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_desc *desc)
20{
21 struct name_entry one;
22 struct tree_entry_list *ret = NULL;
23 struct tree_entry_list **list_p = &ret;
24 while (tree_entry(desc, &one)) {
26 struct tree_entry_list *entry;
27 entry = xmalloc(sizeof(struct tree_entry_list));
29 entry->name = one.path;
30 entry->sha1 = one.sha1;
31 entry->mode = one.mode;
32 entry->next = NULL;
33 *list_p = entry;
35 list_p = &entry->next;
36 }
37 return ret;
38}
39static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
41{
42 int len1 = strlen(name1);
43 int len2 = strlen(name2);
44 int len = len1 < len2 ? len1 : len2;
45 int ret = memcmp(name1, name2, len);
46 unsigned char c1, c2;
47 if (ret)
48 return ret;
49 c1 = name1[len];
50 c2 = name2[len];
51 if (!c1 && dir1)
52 c1 = '/';
53 if (!c2 && dir2)
54 c2 = '/';
55 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
56 if (c1 && c2 && !ret)
57 ret = len1 - len2;
58 return ret;
59}
60static inline void remove_entry(int remove)
62{
63 if (remove >= 0)
64 remove_cache_entry_at(remove);
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 remove;
72 int baselen = strlen(base);
73 int src_size = len + 1;
74 int retval = 0;
75 do {
77 int i;
78 const char *first;
79 int firstdir = 0;
80 int pathlen;
81 unsigned ce_size;
82 struct tree_entry_list **subposns;
83 struct cache_entry **src;
84 int any_files = 0;
85 int any_dirs = 0;
86 char *cache_name;
87 int ce_stage;
88 /* Find the first name in the input. */
90 first = NULL;
92 cache_name = NULL;
93 /* Check the cache */
95 if (o->merge && o->pos < active_nr) {
96 /* This is a bit tricky: */
97 /* If the index has a subdirectory (with
98 * contents) as the first name, it'll get a
99 * filename like "foo/bar". But that's after
100 * "foo", so the entry in trees will get
101 * handled first, at which point we'll go into
102 * "foo", and deal with "bar" from the index,
103 * because the base will be "foo/". The only
104 * way we can actually have "foo/bar" first of
105 * all the things is if the trees don't
106 * contain "foo" at all, in which case we'll
107 * handle "foo/bar" without going into the
108 * directory, but that's fine (and will return
109 * an error anyway, with the added unknown
110 * file case.
111 */
112 cache_name = active_cache[o->pos]->name;
114 if (strlen(cache_name) > baselen &&
115 !memcmp(cache_name, base, baselen)) {
116 cache_name += baselen;
117 first = cache_name;
118 } else {
119 cache_name = NULL;
120 }
121 }
122#if DBRT_DEBUG > 1
124 if (first)
125 printf("index %s\n", first);
126#endif
127 for (i = 0; i < len; i++) {
128 if (!posns[i] || posns[i] == df_conflict_list)
129 continue;
130#if DBRT_DEBUG > 1
131 printf("%d %s\n", i + 1, posns[i]->name);
132#endif
133 if (!first || entcmp(first, firstdir,
134 posns[i]->name,
135 S_ISDIR(posns[i]->mode)) > 0) {
136 first = posns[i]->name;
137 firstdir = S_ISDIR(posns[i]->mode);
138 }
139 }
140 /* No name means we're done */
141 if (!first)
142 goto leave_directory;
143 pathlen = strlen(first);
145 ce_size = cache_entry_size(baselen + pathlen);
146 src = xcalloc(src_size, sizeof(struct cache_entry *));
148 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
150 remove = -1;
152 if (cache_name && !strcmp(cache_name, first)) {
153 any_files = 1;
154 src[0] = active_cache[o->pos];
155 remove = o->pos;
156 }
157 for (i = 0; i < len; i++) {
159 struct cache_entry *ce;
160 if (!posns[i] ||
162 (posns[i] != df_conflict_list &&
163 strcmp(first, posns[i]->name))) {
