Plug leak in Daniel's read-tree.
[git/git.git] / read-tree.c
CommitLineData
8bc9a0c7
LT
1/*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
4d3fe0c5
JH
6#define DBRT_DEBUG 1
7
e83c5163
LT
8#include "cache.h"
9
ee6566e8
DB
10#include "object.h"
11#include "tree.h"
12
13static int merge = 0;
220a0b52 14static int update = 0;
d99082e0 15
ee6566e8
DB
16static int head_idx = -1;
17static int merge_size = 0;
b12ec373 18
ee6566e8
DB
19static struct object_list *trees = NULL;
20
21static struct cache_entry df_conflict_entry = {
22};
23
24static struct tree_entry_list df_conflict_list = {
25 .name = NULL,
26 .next = &df_conflict_list
27};
28
29typedef int (*merge_fn_t)(struct cache_entry **src);
30
31static int entcmp(char *name1, int dir1, char *name2, int dir2)
32{
33 int len1 = strlen(name1);
34 int len2 = strlen(name2);
35 int len = len1 < len2 ? len1 : len2;
36 int ret = memcmp(name1, name2, len);
37 unsigned char c1, c2;
38 if (ret)
39 return ret;
40 c1 = name1[len];
41 c2 = name2[len];
42 if (!c1 && dir1)
43 c1 = '/';
44 if (!c2 && dir2)
45 c2 = '/';
46 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
47 if (c1 && c2 && !ret)
48 ret = len1 - len2;
14242464 49 return ret;
b12ec373
JH
50}
51
ee6566e8
DB
52static int unpack_trees_rec(struct tree_entry_list **posns, int len,
53 const char *base, merge_fn_t fn, int *indpos)
ca016f0e 54{
ee6566e8
DB
55 int baselen = strlen(base);
56 int src_size = len + 1;
57 do {
58 int i;
59 char *first;
60 int firstdir = 0;
61 int pathlen;
62 unsigned ce_size;
63 struct tree_entry_list **subposns;
64 struct cache_entry **src;
65 int any_files = 0;
66 int any_dirs = 0;
67 char *cache_name;
68 int ce_stage;
69
70 /* Find the first name in the input. */
71
72 first = NULL;
73 cache_name = NULL;
74
75 /* Check the cache */
76 if (merge && *indpos < active_nr) {
77 /* This is a bit tricky: */
78 /* If the index has a subdirectory (with
79 * contents) as the first name, it'll get a
80 * filename like "foo/bar". But that's after
81 * "foo", so the entry in trees will get
82 * handled first, at which point we'll go into
83 * "foo", and deal with "bar" from the index,
84 * because the base will be "foo/". The only
85 * way we can actually have "foo/bar" first of
86 * all the things is if the trees don't
87 * contain "foo" at all, in which case we'll
88 * handle "foo/bar" without going into the
89 * directory, but that's fine (and will return
90 * an error anyway, with the added unknown
91 * file case.
92 */
93
94 cache_name = active_cache[*indpos]->name;
95 if (strlen(cache_name) > baselen &&
96 !memcmp(cache_name, base, baselen)) {
97 cache_name += baselen;
98 first = cache_name;
99 } else {
100 cache_name = NULL;
101 }
102 }
103
4d3fe0c5 104#if DBRT_DEBUG > 1
ee6566e8
DB
105 if (first)
106 printf("index %s\n", first);
2ab706a3 107#endif
ee6566e8
DB
108 for (i = 0; i < len; i++) {
109 if (!posns[i] || posns[i] == &df_conflict_list)
110 continue;
4d3fe0c5 111#if DBRT_DEBUG > 1
ee6566e8 112 printf("%d %s\n", i + 1, posns[i]->name);
2ab706a3 113#endif
ee6566e8
DB
114 if (!first || entcmp(first, firstdir,
115 posns[i]->name,
116 posns[i]->directory) > 0) {
117 first = posns[i]->name;
118 firstdir = posns[i]->directory;
119 }
120 }
121 /* No name means we're done */
122 if (!first)
123 return 0;
124
125 pathlen = strlen(first);
126 ce_size = cache_entry_size(baselen + pathlen);
127
128 src = xmalloc(sizeof(struct cache_entry *) * src_size);
129 memset(src, 0, sizeof(struct cache_entry *) * src_size);
130
131 subposns = xmalloc(sizeof(struct tree_list_entry *) * len);
132 memset(subposns, 0, sizeof(struct tree_list_entry *) * len);
