1#include "cache.h"
2#include "dir.h"
3#include "tree.h"
4#include "tree-walk.h"
5#include "cache-tree.h"
6#include "unpack-trees.h"
7#include "progress.h"
8#include "refs.h"
9#define DBRT_DEBUG 1
11struct tree_entry_list {
13 struct tree_entry_list *next;
14 unsigned int mode;
15 const char *name;
16 const unsigned char *sha1;
17};
18static struct tree_entry_list *create_tree_entry_list(struct tree *tree)
20{
21 struct tree_desc desc;
22 struct name_entry one;
23 struct tree_entry_list *ret = NULL;
24 struct tree_entry_list **list_p = &ret;
25 if (!tree->object.parsed)
27 parse_tree(tree);
28 init_tree_desc(&desc, tree->buffer, tree->size);
30 while (tree_entry(&desc, &one)) {
32 struct tree_entry_list *entry;
33 entry = xmalloc(sizeof(struct tree_entry_list));
35 entry->name = one.path;
36 entry->sha1 = one.sha1;
37 entry->mode = one.mode;
38 entry->next = NULL;
39 *list_p = entry;
41 list_p = &entry->next;
42 }
43 return ret;
44}
45static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
47{
48 int len1 = strlen(name1);
49 int len2 = strlen(name2);
50 int len = len1 < len2 ? len1 : len2;
51 int ret = memcmp(name1, name2, len);
52 unsigned char c1, c2;
53 if (ret)
54 return ret;
55 c1 = name1[len];
56 c2 = name2[len];
57 if (!c1 && dir1)
58 c1 = '/';
59 if (!c2 && dir2)
60 c2 = '/';
61 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
62 if (c1 && c2 && !ret)
63 ret = len1 - len2;
64 return ret;
65}
66static int unpack_trees_rec(struct tree_entry_list **posns, int len,
68 const char *base, struct unpack_trees_options *o,
69 struct tree_entry_list *df_conflict_list)
70{
71 int baselen = strlen(base);
72 int src_size = len + 1;
73 int i_stk = i_stk;
74 int retval = 0;
75 if (o->dir)
77 i_stk = push_exclude_per_directory(o->dir, base, strlen(base));
78 do {
80 int i;
81 const char *first;
82 int firstdir = 0;
83 int pathlen;
84 unsigned ce_size;
85 struct tree_entry_list **subposns;
86 struct cache_entry **src;
87 int any_files = 0;
88 int any_dirs = 0;
89 char *cache_name;
90 int ce_stage;
91 /* Find the first name in the input. */
93 first = NULL;
95 cache_name = NULL;
96 /* Check the cache */
98 if (o->merge && o->pos < active_nr) {
99 /* This is a bit tricky: */
100 /* If the index has a subdirectory (with
101 * contents) as the first name, it'll get a
102 * filename like "foo/bar". But that's after
103 * "foo", so the entry in trees will get
104 * handled first, at which point we'll go into
105 * "foo", and deal with "bar" from the index,
106 * because the base will be "foo/". The only
107 * way we can actually have "foo/bar" first of
108 * all the things is if the trees don't
109 * contain "foo" at all, in which case we'll
110 * handle "foo/bar" without going into the
111 * directory, but that's fine (and will return
112 * an error anyway, with the added unknown
113 * file case.
