1/*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
6#define DBRT_DEBUG 1
7#include "cache.h"
9#include "object.h"
11#include "tree.h"
12#include "cache-tree.h"
13#include <sys/time.h>
14#include <signal.h>
15static int merge = 0;
17static int update = 0;
18static int index_only = 0;
19static int nontrivial_merge = 0;
20static int trivial_merges_only = 0;
21static int aggressive = 0;
22static int verbose_update = 0;
23static volatile int progress_update = 0;
24static const char *prefix = NULL;
25static int head_idx = -1;
27static int merge_size = 0;
28static struct object_list *trees = NULL;
30static struct cache_entry df_conflict_entry = {
32};
33static struct tree_entry_list df_conflict_list = {
35 .name = NULL,
36 .next = &df_conflict_list
37};
38typedef int (*merge_fn_t)(struct cache_entry **src);
40static int entcmp(char *name1, int dir1, char *name2, int dir2)
42{
43 int len1 = strlen(name1);
44 int len2 = strlen(name2);
45 int len = len1 < len2 ? len1 : len2;
46 int ret = memcmp(name1, name2, len);
47 unsigned char c1, c2;
48 if (ret)
49 return ret;
50 c1 = name1[len];
51 c2 = name2[len];
52 if (!c1 && dir1)
53 c1 = '/';
54 if (!c2 && dir2)
55 c2 = '/';
56 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
57 if (c1 && c2 && !ret)
58 ret = len1 - len2;
59 return ret;
60}
61static int unpack_trees_rec(struct tree_entry_list **posns, int len,
63 const char *base, merge_fn_t fn, int *indpos)
64{
65 int baselen = strlen(base);
66 int src_size = len + 1;
67 do {
68 int i;
69 char *first;
70 int firstdir = 0;
71 int pathlen;
72 unsigned ce_size;
73 struct tree_entry_list **subposns;
74 struct cache_entry **src;
75 int any_files = 0;
76 int any_dirs = 0;
77 char *cache_name;
78 int ce_stage;
79 /* Find the first name in the input. */
81 first = NULL;
83 cache_name = NULL;
84 /* Check the cache */
86 if (merge && *indpos < active_nr) {
87 /* This is a bit tricky: */
88 /* If the index has a subdirectory (with
89 * contents) as the first name, it'll get a
90 * filename like "foo/bar". But that's after
91 * "foo", so the entry in trees will get
92 * handled first, at which point we'll go into
93 * "foo", and deal with "bar" from the index,
94 * because the base will be "foo/". The only
95 * way we can actually have "foo/bar" first of
96 * all the things is if the trees don't
97 * contain "foo" at all, in which case we'll
98 * handle "foo/bar" without going into the
99 * directory, but that's fine (and will return
100 * an error anyway, with the added unknown
101 * file case.
102 */
103 cache_name = active_cache[*indpos]->name;
105 if (strlen(cache_name) > baselen &&
106 !memcmp(cache_name, base, baselen)) {
107 cache_name += baselen;
108 first = cache_name;
109 } else {
110 cache_name = NULL;
111 }
112 }
113#if DBRT_DEBUG > 1
115 if (first)
116 printf("index %s\n", first);
117#endif
118 for (i = 0; i < len; i++) {
119 if (!posns[i] || posns[i] == &df_conflict_list)
120 continue;
121#if DBRT_DEBUG > 1
122 printf("%d %s\n", i + 1, posns[i]->name);
123#endif
124 if (!first || entcmp(first, firstdir,
125 posns[i]->name,
126 posns[i]->directory) > 0) {
127 first = posns[i]->name;
128 firstdir = posns[i]->directory;
129 }
130 }
131 /* No name means we're done */
132 if (!first)
133 return 0;
134 pathlen = strlen(first);
136 ce_size = cache_entry_size(baselen + pathlen);
137 src = xcalloc(src_size, sizeof(struct cache_entry *));
139 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
141 if (cache_name && !strcmp(cache_name, first)) {
143 any_files = 1;
144 src[0] = active_cache[*indpos];
145 remove_cache_entry_at(*indpos);
146 }
147 for (i = 0; i < len; i++) {
149 struct cache_entry *ce;
150 if (!posns[i] ||
152 (posns[i] != &df_conflict_list &&
153 strcmp(first, posns[i]->name))) {
154 continue;
155 }
156 if (posns[i] == &df_conflict_list) {
158 src[i + merge] = &df_conflict_entry;
159 continue;
160 }
161 if (posns[i]->directory) {
163 any_dirs = 1;
164 parse_tree(posns[i]->item.tree);
