Avoid unnecessary 'lstat()' calls in 'get_stat_data()'
[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
14 /*
15 * diff-files
16 */
17
18 /*
19 * Has the work tree entity been removed?
20 *
21 * Return 1 if it was removed from the work tree, 0 if an entity to be
22 * compared with the cache entry ce still exists (the latter includes
23 * the case where a directory that is not a submodule repository
24 * exists for ce that is a submodule -- it is a submodule that is not
25 * checked out). Return negative for an error.
26 */
27 static int check_removed(const struct cache_entry *ce, struct stat *st)
28 {
29 if (lstat(ce->name, st) < 0) {
30 if (errno != ENOENT && errno != ENOTDIR)
31 return -1;
32 return 1;
33 }
34 if (has_symlink_leading_path(ce_namelen(ce), ce->name))
35 return 1;
36 if (S_ISDIR(st->st_mode)) {
37 unsigned char sub[20];
38
39 /*
40 * If ce is already a gitlink, we can have a plain
41 * directory (i.e. the submodule is not checked out),
42 * or a checked out submodule. Either case this is not
43 * a case where something was removed from the work tree,
44 * so we will return 0.
45 *
46 * Otherwise, if the directory is not a submodule
47 * repository, that means ce which was a blob turned into
48 * a directory --- the blob was removed!
49 */
50 if (!S_ISGITLINK(ce->ce_mode) &&
51 resolve_gitlink_ref(ce->name, "HEAD", sub))
52 return 1;
53 }
54 return 0;
55 }
56
57 int run_diff_files(struct rev_info *revs, unsigned int option)
58 {
59 int entries, i;
60 int diff_unmerged_stage = revs->max_count;
61 int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
62 unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
63 ? CE_MATCH_RACY_IS_DIRTY : 0);
64 char symcache[PATH_MAX];
65
66 diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
67
68 if (diff_unmerged_stage < 0)
69 diff_unmerged_stage = 2;
70 entries = active_nr;
71 symcache[0] = '\0';
72 for (i = 0; i < entries; i++) {
73 struct stat st;
74 unsigned int oldmode, newmode;
75 struct cache_entry *ce = active_cache[i];
76 int changed;
77
78 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
79 DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
80 break;
81
82 if (!ce_path_match(ce, revs->prune_data))
83 continue;
84
85 if (ce_stage(ce)) {
86 struct combine_diff_path *dpath;
87 int num_compare_stages = 0;
88 size_t path_len;
89
90 path_len = ce_namelen(ce);
91
92 dpath = xmalloc(combine_diff_path_size(5, path_len));
93 dpath->path = (char *) &(dpath->parent[5]);
94
95 dpath->next = NULL;
96 dpath->len = path_len;
97 memcpy(dpath->path, ce->name, path_len);
98 dpath->path[path_len] = '\0';
99 hashclr(dpath->sha1);
100 memset(&(dpath->parent[0]), 0,
101 sizeof(struct combine_diff_parent)*5);
102
103 changed = check_removed(ce, &st);
104 if (!changed)
105 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
106 else {
107 if (changed < 0) {
108 perror(ce->name);
109 continue;
110 }
111 if (silent_on_removed)
112 continue;
113 }
114
115 while (i < entries) {
116 struct cache_entry *nce = active_cache[i];
117 int stage;
118
119 if (strcmp(ce->name, nce->name))
120 break;
121
122 /* Stage #2 (ours) is the first parent,
123 * stage #3 (theirs) is the second.
124 */
125 stage = ce_stage(nce);
126 if (2 <= stage) {
127 int mode = nce->ce_mode;
128 num_compare_stages++;
129 hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
130 dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
131 dpath->parent[stage-2].status =
132 DIFF_STATUS_MODIFIED;
133 }
134
135 /* diff against the proper unmerged stage */
136 if (stage == diff_unmerged_stage)
137 ce = nce;
138 i++;
139 }
140 /*
141 * Compensate for loop update
142 */
143 i--;
144
145 if (revs->combine_merges && num_compare_stages == 2) {
146 show_combined_diff(dpath, 2,
147 revs->dense_combined_merges,
148 revs);
149 free(dpath);
150 continue;
151 }
152 free(dpath);
153 dpath = NULL;
154
155 /*
156 * Show the diff for the 'ce' if we found the one
157 * from the desired stage.
