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