Merge branch 'pw/sequencer-in-process-commit'
[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 unsigned char *sha1;
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                         sha1 = sub->cache_tree->oid.hash;
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                         sha1 = ce->oid.hash;
351                         mode = ce->ce_mode;
352                         entlen = pathlen - baselen;
353                         i++;
354                 }
355
356                 if (is_null_sha1(sha1) ||
357                     (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1))) {
358                         strbuf_release(&buffer);
359                         if (expected_missing)
360                                 return -1;
361                         return error("invalid object %06o %s for '%.*s'",
362                                 mode, sha1_to_hex(sha1), 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 && !hashcmp(sha1, EMPTY_TREE_SHA1_BIN))
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, sha1, 20);
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                 unsigned char sha1[20];
403                 hash_sha1_file(buffer.buf, buffer.len, tree_type, sha1);
404                 if (has_sha1_file(sha1))
405                         hashcpy(it->oid.hash, sha1);
406                 else
407                         to_invalidate = 1;
408         } else if (dryrun)
409                 hash_sha1_file(buffer.buf, buffer.len, tree_type,
410                                it->oid.hash);
411         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->oid.hash)) {
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, 20);
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
496         it = NULL;
497         /* skip name, but make sure name exists */
498         while (size && *buf) {
499                 size--;
500                 buf++;
501         }
502         if (!size)
503                 goto free_return;
504         buf++; size--;
505         it = cache_tree();
506
507         cp = buf;
508         it->entry_count = strtol(cp, &ep, 10);
509         if (cp == ep)
510                 goto free_return;
511         cp = ep;
512         subtree_nr = strtol(cp, &ep, 10);
513         if (cp == ep)
514                 goto free_return;
515         while (size && *buf && *buf != '\n') {
516                 size--;
517                 buf++;
518         }
519         if (!size)
520                 goto free_return;
521         buf++; size--;
522         if (0 <= it->entry_count) {
523                 if (size < 20)
524                         goto free_return;
525                 hashcpy(it->oid.hash, (const unsigned char*)buf);
526                 buf += 20;
527                 size -= 20;
528         }
529
530 #if DEBUG
531         if (0 <= it->entry_count)
532                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
533                         *buffer, it->entry_count, subtree_nr,
534                         oid_to_hex(&it->oid));
535         else
536                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
537                         *buffer, subtree_nr);
538 #endif
539
540         /*
541          * Just a heuristic -- we do not add directories that often but
542          * we do not want to have to extend it immediately when we do,
543          * hence +2.
544          */
545         it->subtree_alloc = subtree_nr + 2;
546         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
547         for (i = 0; i < subtree_nr; i++) {
548                 /* read each subtree */
549                 struct cache_tree *sub;
550                 struct cache_tree_sub *subtree;
551                 const char *name = buf;
552
553                 sub = read_one(&buf, &size);
554                 if (!sub)
555                         goto free_return;
556                 subtree = cache_tree_sub(it, name);
557                 subtree->cache_tree = sub;
558         }
559         if (subtree_nr != it->subtree_nr)
560                 die("cache-tree: internal error");
561         *buffer = buf;
562         *size_p = size;
563         return it;
564
565  free_return:
566         cache_tree_free(&it);
567         return NULL;
568 }
569
570 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
571 {
572         if (buffer[0])
573                 return NULL; /* not the whole tree */
574         return read_one(&buffer, &size);
575 }
576
577 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
578 {
579         if (!it)
580                 return NULL;
581         while (*path) {
582                 const char *slash;
583                 struct cache_tree_sub *sub;
584
585                 slash = strchrnul(path, '/');
586                 /*
587                  * Between path and slash is the name of the subtree
588                  * to look for.
