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 i_stk = i_stk;
75 int retval = 0;
76 if (o->dir)
78 i_stk = push_exclude_per_directory(o->dir, base, strlen(base));
79 do {
81 int i;
82 const char *first;
83 int firstdir = 0;
84 int pathlen;
85 unsigned ce_size;
86 struct tree_entry_list **subposns;
87 struct cache_entry **src;
88 int any_files = 0;
89 int any_dirs = 0;
90 char *cache_name;
91 int ce_stage;
92 /* Find the first name in the input. */
94 first = NULL;
96 cache_name = NULL;
97 /* Check the cache */
99 if (o->merge && o->pos < active_nr) {
100 /* This is a bit tricky: */
101 /* If the index has a subdirectory (with
102 * contents) as the first name, it'll get a
103 * filename like "foo/bar". But that's after
104 * "foo", so the entry in trees will get
105 * handled first, at which point we'll go into
106 * "foo", and deal with "bar" from the index,
107 * because the base will be "foo/". The only
108 * way we can actually have "foo/bar" first of
109 * all the things is if the trees don't
110 * contain "foo" at all, in which case we'll
111 * handle "foo/bar" without going into the
112 * directory, but that's fine (and will return
113 * an error anyway, with the added unknown
114 * file case.
115 */
116 cache_name = active_cache[o->pos]->name;
118 if (strlen(cache_name) > baselen &&
119 !memcmp(cache_name, base, baselen)) {
120 cache_name += baselen;
121 first = cache_name;
122 } else {
123 cache_name = NULL;
124 }
125 }
126#if DBRT_DEBUG > 1
128 if (first)
129 printf("index %s\n", first);
130#endif
131 for (i = 0; i < len; i++) {
132 if (!posns[i] || posns[i] == df_conflict_list)
133 continue;
134#if DBRT_DEBUG > 1
135 printf("%d %s\n", i + 1, posns[i]->name);
136#endif
137 if (!first || entcmp(first, firstdir,
138 posns[i]->name,
139 S_ISDIR(posns[i]->mode)) > 0) {
140 first = posns[i]->name;
141 firstdir = S_ISDIR(posns[i]->mode);
142 }
143 }
144 /* No name means we're done */
145 if (!first)
146 goto leave_directory;
147 pathlen = strlen(first);
149 ce_size = cache_entry_size(baselen + pathlen);
150 src = xcalloc(src_size, sizeof(struct cache_entry *));
152 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
154 remove = -1;
156 if (cache_name && !strcmp(cache_name, first)) {
157 any_files = 1;
158 src[0] = active_cache[o->pos];
159 remove = o->pos;
160 }
161 for (i = 0; i < len; i++) {
163 struct cache_entry *ce;
164 if (!posns[i] ||
166 (posns[i] != df_conflict_list &&
167 strcmp(first, posns[i]->name))) {
168 continue;
169 }
170 if (posns[i] == df_conflict_list) {
172 src[i + o->merge] = o->df_conflict_entry;
173 continue;
174 }
175 if (S_ISDIR(posns[i]->mode)) {
177 struct tree *tree = lookup_tree(posns[i]->sha1);
178 struct tree_desc t;
179 any_dirs = 1;
180 parse_tree(tree);
181 init_tree_desc(&t, tree->buffer, tree->size);
182 subposns[i] = create_tree_entry_list(&t);
183 posns[i] = posns[i]->next;
184 src[i + o->merge] = o->df_conflict_entry;
185 continue;
186 }
187 if (!o->merge)
189 ce_stage = 0;
190 else if (i + 1 < o->head_idx)
191 ce_stage = 1;
192 else if (i + 1 > o->head_idx)
193 ce_stage = 3;
194 else
195 ce_stage = 2;
196 ce = xcalloc(1, ce_size);
198 ce->ce_mode = create_ce_mode(posns[i]->mode);
199 ce->ce_flags = create_ce_flags(baselen + pathlen,
200 ce_stage);
201 memcpy(ce->name, base, baselen);
202 memcpy(ce->name + baselen, first, pathlen + 1);
203 any_files = 1;
205 hashcpy(ce->sha1, posns[i]->sha1);
207 src[i + o->merge] = ce;
208 subposns[i] = df_conflict_list;
