make USE_NSEC work as expected
[git/git.git] / unpack-trees.c
1 #define NO_THE_INDEX_COMPATIBILITY_MACROS
2 #include "cache.h"
3 #include "dir.h"
4 #include "tree.h"
5 #include "tree-walk.h"
6 #include "cache-tree.h"
7 #include "unpack-trees.h"
8 #include "progress.h"
9 #include "refs.h"
10
11 /*
12 * Error messages expected by scripts out of plumbing commands such as
13 * read-tree. Non-scripted Porcelain is not required to use these messages
14 * and in fact are encouraged to reword them to better suit their particular
15 * situation better. See how "git checkout" replaces not_uptodate_file to
16 * explain why it does not allow switching between branches when you have
17 * local changes, for example.
18 */
19 static struct unpack_trees_error_msgs unpack_plumbing_errors = {
20 /* would_overwrite */
21 "Entry '%s' would be overwritten by merge. Cannot merge.",
22
23 /* not_uptodate_file */
24 "Entry '%s' not uptodate. Cannot merge.",
25
26 /* not_uptodate_dir */
27 "Updating '%s' would lose untracked files in it",
28
29 /* would_lose_untracked */
30 "Untracked working tree file '%s' would be %s by merge.",
31
32 /* bind_overlap */
33 "Entry '%s' overlaps with '%s'. Cannot bind.",
34 };
35
36 #define ERRORMSG(o,fld) \
37 ( ((o) && (o)->msgs.fld) \
38 ? ((o)->msgs.fld) \
39 : (unpack_plumbing_errors.fld) )
40
41 static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
42 unsigned int set, unsigned int clear)
43 {
44 unsigned int size = ce_size(ce);
45 struct cache_entry *new = xmalloc(size);
46
47 clear |= CE_HASHED | CE_UNHASHED;
48
49 memcpy(new, ce, size);
50 new->next = NULL;
51 new->ce_flags = (new->ce_flags & ~clear) | set;
52 add_index_entry(&o->result, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|ADD_CACHE_SKIP_DFCHECK);
53 }
54
55 /*
56 * Unlink the last component and schedule the leading directories for
57 * removal, such that empty directories get removed.
58 */
59 static void unlink_entry(struct cache_entry *ce)
60 {
61 if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
62 return;
63 if (unlink(ce->name))
64 return;
65 schedule_dir_for_removal(ce->name, ce_namelen(ce));
66 }
67
68 static struct checkout state;
69 static int check_updates(struct unpack_trees_options *o)
70 {
71 unsigned cnt = 0, total = 0;
72 struct progress *progress = NULL;
73 struct index_state *index = &o->result;
74 int i;
75 int errs = 0;
76
77 if (o->update && o->verbose_update) {
78 for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
79 struct cache_entry *ce = index->cache[cnt];
80 if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
81 total++;
82 }
83
84 progress = start_progress_delay("Checking out files",
85 total, 50, 1);
86 cnt = 0;
87 }
88
89 for (i = 0; i < index->cache_nr; i++) {
90 struct cache_entry *ce = index->cache[i];
91
92 if (ce->ce_flags & CE_REMOVE) {
93 display_progress(progress, ++cnt);
94 if (o->update)
95 unlink_entry(ce);
96 }
97 }
98 remove_marked_cache_entries(&o->result);
99 remove_scheduled_dirs();
100
101 for (i = 0; i < index->cache_nr; i++) {
102 struct cache_entry *ce = index->cache[i];
103
104 if (ce->ce_flags & CE_UPDATE) {
105 display_progress(progress, ++cnt);
106 ce->ce_flags &= ~CE_UPDATE;
107 if (o->update) {
108 errs |= checkout_entry(ce, &state, NULL);
109 }
110 }
111 }
112 stop_progress(&progress);
113 return errs != 0;
114 }
115
116 static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_options *o)
117 {
118 int ret = o->fn(src, o);
119 if (ret > 0)
120 ret = 0;
121 return ret;
122 }
123
124 static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
125 {
126 struct cache_entry *src[5] = { ce, };
127
128 o->pos++;
129 if (ce_stage(ce)) {
130 if (o->skip_unmerged) {
131 add_entry(o, ce, 0, 0);
132 return 0;
133 }
134 }
135 return call_unpack_fn(src, o);
136 }
137
138 int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
139 {
140 int i;
141 struct tree_desc t[MAX_UNPACK_TREES];
142 struct traverse_info newinfo;
143 struct name_entry *p;
144
145 p = names;
146 while (!p->mode)
147 p++;
148
149 newinfo = *info;
150 newinfo.prev = info;
151 newinfo.name = *p;
152 newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
153 newinfo.conflicts |= df_conflicts;
154
155 for (i = 0; i < n; i++, dirmask >>= 1) {
156 const unsigned char *sha1 = NULL;
157 if (dirmask & 1)
158 sha1 = names[i].sha1;
159 fill_tree_descriptor(t+i, sha1);
160 }
161 return traverse_trees(n, t, &newinfo);
162 }
163
164 /*
165 * Compare the traverse-path to the cache entry without actually
166 * having to generate the textual representation of the traverse
167 * path.
