src/dictionary.c

   1 #include "common.h"
   2
   3 // ----------------------------------------------------------------------------
   4 // dictionary statistics
   5
   6 static inline void NETDATA_DICTIONARY_STATS_INSERTS_PLUS1(DICTIONARY *dict) {
   7     if(likely(dict->stats))
   8         dict->stats->inserts++;
   9 }
  10 static inline void NETDATA_DICTIONARY_STATS_DELETES_PLUS1(DICTIONARY *dict) {
  11     if(likely(dict->stats))
  12         dict->stats->deletes++;
  13 }
  14 static inline void NETDATA_DICTIONARY_STATS_SEARCHES_PLUS1(DICTIONARY *dict) {
  15     if(likely(dict->stats))
  16         dict->stats->searches++;
  17 }
  18 static inline void NETDATA_DICTIONARY_STATS_ENTRIES_PLUS1(DICTIONARY *dict) {
  19     if(likely(dict->stats))
  20         dict->stats->entries++;
  21 }
  22 static inline void NETDATA_DICTIONARY_STATS_ENTRIES_MINUS1(DICTIONARY *dict) {
  23     if(likely(dict->stats))
  24         dict->stats->entries--;
  25 }
  26
  27
  28 // ----------------------------------------------------------------------------
  29 // dictionary locks
  30
  31 static inline void dictionary_read_lock(DICTIONARY *dict) {
  32     if(likely(dict->rwlock)) {
  33         // debug(D_DICTIONARY, "Dictionary READ lock");
  34         pthread_rwlock_rdlock(dict->rwlock);
  35     }
  36 }
  37
  38 static inline void dictionary_write_lock(DICTIONARY *dict) {
  39     if(likely(dict->rwlock)) {
  40         // debug(D_DICTIONARY, "Dictionary WRITE lock");
  41         pthread_rwlock_wrlock(dict->rwlock);
  42     }
  43 }
  44
  45 static inline void dictionary_unlock(DICTIONARY *dict) {
  46     if(likely(dict->rwlock)) {
  47         // debug(D_DICTIONARY, "Dictionary UNLOCK lock");
  48         pthread_rwlock_unlock(dict->rwlock);
  49     }
  50 }
  51
  52
  53 // ----------------------------------------------------------------------------
  54 // avl index
  55
  56 static int name_value_compare(void* a, void* b) {
  57     if(((NAME_VALUE *)a)->hash < ((NAME_VALUE *)b)->hash) return -1;
  58     else if(((NAME_VALUE *)a)->hash > ((NAME_VALUE *)b)->hash) return 1;
  59     else return strcmp(((NAME_VALUE *)a)->name, ((NAME_VALUE *)b)->name);
  60 }
  61
  62 #define dictionary_name_value_index_add_nolock(dict, nv) do { NETDATA_DICTIONARY_STATS_INSERTS_PLUS1(dict); avl_insert(&((dict)->values_index), (avl *)(nv)); } while(0)
  63 #define dictionary_name_value_index_del_nolock(dict, nv) do { NETDATA_DICTIONARY_STATS_DELETES_PLUS1(dict); avl_remove(&(dict->values_index), (avl *)(nv)); } while(0)
  64
  65 static inline NAME_VALUE *dictionary_name_value_index_find_nolock(DICTIONARY *dict, const char *name, uint32_t hash) {
  66     NAME_VALUE tmp;
  67     tmp.hash = (hash)?hash:simple_hash(name);
  68     tmp.name = (char *)name;
  69
  70     NETDATA_DICTIONARY_STATS_SEARCHES_PLUS1(dict);
  71     return (NAME_VALUE *)avl_search(&(dict->values_index), (avl *) &tmp);
  72 }
  73
  74 // ----------------------------------------------------------------------------
  75 // internal methods
  76
  77 static NAME_VALUE *dictionary_name_value_create_nolock(DICTIONARY *dict, const char *name, void *value, size_t value_len, uint32_t hash) {
  78     debug(D_DICTIONARY, "Creating name value entry for name '%s'.", name);
  79
  80     NAME_VALUE *nv = callocz(1, sizeof(NAME_VALUE));
  81
  82     if(dict->flags & DICTIONARY_FLAG_NAME_LINK_DONT_CLONE)
