compat/poll: sleep 1 millisecond to avoid busy wait
[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
16 /*
17  * diff-files
18  */
19
20 /*
21  * Has the work tree entity been removed?
22  *
23  * Return 1 if it was removed from the work tree, 0 if an entity to be
24  * compared with the cache entry ce still exists (the latter includes
25  * the case where a directory that is not a submodule repository
26  * exists for ce that is a submodule -- it is a submodule that is not
27  * checked out).  Return negative for an error.
28  */
29 static int check_removed(const struct cache_entry *ce, struct stat *st)
30 {
31         if (lstat(ce->name, st) < 0) {
32                 if (errno != ENOENT && errno != ENOTDIR)
33                         return -1;
34                 return 1;
35         }
36         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
37                 return 1;
38         if (S_ISDIR(st->st_mode)) {
39                 unsigned char sub[20];
40
41                 /*
42                  * If ce is already a gitlink, we can have a plain
43                  * directory (i.e. the submodule is not checked out),
44                  * or a checked out submodule.  Either case this is not
45                  * a case where something was removed from the work tree,
46                  * so we will return 0.
47                  *
48                  * Otherwise, if the directory is not a submodule
49                  * repository, that means ce which was a blob turned into
50                  * a directory --- the blob was removed!
51                  */
52                 if (!S_ISGITLINK(ce->ce_mode) &&
53                     resolve_gitlink_ref(ce->name, "HEAD", sub))
54                         return 1;
55         }
56         return 0;
57 }
58
59 /*
60  * Has a file changed or has a submodule new commits or a dirty work tree?
61  *
62  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
63  * option is set, the caller does not only want to know if a submodule is
64  * modified at all but wants to know all the conditions that are met (new
65  * commits, untracked content and/or modified content).
66  */
67 static int match_stat_with_submodule(struct diff_options *diffopt,
68                                      const struct cache_entry *ce,
69                                      struct stat *st, unsigned ce_option,
70                                      unsigned *dirty_submodule)
71 {
72         int changed = ce_match_stat(ce, st, ce_option);
73         if (S_ISGITLINK(ce->ce_mode)) {
74                 unsigned orig_flags = diffopt->flags;
75                 if (!DIFF_OPT_TST(diffopt, OVERRIDE_SUBMODULE_CONFIG))
76                         set_diffopt_flags_from_submodule_config(diffopt, ce->name);
77                 if (DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES))
78                         changed = 0;
79                 else if (!DIFF_OPT_TST(diffopt, IGNORE_DIRTY_SUBMODULES)
80                     && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES)))
81                         *dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
82                 diffopt->flags = orig_flags;
83         }
84         return changed;
85 }
86
87 int run_diff_files(struct rev_info *revs, unsigned int option)
88 {
89         int entries, i;
90         int diff_unmerged_stage = revs->max_count;
91         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
92                               ? CE_MATCH_RACY_IS_DIRTY : 0);
93
94         if (option & DIFF_SILENT_ON_REMOVED)
95                 handle_deprecated_show_diff_q(&revs->diffopt);
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                 struct stat st;
104                 unsigned int oldmode, newmode;
105                 struct cache_entry *ce = active_cache[i];
106                 int changed;
107                 unsigned dirty_submodule = 0;
108
109                 if (diff_can_quit_early(&revs->diffopt))
110                         break;
111
112                 if (!ce_path_match(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
122                         path_len = ce_namelen(ce);
123
124                         dpath = xmalloc(combine_diff_path_size(5, path_len));
125                         dpath->path = (char *) &(dpath->parent[5]);
126
127                         dpath->next = NULL;
128                         dpath->len = path_len;
129                         memcpy(dpath->path, ce->name, path_len);
130                         dpath->path[path_len] = '\0';
131                         hashclr(dpath->sha1);
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                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
162                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
163                                         dpath->parent[stage-2].status =
164                                                 DIFF_STATUS_MODIFIED;
165                                 }
166
167                                 /* diff against the proper unmerged stage */
168                                 if (stage == diff_unmerged_stage)
169                                         ce = nce;
170                                 i++;
171                         }
172                         /*
173                          * Compensate for loop update
174                          */
175                         i--;
176
177                         if (revs->combine_merges && num_compare_stages == 2) {
178                                 show_combined_diff(dpath, 2,
179                                                    revs->dense_combined_merges,
180                                                    revs);
181                                 free(dpath);
182                                 continue;
183                         }
184                         free(dpath);
185                         dpath = NULL;
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                 changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
203                 if (changed) {
204                         if (changed < 0) {
205                                 perror(ce->name);
206                                 continue;
207                         }
208                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
209                                        ce->sha1, !is_null_sha1(ce->sha1),
210                                        ce->name, 0);
211                         continue;
212                 }
213                 changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
214                                                     ce_option, &dirty_submodule);
215                 if (!changed && !dirty_submodule) {
