t1000: fix case table.
[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
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6#include "unpack-trees.h"
7
076b0adc
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8#define DBRT_DEBUG 1
9
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10struct tree_entry_list {
11 struct tree_entry_list *next;
12 unsigned directory : 1;
13 unsigned executable : 1;
14 unsigned symlink : 1;
15 unsigned int mode;
16 const char *name;
17 const unsigned char *sha1;
18};
19
20static struct tree_entry_list *create_tree_entry_list(struct tree *tree)
21{
22 struct tree_desc desc;
23 struct name_entry one;
24 struct tree_entry_list *ret = NULL;
25 struct tree_entry_list **list_p = &ret;
26
076b0adc
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27 if (!tree->object.parsed)
28 parse_tree(tree);
29
6fda5e51 30 init_tree_desc(&desc, tree->buffer, tree->size);
16da134b
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31
32 while (tree_entry(&desc, &one)) {
33 struct tree_entry_list *entry;
34
35 entry = xmalloc(sizeof(struct tree_entry_list));
36 entry->name = one.path;
37 entry->sha1 = one.sha1;
38 entry->mode = one.mode;
39 entry->directory = S_ISDIR(one.mode) != 0;
40 entry->executable = (one.mode & S_IXUSR) != 0;
41 entry->symlink = S_ISLNK(one.mode) != 0;
42 entry->next = NULL;
43
44 *list_p = entry;
45 list_p = &entry->next;
46 }
47 return ret;
48}
49
50static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
51{
52 int len1 = strlen(name1);
53 int len2 = strlen(name2);
54 int len = len1 < len2 ? len1 : len2;
55 int ret = memcmp(name1, name2, len);
56 unsigned char c1, c2;
57 if (ret)
58 return ret;
59 c1 = name1[len];
60 c2 = name2[len];
61 if (!c1 && dir1)
62 c1 = '/';
63 if (!c2 && dir2)
64 c2 = '/';
65 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
66 if (c1 && c2 && !ret)
67 ret = len1 - len2;
68 return ret;
69}
70
71static int unpack_trees_rec(struct tree_entry_list **posns, int len,
72 const char *base, struct unpack_trees_options *o,
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73 struct tree_entry_list *df_conflict_list)
74{
75 int baselen = strlen(base);
76 int src_size = len + 1;
f8a9d428
JH
77 int i_stk = i_stk;
78 int retval = 0;
79
80 if (o->dir)
81 i_stk = push_exclude_per_directory(o->dir, base, strlen(base));
82
16da134b
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83 do {
84 int i;
85 const char *first;
86 int firstdir = 0;
87 int pathlen;
88 unsigned ce_size;
89 struct tree_entry_list **subposns;
90 struct cache_entry **src;
91 int any_files = 0;
92 int any_dirs = 0;
93 char *cache_name;
94 int ce_stage;
95
96 /* Find the first name in the input. */
97
98 first = NULL;
99 cache_name = NULL;
100
101 /* Check the cache */
9a4d8fdc 102 if (o->merge && o->pos < active_nr) {
16da134b
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103 /* This is a bit tricky: */
104 /* If the index has a subdirectory (with
105 * contents) as the first name, it'll get a
106 * filename like "foo/bar". But that's after
107 * "foo", so the entry in trees will get
108 * handled first, at which point we'll go into
109 * "foo", and deal with "bar" from the index,
110 * because the base will be "foo/". The only
111 * way we can actually have "foo/bar" first of
112 * all the things is if the trees don't
113 * contain "foo" at all, in which case we'll
114 * handle "foo/bar" without going into the
115 * directory, but that's fine (and will return
116 * an error anyway, with the added unknown
117 * file case.