209 posns[i] = posns[i]->next;
210 }
211 if (any_files) {
212 if (o->merge) {
213 int ret;
214#if DBRT_DEBUG > 1
216 printf("%s:\n", first);
217 for (i = 0; i < src_size; i++) {
218 printf(" %d ", i);
219 if (src[i])
220 printf("%s\n", sha1_to_hex(src[i]->sha1));
221 else
222 printf("\n");
223 }
224#endif
225 ret = o->fn(src, o, remove);
226#if DBRT_DEBUG > 1
228 printf("Added %d entries\n", ret);
229#endif
230 o->pos += ret;
231 } else {
232 remove_entry(remove);
233 for (i = 0; i < src_size; i++) {
234 if (src[i]) {
235 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
236 }
237 }
238 }
239 }
240 if (any_dirs) {
241 char *newbase = xmalloc(baselen + 2 + pathlen);
242 memcpy(newbase, base, baselen);
243 memcpy(newbase + baselen, first, pathlen);
244 newbase[baselen + pathlen] = '/';
245 newbase[baselen + pathlen + 1] = '\0';
246 if (unpack_trees_rec(subposns, len, newbase, o,
247 df_conflict_list)) {
248 retval = -1;
249 goto leave_directory;
250 }
251 free(newbase);
252 }
253 free(subposns);
254 free(src);
255 } while (1);
256 leave_directory:
258 if (o->dir)
259 pop_exclude_per_directory(o->dir, i_stk);
260 return retval;
261}
262/* Unlink the last component and attempt to remove leading
264 * directories, in case this unlink is the removal of the
265 * last entry in the directory -- empty directories are removed.
266 */
267static void unlink_entry(char *name, char *last_symlink)
268{
269 char *cp, *prev;
270 if (has_symlink_leading_path(name, last_symlink))
272 return;
273 if (unlink(name))
274 return;
275 prev = NULL;
276 while (1) {
277 int status;
278 cp = strrchr(name, '/');
279 if (prev)
280 *prev = '/';
281 if (!cp)
282 break;
283 *cp = 0;
285 status = rmdir(name);
286 if (status) {
287 *cp = '/';
288 break;
289 }
290 prev = cp;
291 }
292}
293static struct checkout state;
295static void check_updates(struct cache_entry **src, int nr,
296 struct unpack_trees_options *o)
297{
298 unsigned short mask = htons(CE_UPDATE);
299 unsigned cnt = 0, total = 0;
300 struct progress progress;
301 char last_symlink[PATH_MAX];
302 if (o->update && o->verbose_update) {
304 for (total = cnt = 0; cnt < nr; cnt++) {
305 struct cache_entry *ce = src[cnt];
306 if (!ce->ce_mode || ce->ce_flags & mask)
307 total++;
308 }
309 start_progress_delay(&progress, "Checking %u files out...",
311 "", total, 50, 2);
312 cnt = 0;
313 }
314 *last_symlink = '\0';
316 while (nr--) {
317 struct cache_entry *ce = *src++;
318 if (total)
320 if (!ce->ce_mode || ce->ce_flags & mask)
321 display_progress(&progress, ++cnt);
322 if (!ce->ce_mode) {
323 if (o->update)
324 unlink_entry(ce->name, last_symlink);
325 continue;
326 }
327 if (ce->ce_flags & mask) {
328 ce->ce_flags &= ~mask;
329 if (o->update) {
330 checkout_entry(ce, &state, NULL);
331 *last_symlink = '\0';
332 }
333 }
334 }
335 if (total)
336 stop_progress(&progress);;
337}
338int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
340{
341 struct tree_entry_list **posns;
342 int i;
343 struct tree_entry_list df_conflict_list;
344 static struct cache_entry *dfc;
345 memset(&df_conflict_list, 0, sizeof(df_conflict_list));
347 df_conflict_list.next = &df_conflict_list;
348 memset(&state, 0, sizeof(state));
349 state.base_dir = "";
350 state.force = 1;
351 state.quiet = 1;
352 state.refresh_cache = 1;
353 o->merge_size = len;
355 if (!dfc)
357 dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
358 o->df_conflict_entry = dfc;
359 if (len) {
361 posns = xmalloc(len * sizeof(struct tree_entry_list *));
