a0a756f24f33621bbe83cbe69b18eef6790edacf
[git/git.git] / object.c
1 #include "cache.h"
2 #include "object.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "object-store.h"
8 #include "packfile.h"
9
10 static struct object **obj_hash;
11 static int nr_objs, obj_hash_size;
12
13 unsigned int get_max_object_index(void)
14 {
15 return obj_hash_size;
16 }
17
18 struct object *get_indexed_object(unsigned int idx)
19 {
20 return obj_hash[idx];
21 }
22
23 static const char *object_type_strings[] = {
24 NULL, /* OBJ_NONE = 0 */
25 "commit", /* OBJ_COMMIT = 1 */
26 "tree", /* OBJ_TREE = 2 */
27 "blob", /* OBJ_BLOB = 3 */
28 "tag", /* OBJ_TAG = 4 */
29 };
30
31 const char *type_name(unsigned int type)
32 {
33 if (type >= ARRAY_SIZE(object_type_strings))
34 return NULL;
35 return object_type_strings[type];
36 }
37
38 int type_from_string_gently(const char *str, ssize_t len, int gentle)
39 {
40 int i;
41
42 if (len < 0)
43 len = strlen(str);
44
45 for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
46 if (!strncmp(str, object_type_strings[i], len) &&
47 object_type_strings[i][len] == '\0')
48 return i;
49
50 if (gentle)
51 return -1;
52
53 die("invalid object type \"%s\"", str);
54 }
55
56 /*
57 * Return a numerical hash value between 0 and n-1 for the object with
58 * the specified sha1. n must be a power of 2. Please note that the
59 * return value is *not* consistent across computer architectures.
60 */
61 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
62 {
63 return sha1hash(sha1) & (n - 1);
64 }
65
66 /*
67 * Insert obj into the hash table hash, which has length size (which
68 * must be a power of 2). On collisions, simply overflow to the next
69 * empty bucket.
70 */
71 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
72 {
73 unsigned int j = hash_obj(obj->oid.hash, size);
74
75 while (hash[j]) {
76 j++;
77 if (j >= size)
78 j = 0;
79 }
80 hash[j] = obj;
81 }
82
83 /*
84 * Look up the record for the given sha1 in the hash map stored in
85 * obj_hash. Return NULL if it was not found.
86 */
87 struct object *lookup_object(const unsigned char *sha1)
88 {
89 unsigned int i, first;
90 struct object *obj;
91
92 if (!obj_hash)
93 return NULL;
94
95 first = i = hash_obj(sha1, obj_hash_size);
96 while ((obj = obj_hash[i]) != NULL) {
97 if (!hashcmp(sha1, obj->oid.hash))
98 break;
99 i++;
100 if (i == obj_hash_size)
101 i = 0;
102 }
103 if (obj && i != first) {
104 /*
105 * Move object to where we started to look for it so
106 * that we do not need to walk the hash table the next
107 * time we look for it.
108 */
109 SWAP(obj_hash[i], obj_hash[first]);
110 }
111 return obj;
112 }
113
114 /*
115 * Increase the size of the hash map stored in obj_hash to the next
116 * power of 2 (but at least 32). Copy the existing values to the new
117 * hash map.
118 */
119 static void grow_object_hash(void)
120 {
121 int i;
122 /*
123 * Note that this size must always be power-of-2 to match hash_obj
124 * above.
