Merge branch 'nd/daemonize-gc'
[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                         memcpy(dpath->path, ce->name, path_len);
129                         dpath->path[path_len] = '\0';
130                         hashclr(dpath->sha1);
131                         memset(&(dpath->parent[0]), 0,
132                                sizeof(struct combine_diff_parent)*5);
133
134                         changed = check_removed(ce, &st);
135                         if (!changed)
136                                 wt_mode = ce_mode_from_stat(ce, st.st_mode);
137                         else {
138                                 if (changed < 0) {
139                                         perror(ce->name);
140                                         continue;
141                                 }
142                                 wt_mode = 0;
143                         }
144                         dpath->mode = wt_mode;
145
146                         while (i < entries) {
147                                 struct cache_entry *nce = active_cache[i];
148                                 int stage;
149
150                                 if (strcmp(ce->name, nce->name))
151                                         break;
152
153                                 /* Stage #2 (ours) is the first parent,
154                                  * stage #3 (theirs) is the second.
155                                  */
156                                 stage = ce_stage(nce);
157                                 if (2 <= stage) {
158                                         int mode = nce->ce_mode;
159                                         num_compare_stages++;
160                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
161                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
162                                         dpath->parent[stage-2].status =
163                                                 DIFF_STATUS_MODIFIED;
164                                 }
165
166                                 /* diff against the proper unmerged stage */
167                                 if (stage == diff_unmerged_stage)
168                                         ce = nce;
169                                 i++;
170                         }
171                         /*
172                          * Compensate for loop update
173                          */
174                         i--;
175
176                         if (revs->combine_merges && num_compare_stages == 2) {
177                                 show_combined_diff(dpath, 2,
178                                                    revs->dense_combined_merges,
179                                                    revs);
180                                 free(dpath);
181                                 continue;
182                         }
183                         free(dpath);
184                         dpath = NULL;
185
186                         /*
187                          * Show the diff for the 'ce' if we found the one
188                          * from the desired stage.
189                          */
190                         pair = diff_unmerge(&revs->diffopt, ce->name);
191                         if (wt_mode)
192                                 pair->two->mode = wt_mode;
193                         if (ce_stage(ce) != diff_unmerged_stage)
194                                 continue;
195                 }
196
197                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
198                         continue;
199
200                 /* If CE_VALID is set, don't look at workdir for file removal */
201                 changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
202                 if (changed) {
203                         if (changed < 0) {
204                                 perror(ce->name);
205                                 continue;
206                         }
207                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
208                                        ce->sha1, !is_null_sha1(ce->sha1),
209                                        ce->name, 0);
210                         continue;
211                 }
212                 changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
213                                                     ce_option, &dirty_submodule);
214                 if (!changed && !dirty_submodule) {
215                         ce_mark_uptodate(ce);
216                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
217                                 continue;
218                 }
219                 oldmode = ce->ce_mode;
220                 newmode = ce_mode_from_stat(ce, st.st_mode);
221                 diff_change(&revs->diffopt, oldmode, newmode,
222                             ce->sha1, (changed ? null_sha1 : ce->sha1),
223                             !is_null_sha1(ce->sha1), (changed ? 0 : !is_null_sha1(ce->sha1)),
224                             ce->name, 0, dirty_submodule);
225
226         }
227         diffcore_std(&revs->diffopt);
228         diff_flush(&revs->diffopt);
229         return 0;
230 }
231
232 /*
233  * diff-index
234  */
235
236 /* A file entry went away or appeared */
237 static void diff_index_show_file(struct rev_info *revs,
238                                  const char *prefix,
239                                  const struct cache_entry *ce,
240                                  const unsigned char *sha1, int sha1_valid,
241                                  unsigned int mode,
242                                  unsigned dirty_submodule)
243 {
244         diff_addremove(&revs->diffopt, prefix[0], mode,
245                        sha1, sha1_valid, ce->name, dirty_submodule);
246 }
247
248 static int get_stat_data(const struct cache_entry *ce,
249                          const unsigned char **sha1p,
250                          unsigned int *modep,
251                          int cached, int match_missing,
252                          unsigned *dirty_submodule, struct diff_options *diffopt)
253 {
254         const unsigned char *sha1 = ce->sha1;
255         unsigned int mode = ce->ce_mode;
256
257         if (!cached && !ce_uptodate(ce)) {
258                 int changed;
259                 struct stat st;
260                 changed = check_removed(ce, &st);
261                 if (changed < 0)
262                         return -1;
263                 else if (changed) {
264                         if (match_missing) {
265                                 *sha1p = sha1;
266                                 *modep = mode;
267                                 return 0;
268                         }
269                         return -1;
270                 }
271                 changed = match_stat_with_submodule(diffopt, ce, &st,
272                                                     0, dirty_submodule);
273                 if (changed) {
274                         mode = ce_mode_from_stat(ce, st.st_mode);
275                         sha1 = null_sha1;
276                 }
277         }
278
279         *sha1p = sha1;
280         *modep = mode;
281         return 0;
282 }
283
284 static void show_new_file(struct rev_info *revs,
285                           const struct cache_entry *new,
286                           int cached, int match_missing)
287 {
288         const unsigned char *sha1;
289         unsigned int mode;
290         unsigned dirty_submodule = 0;
291
292         /*
293          * New file in the index: it might actually be different in
294          * the working tree.