118 */
119
9a4d8fdc 120 cache_name = active_cache[o->pos]->name;
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121 if (strlen(cache_name) > baselen &&
122 !memcmp(cache_name, base, baselen)) {
123 cache_name += baselen;
124 first = cache_name;
125 } else {
126 cache_name = NULL;
127 }
128 }
129
130#if DBRT_DEBUG > 1
131 if (first)
132 printf("index %s\n", first);
133#endif
134 for (i = 0; i < len; i++) {
135 if (!posns[i] || posns[i] == df_conflict_list)
136 continue;
137#if DBRT_DEBUG > 1
138 printf("%d %s\n", i + 1, posns[i]->name);
139#endif
140 if (!first || entcmp(first, firstdir,
141 posns[i]->name,
142 posns[i]->directory) > 0) {
143 first = posns[i]->name;
144 firstdir = posns[i]->directory;
145 }
146 }
147 /* No name means we're done */
148 if (!first)
f8a9d428 149 goto leave_directory;
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150
151 pathlen = strlen(first);
152 ce_size = cache_entry_size(baselen + pathlen);
153
154 src = xcalloc(src_size, sizeof(struct cache_entry *));
155
156 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
157
158 if (cache_name && !strcmp(cache_name, first)) {
159 any_files = 1;
9a4d8fdc
JH
160 src[0] = active_cache[o->pos];
161 remove_cache_entry_at(o->pos);
16da134b
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162 }
163
164 for (i = 0; i < len; i++) {
165 struct cache_entry *ce;
166
167 if (!posns[i] ||
168 (posns[i] != df_conflict_list &&
169 strcmp(first, posns[i]->name))) {
170 continue;
171 }
172
173 if (posns[i] == df_conflict_list) {
174 src[i + o->merge] = o->df_conflict_entry;
175 continue;
176 }
177
178 if (posns[i]->directory) {
179 struct tree *tree = lookup_tree(posns[i]->sha1);
180 any_dirs = 1;
181 parse_tree(tree);
182 subposns[i] = create_tree_entry_list(tree);
183 posns[i] = posns[i]->next;
184 src[i + o->merge] = o->df_conflict_entry;
185 continue;
186 }
187
188 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
197 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
204 any_files = 1;
205
e702496e 206 hashcpy(ce->sha1, posns[i]->sha1);
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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
215#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);
226
227#if DBRT_DEBUG > 1
228 printf("Added %d entries\n", ret);
229#endif
9a4d8fdc 230 o->pos += ret;
16da134b
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231 } else {
232 for (i = 0; i < src_size; i++) {
233 if (src[i]) {
234 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
235 }
236 }
237 }
238 }
239 if (any_dirs) {
240 char *newbase = xmalloc(baselen + 2 + pathlen);
241 memcpy(newbase, base, baselen);
242 memcpy(newbase + baselen, first, pathlen);
243 newbase[baselen + pathlen] = '/';
244 newbase[baselen + pathlen + 1] = '\0';
245 if (unpack_trees_rec(subposns, len, newbase, o,
9a4d8fdc 246 df_conflict_list)) {
f8a9d428
JH
247 retval = -1;
248 goto leave_directory;
249 }
16da134b
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250 free(newbase);
251 }
252 free(subposns);
253 free(src);
254 } while (1);
f8a9d428
JH
255
256 leave_directory:
257 if (o->dir)
258 pop_exclude_per_directory(o->dir, i_stk);
259 return retval;
16da134b
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260}
261
262/* Unlink the last component and attempt to remove leading
263 * directories, in case this unlink is the removal of the
264 * last entry in the directory -- empty directories are removed.
265 */
266static void unlink_entry(char *name)
267{
268 char *cp, *prev;
269
270 if (unlink(name))
271 return;
272 prev = NULL;
273 while (1) {
274 int status;
275 cp = strrchr(name, '/');
276 if (prev)
277 *prev = '/';
278 if (!cp)
279 break;
280
281 *cp = 0;
282 status = rmdir(name);
283 if (status) {
284 *cp = '/';
285 break;
286 }
287 prev = cp;
288 }
289}
290
96f1e58f 291static volatile sig_atomic_t progress_update;
16da134b
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292
293static void progress_interval(int signum)
294{
295 progress_update = 1;
296}
297
298static void setup_progress_signal(void)
299{
300 struct sigaction sa;
301 struct itimerval v;
302
303 memset(&sa, 0, sizeof(sa));
304 sa.sa_handler = progress_interval;
305 sigemptyset(&sa.sa_mask);
306 sa.sa_flags = SA_RESTART;
307 sigaction(SIGALRM, &sa, NULL);
308
309 v.it_interval.tv_sec = 1;
310 v.it_interval.tv_usec = 0;