133
134 if (cache_name && !strcmp(cache_name, first)) {
135 any_files = 1;
136 src[0] = active_cache[*indpos];
137 remove_cache_entry_at(*indpos);
138 }
139
140 for (i = 0; i < len; i++) {
141 struct cache_entry *ce;
142
143 if (!posns[i] ||
144 (posns[i] != &df_conflict_list &&
145 strcmp(first, posns[i]->name))) {
146 continue;
147 }
148
149 if (posns[i] == &df_conflict_list) {
150 src[i + merge] = &df_conflict_entry;
151 continue;
152 }
153
154 if (posns[i]->directory) {
155 any_dirs = 1;
156 parse_tree(posns[i]->item.tree);
157 subposns[i] = posns[i]->item.tree->entries;
158 posns[i] = posns[i]->next;
159 src[i + merge] = &df_conflict_entry;
160 continue;
161 }
162
163 if (!merge)
164 ce_stage = 0;
165 else if (i + 1 < head_idx)
166 ce_stage = 1;
167 else if (i + 1 > head_idx)
168 ce_stage = 3;
169 else
170 ce_stage = 2;
171
172 ce = xmalloc(ce_size);
173 memset(ce, 0, ce_size);
174 ce->ce_mode = create_ce_mode(posns[i]->mode);
175 ce->ce_flags = create_ce_flags(baselen + pathlen,
176 ce_stage);
177 memcpy(ce->name, base, baselen);
178 memcpy(ce->name + baselen, first, pathlen + 1);
179
180 any_files = 1;
181
182 memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
183 src[i + merge] = ce;
184 subposns[i] = &df_conflict_list;
185 posns[i] = posns[i]->next;
186 }
187 if (any_files) {
188 if (merge) {
189 int ret;
190
4d3fe0c5 191#if DBRT_DEBUG > 1
ee6566e8
DB
192 printf("%s:\n", first);
193 for (i = 0; i < src_size; i++) {
194 printf(" %d ", i);
195 if (src[i])
196 printf("%s\n", sha1_to_hex(src[i]->sha1));
197 else
198 printf("\n");
199 }
2ab706a3 200#endif
ee6566e8
DB
201 ret = fn(src);
202
4d3fe0c5 203#if DBRT_DEBUG > 1
ee6566e8 204 printf("Added %d entries\n", ret);
2ab706a3 205#endif
ee6566e8
DB
206 *indpos += ret;
207 } else {
208 for (i = 0; i < src_size; i++) {
209 if (src[i]) {
210 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
211 }
212 }
213 }
214 }
215 if (any_dirs) {
216 char *newbase = xmalloc(baselen + 2 + pathlen);
217 memcpy(newbase, base, baselen);
218 memcpy(newbase + baselen, first, pathlen);
219 newbase[baselen + pathlen] = '/';
220 newbase[baselen + pathlen + 1] = '\0';
221 if (unpack_trees_rec(subposns, len, newbase, fn,
222 indpos))
223 return -1;
bb97a2a8 224 free(newbase);
ee6566e8
DB
225 }
226 free(subposns);
227 free(src);
228 } while (1);
ca016f0e
LT
229}
230
ee6566e8 231static void reject_merge(struct cache_entry *ce)
43f91266 232{
ee6566e8
DB
233 die("Entry '%s' would be overwritten by merge. Cannot merge.",
234 ce->name);
43f91266
LT
235}
236
ee6566e8
DB
237static void check_updates(struct cache_entry **src, int nr)
238{
239 static struct checkout state = {
240 .base_dir = "",
241 .force = 1,
242 .quiet = 1,
243 .refresh_cache = 1,
244 };
245 unsigned short mask = htons(CE_UPDATE);
246 while (nr--) {
247 struct cache_entry *ce = *src++;
248 if (!ce->ce_mode) {
249 if (update)
250 unlink(ce->name);
251 continue;
252 }
253 if (ce->ce_flags & mask) {
254 ce->ce_flags &= ~mask;
255 if (update)
256 checkout_entry(ce, &state);
257 }
258 }
259}
43f91266 260
ee6566e8 261static int unpack_trees(merge_fn_t fn)
d99082e0 262{
ee6566e8
DB
263 int indpos = 0;
264 unsigned len = object_list_length(trees);
265 struct tree_entry_list **posns =
266 xmalloc(len * sizeof(struct tree_entry_list *));
267 int i;
268 struct object_list *posn = trees;
269 merge_size = len;
270 for (i = 0; i < len; i++) {
271 posns[i] = ((struct tree *) posn->item)->entries;
272 posn = posn->next;
d723c690 273 }
ee6566e8
DB
274 if (unpack_trees_rec(posns, len, "", fn, &indpos))
275 return -1;
276
277 check_updates(active_cache, active_nr);