589                  */
590                 sub = find_subtree(it, path, slash - path, 0);
591                 if (!sub)
592                         return NULL;
593                 it = sub->cache_tree;
594
595                 path = slash;
596                 while (*path == '/')
597                         path++;
598         }
599         return it;
600 }
601
602 int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
603 {
604         int entries, was_valid;
605         struct lock_file lock_file = LOCK_INIT;
606         int ret = 0;
607
608         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
609
610         entries = read_index_from(index_state, index_path, get_git_dir());
611         if (entries < 0) {
612                 ret = WRITE_TREE_UNREADABLE_INDEX;
613                 goto out;
614         }
615         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
616                 cache_tree_free(&index_state->cache_tree);
617
618         if (!index_state->cache_tree)
619                 index_state->cache_tree = cache_tree();
620
621         was_valid = cache_tree_fully_valid(index_state->cache_tree);
622         if (!was_valid) {
623                 if (cache_tree_update(index_state, flags) < 0) {
624                         ret = WRITE_TREE_UNMERGED_INDEX;
625                         goto out;
626                 }
627                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
628                 /* Not being able to write is fine -- we are only interested
629                  * in updating the cache-tree part, and if the next caller
630                  * ends up using the old index with unupdated cache-tree part
631                  * it misses the work we did here, but that is just a
632                  * performance penalty and not a big deal.
633                  */
634         }
635
636         if (prefix) {
637                 struct cache_tree *subtree;
638                 subtree = cache_tree_find(index_state->cache_tree, prefix);
639                 if (!subtree) {
640                         ret = WRITE_TREE_PREFIX_ERROR;
641                         goto out;
642                 }
643                 hashcpy(sha1, subtree->oid.hash);
644         }
645         else
646                 hashcpy(sha1, index_state->cache_tree->oid.hash);
647
648 out:
649         rollback_lock_file(&lock_file);
650         return ret;
651 }
652
653 int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
654 {
655         return write_index_as_tree(sha1, &the_index, get_index_file(), flags, prefix);
656 }
657
658 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
659 {
660         struct tree_desc desc;
661         struct name_entry entry;
662         int cnt;
663
664         oidcpy(&it->oid, &tree->object.oid);
665         init_tree_desc(&desc, tree->buffer, tree->size);
666         cnt = 0;
667         while (tree_entry(&desc, &entry)) {
668                 if (!S_ISDIR(entry.mode))
669                         cnt++;
670                 else {
671                         struct cache_tree_sub *sub;
672                         struct tree *subtree = lookup_tree(entry.oid);
673                         if (!subtree->object.parsed)
674                                 parse_tree(subtree);
675                         sub = cache_tree_sub(it, entry.path);
676                         sub->cache_tree = cache_tree();
677                         prime_cache_tree_rec(sub->cache_tree, subtree);
678                         cnt += sub->cache_tree->entry_count;
679                 }
680         }
681         it->entry_count = cnt;
682 }
683
684 void prime_cache_tree(struct index_state *istate, struct tree *tree)
685 {
686         cache_tree_free(&istate->cache_tree);
687         istate->cache_tree = cache_tree();
688         prime_cache_tree_rec(istate->cache_tree, tree);
689         istate->cache_changed |= CACHE_TREE_CHANGED;
690 }
691
692 /*
693  * find the cache_tree that corresponds to the current level without
694  * exploding the full path into textual form.  The root of the
695  * cache tree is given as "root", and our current level is "info".
696  * (1) When at root level, info->prev is NULL, so it is "root" itself.
697  * (2) Otherwise, find the cache_tree that corresponds to one level
698  *     above us, and find ourselves in there.
699  */
700 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
701                                                          struct traverse_info *info)
702 {
703         struct cache_tree *our_parent;
704
705         if (!info->prev)
706                 return root;
707         our_parent = find_cache_tree_from_traversal(root, info->prev);
708         return cache_tree_find(our_parent, info->name.path);
709 }
710
711 int cache_tree_matches_traversal(struct cache_tree *root,
712                                  struct name_entry *ent,
713                                  struct traverse_info *info)
714 {
715         struct cache_tree *it;
716
717         it = find_cache_tree_from_traversal(root, info);
718         it = cache_tree_find(it, ent->path);
719         if (it && it->entry_count > 0 && !oidcmp(ent->oid, &it->oid))
720                 return it->entry_count;
721         return 0;
722 }
723
724 int update_main_cache_tree(int flags)
725 {
726         if (!the_index.cache_tree)
727                 the_index.cache_tree = cache_tree();
728         return cache_tree_update(&the_index, flags);
729 }