165 subposns[i] = posns[i]->item.tree->entries;
166 posns[i] = posns[i]->next;
167 src[i + merge] = &df_conflict_entry;
168 continue;
169 }
170 if (!merge)
172 ce_stage = 0;
173 else if (i + 1 < head_idx)
174 ce_stage = 1;
175 else if (i + 1 > head_idx)
176 ce_stage = 3;
177 else
178 ce_stage = 2;
179 ce = xcalloc(1, ce_size);
181 ce->ce_mode = create_ce_mode(posns[i]->mode);
182 ce->ce_flags = create_ce_flags(baselen + pathlen,
183 ce_stage);
184 memcpy(ce->name, base, baselen);
185 memcpy(ce->name + baselen, first, pathlen + 1);
186 any_files = 1;
188 memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
190 src[i + merge] = ce;
191 subposns[i] = &df_conflict_list;
192 posns[i] = posns[i]->next;
193 }
194 if (any_files) {
195 if (merge) {
196 int ret;
197#if DBRT_DEBUG > 1
199 printf("%s:\n", first);
200 for (i = 0; i < src_size; i++) {
201 printf(" %d ", i);
202 if (src[i])
203 printf("%s\n", sha1_to_hex(src[i]->sha1));
204 else
205 printf("\n");
206 }
207#endif
208 ret = fn(src);
209
210#if DBRT_DEBUG > 1
211 printf("Added %d entries\n", ret);
212#endif
213 *indpos += ret;
214 } else {
215 for (i = 0; i < src_size; i++) {
216 if (src[i]) {
217 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
218 }
219 }
220 }
221 }
222 if (any_dirs) {
223 char *newbase = xmalloc(baselen + 2 + pathlen);
224 memcpy(newbase, base, baselen);
225 memcpy(newbase + baselen, first, pathlen);
226 newbase[baselen + pathlen] = '/';
227 newbase[baselen + pathlen + 1] = '\0';
228 if (unpack_trees_rec(subposns, len, newbase, fn,
229 indpos))
230 return -1;
231 free(newbase);
232 }
233 free(subposns);
234 free(src);
235 } while (1);
236}
237static void reject_merge(struct cache_entry *ce)
239{
240 die("Entry '%s' would be overwritten by merge. Cannot merge.",
241 ce->name);
242}
243/* Unlink the last component and attempt to remove leading
245 * directories, in case this unlink is the removal of the
246 * last entry in the directory -- empty directories are removed.
247 */
248static void unlink_entry(char *name)
249{
250 char *cp, *prev;
251 if (unlink(name))
253 return;
254 prev = NULL;
255 while (1) {
256 int status;
257 cp = strrchr(name, '/');
258 if (prev)
259 *prev = '/';
260 if (!cp)
261 break;
262 *cp = 0;
264 status = rmdir(name);
265 if (status) {
266 *cp = '/';
267 break;
268 }
269 prev = cp;
270 }
271}
272static void progress_interval(int signum)
274{
275 progress_update = 1;
276}
277static void setup_progress_signal(void)
279{
280 struct sigaction sa;
281 struct itimerval v;
282 memset(&sa, 0, sizeof(sa));
284 sa.sa_handler = progress_interval;
285 sigemptyset(&sa.sa_mask);
286 sa.sa_flags = SA_RESTART;
287 sigaction(SIGALRM, &sa, NULL);
288 v.it_interval.tv_sec = 1;
290 v.it_interval.tv_usec = 0;
291 v.it_value = v.it_interval;
292 setitimer(ITIMER_REAL, &v, NULL);
293}
294static void check_updates(struct cache_entry **src, int nr)
296{
297 static struct checkout state = {
298 .base_dir = "",
299 .force = 1,
300 .quiet = 1,
301 .refresh_cache = 1,
302 };
303 unsigned short mask = htons(CE_UPDATE);
304 unsigned last_percent = 200, cnt = 0, total = 0;
305 if (update && verbose_update) {
307 for (total = cnt = 0; cnt < nr; cnt++) {
308 struct cache_entry *ce = src[cnt];
309 if (!ce->ce_mode || ce->ce_flags & mask)
310 total++;
311 }
312 /* Don't bother doing this for very small updates */
314 if (total < 250)
315 total = 0;
316 if (total) {
318 fprintf(stderr, "Checking files out...\n");
319 setup_progress_signal();
320 progress_update = 1;
321 }
322 cnt = 0;
323 }
324 while (nr--) {
326 struct cache_entry *ce = *src++;
327 if (total) {
329 if (!ce->ce_mode || ce->ce_flags & mask) {
330 unsigned percent;
331 cnt++;
332 percent = (cnt * 100) / total;
333 if (percent != last_percent ||
334 progress_update) {
335 fprintf(stderr, "%4u%% (%u/%u) done\r",
336 percent, cnt, total);
337 last_percent = percent;
338 }
339 }
340 }
341 if (!ce->ce_mode) {
342 if (update)
