Merge branch 'js/sideband-stderr'
[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, 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) {
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.merge = 1;
450         opts.fn = oneway_diff;
451         opts.unpack_data = revs;
452         opts.src_index = &the_index;
453         opts.dst_index = NULL;
454
455         init_tree_desc(&t, tree->buffer, tree->size);
456         if (unpack_trees(1, &t, &opts))
457                 exit(128);
458
459         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
460         diffcore_std(&revs->diffopt);
461         diff_flush(&revs->diffopt);
462         return 0;
463 }
464
465 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
466 {
467         struct tree *tree;
468         struct rev_info revs;
469         int i;
470         struct cache_entry **dst;
471         struct cache_entry *last = NULL;
472         struct unpack_trees_options opts;
473         struct tree_desc t;
474
475         /*
476          * This is used by git-blame to run diff-cache internally;
477          * it potentially needs to repeatedly run this, so we will
478          * start by removing the higher order entries the last round
479          * left behind.
480          */
481         dst = active_cache;
482         for (i = 0; i < active_nr; i++) {
483                 struct cache_entry *ce = active_cache[i];
484                 if (ce_stage(ce)) {
485                         if (last && !strcmp(ce->name, last->name))
486                                 continue;
487                         cache_tree_invalidate_path(active_cache_tree,
488                                                    ce->name);
489                         last = ce;
490                         ce->ce_flags |= CE_REMOVE;
491                 }
492                 *dst++ = ce;
493         }
494         active_nr = dst - active_cache;
495
496         init_revisions(&revs, NULL);
497         revs.prune_data = opt->paths;
498         tree = parse_tree_indirect(tree_sha1);
499         if (!tree)
500                 die("bad tree object %s", sha1_to_hex(tree_sha1));
501
502         memset(&opts, 0, sizeof(opts));
503         opts.head_idx = 1;
504         opts.index_only = 1;
505         opts.merge = 1;
506         opts.fn = oneway_diff;
507         opts.unpack_data = &revs;
508         opts.src_index = &the_index;
509         opts.dst_index = &the_index;
510
511         init_tree_desc(&t, tree->buffer, tree->size);
512         if (unpack_trees(1, &t, &opts))
513                 exit(128);
514         return 0;
515 }
516
517 int index_differs_from(const char *def, int diff_flags)
518 {
519         struct rev_info rev;
520
521         init_revisions(&rev, NULL);
522         setup_revisions(0, NULL, &rev, def);
523         DIFF_OPT_SET(&rev.diffopt, QUIET);
524         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
525         rev.diffopt.flags |= diff_flags;
526         run_diff_index(&rev, 1);
527         if (rev.pending.alloc)
528                 free(rev.pending.objects);
529         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
530 }