t1700-split-index: date back files to avoid racy situations
[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 #include "dir.h"
15 #include "fsmonitor.h"
16
17 /*
18  * diff-files
19  */
20
21 /*
22  * Has the work tree entity been removed?
23  *
24  * Return 1 if it was removed from the work tree, 0 if an entity to be
25  * compared with the cache entry ce still exists (the latter includes
26  * the case where a directory that is not a submodule repository
27  * exists for ce that is a submodule -- it is a submodule that is not
28  * checked out).  Return negative for an error.
29  */
30 static int check_removed(const struct cache_entry *ce, struct stat *st)
31 {
32         if (lstat(ce->name, st) < 0) {
33                 if (!is_missing_file_error(errno))
34                         return -1;
35                 return 1;
36         }
37         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
38                 return 1;
39         if (S_ISDIR(st->st_mode)) {
40                 struct object_id sub;
41
42                 /*
43                  * If ce is already a gitlink, we can have a plain
44                  * directory (i.e. the submodule is not checked out),
45                  * or a checked out submodule.  Either case this is not
46                  * a case where something was removed from the work tree,
47                  * so we will return 0.
48                  *
49                  * Otherwise, if the directory is not a submodule
50                  * repository, that means ce which was a blob turned into
51                  * a directory --- the blob was removed!
52                  */
53                 if (!S_ISGITLINK(ce->ce_mode) &&
54                     resolve_gitlink_ref(ce->name, "HEAD", &sub))
55                         return 1;
56         }
57         return 0;
58 }
59
60 /*
61  * Has a file changed or has a submodule new commits or a dirty work tree?
62  *
63  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
64  * option is set, the caller does not only want to know if a submodule is
65  * modified at all but wants to know all the conditions that are met (new
66  * commits, untracked content and/or modified content).
67  */
68 static int match_stat_with_submodule(struct diff_options *diffopt,
69                                      const struct cache_entry *ce,
70                                      struct stat *st, unsigned ce_option,
71                                      unsigned *dirty_submodule)
72 {
73         int changed = ce_match_stat(ce, st, ce_option);
74         if (S_ISGITLINK(ce->ce_mode)) {
75                 struct diff_flags orig_flags = diffopt->flags;
76                 if (!diffopt->flags.override_submodule_config)
77                         set_diffopt_flags_from_submodule_config(diffopt, ce->name);
78                 if (diffopt->flags.ignore_submodules)
79                         changed = 0;
80                 else if (!diffopt->flags.ignore_dirty_submodules &&
81                          (!changed || diffopt->flags.dirty_submodules))
82                         *dirty_submodule = is_submodule_modified(ce->name,
83                                                                  diffopt->flags.ignore_untracked_in_submodules);
84                 diffopt->flags = orig_flags;
85         }
86         return changed;
87 }
88
89 int run_diff_files(struct rev_info *revs, unsigned int option)
90 {
91         int entries, i;
92         int diff_unmerged_stage = revs->max_count;
93         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
94                               ? CE_MATCH_RACY_IS_DIRTY : 0);
95         uint64_t start = getnanotime();
96
97         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
98
99         if (diff_unmerged_stage < 0)
100                 diff_unmerged_stage = 2;
101         entries = active_nr;
102         for (i = 0; i < entries; i++) {
103                 unsigned int oldmode, newmode;
104                 struct cache_entry *ce = active_cache[i];
105                 int changed;
106                 unsigned dirty_submodule = 0;
107                 const struct object_id *old_oid, *new_oid;
108
109                 if (diff_can_quit_early(&revs->diffopt))
110                         break;
111
112                 if (!ce_path_match(&the_index, ce, &revs->prune_data, NULL))
113                         continue;
114
115                 if (ce_stage(ce)) {
116                         struct combine_diff_path *dpath;
117                         struct diff_filepair *pair;
118                         unsigned int wt_mode = 0;
119                         int num_compare_stages = 0;
120                         size_t path_len;
121                         struct stat st;
122
123                         path_len = ce_namelen(ce);
124
125                         dpath = xmalloc(combine_diff_path_size(5, path_len));
126                         dpath->path = (char *) &(dpath->parent[5]);
127
128                         dpath->next = NULL;
129                         memcpy(dpath->path, ce->name, path_len);
130                         dpath->path[path_len] = '\0';
131                         oidclr(&dpath->oid);
132                         memset(&(dpath->parent[0]), 0,
133                                sizeof(struct combine_diff_parent)*5);
134
135                         changed = check_removed(ce, &st);
136                         if (!changed)
137                                 wt_mode = ce_mode_from_stat(ce, st.st_mode);
138                         else {
139                                 if (changed < 0) {
140                                         perror(ce->name);
141                                         continue;
142                                 }
143                                 wt_mode = 0;
144                         }
145                         dpath->mode = wt_mode;
146
147                         while (i < entries) {
148                                 struct cache_entry *nce = active_cache[i];
149                                 int stage;
150
151                                 if (strcmp(ce->name, nce->name))
152                                         break;
153
154                                 /* Stage #2 (ours) is the first parent,
155                                  * stage #3 (theirs) is the second.
