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(const char *str)
  37 {
  38         int i;
  39
  40         for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
  41                 if (!strcmp(str, object_type_strings[i]))
  42                         return i;
  43         die("invalid object type \"%s\"", str);
  44 }
  45
  46 /*
  47  * Return a numerical hash value between 0 and n-1 for the object with
  48  * the specified sha1.  n must be a power of 2.  Please note that the
  49  * return value is *not* consistent across computer architectures.
  50  */
  51 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
  52 {
  53         return sha1hash(sha1) & (n - 1);
  54 }
  55
  56 /*
  57  * Insert obj into the hash table hash, which has length size (which
  58  * must be a power of 2).  On collisions, simply overflow to the next
  59  * empty bucket.
  60  */
  61 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
  62 {
  63         unsigned int j = hash_obj(obj->sha1, size);
  64
  65         while (hash[j]) {
  66                 j++;
  67                 if (j >= size)
  68                         j = 0;
  69         }
  70         hash[j] = obj;
  71 }
  72
  73 /*
  74  * Look up the record for the given sha1 in the hash map stored in
  75  * obj_hash.  Return NULL if it was not found.
  76  */
  77 struct object *lookup_object(const unsigned char *sha1)
  78 {
  79         unsigned int i, first;
  80         struct object *obj;
  81
  82         if (!obj_hash)
  83                 return NULL;
  84
  85         first = i = hash_obj(sha1, obj_hash_size);
  86         while ((obj = obj_hash[i]) != NULL) {
  87                 if (!hashcmp(sha1, obj->sha1))
  88                         break;
  89                 i++;
  90                 if (i == obj_hash_size)
  91                         i = 0;
  92         }
  93         if (obj && i != first) {
  94                 /*
  95                  * Move object to where we started to look for it so
  96                  * that we do not need to walk the hash table the next
  97                  * time we look for it.
  98                  */
  99                 struct object *tmp = obj_hash[i];
 100                 obj_hash[i] = obj_hash[first];
 101                 obj_hash[first] = tmp;
 102         }
 103         return obj;
 104 }
 105
 106 /*
 107  * Increase the size of the hash map stored in obj_hash to the next
 108  * power of 2 (but at least 32).  Copy the existing values to the new
 109  * hash map.
 110  */
 111 static void grow_object_hash(void)
 112 {
 113         int i;
 114         /*
 115          * Note that this size must always be power-of-2 to match hash_obj
 116          * above.
 117          */
 118         int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
 119         struct object **new_hash;
 120
 121         new_hash = xcalloc(new_hash_size, sizeof(struct object *));
 122         for (i = 0; i < obj_hash_size; i++) {
 123                 struct object *obj = obj_hash[i];
 124                 if (!obj)
 125                         continue;
 126                 insert_obj_hash(obj, new_hash, new_hash_size);
 127         }
 128         free(obj_hash);
 129         obj_hash = new_hash;
 130         obj_hash_size = new_hash_size;
 131 }
 132
 133 void *create_object(const unsigned char *sha1, void *o)
 134 {
 135         struct object *obj = o;
 136
 137         obj->parsed = 0;
 138         obj->used = 0;
 139         obj->flags = 0;
 140         hashcpy(obj->sha1, sha1);
 141
 142         if (obj_hash_size - 1 <= nr_objs * 2)
 143                 grow_object_hash();
 144
 145         insert_obj_hash(obj, obj_hash, obj_hash_size);
 146         nr_objs++;
 147         return obj;
 148 }
 149
 150 void *object_as_type(struct object *obj, enum object_type type, int quiet)
 151 {
 152         if (obj->type == type)
 153                 return obj;
 154         else if (obj->type == OBJ_NONE) {
 155                 if (type == OBJ_COMMIT)
 156                         ((struct commit *)obj)->index = alloc_commit_index();
 157                 obj->type = type;
 158                 return obj;
 159         }
 160         else {
 161                 if (!quiet)
 162                         error("object %s is a %s, not a %s",
 163                               sha1_to_hex(obj->sha1),
 164                               typename(obj->type), typename(type));
 165                 return NULL;
 166         }
 167 }
 168
 169 struct object *lookup_unknown_object(const unsigned char *sha1)
 170 {
 171         struct object *obj = lookup_object(sha1);
 172         if (!obj)
 173                 obj = create_object(sha1, alloc_object_node());
 174         return obj;
 175 }
 176