278 return 0;
d99082e0
LT
279}
280
ee6566e8
DB
281static int list_tree(unsigned char *sha1)
282{
283 struct tree *tree = parse_tree_indirect(sha1);
284 if (!tree)
285 return -1;
286 object_list_append(&tree->object, &trees);
287 return 0;
288}
289
290static int same(struct cache_entry *a, struct cache_entry *b)
291{
292 if (!!a != !!b)
293 return 0;
294 if (!a && !b)
295 return 1;
296 return a->ce_mode == b->ce_mode &&
297 !memcmp(a->sha1, b->sha1, 20);
298}
299
300
02ede67a
LT
301/*
302 * When a CE gets turned into an unmerged entry, we
303 * want it to be up-to-date
304 */
305static void verify_uptodate(struct cache_entry *ce)
306{
307 struct stat st;
308
309 if (!lstat(ce->name, &st)) {
310 unsigned changed = ce_match_stat(ce, &st);
311 if (!changed)
312 return;
313 errno = 0;
314 }
315 if (errno == ENOENT)
316 return;
317 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
318}
319
ee6566e8 320static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
d99082e0 321{
d723c690
LT
322 merge->ce_flags |= htons(CE_UPDATE);
323 if (old) {
02ede67a 324 /*
d723c690
LT
325 * See if we can re-use the old CE directly?
326 * That way we get the uptodate stat info.
327 *
328 * This also removes the UPDATE flag on
329 * a match.
02ede67a 330 */
d723c690
LT
331 if (same(old, merge)) {
332 *merge = *old;
ee6566e8 333 } else {
d723c690
LT
334 verify_uptodate(old);
335 }
a3a65234 336 }
d723c690 337 merge->ce_flags &= ~htons(CE_STAGEMASK);
ee6566e8 338 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
d723c690 339 return 1;
a3a65234
LT
340}
341
ee6566e8 342static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
aa16021e
LT
343{
344 if (old)
345 verify_uptodate(old);
346 ce->ce_mode = 0;
ee6566e8 347 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
aa16021e
LT
348 return 1;
349}
350
ee6566e8 351static int keep_entry(struct cache_entry *ce)
32192e66 352{
ee6566e8
DB
353 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
354 return 1;
32192e66
JH
355}
356
4d3fe0c5
JH
357#if DBRT_DEBUG
358static void show_stage_entry(FILE *o,
359 const char *label, const struct cache_entry *ce)
360{
361 fprintf(stderr, "%s%06o %s %d\t%s\n",
362 label,
363 ntohl(ce->ce_mode),
364 sha1_to_hex(ce->sha1),
365 ce_stage(ce),
366 ce->name);
367}
368#endif
369
ee6566e8 370static int threeway_merge(struct cache_entry **stages)
e6ee623b 371{
ee6566e8
DB
372 struct cache_entry *index;
373 struct cache_entry *head;
374 struct cache_entry *remote = stages[head_idx + 1];
d723c690 375 int count;
ee6566e8
DB
376 int head_match = 0;
377 int remote_match = 0;
d723c690 378
ee6566e8
DB
379 int df_conflict_head = 0;
380 int df_conflict_remote = 0;
381
382 int any_anc_missing = 0;
383 int i;
384
385 for (i = 1; i < head_idx; i++) {
386 if (!stages[i])
387 any_anc_missing = 1;
e7f9bc41 388 }
ee6566e8
DB
389
390 index = stages[0];
391 head = stages[head_idx];
392
393 if (head == &df_conflict_entry) {
394 df_conflict_head = 1;
395 head = NULL;
396 }
397
398 if (remote == &df_conflict_entry) {
399 df_conflict_remote = 1;
400 remote = NULL;
401 }
402
403 /* First, if there's a #16 situation, note that to prevent #13
404 * and #14.
405 */
406 if (!same(remote, head)) {
407 for (i = 1; i < head_idx; i++) {
408 if (same(stages[i], head)) {
4d3fe0c5 409 head_match = i;
ee6566e8
DB
410 }
411 if (same(stages[i], remote)) {
4d3fe0c5 412 remote_match = i;
ee6566e8 413 }
32192e66 414 }
32192e66 415 }
ee6566e8
DB
416
417 /* We start with cases where the index is allowed to match
418 * something other than the head: #14(ALT) and #2ALT, where it
419 * is permitted to match the result instead.
