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->used = 0;
 145         obj->flags = 0;
 146         hashcpy(obj->oid.hash, sha1);
 147
 148         if (obj_hash_size - 1 <= nr_objs * 2)
 149                 grow_object_hash();
 150
 151         insert_obj_hash(obj, obj_hash, obj_hash_size);
 152         nr_objs++;
 153         return obj;
 154 }
 155
 156 void *object_as_type(struct object *obj, enum object_type type, int quiet)
 157 {
 158         if (obj->type == type)
 159                 return obj;
 160         else if (obj->type == OBJ_NONE) {
 161                 if (type == OBJ_COMMIT)
 162                         ((struct commit *)obj)->index = alloc_commit_index();
 163                 obj->type = type;
 164                 return obj;
 165         }
 166         else {
 167                 if (!quiet)
 168                         error("object %s is a %s, not a %s",
 169                               oid_to_hex(&obj->oid),
 170                               typename(obj->type), typename(type));
 171                 return NULL;
 172         }
 173 }
 174
 175 struct object *lookup_unknown_object(const unsigned char *sha1)
 176 {
 177         struct object *obj = lookup_object(sha1);
 178         if (!obj)
 179                 obj = create_object(sha1, alloc_object_node());
 180         return obj;
 181 }
 182
 183 struct object *parse_object_buffer(const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 184 {
 185         struct object *obj;
 186         *eaten_p = 0;
 187
 188         obj = NULL;
 189         if (type == OBJ_BLOB) {
 190                 struct blob *blob = lookup_blob(oid);
 191                 if (blob) {
 192                         if (parse_blob_buffer(blob, buffer, size))
 193                                 return NULL;
 194                         obj = &blob->object;
 195                 }
 196         } else if (type == OBJ_TREE) {
 197                 struct tree *tree = lookup_tree(oid);
 198                 if (tree) {
 199                         obj = &tree->object;
 200                         if (!tree->buffer)
 201                                 tree->object.parsed = 0;
 202                         if (!tree->object.parsed) {
 203                                 if (parse_tree_buffer(tree, buffer, size))
 204                                         return NULL;
 205                                 *eaten_p = 1;
 206                         }
 207                 }
 208         } else if (type == OBJ_COMMIT) {
 209                 struct commit *commit = lookup_commit(oid);
 210                 if (commit) {
 211                         if (parse_commit_buffer(commit, buffer, size))
 212                                 return NULL;
 213                         if (!get_cached_commit_buffer(commit, NULL)) {
 214                                 set_commit_buffer(commit, buffer, size);
 215                                 *eaten_p = 1;
 216                         }
 217                         obj = &commit->object;
 218                 }
 219         } else if (type == OBJ_TAG) {
 220                 struct tag *tag = lookup_tag(oid);
 221                 if (tag) {
 222                         if (parse_tag_buffer(tag, buffer, size))
 223                                return NULL;
 224                         obj = &tag->object;
 225                 }
 226         } else {
 227                 warning("object %s has unknown type id %d", oid_to_hex(oid), type);
 228                 obj = NULL;
 229         }
 230         return obj;
 231 }
 232
 233 struct object *parse_object_or_die(const struct object_id *oid,
 234                                    const char *name)
 235 {
 236         struct object *o = parse_object(oid);
 237         if (o)
 238                 return o;
 239
 240         die(_("unable to parse object: %s"), name ? name : oid_to_hex(oid));
 241 }
 242
 243 struct object *parse_object(const struct object_id *oid)
 244 {
 245         unsigned long size;
 246         enum object_type type;
 247         int eaten;
 248         const unsigned char *repl = lookup_replace_object(oid->hash);
 249         void *buffer;
 250         struct object *obj;
 251
 252         obj = lookup_object(oid->hash);
 253         if (obj && obj->parsed)
 254                 return obj;
 255
 256         if ((obj && obj->type == OBJ_BLOB) ||
 257             (!obj && has_object_file(oid) &&
 258              sha1_object_info(oid->hash, NULL) == OBJ_BLOB)) {
 259                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
 260                         error("sha1 mismatch %s", oid_to_hex(oid));
 261                         return NULL;
 262                 }
 263                 parse_blob_buffer(lookup_blob(oid), NULL, 0);
 264                 return lookup_object(oid->hash);
 265         }
 266
 267         buffer = read_sha1_file(oid->hash, &type, &size);
 268         if (buffer) {
 269                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 270                         free(buffer);
 271                         error("sha1 mismatch %s", sha1_to_hex(repl));
 272                         return NULL;
 273                 }
 274
 275                 obj = parse_object_buffer(oid, type, size, buffer, &eaten);
 276                 if (!eaten)
 277                         free(buffer);
 278                 return obj;
 279         }
 280         return NULL;
 281 }
 282
 283 struct object_list *object_list_insert(struct object *item,
 284                                        struct object_list **list_p)
 285 {
 286         struct object_list *new_list = xmalloc(sizeof(struct object_list));
 287         new_list->item = item;
 288         new_list->next = *list_p;
 289         *list_p = new_list;
 290         return new_list;
 291 }
 292
 293 int object_list_contains(struct object_list *list, struct object *obj)
 294 {
 295         while (list) {
 296                 if (list->item == obj)
 297                         return 1;
 298                 list = list->next;
 299         }
 300         return 0;
 301 }
 302
 303 /*
 304  * A zero-length string to which object_array_entry::name can be
 305  * initialized without requiring a malloc/free.
