Merge branch 'cn/maint-branch-with-bad'
[git] / cache-tree.c
1 #include "cache.h"
2 #include "tree.h"
3 #include "tree-walk.h"
4 #include "cache-tree.h"
5
6 #ifndef DEBUG
7 #define DEBUG 0
8 #endif
9
10 struct cache_tree *cache_tree(void)
11 {
12         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
13         it->entry_count = -1;
14         return it;
15 }
16
17 void cache_tree_free(struct cache_tree **it_p)
18 {
19         int i;
20         struct cache_tree *it = *it_p;
21
22         if (!it)
23                 return;
24         for (i = 0; i < it->subtree_nr; i++)
25                 if (it->down[i]) {
26                         cache_tree_free(&it->down[i]->cache_tree);
27                         free(it->down[i]);
28                 }
29         free(it->down);
30         free(it);
31         *it_p = NULL;
32 }
33
34 static int subtree_name_cmp(const char *one, int onelen,
35                             const char *two, int twolen)
36 {
37         if (onelen < twolen)
38                 return -1;
39         if (twolen < onelen)
40                 return 1;
41         return memcmp(one, two, onelen);
42 }
43
44 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
45 {
46         struct cache_tree_sub **down = it->down;
47         int lo, hi;
48         lo = 0;
49         hi = it->subtree_nr;
50         while (lo < hi) {
51                 int mi = (lo + hi) / 2;
52                 struct cache_tree_sub *mdl = down[mi];
53                 int cmp = subtree_name_cmp(path, pathlen,
54                                            mdl->name, mdl->namelen);
55                 if (!cmp)
56                         return mi;
57                 if (cmp < 0)
58                         hi = mi;
59                 else
60                         lo = mi + 1;
61         }
62         return -lo-1;
63 }
64
65 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
66                                            const char *path,
67                                            int pathlen,
68                                            int create)
69 {
70         struct cache_tree_sub *down;
71         int pos = subtree_pos(it, path, pathlen);
72         if (0 <= pos)
73                 return it->down[pos];
74         if (!create)
75                 return NULL;
76
77         pos = -pos-1;
78         if (it->subtree_alloc <= it->subtree_nr) {
79                 it->subtree_alloc = alloc_nr(it->subtree_alloc);
80                 it->down = xrealloc(it->down, it->subtree_alloc *
81                                     sizeof(*it->down));
82         }
83         it->subtree_nr++;
84
85         down = xmalloc(sizeof(*down) + pathlen + 1);
86         down->cache_tree = NULL;
87         down->namelen = pathlen;
88         memcpy(down->name, path, pathlen);
89         down->name[pathlen] = 0;
90
91         if (pos < it->subtree_nr)
92                 memmove(it->down + pos + 1,
93                         it->down + pos,
94                         sizeof(down) * (it->subtree_nr - pos - 1));
95         it->down[pos] = down;
96         return down;
97 }
98
99 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
100 {
101         int pathlen = strlen(path);
102         return find_subtree(it, path, pathlen, 1);
103 }
104
105 void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
106 {
107         /* a/b/c
108          * ==> invalidate self
109          * ==> find "a", have it invalidate "b/c"
110          * a
111          * ==> invalidate self
112          * ==> if "a" exists as a subtree, remove it.