114 */
115 cache_name = active_cache[o->pos]->name;
117 if (strlen(cache_name) > baselen &&
118 !memcmp(cache_name, base, baselen)) {
119 cache_name += baselen;
120 first = cache_name;
121 } else {
122 cache_name = NULL;
123 }
124 }
125#if DBRT_DEBUG > 1
127 if (first)
128 printf("index %s\n", first);
129#endif
130 for (i = 0; i < len; i++) {
131 if (!posns[i] || posns[i] == df_conflict_list)
132 continue;
133#if DBRT_DEBUG > 1
134 printf("%d %s\n", i + 1, posns[i]->name);
135#endif
136 if (!first || entcmp(first, firstdir,
137 posns[i]->name,
138 S_ISDIR(posns[i]->mode)) > 0) {
139 first = posns[i]->name;
140 firstdir = S_ISDIR(posns[i]->mode);
141 }
142 }
143 /* No name means we're done */
144 if (!first)
145 goto leave_directory;
146 pathlen = strlen(first);
148 ce_size = cache_entry_size(baselen + pathlen);
149 src = xcalloc(src_size, sizeof(struct cache_entry *));
151 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
153 if (cache_name && !strcmp(cache_name, first)) {
155 any_files = 1;
156 src[0] = active_cache[o->pos];
157 remove_cache_entry_at(o->pos);
158 }
159 for (i = 0; i < len; i++) {
161 struct cache_entry *ce;
162 if (!posns[i] ||
164 (posns[i] != df_conflict_list &&
165 strcmp(first, posns[i]->name))) {
166 continue;
167 }
168 if (posns[i] == df_conflict_list) {
170 src[i + o->merge] = o->df_conflict_entry;
171 continue;
172 }
173 if (S_ISDIR(posns[i]->mode)) {
175 struct tree *tree = lookup_tree(posns[i]->sha1);
176 any_dirs = 1;
177 parse_tree(tree);
178 subposns[i] = create_tree_entry_list(tree);
179 posns[i] = posns[i]->next;
180 src[i + o->merge] = o->df_conflict_entry;
181 continue;
182 }
183 if (!o->merge)
185 ce_stage = 0;
186 else if (i + 1 < o->head_idx)
187 ce_stage = 1;
188 else if (i + 1 > o->head_idx)
189 ce_stage = 3;
190 else
191 ce_stage = 2;
192 ce = xcalloc(1, ce_size);
194 ce->ce_mode = create_ce_mode(posns[i]->mode);
195 ce->ce_flags = create_ce_flags(baselen + pathlen,
196 ce_stage);
197 memcpy(ce->name, base, baselen);
198 memcpy(ce->name + baselen, first, pathlen + 1);
199 any_files = 1;
201 hashcpy(ce->sha1, posns[i]->sha1);
203 src[i + o->merge] = ce;
204 subposns[i] = df_conflict_list;
205 posns[i] = posns[i]->next;
206 }
207 if (any_files) {
208 if (o->merge) {
209 int ret;
210#if DBRT_DEBUG > 1
212 printf("%s:\n", first);
213 for (i = 0; i < src_size; i++) {
214 printf(" %d ", i);
215 if (src[i])
216 printf("%s\n", sha1_to_hex(src[i]->sha1));
217 else
218 printf("\n");
219 }
220#endif
221 ret = o->fn(src, o);
222#if DBRT_DEBUG > 1
224 printf("Added %d entries\n", ret);
225#endif
226 o->pos += ret;
227 } else {
228 for (i = 0; i < src_size; i++) {
229 if (src[i]) {
230 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
231 }
232 }
233 }
234 }
235 if (any_dirs) {
236 char *newbase = xmalloc(baselen + 2 + pathlen);
237 memcpy(newbase, base, baselen);
238 memcpy(newbase + baselen, first, pathlen);
239 newbase[baselen + pathlen] = '/';
240 newbase[baselen + pathlen + 1] = '\0';
241 if (unpack_trees_rec(subposns, len, newbase, o,
242 df_conflict_list)) {
243 retval = -1;
244 goto leave_directory;
245 }
246 free(newbase);
247 }
248 free(subposns);
249 free(src);
250 } while (1);
251 leave_directory:
253 if (o->dir)
254 pop_exclude_per_directory(o->dir, i_stk);
255 return retval;
256}
257/* Unlink the last component and attempt to remove leading
259 * directories, in case this unlink is the removal of the
260 * last entry in the directory -- empty directories are removed.
