Windows: boost startup by avoiding a static dependency on shell32.dll
[git/dscho.git] / unpack-trees.c
blobacdd3117370e596716a0bdb751d6255690e6c700
1 #define NO_THE_INDEX_COMPATIBILITY_MACROS
2 #include "cache.h"
3 #include "dir.h"
4 #include "tree.h"
5 #include "tree-walk.h"
6 #include "cache-tree.h"
7 #include "unpack-trees.h"
8 #include "progress.h"
9 #include "refs.h"
10 #include "attr.h"
13  * Error messages expected by scripts out of plumbing commands such as
14  * read-tree.  Non-scripted Porcelain is not required to use these messages
15  * and in fact are encouraged to reword them to better suit their particular
16  * situation better.  See how "git checkout" replaces not_uptodate_file to
17  * explain why it does not allow switching between branches when you have
18  * local changes, for example.
19  */
20 static struct unpack_trees_error_msgs unpack_plumbing_errors = {
21         /* would_overwrite */
22         "Entry '%s' would be overwritten by merge. Cannot merge.",
24         /* not_uptodate_file */
25         "Entry '%s' not uptodate. Cannot merge.",
27         /* not_uptodate_dir */
28         "Updating '%s' would lose untracked files in it",
30         /* would_lose_untracked */
31         "Untracked working tree file '%s' would be %s by merge.",
33         /* bind_overlap */
34         "Entry '%s' overlaps with '%s'.  Cannot bind.",
36         /* sparse_not_uptodate_file */
37         "Entry '%s' not uptodate. Cannot update sparse checkout.",
39         /* would_lose_orphaned */
40         "Working tree file '%s' would be %s by sparse checkout update.",
43 #define ERRORMSG(o,fld) \
44         ( ((o) && (o)->msgs.fld) \
45         ? ((o)->msgs.fld) \
46         : (unpack_plumbing_errors.fld) )
48 static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
49         unsigned int set, unsigned int clear)
51         unsigned int size = ce_size(ce);
52         struct cache_entry *new = xmalloc(size);
54         clear |= CE_HASHED | CE_UNHASHED;
56         memcpy(new, ce, size);
57         new->next = NULL;
58         new->ce_flags = (new->ce_flags & ~clear) | set;
59         add_index_entry(&o->result, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
63  * Unlink the last component and schedule the leading directories for
64  * removal, such that empty directories get removed.
65  */
66 static void unlink_entry(struct cache_entry *ce)
68         if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
69                 return;
70         if (unlink_or_warn(ce->name))
71                 return;
72         schedule_dir_for_removal(ce->name, ce_namelen(ce));
75 static struct checkout state;
76 static int check_updates(struct unpack_trees_options *o)
78         unsigned cnt = 0, total = 0;
79         struct progress *progress = NULL;
80         struct index_state *index = &o->result;
81         int i;
82         int errs = 0;
84         if (o->update && o->verbose_update) {
85                 for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
86                         struct cache_entry *ce = index->cache[cnt];
87                         if (ce->ce_flags & (CE_UPDATE | CE_REMOVE | CE_WT_REMOVE))
88                                 total++;
89                 }
91                 progress = start_progress_delay("Checking out files",
92                                                 total, 50, 1);
93                 cnt = 0;
94         }
96         if (o->update)
97                 git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
98         for (i = 0; i < index->cache_nr; i++) {
99                 struct cache_entry *ce = index->cache[i];
101                 if (ce->ce_flags & CE_WT_REMOVE) {
102                         display_progress(progress, ++cnt);
103                         if (o->update)
104                                 unlink_entry(ce);
105                         continue;
106                 }
108                 if (ce->ce_flags & CE_REMOVE) {
109                         display_progress(progress, ++cnt);
110                         if (o->update)
111                                 unlink_entry(ce);
112                 }
113         }
114         remove_marked_cache_entries(&o->result);
115         remove_scheduled_dirs();
117         for (i = 0; i < index->cache_nr; i++) {
118                 struct cache_entry *ce = index->cache[i];
120                 if (ce->ce_flags & CE_UPDATE) {
121                         display_progress(progress, ++cnt);
122                         ce->ce_flags &= ~CE_UPDATE;
123                         if (o->update) {
124                                 errs |= checkout_entry(ce, &state, NULL);
125                         }
126                 }
127         }
128         stop_progress(&progress);
129         if (o->update)
130                 git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
131         return errs != 0;
134 static int verify_uptodate_sparse(struct cache_entry *ce, struct unpack_trees_options *o);
135 static int verify_absent_sparse(struct cache_entry *ce, const char *action, struct unpack_trees_options *o);
137 static int will_have_skip_worktree(const struct cache_entry *ce, struct unpack_trees_options *o)
139         const char *basename;
141         if (ce_stage(ce))
142                 return 0;
144         basename = strrchr(ce->name, '/');
145         basename = basename ? basename+1 : ce->name;
146         return excluded_from_list(ce->name, ce_namelen(ce), basename, NULL, o->el) <= 0;
149 static int apply_sparse_checkout(struct cache_entry *ce, struct unpack_trees_options *o)
151         int was_skip_worktree = ce_skip_worktree(ce);
153         if (will_have_skip_worktree(ce, o))
154                 ce->ce_flags |= CE_SKIP_WORKTREE;
155         else
156                 ce->ce_flags &= ~CE_SKIP_WORKTREE;
158         /*
159          * We only care about files getting into the checkout area
160          * If merge strategies want to remove some, go ahead, this
161          * flag will be removed eventually in unpack_trees() if it's
162          * outside checkout area.
