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#define DBRT_DEBUG 1
10struct tree_entry_list {
12 struct tree_entry_list *next;
13 unsigned directory : 1;
14 unsigned executable : 1;
15 unsigned symlink : 1;
16 unsigned int mode;
17 const char *name;
18 const unsigned char *sha1;
19};
20static struct tree_entry_list *create_tree_entry_list(struct tree *tree)
22{
23 struct tree_desc desc;
24 struct name_entry one;
25 struct tree_entry_list *ret = NULL;
26 struct tree_entry_list **list_p = &ret;
27 if (!tree->object.parsed)
29 parse_tree(tree);
30 init_tree_desc(&desc, tree->buffer, tree->size);
32 while (tree_entry(&desc, &one)) {
34 struct tree_entry_list *entry;
35 entry = xmalloc(sizeof(struct tree_entry_list));
37 entry->name = one.path;
38 entry->sha1 = one.sha1;
39 entry->mode = one.mode;
40 entry->directory = S_ISDIR(one.mode) != 0;
41 entry->executable = (one.mode & S_IXUSR) != 0;
42 entry->symlink = S_ISLNK(one.mode) != 0;
43 entry->next = NULL;
44 *list_p = entry;
46 list_p = &entry->next;
47 }
48 return ret;
49}
50static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
52{
53 int len1 = strlen(name1);
54 int len2 = strlen(name2);
55 int len = len1 < len2 ? len1 : len2;
56 int ret = memcmp(name1, name2, len);
57 unsigned char c1, c2;
58 if (ret)
59 return ret;
60 c1 = name1[len];
61 c2 = name2[len];
62 if (!c1 && dir1)
63 c1 = '/';
64 if (!c2 && dir2)
65 c2 = '/';
66 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
67 if (c1 && c2 && !ret)
68 ret = len1 - len2;
69 return ret;
70}
71static int unpack_trees_rec(struct tree_entry_list **posns, int len,
73 const char *base, struct unpack_trees_options *o,
74 struct tree_entry_list *df_conflict_list)
75{
76 int baselen = strlen(base);
77 int src_size = len + 1;
78 int i_stk = i_stk;
79 int retval = 0;
80 if (o->dir)
82 i_stk = push_exclude_per_directory(o->dir, base, strlen(base));
83 do {
85 int i;
86 const char *first;
87 int firstdir = 0;
88 int pathlen;
89 unsigned ce_size;
90 struct tree_entry_list **subposns;
91 struct cache_entry **src;
92 int any_files = 0;
93 int any_dirs = 0;
94 char *cache_name;
95 int ce_stage;
96 /* Find the first name in the input. */
98 first = NULL;
100 cache_name = NULL;
101 /* Check the cache */
103 if (o->merge && o->pos < active_nr) {
104 /* This is a bit tricky: */
105 /* If the index has a subdirectory (with
106 * contents) as the first name, it'll get a
107 * filename like "foo/bar". But that's after
108 * "foo", so the entry in trees will get
109 * handled first, at which point we'll go into
110 * "foo", and deal with "bar" from the index,
111 * because the base will be "foo/". The only
112 * way we can actually have "foo/bar" first of
113 * all the things is if the trees don't
114 * contain "foo" at all, in which case we'll
115 * handle "foo/bar" without going into the
116 * directory, but that's fine (and will return
117 * an error anyway, with the added unknown
118 * file case.
