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 unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 184 {
 185         struct object_id oid;
 186         struct object *obj;
 187         *eaten_p = 0;
 188
 189         hashcpy(oid.hash, sha1);
 190
 191         obj = NULL;
 192         if (type == OBJ_BLOB) {
 193                 struct blob *blob = lookup_blob(&oid);
 194                 if (blob) {
 195                         if (parse_blob_buffer(blob, buffer, size))
 196                                 return NULL;
 197                         obj = &blob->object;
 198                 }
 199         } else if (type == OBJ_TREE) {
 200                 struct tree *tree = lookup_tree(sha1);
 201                 if (tree) {
 202                         obj = &tree->object;
 203                         if (!tree->buffer)
 204                                 tree->object.parsed = 0;
 205                         if (!tree->object.parsed) {
 206                                 if (parse_tree_buffer(tree, buffer, size))
 207                                         return NULL;
 208                                 *eaten_p = 1;
 209                         }
 210                 }
 211         } else if (type == OBJ_COMMIT) {
 212                 struct commit *commit = lookup_commit(&oid);
 213                 if (commit) {
 214                         if (parse_commit_buffer(commit, buffer, size))
 215                                 return NULL;
 216                         if (!get_cached_commit_buffer(commit, NULL)) {
 217                                 set_commit_buffer(commit, buffer, size);
 218                                 *eaten_p = 1;
 219                         }
 220                         obj = &commit->object;
 221                 }
 222         } else if (type == OBJ_TAG) {
 223                 struct tag *tag = lookup_tag(sha1);
 224                 if (tag) {
 225                         if (parse_tag_buffer(tag, buffer, size))
 226                                return NULL;
 227                         obj = &tag->object;
 228                 }
 229         } else {
 230                 warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
 231                 obj = NULL;
 232         }
 233         return obj;
 234 }
 235
 236 struct object *parse_object_or_die(const unsigned char *sha1,
 237                                    const char *name)
 238 {
 239         struct object *o = parse_object(sha1);
 240         if (o)
 241                 return o;
 242
 243         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
 244 }
 245
 246 struct object *parse_object(const unsigned char *sha1)
 247 {
 248         unsigned long size;
 249         enum object_type type;
 250         int eaten;
 251         const unsigned char *repl = lookup_replace_object(sha1);
 252         void *buffer;
 253         struct object *obj;
 254         struct object_id oid;
 255
 256         hashcpy(oid.hash, sha1);
 257
 258         obj = lookup_object(oid.hash);
 259         if (obj && obj->parsed)
 260                 return obj;
 261
 262         if ((obj && obj->type == OBJ_BLOB) ||
 263             (!obj && has_sha1_file(sha1) &&
 264              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
 265                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
 266                         error("sha1 mismatch %s", sha1_to_hex(repl));
 267                         return NULL;
 268                 }
 269                 parse_blob_buffer(lookup_blob(&oid), NULL, 0);
 270                 return lookup_object(sha1);
 271         }
 272
 273         buffer = read_sha1_file(sha1, &type, &size);
 274         if (buffer) {
 275                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 276                         free(buffer);
 277                         error("sha1 mismatch %s", sha1_to_hex(repl));
 278                         return NULL;
 279                 }
 280
 281                 obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
 282                 if (!eaten)
 283                         free(buffer);
 284                 return obj;
 285         }
 286         return NULL;
 287 }
 288
 289 struct object_list *object_list_insert(struct object *item,
 290                                        struct object_list **list_p)
 291 {
 292         struct object_list *new_list = xmalloc(sizeof(struct object_list));
 293         new_list->item = item;
 294         new_list->next = *list_p;
 295         *list_p = new_list;
 296         return new_list;
 297 }
 298
 299 int object_list_contains(struct object_list *list, struct object *obj)
 300 {
 301         while (list) {
 302                 if (list->item == obj)
 303                         return 1;
 304                 list = list->next;
 305         }
 306         return 0;
 307 }
 308
 309 /*
 310  * A zero-length string to which object_array_entry::name can be
 311  * initialized without requiring a malloc/free.