168 *
169 * NOTE! This *only* compares up to the size of the traverse path
170 * itself - the caller needs to do the final check for the cache
171 * entry having more data at the end!
172 */
173 static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
174 {
175 int len, pathlen, ce_len;
176 const char *ce_name;
177
178 if (info->prev) {
179 int cmp = do_compare_entry(ce, info->prev, &info->name);
180 if (cmp)
181 return cmp;
182 }
183 pathlen = info->pathlen;
184 ce_len = ce_namelen(ce);
185
186 /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
187 if (ce_len < pathlen)
188 return -1;
189
190 ce_len -= pathlen;
191 ce_name = ce->name + pathlen;
192
193 len = tree_entry_len(n->path, n->sha1);
194 return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
195 }
196
197 static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
198 {
199 int cmp = do_compare_entry(ce, info, n);
200 if (cmp)
201 return cmp;
202
203 /*
204 * Even if the beginning compared identically, the ce should
205 * compare as bigger than a directory leading up to it!
206 */
207 return ce_namelen(ce) > traverse_path_len(info, n);
208 }
209
210 static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
211 {
212 int len = traverse_path_len(info, n);
213 struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
214
215 ce->ce_mode = create_ce_mode(n->mode);
216 ce->ce_flags = create_ce_flags(len, stage);
217 hashcpy(ce->sha1, n->sha1);
218 make_traverse_path(ce->name, info, n);
219
220 return ce;
221 }
222
223 static int unpack_nondirectories(int n, unsigned long mask,
224 unsigned long dirmask,
225 struct cache_entry **src,
226 const struct name_entry *names,
227 const struct traverse_info *info)
228 {
229 int i;
230 struct unpack_trees_options *o = info->data;
231 unsigned long conflicts;
232
233 /* Do we have *only* directories? Nothing to do */
234 if (mask == dirmask && !src[0])
235 return 0;
236
237 conflicts = info->conflicts;
238 if (o->merge)
239 conflicts >>= 1;
240 conflicts |= dirmask;
241
242 /*
243 * Ok, we've filled in up to any potential index entry in src[0],
244 * now do the rest.
245 */
246 for (i = 0; i < n; i++) {
247 int stage;
248 unsigned int bit = 1ul << i;
249 if (conflicts & bit) {
250 src[i + o->merge] = o->df_conflict_entry;
251 continue;
252 }
253 if (!(mask & bit))
254 continue;
255 if (!o->merge)
256 stage = 0;
257 else if (i + 1 < o->head_idx)
258 stage = 1;
259 else if (i + 1 > o->head_idx)
260 stage = 3;
261 else
262 stage = 2;
263 src[i + o->merge] = create_ce_entry(info, names + i, stage);
264 }
265
266 if (o->merge)
267 return call_unpack_fn(src, o);
268
269 n += o->merge;
270 for (i = 0; i < n; i++)
271 add_entry(o, src[i], 0, 0);
272 return 0;
273 }
274
275 static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
276 {
277 struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
278 struct unpack_trees_options *o = info->data;
279 const struct name_entry *p = names;
280
281 /* Find first entry with a real name (we could use "mask" too) */
282 while (!p->mode)
283 p++;
284
285 /* Are we supposed to look at the index too? */
286 if (o->merge) {
287 while (o->pos < o->src_index->cache_nr) {
288 struct cache_entry *ce = o->src_index->cache[o->pos];
289 int cmp = compare_entry(ce, info, p);
290 if (cmp < 0) {
291 if (unpack_index_entry(ce, o) < 0)
292 return -1;
293 continue;
294 }
295 if (!cmp) {
296 o->pos++;
297 if (ce_stage(ce)) {
298 /*
299 * If we skip unmerged index entries, we'll skip this
300 * entry *and* the tree entries associated with it!
