273b5da0a256337c3d3973b475e7cfa567cee35a
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 */
19static 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
41static 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 */
59static 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
68static struct checkout state;
69static 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
116static 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
124static 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
138int 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 */
173static 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
197static 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
210static 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
223static 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
275static 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
333static 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 */
348int 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 = o->src_index->timestamp;
365 o->merge_size = len;
366
367 if (!dfc)
368 dfc = xcalloc(1, cache_entry_size(0));
369 o->df_conflict_entry = dfc;
370
371 if (len) {
372 const char *prefix = o->prefix ? o->prefix : "";
373 struct traverse_info info;
374
375 setup_traverse_info(&info, prefix);
376 info.fn = unpack_callback;
377 info.data = o;
378
379 if (traverse_trees(len, t, &info) < 0)
380 return unpack_failed(o, NULL);
381 }
382
383 /* Any left-over entries in the index? */
384 if (o->merge) {
385 while (o->pos < o->src_index->cache_nr) {
386 struct cache_entry *ce = o->src_index->cache[o->pos];
387 if (unpack_index_entry(ce, o) < 0)
388 return unpack_failed(o, NULL);
389 }
390 }
391
392 if (o->trivial_merges_only && o->nontrivial_merge)
393 return unpack_failed(o, "Merge requires file-level merging");
394
395 o->src_index = NULL;
396 ret = check_updates(o) ? (-2) : 0;
397 if (o->dst_index)
398 *o->dst_index = o->result;
399 return ret;
400}
401
402/* Here come the merge functions */
403
404static int reject_merge(struct cache_entry *ce, struct unpack_trees_options *o)
405{
406 return error(ERRORMSG(o, would_overwrite), ce->name);
407}
408
409static int same(struct cache_entry *a, struct cache_entry *b)
410{
411 if (!!a != !!b)
412 return 0;
413 if (!a && !b)
414 return 1;
415 return a->ce_mode == b->ce_mode &&
416 !hashcmp(a->sha1, b->sha1);
417}
418
419
420/*
421 * When a CE gets turned into an unmerged entry, we
422 * want it to be up-to-date
423 */
424static int verify_uptodate(struct cache_entry *ce,
425 struct unpack_trees_options *o)
426{
427 struct stat st;
428
429 if (o->index_only || o->reset)
430 return 0;
431
432 if (!lstat(ce->name, &st)) {
433 unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID);
434 if (!changed)
435 return 0;
436 /*
437 * NEEDSWORK: the current default policy is to allow
438 * submodule to be out of sync wrt the supermodule
439 * index. This needs to be tightened later for
440 * submodules that are marked to be automatically
441 * checked out.
442 */
443 if (S_ISGITLINK(ce->ce_mode))
444 return 0;
445 errno = 0;
446 }
447 if (errno == ENOENT)
448 return 0;
449 return o->gently ? -1 :
450 error(ERRORMSG(o, not_uptodate_file), ce->name);
451}
452
453static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
454{
455 if (ce)
456 cache_tree_invalidate_path(o->src_index->cache_tree, ce->name);
457}
458
459/*
460 * Check that checking out ce->sha1 in subdir ce->name is not
461 * going to overwrite any working files.
462 *
463 * Currently, git does not checkout subprojects during a superproject
464 * checkout, so it is not going to overwrite anything.
465 */
466static int verify_clean_submodule(struct cache_entry *ce, const char *action,
467 struct unpack_trees_options *o)
468{
469 return 0;
470}
471
472static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
473 struct unpack_trees_options *o)
474{
475 /*
476 * we are about to extract "ce->name"; we would not want to lose
477 * anything in the existing directory there.
478 */
479 int namelen;
480 int i;
481 struct dir_struct d;
482 char *pathbuf;
483 int cnt = 0;
484 unsigned char sha1[20];
485
486 if (S_ISGITLINK(ce->ce_mode) &&
487 resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
488 /* If we are not going to update the submodule, then
489 * we don't care.
490 */
491 if (!hashcmp(sha1, ce->sha1))
492 return 0;
493 return verify_clean_submodule(ce, action, o);
494 }
495
496 /*
497 * First let's make sure we do not have a local modification
498 * in that directory.
499 */
500 namelen = strlen(ce->name);
501 for (i = o->pos; i < o->src_index->cache_nr; i++) {
502 struct cache_entry *ce2 = o->src_index->cache[i];
503 int len = ce_namelen(ce2);
504 if (len < namelen ||
505 strncmp(ce->name, ce2->name, namelen) ||
506 ce2->name[namelen] != '/')
507 break;
508 /*
509 * ce2->name is an entry in the subdirectory.