113          */
114         const char *slash;
115         int namelen;
116         struct cache_tree_sub *down;
117
118 #if DEBUG
119         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
120 #endif
121
122         if (!it)
123                 return;
124         slash = strchr(path, '/');
125         it->entry_count = -1;
126         if (!slash) {
127                 int pos;
128                 namelen = strlen(path);
129                 pos = subtree_pos(it, path, namelen);
130                 if (0 <= pos) {
131                         cache_tree_free(&it->down[pos]->cache_tree);
132                         free(it->down[pos]);
133                         /* 0 1 2 3 4 5
134                          *       ^     ^subtree_nr = 6
135                          *       pos
136                          * move 4 and 5 up one place (2 entries)
137                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
138                          */
139                         memmove(it->down+pos, it->down+pos+1,
140                                 sizeof(struct cache_tree_sub *) *
141                                 (it->subtree_nr - pos - 1));
142                         it->subtree_nr--;
143                 }
144                 return;
145         }
146         namelen = slash - path;
147         down = find_subtree(it, path, namelen, 0);
148         if (down)
149                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
150 }
151
152 static int verify_cache(struct cache_entry **cache,
153                         int entries, int flags)
154 {
155         int i, funny;
156         int silent = flags & WRITE_TREE_SILENT;
157
158         /* Verify that the tree is merged */
159         funny = 0;
160         for (i = 0; i < entries; i++) {
161                 struct cache_entry *ce = cache[i];
162                 if (ce_stage(ce)) {
163                         if (silent)
164                                 return -1;
165                         if (10 < ++funny) {
166                                 fprintf(stderr, "...\n");
167                                 break;
168                         }
169                         if (ce_stage(ce))
170                                 fprintf(stderr, "%s: unmerged (%s)\n",
171                                         ce->name, sha1_to_hex(ce->sha1));
172                         else
173                                 fprintf(stderr, "%s: not added yet\n",
174                                         ce->name);
175                 }
176         }
177         if (funny)
178                 return -1;
179
180         /* Also verify that the cache does not have path and path/file
181          * at the same time.  At this point we know the cache has only
182          * stage 0 entries.
183          */
184         funny = 0;
185         for (i = 0; i < entries - 1; i++) {
186                 /* path/file always comes after path because of the way
187                  * the cache is sorted.  Also path can appear only once,
188                  * which means conflicting one would immediately follow.
189                  */
190                 const char *this_name = cache[i]->name;
191                 const char *next_name = cache[i+1]->name;
192                 int this_len = strlen(this_name);
193                 if (this_len < strlen(next_name) &&
194                     strncmp(this_name, next_name, this_len) == 0 &&
195                     next_name[this_len] == '/') {
196                         if (10 < ++funny) {
197                                 fprintf(stderr, "...\n");
198                                 break;
199                         }
200                         fprintf(stderr, "You have both %s and %s\n",
201                                 this_name, next_name);
202                 }
203         }
204         if (funny)
205                 return -1;
206         return 0;
207 }
208
209 static void discard_unused_subtrees(struct cache_tree *it)
210 {
211         struct cache_tree_sub **down = it->down;
212         int nr = it->subtree_nr;
213         int dst, src;
214         for (dst = src = 0; src < nr; src++) {
215                 struct cache_tree_sub *s = down[src];
216                 if (s->used)
217                         down[dst++] = s;
218                 else {
219                         cache_tree_free(&s->cache_tree);
220                         free(s);
221                         it->subtree_nr--;
222                 }
223         }
224 }
225
226 int cache_tree_fully_valid(struct cache_tree *it)
227 {
228         int i;
229         if (!it)
230                 return 0;
231         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
232                 return 0;
233         for (i = 0; i < it->subtree_nr; i++) {
234                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
235                         return 0;
236         }
237         return 1;
238 }
239
240 static int update_one(struct cache_tree *it,
241                       struct cache_entry **cache,
242                       int entries,
243                       const char *base,
244                       int baselen,
245                       int flags)
246 {
247         struct strbuf buffer;
248         int missing_ok = flags & WRITE_TREE_MISSING_OK;
249         int dryrun = flags & WRITE_TREE_DRY_RUN;
250         int i;
251
252         if (0 <= it->entry_count && has_sha1_file(it->sha1))
253                 return it->entry_count;
254
255         /*
256          * We first scan for subtrees and update them; we start by
257          * marking existing subtrees -- the ones that are unmarked
258          * should not be in the result.
259          */
260         for (i = 0; i < it->subtree_nr; i++)
261                 it->down[i]->used = 0;
262
263         /*
264          * Find the subtrees and update them.
