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_namelen(ce), ce->name))
  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         char symcache[PATH_MAX];
  65
  66         if (diff_unmerged_stage < 0)
  67                 diff_unmerged_stage = 2;
  68         entries = active_nr;
  69         symcache[0] = '\0';
  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 struct oneway_unpack_data {
 200         struct rev_info *revs;
 201         char symcache[PATH_MAX];
 202 };
 203
 204 /* A file entry went away or appeared */
 205 static void diff_index_show_file(struct rev_info *revs,
 206                                  const char *prefix,
 207                                  struct cache_entry *ce,
 208                                  const unsigned char *sha1, unsigned int mode)
 209 {
 210         diff_addremove(&revs->diffopt, prefix[0], mode,
 211                        sha1, ce->name);
 212 }
 213
 214 static int get_stat_data(struct cache_entry *ce,
 215                          const unsigned char **sha1p,
 216                          unsigned int *modep,
 217                          int cached, int match_missing,
 218                          struct oneway_unpack_data *cbdata)
 219 {
 220         const unsigned char *sha1 = ce->sha1;
 221         unsigned int mode = ce->ce_mode;
 222
 223         if (!cached) {
 224                 int changed;
 225                 struct stat st;
 226                 changed = check_removed(ce, &st);
 227                 if (changed < 0)
 228                         return -1;
 229                 else if (changed) {
 230                         if (match_missing) {
 231                                 *sha1p = sha1;
 232                                 *modep = mode;
 233                                 return 0;
 234                         }
 235                         return -1;
 236                 }
 237                 changed = ce_match_stat(ce, &st, 0);
 238                 if (changed) {
 239                         mode = ce_mode_from_stat(ce, st.st_mode);
 240                         sha1 = null_sha1;
 241                 }
 242         }
 243
 244         *sha1p = sha1;
 245         *modep = mode;
 246         return 0;
 247 }
 248
 249 static void show_new_file(struct oneway_unpack_data *cbdata,
 250                           struct cache_entry *new,
 251                           int cached, int match_missing)
 252 {
 253         const unsigned char *sha1;
 254         unsigned int mode;
 255         struct rev_info *revs = cbdata->revs;
 256
 257         /*
 258          * New file in the index: it might actually be different in
 259          * the working copy.
 260          */
 261         if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0)
 262                 return;
 263
 264         diff_index_show_file(revs, "+", new, sha1, mode);
 265 }
 266
 267 static int show_modified(struct oneway_unpack_data *cbdata,
 268                          struct cache_entry *old,
 269                          struct cache_entry *new,
 270                          int report_missing,
 271                          int cached, int match_missing)
 272 {
 273         unsigned int mode, oldmode;
 274         const unsigned char *sha1;
 275         struct rev_info *revs = cbdata->revs;
 276
 277         if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0) {
 278                 if (report_missing)
 279                         diff_index_show_file(revs, "-", old,
 280                                              old->sha1, old->ce_mode);
 281                 return -1;
 282         }
 283
 284         if (revs->combine_merges && !cached &&
 285             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 286                 struct combine_diff_path *p;
 287                 int pathlen = ce_namelen(new);
 288
 289                 p = xmalloc(combine_diff_path_size(2, pathlen));
 290                 p->path = (char *) &p->parent[2];
 291                 p->next = NULL;
 292                 p->len = pathlen;
 293                 memcpy(p->path, new->name, pathlen);
 294                 p->path[pathlen] = 0;
 295                 p->mode = mode;
 296                 hashclr(p->sha1);
 297                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 298                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 299                 p->parent[0].mode = new->ce_mode;
 300                 hashcpy(p->parent[0].sha1, new->sha1);
 301                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 302                 p->parent[1].mode = old->ce_mode;
 303                 hashcpy(p->parent[1].sha1, old->sha1);
 304                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 305                 free(p);
 306                 return 0;
 307         }
 308
 309         oldmode = old->ce_mode;
 310         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 311             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 312                 return 0;
 313
 314         diff_change(&revs->diffopt, oldmode, mode,
 315                     old->sha1, sha1, old->name);
 316         return 0;
 317 }
 318
 319 /*
 320  * This turns all merge entries into "stage 3". That guarantees that
 321  * when we read in the new tree (into "stage 1"), we won't lose sight
 322  * of the fact that we had unmerged entries.
 323  */
 324 static void mark_merge_entries(void)
 325 {
 326         int i;
 327         for (i = 0; i < active_nr; i++) {
 328                 struct cache_entry *ce = active_cache[i];
 329                 if (!ce_stage(ce))
 330                         continue;
 331                 ce->ce_flags |= CE_STAGEMASK;
 332         }
 333 }
 334
 335 /*
 336  * This gets a mix of an existing index and a tree, one pathname entry
 337  * at a time. The index entry may be a single stage-0 one, but it could
 338  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 339  * give you the position and number of entries in the index).
 340  */
 341 static void do_oneway_diff(struct unpack_trees_options *o,
 342         struct cache_entry *idx,
 343         struct cache_entry *tree)
 344 {
 345         struct oneway_unpack_data *cbdata = o->unpack_data;
 346         struct rev_info *revs = cbdata->revs;
 347         int match_missing, cached;
 348
 349         /*
 350          * Backward compatibility wart - "diff-index -m" does
 351          * not mean "do not ignore merges", but "match_missing".
 352          *
 353          * But with the revision flag parsing, that's found in
 354          * "!revs->ignore_merges".
 355          */
 356         cached = o->index_only;
 357         match_missing = !revs->ignore_merges;
 358
 359         if (cached && idx && ce_stage(idx)) {
 360                 if (tree)
 361                         diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
 362                 return;
 363         }
 364
 365         /*
 366          * Something added to the tree?
