Update draft release notes to 1.7.1.1
[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 #include "submodule.h"
14
15 /*
16  * diff-files
17  */
18
19 /*
20  * Has the work tree entity been removed?
21  *
22  * Return 1 if it was removed from the work tree, 0 if an entity to be
23  * compared with the cache entry ce still exists (the latter includes
24  * the case where a directory that is not a submodule repository
25  * exists for ce that is a submodule -- it is a submodule that is not
26  * checked out).  Return negative for an error.
27  */
28 static int check_removed(const struct cache_entry *ce, struct stat *st)
29 {
30         if (lstat(ce->name, st) < 0) {
31                 if (errno != ENOENT && errno != ENOTDIR)
32                         return -1;
33                 return 1;
34         }
35         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
36                 return 1;
37         if (S_ISDIR(st->st_mode)) {
38                 unsigned char sub[20];
39
40                 /*
41                  * If ce is already a gitlink, we can have a plain
42                  * directory (i.e. the submodule is not checked out),
43                  * or a checked out submodule.  Either case this is not
44                  * a case where something was removed from the work tree,
45                  * so we will return 0.
46                  *
47                  * Otherwise, if the directory is not a submodule
48                  * repository, that means ce which was a blob turned into
49                  * a directory --- the blob was removed!
50                  */
51                 if (!S_ISGITLINK(ce->ce_mode) &&
52                     resolve_gitlink_ref(ce->name, "HEAD", sub))
53                         return 1;
54         }
55         return 0;
56 }
57
58 /*
59  * Has a file changed or has a submodule new commits or a dirty work tree?
60  *
61  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
62  * option is set, the caller does not only want to know if a submodule is
63  * modified at all but wants to know all the conditions that are met (new
64  * commits, untracked content and/or modified content).
65  */
66 static int match_stat_with_submodule(struct diff_options *diffopt,
67                                       struct cache_entry *ce, struct stat *st,
68                                       unsigned ce_option, unsigned *dirty_submodule)
69 {
70         int changed = ce_match_stat(ce, st, ce_option);
71         if (S_ISGITLINK(ce->ce_mode)
72             && !DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES)
73             && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES))) {
74                 *dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
75         }
76         return changed;
77 }
78
79 int run_diff_files(struct rev_info *revs, unsigned int option)
80 {
81         int entries, i;
82         int diff_unmerged_stage = revs->max_count;
83         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
84         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
85                               ? CE_MATCH_RACY_IS_DIRTY : 0);
86
87         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
88
89         if (diff_unmerged_stage < 0)
90                 diff_unmerged_stage = 2;
91         entries = active_nr;
92         for (i = 0; i < entries; i++) {
93                 struct stat st;
94                 unsigned int oldmode, newmode;
95                 struct cache_entry *ce = active_cache[i];
96                 int changed;
97                 unsigned dirty_submodule = 0;
98
99                 if (DIFF_OPT_TST(&revs->diffopt, QUICK) &&
100                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
101                         break;
102
103                 if (!ce_path_match(ce, revs->prune_data))
104                         continue;
105
106                 if (ce_stage(ce)) {
107                         struct combine_diff_path *dpath;
108                         int num_compare_stages = 0;
109                         size_t path_len;
110
111                         path_len = ce_namelen(ce);
112
113                         dpath = xmalloc(combine_diff_path_size(5, path_len));
114                         dpath->path = (char *) &(dpath->parent[5]);
115
116                         dpath->next = NULL;
117                         dpath->len = path_len;
118                         memcpy(dpath->path, ce->name, path_len);
119                         dpath->path[path_len] = '\0';
120                         hashclr(dpath->sha1);
121                         memset(&(dpath->parent[0]), 0,
122                                sizeof(struct combine_diff_parent)*5);
123
124                         changed = check_removed(ce, &st);
125                         if (!changed)
126                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
127                         else {
128                                 if (changed < 0) {
129                                         perror(ce->name);
130                                         continue;
131                                 }
132                                 if (silent_on_removed)
133                                         continue;
134                         }
135
136                         while (i < entries) {
137                                 struct cache_entry *nce = active_cache[i];
138                                 int stage;
139
140                                 if (strcmp(ce->name, nce->name))
141                                         break;
142
143                                 /* Stage #2 (ours) is the first parent,
144                                  * stage #3 (theirs) is the second.
