Merge branch 'mm/conflict-advice'
[git] / 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, QUICK) &&
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) || ce_skip_worktree(ce))
163                         continue;
164
165                 /* If CE_VALID is set, don't look at workdir for file removal */
166                 changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
167                 if (changed) {
168                         if (changed < 0) {
169                                 perror(ce->name);
170                                 continue;
171                         }
172                         if (silent_on_removed)
173                                 continue;
174                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
175                                        ce->sha1, ce->name);
176                         continue;
177                 }
178                 changed = ce_match_stat(ce, &st, ce_option);
179                 if (!changed) {
180                         ce_mark_uptodate(ce);
181                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
182                                 continue;
183                 }
184                 oldmode = ce->ce_mode;
185                 newmode = ce_mode_from_stat(ce, st.st_mode);
186                 diff_change(&revs->diffopt, oldmode, newmode,
187                             ce->sha1, (changed ? null_sha1 : ce->sha1),
188                             ce->name);
189
190         }
191         diffcore_std(&revs->diffopt);
192         diff_flush(&revs->diffopt);
193         return 0;
194 }
195
196 /*
197  * diff-index
198  */
199
200 /* A file entry went away or appeared */
201 static void diff_index_show_file(struct rev_info *revs,
202                                  const char *prefix,
203                                  struct cache_entry *ce,
204                                  const unsigned char *sha1, unsigned int mode)
205 {
206         diff_addremove(&revs->diffopt, prefix[0], mode,
207                        sha1, ce->name);
208 }
209
210 static int get_stat_data(struct cache_entry *ce,
211                          const unsigned char **sha1p,
212                          unsigned int *modep,
213                          int cached, int match_missing)
214 {
215         const unsigned char *sha1 = ce->sha1;
216         unsigned int mode = ce->ce_mode;
217
218         if (!cached && !ce_uptodate(ce)) {
219                 int changed;
220                 struct stat st;
221                 changed = check_removed(ce, &st);
222                 if (changed < 0)
223                         return -1;
224                 else if (changed) {
225                         if (match_missing) {
226                                 *sha1p = sha1;
227                                 *modep = mode;
228                                 return 0;
229                         }
230                         return -1;
231                 }
232                 changed = ce_match_stat(ce, &st, 0);
233                 if (changed) {
234                         mode = ce_mode_from_stat(ce, st.st_mode);
235                         sha1 = null_sha1;
236                 }
237         }
238
239         *sha1p = sha1;
240         *modep = mode;
241         return 0;
242 }
243
244 static void show_new_file(struct rev_info *revs,
245                           struct cache_entry *new,
246                           int cached, int match_missing)
247 {
248         const unsigned char *sha1;
249         unsigned int mode;
250
251         /*
252          * New file in the index: it might actually be different in
253          * the working copy.
254          */
255         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
256                 return;
257
258         diff_index_show_file(revs, "+", new, sha1, mode);
259 }
260
261 static int show_modified(struct rev_info *revs,
262                          struct cache_entry *old,
263                          struct cache_entry *new,
264                          int report_missing,
265                          int cached, int match_missing)
266 {
267         unsigned int mode, oldmode;
268         const unsigned char *sha1;
269
270         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
271                 if (report_missing)
272                         diff_index_show_file(revs, "-", old,
273                                              old->sha1, old->ce_mode);
274                 return -1;
275         }
276
277         if (revs->combine_merges && !cached &&
278             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
279                 struct combine_diff_path *p;
280                 int pathlen = ce_namelen(new);
281
282                 p = xmalloc(combine_diff_path_size(2, pathlen));
283                 p->path = (char *) &p->parent[2];
284                 p->next = NULL;
285                 p->len = pathlen;
286                 memcpy(p->path, new->name, pathlen);
287                 p->path[pathlen] = 0;
288                 p->mode = mode;
289                 hashclr(p->sha1);
290                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
291                 p->parent[0].status = DIFF_STATUS_MODIFIED;
292                 p->parent[0].mode = new->ce_mode;
293                 hashcpy(p->parent[0].sha1, new->sha1);
294                 p->parent[1].status = DIFF_STATUS_MODIFIED;
295                 p->parent[1].mode = old->ce_mode;
296                 hashcpy(p->parent[1].sha1, old->sha1);
297                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
298                 free(p);
299                 return 0;
300         }
301
302         oldmode = old->ce_mode;
303         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
304             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
305                 return 0;
306
307         diff_change(&revs->diffopt, oldmode, mode,
308                     old->sha1, sha1, old->name);
309         return 0;
310 }
311
312 /*
313  * This gets a mix of an existing index and a tree, one pathname entry
314  * at a time. The index entry may be a single stage-0 one, but it could
315  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
316  * give you the position and number of entries in the index).
317  */
318 static void do_oneway_diff(struct unpack_trees_options *o,
319         struct cache_entry *idx,
320         struct cache_entry *tree)
321 {
322         struct rev_info *revs = o->unpack_data;
323         int match_missing, cached;
324
325         /* if the entry is not checked out, don't examine work tree */
326         cached = o->index_only ||
327                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
328         /*
329          * Backward compatibility wart - "diff-index -m" does
330          * not mean "do not ignore merges", but "match_missing".
331          *
332          * But with the revision flag parsing, that's found in
333          * "!revs->ignore_merges".
334          */
335         match_missing = !revs->ignore_merges;
336
337         if (cached && idx && ce_stage(idx)) {
338                 diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode,
339                              idx->sha1);
340                 return;
341         }
342
343         /*
344          * Something added to the tree?