261 */
262static void unlink_entry(char *name, char *last_symlink)
263{
264 char *cp, *prev;
265 if (has_symlink_leading_path(name, last_symlink))
267 return;
268 if (unlink(name))
269 return;
270 prev = NULL;
271 while (1) {
272 int status;
273 cp = strrchr(name, '/');
274 if (prev)
275 *prev = '/';
276 if (!cp)
277 break;
278 *cp = 0;
280 status = rmdir(name);
281 if (status) {
282 *cp = '/';
283 break;
284 }
285 prev = cp;
286 }
287}
288static struct checkout state;
290static void check_updates(struct cache_entry **src, int nr,
291 struct unpack_trees_options *o)
292{
293 unsigned short mask = htons(CE_UPDATE);
294 unsigned cnt = 0, total = 0;
295 struct progress progress;
296 char last_symlink[PATH_MAX];
297 if (o->update && o->verbose_update) {
299 for (total = cnt = 0; cnt < nr; cnt++) {
300 struct cache_entry *ce = src[cnt];
301 if (!ce->ce_mode || ce->ce_flags & mask)
302 total++;
303 }
304 start_progress_delay(&progress, "Checking %u files out...",
306 "", total, 50, 2);
307 cnt = 0;
308 }
309 *last_symlink = '\0';
311 while (nr--) {
312 struct cache_entry *ce = *src++;
313 if (total)
315 if (!ce->ce_mode || ce->ce_flags & mask)
316 display_progress(&progress, ++cnt);
317 if (!ce->ce_mode) {
318 if (o->update)
319 unlink_entry(ce->name, last_symlink);
320 continue;
321 }
322 if (ce->ce_flags & mask) {
323 ce->ce_flags &= ~mask;
324 if (o->update) {
325 checkout_entry(ce, &state, NULL);
326 *last_symlink = '\0';
327 }
328 }
329 }
330 if (total)
331 stop_progress(&progress);;
332}
333int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
335{
336 unsigned len = object_list_length(trees);
337 struct tree_entry_list **posns;
338 int i;
339 struct object_list *posn = trees;
340 struct tree_entry_list df_conflict_list;
341 static struct cache_entry *dfc;
342 memset(&df_conflict_list, 0, sizeof(df_conflict_list));
344 df_conflict_list.next = &df_conflict_list;
345 memset(&state, 0, sizeof(state));
346 state.base_dir = "";
347 state.force = 1;
348 state.quiet = 1;
349 state.refresh_cache = 1;
350 o->merge_size = len;
352 if (!dfc)
354 dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
355 o->df_conflict_entry = dfc;
356 if (len) {
358 posns = xmalloc(len * sizeof(struct tree_entry_list *));
359 for (i = 0; i < len; i++) {
360 posns[i] = create_tree_entry_list((struct tree *) posn->item);
361 posn = posn->next;
362 }
363 if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
364 o, &df_conflict_list))
365 return -1;
366 }
367 if (o->trivial_merges_only && o->nontrivial_merge)
369 die("Merge requires file-level merging");
370 check_updates(active_cache, active_nr, o);
372 return 0;
373}
374/* Here come the merge functions */
376static void reject_merge(struct cache_entry *ce)
378{
379 die("Entry '%s' would be overwritten by merge. Cannot merge.",
380 ce->name);
381}
382static int same(struct cache_entry *a, struct cache_entry *b)
384{
385 if (!!a != !!b)
386 return 0;
387 if (!a && !b)
388 return 1;
389 return a->ce_mode == b->ce_mode &&
390 !hashcmp(a->sha1, b->sha1);
391}
392/*
395 * When a CE gets turned into an unmerged entry, we
396 * want it to be up-to-date
397 */
398static void verify_uptodate(struct cache_entry *ce,
399 struct unpack_trees_options *o)
400{
401 struct stat st;
402 if (o->index_only || o->reset)
404 return;
405 if (!lstat(ce->name, &st)) {
407 unsigned changed = ce_match_stat(ce, &st, 1);
408 if (!changed)
409 return;
410 /*
411 * NEEDSWORK: the current default policy is to allow
412 * submodule to be out of sync wrt the supermodule
413 * index. This needs to be tightened later for
414 * submodules that are marked to be automatically
415 * checked out.
416 */
417 if (S_ISGITLINK(ntohl(ce->ce_mode)))
418 return;
419 errno = 0;
420 }
421 if (errno == ENOENT)
422 return;
423 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
424}
425static void invalidate_ce_path(struct cache_entry *ce)
427{
428 if (ce)
429 cache_tree_invalidate_path(active_cache_tree, ce->name);
430}
431/*
433 * Check that checking out ce->sha1 in subdir ce->name is not
434 * going to overwrite any working files.
435 *
436 * Currently, git does not checkout subprojects during a superproject
437 * checkout, so it is not going to overwrite anything.
438 */
439static int verify_clean_submodule(struct cache_entry *ce, const char *action,
440 struct unpack_trees_options *o)
441{
442 return 0;
443}
444static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
446 struct unpack_trees_options *o)
447{
448 /*
449 * we are about to extract "ce->name"; we would not want to lose
450 * anything in the existing directory there.
451 */
452 int namelen;
453 int pos, i;
454 struct dir_struct d;
455 char *pathbuf;
456 int cnt = 0;
457 unsigned char sha1[20];
458 if (S_ISGITLINK(ntohl(ce->ce_mode)) &&
460 resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
461 /* If we are not going to update the submodule, then
462 * we don't care.
