Merge branch 'nd/commit-util-to-slab'
[git] / object.c
1 #include "cache.h"
2 #include "object.h"
3 #include "replace-object.h"
4 #include "blob.h"
5 #include "tree.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "object-store.h"
9 #include "packfile.h"
10
11 static struct object **obj_hash;
12 static int nr_objs, obj_hash_size;
13
14 unsigned int get_max_object_index(void)
15 {
16         return obj_hash_size;
17 }
18
19 struct object *get_indexed_object(unsigned int idx)
20 {
21         return obj_hash[idx];
22 }
23
24 static const char *object_type_strings[] = {
25         NULL,           /* OBJ_NONE = 0 */
26         "commit",       /* OBJ_COMMIT = 1 */
27         "tree",         /* OBJ_TREE = 2 */
28         "blob",         /* OBJ_BLOB = 3 */
29         "tag",          /* OBJ_TAG = 4 */
30 };
31
32 const char *type_name(unsigned int type)
33 {
34         if (type >= ARRAY_SIZE(object_type_strings))
35                 return NULL;
36         return object_type_strings[type];
37 }
38
39 int type_from_string_gently(const char *str, ssize_t len, int gentle)
40 {
41         int i;
42
43         if (len < 0)
44                 len = strlen(str);
45
46         for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
47                 if (!strncmp(str, object_type_strings[i], len) &&
48                     object_type_strings[i][len] == '\0')
49                         return i;
50
51         if (gentle)
52                 return -1;
53
54         die("invalid object type \"%s\"", str);
55 }
56
57 /*
58  * Return a numerical hash value between 0 and n-1 for the object with
59  * the specified sha1.  n must be a power of 2.  Please note that the
60  * return value is *not* consistent across computer architectures.
61  */
62 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
63 {
64         return sha1hash(sha1) & (n - 1);
65 }
66
67 /*
68  * Insert obj into the hash table hash, which has length size (which
69  * must be a power of 2).  On collisions, simply overflow to the next
70  * empty bucket.
71  */
72 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
73 {
74         unsigned int j = hash_obj(obj->oid.hash, size);
75
76         while (hash[j]) {
77                 j++;
78                 if (j >= size)
79                         j = 0;
80         }
81         hash[j] = obj;
82 }
83
84 /*
85  * Look up the record for the given sha1 in the hash map stored in
86  * obj_hash.  Return NULL if it was not found.
87  */
88 struct object *lookup_object(const unsigned char *sha1)
89 {
90         unsigned int i, first;
91         struct object *obj;
92
93         if (!obj_hash)
94                 return NULL;
95
96         first = i = hash_obj(sha1, obj_hash_size);
97         while ((obj = obj_hash[i]) != NULL) {
98                 if (!hashcmp(sha1, obj->oid.hash))
99                         break;
100                 i++;
101                 if (i == obj_hash_size)
102                         i = 0;
103         }
104         if (obj && i != first) {
105                 /*
106                  * Move object to where we started to look for it so
107                  * that we do not need to walk the hash table the next
108                  * time we look for it.
109                  */
110                 SWAP(obj_hash[i], obj_hash[first]);
111         }
112         return obj;
113 }
114
115 /*
116  * Increase the size of the hash map stored in obj_hash to the next
117  * power of 2 (but at least 32).  Copy the existing values to the new
118  * hash map.
119  */
120 static void grow_object_hash(void)
121 {
122         int i;
123         /*
124          * Note that this size must always be power-of-2 to match hash_obj
125          * above.
