2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
14 static int update = 0;
16 static int head_idx = -1;
17 static int merge_size = 0;
19 static struct object_list *trees = NULL;
21 static struct cache_entry df_conflict_entry = {
24 static struct tree_entry_list df_conflict_list = {
26 .next = &df_conflict_list
29 typedef int (*merge_fn_t)(struct cache_entry **src);
31 static int entcmp(char *name1, int dir1, char *name2, int dir2)
33 int len1 = strlen(name1);
34 int len2 = strlen(name2);
35 int len = len1 < len2 ? len1 : len2;
36 int ret = memcmp(name1, name2, len);
46 ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
52 static int unpack_trees_rec(struct tree_entry_list **posns, int len,
53 const char *base, merge_fn_t fn, int *indpos)
55 int baselen = strlen(base);
56 int src_size = len + 1;
63 struct tree_entry_list **subposns;
64 struct cache_entry **src;
70 /* Find the first name in the input. */
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
94 cache_name = active_cache[*indpos]->name;
95 if (strlen(cache_name) > baselen &&
96 !memcmp(cache_name, base, baselen)) {
97 cache_name += baselen;
106 printf("index %s\n", first);
108 for (i = 0; i < len; i++) {
109 if (!posns[i] || posns[i] == &df_conflict_list)
112 printf("%d %s\n", i + 1, posns[i]->name);
114 if (!first || entcmp(first, firstdir,
116 posns[i]->directory) > 0) {
117 first = posns[i]->name;
118 firstdir = posns[i]->directory;
121 /* No name means we're done */
125 pathlen = strlen(first);
126 ce_size = cache_entry_size(baselen + pathlen);
128 src = xmalloc(sizeof(struct cache_entry *) * src_size);
129 memset(src, 0, sizeof(struct cache_entry *) * src_size);
131 subposns = xmalloc(sizeof(struct tree_list_entry *) * len);
132 memset(subposns, 0, sizeof(struct tree_list_entry *) * len);
134 if (cache_name && !strcmp(cache_name, first)) {
136 src[0] = active_cache[*indpos];
137 remove_cache_entry_at(*indpos);
140 for (i = 0; i < len; i++) {
141 struct cache_entry *ce;
144 (posns[i] != &df_conflict_list &&
145 strcmp(first, posns[i]->name))) {
149 if (posns[i] == &df_conflict_list) {
150 src[i + merge] = &df_conflict_entry;
154 if (posns[i]->directory) {
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;
165 else if (i + 1 < head_idx)
167 else if (i + 1 > head_idx)
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,
177 memcpy(ce->name, base, baselen);
178 memcpy(ce->name + baselen, first, pathlen + 1);
182 memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
184 subposns[i] = &df_conflict_list;
185 posns[i] = posns[i]->next;
192 printf("%s:\n", first);
193 for (i = 0; i < src_size; i++) {
196 printf("%s\n", sha1_to_hex(src[i]->sha1));
204 printf("Added %d entries\n", ret);
208 for (i = 0; i < src_size; i++) {
210 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
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,
231 static void reject_merge(struct cache_entry *ce)
233 die("Entry '%s' would be overwritten by merge. Cannot merge.",
237 static void check_updates(struct cache_entry **src, int nr)
239 static struct checkout state = {
245 unsigned short mask = htons(CE_UPDATE);
247 struct cache_entry *ce = *src++;
253 if (ce->ce_flags & mask) {
254 ce->ce_flags &= ~mask;
256 checkout_entry(ce, &state);
261 static int unpack_trees(merge_fn_t fn)
264 unsigned len = object_list_length(trees);
265 struct tree_entry_list **posns =
266 xmalloc(len * sizeof(struct tree_entry_list *));
268 struct object_list *posn = trees;
270 for (i = 0; i < len; i++) {
271 posns[i] = ((struct tree *) posn->item)->entries;
274 if (unpack_trees_rec(posns, len, "", fn, &indpos))
277 check_updates(active_cache, active_nr);
281 static int list_tree(unsigned char *sha1)
283 struct tree *tree = parse_tree_indirect(sha1);
286 object_list_append(&tree->object, &trees);
290 static int same(struct cache_entry *a, struct cache_entry *b)
296 return a->ce_mode == b->ce_mode &&
297 !memcmp(a->sha1, b->sha1, 20);
302 * When a CE gets turned into an unmerged entry, we
303 * want it to be up-to-date
305 static void verify_uptodate(struct cache_entry *ce)
309 if (!lstat(ce->name, &st)) {
310 unsigned changed = ce_match_stat(ce, &st);
317 die("Entry '%s' not uptodate. Cannot merge.", ce->name);
320 static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
322 merge->ce_flags |= htons(CE_UPDATE);
325 * See if we can re-use the old CE directly?
326 * That way we get the uptodate stat info.
