Merge branch 'maint'
[git/git.git] / unpack-trees.c
CommitLineData
16da134b 1#include "cache.h"
f8a9d428 2#include "dir.h"
16da134b
JS
3#include "tree.h"
4#include "tree-walk.h"
076b0adc 5#include "cache-tree.h"
16da134b 6#include "unpack-trees.h"
96a02f8f 7#include "progress.h"
16da134b 8
076b0adc
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9#define DBRT_DEBUG 1
10
16da134b
JS
11struct 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};
20
21static 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
076b0adc
JS
28 if (!tree->object.parsed)
29 parse_tree(tree);
30
6fda5e51 31 init_tree_desc(&desc, tree->buffer, tree->size);
16da134b
JS
32
33 while (tree_entry(&desc, &one)) {
34 struct tree_entry_list *entry;
35
36 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
45 *list_p = entry;
46 list_p = &entry->next;
47 }
48 return ret;
49}
50
51static 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}
71
72static int unpack_trees_rec(struct tree_entry_list **posns, int len,
73 const char *base, struct unpack_trees_options *o,
16da134b
JS
74 struct tree_entry_list *df_conflict_list)
75{
76 int baselen = strlen(base);
77 int src_size = len + 1;
f8a9d428
JH
78 int i_stk = i_stk;
79 int retval = 0;
80
81 if (o->dir)
82 i_stk = push_exclude_per_directory(o->dir, base, strlen(base));
83
16da134b
JS
84 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
97 /* Find the first name in the input. */
98
99 first = NULL;
100 cache_name = NULL;
101
102 /* Check the cache */
9a4d8fdc 103 if (o->merge && o->pos < active_nr) {
16da134b
JS
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
9a4d8fdc 121 cache_name = active_cache[o->pos]->name;
16da134b
JS
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
131#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)
f8a9d428 150 goto leave_directory;
16da134b
JS
151
152 pathlen = strlen(first);
153 ce_size = cache_entry_size(baselen + pathlen);
154
155 src = xcalloc(src_size, sizeof(struct cache_entry *));
156
157 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
158
159 if (cache_name && !strcmp(cache_name, first)) {
160 any_files = 1;
9a4d8fdc
JH
161 src[0] = active_cache[o->pos];
162 remove_cache_entry_at(o->pos);
16da134b
JS
163 }
164
165 for (i = 0; i < len; i++) {
166 struct cache_entry *ce;
167
168 if (!posns[i] ||
169 (posns[i] != df_conflict_list &&
170 strcmp(first, posns[i]->name))) {
171 continue;
172 }
173
174 if (posns[i] == df_conflict_list) {
175 src[i + o->merge] = o->df_conflict_entry;
176 continue;
177 }
178
179 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
189 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
198 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
205 any_files = 1;
206
e702496e 207 hashcpy(ce->sha1, posns[i]->sha1);
16da134b
JS
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
216#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
228#if DBRT_DEBUG > 1
229 printf("Added %d entries\n", ret);
230#endif
9a4d8fdc 231 o->pos += ret;
16da134b
JS
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,
9a4d8fdc 247 df_conflict_list)) {
f8a9d428
JH
248 retval = -1;
249 goto leave_directory;
250 }
16da134b
JS
251 free(newbase);
252 }
253 free(subposns);
254 free(src);
255 } while (1);
f8a9d428
JH
256
257 leave_directory:
258 if (o->dir)
259 pop_exclude_per_directory(o->dir, i_stk);
260 return retval;
16da134b
JS
261}
262
263/* 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 */
16a4c617 267static void unlink_entry(char *name, char *last_symlink)
16da134b
JS
268{
269 char *cp, *prev;
270
16a4c617
JH
271 if (has_symlink_leading_path(name, last_symlink))
272 return;
16da134b
JS
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
284 *cp = 0;
285 status = rmdir(name);
286 if (status) {
287 *cp = '/';
288 break;
289 }
290 prev = cp;
291 }
292}
293
16da134b
JS
294static struct checkout state;
295static void check_updates(struct cache_entry **src, int nr,