 312  */
 313 static char object_array_slopbuf[1];
 314
 315 void add_object_array_with_path(struct object *obj, const char *name,
 316                                 struct object_array *array,
 317                                 unsigned mode, const char *path)
 318 {
 319         unsigned nr = array->nr;
 320         unsigned alloc = array->alloc;
 321         struct object_array_entry *objects = array->objects;
 322         struct object_array_entry *entry;
 323
 324         if (nr >= alloc) {
 325                 alloc = (alloc + 32) * 2;
 326                 REALLOC_ARRAY(objects, alloc);
 327                 array->alloc = alloc;
 328                 array->objects = objects;
 329         }
 330         entry = &objects[nr];
 331         entry->item = obj;
 332         if (!name)
 333                 entry->name = NULL;
 334         else if (!*name)
 335                 /* Use our own empty string instead of allocating one: */
 336                 entry->name = object_array_slopbuf;
 337         else
 338                 entry->name = xstrdup(name);
 339         entry->mode = mode;
 340         if (path)
 341                 entry->path = xstrdup(path);
 342         else
 343                 entry->path = NULL;
 344         array->nr = ++nr;
 345 }
 346
 347 void add_object_array(struct object *obj, const char *name, struct object_array *array)
 348 {
 349         add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
 350 }
 351
 352 /*
 353  * Free all memory associated with an entry; the result is
 354  * in an unspecified state and should not be examined.
 355  */
 356 static void object_array_release_entry(struct object_array_entry *ent)
 357 {
 358         if (ent->name != object_array_slopbuf)
 359                 free(ent->name);
 360         free(ent->path);
 361 }
 362
 363 void object_array_filter(struct object_array *array,
 364                          object_array_each_func_t want, void *cb_data)
 365 {
 366         unsigned nr = array->nr, src, dst;
 367         struct object_array_entry *objects = array->objects;
 368
 369         for (src = dst = 0; src < nr; src++) {
 370                 if (want(&objects[src], cb_data)) {
 371                         if (src != dst)
 372                                 objects[dst] = objects[src];
 373                         dst++;
 374                 } else {
 375                         object_array_release_entry(&objects[src]);
 376                 }
 377         }
 378         array->nr = dst;
 379 }
 380
 381 void object_array_clear(struct object_array *array)
 382 {
 383         int i;
 384         for (i = 0; i < array->nr; i++)
 385                 object_array_release_entry(&array->objects[i]);
 386         free(array->objects);
 387         array->objects = NULL;
 388         array->nr = array->alloc = 0;
 389 }
 390
 391 /*
 392  * Return true iff array already contains an entry with name.
 393  */
 394 static int contains_name(struct object_array *array, const char *name)
 395 {
 396         unsigned nr = array->nr, i;
 397         struct object_array_entry *object = array->objects;
 398
 399         for (i = 0; i < nr; i++, object++)
 400                 if (!strcmp(object->name, name))
 401                         return 1;
 402         return 0;
 403 }
 404
 405 void object_array_remove_duplicates(struct object_array *array)
 406 {
 407         unsigned nr = array->nr, src;
 408         struct object_array_entry *objects = array->objects;
 409
 410         array->nr = 0;
 411         for (src = 0; src < nr; src++) {
 412                 if (!contains_name(array, objects[src].name)) {
 413                         if (src != array->nr)
 414                                 objects[array->nr] = objects[src];
 415                         array->nr++;
 416                 } else {
 417                         object_array_release_entry(&objects[src]);
 418                 }
 419         }
 420 }
 421
 422 void clear_object_flags(unsigned flags)
 423 {
 424         int i;
 425
 426         for (i=0; i < obj_hash_size; i++) {
 427                 struct object *obj = obj_hash[i];
 428                 if (obj)
 429                         obj->flags &= ~flags;
 430         }
 431 }