420 */
421 /* #14, #14ALT, #2ALT */
422 if (remote && !df_conflict_head && head_match && !remote_match) {
423 if (index && !same(index, remote) && !same(index, head))
424 reject_merge(index);
425 return merged_entry(remote, index);
036d51cc 426 }
d723c690 427 /*
ee6566e8
DB
428 * If we have an entry in the index cache, then we want to
429 * make sure that it matches head.
d723c690 430 */
ee6566e8
DB
431 if (index && !same(index, head)) {
432 reject_merge(index);
e6ee623b 433 }
ee6566e8
DB
434
435 if (head) {
436 /* #5ALT, #15 */
437 if (same(head, remote))
438 return merged_entry(head, index);
439 /* #13, #3ALT */
440 if (!df_conflict_remote && remote_match && !head_match)
441 return merged_entry(head, index);
442 }
443
444 /* #1 */
445 if (!head && !remote && any_anc_missing)
446 return 0;
447
448 /* Below are "no merge" cases, which require that the index be
449 * up-to-date to avoid the files getting overwritten with
450 * conflict resolution files.
451 */
452 if (index) {
453 verify_uptodate(index);
454 }
455
456 /* #2, #3, #4, #6, #7, #9, #11. */
d723c690 457 count = 0;
ee6566e8
DB
458 if (!head_match || !remote_match) {
459 for (i = 1; i < head_idx; i++) {
460 if (stages[i]) {
461 keep_entry(stages[i]);
462 count++;
463 break;
464 }
465 }
466 }
4d3fe0c5
JH
467#if DBRT_DEBUG
468 else {
469 fprintf(stderr, "read-tree: warning #16 detected\n");
470 show_stage_entry(stderr, "head ", stages[head_match]);
471 show_stage_entry(stderr, "remote ", stages[remote_match]);
472 }
473#endif
ee6566e8
DB
474 if (head) { count += keep_entry(head); }
475 if (remote) { count += keep_entry(remote); }
d723c690 476 return count;
e6ee623b
LT
477}
478
220a0b52
LT
479/*
480 * Two-way merge.
481 *
c8596009
JH
482 * The rule is to "carry forward" what is in the index without losing
483 * information across a "fast forward", favoring a successful merge
484 * over a merge failure when it makes sense. For details of the
485 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
486 *
220a0b52 487 */
ee6566e8 488static int twoway_merge(struct cache_entry **src)
a3a65234 489{
c8596009
JH
490 struct cache_entry *current = src[0];
491 struct cache_entry *oldtree = src[1], *newtree = src[2];
220a0b52 492
ee6566e8
DB
493 if (merge_size != 2)
494 return error("Cannot do a twoway merge of %d trees\n",
495 merge_size);
e6ee623b 496
c8596009
JH
497 if (current) {
498 if ((!oldtree && !newtree) || /* 4 and 5 */
499 (!oldtree && newtree &&
500 same(current, newtree)) || /* 6 and 7 */
501 (oldtree && newtree &&
502 same(oldtree, newtree)) || /* 14 and 15 */
503 (oldtree && newtree &&
504 !same(oldtree, newtree) && /* 18 and 19*/
505 same(current, newtree))) {
ee6566e8 506 return keep_entry(current);
c8596009
JH
507 }
508 else if (oldtree && !newtree && same(current, oldtree)) {
509 /* 10 or 11 */
ee6566e8 510 return deleted_entry(oldtree, current);
c8596009
JH
511 }
512 else if (oldtree && newtree &&
513 same(current, oldtree) && !same(current, newtree)) {
514 /* 20 or 21 */
ee6566e8 515 return merged_entry(newtree, current);
c8596009 516 }
ee6566e8 517 else {
c8596009 518 /* all other failures */
ee6566e8
DB
519 if (oldtree)
520 reject_merge(oldtree);
521 if (current)
522 reject_merge(current);
523 if (newtree)
524 reject_merge(newtree);
d723c690 525 return -1;
ee6566e8 526 }
e6ee623b 527 }
c8596009 528 else if (newtree)
ee6566e8 529 return merged_entry(newtree, current);
c8596009 530 else
ee6566e8 531 return deleted_entry(oldtree, current);
03efa6d9
JH
532}
533
d723c690
LT
534/*
535 * One-way merge.