  83         nv->name = (char *)name;
  84     else {
  85         nv->name = strdupz(name);
  86     }
  87
  88     nv->hash = (hash)?hash:simple_hash(nv->name);
  89
  90     if(dict->flags & DICTIONARY_FLAG_VALUE_LINK_DONT_CLONE)
  91         nv->value = value;
  92     else {
  93         nv->value = mallocz(value_len);
  94         memcpy(nv->value, value, value_len);
  95     }
  96
  97     // index it
  98     dictionary_name_value_index_add_nolock(dict, nv);
  99     NETDATA_DICTIONARY_STATS_ENTRIES_PLUS1(dict);
 100
 101     return nv;
 102 }
 103
 104 static void dictionary_name_value_destroy_nolock(DICTIONARY *dict, NAME_VALUE *nv) {
 105     debug(D_DICTIONARY, "Destroying name value entry for name '%s'.", nv->name);
 106
 107     dictionary_name_value_index_del_nolock(dict, nv);
 108
 109     NETDATA_DICTIONARY_STATS_ENTRIES_MINUS1(dict);
 110
 111     if(!(dict->flags & DICTIONARY_FLAG_VALUE_LINK_DONT_CLONE)) {
 112         debug(D_REGISTRY, "Dictionary freeing value of '%s'", nv->name);
 113         freez(nv->value);
 114     }
 115
 116     if(!(dict->flags & DICTIONARY_FLAG_NAME_LINK_DONT_CLONE)) {
 117         debug(D_REGISTRY, "Dictionary freeing name '%s'", nv->name);
 118         freez(nv->name);
 119     }
 120
 121     freez(nv);
 122 }
 123
 124 // ----------------------------------------------------------------------------
 125 // API - basic methods
 126
 127 DICTIONARY *dictionary_create(uint8_t flags) {
 128     debug(D_DICTIONARY, "Creating dictionary.");
 129
 130     DICTIONARY *dict = callocz(1, sizeof(DICTIONARY));
 131
 132     if(flags & DICTIONARY_FLAG_WITH_STATISTICS)
 133         dict->stats = callocz(1, sizeof(struct dictionary_stats));
 134
 135     if(!(flags & DICTIONARY_FLAG_SINGLE_THREADED)) {
 136         dict->rwlock = callocz(1, sizeof(pthread_rwlock_t));
 137         pthread_rwlock_init(dict->rwlock, NULL);
 138     }
 139
 140     avl_init(&dict->values_index, name_value_compare);
 141     dict->flags = flags;
 142
 143     return dict;
 144 }
 145
 146 void dictionary_destroy(DICTIONARY *dict) {
 147     debug(D_DICTIONARY, "Destroying dictionary.");
 148
 149     dictionary_write_lock(dict);
 150
 151     while(dict->values_index.root)
 152         dictionary_name_value_destroy_nolock(dict, (NAME_VALUE *)dict->values_index.root);
 153
 154     dictionary_unlock(dict);
 155
 156     if(dict->stats)
 157         freez(dict->stats);
 158
 159     if(dict->rwlock)
 160         freez(dict->rwlock);
 161
 162     freez(dict);
 163 }
 164
 165 // ----------------------------------------------------------------------------
 166
 167 void *dictionary_set(DICTIONARY *dict, const char *name, void *value, size_t value_len) {
 168     debug(D_DICTIONARY, "SET dictionary entry with name '%s'.", name);
 169
 170     uint32_t hash = simple_hash(name);
 171
 172     dictionary_write_lock(dict);
 173
 174     NAME_VALUE *nv = dictionary_name_value_index_find_nolock(dict, name, hash);
 175     if(unlikely(!nv)) {
 176         debug(D_DICTIONARY, "Dictionary entry with name '%s' not found. Creating a new one.", name);
 177
 178         nv = dictionary_name_value_create_nolock(dict, name, value, value_len, hash);
 179         if(unlikely(!nv))
 180             fatal("Cannot create name_value.");
 181     }
 182     else {
 183         debug(D_DICTIONARY, "Dictionary entry with name '%s' found. Changing its value.", name);
