Merge branch 'ws/rebase-p'
[git] / cache-tree.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "tree.h"
4 #include "tree-walk.h"
5 #include "cache-tree.h"
6
7 #ifndef DEBUG
8 #define DEBUG 0
9 #endif
10
11 struct cache_tree *cache_tree(void)
12 {
13         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
14         it->entry_count = -1;
15         return it;
16 }
17
18 void cache_tree_free(struct cache_tree **it_p)
19 {
20         int i;
21         struct cache_tree *it = *it_p;
22
23         if (!it)
24                 return;
25         for (i = 0; i < it->subtree_nr; i++)
26                 if (it->down[i]) {
27                         cache_tree_free(&it->down[i]->cache_tree);
28                         free(it->down[i]);
29                 }
30         free(it->down);
31         free(it);
32         *it_p = NULL;
33 }
34
35 static int subtree_name_cmp(const char *one, int onelen,
36                             const char *two, int twolen)
37 {
38         if (onelen < twolen)
39                 return -1;
40         if (twolen < onelen)
41                 return 1;
42         return memcmp(one, two, onelen);
43 }
44
45 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
46 {
47         struct cache_tree_sub **down = it->down;
48         int lo, hi;
49         lo = 0;
50         hi = it->subtree_nr;
51         while (lo < hi) {
52                 int mi = lo + (hi - lo) / 2;
53                 struct cache_tree_sub *mdl = down[mi];
54                 int cmp = subtree_name_cmp(path, pathlen,
55                                            mdl->name, mdl->namelen);
56                 if (!cmp)
57                         return mi;
58                 if (cmp < 0)
59                         hi = mi;
60                 else
61                         lo = mi + 1;
62         }
63         return -lo-1;
64 }
65
66 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
67                                            const char *path,
68                                            int pathlen,
69                                            int create)
70 {
71         struct cache_tree_sub *down;
72         int pos = subtree_pos(it, path, pathlen);
73         if (0 <= pos)
74                 return it->down[pos];
75         if (!create)
76                 return NULL;
77
78         pos = -pos-1;
79         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
80         it->subtree_nr++;
81
82         FLEX_ALLOC_MEM(down, name, path, pathlen);
83         down->cache_tree = NULL;
84         down->namelen = pathlen;
85
86         if (pos < it->subtree_nr)
87                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
88                            it->subtree_nr - pos - 1);
89         it->down[pos] = down;
90         return down;
91 }
92
93 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
94 {
95         int pathlen = strlen(path);
96         return find_subtree(it, path, pathlen, 1);
97 }
98
99 static int do_invalidate_path(struct cache_tree *it, const char *path)
100 {
101         /* a/b/c
102          * ==> invalidate self
103          * ==> find "a", have it invalidate "b/c"
104          * a
105          * ==> invalidate self
106          * ==> if "a" exists as a subtree, remove it.
107          */
108         const char *slash;
109         int namelen;
110         struct cache_tree_sub *down;
111
112 #if DEBUG
113         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
114 #endif
115
116         if (!it)
117                 return 0;
118         slash = strchrnul(path, '/');
119         namelen = slash - path;
120         it->entry_count = -1;
121         if (!*slash) {
122                 int pos;
123                 pos = subtree_pos(it, path, namelen);
124                 if (0 <= pos) {
125                         cache_tree_free(&it->down[pos]->cache_tree);
126                         free(it->down[pos]);
127                         /* 0 1 2 3 4 5
128                          *       ^     ^subtree_nr = 6
129                          *       pos
130                          * move 4 and 5 up one place (2 entries)
131                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
132                          */
133                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
134                                    it->subtree_nr - pos - 1);
135                         it->subtree_nr--;
136                 }
137                 return 1;
138         }
139         down = find_subtree(it, path, namelen, 0);
140         if (down)
141                 do_invalidate_path(down->cache_tree, slash + 1);
142         return 1;
143 }
144
145 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
146 {
147         if (do_invalidate_path(istate->cache_tree, path))
148                 istate->cache_changed |= CACHE_TREE_CHANGED;
149 }
150
151 static int verify_cache(struct cache_entry **cache,
152                         int entries, int flags)
153 {
154         int i, funny;
155         int silent = flags & WRITE_TREE_SILENT;
156
157         /* Verify that the tree is merged */
158         funny = 0;
159         for (i = 0; i < entries; i++) {
160                 const struct cache_entry *ce = cache[i];
161                 if (ce_stage(ce)) {
162                         if (silent)
163                                 return -1;
164                         if (10 < ++funny) {
165                                 fprintf(stderr, "...\n");
166                                 break;
167                         }
168                         fprintf(stderr, "%s: unmerged (%s)\n",
169                                 ce->name, oid_to_hex(&ce->oid));
170                 }
171         }
172         if (funny)
173                 return -1;
174
175         /* Also verify that the cache does not have path and path/file
176          * at the same time.  At this point we know the cache has only
177          * stage 0 entries.
