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 static inline NAME_VALUE *dictionary_name_value_index_find_nolock(DICTIONARY *dict, const char *name, uint32_t hash) {
  63     NAME_VALUE tmp;
  64     tmp.hash = (hash)?hash:simple_hash(name);
  65     tmp.name = (char *)name;
  66
  67     NETDATA_DICTIONARY_STATS_SEARCHES_PLUS1(dict);
  68     return (NAME_VALUE *)avl_search(&(dict->values_index), (avl *) &tmp);
  69 }
  70
  71 // ----------------------------------------------------------------------------
  72 // internal methods
  73
  74 static NAME_VALUE *dictionary_name_value_create_nolock(DICTIONARY *dict, const char *name, void *value, size_t value_len, uint32_t hash) {
  75     debug(D_DICTIONARY, "Creating name value entry for name '%s'.", name);
  76
  77     NAME_VALUE *nv = callocz(1, sizeof(NAME_VALUE));
  78
  79     if(dict->flags & DICTIONARY_FLAG_NAME_LINK_DONT_CLONE)
  80         nv->name = (char *)name;
  81     else {
  82         nv->name = strdupz(name);
  83     }
  84
  85     nv->hash = (hash)?hash:simple_hash(nv->name);
  86
  87     if(dict->flags & DICTIONARY_FLAG_VALUE_LINK_DONT_CLONE)
  88         nv->value = value;
  89     else {
  90         nv->value = mallocz(value_len);
  91         memcpy(nv->value, value, value_len);
  92     }
  93
  94     // index it
  95     NETDATA_DICTIONARY_STATS_INSERTS_PLUS1(dict);
  96     if(unlikely(avl_insert(&((dict)->values_index), (avl *)(nv)) != (avl *)nv))
  97         error("dictionary: INTERNAL ERROR: duplicate insertion to dictionary.");
  98
  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     NETDATA_DICTIONARY_STATS_DELETES_PLUS1(dict);
 108     if(unlikely(avl_remove(&(dict->values_index), (avl *)(nv)) != (avl *)nv))
 109         error("dictionary: INTERNAL ERROR: dictionary invalid removal of node.");
 110
 111     NETDATA_DICTIONARY_STATS_ENTRIES_MINUS1(dict);
 112
 113     if(!(dict->flags & DICTIONARY_FLAG_VALUE_LINK_DONT_CLONE)) {
 114         debug(D_REGISTRY, "Dictionary freeing value of '%s'", nv->name);
 115         freez(nv->value);
 116     }
 117
 118     if(!(dict->flags & DICTIONARY_FLAG_NAME_LINK_DONT_CLONE)) {
 119         debug(D_REGISTRY, "Dictionary freeing name '%s'", nv->name);
 120         freez(nv->name);
 121     }
 122
 123     freez(nv);
 124 }
 125
 126 // ----------------------------------------------------------------------------
 127 // API - basic methods
 128
 129 DICTIONARY *dictionary_create(uint8_t flags) {
 130     debug(D_DICTIONARY, "Creating dictionary.");
 131
 132     DICTIONARY *dict = callocz(1, sizeof(DICTIONARY));
 133
 134     if(flags & DICTIONARY_FLAG_WITH_STATISTICS)
 135         dict->stats = callocz(1, sizeof(struct dictionary_stats));
 136
 137     if(!(flags & DICTIONARY_FLAG_SINGLE_THREADED)) {
 138         dict->rwlock = callocz(1, sizeof(pthread_rwlock_t));
 139         pthread_rwlock_init(dict->rwlock, NULL);
 140     }
 141
 142     avl_init(&dict->values_index, name_value_compare);
 143     dict->flags = flags;
 144
 145     return dict;
 146 }
 147
 148 void dictionary_destroy(DICTIONARY *dict) {
 149     debug(D_DICTIONARY, "Destroying dictionary.");
 150
 151     dictionary_write_lock(dict);
 152
 153     while(dict->values_index.root)
 154         dictionary_name_value_destroy_nolock(dict, (NAME_VALUE *)dict->values_index.root);
 155
 156     dictionary_unlock(dict);
 157
 158     if(dict->stats)
 159         freez(dict->stats);
 160
 161     if(dict->rwlock)
 162         freez(dict->rwlock);
 163
 164     freez(dict);
 165 }
 166
 167 // ----------------------------------------------------------------------------
 168
 169 void *dictionary_set(DICTIONARY *dict, const char *name, void *value, size_t value_len) {
 170     debug(D_DICTIONARY, "SET dictionary entry with name '%s'.", name);
 171
 172     uint32_t hash = simple_hash(name);
 173
 174     dictionary_write_lock(dict);
 175