311 v.it_value = v.it_interval;
312 setitimer(ITIMER_REAL, &v, NULL);
313}
314
315static struct checkout state;
316static void check_updates(struct cache_entry **src, int nr,
317 struct unpack_trees_options *o)
318{
319 unsigned short mask = htons(CE_UPDATE);
320 unsigned last_percent = 200, cnt = 0, total = 0;
321
322 if (o->update && o->verbose_update) {
323 for (total = cnt = 0; cnt < nr; cnt++) {
324 struct cache_entry *ce = src[cnt];
325 if (!ce->ce_mode || ce->ce_flags & mask)
326 total++;
327 }
328
329 /* Don't bother doing this for very small updates */
330 if (total < 250)
331 total = 0;
332
333 if (total) {
334 fprintf(stderr, "Checking files out...\n");
335 setup_progress_signal();
336 progress_update = 1;
337 }
338 cnt = 0;
339 }
340
341 while (nr--) {
342 struct cache_entry *ce = *src++;
343
344 if (total) {
345 if (!ce->ce_mode || ce->ce_flags & mask) {
346 unsigned percent;
347 cnt++;
348 percent = (cnt * 100) / total;
349 if (percent != last_percent ||
350 progress_update) {
351 fprintf(stderr, "%4u%% (%u/%u) done\r",
352 percent, cnt, total);
353 last_percent = percent;
354 progress_update = 0;
355 }
356 }
357 }
358 if (!ce->ce_mode) {
359 if (o->update)
360 unlink_entry(ce->name);
361 continue;
362 }
363 if (ce->ce_flags & mask) {
364 ce->ce_flags &= ~mask;
365 if (o->update)
366 checkout_entry(ce, &state, NULL);
367 }
368 }
369 if (total) {
370 signal(SIGALRM, SIG_IGN);
371 fputc('\n', stderr);
372 }
373}
374
375int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
376{
16da134b
JS
377 unsigned len = object_list_length(trees);
378 struct tree_entry_list **posns;
379 int i;
380 struct object_list *posn = trees;
381 struct tree_entry_list df_conflict_list;
0fb1eaa8 382 static struct cache_entry *dfc;
16da134b
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383
384 memset(&df_conflict_list, 0, sizeof(df_conflict_list));
385 df_conflict_list.next = &df_conflict_list;
076b0adc 386 memset(&state, 0, sizeof(state));
16da134b
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387 state.base_dir = "";
388 state.force = 1;
389 state.quiet = 1;
390 state.refresh_cache = 1;
391
392 o->merge_size = len;
0fb1eaa8
JH
393
394 if (!dfc)
395 dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
396 o->df_conflict_entry = dfc;
16da134b
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397
398 if (len) {
399 posns = xmalloc(len * sizeof(struct tree_entry_list *));
400 for (i = 0; i < len; i++) {
401 posns[i] = create_tree_entry_list((struct tree *) posn->item);
402 posn = posn->next;
403 }
404 if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
9a4d8fdc 405 o, &df_conflict_list))
16da134b
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406 return -1;
407 }
408
409 if (o->trivial_merges_only && o->nontrivial_merge)
410 die("Merge requires file-level merging");
411
412 check_updates(active_cache, active_nr, o);
413 return 0;
414}
076b0adc
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415
416/* Here come the merge functions */
417
418static void reject_merge(struct cache_entry *ce)
419{
420 die("Entry '%s' would be overwritten by merge. Cannot merge.",
421 ce->name);
422}
423
424static int same(struct cache_entry *a, struct cache_entry *b)
425{
426 if (!!a != !!b)
427 return 0;
428 if (!a && !b)
429 return 1;
430 return a->ce_mode == b->ce_mode &&
a89fccd2 431 !hashcmp(a->sha1, b->sha1);
076b0adc
JS
432}
433
434
435/*
436 * When a CE gets turned into an unmerged entry, we
437 * want it to be up-to-date
438 */
439static void verify_uptodate(struct cache_entry *ce,
440 struct unpack_trees_options *o)
441{
442 struct stat st;
443
444 if (o->index_only || o->reset)
445 return;
446
447 if (!lstat(ce->name, &st)) {
448 unsigned changed = ce_match_stat(ce, &st, 1);
449 if (!changed)
450 return;
451 errno = 0;
452 }
453 if (o->reset) {
454 ce->ce_flags |= htons(CE_UPDATE);
455 return;
456 }
457 if (errno == ENOENT)
458 return;
459 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
460}
461
462static void invalidate_ce_path(struct cache_entry *ce)
463{
464 if (ce)
465 cache_tree_invalidate_path(active_cache_tree, ce->name);
466}
467
c8193534
JH
468static int verify_clean_subdirectory(const char *path, const char *action,
469 struct unpack_trees_options *o)
470{
471 /*
472 * we are about to extract "path"; we would not want to lose
473 * anything in the existing directory there.