362 for (i = 0; i < len; i++)
363 posns[i] = create_tree_entry_list(t+i);
364 if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
366 o, &df_conflict_list))
367 return -1;
368 }
369 if (o->trivial_merges_only && o->nontrivial_merge)
371 die("Merge requires file-level merging");
372 check_updates(active_cache, active_nr, o);
374 return 0;
375}
376/* Here come the merge functions */
378static void reject_merge(struct cache_entry *ce)
380{
381 die("Entry '%s' would be overwritten by merge. Cannot merge.",
382 ce->name);
383}
384static int same(struct cache_entry *a, struct cache_entry *b)
386{
387 if (!!a != !!b)
388 return 0;
389 if (!a && !b)
390 return 1;
391 return a->ce_mode == b->ce_mode &&
392 !hashcmp(a->sha1, b->sha1);
393}
394/*
397 * When a CE gets turned into an unmerged entry, we
398 * want it to be up-to-date
399 */
400static void verify_uptodate(struct cache_entry *ce,
401 struct unpack_trees_options *o)
402{
403 struct stat st;
404 if (o->index_only || o->reset)
406 return;
407 if (!lstat(ce->name, &st)) {
409 unsigned changed = ce_match_stat(ce, &st, 1);
410 if (!changed)
411 return;
412 /*
413 * NEEDSWORK: the current default policy is to allow
414 * submodule to be out of sync wrt the supermodule
415 * index. This needs to be tightened later for
416 * submodules that are marked to be automatically
417 * checked out.
418 */
419 if (S_ISGITLINK(ntohl(ce->ce_mode)))
420 return;
421 errno = 0;
422 }
423 if (errno == ENOENT)
424 return;
425 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
426}
427static void invalidate_ce_path(struct cache_entry *ce)
429{
430 if (ce)
431 cache_tree_invalidate_path(active_cache_tree, ce->name);
432}
433/*
435 * Check that checking out ce->sha1 in subdir ce->name is not
436 * going to overwrite any working files.
437 *
438 * Currently, git does not checkout subprojects during a superproject
439 * checkout, so it is not going to overwrite anything.
440 */
441static int verify_clean_submodule(struct cache_entry *ce, const char *action,
442 struct unpack_trees_options *o)
443{
444 return 0;
445}
446static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
448 struct unpack_trees_options *o)
449{
450 /*
451 * we are about to extract "ce->name"; we would not want to lose
452 * anything in the existing directory there.
453 */
454 int namelen;
455 int pos, i;
456 struct dir_struct d;
457 char *pathbuf;
458 int cnt = 0;
459 unsigned char sha1[20];
460 if (S_ISGITLINK(ntohl(ce->ce_mode)) &&
462 resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
463 /* If we are not going to update the submodule, then
464 * we don't care.
465 */
466 if (!hashcmp(sha1, ce->sha1))
467 return 0;
468 return verify_clean_submodule(ce, action, o);
469 }
470 /*
472 * First let's make sure we do not have a local modification
473 * in that directory.
474 */
475 namelen = strlen(ce->name);
476 pos = cache_name_pos(ce->name, namelen);
477 if (0 <= pos)
478 return cnt; /* we have it as nondirectory */
479 pos = -pos - 1;
480 for (i = pos; i < active_nr; i++) {
481 struct cache_entry *ce = active_cache[i];
482 int len = ce_namelen(ce);
483 if (len < namelen ||
484 strncmp(ce->name, ce->name, namelen) ||
485 ce->name[namelen] != '/')
486 break;
487 /*
488 * ce->name is an entry in the subdirectory.
489 */
490 if (!ce_stage(ce)) {
491 verify_uptodate(ce, o);
492 ce->ce_mode = 0;
493 }
494 cnt++;
495 }
496 /*
498 * Then we need to make sure that we do not lose a locally
499 * present file that is not ignored.