16a4c617 296 struct unpack_trees_options *o)
16da134b
JS
297{
298 unsigned short mask = htons(CE_UPDATE);
96a02f8f
NP
299 unsigned cnt = 0, total = 0;
300 struct progress progress;
16a4c617 301 char last_symlink[PATH_MAX];
16da134b
JS
302
303 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
55a9137d
NP
310 start_progress_delay(&progress, "Checking %u files out...",
311 "", total, 50, 2);
16da134b
JS
312 cnt = 0;
313 }
314
16a4c617 315 *last_symlink = '\0';
16da134b
JS
316 while (nr--) {
317 struct cache_entry *ce = *src++;
318
96a02f8f
NP
319 if (total)
320 if (!ce->ce_mode || ce->ce_flags & mask)
321 display_progress(&progress, ++cnt);
16da134b
JS
322 if (!ce->ce_mode) {
323 if (o->update)
16a4c617 324 unlink_entry(ce->name, last_symlink);
16da134b
JS
325 continue;
326 }
327 if (ce->ce_flags & mask) {
328 ce->ce_flags &= ~mask;
16a4c617 329 if (o->update) {
16da134b 330 checkout_entry(ce, &state, NULL);
16a4c617
JH
331 *last_symlink = '\0';
332 }
16da134b
JS
333 }
334 }
96a02f8f
NP
335 if (total)
336 stop_progress(&progress);;
16da134b
JS
337}
338
339int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
340{
16da134b
JS
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;
0fb1eaa8 346 static struct cache_entry *dfc;
16da134b
JS
347
348 memset(&df_conflict_list, 0, sizeof(df_conflict_list));
349 df_conflict_list.next = &df_conflict_list;
076b0adc 350 memset(&state, 0, sizeof(state));
16da134b
JS
351 state.base_dir = "";
352 state.force = 1;
353 state.quiet = 1;
354 state.refresh_cache = 1;
355
356 o->merge_size = len;
0fb1eaa8
JH
357
358 if (!dfc)
359 dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
360 o->df_conflict_entry = dfc;
16da134b
JS
361
362 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 : "",
9a4d8fdc 369 o, &df_conflict_list))
16da134b
JS
370 return -1;
371 }
372
373 if (o->trivial_merges_only && o->nontrivial_merge)
374 die("Merge requires file-level merging");
375
376 check_updates(active_cache, active_nr, o);
377 return 0;
378}
076b0adc
JS
379
380/* Here come the merge functions */
381
382static void reject_merge(struct cache_entry *ce)
383{
384 die("Entry '%s' would be overwritten by merge. Cannot merge.",
385 ce->name);
386}
387
388static 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 &&
a89fccd2 395 !hashcmp(a->sha1, b->sha1);
076b0adc
JS
396}
397
398
399/*
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
408 if (o->index_only || o->reset)
409 return;
410
411 if (!lstat(ce->name, &st)) {
412 unsigned changed = ce_match_stat(ce, &st, 1);
413 if (!changed)
414 return;
415 errno = 0;
416 }
076b0adc
JS
417 if (errno == ENOENT)
418 return;
419 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
420}
421
422static void invalidate_ce_path(struct cache_entry *ce)
423{
424 if (ce)
425 cache_tree_invalidate_path(active_cache_tree, ce->name);
426}
427
c8193534
JH
428static int verify_clean_subdirectory(const char *path, const char *action,
429 struct unpack_trees_options *o)
430{
431 /*
432 * we are about to extract "path"; we would not want to lose
433 * anything in the existing directory there.
434 */
435 int namelen;
436 int pos, i;
437 struct dir_struct d;
438 char *pathbuf;
439 int cnt = 0;
440
441 /*
442 * First let's make sure we do not have a local modification
443 * in that directory.
444 */
445 namelen = strlen(path);
446 pos = cache_name_pos(path, namelen);
447 if (0 <= pos)
448 return cnt; /* we have it as nondirectory */
449 pos = -pos - 1;
450 for (i = pos; i < active_nr; i++) {
451 struct cache_entry *ce = active_cache[i];
452 int len = ce_namelen(ce);
453 if (len < namelen ||
454 strncmp(path, ce->name, namelen) ||
455 ce->name[namelen] != '/')
456 break;
457 /*
458 * ce->name is an entry in the subdirectory.
459 */
460 if (!ce_stage(ce)) {
461 verify_uptodate(ce, o);
462 ce->ce_mode = 0;
463 }
464 cnt++;
465 }
466
467 /*
468 * Then we need to make sure that we do not lose a locally
469 * present file that is not ignored.