119 */
120 cache_name = active_cache[o->pos]->name;
122 if (strlen(cache_name) > baselen &&
123 !memcmp(cache_name, base, baselen)) {
124 cache_name += baselen;
125 first = cache_name;
126 } else {
127 cache_name = NULL;
128 }
129 }
130#if DBRT_DEBUG > 1
132 if (first)
133 printf("index %s\n", first);
134#endif
135 for (i = 0; i < len; i++) {
136 if (!posns[i] || posns[i] == df_conflict_list)
137 continue;
138#if DBRT_DEBUG > 1
139 printf("%d %s\n", i + 1, posns[i]->name);
140#endif
141 if (!first || entcmp(first, firstdir,
142 posns[i]->name,
143 posns[i]->directory) > 0) {
144 first = posns[i]->name;
145 firstdir = posns[i]->directory;
146 }
147 }
148 /* No name means we're done */
149 if (!first)
150 goto leave_directory;
151 pathlen = strlen(first);
153 ce_size = cache_entry_size(baselen + pathlen);
154 src = xcalloc(src_size, sizeof(struct cache_entry *));
156 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
158 if (cache_name && !strcmp(cache_name, first)) {
160 any_files = 1;
161 src[0] = active_cache[o->pos];
162 remove_cache_entry_at(o->pos);
163 }
164 for (i = 0; i < len; i++) {
166 struct cache_entry *ce;
167 if (!posns[i] ||
169 (posns[i] != df_conflict_list &&
170 strcmp(first, posns[i]->name))) {
171 continue;
172 }
173 if (posns[i] == df_conflict_list) {
175 src[i + o->merge] = o->df_conflict_entry;
176 continue;
177 }
178 if (posns[i]->directory) {
180 struct tree *tree = lookup_tree(posns[i]->sha1);
181 any_dirs = 1;
182 parse_tree(tree);
183 subposns[i] = create_tree_entry_list(tree);
184 posns[i] = posns[i]->next;
185 src[i + o->merge] = o->df_conflict_entry;
186 continue;
187 }
188 if (!o->merge)
190 ce_stage = 0;
191 else if (i + 1 < o->head_idx)
192 ce_stage = 1;
193 else if (i + 1 > o->head_idx)
194 ce_stage = 3;
195 else
196 ce_stage = 2;
197 ce = xcalloc(1, ce_size);
199 ce->ce_mode = create_ce_mode(posns[i]->mode);
200 ce->ce_flags = create_ce_flags(baselen + pathlen,
201 ce_stage);
202 memcpy(ce->name, base, baselen);
203 memcpy(ce->name + baselen, first, pathlen + 1);
204 any_files = 1;
206 hashcpy(ce->sha1, posns[i]->sha1);
208 src[i + o->merge] = ce;
209 subposns[i] = df_conflict_list;
210 posns[i] = posns[i]->next;
211 }
212 if (any_files) {
213 if (o->merge) {
214 int ret;
215#if DBRT_DEBUG > 1
217 printf("%s:\n", first);
218 for (i = 0; i < src_size; i++) {
219 printf(" %d ", i);
220 if (src[i])
221 printf("%s\n", sha1_to_hex(src[i]->sha1));
222 else
223 printf("\n");
224 }
225#endif
226 ret = o->fn(src, o);
227#if DBRT_DEBUG > 1
229 printf("Added %d entries\n", ret);
230#endif
231 o->pos += ret;
232 } else {
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(struct object_list *trees, struct unpack_trees_options *o)
340{
341 unsigned len = object_list_length(trees);
342 struct tree_entry_list **posns;
343 int i;
344 struct object_list *posn = trees;
345 struct tree_entry_list df_conflict_list;
346 static struct cache_entry *dfc;
347 memset(&df_conflict_list, 0, sizeof(df_conflict_list));
349 df_conflict_list.next = &df_conflict_list;
350 memset(&state, 0, sizeof(state));
351 state.base_dir = "";
352 state.force = 1;
353 state.quiet = 1;
354 state.refresh_cache = 1;
355 o->merge_size = len;
357 if (!dfc)
359 dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
360 o->df_conflict_entry = dfc;
361 if (len) {
363 posns = xmalloc(len * sizeof(struct tree_entry_list *));
364 for (i = 0; i < len; i++) {
365 posns[i] = create_tree_entry_list((struct tree *) posn->item);
366 posn = posn->next;
367 }
368 if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
369 o, &df_conflict_list))
370 return -1;
371 }
372 if (o->trivial_merges_only && o->nontrivial_merge)
374 die("Merge requires file-level merging");
375 check_updates(active_cache, active_nr, o);
377 return 0;
378}
379/* Here come the merge functions */
381static void reject_merge(struct cache_entry *ce)
383{
384 die("Entry '%s' would be overwritten by merge. Cannot merge.",
385 ce->name);
386}
387static int same(struct cache_entry *a, struct cache_entry *b)
389{
390 if (!!a != !!b)
391 return 0;
392 if (!a && !b)
393 return 1;
394 return a->ce_mode == b->ce_mode &&
395 !hashcmp(a->sha1, b->sha1);
396}
397/*
400 * When a CE gets turned into an unmerged entry, we
401 * want it to be up-to-date
402 */
403static void verify_uptodate(struct cache_entry *ce,
404 struct unpack_trees_options *o)
405{
406 struct stat st;
407 if (o->index_only || o->reset)
409 return;
410 if (!lstat(ce->name, &st)) {
412 unsigned changed = ce_match_stat(ce, &st, 1);
413 if (!changed)
414 return;
415 errno = 0;
416 }
417 if (o->reset) {
418 ce->ce_flags |= htons(CE_UPDATE);
419 return;
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}
431static int verify_clean_subdirectory(const char *path, const char *action,
433 struct unpack_trees_options *o)
434{
435 /*
436 * we are about to extract "path"; we would not want to lose
437 * anything in the existing directory there.
