do_for_each_entry_in_dir(): eliminate `offset` argument
[git/git.git] / refs / ref-cache.c
1 #include "../cache.h"
2 #include "../refs.h"
3 #include "refs-internal.h"
4 #include "ref-cache.h"
5 #include "../iterator.h"
6
7 void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
8 {
9 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
10 dir->entries[dir->nr++] = entry;
11 /* optimize for the case that entries are added in order */
12 if (dir->nr == 1 ||
13 (dir->nr == dir->sorted + 1 &&
14 strcmp(dir->entries[dir->nr - 2]->name,
15 dir->entries[dir->nr - 1]->name) < 0))
16 dir->sorted = dir->nr;
17 }
18
19 struct ref_dir *get_ref_dir(struct ref_entry *entry)
20 {
21 struct ref_dir *dir;
22 assert(entry->flag & REF_DIR);
23 dir = &entry->u.subdir;
24 if (entry->flag & REF_INCOMPLETE) {
25 if (!dir->cache->fill_ref_dir)
26 die("BUG: incomplete ref_store without fill_ref_dir function");
27
28 dir->cache->fill_ref_dir(dir->cache->ref_store, dir, entry->name);
29 entry->flag &= ~REF_INCOMPLETE;
30 }
31 return dir;
32 }
33
34 struct ref_entry *create_ref_entry(const char *refname,
35 const unsigned char *sha1, int flag,
36 int check_name)
37 {
38 struct ref_entry *ref;
39
40 if (check_name &&
41 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
42 die("Reference has invalid format: '%s'", refname);
43 FLEX_ALLOC_STR(ref, name, refname);
44 hashcpy(ref->u.value.oid.hash, sha1);
45 oidclr(&ref->u.value.peeled);
46 ref->flag = flag;
47 return ref;
48 }
49
50 struct ref_cache *create_ref_cache(struct ref_store *refs,
51 fill_ref_dir_fn *fill_ref_dir)
52 {
53 struct ref_cache *ret = xcalloc(1, sizeof(*ret));
54
55 ret->ref_store = refs;
56 ret->fill_ref_dir = fill_ref_dir;
57 ret->root = create_dir_entry(ret, "", 0, 1);
58 return ret;
59 }
60
61 static void clear_ref_dir(struct ref_dir *dir);
62
63 static void free_ref_entry(struct ref_entry *entry)
64 {
65 if (entry->flag & REF_DIR) {
66 /*
67 * Do not use get_ref_dir() here, as that might
68 * trigger the reading of loose refs.
69 */
70 clear_ref_dir(&entry->u.subdir);
71 }
72 free(entry);
73 }
74
75 void free_ref_cache(struct ref_cache *cache)
76 {
77 free_ref_entry(cache->root);
78 free(cache);
79 }
80
81 /*
82 * Clear and free all entries in dir, recursively.
83 */
84 static void clear_ref_dir(struct ref_dir *dir)
85 {
86 int i;
87 for (i = 0; i < dir->nr; i++)
88 free_ref_entry(dir->entries[i]);
89 free(dir->entries);
90 dir->sorted = dir->nr = dir->alloc = 0;
91 dir->entries = NULL;
92 }
93
94 struct ref_entry *create_dir_entry(struct ref_cache *cache,
95 const char *dirname, size_t len,
96 int incomplete)
97 {
98 struct ref_entry *direntry;
99
100 FLEX_ALLOC_MEM(direntry, name, dirname, len);
101 direntry->u.subdir.cache = cache;
102 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
103 return direntry;
104 }
105
106 static int ref_entry_cmp(const void *a, const void *b)
107 {
108 struct ref_entry *one = *(struct ref_entry **)a;
109 struct ref_entry *two = *(struct ref_entry **)b;
110 return strcmp(one->name, two->name);
111 }
112
113 static void sort_ref_dir(struct ref_dir *dir);
114
115 struct string_slice {
116 size_t len;
117 const char *str;
118 };
119
120 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
121 {
122 const struct string_slice *key = key_;
123 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
124 int cmp = strncmp(key->str, ent->name, key->len);
125 if (cmp)
126 return cmp;
127 return '\0' - (unsigned char)ent->name[key->len];
128 }
129
130 int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
131 {
132 struct ref_entry **r;
133 struct string_slice key;
134
135 if (refname == NULL || !dir->nr)
136 return -1;
137
138 sort_ref_dir(dir);
139 key.len = len;
140 key.str = refname;
141 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
142 ref_entry_cmp_sslice);
143
144 if (r == NULL)
145 return -1;
146
147 return r - dir->entries;
148 }
149
150 /*
151 * Search for a directory entry directly within dir (without
152 * recursing). Sort dir if necessary. subdirname must be a directory
153 * name (i.e., end in '/'). If mkdir is set, then create the
154 * directory if it is missing; otherwise, return NULL if the desired
155 * directory cannot be found. dir must already be complete.