158 */
159 diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
160 if (ce_stage(ce) != diff_unmerged_stage)
161 continue;
162 }
163
164 if (ce_uptodate(ce))
165 continue;
166
167 changed = check_removed(ce, &st);
168 if (changed) {
169 if (changed < 0) {
170 perror(ce->name);
171 continue;
172 }
173 if (silent_on_removed)
174 continue;
175 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
176 ce->sha1, ce->name);
177 continue;
178 }
179 changed = ce_match_stat(ce, &st, ce_option);
180 if (!changed) {
181 ce_mark_uptodate(ce);
182 if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
183 continue;
184 }
185 oldmode = ce->ce_mode;
186 newmode = ce_mode_from_stat(ce, st.st_mode);
187 diff_change(&revs->diffopt, oldmode, newmode,
188 ce->sha1, (changed ? null_sha1 : ce->sha1),
189 ce->name);
190
191 }
192 diffcore_std(&revs->diffopt);
193 diff_flush(&revs->diffopt);
194 return 0;
195 }
196
197 /*
198 * diff-index
199 */
200
201 struct oneway_unpack_data {
202 struct rev_info *revs;
203 char symcache[PATH_MAX];
204 };
205
206 /* A file entry went away or appeared */
207 static void diff_index_show_file(struct rev_info *revs,
208 const char *prefix,
209 struct cache_entry *ce,
210 const unsigned char *sha1, unsigned int mode)
211 {
212 diff_addremove(&revs->diffopt, prefix[0], mode,
213 sha1, ce->name);
214 }
215
216 static int get_stat_data(struct cache_entry *ce,
217 const unsigned char **sha1p,
218 unsigned int *modep,
219 int cached, int match_missing,
220 struct oneway_unpack_data *cbdata)
221 {
222 const unsigned char *sha1 = ce->sha1;
223 unsigned int mode = ce->ce_mode;
224
225 if (!cached && !ce_uptodate(ce)) {
226 int changed;
227 struct stat st;
228 changed = check_removed(ce, &st);
229 if (changed < 0)
230 return -1;
231 else if (changed) {
232 if (match_missing) {
233 *sha1p = sha1;
234 *modep = mode;
235 return 0;
236 }
237 return -1;
238 }
239 changed = ce_match_stat(ce, &st, 0);
240 if (changed) {
241 mode = ce_mode_from_stat(ce, st.st_mode);
242 sha1 = null_sha1;
243 }
244 }
245
246 *sha1p = sha1;
247 *modep = mode;
248 return 0;
249 }
250
251 static void show_new_file(struct oneway_unpack_data *cbdata,
252 struct cache_entry *new,
253 int cached, int match_missing)
254 {
255 const unsigned char *sha1;
256 unsigned int mode;
257 struct rev_info *revs = cbdata->revs;
258
259 /*
260 * New file in the index: it might actually be different in
261 * the working copy.
