src/object.c

   1 #include "redis.h"
   2 #include <pthread.h>
   3 #include <math.h>
   4
   5 robj *createObject(int type, void *ptr) {
   6     robj *o = zmalloc(sizeof(*o));
   7     o->type = type;
   8     o->encoding = REDIS_ENCODING_RAW;
   9     o->ptr = ptr;
  10     o->refcount = 1;
  11
  12     /* Set the LRU to the current lruclock (minutes resolution).
  13      * We do this regardless of the fact VM is active as LRU is also
  14      * used for the maxmemory directive when Redis is used as cache.
  15      *
  16      * Note that this code may run in the context of an I/O thread
  17      * and accessing server.lruclock in theory is an error
  18      * (no locks). But in practice this is safe, and even if we read
  19      * garbage Redis will not fail. */
  20     o->lru = server.lruclock;
  21     /* The following is only needed if VM is active, but since the conditional
  22      * is probably more costly than initializing the field it's better to
  23      * have every field properly initialized anyway. */
  24     return o;
  25 }
  26
  27 robj *createStringObject(char *ptr, size_t len) {
  28     return createObject(REDIS_STRING,sdsnewlen(ptr,len));
  29 }
  30
  31 robj *createStringObjectFromLongLong(long long value) {
  32     robj *o;
  33     if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
  34         !server.ds_enabled &&
  35         pthread_equal(pthread_self(),server.mainthread)) {
  36         incrRefCount(shared.integers[value]);
  37         o = shared.integers[value];
  38     } else {
  39         if (value >= LONG_MIN && value <= LONG_MAX) {
  40             o = createObject(REDIS_STRING, NULL);
  41             o->encoding = REDIS_ENCODING_INT;
  42             o->ptr = (void*)((long)value);
  43         } else {
  44             o = createObject(REDIS_STRING,sdsfromlonglong(value));
  45         }
  46     }
  47     return o;
  48 }
  49
  50 robj *dupStringObject(robj *o) {
  51     redisAssert(o->encoding == REDIS_ENCODING_RAW);
  52     return createStringObject(o->ptr,sdslen(o->ptr));
  53 }
  54
  55 robj *createListObject(void) {
  56     list *l = listCreate();
  57     robj *o = createObject(REDIS_LIST,l);
  58     listSetFreeMethod(l,decrRefCount);
  59     o->encoding = REDIS_ENCODING_LINKEDLIST;
  60     return o;
  61 }
  62
  63 robj *createZiplistObject(void) {
  64     unsigned char *zl = ziplistNew();
  65     robj *o = createObject(REDIS_LIST,zl);
  66     o->encoding = REDIS_ENCODING_ZIPLIST;
  67     return o;
  68 }
  69
  70 robj *createSetObject(void) {
  71     dict *d = dictCreate(&setDictType,NULL);
  72     robj *o = createObject(REDIS_SET,d);
  73     o->encoding = REDIS_ENCODING_HT;
  74     return o;
  75 }
  76
  77 robj *createIntsetObject(void) {
  78     intset *is = intsetNew();
  79     robj *o = createObject(REDIS_SET,is);
  80     o->encoding = REDIS_ENCODING_INTSET;
  81     return o;
  82 }
  83
  84 robj *createHashObject(void) {
  85     /* All the Hashes start as zipmaps. Will be automatically converted
  86      * into hash tables if there are enough elements or big elements
  87      * inside. */
  88     unsigned char *zm = zipmapNew();
  89     robj *o = createObject(REDIS_HASH,zm);
  90     o->encoding = REDIS_ENCODING_ZIPMAP;
  91     return o;
  92 }
  93
  94 robj *createZsetObject(void) {
  95     zset *zs = zmalloc(sizeof(*zs));
  96     zs->dict = dictCreate(&zsetDictType,NULL);
  97     zs->zsl = zslCreate();
  98     return createObject(REDIS_ZSET,zs);
  99 }
 100
 101 robj *createZsetZiplistObject(void) {
 102     unsigned char *zl = ziplistNew();
 103     robj *o = createObject(REDIS_ZSET,zl);
 104     o->encoding = REDIS_ENCODING_ZIPLIST;
 105     return o;
 106 }
 107
 108 void freeStringObject(robj *o) {
 109     if (o->encoding == REDIS_ENCODING_RAW) {
 110         sdsfree(o->ptr);
 111     }
 112 }
 113
 114 void freeListObject(robj *o) {
 115     switch (o->encoding) {
 116     case REDIS_ENCODING_LINKEDLIST:
 117         listRelease((list*) o->ptr);
 118         break;
 119     case REDIS_ENCODING_ZIPLIST:
 120         zfree(o->ptr);
 121         break;
 122     default:
 123         redisPanic("Unknown list encoding type");
 124     }
 125 }
 126
 127 void freeSetObject(robj *o) {
 128     switch (o->encoding) {
 129     case REDIS_ENCODING_HT:
 130         dictRelease((dict*) o->ptr);
 131         break;
 132     case REDIS_ENCODING_INTSET:
 133         zfree(o->ptr);
 134         break;
 135     default:
 136         redisPanic("Unknown set encoding type");
 137     }
 138 }
 139
 140 void freeZsetObject(robj *o) {
 141     zset *zs;
 142     switch (o->encoding) {
 143     case REDIS_ENCODING_RAW:
 144         zs = o->ptr;
 145         dictRelease(zs->dict);
 146         zslFree(zs->zsl);
 147         zfree(zs);
 148         break;
 149     case REDIS_ENCODING_ZIPLIST:
 150         zfree(o->ptr);
 151         break;
 152     default:
 153         redisPanic("Unknown sorted set encoding");
 154     }
 155 }
 156
 157 void freeHashObject(robj *o) {
 158     switch (o->encoding) {
 159     case REDIS_ENCODING_HT:
 160         dictRelease((dict*) o->ptr);
 161         break;
 162     case REDIS_ENCODING_ZIPMAP:
 163         zfree(o->ptr);
 164         break;
 165     default:
 166         redisPanic("Unknown hash encoding type");
 167         break;
 168     }
 169 }
 170
 171 void incrRefCount(robj *o) {
 172     o->refcount++;
 173 }
 174
 175 void decrRefCount(void *obj) {
 176     robj *o = obj;
 177
 178     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 179     if (--(o->refcount) == 0) {
 180         switch(o->type) {
 181         case REDIS_STRING: freeStringObject(o); break;
 182         case REDIS_LIST: freeListObject(o); break;
 183         case REDIS_SET: freeSetObject(o); break;
 184         case REDIS_ZSET: freeZsetObject(o); break;
 185         case REDIS_HASH: freeHashObject(o); break;
 186         default: redisPanic("Unknown object type"); break;
 187         }
 188         o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
 189         zfree(o);
 190     }
 191 }
 192
 193 int checkType(redisClient *c, robj *o, int type) {
 194     if (o->type != type) {
 195         addReply(c,shared.wrongtypeerr);
 196         return 1;
 197     }
 198     return 0;
 199 }
 200
 201 /* Try to encode a string object in order to save space */
 202 robj *tryObjectEncoding(robj *o) {
 203     long value;
 204     sds s = o->ptr;
 205
 206     if (o->encoding != REDIS_ENCODING_RAW)
 207         return o; /* Already encoded */
 208
 209     /* It's not safe to encode shared objects: shared objects can be shared
 210      * everywhere in the "object space" of Redis. Encoded objects can only
 211      * appear as "values" (and not, for instance, as keys) */
 212      if (o->refcount > 1) return o;
 213
 214     /* Currently we try to encode only strings */
 215     redisAssert(o->type == REDIS_STRING);
 216
 217     /* Check if we can represent this string as a long integer */
 218     if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
 219
 220     /* Ok, this object can be encoded...
 221      *
 222      * Can I use a shared object? Only if the object is inside a given
 223      * range and if the back end in use is in-memory. For disk store every
 224      * object in memory used as value should be independent.
 225      *
 226      * Note that we also avoid using shared integers when maxmemory is used
 227      * because every object needs to have a private LRU field for the LRU
 228      * algorithm to work well. */
 229     if (!server.ds_enabled &&
 230         server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
 231         pthread_equal(pthread_self(),server.mainthread))
 232     {
 233         decrRefCount(o);
 234         incrRefCount(shared.integers[value]);
 235         return shared.integers[value];
 236     } else {
 237         o->encoding = REDIS_ENCODING_INT;
 238         sdsfree(o->ptr);
 239         o->ptr = (void*) value;
 240         return o;
 241     }
 242 }
 243
 244 /* Get a decoded version of an encoded object (returned as a new object).
 245  * If the object is already raw-encoded just increment the ref count. */
 246 robj *getDecodedObject(robj *o) {
 247     robj *dec;
 248
 249     if (o->encoding == REDIS_ENCODING_RAW) {
 250         incrRefCount(o);
 251         return o;
 252     }
 253     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 254         char buf[32];
 255
 256         ll2string(buf,32,(long)o->ptr);
 257         dec = createStringObject(buf,strlen(buf));
 258         return dec;
 259     } else {
 260         redisPanic("Unknown encoding type");
 261     }
 262 }
 263
 264 /* Compare two string objects via strcmp() or alike.
 265  * Note that the objects may be integer-encoded. In such a case we
 266  * use ll2string() to get a string representation of the numbers on the stack
 267  * and compare the strings, it's much faster than calling getDecodedObject().