474 */
475 int namelen;
476 int pos, i;
477 struct dir_struct d;
478 char *pathbuf;
479 int cnt = 0;
480
481 /*
482 * First let's make sure we do not have a local modification
483 * in that directory.
484 */
485 namelen = strlen(path);
486 pos = cache_name_pos(path, namelen);
487 if (0 <= pos)
488 return cnt; /* we have it as nondirectory */
489 pos = -pos - 1;
490 for (i = pos; i < active_nr; i++) {
491 struct cache_entry *ce = active_cache[i];
492 int len = ce_namelen(ce);
493 if (len < namelen ||
494 strncmp(path, ce->name, namelen) ||
495 ce->name[namelen] != '/')
496 break;
497 /*
498 * ce->name is an entry in the subdirectory.
499 */
500 if (!ce_stage(ce)) {
501 verify_uptodate(ce, o);
502 ce->ce_mode = 0;
503 }
504 cnt++;
505 }
506
507 /*
508 * Then we need to make sure that we do not lose a locally
509 * present file that is not ignored.
510 */
511 pathbuf = xmalloc(namelen + 2);
512 memcpy(pathbuf, path, namelen);
513 strcpy(pathbuf+namelen, "/");
514
515 memset(&d, 0, sizeof(d));
516 if (o->dir)
517 d.exclude_per_dir = o->dir->exclude_per_dir;
518 i = read_directory(&d, path, pathbuf, namelen+1, NULL);
519 if (i)
520 die("Updating '%s' would lose untracked files in it",
521 path);
522 free(pathbuf);
523 return cnt;
524}
525
076b0adc
JS
526/*
527 * We do not want to remove or overwrite a working tree file that
f8a9d428 528 * is not tracked, unless it is ignored.
076b0adc
JS
529 */
530static void verify_absent(const char *path, const char *action,
531 struct unpack_trees_options *o)
532{
533 struct stat st;
534
535 if (o->index_only || o->reset || !o->update)
536 return;
c8193534
JH
537
538 if (!lstat(path, &st)) {
539 int cnt;
540
541 if (o->dir && excluded(o->dir, path))
542 /*
543 * path is explicitly excluded, so it is Ok to
544 * overwrite it.
545 */
546 return;
547 if (S_ISDIR(st.st_mode)) {
548 /*
549 * We are checking out path "foo" and
550 * found "foo/." in the working tree.
551 * This is tricky -- if we have modified
552 * files that are in "foo/" we would lose
553 * it.
554 */
555 cnt = verify_clean_subdirectory(path, action, o);
556
557 /*
558 * If this removed entries from the index,
559 * what that means is:
560 *
561 * (1) the caller unpack_trees_rec() saw path/foo
562 * in the index, and it has not removed it because
563 * it thinks it is handling 'path' as blob with
564 * D/F conflict;
565 * (2) we will return "ok, we placed a merged entry
566 * in the index" which would cause o->pos to be
567 * incremented by one;
568 * (3) however, original o->pos now has 'path/foo'
569 * marked with "to be removed".
570 *
571 * We need to increment it by the number of
572 * deleted entries here.
573 */
574 o->pos += cnt;
575 return;
576 }
577
578 /*
579 * The previous round may already have decided to
580 * delete this path, which is in a subdirectory that
581 * is being replaced with a blob.
582 */
583 cnt = cache_name_pos(path, strlen(path));
584 if (0 <= cnt) {
585 struct cache_entry *ce = active_cache[cnt];
586 if (!ce_stage(ce) && !ce->ce_mode)
587 return;
588 }
589
076b0adc
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590 die("Untracked working tree file '%s' "
591 "would be %s by merge.", path, action);
c8193534 592 }
076b0adc
JS
593}
594
595static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
596 struct unpack_trees_options *o)
597{
598 merge->ce_flags |= htons(CE_UPDATE);
599 if (old) {
600 /*
601 * See if we can re-use the old CE directly?
602 * That way we get the uptodate stat info.
603 *
604 * This also removes the UPDATE flag on
605 * a match.