 176     NAME_VALUE *nv = dictionary_name_value_index_find_nolock(dict, name, hash);
 177     if(unlikely(!nv)) {
 178         debug(D_DICTIONARY, "Dictionary entry with name '%s' not found. Creating a new one.", name);
 179
 180         nv = dictionary_name_value_create_nolock(dict, name, value, value_len, hash);
 181         if(unlikely(!nv))
 182             fatal("Cannot create name_value.");
 183     }
 184     else {
 185         debug(D_DICTIONARY, "Dictionary entry with name '%s' found. Changing its value.", name);
 186
 187         if(dict->flags & DICTIONARY_FLAG_VALUE_LINK_DONT_CLONE) {
 188             debug(D_REGISTRY, "Dictionary: linking value to '%s'", name);
 189             nv->value = value;
 190         }
 191         else {
 192             debug(D_REGISTRY, "Dictionary: cloning value to '%s'", name);
 193
 194             // copy the new value without breaking
 195             // any other thread accessing the same entry
 196             void *new = mallocz(value_len),
 197                     *old = nv->value;
 198
 199             memcpy(new, value, value_len);
 200             nv->value = new;
 201
 202             debug(D_REGISTRY, "Dictionary: freeing old value of '%s'", name);
 203             freez(old);
 204         }
 205     }
 206
 207     dictionary_unlock(dict);
 208
 209     return nv->value;
 210 }
 211
 212 void *dictionary_get(DICTIONARY *dict, const char *name) {
 213     debug(D_DICTIONARY, "GET dictionary entry with name '%s'.", name);
 214
 215     dictionary_read_lock(dict);
 216     NAME_VALUE *nv = dictionary_name_value_index_find_nolock(dict, name, 0);
 217     dictionary_unlock(dict);
 218
 219     if(unlikely(!nv)) {
 220         debug(D_DICTIONARY, "Not found dictionary entry with name '%s'.", name);
 221         return NULL;
 222     }
 223
 224     debug(D_DICTIONARY, "Found dictionary entry with name '%s'.", name);
 225     return nv->value;
 226 }
 227
 228 int dictionary_del(DICTIONARY *dict, const char *name) {
 229     int ret;
 230
 231     debug(D_DICTIONARY, "DEL dictionary entry with name '%s'.", name);
 232
 233     dictionary_write_lock(dict);
 234
 235     NAME_VALUE *nv = dictionary_name_value_index_find_nolock(dict, name, 0);
 236     if(unlikely(!nv)) {
 237         debug(D_DICTIONARY, "Not found dictionary entry with name '%s'.", name);
 238         ret = -1;
 239     }
 240     else {
 241         debug(D_DICTIONARY, "Found dictionary entry with name '%s'.", name);
 242         dictionary_name_value_destroy_nolock(dict, nv);
 243         ret = 0;
 244     }
 245
 246     dictionary_unlock(dict);
 247
 248     return ret;
 249 }
 250
 251
 252 // ----------------------------------------------------------------------------
 253 // API - walk through the dictionary
 254 // the dictionary is locked for reading while this happens
 255 // do not user other dictionary calls while walking the dictionary - deadlock!
 256
 257 static int dictionary_walker(avl *a, int (*callback)(void *entry, void *data), void *data) {
 258     int total = 0, ret = 0;
 259
 260     if(a->avl_link[0]) {
 261         ret = dictionary_walker(a->avl_link[0], callback, data);
 262         if(ret < 0) return ret;
 263         total += ret;
 264     }
 265
 266     ret = callback(((NAME_VALUE *)a)->value, data);
 267     if(ret < 0) return ret;
 268     total += ret;
 269
 270     if(a->avl_link[1]) {
 271         ret = dictionary_walker(a->avl_link[1], callback, data);
 272         if (ret < 0) return ret;
 273         total += ret;
 274     }
 275
 276     return total;
 277 }
 278
 279 int dictionary_get_all(DICTIONARY *dict, int (*callback)(void *entry, void *data), void *data) {
 280     int ret = 0;
 281
 282     dictionary_read_lock(dict);
 283
 284     if(likely(dict->values_index.root))
 285         ret = dictionary_walker(dict->values_index.root, callback, data);
 286
 287     dictionary_unlock(dict);
 288
 289     return ret;
 290 }