265          */
266         for (i = 0; i < entries; i++) {
267                 struct cache_entry *ce = cache[i];
268                 struct cache_tree_sub *sub;
269                 const char *path, *slash;
270                 int pathlen, sublen, subcnt;
271
272                 path = ce->name;
273                 pathlen = ce_namelen(ce);
274                 if (pathlen <= baselen || memcmp(base, path, baselen))
275                         break; /* at the end of this level */
276
277                 slash = strchr(path + baselen, '/');
278                 if (!slash)
279                         continue;
280                 /*
281                  * a/bbb/c (base = a/, slash = /c)
282                  * ==>
283                  * path+baselen = bbb/c, sublen = 3
284                  */
285                 sublen = slash - (path + baselen);
286                 sub = find_subtree(it, path + baselen, sublen, 1);
287                 if (!sub->cache_tree)
288                         sub->cache_tree = cache_tree();
289                 subcnt = update_one(sub->cache_tree,
290                                     cache + i, entries - i,
291                                     path,
292                                     baselen + sublen + 1,
293                                     flags);
294                 if (subcnt < 0)
295                         return subcnt;
296                 i += subcnt - 1;
297                 sub->used = 1;
298         }
299
300         discard_unused_subtrees(it);
301
302         /*
303          * Then write out the tree object for this level.
304          */
305         strbuf_init(&buffer, 8192);
306
307         for (i = 0; i < entries; i++) {
308                 struct cache_entry *ce = cache[i];
309                 struct cache_tree_sub *sub;
310                 const char *path, *slash;
311                 int pathlen, entlen;
312                 const unsigned char *sha1;
313                 unsigned mode;
314
315                 path = ce->name;
316                 pathlen = ce_namelen(ce);
317                 if (pathlen <= baselen || memcmp(base, path, baselen))
318                         break; /* at the end of this level */
319
320                 slash = strchr(path + baselen, '/');
321                 if (slash) {
322                         entlen = slash - (path + baselen);
323                         sub = find_subtree(it, path + baselen, entlen, 0);
324                         if (!sub)
325                                 die("cache-tree.c: '%.*s' in '%s' not found",
326                                     entlen, path + baselen, path);
327                         i += sub->cache_tree->entry_count - 1;
328                         sha1 = sub->cache_tree->sha1;
329                         mode = S_IFDIR;
330                 }
331                 else {
332                         sha1 = ce->sha1;
333                         mode = ce->ce_mode;
334                         entlen = pathlen - baselen;
335                 }
336                 if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1)) {
337                         strbuf_release(&buffer);
338                         return error("invalid object %06o %s for '%.*s'",
339                                 mode, sha1_to_hex(sha1), entlen+baselen, path);
340                 }
341
342                 if (ce->ce_flags & (CE_REMOVE | CE_INTENT_TO_ADD))
343                         continue; /* entry being removed or placeholder */
344
345                 strbuf_grow(&buffer, entlen + 100);
346                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
347                 strbuf_add(&buffer, sha1, 20);
348
349 #if DEBUG
350                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
351                         mode, entlen, path + baselen);
352 #endif
353         }
354
355         if (dryrun)
356                 hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
357         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
358                 strbuf_release(&buffer);
359                 return -1;
360         }
361
362         strbuf_release(&buffer);
363         it->entry_count = i;
364 #if DEBUG
365         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
366                 it->entry_count, it->subtree_nr,
367                 sha1_to_hex(it->sha1));
368 #endif
369         return i;
370 }
371
372 int cache_tree_update(struct cache_tree *it,
373                       struct cache_entry **cache,
374                       int entries,
375                       int flags)
376 {
377         int i;
378         i = verify_cache(cache, entries, flags);
379         if (i)
380                 return i;
381         i = update_one(it, cache, entries, "", 0, flags);
382         if (i < 0)
383                 return i;
384         return 0;
385 }
386
387 static void write_one(struct strbuf *buffer, struct cache_tree *it,
388                       const char *path, int pathlen)
389 {
390         int i;
391
392         /* One "cache-tree" entry consists of the following:
393          * path (NUL terminated)
394          * entry_count, subtree_nr ("%d %d\n")
395          * tree-sha1 (missing if invalid)
396          * subtree_nr "cache-tree" entries for subtrees.