343 unlink_entry(ce->name);
344 continue;
345 }
346 if (ce->ce_flags & mask) {
347 ce->ce_flags &= ~mask;
348 if (update)
349 checkout_entry(ce, &state, NULL);
350 }
351 }
352 if (total) {
353 signal(SIGALRM, SIG_IGN);
354 fputc('\n', stderr);
355 }
356}
357static int unpack_trees(merge_fn_t fn)
359{
360 int indpos = 0;
361 unsigned len = object_list_length(trees);
362 struct tree_entry_list **posns;
363 int i;
364 struct object_list *posn = trees;
365 merge_size = len;
366 if (len) {
368 posns = xmalloc(len * sizeof(struct tree_entry_list *));
369 for (i = 0; i < len; i++) {
370 posns[i] = ((struct tree *) posn->item)->entries;
371 posn = posn->next;
372 }
373 if (unpack_trees_rec(posns, len, prefix ? prefix : "",
374 fn, &indpos))
375 return -1;
376 }
377 if (trivial_merges_only && nontrivial_merge)
379 die("Merge requires file-level merging");
380 check_updates(active_cache, active_nr);
382 return 0;
383}
384static int list_tree(unsigned char *sha1)
386{
387 struct tree *tree = parse_tree_indirect(sha1);
388 if (!tree)
389 return -1;
390 object_list_append(&tree->object, &trees);
391 return 0;
392}
393static int same(struct cache_entry *a, struct cache_entry *b)
395{
396 if (!!a != !!b)
397 return 0;
398 if (!a && !b)
399 return 1;
400 return a->ce_mode == b->ce_mode &&
401 !memcmp(a->sha1, b->sha1, 20);
402}
403/*
406 * When a CE gets turned into an unmerged entry, we
407 * want it to be up-to-date
408 */
409static void verify_uptodate(struct cache_entry *ce)
410{
411 struct stat st;
412 if (index_only)
414 return;
415 if (!lstat(ce->name, &st)) {
417 unsigned changed = ce_match_stat(ce, &st, 1);
418 if (!changed)
419 return;
420 errno = 0;
421 }
422 if (errno == ENOENT)
423 return;
424 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
425}
426static void invalidate_ce_path(struct cache_entry *ce)
428{
429 if (ce)
430 cache_tree_invalidate_path(active_cache_tree, ce->name);
431}
432static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
434{
435 merge->ce_flags |= htons(CE_UPDATE);
436 if (old) {
437 /*
438 * See if we can re-use the old CE directly?
439 * That way we get the uptodate stat info.
440 *
441 * This also removes the UPDATE flag on
442 * a match.
443 */
444 if (same(old, merge)) {
445 *merge = *old;
446 } else {
447 verify_uptodate(old);
448 invalidate_ce_path(old);
449 }
450 }
451 merge->ce_flags &= ~htons(CE_STAGEMASK);
452 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
453 return 1;
454}
455static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
457{
458 if (old)
459 verify_uptodate(old);
460 ce->ce_mode = 0;
461 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
462 invalidate_ce_path(ce);
463 return 1;
464}
465static int keep_entry(struct cache_entry *ce)
467{
468 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
469 return 1;
470}
471#if DBRT_DEBUG
473static void show_stage_entry(FILE *o,
474 const char *label, const struct cache_entry *ce)
475{
476 if (!ce)
477 fprintf(o, "%s (missing)\n", label);
478 else
479 fprintf(o, "%s%06o %s %d\t%s\n",
480 label,
481 ntohl(ce->ce_mode),
482 sha1_to_hex(ce->sha1),
483 ce_stage(ce),
484 ce->name);
485}
486#endif
487static int threeway_merge(struct cache_entry **stages)
489{
490 struct cache_entry *index;
491 struct cache_entry *head;
492 struct cache_entry *remote = stages[head_idx + 1];
493 int count;
494 int head_match = 0;
495 int remote_match = 0;
496 int df_conflict_head = 0;
498 int df_conflict_remote = 0;
499 int any_anc_missing = 0;
501 int no_anc_exists = 1;
502 int i;
503 for (i = 1; i < head_idx; i++) {
505 if (!stages[i])
506 any_anc_missing = 1;
507 else
508 no_anc_exists = 0;
509 }
510 index = stages[0];
512 head = stages[head_idx];
513 if (head == &df_conflict_entry) {
515 df_conflict_head = 1;
516 head = NULL;
517 }
518 if (remote == &df_conflict_entry) {
520 df_conflict_remote = 1;
521 remote = NULL;
522 }
523 /* First, if there's a #16 situation, note that to prevent #13
525 * and #14.