163          */
164         if (ce->ce_flags & CE_REMOVE)
165                 return 0;
167         if (!was_skip_worktree && ce_skip_worktree(ce)) {
168                 /*
169                  * If CE_UPDATE is set, verify_uptodate() must be called already
170                  * also stat info may have lost after merged_entry() so calling
171                  * verify_uptodate() again may fail
172                  */
173                 if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
174                         return -1;
175                 ce->ce_flags |= CE_WT_REMOVE;
176         }
177         if (was_skip_worktree && !ce_skip_worktree(ce)) {
178                 if (verify_absent_sparse(ce, "overwritten", o))
179                         return -1;
180                 ce->ce_flags |= CE_UPDATE;
181         }
182         return 0;
185 static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_options *o)
187         int ret = o->fn(src, o);
188         if (ret > 0)
189                 ret = 0;
190         return ret;
193 static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
195         struct cache_entry *src[5] = { ce, NULL, };
197         o->pos++;
198         if (ce_stage(ce)) {
199                 if (o->skip_unmerged) {
200                         add_entry(o, ce, 0, 0);
201                         return 0;
202                 }
203         }
204         return call_unpack_fn(src, o);
207 static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
209         int i;
210         struct tree_desc t[MAX_UNPACK_TREES];
211         struct traverse_info newinfo;
212         struct name_entry *p;
214         p = names;
215         while (!p->mode)
216                 p++;
218         newinfo = *info;
219         newinfo.prev = info;
220         newinfo.name = *p;
221         newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
222         newinfo.conflicts |= df_conflicts;
224         for (i = 0; i < n; i++, dirmask >>= 1) {
225                 const unsigned char *sha1 = NULL;
226                 if (dirmask & 1)
227                         sha1 = names[i].sha1;
228                 fill_tree_descriptor(t+i, sha1);
229         }
230         return traverse_trees(n, t, &newinfo);
234  * Compare the traverse-path to the cache entry without actually
235  * having to generate the textual representation of the traverse
236  * path.
238  * NOTE! This *only* compares up to the size of the traverse path
239  * itself - the caller needs to do the final check for the cache
240  * entry having more data at the end!
241  */
242 static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
244         int len, pathlen, ce_len;
245         const char *ce_name;
247         if (info->prev) {
248                 int cmp = do_compare_entry(ce, info->prev, &info->name);
249                 if (cmp)
250                         return cmp;
251         }
252         pathlen = info->pathlen;
253         ce_len = ce_namelen(ce);
255         /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
256         if (ce_len < pathlen)
257                 return -1;
259         ce_len -= pathlen;
260         ce_name = ce->name + pathlen;
262         len = tree_entry_len(n->path, n->sha1);
263         return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
266 static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
268         int cmp = do_compare_entry(ce, info, n);
269         if (cmp)
270                 return cmp;
272         /*
273          * Even if the beginning compared identically, the ce should
274          * compare as bigger than a directory leading up to it!