606 */
607 if (same(old, merge)) {
608 *merge = *old;
609 } else {
610 verify_uptodate(old, o);
611 invalidate_ce_path(old);
612 }
613 }
614 else {
615 verify_absent(merge->name, "overwritten", o);
616 invalidate_ce_path(merge);
617 }
618
619 merge->ce_flags &= ~htons(CE_STAGEMASK);
620 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
621 return 1;
622}
623
624static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
625 struct unpack_trees_options *o)
626{
627 if (old)
628 verify_uptodate(old, o);
629 else
630 verify_absent(ce->name, "removed", o);
631 ce->ce_mode = 0;
632 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
633 invalidate_ce_path(ce);
634 return 1;
635}
636
7f7932ab 637static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
076b0adc
JS
638{
639 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
640 return 1;
641}
642
643#if DBRT_DEBUG
644static void show_stage_entry(FILE *o,
645 const char *label, const struct cache_entry *ce)
646{
647 if (!ce)
648 fprintf(o, "%s (missing)\n", label);
649 else
650 fprintf(o, "%s%06o %s %d\t%s\n",
651 label,
652 ntohl(ce->ce_mode),
653 sha1_to_hex(ce->sha1),
654 ce_stage(ce),
655 ce->name);
656}
657#endif
658
659int threeway_merge(struct cache_entry **stages,
660 struct unpack_trees_options *o)
661{
662 struct cache_entry *index;
663 struct cache_entry *head;
664 struct cache_entry *remote = stages[o->head_idx + 1];
665 int count;
666 int head_match = 0;
667 int remote_match = 0;
668 const char *path = NULL;
669
670 int df_conflict_head = 0;
671 int df_conflict_remote = 0;
672
673 int any_anc_missing = 0;
674 int no_anc_exists = 1;
675 int i;
676
677 for (i = 1; i < o->head_idx; i++) {
678 if (!stages[i])
679 any_anc_missing = 1;
680 else {
681 if (!path)
682 path = stages[i]->name;
683 no_anc_exists = 0;
684 }
685 }
686
687 index = stages[0];
688 head = stages[o->head_idx];
689
690 if (head == o->df_conflict_entry) {
691 df_conflict_head = 1;
692 head = NULL;
693 }
694
695 if (remote == o->df_conflict_entry) {
696 df_conflict_remote = 1;
697 remote = NULL;
698 }
699
700 if (!path && index)
701 path = index->name;
702 if (!path && head)
703 path = head->name;
704 if (!path && remote)
705 path = remote->name;
706
707 /* First, if there's a #16 situation, note that to prevent #13
708 * and #14.
709 */
710 if (!same(remote, head)) {
711 for (i = 1; i < o->head_idx; i++) {
712 if (same(stages[i], head)) {
713 head_match = i;
714 }
715 if (same(stages[i], remote)) {
716 remote_match = i;
717 }
718 }
719 }
720
721 /* We start with cases where the index is allowed to match
722 * something other than the head: #14(ALT) and #2ALT, where it
723 * is permitted to match the result instead.
724 */
725 /* #14, #14ALT, #2ALT */
726 if (remote && !df_conflict_head && head_match && !remote_match) {
727 if (index && !same(index, remote) && !same(index, head))
728 reject_merge(index);
729 return merged_entry(remote, index, o);
730 }
731 /*
732 * If we have an entry in the index cache, then we want to
733 * make sure that it matches head.
734 */
735 if (index && !same(index, head)) {
736 reject_merge(index);
737 }
738
739 if (head) {
740 /* #5ALT, #15 */
741 if (same(head, remote))
742 return merged_entry(head, index, o);
743 /* #13, #3ALT */
744 if (!df_conflict_remote && remote_match && !head_match)
745 return merged_entry(head, index, o);
746 }
747
748 /* #1 */
749 if (!head && !remote && any_anc_missing)
750 return 0;
751
752 /* Under the new "aggressive" rule, we resolve mostly trivial
753 * cases that we historically had git-merge-one-file resolve.
754 */
755 if (o->aggressive) {
756 int head_deleted = !head && !df_conflict_head;
757 int remote_deleted = !remote && !df_conflict_remote;
758 /*
759 * Deleted in both.
760 * Deleted in one and unchanged in the other.
761 */
762 if ((head_deleted && remote_deleted) ||
763 (head_deleted && remote && remote_match) ||
764 (remote_deleted && head && head_match)) {
765 if (index)
766 return deleted_entry(index, index, o);
ed93b449 767 else if (path && !head_deleted)
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768 verify_absent(path, "removed", o);
769 return 0;
770 }
771 /*
772 * Added in both, identically.
773 */
774 if (no_anc_exists && head && remote && same(head, remote))
775 return merged_entry(head, index, o);
776
777 }
778
779 /* Below are "no merge" cases, which require that the index be
780 * up-to-date to avoid the files getting overwritten with
781 * conflict resolution files.