328 * This also removes the UPDATE flag on
331 if (same(old, merge)) {
334 verify_uptodate(old);
337 merge->ce_flags &= ~htons(CE_STAGEMASK);
338 add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
342 static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
345 verify_uptodate(old);
347 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
351 static int keep_entry(struct cache_entry *ce)
353 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
358 static void show_stage_entry(FILE *o,
359 const char *label, const struct cache_entry *ce)
361 fprintf(stderr, "%s%06o %s %d\t%s\n",
364 sha1_to_hex(ce->sha1),
370 static int threeway_merge(struct cache_entry **stages)
372 struct cache_entry *index;
373 struct cache_entry *head;
374 struct cache_entry *remote = stages[head_idx + 1];
377 int remote_match = 0;
379 int df_conflict_head = 0;
380 int df_conflict_remote = 0;
382 int any_anc_missing = 0;
385 for (i = 1; i < head_idx; i++) {
391 head = stages[head_idx];
393 if (head == &df_conflict_entry) {
394 df_conflict_head = 1;
398 if (remote == &df_conflict_entry) {
399 df_conflict_remote = 1;
403 /* First, if there's a #16 situation, note that to prevent #13
406 if (!same(remote, head)) {
407 for (i = 1; i < head_idx; i++) {
408 if (same(stages[i], head)) {
411 if (same(stages[i], remote)) {
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.
421 /* #14, #14ALT, #2ALT */
422 if (remote && !df_conflict_head && head_match && !remote_match) {
423 if (index && !same(index, remote) && !same(index, head))
425 return merged_entry(remote, index);
428 * If we have an entry in the index cache, then we want to
429 * make sure that it matches head.
431 if (index && !same(index, head)) {
437 if (same(head, remote))
438 return merged_entry(head, index);
440 if (!df_conflict_remote && remote_match && !head_match)
441 return merged_entry(head, index);
445 if (!head && !remote && any_anc_missing)
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.
453 verify_uptodate(index);
456 /* #2, #3, #4, #6, #7, #9, #11. */
458 if (!head_match || !remote_match) {
459 for (i = 1; i < head_idx; i++) {
461 keep_entry(stages[i]);
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]);
474 if (head) { count += keep_entry(head); }
475 if (remote) { count += keep_entry(remote); }
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>.
488 static int twoway_merge(struct cache_entry **src)
490 struct cache_entry *current = src[0];
491 struct cache_entry *oldtree = src[1], *newtree = src[2];
494 return error("Cannot do a twoway merge of %d trees\n",
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))) {
506 return keep_entry(current);
508 else if (oldtree && !newtree && same(current, oldtree)) {
510 return deleted_entry(oldtree, current);
512 else if (oldtree && newtree &&
513 same(current, oldtree) && !same(current, newtree)) {
515 return merged_entry(newtree, current);
518 /* all other failures */
520 reject_merge(oldtree);
522 reject_merge(current);
524 reject_merge(newtree);
529 return merged_entry(newtree, current);
531 return deleted_entry(oldtree, current);
538 * - take the stat information from stage0, take the data from stage1
540 static int oneway_merge(struct cache_entry **src)
542 struct cache_entry *old = src[0];
543 struct cache_entry *a = src[1];
546 return error("Cannot do a oneway merge of %d trees\n",
551 if (old && same(old, a)) {
552 return keep_entry(old);
554 return merged_entry(a, NULL);
557 static int read_cache_unmerged(void)
560 struct cache_entry **dst;
565 for (i = 0; i < active_nr; i++) {
566 struct cache_entry *ce = active_cache[i];
575 active_nr -= deleted;
579 static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u] <sha1> [<sha2> [<sha3>]])";
581 static struct cache_file cache_file;
583 int main(int argc, char **argv)
585 int i, newfd, reset, stage = 0;
586 unsigned char sha1[20];
587 merge_fn_t fn = NULL;
589 newfd = hold_index_file_for_update(&cache_file, get_index_file());
591 die("unable to create new cachefile");
595 for (i = 1; i < argc; i++) {
596 const char *arg = argv[i];
598 /* "-u" means "update", meaning that a merge will update the working directory */
599 if (!strcmp(arg, "-u")) {
604 /* This differs from "-m" in that we'll silently ignore unmerged entries */
605 if (!strcmp(arg, "--reset")) {
607 usage(read_tree_usage);
611 read_cache_unmerged();
615 if (!strcmp(arg, "--head")) {
616 head_idx = stage - 1;
620 /* "-m" stands for "merge", meaning we start in stage 1 */
621 if (!strcmp(arg, "-m")) {
623 usage(read_tree_usage);
624 if (read_cache_unmerged())
625 die("you need to resolve your current index first");
631 if (get_sha1(arg, sha1) < 0)
632 usage(read_tree_usage);
633 if (list_tree(sha1) < 0)
634 die("failed to unpack tree object %s", arg);
637 if (update && !merge)
638 usage(read_tree_usage);
641 die("just how do you expect me to merge %d trees?", stage-1);
660 head_idx = stage - 2;
666 if (write_cache(newfd, active_cache, active_nr) ||
667 commit_index_file(&cache_file))
668 die("unable to write new index file");