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