470 */
471 pathbuf = xmalloc(namelen + 2);
472 memcpy(pathbuf, path, namelen);
473 strcpy(pathbuf+namelen, "/");
474
475 memset(&d, 0, sizeof(d));
476 if (o->dir)
477 d.exclude_per_dir = o->dir->exclude_per_dir;
478 i = read_directory(&d, path, pathbuf, namelen+1, NULL);
479 if (i)
480 die("Updating '%s' would lose untracked files in it",
481 path);
482 free(pathbuf);
483 return cnt;
484}
485
076b0adc
JS
486/*
487 * We do not want to remove or overwrite a working tree file that
f8a9d428 488 * is not tracked, unless it is ignored.
076b0adc
JS
489 */
490static void verify_absent(const char *path, const char *action,
491 struct unpack_trees_options *o)
492{
493 struct stat st;
494
495 if (o->index_only || o->reset || !o->update)
496 return;
c8193534 497
ec0603e1
JH
498 if (has_symlink_leading_path(path, NULL))
499 return;
500
c8193534
JH
501 if (!lstat(path, &st)) {
502 int cnt;
503
504 if (o->dir && excluded(o->dir, path))
505 /*
506 * path is explicitly excluded, so it is Ok to
507 * overwrite it.
508 */
509 return;
510 if (S_ISDIR(st.st_mode)) {
511 /*
512 * We are checking out path "foo" and
513 * found "foo/." in the working tree.
514 * This is tricky -- if we have modified
515 * files that are in "foo/" we would lose
516 * it.
517 */
518 cnt = verify_clean_subdirectory(path, action, o);
519
520 /*
521 * If this removed entries from the index,
522 * what that means is:
523 *
524 * (1) the caller unpack_trees_rec() saw path/foo
525 * in the index, and it has not removed it because
526 * it thinks it is handling 'path' as blob with
527 * D/F conflict;
528 * (2) we will return "ok, we placed a merged entry
529 * in the index" which would cause o->pos to be
530 * incremented by one;
531 * (3) however, original o->pos now has 'path/foo'
532 * marked with "to be removed".
533 *
534 * We need to increment it by the number of
535 * deleted entries here.
536 */
537 o->pos += cnt;
538 return;
539 }
540
541 /*
542 * The previous round may already have decided to
543 * delete this path, which is in a subdirectory that
544 * is being replaced with a blob.
545 */
546 cnt = cache_name_pos(path, strlen(path));
547 if (0 <= cnt) {
548 struct cache_entry *ce = active_cache[cnt];
549 if (!ce_stage(ce) && !ce->ce_mode)
550 return;
551 }
552
076b0adc
JS
553 die("Untracked working tree file '%s' "
554 "would be %s by merge.", path, action);
c8193534 555 }
076b0adc
JS
556}
557
558static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
559 struct unpack_trees_options *o)
560{
561 merge->ce_flags |= htons(CE_UPDATE);
562 if (old) {
563 /*
564 * See if we can re-use the old CE directly?
565 * That way we get the uptodate stat info.
566 *
567 * This also removes the UPDATE flag on
568 * a match.