275          */
276         return ce_namelen(ce) > traverse_path_len(info, n);
279 static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
281         int len = traverse_path_len(info, n);
282         struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
284         ce->ce_mode = create_ce_mode(n->mode);
285         ce->ce_flags = create_ce_flags(len, stage);
286         hashcpy(ce->sha1, n->sha1);
287         make_traverse_path(ce->name, info, n);
289         return ce;
292 static int unpack_nondirectories(int n, unsigned long mask,
293                                  unsigned long dirmask,
294                                  struct cache_entry **src,
295                                  const struct name_entry *names,
296                                  const struct traverse_info *info)
298         int i;
299         struct unpack_trees_options *o = info->data;
300         unsigned long conflicts;
302         /* Do we have *only* directories? Nothing to do */
303         if (mask == dirmask && !src[0])
304                 return 0;
306         conflicts = info->conflicts;
307         if (o->merge)
308                 conflicts >>= 1;
309         conflicts |= dirmask;
311         /*
312          * Ok, we've filled in up to any potential index entry in src[0],
313          * now do the rest.
314          */
315         for (i = 0; i < n; i++) {
316                 int stage;
317                 unsigned int bit = 1ul << i;
318                 if (conflicts & bit) {
319                         src[i + o->merge] = o->df_conflict_entry;
320                         continue;
321                 }
322                 if (!(mask & bit))
323                         continue;
324                 if (!o->merge)
325                         stage = 0;
326                 else if (i + 1 < o->head_idx)
327                         stage = 1;
328                 else if (i + 1 > o->head_idx)
329                         stage = 3;
330                 else
331                         stage = 2;
332                 src[i + o->merge] = create_ce_entry(info, names + i, stage);
333         }
335         if (o->merge)
336                 return call_unpack_fn(src, o);
338         for (i = 0; i < n; i++)
339                 if (src[i] && src[i] != o->df_conflict_entry)
340                         add_entry(o, src[i], 0, 0);
341         return 0;
344 static int unpack_failed(struct unpack_trees_options *o, const char *message)
346         discard_index(&o->result);
347         if (!o->gently) {
348                 if (message)
349                         return error("%s", message);
350                 return -1;
351         }
352         return -1;
355 static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
357         struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
358         struct unpack_trees_options *o = info->data;
359         const struct name_entry *p = names;
361         /* Find first entry with a real name (we could use "mask" too) */
362         while (!p->mode)
363                 p++;
365         /* Are we supposed to look at the index too? */
366         if (o->merge) {
367                 while (o->pos < o->src_index->cache_nr) {
368                         struct cache_entry *ce = o->src_index->cache[o->pos];
369                         int cmp = compare_entry(ce, info, p);
370                         if (cmp < 0) {
371                                 if (unpack_index_entry(ce, o) < 0)
372                                         return unpack_failed(o, NULL);
373                                 continue;
374                         }
375                         if (!cmp) {
376                                 o->pos++;
377                                 if (ce_stage(ce)) {
378                                         /*
379                                          * If we skip unmerged index entries, we'll skip this
380                                          * entry *and* the tree entries associated with it!
381                                          */
382                                         if (o->skip_unmerged) {
383                                                 add_entry(o, ce, 0, 0);
384                                                 return mask;
385                                         }
386                                 }
387                                 src[0] = ce;
388                         }
389                         break;
390                 }
391         }
393         if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
394                 return -1;
396         /* Now handle any directories.. */
397         if (dirmask) {
398                 unsigned long conflicts = mask & ~dirmask;
399                 if (o->merge) {
400                         conflicts <<= 1;
401                         if (src[0])
402                                 conflicts |= 1;
403                 }
405                 /* special case: "diff-index --cached" looking at a tree */
406                 if (o->diff_index_cached &&
407                     n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
408                         int matches;
409                         matches = cache_tree_matches_traversal(o->src_index->cache_tree,
410                                                                names, info);
411                         /*
412                          * Everything under the name matches.  Adjust o->pos to
413                          * skip the entire hierarchy.
414                          */
415                         if (matches) {
416                                 o->pos += matches;
417                                 return mask;
418                         }
419                 }
421                 if (traverse_trees_recursive(n, dirmask, conflicts,
422                                              names, info) < 0)
423                         return -1;
424                 return mask;
425         }
427         return mask;
431  * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
432  * resulting index, -2 on failure to reflect the changes to the work tree.