178          */
179         funny = 0;
180         for (i = 0; i < entries - 1; i++) {
181                 /* path/file always comes after path because of the way
182                  * the cache is sorted.  Also path can appear only once,
183                  * which means conflicting one would immediately follow.
184                  */
185                 const char *this_name = cache[i]->name;
186                 const char *next_name = cache[i+1]->name;
187                 int this_len = strlen(this_name);
188                 if (this_len < strlen(next_name) &&
189                     strncmp(this_name, next_name, this_len) == 0 &&
190                     next_name[this_len] == '/') {
191                         if (10 < ++funny) {
192                                 fprintf(stderr, "...\n");
193                                 break;
194                         }
195                         fprintf(stderr, "You have both %s and %s\n",
196                                 this_name, next_name);
197                 }
198         }
199         if (funny)
200                 return -1;
201         return 0;
202 }
203
204 static void discard_unused_subtrees(struct cache_tree *it)
205 {
206         struct cache_tree_sub **down = it->down;
207         int nr = it->subtree_nr;
208         int dst, src;
209         for (dst = src = 0; src < nr; src++) {
210                 struct cache_tree_sub *s = down[src];
211                 if (s->used)
212                         down[dst++] = s;
213                 else {
214                         cache_tree_free(&s->cache_tree);
215                         free(s);
216                         it->subtree_nr--;
217                 }
218         }
219 }
220
221 int cache_tree_fully_valid(struct cache_tree *it)
222 {
223         int i;
224         if (!it)
225                 return 0;
226         if (it->entry_count < 0 || !has_sha1_file(it->oid.hash))
227                 return 0;
228         for (i = 0; i < it->subtree_nr; i++) {
229                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
230                         return 0;
231         }
232         return 1;
233 }
234
235 static int update_one(struct cache_tree *it,
236                       struct cache_entry **cache,
237                       int entries,
238                       const char *base,
239                       int baselen,
240                       int *skip_count,
241                       int flags)
242 {
243         struct strbuf buffer;
244         int missing_ok = flags & WRITE_TREE_MISSING_OK;
245         int dryrun = flags & WRITE_TREE_DRY_RUN;
246         int repair = flags & WRITE_TREE_REPAIR;
247         int to_invalidate = 0;
248         int i;
249
250         assert(!(dryrun && repair));
251
252         *skip_count = 0;
253
254         if (0 <= it->entry_count && has_sha1_file(it->oid.hash))
255                 return it->entry_count;
256
257         /*
258          * We first scan for subtrees and update them; we start by
259          * marking existing subtrees -- the ones that are unmarked
260          * should not be in the result.
261          */
262         for (i = 0; i < it->subtree_nr; i++)
263                 it->down[i]->used = 0;
264
265         /*
266          * Find the subtrees and update them.
267          */
268         i = 0;
269         while (i < entries) {
270                 const struct cache_entry *ce = cache[i];
271                 struct cache_tree_sub *sub;
272                 const char *path, *slash;
273                 int pathlen, sublen, subcnt, subskip;
274
275                 path = ce->name;
276                 pathlen = ce_namelen(ce);
277                 if (pathlen <= baselen || memcmp(base, path, baselen))
278                         break; /* at the end of this level */
279
280                 slash = strchr(path + baselen, '/');
281                 if (!slash) {
282                         i++;
283                         continue;
284                 }
285                 /*
286                  * a/bbb/c (base = a/, slash = /c)
287                  * ==>
288                  * path+baselen = bbb/c, sublen = 3
289                  */
290                 sublen = slash - (path + baselen);
291                 sub = find_subtree(it, path + baselen, sublen, 1);
292                 if (!sub->cache_tree)
293                         sub->cache_tree = cache_tree();
294                 subcnt = update_one(sub->cache_tree,
295                                     cache + i, entries - i,
296                                     path,
297                                     baselen + sublen + 1,
298                                     &subskip,
299                                     flags);
300                 if (subcnt < 0)
301                         return subcnt;
302                 if (!subcnt)
303                         die("index cache-tree records empty sub-tree");
304                 i += subcnt;
305                 sub->count = subcnt; /* to be used in the next loop */
306                 *skip_count += subskip;
307                 sub->used = 1;
308         }
309
310         discard_unused_subtrees(it);
311
312         /*
313          * Then write out the tree object for this level.