145                                  */
146                                 stage = ce_stage(nce);
147                                 if (2 <= stage) {
148                                         int mode = nce->ce_mode;
149                                         num_compare_stages++;
150                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
151                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
152                                         dpath->parent[stage-2].status =
153                                                 DIFF_STATUS_MODIFIED;
154                                 }
155
156                                 /* diff against the proper unmerged stage */
157                                 if (stage == diff_unmerged_stage)
158                                         ce = nce;
159                                 i++;
160                         }
161                         /*
162                          * Compensate for loop update
163                          */
164                         i--;
165
166                         if (revs->combine_merges && num_compare_stages == 2) {
167                                 show_combined_diff(dpath, 2,
168                                                    revs->dense_combined_merges,
169                                                    revs);
170                                 free(dpath);
171                                 continue;
172                         }
173                         free(dpath);
174                         dpath = NULL;
175
176                         /*
177                          * Show the diff for the 'ce' if we found the one
178                          * from the desired stage.
179                          */
180                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
181                         if (ce_stage(ce) != diff_unmerged_stage)
182                                 continue;
183                 }
184
185                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
186                         continue;
187
188                 /* If CE_VALID is set, don't look at workdir for file removal */
189                 changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
190                 if (changed) {
191                         if (changed < 0) {
192                                 perror(ce->name);
193                                 continue;
194                         }
195                         if (silent_on_removed)
196                                 continue;
197                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
198                                        ce->sha1, ce->name, 0);
199                         continue;
200                 }
201                 changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
202                                                     ce_option, &dirty_submodule);
203                 if (!changed && !dirty_submodule) {
204                         ce_mark_uptodate(ce);
205                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
206                                 continue;
207                 }
208                 oldmode = ce->ce_mode;
209                 newmode = ce_mode_from_stat(ce, st.st_mode);
210                 diff_change(&revs->diffopt, oldmode, newmode,
211                             ce->sha1, (changed ? null_sha1 : ce->sha1),
212                             ce->name, 0, dirty_submodule);
213
214         }
215         diffcore_std(&revs->diffopt);
216         diff_flush(&revs->diffopt);
217         return 0;
218 }
219
220 /*
221  * diff-index
222  */
223
224 /* A file entry went away or appeared */
225 static void diff_index_show_file(struct rev_info *revs,
226                                  const char *prefix,
227                                  struct cache_entry *ce,
228                                  const unsigned char *sha1, unsigned int mode,
229                                  unsigned dirty_submodule)
230 {
231         diff_addremove(&revs->diffopt, prefix[0], mode,
232                        sha1, ce->name, dirty_submodule);
233 }
234
235 static int get_stat_data(struct cache_entry *ce,
236                          const unsigned char **sha1p,
237                          unsigned int *modep,
238                          int cached, int match_missing,
239                          unsigned *dirty_submodule, struct diff_options *diffopt)
240 {
241         const unsigned char *sha1 = ce->sha1;
242         unsigned int mode = ce->ce_mode;
243
244         if (!cached && !ce_uptodate(ce)) {
245                 int changed;
246                 struct stat st;
247                 changed = check_removed(ce, &st);
248                 if (changed < 0)
249                         return -1;
250                 else if (changed) {
251                         if (match_missing) {
252                                 *sha1p = sha1;
253                                 *modep = mode;
254                                 return 0;
255                         }
256                         return -1;
257                 }
258                 changed = match_stat_with_submodule(diffopt, ce, &st,
259                                                     0, dirty_submodule);
260                 if (changed) {
261                         mode = ce_mode_from_stat(ce, st.st_mode);
262                         sha1 = null_sha1;
263                 }
264         }
265
266         *sha1p = sha1;
267         *modep = mode;
268         return 0;
269 }
270
271 static void show_new_file(struct rev_info *revs,
272                           struct cache_entry *new,
273                           int cached, int match_missing)
274 {
275         const unsigned char *sha1;
276         unsigned int mode;
277         unsigned dirty_submodule = 0;
278
279         /*
280          * New file in the index: it might actually be different in
281          * the working copy.