164 continue;
165 }
166 if (posns[i] == df_conflict_list) {
168 src[i + o->merge] = o->df_conflict_entry;
169 continue;
170 }
171 if (S_ISDIR(posns[i]->mode)) {
173 struct tree *tree = lookup_tree(posns[i]->sha1);
174 struct tree_desc t;
175 any_dirs = 1;
176 parse_tree(tree);
177 init_tree_desc(&t, tree->buffer, tree->size);
178 subposns[i] = create_tree_entry_list(&t);
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, remove);
222#if DBRT_DEBUG > 1
224 printf("Added %d entries\n", ret);
225#endif
226 o->pos += ret;
227 } else {
228 remove_entry(remove);
229 for (i = 0; i < src_size; i++) {
230 if (src[i]) {
231 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
232 }
233 }
234 }
235 }
236 if (any_dirs) {
237 char *newbase = xmalloc(baselen + 2 + pathlen);
238 memcpy(newbase, base, baselen);
239 memcpy(newbase + baselen, first, pathlen);
240 newbase[baselen + pathlen] = '/';
241 newbase[baselen + pathlen + 1] = '\0';
242 if (unpack_trees_rec(subposns, len, newbase, o,
243 df_conflict_list)) {
244 retval = -1;
245 goto leave_directory;
246 }
247 free(newbase);
248 }
249 free(subposns);
250 free(src);
251 } while (1);
252 leave_directory:
254 return retval;
255}
256/* Unlink the last component and attempt to remove leading
258 * directories, in case this unlink is the removal of the
259 * last entry in the directory -- empty directories are removed.
260 */
261static void unlink_entry(char *name, char *last_symlink)
262{
263 char *cp, *prev;
264 if (has_symlink_leading_path(name, last_symlink))
266 return;
267 if (unlink(name))
268 return;
269 prev = NULL;
270 while (1) {
271 int status;
272 cp = strrchr(name, '/');
273 if (prev)
274 *prev = '/';
275 if (!cp)
276 break;
277 *cp = 0;
279 status = rmdir(name);
280 if (status) {
281 *cp = '/';
282 break;
283 }
284 prev = cp;
285 }
286}
287static struct checkout state;
289static void check_updates(struct cache_entry **src, int nr,
290 struct unpack_trees_options *o)
291{
292 unsigned cnt = 0, total = 0;
293 struct progress *progress = NULL;
294 char last_symlink[PATH_MAX];
295 if (o->update && o->verbose_update) {
297 for (total = cnt = 0; cnt < nr; cnt++) {
298 struct cache_entry *ce = src[cnt];
299 if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
300 total++;
301 }
302 progress = start_progress_delay("Checking out files",
304 total, 50, 2);
305 cnt = 0;
306 }
307 *last_symlink = '\0';
309 while (nr--) {
310 struct cache_entry *ce = *src++;
311 if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
313 display_progress(progress, ++cnt);
314 if (ce->ce_flags & CE_REMOVE) {
315 if (o->update)
316 unlink_entry(ce->name, last_symlink);
317 continue;
318 }
319 if (ce->ce_flags & CE_UPDATE) {
320 ce->ce_flags &= ~CE_UPDATE;
321 if (o->update) {
322 checkout_entry(ce, &state, NULL);
323 *last_symlink = '\0';
324 }
325 }
326 }
327 stop_progress(&progress);
328}
329int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
331{
332 struct tree_entry_list **posns;
333 int i;
334 struct tree_entry_list df_conflict_list;
335 static struct cache_entry *dfc;
336 memset(&df_conflict_list, 0, sizeof(df_conflict_list));
338 df_conflict_list.next = &df_conflict_list;
339 memset(&state, 0, sizeof(state));
340 state.base_dir = "";
341 state.force = 1;
342 state.quiet = 1;
343 state.refresh_cache = 1;
344 o->merge_size = len;
346 if (!dfc)
348 dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
349 o->df_conflict_entry = dfc;
350 if (len) {
352 posns = xmalloc(len * sizeof(struct tree_entry_list *));