314          */
315         strbuf_init(&buffer, 8192);
316
317         i = 0;
318         while (i < entries) {
319                 const struct cache_entry *ce = cache[i];
320                 struct cache_tree_sub *sub = NULL;
321                 const char *path, *slash;
322                 int pathlen, entlen;
323                 const struct object_id *oid;
324                 unsigned mode;
325                 int expected_missing = 0;
326                 int contains_ita = 0;
327
328                 path = ce->name;
329                 pathlen = ce_namelen(ce);
330                 if (pathlen <= baselen || memcmp(base, path, baselen))
331                         break; /* at the end of this level */
332
333                 slash = strchr(path + baselen, '/');
334                 if (slash) {
335                         entlen = slash - (path + baselen);
336                         sub = find_subtree(it, path + baselen, entlen, 0);
337                         if (!sub)
338                                 die("cache-tree.c: '%.*s' in '%s' not found",
339                                     entlen, path + baselen, path);
340                         i += sub->count;
341                         oid = &sub->cache_tree->oid;
342                         mode = S_IFDIR;
343                         contains_ita = sub->cache_tree->entry_count < 0;
344                         if (contains_ita) {
345                                 to_invalidate = 1;
346                                 expected_missing = 1;
347                         }
348                 }
349                 else {
350                         oid = &ce->oid;
351                         mode = ce->ce_mode;
352                         entlen = pathlen - baselen;
353                         i++;
354                 }
355
356                 if (is_null_oid(oid) ||
357                     (mode != S_IFGITLINK && !missing_ok && !has_object_file(oid))) {
358                         strbuf_release(&buffer);
359                         if (expected_missing)
360                                 return -1;
361                         return error("invalid object %06o %s for '%.*s'",
362                                 mode, oid_to_hex(oid), entlen+baselen, path);
363                 }
364
365                 /*
366                  * CE_REMOVE entries are removed before the index is
367                  * written to disk. Skip them to remain consistent
368                  * with the future on-disk index.
369                  */
370                 if (ce->ce_flags & CE_REMOVE) {
371                         *skip_count = *skip_count + 1;
372                         continue;
373                 }
374
375                 /*
376                  * CE_INTENT_TO_ADD entries exist on on-disk index but
377                  * they are not part of generated trees. Invalidate up
378                  * to root to force cache-tree users to read elsewhere.
379                  */
380                 if (!sub && ce_intent_to_add(ce)) {
381                         to_invalidate = 1;
382                         continue;
383                 }
384
385                 /*
386                  * "sub" can be an empty tree if all subentries are i-t-a.
387                  */
388                 if (contains_ita && !oidcmp(oid, &empty_tree_oid))
389                         continue;
390
391                 strbuf_grow(&buffer, entlen + 100);
392                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
393                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
394
395 #if DEBUG
396                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
397                         mode, entlen, path + baselen);
398 #endif
399         }
400
401         if (repair) {
402                 struct object_id oid;
403                 hash_object_file(buffer.buf, buffer.len, tree_type, &oid);
404                 if (has_object_file(&oid))
405                         oidcpy(&it->oid, &oid);
406                 else
407                         to_invalidate = 1;
408         } else if (dryrun) {
409                 hash_object_file(buffer.buf, buffer.len, tree_type, &it->oid);
410         } else if (write_object_file(buffer.buf, buffer.len, tree_type,
411                                      &it->oid)) {
412                 strbuf_release(&buffer);
413                 return -1;
414         }
415
416         strbuf_release(&buffer);
417         it->entry_count = to_invalidate ? -1 : i - *skip_count;
418 #if DEBUG
419         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
420                 it->entry_count, it->subtree_nr,
421                 oid_to_hex(&it->oid));
422 #endif
423         return i;
424 }
425
426 int cache_tree_update(struct index_state *istate, int flags)
427 {
428         struct cache_tree *it = istate->cache_tree;
429         struct cache_entry **cache = istate->cache;
430         int entries = istate->cache_nr;
431         int skip, i = verify_cache(cache, entries, flags);
432
433         if (i)
434                 return i;
435         i = update_one(it, cache, entries, "", 0, &skip, flags);
436         if (i < 0)
437                 return i;
438         istate->cache_changed |= CACHE_TREE_CHANGED;
439         return 0;
440 }
441
442 static void write_one(struct strbuf *buffer, struct cache_tree *it,
443                       const char *path, int pathlen)
444 {
445         int i;
446
447         /* One "cache-tree" entry consists of the following:
448          * path (NUL terminated)
449          * entry_count, subtree_nr ("%d %d\n")
450          * tree-sha1 (missing if invalid)
451          * subtree_nr "cache-tree" entries for subtrees.