 184
 185         if(dict->flags & DICTIONARY_FLAG_VALUE_LINK_DONT_CLONE) {
 186             debug(D_REGISTRY, "Dictionary: linking value to '%s'", name);
 187             nv->value = value;
 188         }
 189         else {
 190             debug(D_REGISTRY, "Dictionary: cloning value to '%s'", name);
 191
 192             // copy the new value without breaking
 193             // any other thread accessing the same entry
 194             void *new = mallocz(value_len),
 195                     *old = nv->value;
 196
 197             memcpy(new, value, value_len);
 198             nv->value = new;
 199
 200             debug(D_REGISTRY, "Dictionary: freeing old value of '%s'", name);
 201             freez(old);
 202         }
 203     }
 204
 205     dictionary_unlock(dict);
 206
 207     return nv->value;
 208 }
 209
 210 void *dictionary_get(DICTIONARY *dict, const char *name) {
 211     debug(D_DICTIONARY, "GET dictionary entry with name '%s'.", name);
 212
 213     dictionary_read_lock(dict);
 214     NAME_VALUE *nv = dictionary_name_value_index_find_nolock(dict, name, 0);
 215     dictionary_unlock(dict);
 216
 217     if(unlikely(!nv)) {
 218         debug(D_DICTIONARY, "Not found dictionary entry with name '%s'.", name);
 219         return NULL;
 220     }
 221
 222     debug(D_DICTIONARY, "Found dictionary entry with name '%s'.", name);
 223     return nv->value;
 224 }
 225
 226 int dictionary_del(DICTIONARY *dict, const char *name) {
 227     int ret;
 228
 229     debug(D_DICTIONARY, "DEL dictionary entry with name '%s'.", name);
 230
 231     dictionary_write_lock(dict);
 232
 233     NAME_VALUE *nv = dictionary_name_value_index_find_nolock(dict, name, 0);
 234     if(unlikely(!nv)) {
 235         debug(D_DICTIONARY, "Not found dictionary entry with name '%s'.", name);
 236         ret = -1;
 237     }
 238     else {
 239         debug(D_DICTIONARY, "Found dictionary entry with name '%s'.", name);
 240         dictionary_name_value_destroy_nolock(dict, nv);
 241         ret = 0;
 242     }
 243
 244     dictionary_unlock(dict);
 245
 246     return ret;
 247 }
 248
 249
 250 // ----------------------------------------------------------------------------
 251 // API - walk through the dictionary
 252 // the dictionary is locked for reading while this happens
 253 // do not user other dictionary calls while walking the dictionary - deadlock!
 254
 255 static int dictionary_walker(avl *a, int (*callback)(void *entry, void *data), void *data) {
 256     int total = 0, ret = 0;
 257
 258     if(a->avl_link[0]) {
 259         ret = dictionary_walker(a->avl_link[0], callback, data);
 260         if(ret < 0) return ret;
 261         total += ret;
 262     }
 263
 264     ret = callback(((NAME_VALUE *)a)->value, data);
 265     if(ret < 0) return ret;
 266     total += ret;
 267
 268     if(a->avl_link[1]) {
 269         ret = dictionary_walker(a->avl_link[1], callback, data);
 270         if (ret < 0) return ret;
 271         total += ret;
 272     }
 273
 274     return total;
 275 }
 276
 277 int dictionary_get_all(DICTIONARY *dict, int (*callback)(void *entry, void *data), void *data) {
 278     int ret = 0;
 279
 280     dictionary_read_lock(dict);
 281
 282     if(likely(dict->values_index.root))
 283         ret = dictionary_walker(dict->values_index.root, callback, data);
 284
 285     dictionary_unlock(dict);
 286
 287     return ret;
 288 }