glusterfs 中的字典查询

1 dict_t *
2 get_new_dict (void)
3 {
4         return get_new_dict_full (1);
5 }

 1 dict_t *
 2 get_new_dict_full (int size_hint)
 3 {
 4         dict_t *dict = mem_get0 (THIS->ctx->dict_pool);
 5 
 6         if (!dict) {
 7                 return NULL;
 8         }
 9 
10         dict->hash_size = size_hint;
11         if (size_hint == 1) {
12                 /*
13                  * This is the only case we ever see currently.  If we ever
14                  * need to support resizing the hash table, the resize function
15                  * will have to take into account the possibility that
16                  * "members" is not separately allocated (i.e. don‘t just call
17                  * realloc() blindly.
18                  */
19                 dict->members = &dict->members_internal;
20         }
21         else {
22                 /*
23                  * We actually need to allocate space for size_hint *pointers*
24                  * but we actually allocate space for one *structure*.  Since
25                  * a data_pair_t consists of five pointers, we‘re wasting four
26                  * pointers‘ worth for N=1, and will overrun what we allocated
27                  * for N>5.  If anybody ever starts using size_hint, we‘ll need
28                  * to fix this.
29                  */
30                 GF_ASSERT (size_hint <=
31                            (sizeof(data_pair_t) / sizeof(data_pair_t *)));
32                 dict->members = mem_get0 (THIS->ctx->dict_pair_pool);
33                 if (!dict->members) {
34                         mem_put (dict);
35                         return NULL;
36                 }
37         }
38 
39         LOCK_INIT (&dict->lock);
40 
41         return dict;
42 }