433  */
434 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
436         int i, ret;
437         static struct cache_entry *dfc;
438         struct exclude_list el;
440         if (len > MAX_UNPACK_TREES)
441                 die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
442         memset(&state, 0, sizeof(state));
443         state.base_dir = "";
444         state.force = 1;
445         state.quiet = 1;
446         state.refresh_cache = 1;
448         memset(&el, 0, sizeof(el));
449         if (!core_apply_sparse_checkout || !o->update)
450                 o->skip_sparse_checkout = 1;
451         if (!o->skip_sparse_checkout) {
452                 if (add_excludes_from_file_to_list(git_path("info/sparse-checkout"), "", 0, NULL, &el, 0) < 0)
453                         o->skip_sparse_checkout = 1;
454                 else
455                         o->el = &el;
456         }
458         memset(&o->result, 0, sizeof(o->result));
459         o->result.initialized = 1;
460         if (o->src_index) {
461                 o->result.timestamp.sec = o->src_index->timestamp.sec;
462                 o->result.timestamp.nsec = o->src_index->timestamp.nsec;
463         }
464         o->merge_size = len;
466         if (!dfc)
467                 dfc = xcalloc(1, cache_entry_size(0));
468         o->df_conflict_entry = dfc;
470         if (len) {
471                 const char *prefix = o->prefix ? o->prefix : "";
472                 struct traverse_info info;
474                 setup_traverse_info(&info, prefix);
475                 info.fn = unpack_callback;
476                 info.data = o;
478                 if (traverse_trees(len, t, &info) < 0) {
479                         ret = unpack_failed(o, NULL);
480                         goto done;
481                 }
482         }
484         /* Any left-over entries in the index? */
485         if (o->merge) {
486                 while (o->pos < o->src_index->cache_nr) {
487                         struct cache_entry *ce = o->src_index->cache[o->pos];
488                         if (unpack_index_entry(ce, o) < 0) {
489                                 ret = unpack_failed(o, NULL);
490                                 goto done;
491                         }
492                 }
493         }
495         if (o->trivial_merges_only && o->nontrivial_merge) {
496                 ret = unpack_failed(o, "Merge requires file-level merging");
497                 goto done;
498         }
500         if (!o->skip_sparse_checkout) {
501                 int empty_worktree = 1;
502                 for (i = 0;i < o->result.cache_nr;i++) {
503                         struct cache_entry *ce = o->result.cache[i];
505                         if (apply_sparse_checkout(ce, o)) {
506                                 ret = -1;
507                                 goto done;
508                         }
509                         /*
510                          * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
511                          * area as a result of ce_skip_worktree() shortcuts in
512                          * verify_absent() and verify_uptodate(). Clear them.
513                          */
514                         if (ce_skip_worktree(ce))
515                                 ce->ce_flags &= ~(CE_UPDATE | CE_REMOVE);
516                         else
517                                 empty_worktree = 0;
519                 }
520                 if (o->result.cache_nr && empty_worktree) {
521                         ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
522                         goto done;
523                 }
524         }
526         o->src_index = NULL;
527         ret = check_updates(o) ? (-2) : 0;
528         if (o->dst_index)
529                 *o->dst_index = o->result;
531 done:
532         for (i = 0;i < el.nr;i++)
533                 free(el.excludes[i]);
534         if (el.excludes)
535                 free(el.excludes);
537         return ret;
540 /* Here come the merge functions */
542 static int reject_merge(struct cache_entry *ce, struct unpack_trees_options *o)
544         return error(ERRORMSG(o, would_overwrite), ce->name);
547 static int same(struct cache_entry *a, struct cache_entry *b)
549         if (!!a != !!b)
550                 return 0;
551         if (!a && !b)
552                 return 1;
553         if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
554                 return 0;
555         return a->ce_mode == b->ce_mode &&
556                !hashcmp(a->sha1, b->sha1);
561  * When a CE gets turned into an unmerged entry, we
562  * want it to be up-to-date
563  */
564 static int verify_uptodate_1(struct cache_entry *ce,
565                                    struct unpack_trees_options *o,
566                                    const char *error_msg)
568         struct stat st;
570         if (o->index_only || (!ce_skip_worktree(ce) && (o->reset || ce_uptodate(ce))))
571                 return 0;
573         if (!lstat(ce->name, &st)) {
574                 unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
575                 if (!changed)
576                         return 0;
577                 /*
578                  * NEEDSWORK: the current default policy is to allow
579                  * submodule to be out of sync wrt the supermodule
580                  * index.  This needs to be tightened later for
581                  * submodules that are marked to be automatically
582                  * checked out.
