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
   8 static struct object **obj_hash;
   9 static int nr_objs, obj_hash_size;
  10
  11 unsigned int get_max_object_index(void)
  12 {
  13         return obj_hash_size;
  14 }
  15
  16 struct object *get_indexed_object(unsigned int idx)
  17 {
  18         return obj_hash[idx];
  19 }
  20
  21 static const char *object_type_strings[] = {
  22         NULL,           /* OBJ_NONE = 0 */
  23         "commit",       /* OBJ_COMMIT = 1 */
  24         "tree",         /* OBJ_TREE = 2 */
  25         "blob",         /* OBJ_BLOB = 3 */
  26         "tag",          /* OBJ_TAG = 4 */
  27 };
  28
  29 const char *typename(unsigned int type)
  30 {
  31         if (type >= ARRAY_SIZE(object_type_strings))
  32                 return NULL;
  33         return object_type_strings[type];
  34 }
  35
  36 int type_from_string_gently(const char *str, ssize_t len, int gentle)
  37 {
  38         int i;
  39
  40         if (len < 0)
  41                 len = strlen(str);
  42
  43         for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
  44                 if (!strncmp(str, object_type_strings[i], len) &&
  45                     object_type_strings[i][len] == '\0')
  46                         return i;
  47
  48         if (gentle)
  49                 return -1;
  50
  51         die("invalid object type \"%s\"", str);
  52 }
  53
  54 /*
  55  * Return a numerical hash value between 0 and n-1 for the object with
  56  * the specified sha1.  n must be a power of 2.  Please note that the
  57  * return value is *not* consistent across computer architectures.
  58  */
  59 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
  60 {
  61         return sha1hash(sha1) & (n - 1);
  62 }
  63
  64 /*
  65  * Insert obj into the hash table hash, which has length size (which
  66  * must be a power of 2).  On collisions, simply overflow to the next
  67  * empty bucket.
  68  */
  69 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
  70 {
  71         unsigned int j = hash_obj(obj->oid.hash, size);
  72
  73         while (hash[j]) {
  74                 j++;
  75                 if (j >= size)
  76                         j = 0;
  77         }
  78         hash[j] = obj;
  79 }
  80
  81 /*
  82  * Look up the record for the given sha1 in the hash map stored in
  83  * obj_hash.  Return NULL if it was not found.
  84  */
  85 struct object *lookup_object(const unsigned char *sha1)
  86 {
  87         unsigned int i, first;
  88         struct object *obj;
  89
  90         if (!obj_hash)
  91                 return NULL;
  92
  93         first = i = hash_obj(sha1, obj_hash_size);
  94         while ((obj = obj_hash[i]) != NULL) {
  95                 if (!hashcmp(sha1, obj->oid.hash))
  96                         break;
  97                 i++;
  98                 if (i == obj_hash_size)
  99                         i = 0;
 100         }
 101         if (obj && i != first) {
 102                 /*
 103                  * Move object to where we started to look for it so
 104                  * that we do not need to walk the hash table the next
 105                  * time we look for it.
 106                  */
 107                 SWAP(obj_hash[i], obj_hash[first]);
 108         }
 109         return obj;
 110 }
 111
 112 /*
 113  * Increase the size of the hash map stored in obj_hash to the next
 114  * power of 2 (but at least 32).  Copy the existing values to the new
 115  * hash map.
 116  */
 117 static void grow_object_hash(void)
 118 {
 119         int i;
 120         /*
 121          * Note that this size must always be power-of-2 to match hash_obj
 122          * above.