282          */
283         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
284             &dirty_submodule, &revs->diffopt) < 0)
285                 return;
286
287         diff_index_show_file(revs, "+", new, sha1, mode, dirty_submodule);
288 }
289
290 static int show_modified(struct rev_info *revs,
291                          struct cache_entry *old,
292                          struct cache_entry *new,
293                          int report_missing,
294                          int cached, int match_missing)
295 {
296         unsigned int mode, oldmode;
297         const unsigned char *sha1;
298         unsigned dirty_submodule = 0;
299
300         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
301                           &dirty_submodule, &revs->diffopt) < 0) {
302                 if (report_missing)
303                         diff_index_show_file(revs, "-", old,
304                                              old->sha1, old->ce_mode, 0);
305                 return -1;
306         }
307
308         if (revs->combine_merges && !cached &&
309             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
310                 struct combine_diff_path *p;
311                 int pathlen = ce_namelen(new);
312
313                 p = xmalloc(combine_diff_path_size(2, pathlen));
314                 p->path = (char *) &p->parent[2];
315                 p->next = NULL;
316                 p->len = pathlen;
317                 memcpy(p->path, new->name, pathlen);
318                 p->path[pathlen] = 0;
319                 p->mode = mode;
320                 hashclr(p->sha1);
321                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
322                 p->parent[0].status = DIFF_STATUS_MODIFIED;
323                 p->parent[0].mode = new->ce_mode;
324                 hashcpy(p->parent[0].sha1, new->sha1);
325                 p->parent[1].status = DIFF_STATUS_MODIFIED;
326                 p->parent[1].mode = old->ce_mode;
327                 hashcpy(p->parent[1].sha1, old->sha1);
328                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
329                 free(p);
330                 return 0;
331         }
332
333         oldmode = old->ce_mode;
334         if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
335             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
336                 return 0;
337
338         diff_change(&revs->diffopt, oldmode, mode,
339                     old->sha1, sha1, old->name, 0, dirty_submodule);
340         return 0;
341 }
342
343 /*
344  * This gets a mix of an existing index and a tree, one pathname entry
345  * at a time. The index entry may be a single stage-0 one, but it could
346  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
347  * give you the position and number of entries in the index).
348  */
349 static void do_oneway_diff(struct unpack_trees_options *o,
350         struct cache_entry *idx,
351         struct cache_entry *tree)
352 {
353         struct rev_info *revs = o->unpack_data;
354         int match_missing, cached;
355
356         /* if the entry is not checked out, don't examine work tree */
357         cached = o->index_only ||
358                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
359         /*
360          * Backward compatibility wart - "diff-index -m" does
361          * not mean "do not ignore merges", but "match_missing".
362          *
363          * But with the revision flag parsing, that's found in
364          * "!revs->ignore_merges".
365          */
366         match_missing = !revs->ignore_merges;
367
368         if (cached && idx && ce_stage(idx)) {
369                 diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode,
370                              idx->sha1);
371                 return;
372         }
373
374         /*
375          * Something added to the tree?
376          */
377         if (!tree) {
378                 show_new_file(revs, idx, cached, match_missing);
379                 return;
380         }
381
382         /*
383          * Something removed from the tree?