583                  */
584                 if (S_ISGITLINK(ce->ce_mode))
585                         return 0;
586                 errno = 0;
587         }
588         if (errno == ENOENT)
589                 return 0;
590         return o->gently ? -1 :
591                 error(error_msg, ce->name);
594 static int verify_uptodate(struct cache_entry *ce,
595                            struct unpack_trees_options *o)
597         if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
598                 return 0;
599         return verify_uptodate_1(ce, o, ERRORMSG(o, not_uptodate_file));
602 static int verify_uptodate_sparse(struct cache_entry *ce,
603                                   struct unpack_trees_options *o)
605         return verify_uptodate_1(ce, o, ERRORMSG(o, sparse_not_uptodate_file));
608 static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
610         if (ce)
611                 cache_tree_invalidate_path(o->src_index->cache_tree, ce->name);
615  * Check that checking out ce->sha1 in subdir ce->name is not
616  * going to overwrite any working files.
618  * Currently, git does not checkout subprojects during a superproject
619  * checkout, so it is not going to overwrite anything.
620  */
621 static int verify_clean_submodule(struct cache_entry *ce, const char *action,
622                                       struct unpack_trees_options *o)
624         return 0;
627 static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
628                                       struct unpack_trees_options *o)
630         /*
631          * we are about to extract "ce->name"; we would not want to lose
632          * anything in the existing directory there.
633          */
634         int namelen;
635         int i;
636         struct dir_struct d;
637         char *pathbuf;
638         int cnt = 0;
639         unsigned char sha1[20];
641         if (S_ISGITLINK(ce->ce_mode) &&
642             resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
643                 /* If we are not going to update the submodule, then
644                  * we don't care.
645                  */
646                 if (!hashcmp(sha1, ce->sha1))
647                         return 0;
648                 return verify_clean_submodule(ce, action, o);
649         }
651         /*
652          * First let's make sure we do not have a local modification
653          * in that directory.
654          */
655         namelen = strlen(ce->name);
656         for (i = o->pos; i < o->src_index->cache_nr; i++) {
657                 struct cache_entry *ce2 = o->src_index->cache[i];
658                 int len = ce_namelen(ce2);
659                 if (len < namelen ||
660                     strncmp(ce->name, ce2->name, namelen) ||
661                     ce2->name[namelen] != '/')
662                         break;
663                 /*
664                  * ce2->name is an entry in the subdirectory.
665                  */
666                 if (!ce_stage(ce2)) {
667                         if (verify_uptodate(ce2, o))
668                                 return -1;
669                         add_entry(o, ce2, CE_REMOVE, 0);
670                 }
671                 cnt++;
672         }
674         /*
675          * Then we need to make sure that we do not lose a locally
676          * present file that is not ignored.
677          */
678         pathbuf = xmalloc(namelen + 2);
679         memcpy(pathbuf, ce->name, namelen);
680         strcpy(pathbuf+namelen, "/");
682         memset(&d, 0, sizeof(d));
683         if (o->dir)
684                 d.exclude_per_dir = o->dir->exclude_per_dir;
685         i = read_directory(&d, pathbuf, namelen+1, NULL);
686         if (i)
687                 return o->gently ? -1 :
688                         error(ERRORMSG(o, not_uptodate_dir), ce->name);
689         free(pathbuf);
690         return cnt;
694  * This gets called when there was no index entry for the tree entry 'dst',
695  * but we found a file in the working tree that 'lstat()' said was fine,
696  * and we're on a case-insensitive filesystem.
698  * See if we can find a case-insensitive match in the index that also
699  * matches the stat information, and assume it's that other file!
700  */
701 static int icase_exists(struct unpack_trees_options *o, struct cache_entry *dst, struct stat *st)
703         struct cache_entry *src;
705         src = index_name_exists(o->src_index, dst->name, ce_namelen(dst), 1);
706         return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
710  * We do not want to remove or overwrite a working tree file that
711  * is not tracked, unless it is ignored.
712  */
713 static int verify_absent_1(struct cache_entry *ce, const char *action,
714                                  struct unpack_trees_options *o,
715                                  const char *error_msg)
717         struct stat st;
719         if (o->index_only || o->reset || !o->update)
720                 return 0;
722         if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
723                 return 0;
725         if (!lstat(ce->name, &st)) {
726                 int ret;
727                 int dtype = ce_to_dtype(ce);
728                 struct cache_entry *result;
730                 /*
731                  * It may be that the 'lstat()' succeeded even though
732                  * target 'ce' was absent, because there is an old
733                  * entry that is different only in case..
734                  *
735                  * Ignore that lstat() if it matches.
