fsmonitor: teach git to optionally utilize a file system monitor to speed up detectin...
[git/git.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 unsigned char sub[20];
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 unsigned orig_flags = diffopt->flags;
76 if (!DIFF_OPT_TST(diffopt, OVERRIDE_SUBMODULE_CONFIG))
77 set_diffopt_flags_from_submodule_config(diffopt, ce->name);
78 if (DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES))
79 changed = 0;
80 else if (!DIFF_OPT_TST(diffopt, IGNORE_DIRTY_SUBMODULES)
81 && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES)))
82 *dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
83 diffopt->flags = orig_flags;
84 }
85 return changed;
86 }
87
88 int run_diff_files(struct rev_info *revs, unsigned int option)
89 {
90 int entries, i;
91 int diff_unmerged_stage = revs->max_count;
92 unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
93 ? CE_MATCH_RACY_IS_DIRTY : 0);
94
95 diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
96
97 if (diff_unmerged_stage < 0)
98 diff_unmerged_stage = 2;
99 entries = active_nr;
100 for (i = 0; i < entries; i++) {
101 unsigned int oldmode, newmode;
102 struct cache_entry *ce = active_cache[i];
103 int changed;
104 unsigned dirty_submodule = 0;
105 const struct object_id *old_oid, *new_oid;
106
107 if (diff_can_quit_early(&revs->diffopt))
108 break;
109
110 if (!ce_path_match(ce, &revs->prune_data, NULL))
111 continue;
112
113 if (ce_stage(ce)) {
114 struct combine_diff_path *dpath;
115 struct diff_filepair *pair;
116 unsigned int wt_mode = 0;
117 int num_compare_stages = 0;
118 size_t path_len;
119 struct stat st;
120
121 path_len = ce_namelen(ce);
122
123 dpath = xmalloc(combine_diff_path_size(5, path_len));
124 dpath->path = (char *) &(dpath->parent[5]);
125
126 dpath->next = NULL;
127 memcpy(dpath->path, ce->name, path_len);
128 dpath->path[path_len] = '\0';
129 oidclr(&dpath->oid);
130 memset(&(dpath->parent[0]), 0,
131 sizeof(struct combine_diff_parent)*5);
132
133 changed = check_removed(ce, &st);
134 if (!changed)
135 wt_mode = ce_mode_from_stat(ce, st.st_mode);
136 else {
137 if (changed < 0) {
138 perror(ce->name);
139 continue;
140 }
141 wt_mode = 0;
142 }
143 dpath->mode = wt_mode;
144
145 while (i < entries) {
146 struct cache_entry *nce = active_cache[i];
147 int stage;
148
149 if (strcmp(ce->name, nce->name))
150 break;
151
152 /* Stage #2 (ours) is the first parent,
153 * stage #3 (theirs) is the second.
154 */
155 stage = ce_stage(nce);
156 if (2 <= stage) {
157 int mode = nce->ce_mode;
158 num_compare_stages++;
159 oidcpy(&dpath->parent[stage - 2].oid,
160 &nce->oid);
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_AND_NULL(dpath);
184
185 /*
186 * Show the diff for the 'ce' if we found the one
187 * from the desired stage.
188 */
189 pair = diff_unmerge(&revs->diffopt, ce->name);
190 if (wt_mode)
191 pair->two->mode = wt_mode;
192 if (ce_stage(ce) != diff_unmerged_stage)
193 continue;
194 }
195
196 if (ce_uptodate(ce) || ce_skip_worktree(ce))
197 continue;
198
199 /* If CE_VALID is set, don't look at workdir for file removal */
200 if (ce->ce_flags & CE_VALID) {
201 changed = 0;
202 newmode = ce->ce_mode;
203 } else {
204 struct stat st;
205
206 changed = check_removed(ce, &st);
207 if (changed) {
208 if (changed < 0) {
209 perror(ce->name);
210 continue;
211 }
212 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
213 &ce->oid,
214 !is_null_oid(&ce->oid),
215 ce->name, 0);
216 continue;
217 } else if (revs->diffopt.ita_invisible_in_index &&
218 ce_intent_to_add(ce)) {
219 diff_addremove(&revs->diffopt, '+', ce->ce_mode,
220 &empty_tree_oid, 0,
221 ce->name, 0);
222 continue;
223 }
224
225 changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
226 ce_option, &dirty_submodule);
227 newmode = ce_mode_from_stat(ce, st.st_mode);
228 }
229
230 if (!changed && !dirty_submodule) {
231 ce_mark_uptodate(ce);
232 mark_fsmonitor_valid(ce);
233 if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
234 continue;
235 }
236 oldmode = ce->ce_mode;
237 old_oid = &ce->oid;
238 new_oid = changed ? &null_oid : &ce->oid;
239 diff_change(&revs->diffopt, oldmode, newmode,
240 old_oid, new_oid,
241 !is_null_oid(old_oid),
242 !is_null_oid(new_oid),
243 ce->name, 0, dirty_submodule);
244
245 }
246 diffcore_std(&revs->diffopt);
247 diff_flush(&revs->diffopt);
248 return 0;
249 }
250
251 /*
252 * diff-index
253 */
254
