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                         return i;
  46
  47         if (gentle)
  48                 return -1;
  49
  50         die("invalid object type \"%s\"", str);
  51 }
  52
  53 /*
  54  * Return a numerical hash value between 0 and n-1 for the object with
  55  * the specified sha1.  n must be a power of 2.  Please note that the
  56  * return value is *not* consistent across computer architectures.
  57  */
  58 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
  59 {
  60         return sha1hash(sha1) & (n - 1);
  61 }
  62
  63 /*
  64  * Insert obj into the hash table hash, which has length size (which
  65  * must be a power of 2).  On collisions, simply overflow to the next
  66  * empty bucket.
  67  */
  68 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
  69 {
  70         unsigned int j = hash_obj(obj->sha1, size);
  71
  72         while (hash[j]) {
  73                 j++;
  74                 if (j >= size)
  75                         j = 0;
  76         }
  77         hash[j] = obj;
  78 }
  79
  80 /*
  81  * Look up the record for the given sha1 in the hash map stored in
  82  * obj_hash.  Return NULL if it was not found.
  83  */
  84 struct object *lookup_object(const unsigned char *sha1)
  85 {
  86         unsigned int i, first;
  87         struct object *obj;
  88
  89         if (!obj_hash)
  90                 return NULL;
  91
  92         first = i = hash_obj(sha1, obj_hash_size);
  93         while ((obj = obj_hash[i]) != NULL) {
  94                 if (!hashcmp(sha1, obj->sha1))
  95                         break;
  96                 i++;
  97                 if (i == obj_hash_size)
  98                         i = 0;
  99         }
 100         if (obj && i != first) {
 101                 /*
 102                  * Move object to where we started to look for it so
 103                  * that we do not need to walk the hash table the next
 104                  * time we look for it.
 105                  */
 106                 struct object *tmp = obj_hash[i];
 107                 obj_hash[i] = obj_hash[first];
 108                 obj_hash[first] = tmp;
 109         }
 110         return obj;
 111 }
 112
 113 /*
 114  * Increase the size of the hash map stored in obj_hash to the next
 115  * power of 2 (but at least 32).  Copy the existing values to the new
 116  * hash map.
 117  */
 118 static void grow_object_hash(void)
 119 {
 120         int i;
 121         /*
 122          * Note that this size must always be power-of-2 to match hash_obj
 123          * above.
 124          */
 125         int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
 126         struct object **new_hash;
 127
 128         new_hash = xcalloc(new_hash_size, sizeof(struct object *));
 129         for (i = 0; i < obj_hash_size; i++) {
 130                 struct object *obj = obj_hash[i];
 131                 if (!obj)
 132                         continue;
 133                 insert_obj_hash(obj, new_hash, new_hash_size);
 134         }
 135         free(obj_hash);
 136         obj_hash = new_hash;
 137         obj_hash_size = new_hash_size;
 138 }
 139
 140 void *create_object(const unsigned char *sha1, void *o)
 141 {
 142         struct object *obj = o;
 143
 144         obj->parsed = 0;
 145         obj->used = 0;
 146         obj->flags = 0;
 147         hashcpy(obj->sha1, 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                               sha1_to_hex(obj->sha1),
 171                               typename(obj->type), typename(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 unsigned char *sha1, 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(sha1);
 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(sha1);
 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(sha1);
 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(sha1);
 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", sha1_to_hex(sha1), type);
 229                 obj = NULL;
 230         }
 231         return obj;
 232 }
 233
 234 struct object *parse_object_or_die(const unsigned char *sha1,
 235                                    const char *name)
 236 {
 237         struct object *o = parse_object(sha1);
 238         if (o)
 239                 return o;
 240
 241         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
 242 }
 243
 244 struct object *parse_object(const unsigned char *sha1)
 245 {
 246         unsigned long size;
 247         enum object_type type;
 248         int eaten;
 249         const unsigned char *repl = lookup_replace_object(sha1);
 250         void *buffer;
 251         struct object *obj;
 252
 253         obj = lookup_object(sha1);
 254         if (obj && obj->parsed)
 255                 return obj;
 256
 257         if ((obj && obj->type == OBJ_BLOB) ||
 258             (!obj && has_sha1_file(sha1) &&
 259              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
 260                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
 261                         error("sha1 mismatch %s", sha1_to_hex(repl));
 262                         return NULL;
 263                 }
 264                 parse_blob_buffer(lookup_blob(sha1), NULL, 0);
 265                 return lookup_object(sha1);
 266         }
 267
 268         buffer = read_sha1_file(sha1, &type, &size);
 269         if (buffer) {
 270                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 271                         free(buffer);
 272                         error("sha1 mismatch %s", sha1_to_hex(repl));
 273                         return NULL;
 274                 }
 275
 276                 obj = parse_object_buffer(sha1, 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 static void add_object_array_with_mode_context(struct object *obj, const char *name,
 311                                                struct object_array *array,
 312                                                unsigned mode,
 313                                                struct object_context *context)
 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                 objects = xrealloc(objects, alloc * sizeof(*objects));
 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         entry->context = context;
 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_mode(obj, name, array, S_IFINVALID);
 343 }
 344
 345 void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
 346 {
 347         add_object_array_with_mode_context(obj, name, array, mode, NULL);
 348 }
 349
 350 void add_object_array_with_context(struct object *obj, const char *name, struct object_array *array, struct object_context *context)
 351 {
 352         if (context)
 353                 add_object_array_with_mode_context(obj, name, array, context->mode, context);
 354         else
 355                 add_object_array_with_mode_context(obj, name, array, S_IFINVALID, context);
 356 }
 357
 358 void object_array_filter(struct object_array *array,
 359                          object_array_each_func_t want, void *cb_data)
 360 {
 361         unsigned nr = array->nr, src, dst;
 362         struct object_array_entry *objects = array->objects;
 363
 364         for (src = dst = 0; src < nr; src++) {
 365                 if (want(&objects[src], cb_data)) {
 366                         if (src != dst)
 367                                 objects[dst] = objects[src];
 368                         dst++;
 369                 } else {
 370                         if (objects[src].name != object_array_slopbuf)
 371                                 free(objects[src].name);
 372                 }
 373         }
 374         array->nr = dst;
 375 }
 376
 377 /*
 378  * Return true iff array already contains an entry with name.
 379  */
 380 static int contains_name(struct object_array *array, const char *name)
 381 {
 382         unsigned nr = array->nr, i;
 383         struct object_array_entry *object = array->objects;
 384
 385         for (i = 0; i < nr; i++, object++)
 386                 if (!strcmp(object->name, name))
 387                         return 1;
 388         return 0;
 389 }
 390
 391 void object_array_remove_duplicates(struct object_array *array)
 392 {
 393         unsigned nr = array->nr, src;
 394         struct object_array_entry *objects = array->objects;
 395
 396         array->nr = 0;
 397         for (src = 0; src < nr; src++) {
 398                 if (!contains_name(array, objects[src].name)) {
 399                         if (src != array->nr)
 400                                 objects[array->nr] = objects[src];
 401                         array->nr++;
 402                 } else {
 403                         if (objects[src].name != object_array_slopbuf)
 404                                 free(objects[src].name);
 405                 }
 406         }
 407 }
 408
 409 void clear_object_flags(unsigned flags)
 410 {
 411         int i;
 412
 413         for (i=0; i < obj_hash_size; i++) {
 414                 struct object *obj = obj_hash[i];
 415                 if (obj)
 416                         obj->flags &= ~flags;
 417         }
 418 }