 306  */
 307 static char object_array_slopbuf[1];
 308
 309 void add_object_array_with_path(struct object *obj, const char *name,
 310                                 struct object_array *array,
 311                                 unsigned mode, const char *path)
 312 {
 313         unsigned nr = array->nr;
 314         unsigned alloc = array->alloc;
 315         struct object_array_entry *objects = array->objects;
 316         struct object_array_entry *entry;
 317
 318         if (nr >= alloc) {
 319                 alloc = (alloc + 32) * 2;
 320                 REALLOC_ARRAY(objects, alloc);
 321                 array->alloc = alloc;
 322                 array->objects = objects;
 323         }
 324         entry = &objects[nr];
 325         entry->item = obj;
 326         if (!name)
 327                 entry->name = NULL;
 328         else if (!*name)
 329                 /* Use our own empty string instead of allocating one: */
 330                 entry->name = object_array_slopbuf;
 331         else
 332                 entry->name = xstrdup(name);
 333         entry->mode = mode;
 334         if (path)
 335                 entry->path = xstrdup(path);
 336         else
 337                 entry->path = NULL;
 338         array->nr = ++nr;
 339 }
 340
 341 void add_object_array(struct object *obj, const char *name, struct object_array *array)
 342 {
 343         add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
 344 }
 345
 346 /*
 347  * Free all memory associated with an entry; the result is
 348  * in an unspecified state and should not be examined.
 349  */
 350 static void object_array_release_entry(struct object_array_entry *ent)
 351 {
 352         if (ent->name != object_array_slopbuf)
 353                 free(ent->name);
 354         free(ent->path);
 355 }
 356
 357 void object_array_filter(struct object_array *array,
 358                          object_array_each_func_t want, void *cb_data)
 359 {
 360         unsigned nr = array->nr, src, dst;
 361         struct object_array_entry *objects = array->objects;
 362
 363         for (src = dst = 0; src < nr; src++) {
 364                 if (want(&objects[src], cb_data)) {
 365                         if (src != dst)
 366                                 objects[dst] = objects[src];
 367                         dst++;
 368                 } else {
 369                         object_array_release_entry(&objects[src]);
 370                 }
 371         }
 372         array->nr = dst;
 373 }
 374
 375 void object_array_clear(struct object_array *array)
 376 {
 377         int i;
 378         for (i = 0; i < array->nr; i++)
 379                 object_array_release_entry(&array->objects[i]);
 380         free(array->objects);
 381         array->objects = NULL;
 382         array->nr = array->alloc = 0;
 383 }
 384
 385 /*
 386  * Return true iff array already contains an entry with name.
 387  */
 388 static int contains_name(struct object_array *array, const char *name)
 389 {
 390         unsigned nr = array->nr, i;
 391         struct object_array_entry *object = array->objects;
 392
 393         for (i = 0; i < nr; i++, object++)
 394                 if (!strcmp(object->name, name))
 395                         return 1;
 396         return 0;
 397 }
 398
 399 void object_array_remove_duplicates(struct object_array *array)
 400 {
 401         unsigned nr = array->nr, src;
 402         struct object_array_entry *objects = array->objects;
 403
 404         array->nr = 0;
 405         for (src = 0; src < nr; src++) {
 406                 if (!contains_name(array, objects[src].name)) {
 407                         if (src != array->nr)
 408                                 objects[array->nr] = objects[src];
 409                         array->nr++;
 410                 } else {
 411                         object_array_release_entry(&objects[src]);
 412                 }
 413         }
 414 }
 415
 416 void clear_object_flags(unsigned flags)
 417 {
 418         int i;
 419
 420         for (i=0; i < obj_hash_size; i++) {
 421                 struct object *obj = obj_hash[i];
 422                 if (obj)
 423                         obj->flags &= ~flags;
 424         }
 425 }