452          */
453         strbuf_grow(buffer, pathlen + 100);
454         strbuf_add(buffer, path, pathlen);
455         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
456
457 #if DEBUG
458         if (0 <= it->entry_count)
459                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
460                         pathlen, path, it->entry_count, it->subtree_nr,
461                         oid_to_hex(&it->oid));
462         else
463                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
464                         pathlen, path, it->subtree_nr);
465 #endif
466
467         if (0 <= it->entry_count) {
468                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
469         }
470         for (i = 0; i < it->subtree_nr; i++) {
471                 struct cache_tree_sub *down = it->down[i];
472                 if (i) {
473                         struct cache_tree_sub *prev = it->down[i-1];
474                         if (subtree_name_cmp(down->name, down->namelen,
475                                              prev->name, prev->namelen) <= 0)
476                                 die("fatal - unsorted cache subtree");
477                 }
478                 write_one(buffer, down->cache_tree, down->name, down->namelen);
479         }
480 }
481
482 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
483 {
484         write_one(sb, root, "", 0);
485 }
486
487 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
488 {
489         const char *buf = *buffer;
490         unsigned long size = *size_p;
491         const char *cp;
492         char *ep;
493         struct cache_tree *it;
494         int i, subtree_nr;
495         const unsigned rawsz = the_hash_algo->rawsz;
496
497         it = NULL;
498         /* skip name, but make sure name exists */
499         while (size && *buf) {
500                 size--;
501                 buf++;
502         }
503         if (!size)
504                 goto free_return;
505         buf++; size--;
506         it = cache_tree();
507
508         cp = buf;
509         it->entry_count = strtol(cp, &ep, 10);
510         if (cp == ep)
511                 goto free_return;
512         cp = ep;
513         subtree_nr = strtol(cp, &ep, 10);
514         if (cp == ep)
515                 goto free_return;
516         while (size && *buf && *buf != '\n') {
517                 size--;
518                 buf++;
519         }
520         if (!size)
521                 goto free_return;
522         buf++; size--;
523         if (0 <= it->entry_count) {
524                 if (size < rawsz)
525                         goto free_return;
526                 memcpy(it->oid.hash, (const unsigned char*)buf, rawsz);
527                 buf += rawsz;
528                 size -= rawsz;
529         }
530
531 #if DEBUG
532         if (0 <= it->entry_count)
533                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
534                         *buffer, it->entry_count, subtree_nr,
535                         oid_to_hex(&it->oid));
536         else
537                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
538                         *buffer, subtree_nr);
539 #endif
540
541         /*
542          * Just a heuristic -- we do not add directories that often but
543          * we do not want to have to extend it immediately when we do,
544          * hence +2.
545          */
546         it->subtree_alloc = subtree_nr + 2;
547         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
548         for (i = 0; i < subtree_nr; i++) {
549                 /* read each subtree */
550                 struct cache_tree *sub;
551                 struct cache_tree_sub *subtree;
552                 const char *name = buf;
553
554                 sub = read_one(&buf, &size);
555                 if (!sub)
556                         goto free_return;
557                 subtree = cache_tree_sub(it, name);
558                 subtree->cache_tree = sub;
559         }
560         if (subtree_nr != it->subtree_nr)
561                 die("cache-tree: internal error");
562         *buffer = buf;
563         *size_p = size;
564         return it;
565
566  free_return:
567         cache_tree_free(&it);
568         return NULL;
569 }
570
571 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
572 {
573         if (buffer[0])
574                 return NULL; /* not the whole tree */
575         return read_one(&buffer, &size);
576 }
577
578 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
579 {
580         if (!it)
581                 return NULL;
582         while (*path) {
583                 const char *slash;
584                 struct cache_tree_sub *sub;
585
586                 slash = strchrnul(path, '/');
587                 /*
588                  * Between path and slash is the name of the subtree
589                  * to look for.
