Merge 'build-in git-mktree'
[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);
28         free(it);
29         *it_p = NULL;
30 }
31
32 static int subtree_name_cmp(const char *one, int onelen,
33                             const char *two, int twolen)
34 {
35         if (onelen < twolen)
36                 return -1;
37         if (twolen < onelen)
38                 return 1;
39         return memcmp(one, two, onelen);
40 }
41
42 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
43 {
44         struct cache_tree_sub **down = it->down;
45         int lo, hi;
46         lo = 0;
47         hi = it->subtree_nr;
48         while (lo < hi) {
49                 int mi = (lo + hi) / 2;
50                 struct cache_tree_sub *mdl = down[mi];
51                 int cmp = subtree_name_cmp(path, pathlen,
52                                            mdl->name, mdl->namelen);
53                 if (!cmp)
54                         return mi;
55                 if (cmp < 0)
56                         hi = mi;
57                 else
58                         lo = mi + 1;
59         }
60         return -lo-1;
61 }
62
63 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
64                                            const char *path,
65                                            int pathlen,
66                                            int create)
67 {
68         struct cache_tree_sub *down;
69         int pos = subtree_pos(it, path, pathlen);
70         if (0 <= pos)
71                 return it->down[pos];
72         if (!create)
73                 return NULL;
74
75         pos = -pos-1;
76         if (it->subtree_alloc <= it->subtree_nr) {
77                 it->subtree_alloc = alloc_nr(it->subtree_alloc);
78                 it->down = xrealloc(it->down, it->subtree_alloc *
79                                     sizeof(*it->down));
80         }
81         it->subtree_nr++;
82
83         down = xmalloc(sizeof(*down) + pathlen + 1);
84         down->cache_tree = NULL;
85         down->namelen = pathlen;
86         memcpy(down->name, path, pathlen);
87         down->name[pathlen] = 0;
88
89         if (pos < it->subtree_nr)
90                 memmove(it->down + pos + 1,
91                         it->down + pos,
92                         sizeof(down) * (it->subtree_nr - pos - 1));
93         it->down[pos] = down;
94         return down;
95 }
96
97 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
98 {
99         int pathlen = strlen(path);
100         return find_subtree(it, path, pathlen, 1);
101 }
102
103 void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
104 {
105         /* a/b/c
106          * ==> invalidate self
107          * ==> find "a", have it invalidate "b/c"
108          * a
109          * ==> invalidate self
110          * ==> if "a" exists as a subtree, remove it.
111          */
112         const char *slash;
113         int namelen;
114         struct cache_tree_sub *down;
115
116 #if DEBUG
117         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
118 #endif
119
120         if (!it)
121                 return;
122         slash = strchr(path, '/');
123         it->entry_count = -1;
124         if (!slash) {
125                 int pos;
126                 namelen = strlen(path);
127                 pos = subtree_pos(it, path, namelen);
128                 if (0 <= pos) {
129                         cache_tree_free(&it->down[pos]->cache_tree);
130                         free(it->down[pos]);
131                         /* 0 1 2 3 4 5
132                          *       ^     ^subtree_nr = 6
133                          *       pos
134                          * move 4 and 5 up one place (2 entries)
135                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
136                          */
137                         memmove(it->down+pos, it->down+pos+1,
138                                 sizeof(struct cache_tree_sub *) *
139                                 (it->subtree_nr - pos - 1));
140                         it->subtree_nr--;
141                 }
142                 return;
143         }
144         namelen = slash - path;
145         down = find_subtree(it, path, namelen, 0);
146         if (down)
147                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
148 }
149
150 static int verify_cache(struct cache_entry **cache,
151                         int entries)
152 {
153         int i, funny;
154
155         /* Verify that the tree is merged */
156         funny = 0;
157         for (i = 0; i < entries; i++) {
158                 struct cache_entry *ce = cache[i];
159                 if (ce_stage(ce) || (ce->ce_flags & CE_INTENT_TO_ADD)) {
160                         if (10 < ++funny) {
161                                 fprintf(stderr, "...\n");
162                                 break;
163                         }
164                         if (ce_stage(ce))
165                                 fprintf(stderr, "%s: unmerged (%s)\n",
166                                         ce->name, sha1_to_hex(ce->sha1));
167                         else
168                                 fprintf(stderr, "%s: not added yet\n",
169                                         ce->name);
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->sha1))
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 missing_ok,
241                       int dryrun)
242 {
243         struct strbuf buffer;
244         int i;
245
246         if (0 <= it->entry_count && has_sha1_file(it->sha1))
247                 return it->entry_count;
248
249         /*
250          * We first scan for subtrees and update them; we start by
251          * marking existing subtrees -- the ones that are unmarked
252          * should not be in the result.