438 */
439 int namelen;
440 int pos, i;
441 struct dir_struct d;
442 char *pathbuf;
443 int cnt = 0;
444 /*
446 * First let's make sure we do not have a local modification
447 * in that directory.
448 */
449 namelen = strlen(path);
450 pos = cache_name_pos(path, namelen);
451 if (0 <= pos)
452 return cnt; /* we have it as nondirectory */
453 pos = -pos - 1;
454 for (i = pos; i < active_nr; i++) {
455 struct cache_entry *ce = active_cache[i];
456 int len = ce_namelen(ce);
457 if (len < namelen ||
458 strncmp(path, ce->name, namelen) ||
459 ce->name[namelen] != '/')
460 break;
461 /*
462 * ce->name is an entry in the subdirectory.
463 */
464 if (!ce_stage(ce)) {
465 verify_uptodate(ce, o);
466 ce->ce_mode = 0;
467 }
468 cnt++;
469 }
470 /*
472 * Then we need to make sure that we do not lose a locally
473 * present file that is not ignored.
474 */
475 pathbuf = xmalloc(namelen + 2);
476 memcpy(pathbuf, path, namelen);
477 strcpy(pathbuf+namelen, "/");
478 memset(&d, 0, sizeof(d));
480 if (o->dir)
481 d.exclude_per_dir = o->dir->exclude_per_dir;
482 i = read_directory(&d, path, pathbuf, namelen+1, NULL);
483 if (i)
484 die("Updating '%s' would lose untracked files in it",
485 path);
486 free(pathbuf);
487 return cnt;
488}
489/*
491 * We do not want to remove or overwrite a working tree file that
492 * is not tracked, unless it is ignored.
493 */
494static void verify_absent(const char *path, const char *action,
495 struct unpack_trees_options *o)
496{
497 struct stat st;
498 if (o->index_only || o->reset || !o->update)
500 return;
501 if (!lstat(path, &st)) {
503 int cnt;
504 if (o->dir && excluded(o->dir, path))
506 /*
507 * path is explicitly excluded, so it is Ok to
508 * overwrite it.
509 */
510 return;
511 if (S_ISDIR(st.st_mode)) {
512 /*
513 * We are checking out path "foo" and
514 * found "foo/." in the working tree.
515 * This is tricky -- if we have modified
516 * files that are in "foo/" we would lose
517 * it.
518 */
519 cnt = verify_clean_subdirectory(path, action, o);
520 /*
522 * If this removed entries from the index,
523 * what that means is:
524 *
525 * (1) the caller unpack_trees_rec() saw path/foo
526 * in the index, and it has not removed it because
527 * it thinks it is handling 'path' as blob with
528 * D/F conflict;
529 * (2) we will return "ok, we placed a merged entry
530 * in the index" which would cause o->pos to be
531 * incremented by one;
532 * (3) however, original o->pos now has 'path/foo'
533 * marked with "to be removed".
534 *
535 * We need to increment it by the number of
536 * deleted entries here.
537 */
538 o->pos += cnt;
539 return;
540 }
541 /*
543 * The previous round may already have decided to
544 * delete this path, which is in a subdirectory that
545 * is being replaced with a blob.
546 */
547 cnt = cache_name_pos(path, strlen(path));
548 if (0 <= cnt) {
549 struct cache_entry *ce = active_cache[cnt];
550 if (!ce_stage(ce) && !ce->ce_mode)
551 return;
552 }
553 die("Untracked working tree file '%s' "
555 "would be %s by merge.", path, action);
556 }
557}
558static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
560 struct unpack_trees_options *o)
561{
562 merge->ce_flags |= htons(CE_UPDATE);
563 if (old) {
564 /*
565 * See if we can re-use the old CE directly?
566 * That way we get the uptodate stat info.
567 *
568 * This also removes the UPDATE flag on
569 * a match.