216                         ce_mark_uptodate(ce);
217                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
218                                 continue;
219                 }
220                 oldmode = ce->ce_mode;
221                 newmode = ce_mode_from_stat(ce, st.st_mode);
222                 diff_change(&revs->diffopt, oldmode, newmode,
223                             ce->sha1, (changed ? null_sha1 : ce->sha1),
224                             !is_null_sha1(ce->sha1), (changed ? 0 : !is_null_sha1(ce->sha1)),
225                             ce->name, 0, dirty_submodule);
226
227         }
228         diffcore_std(&revs->diffopt);
229         diff_flush(&revs->diffopt);
230         return 0;
231 }
232
233 /*
234  * diff-index
235  */
236
237 /* A file entry went away or appeared */
238 static void diff_index_show_file(struct rev_info *revs,
239                                  const char *prefix,
240                                  const struct cache_entry *ce,
241                                  const unsigned char *sha1, int sha1_valid,
242                                  unsigned int mode,
243                                  unsigned dirty_submodule)
244 {
245         diff_addremove(&revs->diffopt, prefix[0], mode,
246                        sha1, sha1_valid, ce->name, dirty_submodule);
247 }
248
249 static int get_stat_data(const struct cache_entry *ce,
250                          const unsigned char **sha1p,
251                          unsigned int *modep,
252                          int cached, int match_missing,
253                          unsigned *dirty_submodule, struct diff_options *diffopt)
254 {
255         const unsigned char *sha1 = ce->sha1;
256         unsigned int mode = ce->ce_mode;
257
258         if (!cached && !ce_uptodate(ce)) {
259                 int changed;
260                 struct stat st;
261                 changed = check_removed(ce, &st);
262                 if (changed < 0)
263                         return -1;
264                 else if (changed) {
265                         if (match_missing) {
266                                 *sha1p = sha1;
267                                 *modep = mode;
268                                 return 0;
269                         }
270                         return -1;
271                 }
272                 changed = match_stat_with_submodule(diffopt, ce, &st,
273                                                     0, dirty_submodule);
274                 if (changed) {
275                         mode = ce_mode_from_stat(ce, st.st_mode);
276                         sha1 = null_sha1;
277                 }
278         }
279
280         *sha1p = sha1;
281         *modep = mode;
282         return 0;
283 }
284
285 static void show_new_file(struct rev_info *revs,
286                           const struct cache_entry *new,
287                           int cached, int match_missing)
288 {
289         const unsigned char *sha1;
290         unsigned int mode;
291         unsigned dirty_submodule = 0;
292
293         /*
294          * New file in the index: it might actually be different in
295          * the working tree.
296          */
297         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
298             &dirty_submodule, &revs->diffopt) < 0)
299                 return;
300
301         diff_index_show_file(revs, "+", new, sha1, !is_null_sha1(sha1), mode, dirty_submodule);
302 }
303
304 static int show_modified(struct rev_info *revs,
305                          const struct cache_entry *old,
306                          const struct cache_entry *new,
307                          int report_missing,
308                          int cached, int match_missing)
309 {
310         unsigned int mode, oldmode;
311         const unsigned char *sha1;
312         unsigned dirty_submodule = 0;
313
314         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
315                           &dirty_submodule, &revs->diffopt) < 0) {
316                 if (report_missing)
317                         diff_index_show_file(revs, "-", old,
318                                              old->sha1, 1, old->ce_mode, 0);
319                 return -1;
320         }
321
322         if (revs->combine_merges && !cached &&
323             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
324                 struct combine_diff_path *p;
325                 int pathlen = ce_namelen(new);
326
327                 p = xmalloc(combine_diff_path_size(2, pathlen));
328                 p->path = (char *) &p->parent[2];
329                 p->next = NULL;
330                 p->len = pathlen;
331                 memcpy(p->path, new->name, pathlen);
332                 p->path[pathlen] = 0;
333                 p->mode = mode;
334                 hashclr(p->sha1);
335                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
336                 p->parent[0].status = DIFF_STATUS_MODIFIED;
337                 p->parent[0].mode = new->ce_mode;
338                 hashcpy(p->parent[0].sha1, new->sha1);
339                 p->parent[1].status = DIFF_STATUS_MODIFIED;
340                 p->parent[1].mode = old->ce_mode;
341                 hashcpy(p->parent[1].sha1, old->sha1);
342                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
343                 free(p);
344                 return 0;
345         }
346
347         oldmode = old->ce_mode;
348         if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
349             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
350                 return 0;
351
352         diff_change(&revs->diffopt, oldmode, mode,
353                     old->sha1, sha1, 1, !is_null_sha1(sha1),
354                     old->name, 0, dirty_submodule);
355         return 0;
356 }
357
358 /*
359  * This gets a mix of an existing index and a tree, one pathname entry
360  * at a time. The index entry may be a single stage-0 one, but it could
361  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
362  * give you the position and number of entries in the index).
363  */
364 static void do_oneway_diff(struct unpack_trees_options *o,
365                            const struct cache_entry *idx,
366                            const struct cache_entry *tree)
367 {
368         struct rev_info *revs = o->unpack_data;
369         int match_missing, cached;
370
371         /* if the entry is not checked out, don't examine work tree */
372         cached = o->index_only ||
373                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
374         /*
375          * Backward compatibility wart - "diff-index -m" does
376          * not mean "do not ignore merges", but "match_missing".