253          */
254         for (i = 0; i < it->subtree_nr; i++)
255                 it->down[i]->used = 0;
256
257         /*
258          * Find the subtrees and update them.
259          */
260         for (i = 0; i < entries; i++) {
261                 struct cache_entry *ce = cache[i];
262                 struct cache_tree_sub *sub;
263                 const char *path, *slash;
264                 int pathlen, sublen, subcnt;
265
266                 path = ce->name;
267                 pathlen = ce_namelen(ce);
268                 if (pathlen <= baselen || memcmp(base, path, baselen))
269                         break; /* at the end of this level */
270
271                 slash = strchr(path + baselen, '/');
272                 if (!slash)
273                         continue;
274                 /*
275                  * a/bbb/c (base = a/, slash = /c)
276                  * ==>
277                  * path+baselen = bbb/c, sublen = 3
278                  */
279                 sublen = slash - (path + baselen);
280                 sub = find_subtree(it, path + baselen, sublen, 1);
281                 if (!sub->cache_tree)
282                         sub->cache_tree = cache_tree();
283                 subcnt = update_one(sub->cache_tree,
284                                     cache + i, entries - i,
285                                     path,
286                                     baselen + sublen + 1,
287                                     missing_ok,
288                                     dryrun);
289                 if (subcnt < 0)
290                         return subcnt;
291                 i += subcnt - 1;
292                 sub->used = 1;
293         }
294
295         discard_unused_subtrees(it);
296
297         /*
298          * Then write out the tree object for this level.
299          */
300         strbuf_init(&buffer, 8192);
301
302         for (i = 0; i < entries; i++) {
303                 struct cache_entry *ce = cache[i];
304                 struct cache_tree_sub *sub;
305                 const char *path, *slash;
306                 int pathlen, entlen;
307                 const unsigned char *sha1;
308                 unsigned mode;
309
310                 path = ce->name;
311                 pathlen = ce_namelen(ce);
312                 if (pathlen <= baselen || memcmp(base, path, baselen))
313                         break; /* at the end of this level */
314
315                 slash = strchr(path + baselen, '/');
316                 if (slash) {
317                         entlen = slash - (path + baselen);
318                         sub = find_subtree(it, path + baselen, entlen, 0);
319                         if (!sub)
320                                 die("cache-tree.c: '%.*s' in '%s' not found",
321                                     entlen, path + baselen, path);
322                         i += sub->cache_tree->entry_count - 1;
323                         sha1 = sub->cache_tree->sha1;
324                         mode = S_IFDIR;
325                 }
326                 else {
327                         sha1 = ce->sha1;
328                         mode = ce->ce_mode;
329                         entlen = pathlen - baselen;
330                 }
331                 if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1))
332                         return error("invalid object %s", sha1_to_hex(sha1));
333
334                 if (ce->ce_flags & CE_REMOVE)
335                         continue; /* entry being removed */
336
337                 strbuf_grow(&buffer, entlen + 100);
338                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
339                 strbuf_add(&buffer, sha1, 20);
340
341 #if DEBUG
342                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
343                         mode, entlen, path + baselen);
344 #endif
345         }
346
347         if (dryrun)
348                 hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
349         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
350                 strbuf_release(&buffer);
351                 return -1;
352         }
353
354         strbuf_release(&buffer);
355         it->entry_count = i;
356 #if DEBUG
357         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
358                 it->entry_count, it->subtree_nr,
359                 sha1_to_hex(it->sha1));
360 #endif
361         return i;
362 }
363
364 int cache_tree_update(struct cache_tree *it,
365                       struct cache_entry **cache,
366                       int entries,
367                       int missing_ok,
368                       int dryrun)
369 {
370         int i;
371         i = verify_cache(cache, entries);
372         if (i)
373                 return i;
374         i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
375         if (i < 0)
376                 return i;
377         return 0;
378 }
379
380 static void write_one(struct strbuf *buffer, struct cache_tree *it,
381                       const char *path, int pathlen)
382 {
383         int i;
384
385         /* One "cache-tree" entry consists of the following:
386          * path (NUL terminated)
387          * entry_count, subtree_nr ("%d %d\n")
388          * tree-sha1 (missing if invalid)
389          * subtree_nr "cache-tree" entries for subtrees.