301 */
302 if (o->skip_unmerged) {
303 add_entry(o, ce, 0, 0);
304 return mask;
305 }
306 }
307 src[0] = ce;
308 }
309 break;
310 }
311 }
312
313 if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
314 return -1;
315
316 /* Now handle any directories.. */
317 if (dirmask) {
318 unsigned long conflicts = mask & ~dirmask;
319 if (o->merge) {
320 conflicts <<= 1;
321 if (src[0])
322 conflicts |= 1;
323 }
324 if (traverse_trees_recursive(n, dirmask, conflicts,
325 names, info) < 0)
326 return -1;
327 return mask;
328 }
329
330 return mask;
331 }
332
333 static int unpack_failed(struct unpack_trees_options *o, const char *message)
334 {
335 discard_index(&o->result);
336 if (!o->gently) {
337 if (message)
338 return error("%s", message);
339 return -1;
340 }
341 return -1;
342 }
343
344 /*
345 * N-way merge "len" trees. Returns 0 on success, -1 on failure to manipulate the
346 * resulting index, -2 on failure to reflect the changes to the work tree.
347 */
348 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
349 {
350 int ret;
351 static struct cache_entry *dfc;
352
353 if (len > MAX_UNPACK_TREES)
354 die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
355 memset(&state, 0, sizeof(state));
356 state.base_dir = "";
357 state.force = 1;
358 state.quiet = 1;
359 state.refresh_cache = 1;
360
361 memset(&o->result, 0, sizeof(o->result));
362 o->result.initialized = 1;
363 if (o->src_index) {
364 o->result.timestamp.sec = o->src_index->timestamp.sec;
365 #ifdef USE_NSEC
366 o->result.timestamp.nsec = o->src_index->timestamp.nsec;
367 #endif
368 }
369 o->merge_size = len;
370
371 if (!dfc)
372 dfc = xcalloc(1, cache_entry_size(0));
373 o->df_conflict_entry = dfc;
374
375 if (len) {
376 const char *prefix = o->prefix ? o->prefix : "";
377 struct traverse_info info;
378
379 setup_traverse_info(&info, prefix);
380 info.fn = unpack_callback;
381 info.data = o;
382
383 if (traverse_trees(len, t, &info) < 0)
384 return unpack_failed(o, NULL);
385 }
386
387 /* Any left-over entries in the index? */
388 if (o->merge) {
389 while (o->pos < o->src_index->cache_nr) {
390 struct cache_entry *ce = o->src_index->cache[o->pos];
391 if (unpack_index_entry(ce, o) < 0)
392 return unpack_failed(o, NULL);
393 }
394 }
395
396 if (o->trivial_merges_only && o->nontrivial_merge)
397 return unpack_failed(o, "Merge requires file-level merging");
398
399 o->src_index = NULL;
400 ret = check_updates(o) ? (-2) : 0;
401 if (o->dst_index)
402 *o->dst_index = o->result;
403 return ret;
404 }
405
406 /* Here come the merge functions */
407
408 static int reject_merge(struct cache_entry *ce, struct unpack_trees_options *o)
409 {
410 return error(ERRORMSG(o, would_overwrite), ce->name);
411 }
412
413 static int same(struct cache_entry *a, struct cache_entry *b)
414 {
415 if (!!a != !!b)
416 return 0;
417 if (!a && !b)
418 return 1;
419 return a->ce_mode == b->ce_mode &&
420 !hashcmp(a->sha1, b->sha1);
421 }
422
423
424 /*
425 * When a CE gets turned into an unmerged entry, we
426 * want it to be up-to-date
427 */
428 static int verify_uptodate(struct cache_entry *ce,
429 struct unpack_trees_options *o)
430 {
431 struct stat st;
432
433 if (o->index_only || o->reset)
434 return 0;
435
436 if (!lstat(ce->name, &st)) {
437 unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID);
438 if (!changed)
439 return 0;
440 /*
441 * NEEDSWORK: the current default policy is to allow
442 * submodule to be out of sync wrt the supermodule
443 * index. This needs to be tightened later for
444 * submodules that are marked to be automatically
445 * checked out.