156                                  */
157                                 stage = ce_stage(nce);
158                                 if (2 <= stage) {
159                                         int mode = nce->ce_mode;
160                                         num_compare_stages++;
161                                         oidcpy(&dpath->parent[stage - 2].oid,
162                                                &nce->oid);
163                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
164                                         dpath->parent[stage-2].status =
165                                                 DIFF_STATUS_MODIFIED;
166                                 }
167
168                                 /* diff against the proper unmerged stage */
169                                 if (stage == diff_unmerged_stage)
170                                         ce = nce;
171                                 i++;
172                         }
173                         /*
174                          * Compensate for loop update
175                          */
176                         i--;
177
178                         if (revs->combine_merges && num_compare_stages == 2) {
179                                 show_combined_diff(dpath, 2,
180                                                    revs->dense_combined_merges,
181                                                    revs);
182                                 free(dpath);
183                                 continue;
184                         }
185                         FREE_AND_NULL(dpath);
186
187                         /*
188                          * Show the diff for the 'ce' if we found the one
189                          * from the desired stage.
190                          */
191                         pair = diff_unmerge(&revs->diffopt, ce->name);
192                         if (wt_mode)
193                                 pair->two->mode = wt_mode;
194                         if (ce_stage(ce) != diff_unmerged_stage)
195                                 continue;
196                 }
197
198                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
199                         continue;
200
201                 /* If CE_VALID is set, don't look at workdir for file removal */
202                 if (ce->ce_flags & CE_VALID) {
203                         changed = 0;
204                         newmode = ce->ce_mode;
205                 } else {
206                         struct stat st;
207
208                         changed = check_removed(ce, &st);
209                         if (changed) {
210                                 if (changed < 0) {
211                                         perror(ce->name);
212                                         continue;
213                                 }
214                                 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
215                                                &ce->oid,
216                                                !is_null_oid(&ce->oid),
217                                                ce->name, 0);
218                                 continue;
219                         } else if (revs->diffopt.ita_invisible_in_index &&
220                                    ce_intent_to_add(ce)) {
221                                 diff_addremove(&revs->diffopt, '+', ce->ce_mode,
222                                                the_hash_algo->empty_tree, 0,
223                                                ce->name, 0);
224                                 continue;
225                         }
226
227                         changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
228                                                             ce_option, &dirty_submodule);
229                         newmode = ce_mode_from_stat(ce, st.st_mode);
230                 }
231
232                 if (!changed && !dirty_submodule) {
233                         ce_mark_uptodate(ce);
234                         mark_fsmonitor_valid(ce);
235                         if (!revs->diffopt.flags.find_copies_harder)
236                                 continue;
237                 }
238                 oldmode = ce->ce_mode;
239                 old_oid = &ce->oid;
240                 new_oid = changed ? &null_oid : &ce->oid;
241                 diff_change(&revs->diffopt, oldmode, newmode,
242                             old_oid, new_oid,
243                             !is_null_oid(old_oid),
244                             !is_null_oid(new_oid),
245                             ce->name, 0, dirty_submodule);
246
247         }
248         diffcore_std(&revs->diffopt);
249         diff_flush(&revs->diffopt);
250         trace_performance_since(start, "diff-files");
251         return 0;
252 }
253
254 /*
255  * diff-index
256  */
257
258 /* A file entry went away or appeared */
259 static void diff_index_show_file(struct rev_info *revs,
260                                  const char *prefix,
261                                  const struct cache_entry *ce,
262                                  const struct object_id *oid, int oid_valid,
263                                  unsigned int mode,
264                                  unsigned dirty_submodule)
265 {
266         diff_addremove(&revs->diffopt, prefix[0], mode,
267                        oid, oid_valid, ce->name, dirty_submodule);
268 }
269
270 static int get_stat_data(const struct cache_entry *ce,
271                          const struct object_id **oidp,
272                          unsigned int *modep,
273                          int cached, int match_missing,
274                          unsigned *dirty_submodule, struct diff_options *diffopt)
275 {
276         const struct object_id *oid = &ce->oid;
277         unsigned int mode = ce->ce_mode;
278
279         if (!cached && !ce_uptodate(ce)) {
280                 int changed;
281                 struct stat st;
282                 changed = check_removed(ce, &st);
283                 if (changed < 0)
284                         return -1;
285                 else if (changed) {
286                         if (match_missing) {
287                                 *oidp = oid;
288                                 *modep = mode;
289                                 return 0;
290                         }
291                         return -1;
292                 }
293                 changed = match_stat_with_submodule(diffopt, ce, &st,
294                                                     0, dirty_submodule);
295                 if (changed) {
296                         mode = ce_mode_from_stat(ce, st.st_mode);
297                         oid = &null_oid;
298                 }
299         }
300
301         *oidp = oid;
302         *modep = mode;
303         return 0;
304 }
305
306 static void show_new_file(struct rev_info *revs,
307                           const struct cache_entry *new_file,
308                           int cached, int match_missing)
309 {
310         const struct object_id *oid;
311         unsigned int mode;
312         unsigned dirty_submodule = 0;
313
314         /*
315          * New file in the index: it might actually be different in
316          * the working tree.