500 */
501 pathbuf = xmalloc(namelen + 2);
502 memcpy(pathbuf, ce->name, namelen);
503 strcpy(pathbuf+namelen, "/");
504 memset(&d, 0, sizeof(d));
506 if (o->dir)
507 d.exclude_per_dir = o->dir->exclude_per_dir;
508 i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
509 if (i)
510 die("Updating '%s' would lose untracked files in it",
511 ce->name);
512 free(pathbuf);
513 return cnt;
514}
515/*
517 * We do not want to remove or overwrite a working tree file that
518 * is not tracked, unless it is ignored.
519 */
520static void verify_absent(struct cache_entry *ce, const char *action,
521 struct unpack_trees_options *o)
522{
523 struct stat st;
524 if (o->index_only || o->reset || !o->update)
526 return;
527 if (has_symlink_leading_path(ce->name, NULL))
529 return;
530 if (!lstat(ce->name, &st)) {
532 int cnt;
533 if (o->dir && excluded(o->dir, ce->name))
535 /*
536 * ce->name is explicitly excluded, so it is Ok to
537 * overwrite it.
538 */
539 return;
540 if (S_ISDIR(st.st_mode)) {
541 /*
542 * We are checking out path "foo" and
543 * found "foo/." in the working tree.
544 * This is tricky -- if we have modified
545 * files that are in "foo/" we would lose
546 * it.
547 */
548 cnt = verify_clean_subdirectory(ce, action, o);
549 /*
551 * If this removed entries from the index,
552 * what that means is:
553 *
554 * (1) the caller unpack_trees_rec() saw path/foo
555 * in the index, and it has not removed it because
556 * it thinks it is handling 'path' as blob with
557 * D/F conflict;
558 * (2) we will return "ok, we placed a merged entry
559 * in the index" which would cause o->pos to be
560 * incremented by one;
561 * (3) however, original o->pos now has 'path/foo'
562 * marked with "to be removed".
563 *
564 * We need to increment it by the number of
565 * deleted entries here.
566 */
567 o->pos += cnt;
568 return;
569 }
570 /*
572 * The previous round may already have decided to
573 * delete this path, which is in a subdirectory that
574 * is being replaced with a blob.
575 */
576 cnt = cache_name_pos(ce->name, strlen(ce->name));
577 if (0 <= cnt) {
578 struct cache_entry *ce = active_cache[cnt];
579 if (!ce_stage(ce) && !ce->ce_mode)
580 return;
581 }
582 die("Untracked working tree file '%s' "
584 "would be %s by merge.", ce->name, action);
585 }
586}
587static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
589 struct unpack_trees_options *o)
590{
591 merge->ce_flags |= htons(CE_UPDATE);
592 if (old) {
593 /*
594 * See if we can re-use the old CE directly?
595 * That way we get the uptodate stat info.
596 *
597 * This also removes the UPDATE flag on
598 * a match.
599 */
600 if (same(old, merge)) {
601 *merge = *old;
602 } else {
603 verify_uptodate(old, o);
604 invalidate_ce_path(old);
605 }
606 }
607 else {
608 verify_absent(merge, "overwritten", o);
609 invalidate_ce_path(merge);
610 }
611 merge->ce_flags &= ~htons(CE_STAGEMASK);
613 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
614 return 1;
615}
616static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
618 struct unpack_trees_options *o)
619{
620 if (old)
621 verify_uptodate(old, o);
622 else
623 verify_absent(ce, "removed", o);
624 ce->ce_mode = 0;
625 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
626 invalidate_ce_path(ce);
627 return 1;
628}
629static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
631{
632 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
633 return 1;
634}
635#if DBRT_DEBUG
637static void show_stage_entry(FILE *o,
638 const char *label, const struct cache_entry *ce)
639{
640 if (!ce)
641 fprintf(o, "%s (missing)\n", label);
642 else
643 fprintf(o, "%s%06o %s %d\t%s\n",
644 label,
645 ntohl(ce->ce_mode),
646 sha1_to_hex(ce->sha1),
647 ce_stage(ce),
648 ce->name);
649}
650#endif
651int threeway_merge(struct cache_entry **stages,
653 struct unpack_trees_options *o,
654 int remove)
655{
656 struct cache_entry *index;
657 struct cache_entry *head;
658 struct cache_entry *remote = stages[o->head_idx + 1];
659 int count;
660 int head_match = 0;
661 int remote_match = 0;
662 int df_conflict_head = 0;
664 int df_conflict_remote = 0;
665 int any_anc_missing = 0;
667 int no_anc_exists = 1;
668 int i;
669 for (i = 1; i < o->head_idx; i++) {
671 if (!stages[i] || stages[i] == o->df_conflict_entry)
672 any_anc_missing = 1;
673 else
674 no_anc_exists = 0;
675 }
676 index = stages[0];
678 head = stages[o->head_idx];
679 if (head == o->df_conflict_entry) {
681 df_conflict_head = 1;
682 head = NULL;
683 }
684 if (remote == o->df_conflict_entry) {
686 df_conflict_remote = 1;
687 remote = NULL;
688 }
689 /* First, if there's a #16 situation, note that to prevent #13
691 * and #14.