569 */
570 if (same(old, merge)) {
571 *merge = *old;
572 } else {
573 verify_uptodate(old, o);
574 invalidate_ce_path(old);
575 }
576 }
577 else {
578 verify_absent(merge->name, "overwritten", o);
579 invalidate_ce_path(merge);
580 }
581
582 merge->ce_flags &= ~htons(CE_STAGEMASK);
583 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
584 return 1;
585}
586
587static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
588 struct unpack_trees_options *o)
589{
590 if (old)
591 verify_uptodate(old, o);
592 else
593 verify_absent(ce->name, "removed", o);
594 ce->ce_mode = 0;
595 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
596 invalidate_ce_path(ce);
597 return 1;
598}
599
7f7932ab 600static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
076b0adc
JS
601{
602 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
603 return 1;
604}
605
606#if DBRT_DEBUG
607static void show_stage_entry(FILE *o,
608 const char *label, const struct cache_entry *ce)
609{
610 if (!ce)
611 fprintf(o, "%s (missing)\n", label);
612 else
613 fprintf(o, "%s%06o %s %d\t%s\n",
614 label,
615 ntohl(ce->ce_mode),
616 sha1_to_hex(ce->sha1),
617 ce_stage(ce),
618 ce->name);
619}
620#endif
621
622int threeway_merge(struct cache_entry **stages,
623 struct unpack_trees_options *o)
624{
625 struct cache_entry *index;
626 struct cache_entry *head;
627 struct cache_entry *remote = stages[o->head_idx + 1];
628 int count;
629 int head_match = 0;
630 int remote_match = 0;
076b0adc
JS
631
632 int df_conflict_head = 0;
633 int df_conflict_remote = 0;
634
635 int any_anc_missing = 0;
636 int no_anc_exists = 1;
637 int i;
638
639 for (i = 1; i < o->head_idx; i++) {
4c4caafc 640 if (!stages[i] || stages[i] == o->df_conflict_entry)
076b0adc 641 any_anc_missing = 1;
4c4caafc 642 else
076b0adc 643 no_anc_exists = 0;
076b0adc
JS
644 }
645
646 index = stages[0];
647 head = stages[o->head_idx];
648
649 if (head == o->df_conflict_entry) {
650 df_conflict_head = 1;
651 head = NULL;
652 }
653
654 if (remote == o->df_conflict_entry) {
655 df_conflict_remote = 1;
656 remote = NULL;
657 }
658
076b0adc
JS
659 /* First, if there's a #16 situation, note that to prevent #13
660 * and #14.
661 */
662 if (!same(remote, head)) {
663 for (i = 1; i < o->head_idx; i++) {
664 if (same(stages[i], head)) {
665 head_match = i;
666 }
667 if (same(stages[i], remote)) {
668 remote_match = i;
669 }
670 }
671 }
672
673 /* We start with cases where the index is allowed to match
674 * something other than the head: #14(ALT) and #2ALT, where it
675 * is permitted to match the result instead.
676 */
677 /* #14, #14ALT, #2ALT */
678 if (remote && !df_conflict_head && head_match && !remote_match) {
679 if (index && !same(index, remote) && !same(index, head))
680 reject_merge(index);
681 return merged_entry(remote, index, o);
682 }
683 /*
684 * If we have an entry in the index cache, then we want to
685 * make sure that it matches head.
686 */
687 if (index && !same(index, head)) {
688 reject_merge(index);
689 }
690
691 if (head) {
692 /* #5ALT, #15 */
693 if (same(head, remote))
694 return merged_entry(head, index, o);
695 /* #13, #3ALT */
696 if (!df_conflict_remote && remote_match && !head_match)
697 return merged_entry(head, index, o);
698 }
699
700 /* #1 */
701 if (!head && !remote && any_anc_missing)
702 return 0;
703
704 /* Under the new "aggressive" rule, we resolve mostly trivial
705 * cases that we historically had git-merge-one-file resolve.
706 */
707 if (o->aggressive) {
708 int head_deleted = !head && !df_conflict_head;
709 int remote_deleted = !remote && !df_conflict_remote;
4c4caafc
JH
710 const char *path = NULL;
711
712 if (index)
713 path = index->name;
714 else if (head)
715 path = head->name;
716 else if (remote)
717 path = remote->name;
718 else {
719 for (i = 1; i < o->head_idx; i++) {
720 if (stages[i] && stages[i] != o->df_conflict_entry) {
721 path = stages[i]->name;
722 break;
723 }
724 }
725 }
726
076b0adc
JS
727 /*
728 * Deleted in both.
729 * Deleted in one and unchanged in the other.
730 */
731 if ((head_deleted && remote_deleted) ||
732 (head_deleted && remote && remote_match) ||
733 (remote_deleted && head && head_match)) {
734 if (index)
735 return deleted_entry(index, index, o);
ed93b449 736 else if (path && !head_deleted)
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737 verify_absent(path, "removed", o);
738 return 0;
739 }
740 /*
741 * Added in both, identically.
742 */
743 if (no_anc_exists && head && remote && same(head, remote))
744 return merged_entry(head, index, o);
745
746 }
747
748 /* Below are "no merge" cases, which require that the index be
749 * up-to-date to avoid the files getting overwritten with
750 * conflict resolution files.