 123          */
 124         int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
 125         struct object **new_hash;
 126
 127         new_hash = xcalloc(new_hash_size, sizeof(struct object *));
 128         for (i = 0; i < obj_hash_size; i++) {
 129                 struct object *obj = obj_hash[i];
 130                 if (!obj)
 131                         continue;
 132                 insert_obj_hash(obj, new_hash, new_hash_size);
 133         }
 134         free(obj_hash);
 135         obj_hash = new_hash;
 136         obj_hash_size = new_hash_size;
 137 }
 138
 139 void *create_object(const unsigned char *sha1, void *o)
 140 {
 141         struct object *obj = o;
 142
 143         obj->parsed = 0;
 144         obj->flags = 0;
 145         hashcpy(obj->oid.hash, sha1);
 146
 147         if (obj_hash_size - 1 <= nr_objs * 2)
 148                 grow_object_hash();
 149
 150         insert_obj_hash(obj, obj_hash, obj_hash_size);
 151         nr_objs++;
 152         return obj;
 153 }
 154
 155 void *object_as_type(struct object *obj, enum object_type type, int quiet)
 156 {
 157         if (obj->type == type)
 158                 return obj;
 159         else if (obj->type == OBJ_NONE) {
 160                 if (type == OBJ_COMMIT)
 161                         ((struct commit *)obj)->index = alloc_commit_index();
 162                 obj->type = type;
 163                 return obj;
 164         }
 165         else {
 166                 if (!quiet)
 167                         error("object %s is a %s, not a %s",
 168                               oid_to_hex(&obj->oid),
 169                               typename(obj->type), typename(type));
 170                 return NULL;
 171         }
 172 }
 173
 174 struct object *lookup_unknown_object(const unsigned char *sha1)
 175 {
 176         struct object *obj = lookup_object(sha1);
 177         if (!obj)
 178                 obj = create_object(sha1, alloc_object_node());
 179         return obj;
 180 }
 181
 182 struct object *parse_object_buffer(const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 183 {
 184         struct object *obj;
 185         *eaten_p = 0;
 186
 187         obj = NULL;
 188         if (type == OBJ_BLOB) {
 189                 struct blob *blob = lookup_blob(oid);
 190                 if (blob) {
 191                         if (parse_blob_buffer(blob, buffer, size))
 192                                 return NULL;
 193                         obj = &blob->object;
 194                 }
 195         } else if (type == OBJ_TREE) {
 196                 struct tree *tree = lookup_tree(oid);
 197                 if (tree) {
 198                         obj = &tree->object;
 199                         if (!tree->buffer)
 200                                 tree->object.parsed = 0;
 201                         if (!tree->object.parsed) {
 202                                 if (parse_tree_buffer(tree, buffer, size))
 203                                         return NULL;
 204                                 *eaten_p = 1;
 205                         }
 206                 }
 207         } else if (type == OBJ_COMMIT) {
 208                 struct commit *commit = lookup_commit(oid);
 209                 if (commit) {
 210                         if (parse_commit_buffer(commit, buffer, size))
 211                                 return NULL;
 212                         if (!get_cached_commit_buffer(commit, NULL)) {
 213                                 set_commit_buffer(commit, buffer, size);
 214                                 *eaten_p = 1;
 215                         }
 216                         obj = &commit->object;
 217                 }
 218         } else if (type == OBJ_TAG) {
 219                 struct tag *tag = lookup_tag(oid);
 220                 if (tag) {
 221                         if (parse_tag_buffer(tag, buffer, size))
 222                                return NULL;
 223                         obj = &tag->object;
 224                 }
 225         } else {
 226                 warning("object %s has unknown type id %d", oid_to_hex(oid), type);
 227                 obj = NULL;
 228         }
 229         return obj;
 230 }
 231
 232 struct object *parse_object_or_die(const struct object_id *oid,
 233                                    const char *name)
 234 {
 235         struct object *o = parse_object(oid);
 236         if (o)
 237                 return o;
 238
 239         die(_("unable to parse object: %s"), name ? name : oid_to_hex(oid));
 240 }
 241
 242 struct object *parse_object(const struct object_id *oid)
 243 {
 244         unsigned long size;
 245         enum object_type type;
 246         int eaten;
 247         const unsigned char *repl = lookup_replace_object(oid->hash);
 248         void *buffer;
 249         struct object *obj;
 250
 251         obj = lookup_object(oid->hash);
 252         if (obj && obj->parsed)
 253                 return obj;
 254
 255         if ((obj && obj->type == OBJ_BLOB) ||
 256             (!obj && has_object_file(oid) &&
 257              sha1_object_info(oid->hash, NULL) == OBJ_BLOB)) {
 258                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
 259                         error("sha1 mismatch %s", oid_to_hex(oid));
 260                         return NULL;
 261                 }
 262                 parse_blob_buffer(lookup_blob(oid), NULL, 0);
 263                 return lookup_object(oid->hash);
 264         }
 265
 266         buffer = read_sha1_file(oid->hash, &type, &size);
 267         if (buffer) {
 268                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 269                         free(buffer);
 270                         error("sha1 mismatch %s", sha1_to_hex(repl));
 271                         return NULL;
 272                 }
 273
 274                 obj = parse_object_buffer(oid, type, size, buffer, &eaten);
 275                 if (!eaten)
 276                         free(buffer);
 277                 return obj;
 278         }
 279         return NULL;
 280 }
 281
 282 struct object_list *object_list_insert(struct object *item,
 283                                        struct object_list **list_p)
 284 {
 285         struct object_list *new_list = xmalloc(sizeof(struct object_list));
 286         new_list->item = item;
 287         new_list->next = *list_p;
 288         *list_p = new_list;
 289         return new_list;
 290 }
 291
 292 int object_list_contains(struct object_list *list, struct object *obj)
 293 {
 294         while (list) {
 295                 if (list->item == obj)
 296                         return 1;
 297                 list = list->next;
 298         }
 299         return 0;
 300 }
 301
 302 /*
 303  * A zero-length string to which object_array_entry::name can be
 304  * initialized without requiring a malloc/free.