 268  *
 269  * Important note: if objects are not integer encoded, but binary-safe strings,
 270  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 271  * binary safe. */
 272 int compareStringObjects(robj *a, robj *b) {
 273     redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
 274     char bufa[128], bufb[128], *astr, *bstr;
 275     int bothsds = 1;
 276
 277     if (a == b) return 0;
 278     if (a->encoding != REDIS_ENCODING_RAW) {
 279         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 280         astr = bufa;
 281         bothsds = 0;
 282     } else {
 283         astr = a->ptr;
 284     }
 285     if (b->encoding != REDIS_ENCODING_RAW) {
 286         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 287         bstr = bufb;
 288         bothsds = 0;
 289     } else {
 290         bstr = b->ptr;
 291     }
 292     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 293 }
 294
 295 /* Equal string objects return 1 if the two objects are the same from the
 296  * point of view of a string comparison, otherwise 0 is returned. Note that
 297  * this function is faster then checking for (compareStringObject(a,b) == 0)
 298  * because it can perform some more optimization. */
 299 int equalStringObjects(robj *a, robj *b) {
 300     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 301         return a->ptr == b->ptr;
 302     } else {
 303         return compareStringObjects(a,b) == 0;
 304     }
 305 }
 306
 307 size_t stringObjectLen(robj *o) {
 308     redisAssert(o->type == REDIS_STRING);
 309     if (o->encoding == REDIS_ENCODING_RAW) {
 310         return sdslen(o->ptr);
 311     } else {
 312         char buf[32];
 313
 314         return ll2string(buf,32,(long)o->ptr);
 315     }
 316 }
 317
 318 int getDoubleFromObject(robj *o, double *target) {
 319     double value;
 320     char *eptr;
 321
 322     if (o == NULL) {
 323         value = 0;
 324     } else {
 325         redisAssert(o->type == REDIS_STRING);
 326         if (o->encoding == REDIS_ENCODING_RAW) {
 327             value = strtod(o->ptr, &eptr);
 328             if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
 329         } else if (o->encoding == REDIS_ENCODING_INT) {
 330             value = (long)o->ptr;
 331         } else {
 332             redisPanic("Unknown string encoding");
 333         }
 334     }
 335
 336     *target = value;
 337     return REDIS_OK;
 338 }
 339
 340 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 341     double value;
 342     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 343         if (msg != NULL) {
 344             addReplyError(c,(char*)msg);
 345         } else {
 346             addReplyError(c,"value is not a double");
 347         }
 348         return REDIS_ERR;
 349     }
 350
 351     *target = value;
 352     return REDIS_OK;
 353 }
 354
 355 int getLongLongFromObject(robj *o, long long *target) {
 356     long long value;
 357     char *eptr;
 358
 359     if (o == NULL) {
 360         value = 0;
 361     } else {
 362         redisAssert(o->type == REDIS_STRING);
 363         if (o->encoding == REDIS_ENCODING_RAW) {
 364             value = strtoll(o->ptr, &eptr, 10);
 365             if (eptr[0] != '\0') return REDIS_ERR;
 366             if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
 367                 return REDIS_ERR;
 368         } else if (o->encoding == REDIS_ENCODING_INT) {
 369             value = (long)o->ptr;
 370         } else {
 371             redisPanic("Unknown string encoding");
 372         }
 373     }
 374
 375     if (target) *target = value;
 376     return REDIS_OK;
 377 }
 378
 379 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 380     long long value;
 381     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 382         if (msg != NULL) {
 383             addReplyError(c,(char*)msg);
 384         } else {
 385             addReplyError(c,"value is not an integer or out of range");
 386         }
 387         return REDIS_ERR;
 388     }
 389
 390     *target = value;
 391     return REDIS_OK;
 392 }
 393
 394 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 395     long long value;
 396
 397     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 398     if (value < LONG_MIN || value > LONG_MAX) {
 399         if (msg != NULL) {
 400             addReplyError(c,(char*)msg);
 401         } else {
 402             addReplyError(c,"value is out of range");
 403         }
 404         return REDIS_ERR;
 405     }
 406
 407     *target = value;
 408     return REDIS_OK;
 409 }
 410
 411 char *strEncoding(int encoding) {
 412     switch(encoding) {
 413     case REDIS_ENCODING_RAW: return "raw";
 414     case REDIS_ENCODING_INT: return "int";
 415     case REDIS_ENCODING_HT: return "hashtable";
 416     case REDIS_ENCODING_ZIPMAP: return "zipmap";
 417     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 418     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 419     case REDIS_ENCODING_INTSET: return "intset";
 420     default: return "unknown";
 421     }
 422 }
 423
 424 /* Given an object returns the min number of seconds the object was never
 425  * requested, using an approximated LRU algorithm. */
 426 unsigned long estimateObjectIdleTime(robj *o) {
 427     if (server.lruclock >= o->lru) {
 428         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 429     } else {
 430         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 431                     REDIS_LRU_CLOCK_RESOLUTION;
 432     }
 433 }