526 */
527 if (!same(remote, head)) {
528 for (i = 1; i < head_idx; i++) {
529 if (same(stages[i], head)) {
530 head_match = i;
531 }
532 if (same(stages[i], remote)) {
533 remote_match = i;
534 }
535 }
536 }
537 /* We start with cases where the index is allowed to match
539 * something other than the head: #14(ALT) and #2ALT, where it
540 * is permitted to match the result instead.
541 */
542 /* #14, #14ALT, #2ALT */
543 if (remote && !df_conflict_head && head_match && !remote_match) {
544 if (index && !same(index, remote) && !same(index, head))
545 reject_merge(index);
546 return merged_entry(remote, index);
547 }
548 /*
549 * If we have an entry in the index cache, then we want to
550 * make sure that it matches head.
551 */
552 if (index && !same(index, head)) {
553 reject_merge(index);
554 }
555 if (head) {
557 /* #5ALT, #15 */
558 if (same(head, remote))
559 return merged_entry(head, index);
560 /* #13, #3ALT */
561 if (!df_conflict_remote && remote_match && !head_match)
562 return merged_entry(head, index);
563 }
564 /* #1 */
566 if (!head && !remote && any_anc_missing)
567 return 0;
568 /* Under the new "aggressive" rule, we resolve mostly trivial
570 * cases that we historically had git-merge-one-file resolve.
571 */
572 if (aggressive) {
573 int head_deleted = !head && !df_conflict_head;
574 int remote_deleted = !remote && !df_conflict_remote;
575 /*
576 * Deleted in both.
577 * Deleted in one and unchanged in the other.
578 */
579 if ((head_deleted && remote_deleted) ||
580 (head_deleted && remote && remote_match) ||
581 (remote_deleted && head && head_match)) {
582 if (index)
583 return deleted_entry(index, index);
584 return 0;
585 }
586 /*
587 * Added in both, identically.
588 */
589 if (no_anc_exists && head && remote && same(head, remote))
590 return merged_entry(head, index);
591 }
593 /* Below are "no merge" cases, which require that the index be
595 * up-to-date to avoid the files getting overwritten with
596 * conflict resolution files.
597 */
598 if (index) {
599 verify_uptodate(index);
600 }
601 nontrivial_merge = 1;
603 /* #2, #3, #4, #6, #7, #9, #11. */
605 count = 0;
606 if (!head_match || !remote_match) {
607 for (i = 1; i < head_idx; i++) {
608 if (stages[i]) {
609 keep_entry(stages[i]);
610 count++;
611 break;
612 }
613 }
614 }
615#if DBRT_DEBUG
616 else {
617 fprintf(stderr, "read-tree: warning #16 detected\n");
618 show_stage_entry(stderr, "head ", stages[head_match]);
619 show_stage_entry(stderr, "remote ", stages[remote_match]);
620 }
621#endif
622 if (head) { count += keep_entry(head); }
623 if (remote) { count += keep_entry(remote); }
624 return count;
625}
626/*
628 * Two-way merge.