782 */
783 if (index) {
784 verify_uptodate(index, o);
785 }
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786
787 o->nontrivial_merge = 1;
788
ea4b52a8 789 /* #2, #3, #4, #6, #7, #9, #10, #11. */
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790 count = 0;
791 if (!head_match || !remote_match) {
792 for (i = 1; i < o->head_idx; i++) {
793 if (stages[i]) {
7f7932ab 794 keep_entry(stages[i], o);
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795 count++;
796 break;
797 }
798 }
799 }
800#if DBRT_DEBUG
801 else {
802 fprintf(stderr, "read-tree: warning #16 detected\n");
803 show_stage_entry(stderr, "head ", stages[head_match]);
804 show_stage_entry(stderr, "remote ", stages[remote_match]);
805 }
806#endif
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807 if (head) { count += keep_entry(head, o); }
808 if (remote) { count += keep_entry(remote, o); }
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809 return count;
810}
811
812/*
813 * Two-way merge.
814 *
815 * The rule is to "carry forward" what is in the index without losing
816 * information across a "fast forward", favoring a successful merge
817 * over a merge failure when it makes sense. For details of the
818 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
819 *
820 */
821int twoway_merge(struct cache_entry **src,
822 struct unpack_trees_options *o)
823{
824 struct cache_entry *current = src[0];
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825 struct cache_entry *oldtree = src[1];
826 struct cache_entry *newtree = src[2];
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827
828 if (o->merge_size != 2)
829 return error("Cannot do a twoway merge of %d trees",
830 o->merge_size);
831
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832 if (oldtree == o->df_conflict_entry)
833 oldtree = NULL;
834 if (newtree == o->df_conflict_entry)
835 newtree = NULL;
836
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837 if (current) {
838 if ((!oldtree && !newtree) || /* 4 and 5 */
839 (!oldtree && newtree &&
840 same(current, newtree)) || /* 6 and 7 */
841 (oldtree && newtree &&
842 same(oldtree, newtree)) || /* 14 and 15 */
843 (oldtree && newtree &&
b8ba1535 844 !same(oldtree, newtree) && /* 18 and 19 */
076b0adc 845 same(current, newtree))) {
7f7932ab 846 return keep_entry(current, o);
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847 }
848 else if (oldtree && !newtree && same(current, oldtree)) {
849 /* 10 or 11 */
850 return deleted_entry(oldtree, current, o);
851 }
852 else if (oldtree && newtree &&
853 same(current, oldtree) && !same(current, newtree)) {
854 /* 20 or 21 */
855 return merged_entry(newtree, current, o);
856 }
857 else {
858 /* all other failures */
859 if (oldtree)
860 reject_merge(oldtree);
861 if (current)
862 reject_merge(current);
863 if (newtree)
864 reject_merge(newtree);
865 return -1;
866 }
867 }
868 else if (newtree)
869 return merged_entry(newtree, current, o);
870 else
871 return deleted_entry(oldtree, current, o);
872}
873
874/*
875 * Bind merge.
876 *
877 * Keep the index entries at stage0, collapse stage1 but make sure
878 * stage0 does not have anything there.
879 */
880int bind_merge(struct cache_entry **src,
881 struct unpack_trees_options *o)
882{
883 struct cache_entry *old = src[0];
884 struct cache_entry *a = src[1];
885
886 if (o->merge_size != 1)
887 return error("Cannot do a bind merge of %d trees\n",
888 o->merge_size);
889 if (a && old)
890 die("Entry '%s' overlaps. Cannot bind.", a->name);
891 if (!a)
7f7932ab 892 return keep_entry(old, o);
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893 else
894 return merged_entry(a, NULL, o);
895}
896
897/*
898 * One-way merge.
899 *
900 * The rule is:
901 * - take the stat information from stage0, take the data from stage1
902 */
903int oneway_merge(struct cache_entry **src,
904 struct unpack_trees_options *o)
905{
906 struct cache_entry *old = src[0];
907 struct cache_entry *a = src[1];
908
909 if (o->merge_size != 1)
910 return error("Cannot do a oneway merge of %d trees",
911 o->merge_size);
912
913 if (!a)
914 return deleted_entry(old, old, o);
915 if (old && same(old, a)) {
916 if (o->reset) {
917 struct stat st;
918 if (lstat(old->name, &st) ||
919 ce_match_stat(old, &st, 1))
920 old->ce_flags |= htons(CE_UPDATE);
921 }
7f7932ab 922 return keep_entry(old, o);
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923 }
924 return merged_entry(a, old, o);
925}