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->sha1, 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->sha1))
  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                 struct object *tmp = obj_hash[i];
 108                 obj_hash[i] = obj_hash[first];
 109                 obj_hash[first] = tmp;
 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->used = 0;
 147         obj->flags = 0;
 148         hashcpy(obj->sha1, 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                               sha1_to_hex(obj->sha1),
 172                               typename(obj->type), typename(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 unsigned char *sha1, 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(sha1);
 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(sha1);
 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(sha1);
 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(sha1);
 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", sha1_to_hex(sha1), type);
 230                 obj = NULL;
 231         }
 232         return obj;
 233 }
 234
 235 struct object *parse_object_or_die(const unsigned char *sha1,
 236                                    const char *name)
 237 {
 238         struct object *o = parse_object(sha1);
 239         if (o)
 240                 return o;
 241
 242         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
 243 }
 244
 245 struct object *parse_object(const unsigned char *sha1)
 246 {
 247         unsigned long size;
 248         enum object_type type;
 249         int eaten;
 250         const unsigned char *repl = lookup_replace_object(sha1);
 251         void *buffer;
 252         struct object *obj;
 253
 254         obj = lookup_object(sha1);
 255         if (obj && obj->parsed)
 256                 return obj;
 257
 258         if ((obj && obj->type == OBJ_BLOB) ||
 259             (!obj && has_sha1_file(sha1) &&
 260              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
 261                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
 262                         error("sha1 mismatch %s", sha1_to_hex(repl));
 263                         return NULL;
 264                 }
 265                 parse_blob_buffer(lookup_blob(sha1), NULL, 0);
 266                 return lookup_object(sha1);
 267         }
 268
 269         buffer = read_sha1_file(sha1, &type, &size);
 270         if (buffer) {
 271                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 272                         free(buffer);
 273                         error("sha1 mismatch %s", sha1_to_hex(repl));
 274                         return NULL;
 275                 }
 276
 277                 obj = parse_object_buffer(sha1, 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 void object_array_filter(struct object_array *array,
 360                          object_array_each_func_t want, void *cb_data)
 361 {
 362         unsigned nr = array->nr, src, dst;
 363         struct object_array_entry *objects = array->objects;
 364
 365         for (src = dst = 0; src < nr; src++) {
 366                 if (want(&objects[src], cb_data)) {
 367                         if (src != dst)
 368                                 objects[dst] = objects[src];
 369                         dst++;
 370                 } else {
 371                         object_array_release_entry(&objects[src]);
 372                 }
 373         }
 374         array->nr = dst;
 375 }
 376
 377 void object_array_clear(struct object_array *array)
 378 {
 379         int i;
 380         for (i = 0; i < array->nr; i++)
 381                 object_array_release_entry(&array->objects[i]);
 382         free(array->objects);
 383         array->objects = NULL;
 384         array->nr = array->alloc = 0;
 385 }
 386
 387 /*
 388  * Return true iff array already contains an entry with name.
 389  */
 390 static int contains_name(struct object_array *array, const char *name)
 391 {
 392         unsigned nr = array->nr, i;
 393         struct object_array_entry *object = array->objects;
 394
 395         for (i = 0; i < nr; i++, object++)
 396                 if (!strcmp(object->name, name))
 397                         return 1;
 398         return 0;
 399 }
 400
 401 void object_array_remove_duplicates(struct object_array *array)
 402 {
 403         unsigned nr = array->nr, src;
 404         struct object_array_entry *objects = array->objects;
 405
 406         array->nr = 0;
 407         for (src = 0; src < nr; src++) {
 408                 if (!contains_name(array, objects[src].name)) {
 409                         if (src != array->nr)
 410                                 objects[array->nr] = objects[src];
 411                         array->nr++;
 412                 } else {
 413                         object_array_release_entry(&objects[src]);
 414                 }
 415         }
 416 }
 417
 418 void clear_object_flags(unsigned flags)
 419 {
 420         int i;
 421
 422         for (i=0; i < obj_hash_size; i++) {
 423                 struct object *obj = obj_hash[i];
 424                 if (obj)
 425                         obj->flags &= ~flags;
 426         }
 427 }