353 for (i = 0; i < len; i++)
354 posns[i] = create_tree_entry_list(t+i);
355 if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
357 o, &df_conflict_list))
358 return -1;
359 }
360 if (o->trivial_merges_only && o->nontrivial_merge)
362 die("Merge requires file-level merging");
363 check_updates(active_cache, active_nr, o);
365 return 0;
366}
367/* Here come the merge functions */
369static void reject_merge(struct cache_entry *ce)
371{
372 die("Entry '%s' would be overwritten by merge. Cannot merge.",
373 ce->name);
374}
375static int same(struct cache_entry *a, struct cache_entry *b)
377{
378 if (!!a != !!b)
379 return 0;
380 if (!a && !b)
381 return 1;
382 return a->ce_mode == b->ce_mode &&
383 !hashcmp(a->sha1, b->sha1);
384}
385/*
388 * When a CE gets turned into an unmerged entry, we
389 * want it to be up-to-date
390 */
391static void verify_uptodate(struct cache_entry *ce,
392 struct unpack_trees_options *o)
393{
394 struct stat st;
395 if (o->index_only || o->reset)
397 return;
398 if (!lstat(ce->name, &st)) {
400 unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID);
401 if (!changed)
402 return;
403 /*
404 * NEEDSWORK: the current default policy is to allow
405 * submodule to be out of sync wrt the supermodule
406 * index. This needs to be tightened later for
407 * submodules that are marked to be automatically
408 * checked out.
409 */
410 if (S_ISGITLINK(ce->ce_mode))
411 return;
412 errno = 0;
413 }
414 if (errno == ENOENT)
415 return;
416 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
417}
418static void invalidate_ce_path(struct cache_entry *ce)
420{
421 if (ce)
422 cache_tree_invalidate_path(active_cache_tree, ce->name);
423}
424/*
426 * Check that checking out ce->sha1 in subdir ce->name is not
427 * going to overwrite any working files.
428 *
429 * Currently, git does not checkout subprojects during a superproject
430 * checkout, so it is not going to overwrite anything.
431 */
432static int verify_clean_submodule(struct cache_entry *ce, const char *action,
433 struct unpack_trees_options *o)
434{
435 return 0;
436}
437static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
439 struct unpack_trees_options *o)
440{
441 /*
442 * we are about to extract "ce->name"; we would not want to lose
443 * anything in the existing directory there.
444 */
445 int namelen;
446 int pos, i;
447 struct dir_struct d;
448 char *pathbuf;
449 int cnt = 0;
450 unsigned char sha1[20];
451 if (S_ISGITLINK(ce->ce_mode) &&
453 resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
454 /* If we are not going to update the submodule, then
455 * we don't care.
456 */
457 if (!hashcmp(sha1, ce->sha1))
458 return 0;
459 return verify_clean_submodule(ce, action, o);
460 }
461 /*
463 * First let's make sure we do not have a local modification
464 * in that directory.
465 */
466 namelen = strlen(ce->name);
467 pos = cache_name_pos(ce->name, namelen);
468 if (0 <= pos)
469 return cnt; /* we have it as nondirectory */
470 pos = -pos - 1;
471 for (i = pos; i < active_nr; i++) {
472 struct cache_entry *ce = active_cache[i];
473 int len = ce_namelen(ce);
474 if (len < namelen ||
475 strncmp(ce->name, ce->name, namelen) ||
476 ce->name[namelen] != '/')
477 break;
478 /*
479 * ce->name is an entry in the subdirectory.
480 */
481 if (!ce_stage(ce)) {
482 verify_uptodate(ce, o);
483 ce->ce_flags |= CE_REMOVE;
484 }
485 cnt++;
486 }
487 /*
489 * Then we need to make sure that we do not lose a locally
490 * present file that is not ignored.