463 */
464 if (!hashcmp(sha1, ce->sha1))
465 return 0;
466 return verify_clean_submodule(ce, action, o);
467 }
468 /*
470 * First let's make sure we do not have a local modification
471 * in that directory.
472 */
473 namelen = strlen(ce->name);
474 pos = cache_name_pos(ce->name, namelen);
475 if (0 <= pos)
476 return cnt; /* we have it as nondirectory */
477 pos = -pos - 1;
478 for (i = pos; i < active_nr; i++) {
479 struct cache_entry *ce = active_cache[i];
480 int len = ce_namelen(ce);
481 if (len < namelen ||
482 strncmp(ce->name, ce->name, namelen) ||
483 ce->name[namelen] != '/')
484 break;
485 /*
486 * ce->name is an entry in the subdirectory.
487 */
488 if (!ce_stage(ce)) {
489 verify_uptodate(ce, o);
490 ce->ce_mode = 0;
491 }
492 cnt++;
493 }
494 /*
496 * Then we need to make sure that we do not lose a locally
497 * present file that is not ignored.
498 */
499 pathbuf = xmalloc(namelen + 2);
500 memcpy(pathbuf, ce->name, namelen);
501 strcpy(pathbuf+namelen, "/");
502 memset(&d, 0, sizeof(d));
504 if (o->dir)
505 d.exclude_per_dir = o->dir->exclude_per_dir;
506 i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
507 if (i)
508 die("Updating '%s' would lose untracked files in it",
509 ce->name);
510 free(pathbuf);
511 return cnt;
512}
513/*
515 * We do not want to remove or overwrite a working tree file that
516 * is not tracked, unless it is ignored.
517 */
518static void verify_absent(struct cache_entry *ce, const char *action,
519 struct unpack_trees_options *o)
520{
521 struct stat st;
522 if (o->index_only || o->reset || !o->update)
524 return;
525 if (has_symlink_leading_path(ce->name, NULL))
527 return;
528 if (!lstat(ce->name, &st)) {
530 int cnt;
531 if (o->dir && excluded(o->dir, ce->name))
533 /*
534 * ce->name is explicitly excluded, so it is Ok to
535 * overwrite it.
536 */
537 return;
538 if (S_ISDIR(st.st_mode)) {
539 /*
540 * We are checking out path "foo" and
541 * found "foo/." in the working tree.
542 * This is tricky -- if we have modified
543 * files that are in "foo/" we would lose
544 * it.
545 */
546 cnt = verify_clean_subdirectory(ce, action, o);
547 /*
549 * If this removed entries from the index,
550 * what that means is:
551 *
552 * (1) the caller unpack_trees_rec() saw path/foo
553 * in the index, and it has not removed it because
554 * it thinks it is handling 'path' as blob with
555 * D/F conflict;
556 * (2) we will return "ok, we placed a merged entry
557 * in the index" which would cause o->pos to be
558 * incremented by one;
559 * (3) however, original o->pos now has 'path/foo'
560 * marked with "to be removed".
561 *
562 * We need to increment it by the number of
563 * deleted entries here.
564 */
565 o->pos += cnt;
566 return;
567 }
568 /*
570 * The previous round may already have decided to
571 * delete this path, which is in a subdirectory that
572 * is being replaced with a blob.
573 */
574 cnt = cache_name_pos(ce->name, strlen(ce->name));
575 if (0 <= cnt) {
576 struct cache_entry *ce = active_cache[cnt];
577 if (!ce_stage(ce) && !ce->ce_mode)
578 return;
579 }
580 die("Untracked working tree file '%s' "
582 "would be %s by merge.", ce->name, action);
583 }
584}
585static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
587 struct unpack_trees_options *o)
588{
589 merge->ce_flags |= htons(CE_UPDATE);
590 if (old) {
591 /*
592 * See if we can re-use the old CE directly?
593 * That way we get the uptodate stat info.
594 *
595 * This also removes the UPDATE flag on
596 * a match.
