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