317          */
318         if (get_stat_data(new_file, &oid, &mode, cached, match_missing,
319             &dirty_submodule, &revs->diffopt) < 0)
320                 return;
321
322         diff_index_show_file(revs, "+", new_file, oid, !is_null_oid(oid), mode, dirty_submodule);
323 }
324
325 static int show_modified(struct rev_info *revs,
326                          const struct cache_entry *old_entry,
327                          const struct cache_entry *new_entry,
328                          int report_missing,
329                          int cached, int match_missing)
330 {
331         unsigned int mode, oldmode;
332         const struct object_id *oid;
333         unsigned dirty_submodule = 0;
334
335         if (get_stat_data(new_entry, &oid, &mode, cached, match_missing,
336                           &dirty_submodule, &revs->diffopt) < 0) {
337                 if (report_missing)
338                         diff_index_show_file(revs, "-", old_entry,
339                                              &old_entry->oid, 1, old_entry->ce_mode,
340                                              0);
341                 return -1;
342         }
343
344         if (revs->combine_merges && !cached &&
345             (oidcmp(oid, &old_entry->oid) || oidcmp(&old_entry->oid, &new_entry->oid))) {
346                 struct combine_diff_path *p;
347                 int pathlen = ce_namelen(new_entry);
348
349                 p = xmalloc(combine_diff_path_size(2, pathlen));
350                 p->path = (char *) &p->parent[2];
351                 p->next = NULL;
352                 memcpy(p->path, new_entry->name, pathlen);
353                 p->path[pathlen] = 0;
354                 p->mode = mode;
355                 oidclr(&p->oid);
356                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
357                 p->parent[0].status = DIFF_STATUS_MODIFIED;
358                 p->parent[0].mode = new_entry->ce_mode;
359                 oidcpy(&p->parent[0].oid, &new_entry->oid);
360                 p->parent[1].status = DIFF_STATUS_MODIFIED;
361                 p->parent[1].mode = old_entry->ce_mode;
362                 oidcpy(&p->parent[1].oid, &old_entry->oid);
363                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
364                 free(p);
365                 return 0;
366         }
367
368         oldmode = old_entry->ce_mode;
369         if (mode == oldmode && !oidcmp(oid, &old_entry->oid) && !dirty_submodule &&
370             !revs->diffopt.flags.find_copies_harder)
371                 return 0;
372
373         diff_change(&revs->diffopt, oldmode, mode,
374                     &old_entry->oid, oid, 1, !is_null_oid(oid),
375                     old_entry->name, 0, dirty_submodule);
376         return 0;
377 }
378
379 /*
380  * This gets a mix of an existing index and a tree, one pathname entry
381  * at a time. The index entry may be a single stage-0 one, but it could
382  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
383  * give you the position and number of entries in the index).
384  */
385 static void do_oneway_diff(struct unpack_trees_options *o,
386                            const struct cache_entry *idx,
387                            const struct cache_entry *tree)
388 {
389         struct rev_info *revs = o->unpack_data;
390         int match_missing, cached;
391
392         /*
393          * i-t-a entries do not actually exist in the index (if we're
394          * looking at its content)
395          */
396         if (o->index_only &&
397             revs->diffopt.ita_invisible_in_index &&
398             idx && ce_intent_to_add(idx)) {
399                 idx = NULL;
400                 if (!tree)
401                         return; /* nothing to diff.. */
402         }
403
404         /* if the entry is not checked out, don't examine work tree */
405         cached = o->index_only ||
406                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
407         /*
408          * Backward compatibility wart - "diff-index -m" does
409          * not mean "do not ignore merges", but "match_missing".
410          *
411          * But with the revision flag parsing, that's found in
412          * "!revs->ignore_merges".
413          */
414         match_missing = !revs->ignore_merges;
415
416         if (cached && idx && ce_stage(idx)) {
417                 struct diff_filepair *pair;
418                 pair = diff_unmerge(&revs->diffopt, idx->name);
419                 if (tree)
420                         fill_filespec(pair->one, &tree->oid, 1,
421                                       tree->ce_mode);
422                 return;
423         }
424
425         /*
426          * Something added to the tree?