597 */
598 if (same(old, merge)) {
599 *merge = *old;
600 } else {
601 verify_uptodate(old, o);
602 invalidate_ce_path(old);
603 }
604 }
605 else {
606 verify_absent(merge, "overwritten", o);
607 invalidate_ce_path(merge);
608 }
609 merge->ce_flags &= ~htons(CE_STAGEMASK);
611 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
612 return 1;
613}
614static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
616 struct unpack_trees_options *o)
617{
618 if (old)
619 verify_uptodate(old, o);
620 else
621 verify_absent(ce, "removed", o);
622 ce->ce_mode = 0;
623 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
624 invalidate_ce_path(ce);
625 return 1;
626}
627static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
629{
630 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
631 return 1;
632}
633#if DBRT_DEBUG
635static void show_stage_entry(FILE *o,
636 const char *label, const struct cache_entry *ce)
637{
638 if (!ce)
639 fprintf(o, "%s (missing)\n", label);
640 else
641 fprintf(o, "%s%06o %s %d\t%s\n",
642 label,
643 ntohl(ce->ce_mode),
644 sha1_to_hex(ce->sha1),
645 ce_stage(ce),
646 ce->name);
647}
648#endif
649int threeway_merge(struct cache_entry **stages,
651 struct unpack_trees_options *o)
652{
653 struct cache_entry *index;
654 struct cache_entry *head;
655 struct cache_entry *remote = stages[o->head_idx + 1];
656 int count;
657 int head_match = 0;
658 int remote_match = 0;
659 int df_conflict_head = 0;
661 int df_conflict_remote = 0;
662 int any_anc_missing = 0;
664 int no_anc_exists = 1;
665 int i;
666 for (i = 1; i < o->head_idx; i++) {
668 if (!stages[i] || stages[i] == o->df_conflict_entry)
669 any_anc_missing = 1;
670 else
671 no_anc_exists = 0;
672 }
673 index = stages[0];
675 head = stages[o->head_idx];
676 if (head == o->df_conflict_entry) {
678 df_conflict_head = 1;
679 head = NULL;
680 }
681 if (remote == o->df_conflict_entry) {
683 df_conflict_remote = 1;
684 remote = NULL;
685 }
686 /* First, if there's a #16 situation, note that to prevent #13
688 * and #14.
689 */
690 if (!same(remote, head)) {
691 for (i = 1; i < o->head_idx; i++) {
692 if (same(stages[i], head)) {
693 head_match = i;
694 }
695 if (same(stages[i], remote)) {
696 remote_match = i;
697 }
698 }
699 }
700 /* We start with cases where the index is allowed to match
702 * something other than the head: #14(ALT) and #2ALT, where it
703 * is permitted to match the result instead.
704 */
705 /* #14, #14ALT, #2ALT */
706 if (remote && !df_conflict_head && head_match && !remote_match) {
707 if (index && !same(index, remote) && !same(index, head))
708 reject_merge(index);
709 return merged_entry(remote, index, o);
710 }
711 /*
712 * If we have an entry in the index cache, then we want to
713 * make sure that it matches head.
714 */
715 if (index && !same(index, head)) {
716 reject_merge(index);
717 }
718 if (head) {
720 /* #5ALT, #15 */
721 if (same(head, remote))
722 return merged_entry(head, index, o);
723 /* #13, #3ALT */
724 if (!df_conflict_remote && remote_match && !head_match)
725 return merged_entry(head, index, o);
726 }
727 /* #1 */
729 if (!head && !remote && any_anc_missing)
730 return 0;
731 /* Under the new "aggressive" rule, we resolve mostly trivial
733 * cases that we historically had git-merge-one-file resolve.
734 */
735 if (o->aggressive) {
736 int head_deleted = !head && !df_conflict_head;
737 int remote_deleted = !remote && !df_conflict_remote;
738 struct cache_entry *ce = NULL;
739 if (index)
741 ce = index;
742 else if (head)
743 ce = head;
744 else if (remote)
745 ce = remote;
746 else {
747 for (i = 1; i < o->head_idx; i++) {
748 if (stages[i] && stages[i] != o->df_conflict_entry) {
749 ce = stages[i];
750 break;
751 }
752 }
753 }
754 /*
756 * Deleted in both.
757 * Deleted in one and unchanged in the other.
758 */
759 if ((head_deleted && remote_deleted) ||
760 (head_deleted && remote && remote_match) ||
761 (remote_deleted && head && head_match)) {
762 if (index)
763 return deleted_entry(index, index, o);
764 else if (ce && !head_deleted)
765 verify_absent(ce, "removed", o);
766 return 0;
767 }
768 /*
769 * Added in both, identically.
770 */
771 if (no_anc_exists && head && remote && same(head, remote))
772 return merged_entry(head, index, o);
773 }
775 /* Below are "no merge" cases, which require that the index be
777 * up-to-date to avoid the files getting overwritten with
778 * conflict resolution files.