446 */
447 if (S_ISGITLINK(ce->ce_mode))
448 return 0;
449 errno = 0;
450 }
451 if (errno == ENOENT)
452 return 0;
453 return o->gently ? -1 :
454 error(ERRORMSG(o, not_uptodate_file), ce->name);
455 }
456
457 static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
458 {
459 if (ce)
460 cache_tree_invalidate_path(o->src_index->cache_tree, ce->name);
461 }
462
463 /*
464 * Check that checking out ce->sha1 in subdir ce->name is not
465 * going to overwrite any working files.
466 *
467 * Currently, git does not checkout subprojects during a superproject
468 * checkout, so it is not going to overwrite anything.
469 */
470 static int verify_clean_submodule(struct cache_entry *ce, const char *action,
471 struct unpack_trees_options *o)
472 {
473 return 0;
474 }
475
476 static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
477 struct unpack_trees_options *o)
478 {
479 /*
480 * we are about to extract "ce->name"; we would not want to lose
481 * anything in the existing directory there.
482 */
483 int namelen;
484 int i;
485 struct dir_struct d;
486 char *pathbuf;
487 int cnt = 0;
488 unsigned char sha1[20];
489
490 if (S_ISGITLINK(ce->ce_mode) &&
491 resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
492 /* If we are not going to update the submodule, then
493 * we don't care.
494 */
495 if (!hashcmp(sha1, ce->sha1))
496 return 0;
497 return verify_clean_submodule(ce, action, o);
498 }
499
500 /*
501 * First let's make sure we do not have a local modification
502 * in that directory.
503 */
504 namelen = strlen(ce->name);
505 for (i = o->pos; i < o->src_index->cache_nr; i++) {
506 struct cache_entry *ce2 = o->src_index->cache[i];
507 int len = ce_namelen(ce2);
508 if (len < namelen ||
509 strncmp(ce->name, ce2->name, namelen) ||
510 ce2->name[namelen] != '/')
511 break;
512 /*
513 * ce2->name is an entry in the subdirectory.
514 */
515 if (!ce_stage(ce2)) {
516 if (verify_uptodate(ce2, o))
517 return -1;
518 add_entry(o, ce2, CE_REMOVE, 0);
519 }
520 cnt++;
521 }
522
523 /*
524 * Then we need to make sure that we do not lose a locally
525 * present file that is not ignored.
526 */
527 pathbuf = xmalloc(namelen + 2);
528 memcpy(pathbuf, ce->name, namelen);
529 strcpy(pathbuf+namelen, "/");
530
531 memset(&d, 0, sizeof(d));
532 if (o->dir)
533 d.exclude_per_dir = o->dir->exclude_per_dir;
534 i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
535 if (i)
536 return o->gently ? -1 :
537 error(ERRORMSG(o, not_uptodate_dir), ce->name);
538 free(pathbuf);
539 return cnt;
540 }
541
542 /*
543 * This gets called when there was no index entry for the tree entry 'dst',
544 * but we found a file in the working tree that 'lstat()' said was fine,
545 * and we're on a case-insensitive filesystem.
546 *
547 * See if we can find a case-insensitive match in the index that also
548 * matches the stat information, and assume it's that other file!
549 */
550 static int icase_exists(struct unpack_trees_options *o, struct cache_entry *dst, struct stat *st)
551 {
552 struct cache_entry *src;
553
554 src = index_name_exists(o->src_index, dst->name, ce_namelen(dst), 1);
555 return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID);
556 }
557
558 /*
559 * We do not want to remove or overwrite a working tree file that
560 * is not tracked, unless it is ignored.