736                  */
737                 if (ignore_case && icase_exists(o, ce, &st))
738                         return 0;
740                 if (o->dir && excluded(o->dir, ce->name, &dtype))
741                         /*
742                          * ce->name is explicitly excluded, so it is Ok to
743                          * overwrite it.
744                          */
745                         return 0;
746                 if (S_ISDIR(st.st_mode)) {
747                         /*
748                          * We are checking out path "foo" and
749                          * found "foo/." in the working tree.
750                          * This is tricky -- if we have modified
751                          * files that are in "foo/" we would lose
752                          * them.
753                          */
754                         ret = verify_clean_subdirectory(ce, action, o);
755                         if (ret < 0)
756                                 return ret;
758                         /*
759                          * If this removed entries from the index,
760                          * what that means is:
761                          *
762                          * (1) the caller unpack_callback() saw path/foo
763                          * in the index, and it has not removed it because
764                          * it thinks it is handling 'path' as blob with
765                          * D/F conflict;
766                          * (2) we will return "ok, we placed a merged entry
767                          * in the index" which would cause o->pos to be
768                          * incremented by one;
769                          * (3) however, original o->pos now has 'path/foo'
770                          * marked with "to be removed".
771                          *
772                          * We need to increment it by the number of
773                          * deleted entries here.
774                          */
775                         o->pos += ret;
776                         return 0;
777                 }
779                 /*
780                  * The previous round may already have decided to
781                  * delete this path, which is in a subdirectory that
782                  * is being replaced with a blob.
783                  */
784                 result = index_name_exists(&o->result, ce->name, ce_namelen(ce), 0);
785                 if (result) {
786                         if (result->ce_flags & CE_REMOVE)
787                                 return 0;
788                 }
790                 return o->gently ? -1 :
791                         error(ERRORMSG(o, would_lose_untracked), ce->name, action);
792         }
793         return 0;
795 static int verify_absent(struct cache_entry *ce, const char *action,
796                          struct unpack_trees_options *o)
798         if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
799                 return 0;
800         return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_untracked));
803 static int verify_absent_sparse(struct cache_entry *ce, const char *action,
804                          struct unpack_trees_options *o)
806         return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_orphaned));
809 static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
810                 struct unpack_trees_options *o)
812         int update = CE_UPDATE;
814         if (!old) {
815                 if (verify_absent(merge, "overwritten", o))
816                         return -1;
817                 invalidate_ce_path(merge, o);
818         } else if (!(old->ce_flags & CE_CONFLICTED)) {
819                 /*
820                  * See if we can re-use the old CE directly?
821                  * That way we get the uptodate stat info.
822                  *
823                  * This also removes the UPDATE flag on a match; otherwise
824                  * we will end up overwriting local changes in the work tree.
825                  */
826                 if (same(old, merge)) {
827                         copy_cache_entry(merge, old);
828                         update = 0;
829                 } else {
830                         if (verify_uptodate(old, o))
831                                 return -1;
832                         if (ce_skip_worktree(old))
833                                 update |= CE_SKIP_WORKTREE;
834                         invalidate_ce_path(old, o);
835                 }
836         } else {
837                 /*
838                  * Previously unmerged entry left as an existence
839                  * marker by read_index_unmerged();
840                  */
841                 invalidate_ce_path(old, o);
842         }
844         add_entry(o, merge, update, CE_STAGEMASK);
845         return 1;
848 static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
849                 struct unpack_trees_options *o)
851         /* Did it exist in the index? */
852         if (!old) {
853                 if (verify_absent(ce, "removed", o))
854                         return -1;
855                 return 0;
856         }
857         if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
858                 return -1;
859         add_entry(o, ce, CE_REMOVE, 0);
860         invalidate_ce_path(ce, o);
861         return 1;
864 static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
866         add_entry(o, ce, 0, 0);
867         return 1;
870 #if DBRT_DEBUG
871 static void show_stage_entry(FILE *o,
872                              const char *label, const struct cache_entry *ce)
874         if (!ce)
875                 fprintf(o, "%s (missing)\n", label);
876         else
877                 fprintf(o, "%s%06o %s %d\t%s\n",
878                         label,
879                         ce->ce_mode,
880                         sha1_to_hex(ce->sha1),
881                         ce_stage(ce),
882                         ce->name);
884 #endif
886 int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
888         struct cache_entry *index;
889         struct cache_entry *head;
890         struct cache_entry *remote = stages[o->head_idx + 1];
891         int count;
892         int head_match = 0;
893         int remote_match = 0;
895         int df_conflict_head = 0;
896         int df_conflict_remote = 0;
898         int any_anc_missing = 0;
899         int no_anc_exists = 1;
900         int i;
902         for (i = 1; i < o->head_idx; i++) {
903                 if (!stages[i] || stages[i] == o->df_conflict_entry)
904                         any_anc_missing = 1;
905                 else
906                         no_anc_exists = 0;
907         }
909         index = stages[0];
910         head = stages[o->head_idx];
912         if (head == o->df_conflict_entry) {
913                 df_conflict_head = 1;
914                 head = NULL;
915         }
917         if (remote == o->df_conflict_entry) {
918                 df_conflict_remote = 1;
919                 remote = NULL;
920         }
922         /* First, if there's a #16 situation, note that to prevent #13
923          * and #14.