491 */
492 pathbuf = xmalloc(namelen + 2);
493 memcpy(pathbuf, ce->name, namelen);
494 strcpy(pathbuf+namelen, "/");
495 memset(&d, 0, sizeof(d));
497 if (o->dir)
498 d.exclude_per_dir = o->dir->exclude_per_dir;
499 i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
500 if (i)
501 die("Updating '%s' would lose untracked files in it",
502 ce->name);
503 free(pathbuf);
504 return cnt;
505}
506/*
508 * We do not want to remove or overwrite a working tree file that
509 * is not tracked, unless it is ignored.
510 */
511static void verify_absent(struct cache_entry *ce, const char *action,
512 struct unpack_trees_options *o)
513{
514 struct stat st;
515 if (o->index_only || o->reset || !o->update)
517 return;
518 if (has_symlink_leading_path(ce->name, NULL))
520 return;
521 if (!lstat(ce->name, &st)) {
523 int cnt;
524 int dtype = ce_to_dtype(ce);
525 if (o->dir && excluded(o->dir, ce->name, &dtype))
527 /*
528 * ce->name is explicitly excluded, so it is Ok to
529 * overwrite it.
530 */
531 return;
532 if (S_ISDIR(st.st_mode)) {
533 /*
534 * We are checking out path "foo" and
535 * found "foo/." in the working tree.
536 * This is tricky -- if we have modified
537 * files that are in "foo/" we would lose
538 * it.
539 */
540 cnt = verify_clean_subdirectory(ce, action, o);
541 /*
543 * If this removed entries from the index,
544 * what that means is:
545 *
546 * (1) the caller unpack_trees_rec() saw path/foo
547 * in the index, and it has not removed it because
548 * it thinks it is handling 'path' as blob with
549 * D/F conflict;
550 * (2) we will return "ok, we placed a merged entry
551 * in the index" which would cause o->pos to be
552 * incremented by one;
553 * (3) however, original o->pos now has 'path/foo'
554 * marked with "to be removed".
555 *
556 * We need to increment it by the number of
557 * deleted entries here.
558 */
559 o->pos += cnt;
560 return;
561 }
562 /*
564 * The previous round may already have decided to
565 * delete this path, which is in a subdirectory that
566 * is being replaced with a blob.
567 */
568 cnt = cache_name_pos(ce->name, strlen(ce->name));
569 if (0 <= cnt) {
570 struct cache_entry *ce = active_cache[cnt];
571 if (ce->ce_flags & CE_REMOVE)
572 return;
573 }
574 die("Untracked working tree file '%s' "
576 "would be %s by merge.", ce->name, action);
577 }
578}
579static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
581 struct unpack_trees_options *o)
582{
583 merge->ce_flags |= CE_UPDATE;
584 if (old) {
585 /*
586 * See if we can re-use the old CE directly?
587 * That way we get the uptodate stat info.
588 *
589 * This also removes the UPDATE flag on
590 * a match.