561 */
562 static int verify_absent(struct cache_entry *ce, const char *action,
563 struct unpack_trees_options *o)
564 {
565 struct stat st;
566
567 if (o->index_only || o->reset || !o->update)
568 return 0;
569
570 if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
571 return 0;
572
573 if (!lstat(ce->name, &st)) {
574 int ret;
575 int dtype = ce_to_dtype(ce);
576 struct cache_entry *result;
577
578 /*
579 * It may be that the 'lstat()' succeeded even though
580 * target 'ce' was absent, because there is an old
581 * entry that is different only in case..
582 *
583 * Ignore that lstat() if it matches.
584 */
585 if (ignore_case && icase_exists(o, ce, &st))
586 return 0;
587
588 if (o->dir && excluded(o->dir, ce->name, &dtype))
589 /*
590 * ce->name is explicitly excluded, so it is Ok to
591 * overwrite it.
592 */
593 return 0;
594 if (S_ISDIR(st.st_mode)) {
595 /*
596 * We are checking out path "foo" and
597 * found "foo/." in the working tree.
598 * This is tricky -- if we have modified
599 * files that are in "foo/" we would lose
600 * it.
601 */
602 ret = verify_clean_subdirectory(ce, action, o);
603 if (ret < 0)
604 return ret;
605
606 /*
607 * If this removed entries from the index,
608 * what that means is:
609 *
610 * (1) the caller unpack_callback() saw path/foo
611 * in the index, and it has not removed it because
612 * it thinks it is handling 'path' as blob with
613 * D/F conflict;
614 * (2) we will return "ok, we placed a merged entry
615 * in the index" which would cause o->pos to be
616 * incremented by one;
617 * (3) however, original o->pos now has 'path/foo'
618 * marked with "to be removed".
619 *
620 * We need to increment it by the number of
621 * deleted entries here.
622 */
623 o->pos += ret;
624 return 0;
625 }
626
627 /*
628 * The previous round may already have decided to
629 * delete this path, which is in a subdirectory that
630 * is being replaced with a blob.
631 */
632 result = index_name_exists(&o->result, ce->name, ce_namelen(ce), 0);
633 if (result) {
634 if (result->ce_flags & CE_REMOVE)
635 return 0;
636 }
637
638 return o->gently ? -1 :
639 error(ERRORMSG(o, would_lose_untracked), ce->name, action);
640 }
641 return 0;
642 }
643
644 static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
645 struct unpack_trees_options *o)
646 {
647 int update = CE_UPDATE;
648
649 if (old) {
650 /*
651 * See if we can re-use the old CE directly?
652 * That way we get the uptodate stat info.
653 *
654 * This also removes the UPDATE flag on a match; otherwise
655 * we will end up overwriting local changes in the work tree.
656 */
657 if (same(old, merge)) {
658 copy_cache_entry(merge, old);
659 update = 0;
660 } else {
661 if (verify_uptodate(old, o))
662 return -1;
663 invalidate_ce_path(old, o);
664 }
665 }
666 else {
667 if (verify_absent(merge, "overwritten", o))
668 return -1;
669 invalidate_ce_path(merge, o);
670 }
671
672 add_entry(o, merge, update, CE_STAGEMASK);
673 return 1;
674 }
675
676 static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
677 struct unpack_trees_options *o)
678 {
679 /* Did it exist in the index? */
680 if (!old) {
681 if (verify_absent(ce, "removed", o))
682 return -1;
683 return 0;
684 }
685 if (verify_uptodate(old, o))
686 return -1;
687 add_entry(o, ce, CE_REMOVE, 0);
688 invalidate_ce_path(ce, o);
689 return 1;
690 }
691
692 static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
693 {
694 add_entry(o, ce, 0, 0);
695 return 1;
696 }
697
698 #if DBRT_DEBUG
699 static void show_stage_entry(FILE *o,
700 const char *label, const struct cache_entry *ce)
701 {
702 if (!ce)
703 fprintf(o, "%s (missing)\n", label);
704 else
705 fprintf(o, "%s%06o %s %d\t%s\n",
706 label,
707 ce->ce_mode,
708 sha1_to_hex(ce->sha1),
709 ce_stage(ce),
710 ce->name);
711 }
712 #endif
713
714 int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
715 {
716 struct cache_entry *index;
717 struct cache_entry *head;
718 struct cache_entry *remote = stages[o->head_idx + 1];
719 int count;
720 int head_match = 0;
721 int remote_match = 0;
722
723 int df_conflict_head = 0;
724 int df_conflict_remote = 0;
725
726 int any_anc_missing = 0;
727 int no_anc_exists = 1;
728 int i;
729
730 for (i = 1; i < o->head_idx; i++) {
731 if (!stages[i] || stages[i] == o->df_conflict_entry)
732 any_anc_missing = 1;
733 else
734 no_anc_exists = 0;
735 }
736
737 index = stages[0];
738 head = stages[o->head_idx];
739
740 if (head == o->df_conflict_entry) {
741 df_conflict_head = 1;
742 head = NULL;
743 }
744
745 if (remote == o->df_conflict_entry) {
746 df_conflict_remote = 1;
747 remote = NULL;
748 }
749
750 /* First, if there's a #16 situation, note that to prevent #13
751 * and #14.