692 */
693 if (!same(remote, head)) {
694 for (i = 1; i < o->head_idx; i++) {
695 if (same(stages[i], head)) {
696 head_match = i;
697 }
698 if (same(stages[i], remote)) {
699 remote_match = i;
700 }
701 }
702 }
703 /* We start with cases where the index is allowed to match
705 * something other than the head: #14(ALT) and #2ALT, where it
706 * is permitted to match the result instead.
707 */
708 /* #14, #14ALT, #2ALT */
709 if (remote && !df_conflict_head && head_match && !remote_match) {
710 if (index && !same(index, remote) && !same(index, head))
711 reject_merge(index);
712 return merged_entry(remote, index, o);
713 }
714 /*
715 * If we have an entry in the index cache, then we want to
716 * make sure that it matches head.
717 */
718 if (index && !same(index, head)) {
719 reject_merge(index);
720 }
721 if (head) {
723 /* #5ALT, #15 */
724 if (same(head, remote))
725 return merged_entry(head, index, o);
726 /* #13, #3ALT */
727 if (!df_conflict_remote && remote_match && !head_match)
728 return merged_entry(head, index, o);
729 }
730 /* #1 */
732 if (!head && !remote && any_anc_missing) {
733 remove_entry(remove);
734 return 0;
735 }
736 /* Under the new "aggressive" rule, we resolve mostly trivial
738 * cases that we historically had git-merge-one-file resolve.
739 */
740 if (o->aggressive) {
741 int head_deleted = !head && !df_conflict_head;
742 int remote_deleted = !remote && !df_conflict_remote;
743 struct cache_entry *ce = NULL;
744 if (index)
746 ce = index;
747 else if (head)
748 ce = head;
749 else if (remote)
750 ce = remote;
751 else {
752 for (i = 1; i < o->head_idx; i++) {
753 if (stages[i] && stages[i] != o->df_conflict_entry) {
754 ce = stages[i];
755 break;
756 }
757 }
758 }
759 /*
761 * Deleted in both.
762 * Deleted in one and unchanged in the other.
763 */
764 if ((head_deleted && remote_deleted) ||
765 (head_deleted && remote && remote_match) ||
766 (remote_deleted && head && head_match)) {
767 remove_entry(remove);
768 if (index)
769 return deleted_entry(index, index, o);
770 else if (ce && !head_deleted)
771 verify_absent(ce, "removed", o);
772 return 0;
773 }
774 /*
775 * Added in both, identically.
776 */
777 if (no_anc_exists && head && remote && same(head, remote))
778 return merged_entry(head, index, o);
779 }
781 /* Below are "no merge" cases, which require that the index be
783 * up-to-date to avoid the files getting overwritten with
784 * conflict resolution files.