924          */
925         if (!same(remote, head)) {
926                 for (i = 1; i < o->head_idx; i++) {
927                         if (same(stages[i], head)) {
928                                 head_match = i;
929                         }
930                         if (same(stages[i], remote)) {
931                                 remote_match = i;
932                         }
933                 }
934         }
936         /* We start with cases where the index is allowed to match
937          * something other than the head: #14(ALT) and #2ALT, where it
938          * is permitted to match the result instead.
939          */
940         /* #14, #14ALT, #2ALT */
941         if (remote && !df_conflict_head && head_match && !remote_match) {
942                 if (index && !same(index, remote) && !same(index, head))
943                         return o->gently ? -1 : reject_merge(index, o);
944                 return merged_entry(remote, index, o);
945         }
946         /*
947          * If we have an entry in the index cache, then we want to
948          * make sure that it matches head.
949          */
950         if (index && !same(index, head))
951                 return o->gently ? -1 : reject_merge(index, o);
953         if (head) {
954                 /* #5ALT, #15 */
955                 if (same(head, remote))
956                         return merged_entry(head, index, o);
957                 /* #13, #3ALT */
958                 if (!df_conflict_remote && remote_match && !head_match)
959                         return merged_entry(head, index, o);
960         }
962         /* #1 */
963         if (!head && !remote && any_anc_missing)
964                 return 0;
966         /* Under the new "aggressive" rule, we resolve mostly trivial
967          * cases that we historically had git-merge-one-file resolve.
968          */
969         if (o->aggressive) {
970                 int head_deleted = !head && !df_conflict_head;
971                 int remote_deleted = !remote && !df_conflict_remote;
972                 struct cache_entry *ce = NULL;
974                 if (index)
975                         ce = index;
976                 else if (head)
977                         ce = head;
978                 else if (remote)
979                         ce = remote;
980                 else {
981                         for (i = 1; i < o->head_idx; i++) {
982                                 if (stages[i] && stages[i] != o->df_conflict_entry) {
983                                         ce = stages[i];
984                                         break;
985                                 }
986                         }
987                 }
989                 /*
990                  * Deleted in both.
991                  * Deleted in one and unchanged in the other.
992                  */
993                 if ((head_deleted && remote_deleted) ||
994                     (head_deleted && remote && remote_match) ||
995                     (remote_deleted && head && head_match)) {
996                         if (index)
997                                 return deleted_entry(index, index, o);
998                         if (ce && !head_deleted) {
999                                 if (verify_absent(ce, "removed", o))
1000                                         return -1;
1001                         }
1002                         return 0;
1003                 }
1004                 /*
1005                  * Added in both, identically.
1006                  */
1007                 if (no_anc_exists && head && remote && same(head, remote))
1008                         return merged_entry(head, index, o);
1010         }
1012         /* Below are "no merge" cases, which require that the index be
1013          * up-to-date to avoid the files getting overwritten with
1014          * conflict resolution files.
1015          */
1016         if (index) {
1017                 if (verify_uptodate(index, o))
1018                         return -1;
1019         }
1021         o->nontrivial_merge = 1;
1023         /* #2, #3, #4, #6, #7, #9, #10, #11. */
1024         count = 0;
1025         if (!head_match || !remote_match) {
1026                 for (i = 1; i < o->head_idx; i++) {
1027                         if (stages[i] && stages[i] != o->df_conflict_entry) {
1028                                 keep_entry(stages[i], o);
1029                                 count++;
1030                                 break;
1031                         }
1032                 }
1033         }
1034 #if DBRT_DEBUG
1035         else {
1036                 fprintf(stderr, "read-tree: warning #16 detected\n");
1037                 show_stage_entry(stderr, "head   ", stages[head_match]);
1038                 show_stage_entry(stderr, "remote ", stages[remote_match]);
1039         }
1040 #endif
1041         if (head) { count += keep_entry(head, o); }
1042         if (remote) { count += keep_entry(remote, o); }
1043         return count;
1047  * Two-way merge.