126          */
127         int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
128         struct object **new_hash;
129
130         new_hash = xcalloc(new_hash_size, sizeof(struct object *));
131         for (i = 0; i < obj_hash_size; i++) {
132                 struct object *obj = obj_hash[i];
133                 if (!obj)
134                         continue;
135                 insert_obj_hash(obj, new_hash, new_hash_size);
136         }
137         free(obj_hash);
138         obj_hash = new_hash;
139         obj_hash_size = new_hash_size;
140 }
141
142 void *create_object(const unsigned char *sha1, void *o)
143 {
144         struct object *obj = o;
145
146         obj->parsed = 0;
147         obj->flags = 0;
148         hashcpy(obj->oid.hash, sha1);
149
150         if (obj_hash_size - 1 <= nr_objs * 2)
151                 grow_object_hash();
152
153         insert_obj_hash(obj, obj_hash, obj_hash_size);
154         nr_objs++;
155         return obj;
156 }
157
158 void *object_as_type(struct object *obj, enum object_type type, int quiet)
159 {
160         if (obj->type == type)
161                 return obj;
162         else if (obj->type == OBJ_NONE) {
163                 if (type == OBJ_COMMIT)
164                         ((struct commit *)obj)->index = alloc_commit_index();
165                 obj->type = type;
166                 return obj;
167         }
168         else {
169                 if (!quiet)
170                         error("object %s is a %s, not a %s",
171                               oid_to_hex(&obj->oid),
172                               type_name(obj->type), type_name(type));
173                 return NULL;
174         }
175 }
176
177 struct object *lookup_unknown_object(const unsigned char *sha1)
178 {
179         struct object *obj = lookup_object(sha1);
180         if (!obj)
181                 obj = create_object(sha1, alloc_object_node());
182         return obj;
183 }
184
185 struct object *parse_object_buffer(const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
186 {
187         struct object *obj;
188         *eaten_p = 0;
189
190         obj = NULL;
191         if (type == OBJ_BLOB) {
192                 struct blob *blob = lookup_blob(oid);
193                 if (blob) {
194                         if (parse_blob_buffer(blob, buffer, size))
195                                 return NULL;
196                         obj = &blob->object;
197                 }
198         } else if (type == OBJ_TREE) {
199                 struct tree *tree = lookup_tree(oid);
200                 if (tree) {
201                         obj = &tree->object;
202                         if (!tree->buffer)
203                                 tree->object.parsed = 0;
204                         if (!tree->object.parsed) {
205                                 if (parse_tree_buffer(tree, buffer, size))
206                                         return NULL;
207                                 *eaten_p = 1;
208                         }
209                 }
210         } else if (type == OBJ_COMMIT) {
211                 struct commit *commit = lookup_commit(oid);
212                 if (commit) {
213                         if (parse_commit_buffer(commit, buffer, size))
214                                 return NULL;
215                         if (!get_cached_commit_buffer(commit, NULL)) {
216                                 set_commit_buffer(commit, buffer, size);
217                                 *eaten_p = 1;
218                         }
219                         obj = &commit->object;
220                 }
221         } else if (type == OBJ_TAG) {
222                 struct tag *tag = lookup_tag(oid);
223                 if (tag) {
224                         if (parse_tag_buffer(tag, buffer, size))
225                                return NULL;
226                         obj = &tag->object;
227                 }
228         } else {
229                 warning("object %s has unknown type id %d", oid_to_hex(oid), type);
230                 obj = NULL;
231         }
232         return obj;
233 }
234
235 struct object *parse_object_or_die(const struct object_id *oid,
236                                    const char *name)
237 {
238         struct object *o = parse_object(oid);
239         if (o)
240                 return o;
241
242         die(_("unable to parse object: %s"), name ? name : oid_to_hex(oid));
243 }
244
245 struct object *parse_object(const struct object_id *oid)
246 {
247         unsigned long size;
248         enum object_type type;
249         int eaten;
250         const struct object_id *repl = lookup_replace_object(the_repository, oid);
251         void *buffer;
252         struct object *obj;
253
254         obj = lookup_object(oid->hash);
255         if (obj && obj->parsed)
256                 return obj;
257
258         if ((obj && obj->type == OBJ_BLOB && has_object_file(oid)) ||
259             (!obj && has_object_file(oid) &&
260              oid_object_info(the_repository, oid, NULL) == OBJ_BLOB)) {
261                 if (check_object_signature(repl, NULL, 0, NULL) < 0) {
262                         error("sha1 mismatch %s", oid_to_hex(oid));
263                         return NULL;
264                 }
265                 parse_blob_buffer(lookup_blob(oid), NULL, 0);
266                 return lookup_object(oid->hash);
267         }
268
269         buffer = read_object_file(oid, &type, &size);
270         if (buffer) {
271                 if (check_object_signature(repl, buffer, size, type_name(type)) < 0) {
272                         free(buffer);
273                         error("sha1 mismatch %s", oid_to_hex(repl));
274                         return NULL;
275                 }
276
277                 obj = parse_object_buffer(oid, type, size, buffer, &eaten);
278                 if (!eaten)
279                         free(buffer);
280                 return obj;
281         }
282         return NULL;
283 }
284
285 struct object_list *object_list_insert(struct object *item,
286                                        struct object_list **list_p)
287 {
288         struct object_list *new_list = xmalloc(sizeof(struct object_list));
289         new_list->item = item;
290         new_list->next = *list_p;
291         *list_p = new_list;
292         return new_list;
293 }
294
295 int object_list_contains(struct object_list *list, struct object *obj)
296 {
297         while (list) {
298                 if (list->item == obj)
299                         return 1;
300                 list = list->next;
301         }
302         return 0;
303 }
304
305 /*
306  * A zero-length string to which object_array_entry::name can be
307  * initialized without requiring a malloc/free.