295          */
296         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
297             &dirty_submodule, &revs->diffopt) < 0)
298                 return;
299
300         diff_index_show_file(revs, "+", new, sha1, !is_null_sha1(sha1), mode, dirty_submodule);
301 }
302
303 static int show_modified(struct rev_info *revs,
304                          const struct cache_entry *old,
305                          const struct cache_entry *new,
306                          int report_missing,
307                          int cached, int match_missing)
308 {
309         unsigned int mode, oldmode;
310         const unsigned char *sha1;
311         unsigned dirty_submodule = 0;
312
313         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
314                           &dirty_submodule, &revs->diffopt) < 0) {
315                 if (report_missing)
316                         diff_index_show_file(revs, "-", old,
317                                              old->sha1, 1, old->ce_mode, 0);
318                 return -1;
319         }
320
321         if (revs->combine_merges && !cached &&
322             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
323                 struct combine_diff_path *p;
324                 int pathlen = ce_namelen(new);
325
326                 p = xmalloc(combine_diff_path_size(2, pathlen));
327                 p->path = (char *) &p->parent[2];
328                 p->next = NULL;
329                 memcpy(p->path, new->name, pathlen);
330                 p->path[pathlen] = 0;
331                 p->mode = mode;
332                 hashclr(p->sha1);
333                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
334                 p->parent[0].status = DIFF_STATUS_MODIFIED;
335                 p->parent[0].mode = new->ce_mode;
336                 hashcpy(p->parent[0].sha1, new->sha1);
337                 p->parent[1].status = DIFF_STATUS_MODIFIED;
338                 p->parent[1].mode = old->ce_mode;
339                 hashcpy(p->parent[1].sha1, old->sha1);
340                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
341                 free(p);
342                 return 0;
343         }
344
345         oldmode = old->ce_mode;
346         if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
347             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
348                 return 0;
349
350         diff_change(&revs->diffopt, oldmode, mode,
351                     old->sha1, sha1, 1, !is_null_sha1(sha1),
352                     old->name, 0, dirty_submodule);
353         return 0;
354 }
355
356 /*
357  * This gets a mix of an existing index and a tree, one pathname entry
358  * at a time. The index entry may be a single stage-0 one, but it could
359  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
360  * give you the position and number of entries in the index).
361  */
362 static void do_oneway_diff(struct unpack_trees_options *o,
363                            const struct cache_entry *idx,
364                            const struct cache_entry *tree)
365 {
366         struct rev_info *revs = o->unpack_data;
367         int match_missing, cached;
368
369         /* if the entry is not checked out, don't examine work tree */
370         cached = o->index_only ||
371                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
372         /*
373          * Backward compatibility wart - "diff-index -m" does
374          * not mean "do not ignore merges", but "match_missing".
375          *
376          * But with the revision flag parsing, that's found in
377          * "!revs->ignore_merges".
378          */
379         match_missing = !revs->ignore_merges;
380
381         if (cached && idx && ce_stage(idx)) {
382                 struct diff_filepair *pair;
383                 pair = diff_unmerge(&revs->diffopt, idx->name);
384                 if (tree)
385                         fill_filespec(pair->one, tree->sha1, 1, tree->ce_mode);
386                 return;
387         }
388
389         /*
390          * Something added to the tree?
