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 }