590                  */
591                 sub = find_subtree(it, path, slash - path, 0);
592                 if (!sub)
593                         return NULL;
594                 it = sub->cache_tree;
595
596                 path = slash;
597                 while (*path == '/')
598                         path++;
599         }
600         return it;
601 }
602
603 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
604 {
605         int entries, was_valid;
606         struct lock_file lock_file = LOCK_INIT;
607         int ret = 0;
608
609         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
610
611         entries = read_index_from(index_state, index_path, get_git_dir());
612         if (entries < 0) {
613                 ret = WRITE_TREE_UNREADABLE_INDEX;
614                 goto out;
615         }
616         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
617                 cache_tree_free(&index_state->cache_tree);
618
619         if (!index_state->cache_tree)
620                 index_state->cache_tree = cache_tree();
621
622         was_valid = cache_tree_fully_valid(index_state->cache_tree);
623         if (!was_valid) {
624                 if (cache_tree_update(index_state, flags) < 0) {
625                         ret = WRITE_TREE_UNMERGED_INDEX;
626                         goto out;
627                 }
628                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
629                 /* Not being able to write is fine -- we are only interested
630                  * in updating the cache-tree part, and if the next caller
631                  * ends up using the old index with unupdated cache-tree part
632                  * it misses the work we did here, but that is just a
633                  * performance penalty and not a big deal.
634                  */
635         }
636
637         if (prefix) {
638                 struct cache_tree *subtree;
639                 subtree = cache_tree_find(index_state->cache_tree, prefix);
640                 if (!subtree) {
641                         ret = WRITE_TREE_PREFIX_ERROR;
642                         goto out;
643                 }
644                 oidcpy(oid, &subtree->oid);
645         }
646         else
647                 oidcpy(oid, &index_state->cache_tree->oid);
648
649 out:
650         rollback_lock_file(&lock_file);
651         return ret;
652 }
653
654 int write_cache_as_tree(struct object_id *oid, int flags, const char *prefix)
655 {
656         return write_index_as_tree(oid, &the_index, get_index_file(), flags, prefix);
657 }
658
659 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
660 {
661         struct tree_desc desc;
662         struct name_entry entry;
663         int cnt;
664
665         oidcpy(&it->oid, &tree->object.oid);
666         init_tree_desc(&desc, tree->buffer, tree->size);
667         cnt = 0;
668         while (tree_entry(&desc, &entry)) {
669                 if (!S_ISDIR(entry.mode))
670                         cnt++;
671                 else {
672                         struct cache_tree_sub *sub;
673                         struct tree *subtree = lookup_tree(entry.oid);
674                         if (!subtree->object.parsed)
675                                 parse_tree(subtree);
676                         sub = cache_tree_sub(it, entry.path);
677                         sub->cache_tree = cache_tree();
678                         prime_cache_tree_rec(sub->cache_tree, subtree);
679                         cnt += sub->cache_tree->entry_count;
680                 }
681         }
682         it->entry_count = cnt;
683 }
684
685 void prime_cache_tree(struct index_state *istate, struct tree *tree)
686 {
687         cache_tree_free(&istate->cache_tree);
688         istate->cache_tree = cache_tree();
689         prime_cache_tree_rec(istate->cache_tree, tree);
690         istate->cache_changed |= CACHE_TREE_CHANGED;
691 }
692
693 /*
694  * find the cache_tree that corresponds to the current level without
695  * exploding the full path into textual form.  The root of the
696  * cache tree is given as "root", and our current level is "info".
697  * (1) When at root level, info->prev is NULL, so it is "root" itself.
698  * (2) Otherwise, find the cache_tree that corresponds to one level
699  *     above us, and find ourselves in there.
700  */
701 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
702                                                          struct traverse_info *info)
703 {
704         struct cache_tree *our_parent;
705
706         if (!info->prev)
707                 return root;
708         our_parent = find_cache_tree_from_traversal(root, info->prev);
709         return cache_tree_find(our_parent, info->name.path);
710 }
711
712 int cache_tree_matches_traversal(struct cache_tree *root,
713                                  struct name_entry *ent,
714                                  struct traverse_info *info)
715 {
716         struct cache_tree *it;
717
718         it = find_cache_tree_from_traversal(root, info);
719         it = cache_tree_find(it, ent->path);
720         if (it && it->entry_count > 0 && !oidcmp(ent->oid, &it->oid))
721                 return it->entry_count;
722         return 0;
723 }
724
725 int update_main_cache_tree(int flags)
726 {
727         if (!the_index.cache_tree)
728                 the_index.cache_tree = cache_tree();
729         return cache_tree_update(&the_index, flags);
730 }