345          */
346         if (!tree) {
347                 show_new_file(revs, idx, cached, match_missing);
348                 return;
349         }
350
351         /*
352          * Something removed from the tree?
353          */
354         if (!idx) {
355                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
356                 return;
357         }
358
359         /* Show difference between old and new */
360         show_modified(revs, tree, idx, 1, cached, match_missing);
361 }
362
363 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
364 {
365         int len = ce_namelen(ce);
366         const struct index_state *index = o->src_index;
367
368         while (o->pos < index->cache_nr) {
369                 struct cache_entry *next = index->cache[o->pos];
370                 if (len != ce_namelen(next))
371                         break;
372                 if (memcmp(ce->name, next->name, len))
373                         break;
374                 o->pos++;
375         }
376 }
377
378 /*
379  * The unpack_trees() interface is designed for merging, so
380  * the different source entries are designed primarily for
381  * the source trees, with the old index being really mainly
382  * used for being replaced by the result.
383  *
384  * For diffing, the index is more important, and we only have a
385  * single tree.
386  *
387  * We're supposed to advance o->pos to skip what we have already processed.
388  *
389  * This wrapper makes it all more readable, and takes care of all
390  * the fairly complex unpack_trees() semantic requirements, including
391  * the skipping, the path matching, the type conflict cases etc.
392  */
393 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
394 {
395         struct cache_entry *idx = src[0];
396         struct cache_entry *tree = src[1];
397         struct rev_info *revs = o->unpack_data;
398
399         if (idx && ce_stage(idx))
400                 skip_same_name(idx, o);
401
402         /*
403          * Unpack-trees generates a DF/conflict entry if
404          * there was a directory in the index and a tree
405          * in the tree. From a diff standpoint, that's a
406          * delete of the tree and a create of the file.
407          */
408         if (tree == o->df_conflict_entry)
409                 tree = NULL;
410
411         if (ce_path_match(idx ? idx : tree, revs->prune_data))
412                 do_oneway_diff(o, idx, tree);
413
414         return 0;
415 }
416
417 int run_diff_index(struct rev_info *revs, int cached)
418 {
419         struct object *ent;
420         struct tree *tree;
421         const char *tree_name;
422         struct unpack_trees_options opts;
423         struct tree_desc t;
424
425         ent = revs->pending.objects[0].item;
426         tree_name = revs->pending.objects[0].name;
427         tree = parse_tree_indirect(ent->sha1);
428         if (!tree)
429                 return error("bad tree object %s", tree_name);
430
431         memset(&opts, 0, sizeof(opts));
432         opts.head_idx = 1;
433         opts.index_only = cached;
434         opts.diff_index_cached = (cached &&
435                                   !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
436         opts.merge = 1;
437         opts.fn = oneway_diff;
438         opts.unpack_data = revs;
439         opts.src_index = &the_index;
440         opts.dst_index = NULL;
441
442         init_tree_desc(&t, tree->buffer, tree->size);
443         if (unpack_trees(1, &t, &opts))
444                 exit(128);
445
446         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
447         diffcore_std(&revs->diffopt);
448         diff_flush(&revs->diffopt);
449         return 0;
450 }
451
452 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
453 {
454         struct tree *tree;
455         struct rev_info revs;
456         int i;
457         struct cache_entry **dst;
458         struct cache_entry *last = NULL;
459         struct unpack_trees_options opts;
460         struct tree_desc t;
461
462         /*
463          * This is used by git-blame to run diff-cache internally;
464          * it potentially needs to repeatedly run this, so we will
465          * start by removing the higher order entries the last round
466          * left behind.
467          */
468         dst = active_cache;
469         for (i = 0; i < active_nr; i++) {
470                 struct cache_entry *ce = active_cache[i];
471                 if (ce_stage(ce)) {
472                         if (last && !strcmp(ce->name, last->name))
473                                 continue;
474                         cache_tree_invalidate_path(active_cache_tree,
475                                                    ce->name);
476                         last = ce;
477                         ce->ce_flags |= CE_REMOVE;
478                 }
479                 *dst++ = ce;
480         }
481         active_nr = dst - active_cache;
482
483         init_revisions(&revs, NULL);
484         revs.prune_data = opt->paths;
485         tree = parse_tree_indirect(tree_sha1);
486         if (!tree)
487                 die("bad tree object %s", sha1_to_hex(tree_sha1));
488
489         memset(&opts, 0, sizeof(opts));
490         opts.head_idx = 1;
491         opts.index_only = 1;
492         opts.diff_index_cached = !DIFF_OPT_TST(opt, FIND_COPIES_HARDER);
493         opts.merge = 1;
494         opts.fn = oneway_diff;
495         opts.unpack_data = &revs;
496         opts.src_index = &the_index;
497         opts.dst_index = &the_index;
498
499         init_tree_desc(&t, tree->buffer, tree->size);
500         if (unpack_trees(1, &t, &opts))
501                 exit(128);
502         return 0;
503 }
504
505 int index_differs_from(const char *def, int diff_flags)
506 {
507         struct rev_info rev;
508
509         init_revisions(&rev, NULL);
510         setup_revisions(0, NULL, &rev, def);
511         DIFF_OPT_SET(&rev.diffopt, QUICK);
512         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
513         rev.diffopt.flags |= diff_flags;
514         run_diff_index(&rev, 1);
515         if (rev.pending.alloc)
516                 free(rev.pending.objects);
517         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
518 }