629 *
630 * The rule is to "carry forward" what is in the index without losing
631 * information across a "fast forward", favoring a successful merge
632 * over a merge failure when it makes sense. For details of the
633 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
634 *
635 */
636static int twoway_merge(struct cache_entry **src)
637{
638 struct cache_entry *current = src[0];
639 struct cache_entry *oldtree = src[1], *newtree = src[2];
640 if (merge_size != 2)
642 return error("Cannot do a twoway merge of %d trees",
643 merge_size);
644 if (current) {
646 if ((!oldtree && !newtree) || /* 4 and 5 */
647 (!oldtree && newtree &&
648 same(current, newtree)) || /* 6 and 7 */
649 (oldtree && newtree &&
650 same(oldtree, newtree)) || /* 14 and 15 */
651 (oldtree && newtree &&
652 !same(oldtree, newtree) && /* 18 and 19*/
653 same(current, newtree))) {
654 return keep_entry(current);
655 }
656 else if (oldtree && !newtree && same(current, oldtree)) {
657 /* 10 or 11 */
658 return deleted_entry(oldtree, current);
659 }
660 else if (oldtree && newtree &&
661 same(current, oldtree) && !same(current, newtree)) {
662 /* 20 or 21 */
663 return merged_entry(newtree, current);
664 }
665 else {
666 /* all other failures */
667 if (oldtree)
668 reject_merge(oldtree);
669 if (current)
670 reject_merge(current);
671 if (newtree)
672 reject_merge(newtree);
673 return -1;
674 }
675 }
676 else if (newtree)
677 return merged_entry(newtree, current);
678 else
679 return deleted_entry(oldtree, current);
680}
681/*
683 * Bind merge.
684 *
685 * Keep the index entries at stage0, collapse stage1 but make sure
686 * stage0 does not have anything there.
687 */
688static int bind_merge(struct cache_entry **src)
689{
690 struct cache_entry *old = src[0];
691 struct cache_entry *a = src[1];
692 if (merge_size != 1)
694 return error("Cannot do a bind merge of %d trees\n",
695 merge_size);
696 if (a && old)
697 die("Entry '%s' overlaps. Cannot bind.", a->name);
698 if (!a)
699 return keep_entry(old);
700 else
701 return merged_entry(a, NULL);
702}
703/*
705 * One-way merge.
706 *
707 * The rule is:
708 * - take the stat information from stage0, take the data from stage1
709 */
710static int oneway_merge(struct cache_entry **src)
711{
712 struct cache_entry *old = src[0];
713 struct cache_entry *a = src[1];
714 if (merge_size != 1)
716 return error("Cannot do a oneway merge of %d trees",
717 merge_size);
718 if (!a) {
720 invalidate_ce_path(old);
721 return 0;
722 }
723 if (old && same(old, a)) {
724 return keep_entry(old);
725 }
726 return merged_entry(a, NULL);
727}
728static int read_cache_unmerged(void)
730{
731 int i, deleted;
732 struct cache_entry **dst;
733 read_cache();
735 dst = active_cache;
736 deleted = 0;
737 for (i = 0; i < active_nr; i++) {
738 struct cache_entry *ce = active_cache[i];
739 if (ce_stage(ce)) {
740 deleted++;
741 invalidate_ce_path(ce);
742 continue;
743 }
744 if (deleted)
745 *dst = ce;
746 dst++;
747 }
748 active_nr -= deleted;
749 return deleted;
750}
751static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
753{
754 struct tree_entry_list *ent;
755 int cnt;
756
757 memcpy(it->sha1, tree->object.sha1, 20);
758 for (cnt = 0, ent = tree->entries; ent; ent = ent->next) {
759 if (!ent->directory)
760 cnt++;
761 else {
762 struct cache_tree_sub *sub;
763 struct tree *subtree = (struct tree *)ent->item.tree;
764 if (!subtree->object.parsed)
765 parse_tree(subtree);
766 sub = cache_tree_sub(it, ent->name);
767 sub->cache_tree = cache_tree();
768 prime_cache_tree_rec(sub->cache_tree, subtree);
769 cnt += sub->cache_tree->entry_count;
770 }
771 }
772 it->entry_count = cnt;
773}
774static void prime_cache_tree(void)
776{
777 struct tree *tree = (struct tree *)trees->item;
778 if (!tree)
779 return;
780 active_cache_tree = cache_tree();
781 prime_cache_tree_rec(active_cache_tree, tree);
782}
784static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] <sha1> [<sha2> [<sha3>]])";
786static struct cache_file cache_file;
788int main(int argc, char **argv)
790{
791 int i, newfd, reset, stage = 0;
792 unsigned char sha1[20];
793 merge_fn_t fn = NULL;
794 setup_git_directory();
796 git_config(git_default_config);
797 newfd = hold_index_file_for_update(&cache_file, get_index_file());
799 if (newfd < 0)
800 die("unable to create new cachefile");
801 git_config(git_default_config);
803 merge = 0;
805 reset = 0;
806 for (i = 1; i < argc; i++) {
807 const char *arg = argv[i];
808 /* "-u" means "update", meaning that a merge will update
810 * the working tree.