397          */
398         strbuf_grow(buffer, pathlen + 100);
399         strbuf_add(buffer, path, pathlen);
400         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
401
402 #if DEBUG
403         if (0 <= it->entry_count)
404                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
405                         pathlen, path, it->entry_count, it->subtree_nr,
406                         sha1_to_hex(it->sha1));
407         else
408                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
409                         pathlen, path, it->subtree_nr);
410 #endif
411
412         if (0 <= it->entry_count) {
413                 strbuf_add(buffer, it->sha1, 20);
414         }
415         for (i = 0; i < it->subtree_nr; i++) {
416                 struct cache_tree_sub *down = it->down[i];
417                 if (i) {
418                         struct cache_tree_sub *prev = it->down[i-1];
419                         if (subtree_name_cmp(down->name, down->namelen,
420                                              prev->name, prev->namelen) <= 0)
421                                 die("fatal - unsorted cache subtree");
422                 }
423                 write_one(buffer, down->cache_tree, down->name, down->namelen);
424         }
425 }
426
427 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
428 {
429         write_one(sb, root, "", 0);
430 }
431
432 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
433 {
434         const char *buf = *buffer;
435         unsigned long size = *size_p;
436         const char *cp;
437         char *ep;
438         struct cache_tree *it;
439         int i, subtree_nr;
440
441         it = NULL;
442         /* skip name, but make sure name exists */
443         while (size && *buf) {
444                 size--;
445                 buf++;
446         }
447         if (!size)
448                 goto free_return;
449         buf++; size--;
450         it = cache_tree();
451
452         cp = buf;
453         it->entry_count = strtol(cp, &ep, 10);
454         if (cp == ep)
455                 goto free_return;
456         cp = ep;
457         subtree_nr = strtol(cp, &ep, 10);
458         if (cp == ep)
459                 goto free_return;
460         while (size && *buf && *buf != '\n') {
461                 size--;
462                 buf++;
463         }
464         if (!size)
465                 goto free_return;
466         buf++; size--;
467         if (0 <= it->entry_count) {
468                 if (size < 20)
469                         goto free_return;
470                 hashcpy(it->sha1, (const unsigned char*)buf);
471                 buf += 20;
472                 size -= 20;
473         }
474
475 #if DEBUG
476         if (0 <= it->entry_count)
477                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
478                         *buffer, it->entry_count, subtree_nr,
479                         sha1_to_hex(it->sha1));
480         else
481                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
482                         *buffer, subtree_nr);
483 #endif
484
485         /*
486          * Just a heuristic -- we do not add directories that often but
487          * we do not want to have to extend it immediately when we do,
488          * hence +2.
489          */
490         it->subtree_alloc = subtree_nr + 2;
491         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
492         for (i = 0; i < subtree_nr; i++) {
493                 /* read each subtree */
494                 struct cache_tree *sub;
495                 struct cache_tree_sub *subtree;
496                 const char *name = buf;
497
498                 sub = read_one(&buf, &size);
499                 if (!sub)
500                         goto free_return;
501                 subtree = cache_tree_sub(it, name);
502                 subtree->cache_tree = sub;
503         }
504         if (subtree_nr != it->subtree_nr)
505                 die("cache-tree: internal error");
506         *buffer = buf;
507         *size_p = size;
508         return it;
509
510  free_return:
511         cache_tree_free(&it);
512         return NULL;
513 }
514
515 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
516 {
517         if (buffer[0])
518                 return NULL; /* not the whole tree */
519         return read_one(&buffer, &size);
520 }
521
522 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
523 {
524         if (!it)
525                 return NULL;
526         while (*path) {
527                 const char *slash;
528                 struct cache_tree_sub *sub;
529
530                 slash = strchr(path, '/');
531                 if (!slash)
532                         slash = path + strlen(path);
533                 /* between path and slash is the name of the
534                  * subtree to look for.