510 */
511 if (!ce_stage(ce2)) {
512 if (verify_uptodate(ce2, o))
513 return -1;
514 add_entry(o, ce2, CE_REMOVE, 0);
515 }
516 cnt++;
517 }
518
519 /*
520 * Then we need to make sure that we do not lose a locally
521 * present file that is not ignored.
522 */
523 pathbuf = xmalloc(namelen + 2);
524 memcpy(pathbuf, ce->name, namelen);
525 strcpy(pathbuf+namelen, "/");
526
527 memset(&d, 0, sizeof(d));
528 if (o->dir)
529 d.exclude_per_dir = o->dir->exclude_per_dir;
530 i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
531 if (i)
532 return o->gently ? -1 :
533 error(ERRORMSG(o, not_uptodate_dir), ce->name);
534 free(pathbuf);
535 return cnt;
536}
537
538/*
539 * This gets called when there was no index entry for the tree entry 'dst',
540 * but we found a file in the working tree that 'lstat()' said was fine,
541 * and we're on a case-insensitive filesystem.
542 *
543 * See if we can find a case-insensitive match in the index that also
544 * matches the stat information, and assume it's that other file!
545 */
546static int icase_exists(struct unpack_trees_options *o, struct cache_entry *dst, struct stat *st)
547{
548 struct cache_entry *src;
549
550 src = index_name_exists(o->src_index, dst->name, ce_namelen(dst), 1);
551 return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID);
552}
553
554/*
555 * We do not want to remove or overwrite a working tree file that
556 * is not tracked, unless it is ignored.
557 */
558static int verify_absent(struct cache_entry *ce, const char *action,
559 struct unpack_trees_options *o)
560{
561 struct stat st;
562
563 if (o->index_only || o->reset || !o->update)
564 return 0;
565
566 if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
567 return 0;
568
569 if (!lstat(ce->name, &st)) {
570 int ret;
571 int dtype = ce_to_dtype(ce);
572 struct cache_entry *result;
573
574 /*
575 * It may be that the 'lstat()' succeeded even though
576 * target 'ce' was absent, because there is an old
577 * entry that is different only in case..
578 *
579 * Ignore that lstat() if it matches.
580 */
581 if (ignore_case && icase_exists(o, ce, &st))
582 return 0;
583
584 if (o->dir && excluded(o->dir, ce->name, &dtype))
585 /*
586 * ce->name is explicitly excluded, so it is Ok to
587 * overwrite it.
588 */
589 return 0;
590 if (S_ISDIR(st.st_mode)) {
591 /*
592 * We are checking out path "foo" and
593 * found "foo/." in the working tree.
594 * This is tricky -- if we have modified
595 * files that are in "foo/" we would lose
596 * it.
597 */
598 ret = verify_clean_subdirectory(ce, action, o);
599 if (ret < 0)
600 return ret;
601
602 /*
603 * If this removed entries from the index,
604 * what that means is:
605 *
606 * (1) the caller unpack_callback() saw path/foo
607 * in the index, and it has not removed it because
608 * it thinks it is handling 'path' as blob with
609 * D/F conflict;
610 * (2) we will return "ok, we placed a merged entry
611 * in the index" which would cause o->pos to be
612 * incremented by one;
613 * (3) however, original o->pos now has 'path/foo'
614 * marked with "to be removed".
615 *
616 * We need to increment it by the number of
617 * deleted entries here.
618 */
619 o->pos += ret;
620 return 0;
621 }
622
623 /*
624 * The previous round may already have decided to
625 * delete this path, which is in a subdirectory that
626 * is being replaced with a blob.
627 */
628 result = index_name_exists(&o->result, ce->name, ce_namelen(ce), 0);
629 if (result) {
630 if (result->ce_flags & CE_REMOVE)
631 return 0;
632 }
633
634 return o->gently ? -1 :
635 error(ERRORMSG(o, would_lose_untracked), ce->name, action);
636 }
637 return 0;
638}
639
640static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
641 struct unpack_trees_options *o)
642{
643 int update = CE_UPDATE;
644
645 if (old) {
646 /*
647 * See if we can re-use the old CE directly?
648 * That way we get the uptodate stat info.
649 *
650 * This also removes the UPDATE flag on a match; otherwise
651 * we will end up overwriting local changes in the work tree.