811 */
812 if (!strcmp(arg, "-u")) {
813 update = 1;
814 continue;
815 }
816 if (!strcmp(arg, "-v")) {
818 verbose_update = 1;
819 continue;
820 }
821 /* "-i" means "index only", meaning that a merge will
823 * not even look at the working tree.
824 */
825 if (!strcmp(arg, "-i")) {
826 index_only = 1;
827 continue;
828 }
829 /* "--prefix=<subdirectory>/" means keep the current index
831 * entries and put the entries from the tree under the
832 * given subdirectory.
833 */
834 if (!strncmp(arg, "--prefix=", 9)) {
835 if (stage || merge || prefix)
836 usage(read_tree_usage);
837 prefix = arg + 9;
838 merge = 1;
839 stage = 1;
840 if (read_cache_unmerged())
841 die("you need to resolve your current index first");
842 continue;
843 }
844 /* This differs from "-m" in that we'll silently ignore unmerged entries */
846 if (!strcmp(arg, "--reset")) {
847 if (stage || merge || prefix)
848 usage(read_tree_usage);
849 reset = 1;
850 merge = 1;
851 stage = 1;
852 read_cache_unmerged();
853 continue;
854 }
855 if (!strcmp(arg, "--trivial")) {
857 trivial_merges_only = 1;
858 continue;
859 }
860 if (!strcmp(arg, "--aggressive")) {
862 aggressive = 1;
863 continue;
864 }
865 /* "-m" stands for "merge", meaning we start in stage 1 */
867 if (!strcmp(arg, "-m")) {
868 if (stage || merge || prefix)
869 usage(read_tree_usage);
870 if (read_cache_unmerged())
871 die("you need to resolve your current index first");
872 stage = 1;
873 merge = 1;
874 continue;
875 }
876 /* using -u and -i at the same time makes no sense */
878 if (1 < index_only + update)
879 usage(read_tree_usage);
880 if (get_sha1(arg, sha1) < 0)
882 usage(read_tree_usage);
883 if (list_tree(sha1) < 0)
884 die("failed to unpack tree object %s", arg);
885 stage++;
886 }
887 if ((update||index_only) && !merge)
888 usage(read_tree_usage);
889 if (prefix) {
891 int pfxlen = strlen(prefix);
892 int pos;
893 if (prefix[pfxlen-1] != '/')
894 die("prefix must end with /");
895 if (stage != 2)
896 die("binding merge takes only one tree");
897 pos = cache_name_pos(prefix, pfxlen);
898 if (0 <= pos)
899 die("corrupt index file");
900 pos = -pos-1;
901 if (pos < active_nr &&
902 !strncmp(active_cache[pos]->name, prefix, pfxlen))
903 die("subdirectory '%s' already exists.", prefix);
904 pos = cache_name_pos(prefix, pfxlen-1);
905 if (0 <= pos)
906 die("file '%.*s' already exists.", pfxlen-1, prefix);
907 }
908 if (merge) {
910 if (stage < 2)
911 die("just how do you expect me to merge %d trees?", stage-1);
912 switch (stage - 1) {
913 case 1:
914 fn = prefix ? bind_merge : oneway_merge;
915 break;
916 case 2:
917 fn = twoway_merge;
918 break;
919 case 3:
920 default:
921 fn = threeway_merge;
922 cache_tree_free(&active_cache_tree);
923 break;
924 }
925 if (stage - 1 >= 3)
927 head_idx = stage - 2;
928 else
929 head_idx = 1;
930 }
931 unpack_trees(fn);
933 /*
935 * When reading only one tree (either the most basic form,
936 * "-m ent" or "--reset ent" form), we can obtain a fully
937 * valid cache-tree because the index must match exactly
938 * what came from the tree.
939 */
940 if (trees->item && !prefix && (!merge || (stage == 2))) {
941 cache_tree_free(&active_cache_tree);
942 prime_cache_tree();
943 }
944 if (write_cache(newfd, active_cache, active_nr) ||
946 commit_index_file(&cache_file))
947 die("unable to write new index file");
948 return 0;
949}