156 */
157 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
158 const char *subdirname, size_t len,
159 int mkdir)
160 {
161 int entry_index = search_ref_dir(dir, subdirname, len);
162 struct ref_entry *entry;
163 if (entry_index == -1) {
164 if (!mkdir)
165 return NULL;
166 /*
167 * Since dir is complete, the absence of a subdir
168 * means that the subdir really doesn't exist;
169 * therefore, create an empty record for it but mark
170 * the record complete.
171 */
172 entry = create_dir_entry(dir->cache, subdirname, len, 0);
173 add_entry_to_dir(dir, entry);
174 } else {
175 entry = dir->entries[entry_index];
176 }
177 return get_ref_dir(entry);
178 }
179
180 struct ref_dir *find_containing_dir(struct ref_dir *dir,
181 const char *refname, int mkdir)
182 {
183 const char *slash;
184 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
185 size_t dirnamelen = slash - refname + 1;
186 struct ref_dir *subdir;
187 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
188 if (!subdir) {
189 dir = NULL;
190 break;
191 }
192 dir = subdir;
193 }
194
195 return dir;
196 }
197
198 struct ref_entry *find_ref_entry(struct ref_dir *dir, const char *refname)
199 {
200 int entry_index;
201 struct ref_entry *entry;
202 dir = find_containing_dir(dir, refname, 0);
203 if (!dir)
204 return NULL;
205 entry_index = search_ref_dir(dir, refname, strlen(refname));
206 if (entry_index == -1)
207 return NULL;
208 entry = dir->entries[entry_index];
209 return (entry->flag & REF_DIR) ? NULL : entry;
210 }
211
212 int remove_entry_from_dir(struct ref_dir *dir, const char *refname)
213 {
214 int refname_len = strlen(refname);
215 int entry_index;
216 struct ref_entry *entry;
217 int is_dir = refname[refname_len - 1] == '/';
218 if (is_dir) {
219 /*
220 * refname represents a reference directory. Remove
221 * the trailing slash; otherwise we will get the
222 * directory *representing* refname rather than the
223 * one *containing* it.
224 */
225 char *dirname = xmemdupz(refname, refname_len - 1);
226 dir = find_containing_dir(dir, dirname, 0);
227 free(dirname);
228 } else {
229 dir = find_containing_dir(dir, refname, 0);
230 }
231 if (!dir)
232 return -1;
233 entry_index = search_ref_dir(dir, refname, refname_len);
234 if (entry_index == -1)
235 return -1;
236 entry = dir->entries[entry_index];
237
238 memmove(&dir->entries[entry_index],
239 &dir->entries[entry_index + 1],
240 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
241 );
242 dir->nr--;
243 if (dir->sorted > entry_index)
244 dir->sorted--;
245 free_ref_entry(entry);
246 return dir->nr;
247 }
248
249 int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref)
250 {
251 dir = find_containing_dir(dir, ref->name, 1);
252 if (!dir)
253 return -1;
254 add_entry_to_dir(dir, ref);
255 return 0;
256 }
257
258 /*
259 * Emit a warning and return true iff ref1 and ref2 have the same name
260 * and the same sha1. Die if they have the same name but different
261 * sha1s.
