathlen);
 286                 p->path[pathlen] = 0;
 287                 p->mode = mode;
 288                 hashclr(p->sha1);
 289                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 290                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 291                 p->parent[0].mode = new->ce_mode;
 292                 hashcpy(p->parent[0].sha1, new->sha1);
 293                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 294                 p->parent[1].mode = old->ce_mode;
 295                 hashcpy(p->parent[1].sha1, old->sha1);
 296                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 297                 free(p);
 298                 return 0;
 299         }
 300
 301         oldmode = old->ce_mode;
 302         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 303             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 304                 return 0;
 305
 306         diff_change(&revs->diffopt, oldmode, mode,
 307                     old->sha1, sha1, old->name);
 308         return 0;
 309 }
 310
 311 /*
 312  * This turns all merge entries into "stage 3". That guarantees that
 313  * when we read in the new tree (into "stage 1"), we won't lose sight
 314  * of the fact that we had unmerged entries.
 315  */
 316 static void mark_merge_entries(void)
 317 {
 318         int i;
 319         for (i = 0; i < active_nr; i++) {
 320                 struct cache_entry *ce = active_cache[i];
 321                 if (!ce_stage(ce))
 322                         continue;
 323                 ce->ce_flags |= CE_STAGEMASK;
 324         }
 325 }
 326
 327 /*
 328  * This gets a mix of an existing index and a tree, one pathname entry
 329  * at a time. The index entry may be a single stage-0 one, but it could
 330  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 331  * give you the position and number of entries in the index).
 332  */
 333 static void do_oneway_diff(struct unpack_trees_options *o,
 334         struct cache_entry *idx,
 335         struct cache_entry *tree)
 336 {
 337         struct rev_info *revs = o->unpack_data;
 338         int match_missing, cached;
 339
 340         /*
 341          * Backward compatibility wart - "diff-index -m" does
 342          * not mean "do not ignore merges", but "match_missing".
 343          *
 344          * But with the revision flag parsing, that's found in
 345          * "!revs->ignore_merges".
 346          */
 347         cached = o->index_only;
 348         match_missing = !revs->ignore_merges;
 349
 350         if (cached && idx && ce_stage(idx)) {
 351                 if (tree)
 352                         diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
 353                 return;
 354         }
 355
 356         /*
 357          * Something added to the tree?
 358          */
 359         if (!tree) {
 360                 show_new_file(revs, idx, cached, match_missing);
 361                 return;
 362         }
 363
 364         /*
 365          * Something removed from the tree?
 366          */
 367         if (!idx) {
 368                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
 369                 return;
 370         }
 371
 372         /* Show difference between old and new */
 373         show_modified(revs, tree, idx, 1, cached, match_missing);
 374 }
 375
 376 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
 377 {
 378         int len = ce_namelen(ce);
 379         const struct index_state *index = o->src_index;
 380
 381         while (o->pos < index->cache_nr) {
 382                 struct cache_entry *next = index->cache[o->pos];
 383                 if (len != ce_namelen(next))
 384                         break;
 385                 if (memcmp(ce->name, next->name, len))
 386                         break;
 387                 o->pos++;
 388         }
 389 }
 390
 391 /*
 392  * The unpack_trees() interface is designed for merging, so
 393  * the different source entries are designed primarily for
 394  * the source trees, with the old index being really mainly
 395  * used for being replaced by the result.
 396  *
 397  * For diffing, the index is more important, and we only have a
 398  * single tree.
 399  *
 400  * We're supposed to return how many index entries we want to skip.
 401  *
 402  * This wrapper makes it all more readable, and takes care of all
 403  * the fairly complex unpack_trees() semantic requirements, including
 404  * the skipping, the path matching, the type conflict cases etc.
 405  */
 406 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
 407 {
 408         struct cache_entry *idx = src[0];
 409         struct cache_entry *tree = src[1];
 410         struct rev_info *revs = o->unpack_data;
 411
 412         if (idx && ce_stage(idx))
 413                 skip_same_name(idx, o);
 414
 415         /*
 416          * Unpack-trees generates a DF/conflict entry if
 417          * there was a directory in the index and a tree
 418          * in the tree. From a diff standpoint, that's a
 419          * delete of the tree and a create of the file.