427          */
428         if (!tree) {
429                 show_new_file(revs, idx, cached, match_missing);
430                 return;
431         }
432
433         /*
434          * Something removed from the tree?
435          */
436         if (!idx) {
437                 diff_index_show_file(revs, "-", tree, &tree->oid, 1,
438                                      tree->ce_mode, 0);
439                 return;
440         }
441
442         /* Show difference between old and new */
443         show_modified(revs, tree, idx, 1, cached, match_missing);
444 }
445
446 /*
447  * The unpack_trees() interface is designed for merging, so
448  * the different source entries are designed primarily for
449  * the source trees, with the old index being really mainly
450  * used for being replaced by the result.
451  *
452  * For diffing, the index is more important, and we only have a
453  * single tree.
454  *
455  * We're supposed to advance o->pos to skip what we have already processed.
456  *
457  * This wrapper makes it all more readable, and takes care of all
458  * the fairly complex unpack_trees() semantic requirements, including
459  * the skipping, the path matching, the type conflict cases etc.
460  */
461 static int oneway_diff(const struct cache_entry * const *src,
462                        struct unpack_trees_options *o)
463 {
464         const struct cache_entry *idx = src[0];
465         const struct cache_entry *tree = src[1];
466         struct rev_info *revs = o->unpack_data;
467
468         /*
469          * Unpack-trees generates a DF/conflict entry if
470          * there was a directory in the index and a tree
471          * in the tree. From a diff standpoint, that's a
472          * delete of the tree and a create of the file.
473          */
474         if (tree == o->df_conflict_entry)
475                 tree = NULL;
476
477         if (ce_path_match(&the_index, idx ? idx : tree, &revs->prune_data, NULL)) {
478                 do_oneway_diff(o, idx, tree);
479                 if (diff_can_quit_early(&revs->diffopt)) {
480                         o->exiting_early = 1;
481                         return -1;
482                 }
483         }
484
485         return 0;
486 }
487
488 static int diff_cache(struct rev_info *revs,
489                       const struct object_id *tree_oid,
490                       const char *tree_name,
491                       int cached)
492 {
493         struct tree *tree;
494         struct tree_desc t;
495         struct unpack_trees_options opts;
496
497         tree = parse_tree_indirect(tree_oid);
498         if (!tree)
499                 return error("bad tree object %s",
500                              tree_name ? tree_name : oid_to_hex(tree_oid));
501         memset(&opts, 0, sizeof(opts));
502         opts.head_idx = 1;
503         opts.index_only = cached;
504         opts.diff_index_cached = (cached &&
505                                   !revs->diffopt.flags.find_copies_harder);
506         opts.merge = 1;
507         opts.fn = oneway_diff;
508         opts.unpack_data = revs;
509         opts.src_index = &the_index;
510         opts.dst_index = NULL;
511         opts.pathspec = &revs->diffopt.pathspec;
512         opts.pathspec->recursive = 1;
513
514         init_tree_desc(&t, tree->buffer, tree->size);
515         return unpack_trees(1, &t, &opts);
516 }
517
518 int run_diff_index(struct rev_info *revs, int cached)
519 {
520         struct object_array_entry *ent;
521         uint64_t start = getnanotime();
522
523         if (revs->pending.nr != 1)
524                 BUG("run_diff_index must be passed exactly one tree");
525
526         ent = revs->pending.objects;
527         if (diff_cache(revs, &ent->item->oid, ent->name, cached))
528                 exit(128);
529
530         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
531         diffcore_fix_diff_index(&revs->diffopt);
532         diffcore_std(&revs->diffopt);
533         diff_flush(&revs->diffopt);
534         trace_performance_since(start, "diff-index");
535         return 0;
536 }
537
538 int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
539 {
540         struct rev_info revs;
541
542         init_revisions(&revs, NULL);
543         copy_pathspec(&revs.prune_data, &opt->pathspec);
544         revs.diffopt = *opt;
545
546         if (diff_cache(&revs, tree_oid, NULL, 1))
547                 exit(128);
548         return 0;
549 }
550
551 int index_differs_from(const char *def, const struct diff_flags *flags,
552                        int ita_invisible_in_index)
553 {
554         struct rev_info rev;
555         struct setup_revision_opt opt;
556
557         init_revisions(&rev, NULL);
558         memset(&opt, 0, sizeof(opt));
559         opt.def = def;
560         setup_revisions(0, NULL, &rev, &opt);
561         rev.diffopt.flags.quick = 1;
562         rev.diffopt.flags.exit_with_status = 1;
563         if (flags)
564                 diff_flags_or(&rev.diffopt.flags, flags);
565         rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
566         run_diff_index(&rev, 1);
567         object_array_clear(&rev.pending);
568         return (rev.diffopt.flags.has_changes != 0);
569 }