390          */
391         strbuf_grow(buffer, pathlen + 100);
392         strbuf_add(buffer, path, pathlen);
393         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
394
395 #if DEBUG
396         if (0 <= it->entry_count)
397                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
398                         pathlen, path, it->entry_count, it->subtree_nr,
399                         sha1_to_hex(it->sha1));
400         else
401                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
402                         pathlen, path, it->subtree_nr);
403 #endif
404
405         if (0 <= it->entry_count) {
406                 strbuf_add(buffer, it->sha1, 20);
407         }
408         for (i = 0; i < it->subtree_nr; i++) {
409                 struct cache_tree_sub *down = it->down[i];
410                 if (i) {
411                         struct cache_tree_sub *prev = it->down[i-1];
412                         if (subtree_name_cmp(down->name, down->namelen,
413                                              prev->name, prev->namelen) <= 0)
414                                 die("fatal - unsorted cache subtree");
415                 }
416                 write_one(buffer, down->cache_tree, down->name, down->namelen);
417         }
418 }
419
420 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
421 {
422         write_one(sb, root, "", 0);
423 }
424
425 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
426 {
427         const char *buf = *buffer;
428         unsigned long size = *size_p;
429         const char *cp;
430         char *ep;
431         struct cache_tree *it;
432         int i, subtree_nr;
433
434         it = NULL;
435         /* skip name, but make sure name exists */
436         while (size && *buf) {
437                 size--;
438                 buf++;
439         }
440         if (!size)
441                 goto free_return;
442         buf++; size--;
443         it = cache_tree();
444
445         cp = buf;
446         it->entry_count = strtol(cp, &ep, 10);
447         if (cp == ep)
448                 goto free_return;
449         cp = ep;
450         subtree_nr = strtol(cp, &ep, 10);
451         if (cp == ep)
452                 goto free_return;
453         while (size && *buf && *buf != '\n') {
454                 size--;
455                 buf++;
456         }
457         if (!size)
458                 goto free_return;
459         buf++; size--;
460         if (0 <= it->entry_count) {
461                 if (size < 20)
462                         goto free_return;
463                 hashcpy(it->sha1, (const unsigned char*)buf);
464                 buf += 20;
465                 size -= 20;
466         }
467
468 #if DEBUG
469         if (0 <= it->entry_count)
470                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
471                         *buffer, it->entry_count, subtree_nr,
472                         sha1_to_hex(it->sha1));
473         else
474                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
475                         *buffer, subtree_nr);
476 #endif
477
478         /*
479          * Just a heuristic -- we do not add directories that often but
480          * we do not want to have to extend it immediately when we do,
481          * hence +2.