262 */
263 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
264 {
265 if (strcmp(ref1->name, ref2->name))
266 return 0;
267
268 /* Duplicate name; make sure that they don't conflict: */
269
270 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
271 /* This is impossible by construction */
272 die("Reference directory conflict: %s", ref1->name);
273
274 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
275 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
276
277 warning("Duplicated ref: %s", ref1->name);
278 return 1;
279 }
280
281 /*
282 * Sort the entries in dir non-recursively (if they are not already
283 * sorted) and remove any duplicate entries.
284 */
285 static void sort_ref_dir(struct ref_dir *dir)
286 {
287 int i, j;
288 struct ref_entry *last = NULL;
289
290 /*
291 * This check also prevents passing a zero-length array to qsort(),
292 * which is a problem on some platforms.
293 */
294 if (dir->sorted == dir->nr)
295 return;
296
297 QSORT(dir->entries, dir->nr, ref_entry_cmp);
298
299 /* Remove any duplicates: */
300 for (i = 0, j = 0; j < dir->nr; j++) {
301 struct ref_entry *entry = dir->entries[j];
302 if (last && is_dup_ref(last, entry))
303 free_ref_entry(entry);
304 else
305 last = dir->entries[i++] = entry;
306 }
307 dir->sorted = dir->nr = i;
308 }
309
310 int do_for_each_entry_in_dir(struct ref_dir *dir,
311 each_ref_entry_fn fn, void *cb_data)
312 {
313 int i;
314 assert(dir->sorted == dir->nr);
315 for (i = 0; i < dir->nr; i++) {
316 struct ref_entry *entry = dir->entries[i];
317 int retval;
318 if (entry->flag & REF_DIR) {
319 struct ref_dir *subdir = get_ref_dir(entry);
320 sort_ref_dir(subdir);
321 retval = do_for_each_entry_in_dir(subdir, fn, cb_data);
322 } else {
323 retval = fn(entry, cb_data);
324 }
325 if (retval)
326 return retval;
327 }
328 return 0;
329 }
330
331 void prime_ref_dir(struct ref_dir *dir)
332 {
333 /*
334 * The hard work of loading loose refs is done by get_ref_dir(), so we
335 * just need to recurse through all of the sub-directories. We do not
336 * even need to care about sorting, as traversal order does not matter
337 * to us.
338 */
339 int i;
340 for (i = 0; i < dir->nr; i++) {
341 struct ref_entry *entry = dir->entries[i];
342 if (entry->flag & REF_DIR)
343 prime_ref_dir(get_ref_dir(entry));
344 }
345 }
346
347 /*
348 * A level in the reference hierarchy that is currently being iterated
349 * through.
350 */
351 struct cache_ref_iterator_level {
352 /*
353 * The ref_dir being iterated over at this level. The ref_dir
354 * is sorted before being stored here.
355 */
356 struct ref_dir *dir;
357
358 /*
359 * The index of the current entry within dir (which might
360 * itself be a directory). If index == -1, then the iteration
361 * hasn't yet begun. If index == dir->nr, then the iteration
362 * through this level is over.
363 */
364 int index;
365 };
366
367 /*
368 * Represent an iteration through a ref_dir in the memory cache. The
369 * iteration recurses through subdirectories.
370 */
371 struct cache_ref_iterator {
372 struct ref_iterator base;
373
374 /*
375 * The number of levels currently on the stack. This is always
376 * at least 1, because when it becomes zero the iteration is
377 * ended and this struct is freed.