255 /* A file entry went away or appeared */
256 static void diff_index_show_file(struct rev_info *revs,
257 const char *prefix,
258 const struct cache_entry *ce,
259 const struct object_id *oid, int oid_valid,
260 unsigned int mode,
261 unsigned dirty_submodule)
262 {
263 diff_addremove(&revs->diffopt, prefix[0], mode,
264 oid, oid_valid, ce->name, dirty_submodule);
265 }
266
267 static int get_stat_data(const struct cache_entry *ce,
268 const struct object_id **oidp,
269 unsigned int *modep,
270 int cached, int match_missing,
271 unsigned *dirty_submodule, struct diff_options *diffopt)
272 {
273 const struct object_id *oid = &ce->oid;
274 unsigned int mode = ce->ce_mode;
275
276 if (!cached && !ce_uptodate(ce)) {
277 int changed;
278 struct stat st;
279 changed = check_removed(ce, &st);
280 if (changed < 0)
281 return -1;
282 else if (changed) {
283 if (match_missing) {
284 *oidp = oid;
285 *modep = mode;
286 return 0;
287 }
288 return -1;
289 }
290 changed = match_stat_with_submodule(diffopt, ce, &st,
291 0, dirty_submodule);
292 if (changed) {
293 mode = ce_mode_from_stat(ce, st.st_mode);
294 oid = &null_oid;
295 }
296 }
297
298 *oidp = oid;
299 *modep = mode;
300 return 0;
301 }
302
303 static void show_new_file(struct rev_info *revs,
304 const struct cache_entry *new,
305 int cached, int match_missing)
306 {
307 const struct object_id *oid;
308 unsigned int mode;
309 unsigned dirty_submodule = 0;
310
311 /*
312 * New file in the index: it might actually be different in
313 * the working tree.
314 */
315 if (get_stat_data(new, &oid, &mode, cached, match_missing,
316 &dirty_submodule, &revs->diffopt) < 0)
317 return;
318
319 diff_index_show_file(revs, "+", new, oid, !is_null_oid(oid), mode, dirty_submodule);
320 }
321
322 static int show_modified(struct rev_info *revs,
323 const struct cache_entry *old,
324 const struct cache_entry *new,
325 int report_missing,
326 int cached, int match_missing)
327 {
328 unsigned int mode, oldmode;
329 const struct object_id *oid;
330 unsigned dirty_submodule = 0;
331
332 if (get_stat_data(new, &oid, &mode, cached, match_missing,
333 &dirty_submodule, &revs->diffopt) < 0) {
334 if (report_missing)
335 diff_index_show_file(revs, "-", old,
336 &old->oid, 1, old->ce_mode,
337 0);
338 return -1;
339 }
340
341 if (revs->combine_merges && !cached &&
342 (oidcmp(oid, &old->oid) || oidcmp(&old->oid, &new->oid))) {
343 struct combine_diff_path *p;
344 int pathlen = ce_namelen(new);
345
346 p = xmalloc(combine_diff_path_size(2, pathlen));
347 p->path = (char *) &p->parent[2];
348 p->next = NULL;
349 memcpy(p->path, new->name, pathlen);
350 p->path[pathlen] = 0;
351 p->mode = mode;
352 oidclr(&p->oid);
353 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
354 p->parent[0].status = DIFF_STATUS_MODIFIED;
355 p->parent[0].mode = new->ce_mode;
356 oidcpy(&p->parent[0].oid, &new->oid);
357 p->parent[1].status = DIFF_STATUS_MODIFIED;
358 p->parent[1].mode = old->ce_mode;
359 oidcpy(&p->parent[1].oid, &old->oid);
360 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
361 free(p);
362 return 0;
363 }
364
365 oldmode = old->ce_mode;
366 if (mode == oldmode && !oidcmp(oid, &old->oid) && !dirty_submodule &&
367 !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
368 return 0;
369
370 diff_change(&revs->diffopt, oldmode, mode,
371 &old->oid, oid, 1, !is_null_oid(oid),
372 old->name, 0, dirty_submodule);
373 return 0;
374 }
375
376 /*
377 * This gets a mix of an existing index and a tree, one pathname entry
378 * at a time. The index entry may be a single stage-0 one, but it could
379 * also be multiple unmerged entries (in which case idx_pos/idx_nr will
380 * give you the position and number of entries in the index).
381 */
382 static void do_oneway_diff(struct unpack_trees_options *o,
383 const struct cache_entry *idx,
384 const struct cache_entry *tree)
385 {
386 struct rev_info *revs = o->unpack_data;
387 int match_missing, cached;
388
389 /* i-t-a entries do not actually exist in the index */
390 if (revs->diffopt.ita_invisible_in_index &&
391 idx && ce_intent_to_add(idx)) {
392 idx = NULL;
393 if (!tree)
394 return; /* nothing to diff.. */
395 }
396
397 /* if the entry is not checked out, don't examine work tree */
398 cached = o->index_only ||
399 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
400 /*
401 * Backward compatibility wart - "diff-index -m" does
402 * not mean "do not ignore merges", but "match_missing".