536 *
537 * The rule is:
538 * - take the stat information from stage0, take the data from stage1
539 */
ee6566e8 540static int oneway_merge(struct cache_entry **src)
220a0b52 541{
d723c690
LT
542 struct cache_entry *old = src[0];
543 struct cache_entry *a = src[1];
a3a65234 544
ee6566e8
DB
545 if (merge_size != 1)
546 return error("Cannot do a oneway merge of %d trees\n",
547 merge_size);
a3a65234 548
d723c690
LT
549 if (!a)
550 return 0;
b5b42507 551 if (old && same(old, a)) {
ee6566e8 552 return keep_entry(old);
b5b42507 553 }
ee6566e8 554 return merged_entry(a, NULL);
d723c690
LT
555}
556
438195cc
LT
557static int read_cache_unmerged(void)
558{
559 int i, deleted;
560 struct cache_entry **dst;
561
562 read_cache();
563 dst = active_cache;
564 deleted = 0;
565 for (i = 0; i < active_nr; i++) {
566 struct cache_entry *ce = active_cache[i];
567 if (ce_stage(ce)) {
568 deleted++;
569 continue;
570 }
571 if (deleted)
572 *dst = ce;
573 dst++;
574 }
575 active_nr -= deleted;
576 return deleted;
577}
578
4d1f1190 579static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u] <sha1> [<sha2> [<sha3>]])";
c5bac17a 580
96cd5429
JH
581static struct cache_file cache_file;
582
e83c5163
LT
583int main(int argc, char **argv)
584{
ee6566e8 585 int i, newfd, reset, stage = 0;
e83c5163 586 unsigned char sha1[20];
ee6566e8 587 merge_fn_t fn = NULL;
bb233d69 588
96cd5429 589 newfd = hold_index_file_for_update(&cache_file, get_index_file());
83adac3c 590 if (newfd < 0)
2de381f9 591 die("unable to create new cachefile");
83adac3c 592
ca016f0e 593 merge = 0;
438195cc 594 reset = 0;
83adac3c
LT
595 for (i = 1; i < argc; i++) {
596 const char *arg = argv[i];
597
220a0b52
LT
598 /* "-u" means "update", meaning that a merge will update the working directory */
599 if (!strcmp(arg, "-u")) {
600 update = 1;
601 continue;
602 }
603
438195cc
LT
604 /* This differs from "-m" in that we'll silently ignore unmerged entries */
605 if (!strcmp(arg, "--reset")) {
ee6566e8 606 if (stage || merge)
438195cc
LT
607 usage(read_tree_usage);
608 reset = 1;
609 merge = 1;
610 stage = 1;
611 read_cache_unmerged();
7875b50d 612 continue;
438195cc
LT
613 }
614
ee6566e8
DB
615 if (!strcmp(arg, "--head")) {
616 head_idx = stage - 1;
617 fn = threeway_merge;
618 }
619
d99082e0 620 /* "-m" stands for "merge", meaning we start in stage 1 */
83adac3c 621 if (!strcmp(arg, "-m")) {
ee6566e8 622 if (stage || merge)
438195cc
LT
623 usage(read_tree_usage);
624 if (read_cache_unmerged())
625 die("you need to resolve your current index first");
d99082e0 626 stage = 1;
ca016f0e 627 merge = 1;
83adac3c
LT
628 continue;
629 }
03efa6d9 630
3c249c95 631 if (get_sha1(arg, sha1) < 0)
c5bac17a 632 usage(read_tree_usage);
ee6566e8 633 if (list_tree(sha1) < 0)
2de381f9 634 die("failed to unpack tree object %s", arg);
d99082e0 635 stage++;
83adac3c 636 }
a57f0b58
LT
637 if (update && !merge)
638 usage(read_tree_usage);
ee6566e8
DB
639 if (merge && !fn) {
640 if (stage < 2)
a3a65234 641 die("just how do you expect me to merge %d trees?", stage-1);
ee6566e8
DB
642 switch (stage - 1) {
643 case 1:
644 fn = oneway_merge;
645 break;
646 case 2:
647 fn = twoway_merge;
648 break;
649 case 3:
650 fn = threeway_merge;
651 break;
652 default:
653 fn = threeway_merge;
654 break;
03efa6d9 655 }
ca016f0e 656 }
ee6566e8
DB
657
658 if (head_idx < 0) {
659 if (stage - 1 >= 3)
660 head_idx = stage - 2;
661 else
662 head_idx = 1;
663 }
664
665 unpack_trees(fn);
96cd5429
JH
666 if (write_cache(newfd, active_cache, active_nr) ||
667 commit_index_file(&cache_file))
2de381f9 668 die("unable to write new index file");
9614b8dc 669 return 0;
e83c5163 670}