482          */
483         it->subtree_alloc = subtree_nr + 2;
484         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
485         for (i = 0; i < subtree_nr; i++) {
486                 /* read each subtree */
487                 struct cache_tree *sub;
488                 struct cache_tree_sub *subtree;
489                 const char *name = buf;
490
491                 sub = read_one(&buf, &size);
492                 if (!sub)
493                         goto free_return;
494                 subtree = cache_tree_sub(it, name);
495                 subtree->cache_tree = sub;
496         }
497         if (subtree_nr != it->subtree_nr)
498                 die("cache-tree: internal error");
499         *buffer = buf;
500         *size_p = size;
501         return it;
502
503  free_return:
504         cache_tree_free(&it);
505         return NULL;
506 }
507
508 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
509 {
510         if (buffer[0])
511                 return NULL; /* not the whole tree */
512         return read_one(&buffer, &size);
513 }
514
515 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
516 {
517         while (*path) {
518                 const char *slash;
519                 struct cache_tree_sub *sub;
520
521                 slash = strchr(path, '/');
522                 if (!slash)
523                         slash = path + strlen(path);
524                 /* between path and slash is the name of the
525                  * subtree to look for.
526                  */
527                 sub = find_subtree(it, path, slash - path, 0);
528                 if (!sub)
529                         return NULL;
530                 it = sub->cache_tree;
531                 if (slash)
532                         while (*slash && *slash == '/')
533                                 slash++;
534                 if (!slash || !*slash)
535                         return it; /* prefix ended with slashes */
536                 path = slash;
537         }
538         return it;
539 }
540
541 int write_cache_as_tree(unsigned char *sha1, int missing_ok, const char *prefix)
542 {
543         int entries, was_valid, newfd;
544
545         /*
546          * We can't free this memory, it becomes part of a linked list
547          * parsed atexit()
548          */
549         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
550
551         newfd = hold_locked_index(lock_file, 1);
552
553         entries = read_cache();
554         if (entries < 0)
555                 return WRITE_TREE_UNREADABLE_INDEX;
556
557         if (!active_cache_tree)
558                 active_cache_tree = cache_tree();
559
560         was_valid = cache_tree_fully_valid(active_cache_tree);
561
562         if (!was_valid) {
563                 if (cache_tree_update(active_cache_tree,
564                                       active_cache, active_nr,
565                                       missing_ok, 0) < 0)
566                         return WRITE_TREE_UNMERGED_INDEX;
567                 if (0 <= newfd) {
568                         if (!write_cache(newfd, active_cache, active_nr) &&
569                             !commit_lock_file(lock_file))
570                                 newfd = -1;
571                 }
572                 /* Not being able to write is fine -- we are only interested
573                  * in updating the cache-tree part, and if the next caller
574                  * ends up using the old index with unupdated cache-tree part
575                  * it misses the work we did here, but that is just a
576                  * performance penalty and not a big deal.
577                  */
578         }
579
580         if (prefix) {
581                 struct cache_tree *subtree =
582                         cache_tree_find(active_cache_tree, prefix);
583                 if (!subtree)
584                         return WRITE_TREE_PREFIX_ERROR;
585                 hashcpy(sha1, subtree->sha1);
586         }
587         else
588                 hashcpy(sha1, active_cache_tree->sha1);
589
590         if (0 <= newfd)
591                 rollback_lock_file(lock_file);
592
593         return 0;
594 }
595
596 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
597 {
598         struct tree_desc desc;
599         struct name_entry entry;
600         int cnt;
601
602         hashcpy(it->sha1, tree->object.sha1);
603         init_tree_desc(&desc, tree->buffer, tree->size);
604         cnt = 0;
605         while (tree_entry(&desc, &entry)) {
606                 if (!S_ISDIR(entry.mode))
607                         cnt++;
608                 else {
609                         struct cache_tree_sub *sub;
610                         struct tree *subtree = lookup_tree(entry.sha1);
611                         if (!subtree->object.parsed)
612                                 parse_tree(subtree);
613                         sub = cache_tree_sub(it, entry.path);
614                         sub->cache_tree = cache_tree();
615                         prime_cache_tree_rec(sub->cache_tree, subtree);
616                         cnt += sub->cache_tree->entry_count;
617                 }
618         }
619         it->entry_count = cnt;
620 }
621
622 void prime_cache_tree(struct cache_tree **it, struct tree *tree)
623 {
624         cache_tree_free(it);
625         *it = cache_tree();
626         prime_cache_tree_rec(*it, tree);
627 }