403 *
404 * But with the revision flag parsing, that's found in
405 * "!revs->ignore_merges".
406 */
407 match_missing = !revs->ignore_merges;
408
409 if (cached && idx && ce_stage(idx)) {
410 struct diff_filepair *pair;
411 pair = diff_unmerge(&revs->diffopt, idx->name);
412 if (tree)
413 fill_filespec(pair->one, &tree->oid, 1,
414 tree->ce_mode);
415 return;
416 }
417
418 /*
419 * Something added to the tree?
420 */
421 if (!tree) {
422 show_new_file(revs, idx, cached, match_missing);
423 return;
424 }
425
426 /*
427 * Something removed from the tree?
428 */
429 if (!idx) {
430 diff_index_show_file(revs, "-", tree, &tree->oid, 1,
431 tree->ce_mode, 0);
432 return;
433 }
434
435 /* Show difference between old and new */
436 show_modified(revs, tree, idx, 1, cached, match_missing);
437 }
438
439 /*
440 * The unpack_trees() interface is designed for merging, so
441 * the different source entries are designed primarily for
442 * the source trees, with the old index being really mainly
443 * used for being replaced by the result.
444 *
445 * For diffing, the index is more important, and we only have a
446 * single tree.
447 *
448 * We're supposed to advance o->pos to skip what we have already processed.
449 *
450 * This wrapper makes it all more readable, and takes care of all
451 * the fairly complex unpack_trees() semantic requirements, including
452 * the skipping, the path matching, the type conflict cases etc.
453 */
454 static int oneway_diff(const struct cache_entry * const *src,
455 struct unpack_trees_options *o)
456 {
457 const struct cache_entry *idx = src[0];
458 const struct cache_entry *tree = src[1];
459 struct rev_info *revs = o->unpack_data;
460
461 /*
462 * Unpack-trees generates a DF/conflict entry if
463 * there was a directory in the index and a tree
464 * in the tree. From a diff standpoint, that's a
465 * delete of the tree and a create of the file.
466 */
467 if (tree == o->df_conflict_entry)
468 tree = NULL;
469
470 if (ce_path_match(idx ? idx : tree, &revs->prune_data, NULL)) {
471 do_oneway_diff(o, idx, tree);
472 if (diff_can_quit_early(&revs->diffopt)) {
473 o->exiting_early = 1;
474 return -1;
475 }
476 }
477
478 return 0;
479 }
480
481 static int diff_cache(struct rev_info *revs,
482 const struct object_id *tree_oid,
483 const char *tree_name,
484 int cached)
485 {
486 struct tree *tree;
487 struct tree_desc t;
488 struct unpack_trees_options opts;
489
490 tree = parse_tree_indirect(tree_oid);
491 if (!tree)
492 return error("bad tree object %s",
493 tree_name ? tree_name : oid_to_hex(tree_oid));
494 memset(&opts, 0, sizeof(opts));
495 opts.head_idx = 1;
496 opts.index_only = cached;
497 opts.diff_index_cached = (cached &&
498 !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
499 opts.merge = 1;
500 opts.fn = oneway_diff;
501 opts.unpack_data = revs;
502 opts.src_index = &the_index;
503 opts.dst_index = NULL;
504 opts.pathspec = &revs->diffopt.pathspec;
505 opts.pathspec->recursive = 1;
506
507 init_tree_desc(&t, tree->buffer, tree->size);
508 return unpack_trees(1, &t, &opts);
509 }
510
511 int run_diff_index(struct rev_info *revs, int cached)
512 {
513 struct object_array_entry *ent;
514
515 ent = revs->pending.objects;
516 if (diff_cache(revs, &ent->item->oid, ent->name, cached))
517 exit(128);
518
519 diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
520 diffcore_fix_diff_index(&revs->diffopt);
521 diffcore_std(&revs->diffopt);
522 diff_flush(&revs->diffopt);
523 return 0;
524 }
525
526 int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
527 {
528 struct rev_info revs;
529
530 init_revisions(&revs, NULL);
531 copy_pathspec(&revs.prune_data, &opt->pathspec);
532 revs.diffopt = *opt;
533
534 if (diff_cache(&revs, tree_oid, NULL, 1))
535 exit(128);
536 return 0;
537 }
538
539 int index_differs_from(const char *def, int diff_flags,
540 int ita_invisible_in_index)
541 {
542 struct rev_info rev;
543 struct setup_revision_opt opt;
544
545 init_revisions(&rev, NULL);
546 memset(&opt, 0, sizeof(opt));
547 opt.def = def;
548 setup_revisions(0, NULL, &rev, &opt);
549 DIFF_OPT_SET(&rev.diffopt, QUICK);
550 DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
551 rev.diffopt.flags |= diff_flags;
552 rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
553 run_diff_index(&rev, 1);
554 if (rev.pending.alloc)
555 free(rev.pending.objects);
556 return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
557 }