 305  */
 306 static char object_array_slopbuf[1];
 307
 308 void add_object_array_with_path(struct object *obj, const char *name,
 309                                 struct object_array *array,
 310                                 unsigned mode, const char *path)
 311 {
 312         unsigned nr = array->nr;
 313         unsigned alloc = array->alloc;
 314         struct object_array_entry *objects = array->objects;
 315         struct object_array_entry *entry;
 316
 317         if (nr >= alloc) {
 318                 alloc = (alloc + 32) * 2;
 319                 REALLOC_ARRAY(objects, alloc);
 320                 array->alloc = alloc;
 321                 array->objects = objects;
 322         }
 323         entry = &objects[nr];
 324         entry->item = obj;
 325         if (!name)
 326                 entry->name = NULL;
 327         else if (!*name)
 328                 /* Use our own empty string instead of allocating one: */
 329                 entry->name = object_array_slopbuf;
 330         else
 331                 entry->name = xstrdup(name);
 332         entry->mode = mode;
 333         if (path)
 334                 entry->path = xstrdup(path);
 335         else
 336                 entry->path = NULL;
 337         array->nr = ++nr;
 338 }
 339
 340 void add_object_array(struct object *obj, const char *name, struct object_array *array)
 341 {
 342         add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
 343 }
 344
 345 /*
 346  * Free all memory associated with an entry; the result is
 347  * in an unspecified state and should not be examined.
 348  */
 349 static void object_array_release_entry(struct object_array_entry *ent)
 350 {
 351         if (ent->name != object_array_slopbuf)
 352                 free(ent->name);
 353         free(ent->path);
 354 }
 355
 356 struct object *object_array_pop(struct object_array *array)
 357 {
 358         struct object *ret;
 359
 360         if (!array->nr)
 361                 return NULL;
 362
 363         ret = array->objects[array->nr - 1].item;
 364         object_array_release_entry(&array->objects[array->nr - 1]);
 365         array->nr--;
 366         return ret;
 367 }
 368
 369 void object_array_filter(struct object_array *array,
 370                          object_array_each_func_t want, void *cb_data)
 371 {
 372         unsigned nr = array->nr, src, dst;
 373         struct object_array_entry *objects = array->objects;
 374
 375         for (src = dst = 0; src < nr; src++) {
 376                 if (want(&objects[src], cb_data)) {
 377                         if (src != dst)
 378                                 objects[dst] = objects[src];
 379                         dst++;
 380                 } else {
 381                         object_array_release_entry(&objects[src]);
 382                 }
 383         }
 384         array->nr = dst;
 385 }
 386
 387 void object_array_clear(struct object_array *array)
 388 {
 389         int i;
 390         for (i = 0; i < array->nr; i++)
 391                 object_array_release_entry(&array->objects[i]);
 392         FREE_AND_NULL(array->objects);
 393         array->nr = array->alloc = 0;
 394 }
 395
 396 /*
 397  * Return true iff array already contains an entry with name.
 398  */
 399 static int contains_name(struct object_array *array, const char *name)
 400 {
 401         unsigned nr = array->nr, i;
 402         struct object_array_entry *object = array->objects;
 403
 404         for (i = 0; i < nr; i++, object++)
 405                 if (!strcmp(object->name, name))
 406                         return 1;
 407         return 0;
 408 }
 409
 410 void object_array_remove_duplicates(struct object_array *array)
 411 {
 412         unsigned nr = array->nr, src;
 413         struct object_array_entry *objects = array->objects;
 414
 415         array->nr = 0;
 416         for (src = 0; src < nr; src++) {
 417                 if (!contains_name(array, objects[src].name)) {
 418                         if (src != array->nr)
 419                                 objects[array->nr] = objects[src];
 420                         array->nr++;
 421                 } else {
 422                         object_array_release_entry(&objects[src]);
 423                 }
 424         }
 425 }
 426
 427 void clear_object_flags(unsigned flags)
 428 {
 429         int i;
 430
 431         for (i=0; i < obj_hash_size; i++) {
 432                 struct object *obj = obj_hash[i];
 433                 if (obj)
 434                         obj->flags &= ~flags;
 435         }
 436 }