779 */
780 if (index) {
781 verify_uptodate(index, o);
782 }
783 o->nontrivial_merge = 1;
785 /* #2, #3, #4, #6, #7, #9, #10, #11. */
787 count = 0;
788 if (!head_match || !remote_match) {
789 for (i = 1; i < o->head_idx; i++) {
790 if (stages[i] && stages[i] != o->df_conflict_entry) {
791 keep_entry(stages[i], o);
792 count++;
793 break;
794 }
795 }
796 }
797#if DBRT_DEBUG
798 else {
799 fprintf(stderr, "read-tree: warning #16 detected\n");
800 show_stage_entry(stderr, "head ", stages[head_match]);
801 show_stage_entry(stderr, "remote ", stages[remote_match]);
802 }
803#endif
804 if (head) { count += keep_entry(head, o); }
805 if (remote) { count += keep_entry(remote, o); }
806 return count;
807}
808/*
810 * Two-way merge.
811 *
812 * The rule is to "carry forward" what is in the index without losing
813 * information across a "fast forward", favoring a successful merge
814 * over a merge failure when it makes sense. For details of the
815 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
816 *
817 */
818int twoway_merge(struct cache_entry **src,
819 struct unpack_trees_options *o)
820{
821 struct cache_entry *current = src[0];
822 struct cache_entry *oldtree = src[1];
823 struct cache_entry *newtree = src[2];
824 if (o->merge_size != 2)
826 return error("Cannot do a twoway merge of %d trees",
827 o->merge_size);
828 if (oldtree == o->df_conflict_entry)
830 oldtree = NULL;
831 if (newtree == o->df_conflict_entry)
832 newtree = NULL;
833 if (current) {
835 if ((!oldtree && !newtree) || /* 4 and 5 */
836 (!oldtree && newtree &&
837 same(current, newtree)) || /* 6 and 7 */
838 (oldtree && newtree &&
839 same(oldtree, newtree)) || /* 14 and 15 */
840 (oldtree && newtree &&
841 !same(oldtree, newtree) && /* 18 and 19 */
842 same(current, newtree))) {
843 return keep_entry(current, o);
844 }
845 else if (oldtree && !newtree && same(current, oldtree)) {
846 /* 10 or 11 */
847 return deleted_entry(oldtree, current, o);
848 }
849 else if (oldtree && newtree &&
850 same(current, oldtree) && !same(current, newtree)) {
851 /* 20 or 21 */
852 return merged_entry(newtree, current, o);
853 }
854 else {
855 /* all other failures */
856 if (oldtree)
857 reject_merge(oldtree);
858 if (current)
859 reject_merge(current);
860 if (newtree)
861 reject_merge(newtree);
862 return -1;
863 }
864 }
865 else if (newtree)
866 return merged_entry(newtree, current, o);
867 else
868 return deleted_entry(oldtree, current, o);
869}
870/*
872 * Bind merge.
873 *
874 * Keep the index entries at stage0, collapse stage1 but make sure
875 * stage0 does not have anything there.
876 */
877int bind_merge(struct cache_entry **src,
878 struct unpack_trees_options *o)
879{
880 struct cache_entry *old = src[0];
881 struct cache_entry *a = src[1];
882 if (o->merge_size != 1)
884 return error("Cannot do a bind merge of %d trees\n",
885 o->merge_size);
886 if (a && old)
887 die("Entry '%s' overlaps. Cannot bind.", a->name);
888 if (!a)
889 return keep_entry(old, o);
890 else
891 return merged_entry(a, NULL, o);
892}
893/*
895 * One-way merge.
896 *
897 * The rule is:
898 * - take the stat information from stage0, take the data from stage1
899 */
900int oneway_merge(struct cache_entry **src,
901 struct unpack_trees_options *o)
902{
903 struct cache_entry *old = src[0];
904 struct cache_entry *a = src[1];
905 if (o->merge_size != 1)
907 return error("Cannot do a oneway merge of %d trees",
908 o->merge_size);
909 if (!a)
911 return deleted_entry(old, old, o);
912 if (old && same(old, a)) {
913 if (o->reset) {
914 struct stat st;
915 if (lstat(old->name, &st) ||
916 ce_match_stat(old, &st, 1))
917 old->ce_flags |= htons(CE_UPDATE);
918 }
919 return keep_entry(old, o);
920 }
921 return merged_entry(a, old, o);
922}