308  */
309 static char object_array_slopbuf[1];
310
311 void add_object_array_with_path(struct object *obj, const char *name,
312                                 struct object_array *array,
313                                 unsigned mode, const char *path)
314 {
315         unsigned nr = array->nr;
316         unsigned alloc = array->alloc;
317         struct object_array_entry *objects = array->objects;
318         struct object_array_entry *entry;
319
320         if (nr >= alloc) {
321                 alloc = (alloc + 32) * 2;
322                 REALLOC_ARRAY(objects, alloc);
323                 array->alloc = alloc;
324                 array->objects = objects;
325         }
326         entry = &objects[nr];
327         entry->item = obj;
328         if (!name)
329                 entry->name = NULL;
330         else if (!*name)
331                 /* Use our own empty string instead of allocating one: */
332                 entry->name = object_array_slopbuf;
333         else
334                 entry->name = xstrdup(name);
335         entry->mode = mode;
336         if (path)
337                 entry->path = xstrdup(path);
338         else
339                 entry->path = NULL;
340         array->nr = ++nr;
341 }
342
343 void add_object_array(struct object *obj, const char *name, struct object_array *array)
344 {
345         add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
346 }
347
348 /*
349  * Free all memory associated with an entry; the result is
350  * in an unspecified state and should not be examined.
351  */
352 static void object_array_release_entry(struct object_array_entry *ent)
353 {
354         if (ent->name != object_array_slopbuf)
355                 free(ent->name);
356         free(ent->path);
357 }
358
359 struct object *object_array_pop(struct object_array *array)
360 {
361         struct object *ret;
362
363         if (!array->nr)
364                 return NULL;
365
366         ret = array->objects[array->nr - 1].item;
367         object_array_release_entry(&array->objects[array->nr - 1]);
368         array->nr--;
369         return ret;
370 }
371
372 void object_array_filter(struct object_array *array,
373                          object_array_each_func_t want, void *cb_data)
374 {
375         unsigned nr = array->nr, src, dst;
376         struct object_array_entry *objects = array->objects;
377
378         for (src = dst = 0; src < nr; src++) {
379                 if (want(&objects[src], cb_data)) {
380                         if (src != dst)
381                                 objects[dst] = objects[src];
382                         dst++;
383                 } else {
384                         object_array_release_entry(&objects[src]);
385                 }
386         }
387         array->nr = dst;
388 }
389
390 void object_array_clear(struct object_array *array)
391 {
392         int i;
393         for (i = 0; i < array->nr; i++)
394                 object_array_release_entry(&array->objects[i]);
395         FREE_AND_NULL(array->objects);
396         array->nr = array->alloc = 0;
397 }
398
399 /*
400  * Return true iff array already contains an entry with name.
401  */
402 static int contains_name(struct object_array *array, const char *name)
403 {
404         unsigned nr = array->nr, i;
405         struct object_array_entry *object = array->objects;
406
407         for (i = 0; i < nr; i++, object++)
408                 if (!strcmp(object->name, name))
409                         return 1;
410         return 0;
411 }
412
413 void object_array_remove_duplicates(struct object_array *array)
414 {
415         unsigned nr = array->nr, src;
416         struct object_array_entry *objects = array->objects;
417
418         array->nr = 0;
419         for (src = 0; src < nr; src++) {
420                 if (!contains_name(array, objects[src].name)) {
421                         if (src != array->nr)
422                                 objects[array->nr] = objects[src];
423                         array->nr++;
424                 } else {
425                         object_array_release_entry(&objects[src]);
426                 }
427         }
428 }
429
430 void clear_object_flags(unsigned flags)
431 {
432         int i;
433
434         for (i=0; i < obj_hash_size; i++) {
435                 struct object *obj = obj_hash[i];
436                 if (obj)
437                         obj->flags &= ~flags;
438         }
439 }
440
441 void clear_commit_marks_all(unsigned int flags)
442 {
443         int i;
444
445         for (i = 0; i < obj_hash_size; i++) {
446                 struct object *obj = obj_hash[i];
447                 if (obj && obj->type == OBJ_COMMIT)
448                         obj->flags &= ~flags;
449         }
450 }
451
452 struct raw_object_store *raw_object_store_new(void)
453 {
454         struct raw_object_store *o = xmalloc(sizeof(*o));
455
456         memset(o, 0, sizeof(*o));
457         INIT_LIST_HEAD(&o->packed_git_mru);
458         return o;
459 }
460
461 static void free_alt_odb(struct alternate_object_database *alt)
462 {
463         strbuf_release(&alt->scratch);
464         oid_array_clear(&alt->loose_objects_cache);
465         free(alt);
466 }
467
468 static void free_alt_odbs(struct raw_object_store *o)
469 {
470         while (o->alt_odb_list) {
471                 struct alternate_object_database *next;
472
473                 next = o->alt_odb_list->next;
474                 free_alt_odb(o->alt_odb_list);
475                 o->alt_odb_list = next;
476         }
477 }
478
479 void raw_object_store_clear(struct raw_object_store *o)
480 {
481         FREE_AND_NULL(o->objectdir);
482         FREE_AND_NULL(o->alternate_db);
483
484         oidmap_free(o->replace_map, 1);
485         FREE_AND_NULL(o->replace_map);
486
487         free_alt_odbs(o);
488         o->alt_odb_tail = NULL;
489
490         INIT_LIST_HEAD(&o->packed_git_mru);
491         close_all_packs(o);
492         o->packed_git = NULL;
493 }