125 */
126 int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
127 struct object **new_hash;
128
129 new_hash = xcalloc(new_hash_size, sizeof(struct object *));
130 for (i = 0; i < obj_hash_size; i++) {
131 struct object *obj = obj_hash[i];
132 if (!obj)
133 continue;
134 insert_obj_hash(obj, new_hash, new_hash_size);
135 }
136 free(obj_hash);
137 obj_hash = new_hash;
138 obj_hash_size = new_hash_size;
139 }
140
141 void *create_object(const unsigned char *sha1, void *o)
142 {
143 struct object *obj = o;
144
145 obj->parsed = 0;
146 obj->flags = 0;
147 hashcpy(obj->oid.hash, sha1);
148
149 if (obj_hash_size - 1 <= nr_objs * 2)
150 grow_object_hash();
151
152 insert_obj_hash(obj, obj_hash, obj_hash_size);
153 nr_objs++;
154 return obj;
155 }
156
157 void *object_as_type(struct object *obj, enum object_type type, int quiet)
158 {
159 if (obj->type == type)
160 return obj;
161 else if (obj->type == OBJ_NONE) {
162 if (type == OBJ_COMMIT)
163 ((struct commit *)obj)->index = alloc_commit_index();
164 obj->type = type;
165 return obj;
166 }
167 else {
168 if (!quiet)
169 error("object %s is a %s, not a %s",
170 oid_to_hex(&obj->oid),
171 type_name(obj->type), type_name(type));
172 return NULL;
173 }
174 }
175
176 struct object *lookup_unknown_object(const unsigned char *sha1)
177 {
178 struct object *obj = lookup_object(sha1);
179 if (!obj)
180 obj = create_object(sha1, alloc_object_node());
181 return obj;
182 }
183
184 struct object *parse_object_buffer(const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
185 {
186 struct object *obj;
187 *eaten_p = 0;
188
189 obj = NULL;
190 if (type == OBJ_BLOB) {
191 struct blob *blob = lookup_blob(oid);
192 if (blob) {
193 if (parse_blob_buffer(blob, buffer, size))
194 return NULL;
195 obj = &blob->object;
196 }
197 } else if (type == OBJ_TREE) {
198 struct tree *tree = lookup_tree(oid);
199 if (tree) {
200 obj = &tree->object;
201 if (!tree->buffer)
202 tree->object.parsed = 0;
203 if (!tree->object.parsed) {
204 if (parse_tree_buffer(tree, buffer, size))
205 return NULL;
206 *eaten_p = 1;
207 }
208 }
209 } else if (type == OBJ_COMMIT) {
210 struct commit *commit = lookup_commit(oid);
211 if (commit) {
212 if (parse_commit_buffer(commit, buffer, size))
213 return NULL;
214 if (!get_cached_commit_buffer(commit, NULL)) {
215 set_commit_buffer(commit, buffer, size);
216 *eaten_p = 1;
217 }
218 obj = &commit->object;
219 }
220 } else if (type == OBJ_TAG) {
221 struct tag *tag = lookup_tag(oid);
222 if (tag) {
223 if (parse_tag_buffer(tag, buffer, size))
224 return NULL;
225 obj = &tag->object;
226 }
227 } else {
228 warning("object %s has unknown type id %d", oid_to_hex(oid), type);
229 obj = NULL;
230 }
231 return obj;
232 }
233
234 struct object *parse_object_or_die(const struct object_id *oid,
235 const char *name)
236 {
237 struct object *o = parse_object(oid);
238 if (o)
239 return o;
240
241 die(_("unable to parse object: %s"), name ? name : oid_to_hex(oid));
242 }
243
244 struct object *parse_object(const struct object_id *oid)
245 {
246 unsigned long size;
247 enum object_type type;
248 int eaten;
249 const struct object_id *repl = lookup_replace_object(oid);
250 void *buffer;
251 struct object *obj;
252
253 obj = lookup_object(oid->hash);
254 if (obj && obj->parsed)
255 return obj;
256
257 if ((obj && obj->type == OBJ_BLOB && has_object_file(oid)) ||
258 (!obj && has_object_file(oid) &&
259 oid_object_info(oid, NULL) == OBJ_BLOB)) {
260 if (check_object_signature(repl, NULL, 0, NULL) < 0) {
261 error("sha1 mismatch %s", oid_to_hex(oid));
262 return NULL;
263 }
264 parse_blob_buffer(lookup_blob(oid), NULL, 0);
265 return lookup_object(oid->hash);
266 }
267
268 buffer = read_object_file(oid, &type, &size);
269 if (buffer) {
270 if (check_object_signature(repl, buffer, size, type_name(type)) < 0) {
271 free(buffer);
272 error("sha1 mismatch %s", oid_to_hex(repl));
273 return NULL;
274 }
275
276 obj = parse_object_buffer(oid, type, size, buffer, &eaten);
277 if (!eaten)
278 free(buffer);
279 return obj;
280 }
281 return NULL;
282 }
283
284 struct object_list *object_list_insert(struct object *item,
285 struct object_list **list_p)
286 {
287 struct object_list *new_list = xmalloc(sizeof(struct object_list));
288 new_list->item = item;
289 new_list->next = *list_p;
290 *list_p = new_list;
291 return new_list;
292 }
293
294 int object_list_contains(struct object_list *list, struct object *obj)
295 {
296 while (list) {
297 if (list->item == obj)
298 return 1;
299 list = list->next;
300 }
301 return 0;
302 }
303
304 /*
305 * A zero-length string to which object_array_entry::name can be
306 * initialized without requiring a malloc/free.