377          *
378          * But with the revision flag parsing, that's found in
379          * "!revs->ignore_merges".
380          */
381         match_missing = !revs->ignore_merges;
382
383         if (cached && idx && ce_stage(idx)) {
384                 struct diff_filepair *pair;
385                 pair = diff_unmerge(&revs->diffopt, idx->name);
386                 if (tree)
387                         fill_filespec(pair->one, tree->sha1, 1, tree->ce_mode);
388                 return;
389         }
390
391         /*
392          * Something added to the tree?
393          */
394         if (!tree) {
395                 show_new_file(revs, idx, cached, match_missing);
396                 return;
397         }
398
399         /*
400          * Something removed from the tree?
401          */
402         if (!idx) {
403                 diff_index_show_file(revs, "-", tree, tree->sha1, 1, tree->ce_mode, 0);
404                 return;
405         }
406
407         /* Show difference between old and new */
408         show_modified(revs, tree, idx, 1, cached, match_missing);
409 }
410
411 /*
412  * The unpack_trees() interface is designed for merging, so
413  * the different source entries are designed primarily for
414  * the source trees, with the old index being really mainly
415  * used for being replaced by the result.
416  *
417  * For diffing, the index is more important, and we only have a
418  * single tree.
419  *
420  * We're supposed to advance o->pos to skip what we have already processed.
421  *
422  * This wrapper makes it all more readable, and takes care of all
423  * the fairly complex unpack_trees() semantic requirements, including
424  * the skipping, the path matching, the type conflict cases etc.
425  */
426 static int oneway_diff(const struct cache_entry * const *src,
427                        struct unpack_trees_options *o)
428 {
429         const struct cache_entry *idx = src[0];
430         const struct cache_entry *tree = src[1];
431         struct rev_info *revs = o->unpack_data;
432
433         /*
434          * Unpack-trees generates a DF/conflict entry if
435          * there was a directory in the index and a tree
436          * in the tree. From a diff standpoint, that's a
437          * delete of the tree and a create of the file.
438          */
439         if (tree == o->df_conflict_entry)
440                 tree = NULL;
441
442         if (ce_path_match(idx ? idx : tree, &revs->prune_data, NULL)) {
443                 do_oneway_diff(o, idx, tree);
444                 if (diff_can_quit_early(&revs->diffopt)) {
445                         o->exiting_early = 1;
446                         return -1;
447                 }
448         }
449
450         return 0;
451 }
452
453 static int diff_cache(struct rev_info *revs,
454                       const unsigned char *tree_sha1,
455                       const char *tree_name,
456                       int cached)
457 {
458         struct tree *tree;
459         struct tree_desc t;
460         struct unpack_trees_options opts;
461
462         tree = parse_tree_indirect(tree_sha1);
463         if (!tree)
464                 return error("bad tree object %s",
465                              tree_name ? tree_name : sha1_to_hex(tree_sha1));
466         memset(&opts, 0, sizeof(opts));
467         opts.head_idx = 1;
468         opts.index_only = cached;
469         opts.diff_index_cached = (cached &&
470                                   !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
471         opts.merge = 1;
472         opts.fn = oneway_diff;
473         opts.unpack_data = revs;
474         opts.src_index = &the_index;
475         opts.dst_index = NULL;
476         opts.pathspec = &revs->diffopt.pathspec;
477         opts.pathspec->recursive = 1;
478
479         init_tree_desc(&t, tree->buffer, tree->size);
480         return unpack_trees(1, &t, &opts);
481 }
482
483 int run_diff_index(struct rev_info *revs, int cached)
484 {
485         struct object_array_entry *ent;
486
487         ent = revs->pending.objects;
488         if (diff_cache(revs, ent->item->sha1, ent->name, cached))
489                 exit(128);
490
491         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
492         diffcore_fix_diff_index(&revs->diffopt);
493         diffcore_std(&revs->diffopt);
494         diff_flush(&revs->diffopt);
495         return 0;
496 }
497
498 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
499 {
500         struct rev_info revs;
501
502         init_revisions(&revs, NULL);
503         copy_pathspec(&revs.prune_data, &opt->pathspec);
504         revs.diffopt = *opt;
505
506         if (diff_cache(&revs, tree_sha1, NULL, 1))
507                 exit(128);
508         return 0;
509 }
510
511 int index_differs_from(const char *def, int diff_flags)
512 {
513         struct rev_info rev;
514         struct setup_revision_opt opt;
515
516         init_revisions(&rev, NULL);
517         memset(&opt, 0, sizeof(opt));
518         opt.def = def;
519         setup_revisions(0, NULL, &rev, &opt);
520         DIFF_OPT_SET(&rev.diffopt, QUICK);
521         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
522         rev.diffopt.flags |= diff_flags;
523         run_diff_index(&rev, 1);
524         if (rev.pending.alloc)
525                 free(rev.pending.objects);
526         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
527 }