752 */
753 if (!same(remote, head)) {
754 for (i = 1; i < o->head_idx; i++) {
755 if (same(stages[i], head)) {
756 head_match = i;
757 }
758 if (same(stages[i], remote)) {
759 remote_match = i;
760 }
761 }
762 }
763
764 /* We start with cases where the index is allowed to match
765 * something other than the head: #14(ALT) and #2ALT, where it
766 * is permitted to match the result instead.
767 */
768 /* #14, #14ALT, #2ALT */
769 if (remote && !df_conflict_head && head_match && !remote_match) {
770 if (index && !same(index, remote) && !same(index, head))
771 return o->gently ? -1 : reject_merge(index, o);
772 return merged_entry(remote, index, o);
773 }
774 /*
775 * If we have an entry in the index cache, then we want to
776 * make sure that it matches head.
777 */
778 if (index && !same(index, head))
779 return o->gently ? -1 : reject_merge(index, o);
780
781 if (head) {
782 /* #5ALT, #15 */
783 if (same(head, remote))
784 return merged_entry(head, index, o);
785 /* #13, #3ALT */
786 if (!df_conflict_remote && remote_match && !head_match)
787 return merged_entry(head, index, o);
788 }
789
790 /* #1 */
791 if (!head && !remote && any_anc_missing)
792 return 0;
793
794 /* Under the new "aggressive" rule, we resolve mostly trivial
795 * cases that we historically had git-merge-one-file resolve.
796 */
797 if (o->aggressive) {
798 int head_deleted = !head && !df_conflict_head;
799 int remote_deleted = !remote && !df_conflict_remote;
800 struct cache_entry *ce = NULL;
801
802 if (index)
803 ce = index;
804 else if (head)
805 ce = head;
806 else if (remote)
807 ce = remote;
808 else {
809 for (i = 1; i < o->head_idx; i++) {
810 if (stages[i] && stages[i] != o->df_conflict_entry) {
811 ce = stages[i];
812 break;
813 }
814 }
815 }
816
817 /*
818 * Deleted in both.
819 * Deleted in one and unchanged in the other.
820 */
821 if ((head_deleted && remote_deleted) ||
822 (head_deleted && remote && remote_match) ||
823 (remote_deleted && head && head_match)) {
824 if (index)
825 return deleted_entry(index, index, o);
826 if (ce && !head_deleted) {
827 if (verify_absent(ce, "removed", o))
828 return -1;
829 }
830 return 0;
831 }
832 /*
833 * Added in both, identically.
834 */
835 if (no_anc_exists && head && remote && same(head, remote))
836 return merged_entry(head, index, o);
837
838 }
839
840 /* Below are "no merge" cases, which require that the index be
841 * up-to-date to avoid the files getting overwritten with
842 * conflict resolution files.
843 */
844 if (index) {
845 if (verify_uptodate(index, o))
846 return -1;
847 }
848
849 o->nontrivial_merge = 1;
850
851 /* #2, #3, #4, #6, #7, #9, #10, #11. */
852 count = 0;
853 if (!head_match || !remote_match) {
854 for (i = 1; i < o->head_idx; i++) {
855 if (stages[i] && stages[i] != o->df_conflict_entry) {
856 keep_entry(stages[i], o);
857 count++;
858 break;
859 }
860 }
861 }
862 #if DBRT_DEBUG
863 else {
864 fprintf(stderr, "read-tree: warning #16 detected\n");
865 show_stage_entry(stderr, "head ", stages[head_match]);
866 show_stage_entry(stderr, "remote ", stages[remote_match]);
867 }
868 #endif
869 if (head) { count += keep_entry(head, o); }
870 if (remote) { count += keep_entry(remote, o); }
871 return count;
872 }
873
874 /*
875 * Two-way merge.