570 */
571 if (same(old, merge)) {
572 *merge = *old;
573 } else {
574 verify_uptodate(old, o);
575 invalidate_ce_path(old);
576 }
577 }
578 else {
579 verify_absent(merge->name, "overwritten", o);
580 invalidate_ce_path(merge);
581 }
582 merge->ce_flags &= ~htons(CE_STAGEMASK);
584 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
585 return 1;
586}
587static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
589 struct unpack_trees_options *o)
590{
591 if (old)
592 verify_uptodate(old, o);
593 else
594 verify_absent(ce->name, "removed", o);
595 ce->ce_mode = 0;
596 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
597 invalidate_ce_path(ce);
598 return 1;
599}
600static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
602{
603 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
604 return 1;
605}
606#if DBRT_DEBUG
608static void show_stage_entry(FILE *o,
609 const char *label, const struct cache_entry *ce)
610{
611 if (!ce)
612 fprintf(o, "%s (missing)\n", label);
613 else
614 fprintf(o, "%s%06o %s %d\t%s\n",
615 label,
616 ntohl(ce->ce_mode),
617 sha1_to_hex(ce->sha1),
618 ce_stage(ce),
619 ce->name);
620}
621#endif
622int threeway_merge(struct cache_entry **stages,
624 struct unpack_trees_options *o)
625{
626 struct cache_entry *index;
627 struct cache_entry *head;
628 struct cache_entry *remote = stages[o->head_idx + 1];
629 int count;
630 int head_match = 0;
631 int remote_match = 0;
632 int df_conflict_head = 0;
634 int df_conflict_remote = 0;
635 int any_anc_missing = 0;
637 int no_anc_exists = 1;
638 int i;
639 for (i = 1; i < o->head_idx; i++) {
641 if (!stages[i] || stages[i] == o->df_conflict_entry)
642 any_anc_missing = 1;
643 else
644 no_anc_exists = 0;
645 }
646 index = stages[0];
648 head = stages[o->head_idx];
649 if (head == o->df_conflict_entry) {
651 df_conflict_head = 1;
652 head = NULL;
653 }
654 if (remote == o->df_conflict_entry) {
656 df_conflict_remote = 1;
657 remote = NULL;
658 }
659 /* First, if there's a #16 situation, note that to prevent #13
661 * and #14.
662 */
663 if (!same(remote, head)) {
664 for (i = 1; i < o->head_idx; i++) {
665 if (same(stages[i], head)) {
666 head_match = i;
667 }
668 if (same(stages[i], remote)) {
669 remote_match = i;
670 }
671 }
672 }
673 /* We start with cases where the index is allowed to match
675 * something other than the head: #14(ALT) and #2ALT, where it
676 * is permitted to match the result instead.
677 */
678 /* #14, #14ALT, #2ALT */
679 if (remote && !df_conflict_head && head_match && !remote_match) {
680 if (index && !same(index, remote) && !same(index, head))
681 reject_merge(index);
682 return merged_entry(remote, index, o);
683 }
684 /*
685 * If we have an entry in the index cache, then we want to
686 * make sure that it matches head.
687 */
688 if (index && !same(index, head)) {
689 reject_merge(index);
690 }
691 if (head) {
693 /* #5ALT, #15 */
694 if (same(head, remote))
695 return merged_entry(head, index, o);
696 /* #13, #3ALT */
697 if (!df_conflict_remote && remote_match && !head_match)
698 return merged_entry(head, index, o);
699 }
700 /* #1 */
702 if (!head && !remote && any_anc_missing)
703 return 0;
704 /* Under the new "aggressive" rule, we resolve mostly trivial
706 * cases that we historically had git-merge-one-file resolve.
707 */
708 if (o->aggressive) {
709 int head_deleted = !head && !df_conflict_head;
710 int remote_deleted = !remote && !df_conflict_remote;
711 const char *path = NULL;
712 if (index)
714 path = index->name;
715 else if (head)
716 path = head->name;
717 else if (remote)
718 path = remote->name;
719 else {
720 for (i = 1; i < o->head_idx; i++) {
721 if (stages[i] && stages[i] != o->df_conflict_entry) {
722 path = stages[i]->name;
723 break;
724 }
725 }
726 }
727 /*
729 * Deleted in both.
730 * Deleted in one and unchanged in the other.
731 */
732 if ((head_deleted && remote_deleted) ||
733 (head_deleted && remote && remote_match) ||
734 (remote_deleted && head && head_match)) {
735 if (index)
736 return deleted_entry(index, index, o);
737 else if (path && !head_deleted)
738 verify_absent(path, "removed", o);
739 return 0;
740 }
741 /*
742 * Added in both, identically.
743 */
744 if (no_anc_exists && head && remote && same(head, remote))
745 return merged_entry(head, index, o);
746 }
748 /* Below are "no merge" cases, which require that the index be
750 * up-to-date to avoid the files getting overwritten with
751 * conflict resolution files.