652 */
653 if (same(old, merge)) {
654 copy_cache_entry(merge, old);
655 update = 0;
656 } else {
657 if (verify_uptodate(old, o))
658 return -1;
659 invalidate_ce_path(old, o);
660 }
661 }
662 else {
663 if (verify_absent(merge, "overwritten", o))
664 return -1;
665 invalidate_ce_path(merge, o);
666 }
667
668 add_entry(o, merge, update, CE_STAGEMASK);
669 return 1;
670}
671
672static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
673 struct unpack_trees_options *o)
674{
675 /* Did it exist in the index? */
676 if (!old) {
677 if (verify_absent(ce, "removed", o))
678 return -1;
679 return 0;
680 }
681 if (verify_uptodate(old, o))
682 return -1;
683 add_entry(o, ce, CE_REMOVE, 0);
684 invalidate_ce_path(ce, o);
685 return 1;
686}
687
688static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
689{
690 add_entry(o, ce, 0, 0);
691 return 1;
692}
693
694#if DBRT_DEBUG
695static void show_stage_entry(FILE *o,
696 const char *label, const struct cache_entry *ce)
697{
698 if (!ce)
699 fprintf(o, "%s (missing)\n", label);
700 else
701 fprintf(o, "%s%06o %s %d\t%s\n",
702 label,
703 ce->ce_mode,
704 sha1_to_hex(ce->sha1),
705 ce_stage(ce),
706 ce->name);
707}
708#endif
709
710int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
711{
712 struct cache_entry *index;
713 struct cache_entry *head;
714 struct cache_entry *remote = stages[o->head_idx + 1];
715 int count;
716 int head_match = 0;
717 int remote_match = 0;
718
719 int df_conflict_head = 0;
720 int df_conflict_remote = 0;
721
722 int any_anc_missing = 0;
723 int no_anc_exists = 1;
724 int i;
725
726 for (i = 1; i < o->head_idx; i++) {
727 if (!stages[i] || stages[i] == o->df_conflict_entry)
728 any_anc_missing = 1;
729 else
730 no_anc_exists = 0;
731 }
732
733 index = stages[0];
734 head = stages[o->head_idx];
735
736 if (head == o->df_conflict_entry) {
737 df_conflict_head = 1;
738 head = NULL;
739 }
740
741 if (remote == o->df_conflict_entry) {
742 df_conflict_remote = 1;
743 remote = NULL;
744 }
745
746 /* First, if there's a #16 situation, note that to prevent #13
747 * and #14.
748 */
749 if (!same(remote, head)) {
750 for (i = 1; i < o->head_idx; i++) {
751 if (same(stages[i], head)) {
752 head_match = i;
753 }
754 if (same(stages[i], remote)) {
755 remote_match = i;
756 }
757 }
758 }
759
760 /* We start with cases where the index is allowed to match
761 * something other than the head: #14(ALT) and #2ALT, where it
762 * is permitted to match the result instead.
763 */
764 /* #14, #14ALT, #2ALT */
765 if (remote && !df_conflict_head && head_match && !remote_match) {
766 if (index && !same(index, remote) && !same(index, head))
767 return o->gently ? -1 : reject_merge(index, o);
768 return merged_entry(remote, index, o);
769 }
770 /*
771 * If we have an entry in the index cache, then we want to
772 * make sure that it matches head.
773 */
774 if (index && !same(index, head))
775 return o->gently ? -1 : reject_merge(index, o);
776
777 if (head) {
778 /* #5ALT, #15 */
779 if (same(head, remote))
780 return merged_entry(head, index, o);
781 /* #13, #3ALT */
782 if (!df_conflict_remote && remote_match && !head_match)
783 return merged_entry(head, index, o);
784 }
785
786 /* #1 */
787 if (!head && !remote && any_anc_missing)
788 return 0;
789
790 /* Under the new "aggressive" rule, we resolve mostly trivial
791 * cases that we historically had git-merge-one-file resolve.
792 */
793 if (o->aggressive) {
794 int head_deleted = !head && !df_conflict_head;
795 int remote_deleted = !remote && !df_conflict_remote;
796 struct cache_entry *ce = NULL;
797
798 if (index)
799 ce = index;
800 else if (head)
801 ce = head;
802 else if (remote)
803 ce = remote;
804 else {
805 for (i = 1; i < o->head_idx; i++) {
806 if (stages[i] && stages[i] != o->df_conflict_entry) {
807 ce = stages[i];
808 break;
809 }
810 }
811 }
812
813 /*
814 * Deleted in both.
815 * Deleted in one and unchanged in the other.
816 */
817 if ((head_deleted && remote_deleted) ||
818 (head_deleted && remote && remote_match) ||
819 (remote_deleted && head && head_match)) {
820 if (index)
821 return deleted_entry(index, index, o);
822 if (ce && !head_deleted) {
823 if (verify_absent(ce, "removed", o))
824 return -1;
825 }
826 return 0;
827 }
828 /*
829 * Added in both, identically.
830 */
831 if (no_anc_exists && head && remote && same(head, remote))
832 return merged_entry(head, index, o);
833
834 }
835
836 /* Below are "no merge" cases, which require that the index be
837 * up-to-date to avoid the files getting overwritten with
838 * conflict resolution files.