391          */
392         if (!tree) {
393                 show_new_file(revs, idx, cached, match_missing);
394                 return;
395         }
396
397         /*
398          * Something removed from the tree?
399          */
400         if (!idx) {
401                 diff_index_show_file(revs, "-", tree, tree->sha1, 1, tree->ce_mode, 0);
402                 return;
403         }
404
405         /* Show difference between old and new */
406         show_modified(revs, tree, idx, 1, cached, match_missing);
407 }
408
409 /*
410  * The unpack_trees() interface is designed for merging, so
411  * the different source entries are designed primarily for
412  * the source trees, with the old index being really mainly
413  * used for being replaced by the result.
414  *
415  * For diffing, the index is more important, and we only have a
416  * single tree.
417  *
418  * We're supposed to advance o->pos to skip what we have already processed.
419  *
420  * This wrapper makes it all more readable, and takes care of all
421  * the fairly complex unpack_trees() semantic requirements, including
422  * the skipping, the path matching, the type conflict cases etc.
423  */
424 static int oneway_diff(const struct cache_entry * const *src,
425                        struct unpack_trees_options *o)
426 {
427         const struct cache_entry *idx = src[0];
428         const struct cache_entry *tree = src[1];
429         struct rev_info *revs = o->unpack_data;
430
431         /*
432          * Unpack-trees generates a DF/conflict entry if
433          * there was a directory in the index and a tree
434          * in the tree. From a diff standpoint, that's a
435          * delete of the tree and a create of the file.
436          */
437         if (tree == o->df_conflict_entry)
438                 tree = NULL;
439
440         if (ce_path_match(idx ? idx : tree, &revs->prune_data, NULL)) {
441                 do_oneway_diff(o, idx, tree);
442                 if (diff_can_quit_early(&revs->diffopt)) {
443                         o->exiting_early = 1;
444                         return -1;
445                 }
446         }
447
448         return 0;
449 }
450
451 static int diff_cache(struct rev_info *revs,
452                       const unsigned char *tree_sha1,
453                       const char *tree_name,
454                       int cached)
455 {
456         struct tree *tree;
457         struct tree_desc t;
458         struct unpack_trees_options opts;
459
460         tree = parse_tree_indirect(tree_sha1);
461         if (!tree)
462                 return error("bad tree object %s",
463                              tree_name ? tree_name : sha1_to_hex(tree_sha1));
464         memset(&opts, 0, sizeof(opts));
465         opts.head_idx = 1;
466         opts.index_only = cached;
467         opts.diff_index_cached = (cached &&
468                                   !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
469         opts.merge = 1;
470         opts.fn = oneway_diff;
471         opts.unpack_data = revs;
472         opts.src_index = &the_index;
473         opts.dst_index = NULL;
474         opts.pathspec = &revs->diffopt.pathspec;
475         opts.pathspec->recursive = 1;
476
477         init_tree_desc(&t, tree->buffer, tree->size);
478         return unpack_trees(1, &t, &opts);
479 }
480
481 int run_diff_index(struct rev_info *revs, int cached)
482 {
483         struct object_array_entry *ent;
484
485         ent = revs->pending.objects;
486         if (diff_cache(revs, ent->item->sha1, ent->name, cached))
487                 exit(128);
488
489         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
490         diffcore_fix_diff_index(&revs->diffopt);
491         diffcore_std(&revs->diffopt);
492         diff_flush(&revs->diffopt);
493         return 0;
494 }
495
496 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
497 {
498         struct rev_info revs;
499
500         init_revisions(&revs, NULL);
501         copy_pathspec(&revs.prune_data, &opt->pathspec);
502         revs.diffopt = *opt;
503
504         if (diff_cache(&revs, tree_sha1, NULL, 1))
505                 exit(128);
506         return 0;
507 }
508
509 int index_differs_from(const char *def, int diff_flags)
510 {
511         struct rev_info rev;
512         struct setup_revision_opt opt;
513
514         init_revisions(&rev, NULL);
515         memset(&opt, 0, sizeof(opt));
516         opt.def = def;
517         setup_revisions(0, NULL, &rev, &opt);
518         DIFF_OPT_SET(&rev.diffopt, QUICK);
519         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
520         rev.diffopt.flags |= diff_flags;
521         run_diff_index(&rev, 1);
522         if (rev.pending.alloc)
523                 free(rev.pending.objects);
524         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
525 }