752 */
753 if (index) {
754 verify_uptodate(index, o);
755 }
756 o->nontrivial_merge = 1;
758 /* #2, #3, #4, #6, #7, #9, #10, #11. */
760 count = 0;
761 if (!head_match || !remote_match) {
762 for (i = 1; i < o->head_idx; i++) {
763 if (stages[i] && stages[i] != o->df_conflict_entry) {
764 keep_entry(stages[i], o);
765 count++;
766 break;
767 }
768 }
769 }
770#if DBRT_DEBUG
771 else {
772 fprintf(stderr, "read-tree: warning #16 detected\n");
773 show_stage_entry(stderr, "head ", stages[head_match]);
774 show_stage_entry(stderr, "remote ", stages[remote_match]);
775 }
776#endif
777 if (head) { count += keep_entry(head, o); }
778 if (remote) { count += keep_entry(remote, o); }
779 return count;
780}
781/*
783 * Two-way merge.
784 *
785 * The rule is to "carry forward" what is in the index without losing
786 * information across a "fast forward", favoring a successful merge
787 * over a merge failure when it makes sense. For details of the
788 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
789 *
790 */
791int twoway_merge(struct cache_entry **src,
792 struct unpack_trees_options *o)
793{
794 struct cache_entry *current = src[0];
795 struct cache_entry *oldtree = src[1];
796 struct cache_entry *newtree = src[2];
797 if (o->merge_size != 2)
799 return error("Cannot do a twoway merge of %d trees",
800 o->merge_size);
801 if (oldtree == o->df_conflict_entry)
803 oldtree = NULL;
804 if (newtree == o->df_conflict_entry)
805 newtree = NULL;
806 if (current) {
808 if ((!oldtree && !newtree) || /* 4 and 5 */
809 (!oldtree && newtree &&
810 same(current, newtree)) || /* 6 and 7 */
811 (oldtree && newtree &&
812 same(oldtree, newtree)) || /* 14 and 15 */
813 (oldtree && newtree &&
814 !same(oldtree, newtree) && /* 18 and 19 */
815 same(current, newtree))) {
816 return keep_entry(current, o);
817 }
818 else if (oldtree && !newtree && same(current, oldtree)) {
819 /* 10 or 11 */
820 return deleted_entry(oldtree, current, o);
821 }
822 else if (oldtree && newtree &&
823 same(current, oldtree) && !same(current, newtree)) {
824 /* 20 or 21 */
825 return merged_entry(newtree, current, o);
826 }
827 else {
828 /* all other failures */
829 if (oldtree)
830 reject_merge(oldtree);
831 if (current)
832 reject_merge(current);
833 if (newtree)
834 reject_merge(newtree);
835 return -1;
836 }
837 }
838 else if (newtree)
839 return merged_entry(newtree, current, o);
840 else
841 return deleted_entry(oldtree, current, o);
842}
843/*
845 * Bind merge.
846 *
847 * Keep the index entries at stage0, collapse stage1 but make sure
848 * stage0 does not have anything there.
849 */
850int bind_merge(struct cache_entry **src,
851 struct unpack_trees_options *o)
852{
853 struct cache_entry *old = src[0];
854 struct cache_entry *a = src[1];
855 if (o->merge_size != 1)
857 return error("Cannot do a bind merge of %d trees\n",
858 o->merge_size);
859 if (a && old)
860 die("Entry '%s' overlaps. Cannot bind.", a->name);
861 if (!a)
862 return keep_entry(old, o);
863 else
864 return merged_entry(a, NULL, o);
865}
866/*
868 * One-way merge.
869 *
870 * The rule is:
871 * - take the stat information from stage0, take the data from stage1
872 */
873int oneway_merge(struct cache_entry **src,
874 struct unpack_trees_options *o)
875{
876 struct cache_entry *old = src[0];
877 struct cache_entry *a = src[1];
878 if (o->merge_size != 1)
880 return error("Cannot do a oneway merge of %d trees",
881 o->merge_size);
882 if (!a)
884 return deleted_entry(old, old, o);
885 if (old && same(old, a)) {
886 if (o->reset) {
887 struct stat st;
888 if (lstat(old->name, &st) ||
889 ce_match_stat(old, &st, 1))
890 old->ce_flags |= htons(CE_UPDATE);
891 }
892 return keep_entry(old, o);
893 }
894 return merged_entry(a, old, o);
895}