1049  * The rule is to "carry forward" what is in the index without losing
1050  * information across a "fast-forward", favoring a successful merge
1051  * over a merge failure when it makes sense.  For details of the
1052  * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1054  */
1055 int twoway_merge(struct cache_entry **src, struct unpack_trees_options *o)
1057         struct cache_entry *current = src[0];
1058         struct cache_entry *oldtree = src[1];
1059         struct cache_entry *newtree = src[2];
1061         if (o->merge_size != 2)
1062                 return error("Cannot do a twoway merge of %d trees",
1063                              o->merge_size);
1065         if (oldtree == o->df_conflict_entry)
1066                 oldtree = NULL;
1067         if (newtree == o->df_conflict_entry)
1068                 newtree = NULL;
1070         if (current) {
1071                 if ((!oldtree && !newtree) || /* 4 and 5 */
1072                     (!oldtree && newtree &&
1073                      same(current, newtree)) || /* 6 and 7 */
1074                     (oldtree && newtree &&
1075                      same(oldtree, newtree)) || /* 14 and 15 */
1076                     (oldtree && newtree &&
1077                      !same(oldtree, newtree) && /* 18 and 19 */
1078                      same(current, newtree))) {
1079                         return keep_entry(current, o);
1080                 }
1081                 else if (oldtree && !newtree && same(current, oldtree)) {
1082                         /* 10 or 11 */
1083                         return deleted_entry(oldtree, current, o);
1084                 }
1085                 else if (oldtree && newtree &&
1086                          same(current, oldtree) && !same(current, newtree)) {
1087                         /* 20 or 21 */
1088                         return merged_entry(newtree, current, o);
1089                 }
1090                 else {
1091                         /* all other failures */
1092                         if (oldtree)
1093                                 return o->gently ? -1 : reject_merge(oldtree, o);
1094                         if (current)
1095                                 return o->gently ? -1 : reject_merge(current, o);
1096                         if (newtree)
1097                                 return o->gently ? -1 : reject_merge(newtree, o);
1098                         return -1;
1099                 }
1100         }
1101         else if (newtree) {
1102                 if (oldtree && !o->initial_checkout) {
1103                         /*
1104                          * deletion of the path was staged;
1105                          */
1106                         if (same(oldtree, newtree))
1107                                 return 1;
1108                         return reject_merge(oldtree, o);
1109                 }
1110                 return merged_entry(newtree, current, o);
1111         }
1112         return deleted_entry(oldtree, current, o);
1116  * Bind merge.
1118  * Keep the index entries at stage0, collapse stage1 but make sure
1119  * stage0 does not have anything there.
1120  */
1121 int bind_merge(struct cache_entry **src,
1122                 struct unpack_trees_options *o)
1124         struct cache_entry *old = src[0];
1125         struct cache_entry *a = src[1];
1127         if (o->merge_size != 1)
1128                 return error("Cannot do a bind merge of %d trees\n",
1129                              o->merge_size);
1130         if (a && old)
1131                 return o->gently ? -1 :
1132                         error(ERRORMSG(o, bind_overlap), a->name, old->name);
1133         if (!a)
1134                 return keep_entry(old, o);
1135         else
1136                 return merged_entry(a, NULL, o);
1140  * One-way merge.
1142  * The rule is:
1143  * - take the stat information from stage0, take the data from stage1
1144  */
1145 int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o)
1147         struct cache_entry *old = src[0];
1148         struct cache_entry *a = src[1];
1150         if (o->merge_size != 1)
1151                 return error("Cannot do a oneway merge of %d trees",
1152                              o->merge_size);
1154         if (!a || a == o->df_conflict_entry)
1155                 return deleted_entry(old, old, o);
1157         if (old && same(old, a)) {
1158                 int update = 0;
1159                 if (o->reset && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1160                         struct stat st;
1161                         if (lstat(old->name, &st) ||
1162                             ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1163                                 update |= CE_UPDATE;
1164                 }
1165                 add_entry(o, old, update, 0);
1166                 return 0;
1167         }
1168         return merged_entry(a, old, o);