839 */
840 if (index) {
841 if (verify_uptodate(index, o))
842 return -1;
843 }
844
845 o->nontrivial_merge = 1;
846
847 /* #2, #3, #4, #6, #7, #9, #10, #11. */
848 count = 0;
849 if (!head_match || !remote_match) {
850 for (i = 1; i < o->head_idx; i++) {
851 if (stages[i] && stages[i] != o->df_conflict_entry) {
852 keep_entry(stages[i], o);
853 count++;
854 break;
855 }
856 }
857 }
858#if DBRT_DEBUG
859 else {
860 fprintf(stderr, "read-tree: warning #16 detected\n");
861 show_stage_entry(stderr, "head ", stages[head_match]);
862 show_stage_entry(stderr, "remote ", stages[remote_match]);
863 }
864#endif
865 if (head) { count += keep_entry(head, o); }
866 if (remote) { count += keep_entry(remote, o); }
867 return count;
868}
869
870/*
871 * Two-way merge.
872 *
873 * The rule is to "carry forward" what is in the index without losing
874 * information across a "fast forward", favoring a successful merge
875 * over a merge failure when it makes sense. For details of the
876 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
877 *
878 */
879int twoway_merge(struct cache_entry **src, struct unpack_trees_options *o)
880{
881 struct cache_entry *current = src[0];
882 struct cache_entry *oldtree = src[1];
883 struct cache_entry *newtree = src[2];
884
885 if (o->merge_size != 2)
886 return error("Cannot do a twoway merge of %d trees",
887 o->merge_size);
888
889 if (oldtree == o->df_conflict_entry)
890 oldtree = NULL;
891 if (newtree == o->df_conflict_entry)
892 newtree = NULL;
893
894 if (current) {
895 if ((!oldtree && !newtree) || /* 4 and 5 */
896 (!oldtree && newtree &&
897 same(current, newtree)) || /* 6 and 7 */
898 (oldtree && newtree &&
899 same(oldtree, newtree)) || /* 14 and 15 */
900 (oldtree && newtree &&
901 !same(oldtree, newtree) && /* 18 and 19 */
902 same(current, newtree))) {
903 return keep_entry(current, o);
904 }
905 else if (oldtree && !newtree && same(current, oldtree)) {
906 /* 10 or 11 */
907 return deleted_entry(oldtree, current, o);
908 }
909 else if (oldtree && newtree &&
910 same(current, oldtree) && !same(current, newtree)) {
911 /* 20 or 21 */
912 return merged_entry(newtree, current, o);
913 }
914 else {
915 /* all other failures */
916 if (oldtree)
917 return o->gently ? -1 : reject_merge(oldtree, o);
918 if (current)
919 return o->gently ? -1 : reject_merge(current, o);
920 if (newtree)
921 return o->gently ? -1 : reject_merge(newtree, o);
922 return -1;
923 }
924 }
925 else if (newtree) {
926 if (oldtree && !o->initial_checkout) {
927 /*
928 * deletion of the path was staged;
929 */
930 if (same(oldtree, newtree))
931 return 1;
932 return reject_merge(oldtree, o);
933 }
934 return merged_entry(newtree, current, o);
935 }
936 return deleted_entry(oldtree, current, o);
937}
938
939/*
940 * Bind merge.
941 *
942 * Keep the index entries at stage0, collapse stage1 but make sure
943 * stage0 does not have anything there.
944 */
945int bind_merge(struct cache_entry **src,
946 struct unpack_trees_options *o)
947{
948 struct cache_entry *old = src[0];
949 struct cache_entry *a = src[1];
950
951 if (o->merge_size != 1)
952 return error("Cannot do a bind merge of %d trees\n",
953 o->merge_size);
954 if (a && old)
955 return o->gently ? -1 :
956 error(ERRORMSG(o, bind_overlap), a->name, old->name);
957 if (!a)
958 return keep_entry(old, o);
959 else
960 return merged_entry(a, NULL, o);
961}
962
963/*
964 * One-way merge.
965 *
966 * The rule is:
967 * - take the stat information from stage0, take the data from stage1
968 */
969int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o)
970{
971 struct cache_entry *old = src[0];
972 struct cache_entry *a = src[1];
973
974 if (o->merge_size != 1)
975 return error("Cannot do a oneway merge of %d trees",
976 o->merge_size);
977
978 if (!a)
979 return deleted_entry(old, old, o);
980
981 if (old && same(old, a)) {
982 int update = 0;
983 if (o->reset) {
984 struct stat st;
985 if (lstat(old->name, &st) ||
986 ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID))
987 update |= CE_UPDATE;
988 }
989 add_entry(o, old, update, 0);
990 return 0;
991 }
992 return merged_entry(a, old, o);
993}