535                  */
536                 sub = find_subtree(it, path, slash - path, 0);
537                 if (!sub)
538                         return NULL;
539                 it = sub->cache_tree;
540                 if (slash)
541                         while (*slash && *slash == '/')
542                                 slash++;
543                 if (!slash || !*slash)
544                         return it; /* prefix ended with slashes */
545                 path = slash;
546         }
547         return it;
548 }
549
550 int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
551 {
552         int entries, was_valid, newfd;
553         struct lock_file *lock_file;
554
555         /*
556          * We can't free this memory, it becomes part of a linked list
557          * parsed atexit()
558          */
559         lock_file = xcalloc(1, sizeof(struct lock_file));
560
561         newfd = hold_locked_index(lock_file, 1);
562
563         entries = read_cache();
564         if (entries < 0)
565                 return WRITE_TREE_UNREADABLE_INDEX;
566         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
567                 cache_tree_free(&(active_cache_tree));
568
569         if (!active_cache_tree)
570                 active_cache_tree = cache_tree();
571
572         was_valid = cache_tree_fully_valid(active_cache_tree);
573         if (!was_valid) {
574                 if (cache_tree_update(active_cache_tree,
575                                       active_cache, active_nr,
576                                       flags) < 0)
577                         return WRITE_TREE_UNMERGED_INDEX;
578                 if (0 <= newfd) {
579                         if (!write_cache(newfd, active_cache, active_nr) &&
580                             !commit_lock_file(lock_file))
581                                 newfd = -1;
582                 }
583                 /* Not being able to write is fine -- we are only interested
584                  * in updating the cache-tree part, and if the next caller
585                  * ends up using the old index with unupdated cache-tree part
586                  * it misses the work we did here, but that is just a
587                  * performance penalty and not a big deal.
588                  */
589         }
590
591         if (prefix) {
592                 struct cache_tree *subtree =
593                         cache_tree_find(active_cache_tree, prefix);
594                 if (!subtree)
595                         return WRITE_TREE_PREFIX_ERROR;
596                 hashcpy(sha1, subtree->sha1);
597         }
598         else
599                 hashcpy(sha1, active_cache_tree->sha1);
600
601         if (0 <= newfd)
602                 rollback_lock_file(lock_file);
603
604         return 0;
605 }
606
607 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
608 {
609         struct tree_desc desc;
610         struct name_entry entry;
611         int cnt;
612
613         hashcpy(it->sha1, tree->object.sha1);
614         init_tree_desc(&desc, tree->buffer, tree->size);
615         cnt = 0;
616         while (tree_entry(&desc, &entry)) {
617                 if (!S_ISDIR(entry.mode))
618                         cnt++;
619                 else {
620                         struct cache_tree_sub *sub;
621                         struct tree *subtree = lookup_tree(entry.sha1);
622                         if (!subtree->object.parsed)
623                                 parse_tree(subtree);
624                         sub = cache_tree_sub(it, entry.path);
625                         sub->cache_tree = cache_tree();
626                         prime_cache_tree_rec(sub->cache_tree, subtree);
627                         cnt += sub->cache_tree->entry_count;
628                 }
629         }
630         it->entry_count = cnt;
631 }
632
633 void prime_cache_tree(struct cache_tree **it, struct tree *tree)
634 {
635         cache_tree_free(it);
636         *it = cache_tree();
637         prime_cache_tree_rec(*it, tree);
638 }
639
640 /*
641  * find the cache_tree that corresponds to the current level without
642  * exploding the full path into textual form.  The root of the
643  * cache tree is given as "root", and our current level is "info".
644  * (1) When at root level, info->prev is NULL, so it is "root" itself.
645  * (2) Otherwise, find the cache_tree that corresponds to one level
646  *     above us, and find ourselves in there.
647  */
648 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
649                                                          struct traverse_info *info)
650 {
651         struct cache_tree *our_parent;
652
653         if (!info->prev)
654                 return root;
655         our_parent = find_cache_tree_from_traversal(root, info->prev);
656         return cache_tree_find(our_parent, info->name.path);
657 }
658
659 int cache_tree_matches_traversal(struct cache_tree *root,
660                                  struct name_entry *ent,
661                                  struct traverse_info *info)
662 {
663         struct cache_tree *it;
664
665         it = find_cache_tree_from_traversal(root, info);
666         it = cache_tree_find(it, ent->path);
667         if (it && it->entry_count > 0 && !hashcmp(ent->sha1, it->sha1))
668                 return it->entry_count;
669         return 0;
670 }
671
672 int update_main_cache_tree(int flags)
673 {
674         if (!the_index.cache_tree)
675                 the_index.cache_tree = cache_tree();
676         return cache_tree_update(the_index.cache_tree,
677                                  the_index.cache, the_index.cache_nr, flags);
678 }