262 */
263 if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0)
264 return;
265
266 diff_index_show_file(revs, "+", new, sha1, mode);
267 }
268
269 static int show_modified(struct oneway_unpack_data *cbdata,
270 struct cache_entry *old,
271 struct cache_entry *new,
272 int report_missing,
273 int cached, int match_missing)
274 {
275 unsigned int mode, oldmode;
276 const unsigned char *sha1;
277 struct rev_info *revs = cbdata->revs;
278
279 if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0) {
280 if (report_missing)
281 diff_index_show_file(revs, "-", old,
282 old->sha1, old->ce_mode);
283 return -1;
284 }
285
286 if (revs->combine_merges && !cached &&
287 (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
288 struct combine_diff_path *p;
289 int pathlen = ce_namelen(new);
290
291 p = xmalloc(combine_diff_path_size(2, pathlen));
292 p->path = (char *) &p->parent[2];
293 p->next = NULL;
294 p->len = pathlen;
295 memcpy(p->path, new->name, pathlen);
296 p->path[pathlen] = 0;
297 p->mode = mode;
298 hashclr(p->sha1);
299 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
300 p->parent[0].status = DIFF_STATUS_MODIFIED;
301 p->parent[0].mode = new->ce_mode;
302 hashcpy(p->parent[0].sha1, new->sha1);
303 p->parent[1].status = DIFF_STATUS_MODIFIED;
304 p->parent[1].mode = old->ce_mode;
305 hashcpy(p->parent[1].sha1, old->sha1);
306 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
307 free(p);
308 return 0;
309 }
310
311 oldmode = old->ce_mode;
312 if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
313 !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
314 return 0;
315
316 diff_change(&revs->diffopt, oldmode, mode,
317 old->sha1, sha1, old->name);
318 return 0;
319 }
320
321 /*
322 * This turns all merge entries into "stage 3". That guarantees that
323 * when we read in the new tree (into "stage 1"), we won't lose sight
324 * of the fact that we had unmerged entries.
325 */
326 static void mark_merge_entries(void)
327 {
328 int i;
329 for (i = 0; i < active_nr; i++) {
330 struct cache_entry *ce = active_cache[i];
331 if (!ce_stage(ce))
332 continue;
333 ce->ce_flags |= CE_STAGEMASK;
334 }
335 }
336
337 /*
338 * This gets a mix of an existing index and a tree, one pathname entry
339 * at a time. The index entry may be a single stage-0 one, but it could
340 * also be multiple unmerged entries (in which case idx_pos/idx_nr will
341 * give you the position and number of entries in the index).
342 */
343 static void do_oneway_diff(struct unpack_trees_options *o,
344 struct cache_entry *idx,
345 struct cache_entry *tree)
346 {
347 struct oneway_unpack_data *cbdata = o->unpack_data;
348 struct rev_info *revs = cbdata->revs;
349 int match_missing, cached;
350
351 /*
352 * Backward compatibility wart - "diff-index -m" does
353 * not mean "do not ignore merges", but "match_missing".
354 *
355 * But with the revision flag parsing, that's found in
356 * "!revs->ignore_merges".
357 */
358 cached = o->index_only;
359 match_missing = !revs->ignore_merges;
360
361 if (cached && idx && ce_stage(idx)) {
362 if (tree)
363 diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
364 return;
365 }
366
367 /*
368 * Something added to the tree?
369 */
370 if (!tree) {
371 show_new_file(cbdata, idx, cached, match_missing);
372 return;
373 }
374
375 /*
376 * Something removed from the tree?
377 */
378 if (!idx) {
379 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
380 return;
381 }
382
383 /* Show difference between old and new */
384 show_modified(cbdata, tree, idx, 1, cached, match_missing);
385 }
386
387 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
388 {
389 int len = ce_namelen(ce);
390 const struct index_state *index = o->src_index;
391
392 while (o->pos < index->cache_nr) {
393 struct cache_entry *next = index->cache[o->pos];
394 if (len != ce_namelen(next))
395 break;
396 if (memcmp(ce->name, next->name, len))
397 break;
398 o->pos++;
399 }
400 }
401
402 /*
403 * The unpack_trees() interface is designed for merging, so
404 * the different source entries are designed primarily for
405 * the source trees, with the old index being really mainly
406 * used for being replaced by the result.
407 *
408 * For diffing, the index is more important, and we only have a
409 * single tree.
410 *
411 * We're supposed to return how many index entries we want to skip.
412 *
413 * This wrapper makes it all more readable, and takes care of all
414 * the fairly complex unpack_trees() semantic requirements, including
415 * the skipping, the path matching, the type conflict cases etc.