 177 struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 178 {
 179         struct object *obj;
 180         *eaten_p = 0;
 181
 182         obj = NULL;
 183         if (type == OBJ_BLOB) {
 184                 struct blob *blob = lookup_blob(sha1);
 185                 if (blob) {
 186                         if (parse_blob_buffer(blob, buffer, size))
 187                                 return NULL;
 188                         obj = &blob->object;
 189                 }
 190         } else if (type == OBJ_TREE) {
 191                 struct tree *tree = lookup_tree(sha1);
 192                 if (tree) {
 193                         obj = &tree->object;
 194                         if (!tree->buffer)
 195                                 tree->object.parsed = 0;
 196                         if (!tree->object.parsed) {
 197                                 if (parse_tree_buffer(tree, buffer, size))
 198                                         return NULL;
 199                                 *eaten_p = 1;
 200                         }
 201                 }
 202         } else if (type == OBJ_COMMIT) {
 203                 struct commit *commit = lookup_commit(sha1);
 204                 if (commit) {
 205                         if (parse_commit_buffer(commit, buffer, size))
 206                                 return NULL;
 207                         if (!get_cached_commit_buffer(commit, NULL)) {
 208                                 set_commit_buffer(commit, buffer, size);
 209                                 *eaten_p = 1;
 210                         }
 211                         obj = &commit->object;
 212                 }
 213         } else if (type == OBJ_TAG) {
 214                 struct tag *tag = lookup_tag(sha1);
 215                 if (tag) {
 216                         if (parse_tag_buffer(tag, buffer, size))
 217                                return NULL;
 218                         obj = &tag->object;
 219                 }
 220         } else {
 221                 warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
 222                 obj = NULL;
 223         }
 224         return obj;
 225 }
 226
 227 struct object *parse_object_or_die(const unsigned char *sha1,
 228                                    const char *name)
 229 {
 230         struct object *o = parse_object(sha1);
 231         if (o)
 232                 return o;
 233
 234         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
 235 }
 236
 237 struct object *parse_object(const unsigned char *sha1)
 238 {
 239         unsigned long size;
 240         enum object_type type;
 241         int eaten;
 242         const unsigned char *repl = lookup_replace_object(sha1);
 243         void *buffer;
 244         struct object *obj;
 245
 246         obj = lookup_object(sha1);
 247         if (obj && obj->parsed)
 248                 return obj;
 249
 250         if ((obj && obj->type == OBJ_BLOB) ||
 251             (!obj && has_sha1_file(sha1) &&
 252              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
 253                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
 254                         error("sha1 mismatch %s", sha1_to_hex(repl));
 255                         return NULL;
 256                 }
 257                 parse_blob_buffer(lookup_blob(sha1), NULL, 0);
 258                 return lookup_object(sha1);
 259         }
 260
 261         buffer = read_sha1_file(sha1, &type, &size);
 262         if (buffer) {
 263                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
 264                         free(buffer);
 265                         error("sha1 mismatch %s", sha1_to_hex(repl));
 266                         return NULL;
 267                 }
 268
 269                 obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
 270                 if (!eaten)
 271                         free(buffer);
 272                 return obj;
 273         }
 274         return NULL;
 275 }
 276
 277 struct object_list *object_list_insert(struct object *item,
 278                                        struct object_list **list_p)
 279 {
 280         struct object_list *new_list = xmalloc(sizeof(struct object_list));
 281         new_list->item = item;
 282         new_list->next = *list_p;
 283         *list_p = new_list;
 284         return new_list;
 285 }
 286
 287 int object_list_contains(struct object_list *list, struct object *obj)
 288 {
 289         while (list) {
 290                 if (list->item == obj)
 291                         return 1;
 292                 list = list->next;
 293         }
 294         return 0;
 295 }
 296
 297 /*
 298  * A zero-length string to which object_array_entry::name can be
 299  * initialized without requiring a malloc/free.