384          */
385         if (!idx) {
386                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode, 0);
387                 return;
388         }
389
390         /* Show difference between old and new */
391         show_modified(revs, tree, idx, 1, cached, match_missing);
392 }
393
394 /*
395  * The unpack_trees() interface is designed for merging, so
396  * the different source entries are designed primarily for
397  * the source trees, with the old index being really mainly
398  * used for being replaced by the result.
399  *
400  * For diffing, the index is more important, and we only have a
401  * single tree.
402  *
403  * We're supposed to advance o->pos to skip what we have already processed.
404  *
405  * This wrapper makes it all more readable, and takes care of all
406  * the fairly complex unpack_trees() semantic requirements, including
407  * the skipping, the path matching, the type conflict cases etc.
408  */
409 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
410 {
411         struct cache_entry *idx = src[0];
412         struct cache_entry *tree = src[1];
413         struct rev_info *revs = o->unpack_data;
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         ent = revs->pending.objects[0].item;
439         tree_name = revs->pending.objects[0].name;
440         tree = parse_tree_indirect(ent->sha1);
441         if (!tree)
442                 return error("bad tree object %s", tree_name);
443
444         memset(&opts, 0, sizeof(opts));
445         opts.head_idx = 1;
446         opts.index_only = cached;
447         opts.diff_index_cached = (cached &&
448                                   !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
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_fix_diff_index(&revs->diffopt);
461         diffcore_std(&revs->diffopt);
462         diff_flush(&revs->diffopt);
463         return 0;
464 }
465
466 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
467 {
468         struct tree *tree;
469         struct rev_info revs;
470         int i;
471         struct cache_entry **dst;
472         struct cache_entry *last = NULL;
473         struct unpack_trees_options opts;
474         struct tree_desc t;
475
476         /*
477          * This is used by git-blame to run diff-cache internally;
478          * it potentially needs to repeatedly run this, so we will
479          * start by removing the higher order entries the last round
480          * left behind.
481          */
482         dst = active_cache;
483         for (i = 0; i < active_nr; i++) {
484                 struct cache_entry *ce = active_cache[i];
485                 if (ce_stage(ce)) {
486                         if (last && !strcmp(ce->name, last->name))
487                                 continue;
488                         cache_tree_invalidate_path(active_cache_tree,
489                                                    ce->name);
490                         last = ce;
491                         ce->ce_flags |= CE_REMOVE;
492                 }
493                 *dst++ = ce;
494         }
495         active_nr = dst - active_cache;
496
497         init_revisions(&revs, NULL);
498         revs.prune_data = opt->paths;
499         tree = parse_tree_indirect(tree_sha1);
500         if (!tree)
501                 die("bad tree object %s", sha1_to_hex(tree_sha1));
502
503         memset(&opts, 0, sizeof(opts));
504         opts.head_idx = 1;
505         opts.index_only = 1;
506         opts.diff_index_cached = !DIFF_OPT_TST(opt, FIND_COPIES_HARDER);
507         opts.merge = 1;
508         opts.fn = oneway_diff;
509         opts.unpack_data = &revs;
510         opts.src_index = &the_index;
511         opts.dst_index = &the_index;
512
513         init_tree_desc(&t, tree->buffer, tree->size);
514         if (unpack_trees(1, &t, &opts))
515                 exit(128);
516         return 0;
517 }
518
519 int index_differs_from(const char *def, int diff_flags)
520 {
521         struct rev_info rev;
522         struct setup_revision_opt opt;
523
524         init_revisions(&rev, NULL);
525         memset(&opt, 0, sizeof(opt));
526         opt.def = def;
527         setup_revisions(0, NULL, &rev, &opt);
528         DIFF_OPT_SET(&rev.diffopt, QUICK);
529         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
530         rev.diffopt.flags |= diff_flags;
531         run_diff_index(&rev, 1);
532         if (rev.pending.alloc)
533                 free(rev.pending.objects);
534         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
535 }