785 */
786 if (index) {
787 verify_uptodate(index, o);
788 }
789 remove_entry(remove);
791 o->nontrivial_merge = 1;
792 /* #2, #3, #4, #6, #7, #9, #10, #11. */
794 count = 0;
795 if (!head_match || !remote_match) {
796 for (i = 1; i < o->head_idx; i++) {
797 if (stages[i] && stages[i] != o->df_conflict_entry) {
798 keep_entry(stages[i], o);
799 count++;
800 break;
801 }
802 }
803 }
804#if DBRT_DEBUG
805 else {
806 fprintf(stderr, "read-tree: warning #16 detected\n");
807 show_stage_entry(stderr, "head ", stages[head_match]);
808 show_stage_entry(stderr, "remote ", stages[remote_match]);
809 }
810#endif
811 if (head) { count += keep_entry(head, o); }
812 if (remote) { count += keep_entry(remote, o); }
813 return count;
814}
815/*
817 * Two-way merge.
818 *
819 * The rule is to "carry forward" what is in the index without losing
820 * information across a "fast forward", favoring a successful merge
821 * over a merge failure when it makes sense. For details of the
822 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
823 *
824 */
825int twoway_merge(struct cache_entry **src,
826 struct unpack_trees_options *o,
827 int remove)
828{
829 struct cache_entry *current = src[0];
830 struct cache_entry *oldtree = src[1];
831 struct cache_entry *newtree = src[2];
832 if (o->merge_size != 2)
834 return error("Cannot do a twoway merge of %d trees",
835 o->merge_size);
836 if (oldtree == o->df_conflict_entry)
838 oldtree = NULL;
839 if (newtree == o->df_conflict_entry)
840 newtree = NULL;
841 if (current) {
843 if ((!oldtree && !newtree) || /* 4 and 5 */
844 (!oldtree && newtree &&
845 same(current, newtree)) || /* 6 and 7 */
846 (oldtree && newtree &&
847 same(oldtree, newtree)) || /* 14 and 15 */
848 (oldtree && newtree &&
849 !same(oldtree, newtree) && /* 18 and 19 */
850 same(current, newtree))) {
851 return keep_entry(current, o);
852 }
853 else if (oldtree && !newtree && same(current, oldtree)) {
854 /* 10 or 11 */
855 remove_entry(remove);
856 return deleted_entry(oldtree, current, o);
857 }
858 else if (oldtree && newtree &&
859 same(current, oldtree) && !same(current, newtree)) {
860 /* 20 or 21 */
861 return merged_entry(newtree, current, o);
862 }
863 else {
864 /* all other failures */
865 remove_entry(remove);
866 if (oldtree)
867 reject_merge(oldtree);
868 if (current)
869 reject_merge(current);
870 if (newtree)
871 reject_merge(newtree);
872 return -1;
873 }
874 }
875 else if (newtree)
876 return merged_entry(newtree, current, o);
877 remove_entry(remove);
878 return deleted_entry(oldtree, current, o);
879}
880/*
882 * Bind merge.
883 *
884 * Keep the index entries at stage0, collapse stage1 but make sure
885 * stage0 does not have anything there.
886 */
887int bind_merge(struct cache_entry **src,
888 struct unpack_trees_options *o,
889 int remove)
890{
891 struct cache_entry *old = src[0];
892 struct cache_entry *a = src[1];
893 if (o->merge_size != 1)
895 return error("Cannot do a bind merge of %d trees\n",
896 o->merge_size);
897 if (a && old)
898 die("Entry '%s' overlaps. Cannot bind.", a->name);
899 if (!a)
900 return keep_entry(old, o);
901 else
902 return merged_entry(a, NULL, o);
903}
904/*
906 * One-way merge.
907 *
908 * The rule is:
909 * - take the stat information from stage0, take the data from stage1
910 */
911int oneway_merge(struct cache_entry **src,
912 struct unpack_trees_options *o,
913 int remove)
914{
915 struct cache_entry *old = src[0];
916 struct cache_entry *a = src[1];
917 if (o->merge_size != 1)
919 return error("Cannot do a oneway merge of %d trees",
920 o->merge_size);
921 if (!a) {
923 remove_entry(remove);
924 return deleted_entry(old, old, o);
925 }
926 if (old && same(old, a)) {
927 if (o->reset) {
928 struct stat st;
929 if (lstat(old->name, &st) ||
930 ce_match_stat(old, &st, 1))
931 old->ce_flags |= htons(CE_UPDATE);
932 }
933 return keep_entry(old, o);
934 }
935 return merged_entry(a, old, o);
936}