 420          */
 421         if (tree == o->df_conflict_entry)
 422                 tree = NULL;
 423
 424         if (ce_path_match(idx ? idx : tree, revs->prune_data))
 425                 do_oneway_diff(o, idx, tree);
 426
 427         return 0;
 428 }
 429
 430 int run_diff_index(struct rev_info *revs, int cached)
 431 {
 432         struct object *ent;
 433         struct tree *tree;
 434         const char *tree_name;
 435         struct unpack_trees_options opts;
 436         struct tree_desc t;
 437
 438         mark_merge_entries();
 439
 440         ent = revs->pending.objects[0].item;
 441         tree_name = revs->pending.objects[0].name;
 442         tree = parse_tree_indirect(ent->sha1);
 443         if (!tree)
 444                 return error("bad tree object %s", tree_name);
 445
 446         memset(&opts, 0, sizeof(opts));
 447         opts.head_idx = 1;
 448         opts.index_only = cached;
 449         opts.diff_index_cached = (cached &&
 450                                   !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
 451         opts.merge = 1;
 452         opts.fn = oneway_diff;
 453         opts.unpack_data = revs;
 454         opts.src_index = &the_index;
 455         opts.dst_index = NULL;
 456
 457         init_tree_desc(&t, tree->buffer, tree->size);
 458         if (unpack_trees(1, &t, &opts))
 459                 exit(128);
 460
 461         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 462         diffcore_std(&revs->diffopt);
 463         diff_flush(&revs->diffopt);
 464         return 0;
 465 }
 466
 467 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 468 {
 469         struct tree *tree;
 470         struct rev_info revs;
 471         int i;
 472         struct cache_entry **dst;
 473         struct cache_entry *last = NULL;
 474         struct unpack_trees_options opts;
 475         struct tree_desc t;
 476
 477         /*
 478          * This is used by git-blame to run diff-cache internally;
 479          * it potentially needs to repeatedly run this, so we will
 480          * start by removing the higher order entries the last round
 481          * left behind.
 482          */
 483         dst = active_cache;
 484         for (i = 0; i < active_nr; i++) {
 485                 struct cache_entry *ce = active_cache[i];
 486                 if (ce_stage(ce)) {
 487                         if (last && !strcmp(ce->name, last->name))
 488                                 continue;
 489                         cache_tree_invalidate_path(active_cache_tree,
 490                                                    ce->name);
 491                         last = ce;
 492                         ce->ce_flags |= CE_REMOVE;
 493                 }
 494                 *dst++ = ce;
 495         }
 496         active_nr = dst - active_cache;
 497
 498         init_revisions(&revs, NULL);
 499         revs.prune_data = opt->paths;
 500         tree = parse_tree_indirect(tree_sha1);
 501         if (!tree)
 502                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 503
 504         memset(&opts, 0, sizeof(opts));
 505         opts.head_idx = 1;
 506         opts.index_only = 1;
 507         opts.diff_index_cached = !DIFF_OPT_TST(opt, FIND_COPIES_HARDER);
 508         opts.merge = 1;
 509         opts.fn = oneway_diff;
 510         opts.unpack_data = &revs;
 511         opts.src_index = &the_index;
 512         opts.dst_index = &the_index;
 513
 514         init_tree_desc(&t, tree->buffer, tree->size);
 515         if (unpack_trees(1, &t, &opts))
 516                 exit(128);
 517         return 0;
 518 }
 519
 520 int index_differs_from(const char *def, int diff_flags)
 521 {
 522         struct rev_info rev;
 523
 524         init_revisions(&rev, NULL);
 525         setup_revisions(0, NULL, &rev, def);
 526         DIFF_OPT_SET(&rev.diffopt, QUIET);
 527         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 528         rev.diffopt.flags |= diff_flags;
 529         run_diff_index(&rev, 1);
 530         if (rev.pending.alloc)
 531                 free(rev.pending.objects);
 532         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
 533 }