416 */
417 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
418 {
419 struct cache_entry *idx = src[0];
420 struct cache_entry *tree = src[1];
421 struct oneway_unpack_data *cbdata = o->unpack_data;
422 struct rev_info *revs = cbdata->revs;
423
424 if (idx && ce_stage(idx))
425 skip_same_name(idx, o);
426
427 /*
428 * Unpack-trees generates a DF/conflict entry if
429 * there was a directory in the index and a tree
430 * in the tree. From a diff standpoint, that's a
431 * delete of the tree and a create of the file.
432 */
433 if (tree == o->df_conflict_entry)
434 tree = NULL;
435
436 if (ce_path_match(idx ? idx : tree, revs->prune_data))
437 do_oneway_diff(o, idx, tree);
438
439 return 0;
440 }
441
442 int run_diff_index(struct rev_info *revs, int cached)
443 {
444 struct object *ent;
445 struct tree *tree;
446 const char *tree_name;
447 struct unpack_trees_options opts;
448 struct tree_desc t;
449 struct oneway_unpack_data unpack_cb;
450
451 mark_merge_entries();
452
453 ent = revs->pending.objects[0].item;
454 tree_name = revs->pending.objects[0].name;
455 tree = parse_tree_indirect(ent->sha1);
456 if (!tree)
457 return error("bad tree object %s", tree_name);
458
459 unpack_cb.revs = revs;
460 unpack_cb.symcache[0] = '\0';
461 memset(&opts, 0, sizeof(opts));
462 opts.head_idx = 1;
463 opts.index_only = cached;
464 opts.merge = 1;
465 opts.fn = oneway_diff;
466 opts.unpack_data = &unpack_cb;
467 opts.src_index = &the_index;
468 opts.dst_index = NULL;
469
470 init_tree_desc(&t, tree->buffer, tree->size);
471 if (unpack_trees(1, &t, &opts))
472 exit(128);
473
474 diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
475 diffcore_std(&revs->diffopt);
476 diff_flush(&revs->diffopt);
477 return 0;
478 }
479
480 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
481 {
482 struct tree *tree;
483 struct rev_info revs;
484 int i;
485 struct cache_entry **dst;
486 struct cache_entry *last = NULL;
487 struct unpack_trees_options opts;
488 struct tree_desc t;
489 struct oneway_unpack_data unpack_cb;
490
491 /*
492 * This is used by git-blame to run diff-cache internally;
493 * it potentially needs to repeatedly run this, so we will
494 * start by removing the higher order entries the last round
495 * left behind.
496 */
497 dst = active_cache;
498 for (i = 0; i < active_nr; i++) {
499 struct cache_entry *ce = active_cache[i];
500 if (ce_stage(ce)) {
501 if (last && !strcmp(ce->name, last->name))
502 continue;
503 cache_tree_invalidate_path(active_cache_tree,
504 ce->name);
505 last = ce;
506 ce->ce_flags |= CE_REMOVE;
507 }
508 *dst++ = ce;
509 }
510 active_nr = dst - active_cache;
511
512 init_revisions(&revs, NULL);
513 revs.prune_data = opt->paths;
514 tree = parse_tree_indirect(tree_sha1);
515 if (!tree)
516 die("bad tree object %s", sha1_to_hex(tree_sha1));
517
518 unpack_cb.revs = &revs;
519 unpack_cb.symcache[0] = '\0';
520 memset(&opts, 0, sizeof(opts));
521 opts.head_idx = 1;
522 opts.index_only = 1;
523 opts.merge = 1;
524 opts.fn = oneway_diff;
525 opts.unpack_data = &unpack_cb;
526 opts.src_index = &the_index;
527 opts.dst_index = &the_index;
528
529 init_tree_desc(&t, tree->buffer, tree->size);
530 if (unpack_trees(1, &t, &opts))
531 exit(128);
532 return 0;
533 }