751 */
752 if (index) {
753 verify_uptodate(index, o);
754 }
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755
756 o->nontrivial_merge = 1;
757
ea4b52a8 758 /* #2, #3, #4, #6, #7, #9, #10, #11. */
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759 count = 0;
760 if (!head_match || !remote_match) {
761 for (i = 1; i < o->head_idx; i++) {
4c4caafc 762 if (stages[i] && stages[i] != o->df_conflict_entry) {
7f7932ab 763 keep_entry(stages[i], o);
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764 count++;
765 break;
766 }
767 }
768 }
769#if DBRT_DEBUG
770 else {
771 fprintf(stderr, "read-tree: warning #16 detected\n");
772 show_stage_entry(stderr, "head ", stages[head_match]);
773 show_stage_entry(stderr, "remote ", stages[remote_match]);
774 }
775#endif
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776 if (head) { count += keep_entry(head, o); }
777 if (remote) { count += keep_entry(remote, o); }
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778 return count;
779}
780
781/*
782 * Two-way merge.
783 *
784 * The rule is to "carry forward" what is in the index without losing
785 * information across a "fast forward", favoring a successful merge
786 * over a merge failure when it makes sense. For details of the
787 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
788 *
789 */
790int twoway_merge(struct cache_entry **src,
791 struct unpack_trees_options *o)
792{
793 struct cache_entry *current = src[0];
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794 struct cache_entry *oldtree = src[1];
795 struct cache_entry *newtree = src[2];
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796
797 if (o->merge_size != 2)
798 return error("Cannot do a twoway merge of %d trees",
799 o->merge_size);
800
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801 if (oldtree == o->df_conflict_entry)
802 oldtree = NULL;
803 if (newtree == o->df_conflict_entry)
804 newtree = NULL;
805
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806 if (current) {
807 if ((!oldtree && !newtree) || /* 4 and 5 */
808 (!oldtree && newtree &&
809 same(current, newtree)) || /* 6 and 7 */
810 (oldtree && newtree &&
811 same(oldtree, newtree)) || /* 14 and 15 */
812 (oldtree && newtree &&
b8ba1535 813 !same(oldtree, newtree) && /* 18 and 19 */
076b0adc 814 same(current, newtree))) {
7f7932ab 815 return keep_entry(current, o);
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816 }
817 else if (oldtree && !newtree && same(current, oldtree)) {
818 /* 10 or 11 */
819 return deleted_entry(oldtree, current, o);
820 }
821 else if (oldtree && newtree &&
822 same(current, oldtree) && !same(current, newtree)) {
823 /* 20 or 21 */
824 return merged_entry(newtree, current, o);
825 }
826 else {
827 /* all other failures */
828 if (oldtree)
829 reject_merge(oldtree);
830 if (current)
831 reject_merge(current);
832 if (newtree)
833 reject_merge(newtree);
834 return -1;
835 }
836 }
837 else if (newtree)
838 return merged_entry(newtree, current, o);
839 else
840 return deleted_entry(oldtree, current, o);
841}
842
843/*
844 * Bind merge.
845 *
846 * Keep the index entries at stage0, collapse stage1 but make sure
847 * stage0 does not have anything there.
848 */
849int bind_merge(struct cache_entry **src,
850 struct unpack_trees_options *o)
851{
852 struct cache_entry *old = src[0];
853 struct cache_entry *a = src[1];
854
855 if (o->merge_size != 1)
856 return error("Cannot do a bind merge of %d trees\n",
857 o->merge_size);
858 if (a && old)
859 die("Entry '%s' overlaps. Cannot bind.", a->name);
860 if (!a)
7f7932ab 861 return keep_entry(old, o);
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862 else
863 return merged_entry(a, NULL, o);
864}
865
866/*
867 * One-way merge.
868 *
869 * The rule is:
870 * - take the stat information from stage0, take the data from stage1
871 */
872int oneway_merge(struct cache_entry **src,
873 struct unpack_trees_options *o)
874{
875 struct cache_entry *old = src[0];
876 struct cache_entry *a = src[1];
877
878 if (o->merge_size != 1)
879 return error("Cannot do a oneway merge of %d trees",
880 o->merge_size);
881
882 if (!a)
883 return deleted_entry(old, old, o);
884 if (old && same(old, a)) {
885 if (o->reset) {
886 struct stat st;
887 if (lstat(old->name, &st) ||
888 ce_match_stat(old, &st, 1))
889 old->ce_flags |= htons(CE_UPDATE);
890 }
7f7932ab 891 return keep_entry(old, o);
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892 }
893 return merged_entry(a, old, o);
894}