591 */
592 if (same(old, merge)) {
593 memcpy(merge, old, offsetof(struct cache_entry, name));
594 } else {
595 verify_uptodate(old, o);
596 invalidate_ce_path(old);
597 }
598 }
599 else {
600 verify_absent(merge, "overwritten", o);
601 invalidate_ce_path(merge);
602 }
603 merge->ce_flags &= ~CE_STAGEMASK;
605 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
606 return 1;
607}
608static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
610 struct unpack_trees_options *o)
611{
612 if (old)
613 verify_uptodate(old, o);
614 else
615 verify_absent(ce, "removed", o);
616 ce->ce_flags |= CE_REMOVE;
617 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
618 invalidate_ce_path(ce);
619 return 1;
620}
621static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
623{
624 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
625 return 1;
626}
627#if DBRT_DEBUG
629static void show_stage_entry(FILE *o,
630 const char *label, const struct cache_entry *ce)
631{
632 if (!ce)
633 fprintf(o, "%s (missing)\n", label);
634 else
635 fprintf(o, "%s%06o %s %d\t%s\n",
636 label,
637 ce->ce_mode,
638 sha1_to_hex(ce->sha1),
639 ce_stage(ce),
640 ce->name);
641}
642#endif
643int threeway_merge(struct cache_entry **stages,
645 struct unpack_trees_options *o,
646 int remove)
647{
648 struct cache_entry *index;
649 struct cache_entry *head;
650 struct cache_entry *remote = stages[o->head_idx + 1];
651 int count;
652 int head_match = 0;
653 int remote_match = 0;
654 int df_conflict_head = 0;
656 int df_conflict_remote = 0;
657 int any_anc_missing = 0;
659 int no_anc_exists = 1;
660 int i;
661 for (i = 1; i < o->head_idx; i++) {
663 if (!stages[i] || stages[i] == o->df_conflict_entry)
664 any_anc_missing = 1;
665 else
666 no_anc_exists = 0;
667 }
668 index = stages[0];
670 head = stages[o->head_idx];
671 if (head == o->df_conflict_entry) {
673 df_conflict_head = 1;
674 head = NULL;
675 }
676 if (remote == o->df_conflict_entry) {
678 df_conflict_remote = 1;
679 remote = NULL;
680 }
681 /* First, if there's a #16 situation, note that to prevent #13
683 * and #14.
684 */
685 if (!same(remote, head)) {
686 for (i = 1; i < o->head_idx; i++) {
687 if (same(stages[i], head)) {
688 head_match = i;
689 }
690 if (same(stages[i], remote)) {
691 remote_match = i;
692 }
693 }
694 }
695 /* We start with cases where the index is allowed to match
697 * something other than the head: #14(ALT) and #2ALT, where it
698 * is permitted to match the result instead.
699 */
700 /* #14, #14ALT, #2ALT */
701 if (remote && !df_conflict_head && head_match && !remote_match) {
702 if (index && !same(index, remote) && !same(index, head))
703 reject_merge(index);
704 return merged_entry(remote, index, o);
705 }
706 /*
707 * If we have an entry in the index cache, then we want to
708 * make sure that it matches head.
709 */
710 if (index && !same(index, head)) {
711 reject_merge(index);
712 }
713 if (head) {
715 /* #5ALT, #15 */
716 if (same(head, remote))
717 return merged_entry(head, index, o);
718 /* #13, #3ALT */
719 if (!df_conflict_remote && remote_match && !head_match)
720 return merged_entry(head, index, o);
721 }
722 /* #1 */
724 if (!head && !remote && any_anc_missing) {
725 remove_entry(remove);
726 return 0;
727 }
728 /* Under the new "aggressive" rule, we resolve mostly trivial
730 * cases that we historically had git-merge-one-file resolve.
731 */
732 if (o->aggressive) {
733 int head_deleted = !head && !df_conflict_head;
734 int remote_deleted = !remote && !df_conflict_remote;
735 struct cache_entry *ce = NULL;
736 if (index)
738 ce = index;
739 else if (head)
740 ce = head;
741 else if (remote)
742 ce = remote;
743 else {
744 for (i = 1; i < o->head_idx; i++) {
745 if (stages[i] && stages[i] != o->df_conflict_entry) {
746 ce = stages[i];
747 break;
748 }
749 }
750 }
751 /*
753 * Deleted in both.
754 * Deleted in one and unchanged in the other.
755 */
756 if ((head_deleted && remote_deleted) ||
757 (head_deleted && remote && remote_match) ||
758 (remote_deleted && head && head_match)) {
759 remove_entry(remove);
760 if (index)
761 return deleted_entry(index, index, o);
762 else if (ce && !head_deleted)
763 verify_absent(ce, "removed", o);
764 return 0;
765 }
766 /*
767 * Added in both, identically.