307 */
308 static char object_array_slopbuf[1];
309
310 void add_object_array_with_path(struct object *obj, const char *name,
311 struct object_array *array,
312 unsigned mode, const char *path)
313 {
314 unsigned nr = array->nr;
315 unsigned alloc = array->alloc;
316 struct object_array_entry *objects = array->objects;
317 struct object_array_entry *entry;
318
319 if (nr >= alloc) {
320 alloc = (alloc + 32) * 2;
321 REALLOC_ARRAY(objects, alloc);
322 array->alloc = alloc;
323 array->objects = objects;
324 }
325 entry = &objects[nr];
326 entry->item = obj;
327 if (!name)
328 entry->name = NULL;
329 else if (!*name)
330 /* Use our own empty string instead of allocating one: */
331 entry->name = object_array_slopbuf;
332 else
333 entry->name = xstrdup(name);
334 entry->mode = mode;
335 if (path)
336 entry->path = xstrdup(path);
337 else
338 entry->path = NULL;
339 array->nr = ++nr;
340 }
341
342 void add_object_array(struct object *obj, const char *name, struct object_array *array)
343 {
344 add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
345 }
346
347 /*
348 * Free all memory associated with an entry; the result is
349 * in an unspecified state and should not be examined.
350 */
351 static void object_array_release_entry(struct object_array_entry *ent)
352 {
353 if (ent->name != object_array_slopbuf)
354 free(ent->name);
355 free(ent->path);
356 }
357
358 struct object *object_array_pop(struct object_array *array)
359 {
360 struct object *ret;
361
362 if (!array->nr)
363 return NULL;
364
365 ret = array->objects[array->nr - 1].item;
366 object_array_release_entry(&array->objects[array->nr - 1]);
367 array->nr--;
368 return ret;
369 }
370
371 void object_array_filter(struct object_array *array,
372 object_array_each_func_t want, void *cb_data)
373 {
374 unsigned nr = array->nr, src, dst;
375 struct object_array_entry *objects = array->objects;
376
377 for (src = dst = 0; src < nr; src++) {
378 if (want(&objects[src], cb_data)) {
379 if (src != dst)
380 objects[dst] = objects[src];
381 dst++;
382 } else {
383 object_array_release_entry(&objects[src]);
384 }
385 }
386 array->nr = dst;
387 }
388
389 void object_array_clear(struct object_array *array)
390 {
391 int i;
392 for (i = 0; i < array->nr; i++)
393 object_array_release_entry(&array->objects[i]);
394 FREE_AND_NULL(array->objects);
395 array->nr = array->alloc = 0;
396 }
397
398 /*
399 * Return true iff array already contains an entry with name.
400 */
401 static int contains_name(struct object_array *array, const char *name)
402 {
403 unsigned nr = array->nr, i;
404 struct object_array_entry *object = array->objects;
405
406 for (i = 0; i < nr; i++, object++)
407 if (!strcmp(object->name, name))
408 return 1;
409 return 0;
410 }
411
412 void object_array_remove_duplicates(struct object_array *array)
413 {
414 unsigned nr = array->nr, src;
415 struct object_array_entry *objects = array->objects;
416
417 array->nr = 0;
418 for (src = 0; src < nr; src++) {
419 if (!contains_name(array, objects[src].name)) {
420 if (src != array->nr)
421 objects[array->nr] = objects[src];
422 array->nr++;
423 } else {
424 object_array_release_entry(&objects[src]);
425 }
426 }
427 }
428
429 void clear_object_flags(unsigned flags)
430 {
431 int i;
432
433 for (i=0; i < obj_hash_size; i++) {
434 struct object *obj = obj_hash[i];
435 if (obj)
436 obj->flags &= ~flags;
437 }
438 }
439
440 void clear_commit_marks_all(unsigned int flags)
441 {
442 int i;
443
444 for (i = 0; i < obj_hash_size; i++) {
445 struct object *obj = obj_hash[i];
446 if (obj && obj->type == OBJ_COMMIT)
447 obj->flags &= ~flags;
448 }
449 }
450
451 struct raw_object_store *raw_object_store_new(void)
452 {
453 struct raw_object_store *o = xmalloc(sizeof(*o));
454
455 memset(o, 0, sizeof(*o));
456 INIT_LIST_HEAD(&o->packed_git_mru);
457 return o;
458 }
459
460 static void free_alt_odb(struct alternate_object_database *alt)
461 {
462 strbuf_release(&alt->scratch);
463 oid_array_clear(&alt->loose_objects_cache);
464 free(alt);
465 }
466
467 static void free_alt_odbs(struct raw_object_store *o)
468 {
469 while (o->alt_odb_list) {
470 struct alternate_object_database *next;
471
472 next = o->alt_odb_list->next;
473 free_alt_odb(o->alt_odb_list);
474 o->alt_odb_list = next;
475 }
476 }
477
478 void raw_object_store_clear(struct raw_object_store *o)
479 {
480 FREE_AND_NULL(o->objectdir);
481 FREE_AND_NULL(o->alternate_db);
482
483 free_alt_odbs(o);
484 o->alt_odb_tail = NULL;
485
486 INIT_LIST_HEAD(&o->packed_git_mru);
487 close_all_packs(o);
488 o->packed_git = NULL;
489 }