 300  */
 301 static char object_array_slopbuf[1];
 302
 303 static void add_object_array_with_mode_context(struct object *obj, const char *name,
 304                                                struct object_array *array,
 305                                                unsigned mode,
 306                                                struct object_context *context)
 307 {
 308         unsigned nr = array->nr;
 309         unsigned alloc = array->alloc;
 310         struct object_array_entry *objects = array->objects;
 311         struct object_array_entry *entry;
 312
 313         if (nr >= alloc) {
 314                 alloc = (alloc + 32) * 2;
 315                 objects = xrealloc(objects, alloc * sizeof(*objects));
 316                 array->alloc = alloc;
 317                 array->objects = objects;
 318         }
 319         entry = &objects[nr];
 320         entry->item = obj;
 321         if (!name)
 322                 entry->name = NULL;
 323         else if (!*name)
 324                 /* Use our own empty string instead of allocating one: */
 325                 entry->name = object_array_slopbuf;
 326         else
 327                 entry->name = xstrdup(name);
 328         entry->mode = mode;
 329         entry->context = context;
 330         array->nr = ++nr;
 331 }
 332
 333 void add_object_array(struct object *obj, const char *name, struct object_array *array)
 334 {
 335         add_object_array_with_mode(obj, name, array, S_IFINVALID);
 336 }
 337
 338 void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
 339 {
 340         add_object_array_with_mode_context(obj, name, array, mode, NULL);
 341 }
 342
 343 void add_object_array_with_context(struct object *obj, const char *name, struct object_array *array, struct object_context *context)
 344 {
 345         if (context)
 346                 add_object_array_with_mode_context(obj, name, array, context->mode, context);
 347         else
 348                 add_object_array_with_mode_context(obj, name, array, S_IFINVALID, context);
 349 }
 350
 351 void object_array_filter(struct object_array *array,
 352                          object_array_each_func_t want, void *cb_data)
 353 {
 354         unsigned nr = array->nr, src, dst;
 355         struct object_array_entry *objects = array->objects;
 356
 357         for (src = dst = 0; src < nr; src++) {
 358                 if (want(&objects[src], cb_data)) {
 359                         if (src != dst)
 360                                 objects[dst] = objects[src];
 361                         dst++;
 362                 } else {
 363                         if (objects[src].name != object_array_slopbuf)
 364                                 free(objects[src].name);
 365                 }
 366         }
 367         array->nr = dst;
 368 }
 369
 370 /*
 371  * Return true iff array already contains an entry with name.
 372  */
 373 static int contains_name(struct object_array *array, const char *name)
 374 {
 375         unsigned nr = array->nr, i;
 376         struct object_array_entry *object = array->objects;
 377
 378         for (i = 0; i < nr; i++, object++)
 379                 if (!strcmp(object->name, name))
 380                         return 1;
 381         return 0;
 382 }
 383
 384 void object_array_remove_duplicates(struct object_array *array)
 385 {
 386         unsigned nr = array->nr, src;
 387         struct object_array_entry *objects = array->objects;
 388
 389         array->nr = 0;
 390         for (src = 0; src < nr; src++) {
 391                 if (!contains_name(array, objects[src].name)) {
 392                         if (src != array->nr)
 393                                 objects[array->nr] = objects[src];
 394                         array->nr++;
 395                 } else {
 396                         if (objects[src].name != object_array_slopbuf)
 397                                 free(objects[src].name);
 398                 }
 399         }
 400 }
 401
 402 void clear_object_flags(unsigned flags)
 403 {
 404         int i;
 405
 406         for (i=0; i < obj_hash_size; i++) {
 407                 struct object *obj = obj_hash[i];
 408                 if (obj)
 409                         obj->flags &= ~flags;
 410         }
 411 }