768 */
769 if (no_anc_exists && head && remote && same(head, remote))
770 return merged_entry(head, index, o);
771 }
773 /* Below are "no merge" cases, which require that the index be
775 * up-to-date to avoid the files getting overwritten with
776 * conflict resolution files.
777 */
778 if (index) {
779 verify_uptodate(index, o);
780 }
781 remove_entry(remove);
783 o->nontrivial_merge = 1;
784 /* #2, #3, #4, #6, #7, #9, #10, #11. */
786 count = 0;
787 if (!head_match || !remote_match) {
788 for (i = 1; i < o->head_idx; i++) {
789 if (stages[i] && stages[i] != o->df_conflict_entry) {
790 keep_entry(stages[i], o);
791 count++;
792 break;
793 }
794 }
795 }
796#if DBRT_DEBUG
797 else {
798 fprintf(stderr, "read-tree: warning #16 detected\n");
799 show_stage_entry(stderr, "head ", stages[head_match]);
800 show_stage_entry(stderr, "remote ", stages[remote_match]);
801 }
802#endif
803 if (head) { count += keep_entry(head, o); }
804 if (remote) { count += keep_entry(remote, o); }
805 return count;
806}
807/*
809 * Two-way merge.
810 *
811 * The rule is to "carry forward" what is in the index without losing
812 * information across a "fast forward", favoring a successful merge
813 * over a merge failure when it makes sense. For details of the
814 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
815 *
816 */
817int twoway_merge(struct cache_entry **src,
818 struct unpack_trees_options *o,
819 int remove)
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 remove_entry(remove);
848 return deleted_entry(oldtree, current, o);
849 }
850 else if (oldtree && newtree &&
851 same(current, oldtree) && !same(current, newtree)) {
852 /* 20 or 21 */
853 return merged_entry(newtree, current, o);
854 }
855 else {
856 /* all other failures */
857 remove_entry(remove);
858 if (oldtree)
859 reject_merge(oldtree);
860 if (current)
861 reject_merge(current);
862 if (newtree)
863 reject_merge(newtree);
864 return -1;
865 }
866 }
867 else if (newtree)
868 return merged_entry(newtree, current, o);
869 remove_entry(remove);
870 return deleted_entry(oldtree, current, o);
871}
872/*
874 * Bind merge.
875 *
876 * Keep the index entries at stage0, collapse stage1 but make sure
877 * stage0 does not have anything there.
878 */
879int bind_merge(struct cache_entry **src,
880 struct unpack_trees_options *o,
881 int remove)
882{
883 struct cache_entry *old = src[0];
884 struct cache_entry *a = src[1];
885 if (o->merge_size != 1)
887 return error("Cannot do a bind merge of %d trees\n",
888 o->merge_size);
889 if (a && old)
890 die("Entry '%s' overlaps. Cannot bind.", a->name);
891 if (!a)
892 return keep_entry(old, o);
893 else
894 return merged_entry(a, NULL, o);
895}
896/*
898 * One-way merge.
899 *
900 * The rule is:
901 * - take the stat information from stage0, take the data from stage1
902 */
903int oneway_merge(struct cache_entry **src,
904 struct unpack_trees_options *o,
905 int remove)
906{
907 struct cache_entry *old = src[0];
908 struct cache_entry *a = src[1];
909 if (o->merge_size != 1)
911 return error("Cannot do a oneway merge of %d trees",
912 o->merge_size);
913 if (!a) {
915 remove_entry(remove);
916 return deleted_entry(old, old, o);
917 }
918 if (old && same(old, a)) {
919 if (o->reset) {
920 struct stat st;
921 if (lstat(old->name, &st) ||
922 ce_match_stat(old, &st, CE_MATCH_IGNORE_VALID))
923 old->ce_flags |= CE_UPDATE;
924 }
925 return keep_entry(old, o);
926 }
927 return merged_entry(a, old, o);
928}