 367          */
 368         if (!tree) {
 369                 show_new_file(cbdata, idx, cached, match_missing);
 370                 return;
 371         }
 372
 373         /*
 374          * Something removed from the tree?
 375          */
 376         if (!idx) {
 377                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
 378                 return;
 379         }
 380
 381         /* Show difference between old and new */
 382         show_modified(cbdata, tree, idx, 1, cached, match_missing);
 383 }
 384
 385 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
 386 {
 387         int len = ce_namelen(ce);
 388         const struct index_state *index = o->src_index;
 389
 390         while (o->pos < index->cache_nr) {
 391                 struct cache_entry *next = index->cache[o->pos];
 392                 if (len != ce_namelen(next))
 393                         break;
 394                 if (memcmp(ce->name, next->name, len))
 395                         break;
 396                 o->pos++;
 397         }
 398 }
 399
 400 /*
 401  * The unpack_trees() interface is designed for merging, so
 402  * the different source entries are designed primarily for
 403  * the source trees, with the old index being really mainly
 404  * used for being replaced by the result.
 405  *
 406  * For diffing, the index is more important, and we only have a
 407  * single tree.
 408  *
 409  * We're supposed to return how many index entries we want to skip.
 410  *
 411  * This wrapper makes it all more readable, and takes care of all
 412  * the fairly complex unpack_trees() semantic requirements, including
 413  * the skipping, the path matching, the type conflict cases etc.
 414  */
 415 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
 416 {
 417         struct cache_entry *idx = src[0];
 418         struct cache_entry *tree = src[1];
 419         struct oneway_unpack_data *cbdata = o->unpack_data;
 420         struct rev_info *revs = cbdata->revs;
 421
 422         if (idx && ce_stage(idx))
 423                 skip_same_name(idx, o);
 424
 425         /*
 426          * Unpack-trees generates a DF/conflict entry if
 427          * there was a directory in the index and a tree
 428          * in the tree. From a diff standpoint, that's a
 429          * delete of the tree and a create of the file.
 430          */
 431         if (tree == o->df_conflict_entry)
 432                 tree = NULL;
 433
 434         if (ce_path_match(idx ? idx : tree, revs->prune_data))
 435                 do_oneway_diff(o, idx, tree);
 436
 437         return 0;
 438 }
 439
 440 int run_diff_index(struct rev_info *revs, int cached)
 441 {
 442         struct object *ent;
 443         struct tree *tree;
 444         const char *tree_name;
 445         struct unpack_trees_options opts;
 446         struct tree_desc t;
 447         struct oneway_unpack_data unpack_cb;
 448
 449         mark_merge_entries();
 450
 451         ent = revs->pending.objects[0].item;
 452         tree_name = revs->pending.objects[0].name;
 453         tree = parse_tree_indirect(ent->sha1);
 454         if (!tree)
 455                 return error("bad tree object %s", tree_name);
 456
 457         unpack_cb.revs = revs;
 458         unpack_cb.symcache[0] = '\0';
 459         memset(&opts, 0, sizeof(opts));
 460         opts.head_idx = 1;
 461         opts.index_only = cached;
 462         opts.merge = 1;
 463         opts.fn = oneway_diff;
 464         opts.unpack_data = &unpack_cb;
 465         opts.src_index = &the_index;
 466         opts.dst_index = NULL;
 467
 468         init_tree_desc(&t, tree->buffer, tree->size);
 469         if (unpack_trees(1, &t, &opts))
 470                 exit(128);
 471
 472         diffcore_std(&revs->diffopt);
 473         diff_flush(&revs->diffopt);
 474         return 0;
 475 }
 476
 477 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 478 {
 479         struct tree *tree;
 480         struct rev_info revs;
 481         int i;
 482         struct cache_entry **dst;
 483         struct cache_entry *last = NULL;
 484         struct unpack_trees_options opts;
 485         struct tree_desc t;
 486         struct oneway_unpack_data unpack_cb;
 487
 488         /*
 489          * This is used by git-blame to run diff-cache internally;
 490          * it potentially needs to repeatedly run this, so we will
 491          * start by removing the higher order entries the last round
 492          * left behind.
 493          */
 494         dst = active_cache;
 495         for (i = 0; i < active_nr; i++) {
 496                 struct cache_entry *ce = active_cache[i];
 497                 if (ce_stage(ce)) {
 498                         if (last && !strcmp(ce->name, last->name))
 499                                 continue;
 500                         cache_tree_invalidate_path(active_cache_tree,
 501                                                    ce->name);
 502                         last = ce;
 503                         ce->ce_flags |= CE_REMOVE;
 504                 }
 505                 *dst++ = ce;
 506         }
 507         active_nr = dst - active_cache;
 508
 509         init_revisions(&revs, NULL);
 510         revs.prune_data = opt->paths;
 511         tree = parse_tree_indirect(tree_sha1);
 512         if (!tree)
 513                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 514
 515         unpack_cb.revs = &revs;
 516         unpack_cb.symcache[0] = '\0';
 517         memset(&opts, 0, sizeof(opts));
 518         opts.head_idx = 1;
 519         opts.index_only = 1;
 520         opts.merge = 1;
 521         opts.fn = oneway_diff;
 522         opts.unpack_data = &unpack_cb;
 523         opts.src_index = &the_index;
 524         opts.dst_index = &the_index;
 525
 526         init_tree_desc(&t, tree->buffer, tree->size);
 527         if (unpack_trees(1, &t, &opts))
 528                 exit(128);
 529         return 0;
 530 }