876 *
877 * The rule is to "carry forward" what is in the index without losing
878 * information across a "fast forward", favoring a successful merge
879 * over a merge failure when it makes sense. For details of the
880 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
881 *
882 */
883 int twoway_merge(struct cache_entry **src, struct unpack_trees_options *o)
884 {
885 struct cache_entry *current = src[0];
886 struct cache_entry *oldtree = src[1];
887 struct cache_entry *newtree = src[2];
888
889 if (o->merge_size != 2)
890 return error("Cannot do a twoway merge of %d trees",
891 o->merge_size);
892
893 if (oldtree == o->df_conflict_entry)
894 oldtree = NULL;
895 if (newtree == o->df_conflict_entry)
896 newtree = NULL;
897
898 if (current) {
899 if ((!oldtree && !newtree) || /* 4 and 5 */
900 (!oldtree && newtree &&
901 same(current, newtree)) || /* 6 and 7 */
902 (oldtree && newtree &&
903 same(oldtree, newtree)) || /* 14 and 15 */
904 (oldtree && newtree &&
905 !same(oldtree, newtree) && /* 18 and 19 */
906 same(current, newtree))) {
907 return keep_entry(current, o);
908 }
909 else if (oldtree && !newtree && same(current, oldtree)) {
910 /* 10 or 11 */
911 return deleted_entry(oldtree, current, o);
912 }
913 else if (oldtree && newtree &&
914 same(current, oldtree) && !same(current, newtree)) {
915 /* 20 or 21 */
916 return merged_entry(newtree, current, o);
917 }
918 else {
919 /* all other failures */
920 if (oldtree)
921 return o->gently ? -1 : reject_merge(oldtree, o);
922 if (current)
923 return o->gently ? -1 : reject_merge(current, o);
924 if (newtree)
925 return o->gently ? -1 : reject_merge(newtree, o);
926 return -1;
927 }
928 }
929 else if (newtree) {
930 if (oldtree && !o->initial_checkout) {
931 /*
932 * deletion of the path was staged;
933 */
934 if (same(oldtree, newtree))
935 return 1;
936 return reject_merge(oldtree, o);
937 }
938 return merged_entry(newtree, current, o);
939 }
940 return deleted_entry(oldtree, current, o);
941 }
942
943 /*
944 * Bind merge.
945 *
946 * Keep the index entries at stage0, collapse stage1 but make sure
947 * stage0 does not have anything there.
948 */
949 int bind_merge(struct cache_entry **src,
950 struct unpack_trees_options *o)
951 {
952 struct cache_entry *old = src[0];
953 struct cache_entry *a = src[1];
954
955 if (o->merge_size != 1)
956 return error("Cannot do a bind merge of %d trees\n",
957 o->merge_size);
958 if (a && old)
959 return o->gently ? -1 :
960 error(ERRORMSG(o, bind_overlap), a->name, old->name);
961 if (!a)
962 return keep_entry(old, o);
963 else
964 return merged_entry(a, NULL, o);
965 }
966
967 /*
968 * One-way merge.
969 *
970 * The rule is:
971 * - take the stat information from stage0, take the data from stage1
972 */
973 int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o)
974 {
975 struct cache_entry *old = src[0];
976 struct cache_entry *a = src[1];
977
978 if (o->merge_size != 1)
979 return error("Cannot do a oneway merge of %d trees",
980 o->merge_size);
981
982 if (!a)
983 return deleted_entry(old, old, o);
984
985 if (old && same(old, a)) {
986 int update = 0;
987 if (o->reset) {
988 struct stat st;
989 if (lstat(old->name, &st) ||
990 ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID))
991 update |= CE_UPDATE;
992 }
993 add_entry(o, old, update, 0);
994 return 0;
995 }
996 return merged_entry(a, old, o);
997 }