378 */
379 size_t levels_nr;
380
381 /* The number of levels that have been allocated on the stack */
382 size_t levels_alloc;
383
384 /*
385 * A stack of levels. levels[0] is the uppermost level that is
386 * being iterated over in this iteration. (This is not
387 * necessary the top level in the references hierarchy. If we
388 * are iterating through a subtree, then levels[0] will hold
389 * the ref_dir for that subtree, and subsequent levels will go
390 * on from there.)
391 */
392 struct cache_ref_iterator_level *levels;
393 };
394
395 static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
396 {
397 struct cache_ref_iterator *iter =
398 (struct cache_ref_iterator *)ref_iterator;
399
400 while (1) {
401 struct cache_ref_iterator_level *level =
402 &iter->levels[iter->levels_nr - 1];
403 struct ref_dir *dir = level->dir;
404 struct ref_entry *entry;
405
406 if (level->index == -1)
407 sort_ref_dir(dir);
408
409 if (++level->index == level->dir->nr) {
410 /* This level is exhausted; pop up a level */
411 if (--iter->levels_nr == 0)
412 return ref_iterator_abort(ref_iterator);
413
414 continue;
415 }
416
417 entry = dir->entries[level->index];
418
419 if (entry->flag & REF_DIR) {
420 /* push down a level */
421 ALLOC_GROW(iter->levels, iter->levels_nr + 1,
422 iter->levels_alloc);
423
424 level = &iter->levels[iter->levels_nr++];
425 level->dir = get_ref_dir(entry);
426 level->index = -1;
427 } else {
428 iter->base.refname = entry->name;
429 iter->base.oid = &entry->u.value.oid;
430 iter->base.flags = entry->flag;
431 return ITER_OK;
432 }
433 }
434 }
435
436 enum peel_status peel_entry(struct ref_entry *entry, int repeel)
437 {
438 enum peel_status status;
439
440 if (entry->flag & REF_KNOWS_PEELED) {
441 if (repeel) {
442 entry->flag &= ~REF_KNOWS_PEELED;
443 oidclr(&entry->u.value.peeled);
444 } else {
445 return is_null_oid(&entry->u.value.peeled) ?
446 PEEL_NON_TAG : PEEL_PEELED;
447 }
448 }
449 if (entry->flag & REF_ISBROKEN)
450 return PEEL_BROKEN;
451 if (entry->flag & REF_ISSYMREF)
452 return PEEL_IS_SYMREF;
453
454 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
455 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
456 entry->flag |= REF_KNOWS_PEELED;
457 return status;
458 }
459
460 static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
461 struct object_id *peeled)
462 {
463 struct cache_ref_iterator *iter =
464 (struct cache_ref_iterator *)ref_iterator;
465 struct cache_ref_iterator_level *level;
466 struct ref_entry *entry;
467
468 level = &iter->levels[iter->levels_nr - 1];
469
470 if (level->index == -1)
471 die("BUG: peel called before advance for cache iterator");
472
473 entry = level->dir->entries[level->index];
474
475 if (peel_entry(entry, 0))
476 return -1;
477 oidcpy(peeled, &entry->u.value.peeled);
478 return 0;
479 }
480
481 static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
482 {
483 struct cache_ref_iterator *iter =
484 (struct cache_ref_iterator *)ref_iterator;
485
486 free(iter->levels);
487 base_ref_iterator_free(ref_iterator);
488 return ITER_DONE;
489 }
490
491 static struct ref_iterator_vtable cache_ref_iterator_vtable = {
492 cache_ref_iterator_advance,
493 cache_ref_iterator_peel,
494 cache_ref_iterator_abort
495 };
496
497 struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
498 {
499 struct cache_ref_iterator *iter;
500 struct ref_iterator *ref_iterator;
501 struct cache_ref_iterator_level *level;
502
503 iter = xcalloc(1, sizeof(*iter));
504 ref_iterator = &iter->base;
505 base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
506 ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
507
508 iter->levels_nr = 1;
509 level = &iter->levels[0];
510 level->index = -1;
511 level->dir = dir;
512
513 return ref_iterator;
514 }