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