src/object.c

   1 #include "redis.h"
   2 #include <math.h>
   3
   4 robj *createObject(int type, void *ptr) {
   5     robj *o = zmalloc(sizeof(*o));
   6     o->type = type;
   7     o->encoding = REDIS_ENCODING_RAW;
   8     o->ptr = ptr;
   9     o->refcount = 1;
  10
  11     /* Set the LRU to the current lruclock (minutes resolution).
  12      * We do this regardless of the fact VM is active as LRU is also
  13      * used for the maxmemory directive when Redis is used as cache.
  14      *
  15      * Note that this code may run in the context of an I/O thread
  16      * and accessing server.lruclock in theory is an error
  17      * (no locks). But in practice this is safe, and even if we read
  18      * garbage Redis will not fail. */
  19     o->lru = server.lruclock;
  20     /* The following is only needed if VM is active, but since the conditional
  21      * is probably more costly than initializing the field it's better to
  22      * have every field properly initialized anyway. */
  23     return o;
  24 }
  25
  26 robj *createStringObject(char *ptr, size_t len) {
  27     return createObject(REDIS_STRING,sdsnewlen(ptr,len));
  28 }
  29
  30 robj *createStringObjectFromLongLong(long long value) {
  31     robj *o;
  32     if (value >= 0 && value < REDIS_SHARED_INTEGERS) {
  33         incrRefCount(shared.integers[value]);
  34         o = shared.integers[value];
  35     } else {
  36         if (value >= LONG_MIN && value <= LONG_MAX) {
  37             o = createObject(REDIS_STRING, NULL);
  38             o->encoding = REDIS_ENCODING_INT;
  39             o->ptr = (void*)((long)value);
  40         } else {
  41             o = createObject(REDIS_STRING,sdsfromlonglong(value));
  42         }
  43     }
  44     return o;
  45 }
  46
  47 robj *dupStringObject(robj *o) {
  48     redisAssert(o->encoding == REDIS_ENCODING_RAW);
  49     return createStringObject(o->ptr,sdslen(o->ptr));
  50 }
  51
  52 robj *createListObject(void) {
  53     list *l = listCreate();
  54     robj *o = createObject(REDIS_LIST,l);
  55     listSetFreeMethod(l,decrRefCount);
  56     o->encoding = REDIS_ENCODING_LINKEDLIST;
  57     return o;
  58 }
  59
  60 robj *createZiplistObject(void) {
  61     unsigned char *zl = ziplistNew();
  62     robj *o = createObject(REDIS_LIST,zl);
  63     o->encoding = REDIS_ENCODING_ZIPLIST;
  64     return o;
  65 }
  66
  67 robj *createSetObject(void) {
  68     dict *d = dictCreate(&setDictType,NULL);
  69     robj *o = createObject(REDIS_SET,d);
  70     o->encoding = REDIS_ENCODING_HT;
  71     return o;
  72 }
  73
  74 robj *createIntsetObject(void) {
  75     intset *is = intsetNew();
  76     robj *o = createObject(REDIS_SET,is);
  77     o->encoding = REDIS_ENCODING_INTSET;
  78     return o;
  79 }
  80
  81 robj *createHashObject(void) {
  82     /* All the Hashes start as zipmaps. Will be automatically converted
  83      * into hash tables if there are enough elements or big elements
  84      * inside. */
  85     unsigned char *zm = zipmapNew();
  86     robj *o = createObject(REDIS_HASH,zm);
  87     o->encoding = REDIS_ENCODING_ZIPMAP;
  88     return o;
  89 }
  90
  91 robj *createZsetObject(void) {
  92     zset *zs = zmalloc(sizeof(*zs));
  93     robj *o;
  94
  95     zs->dict = dictCreate(&zsetDictType,NULL);
  96     zs->zsl = zslCreate();
  97     o = createObject(REDIS_ZSET,zs);
  98     o->encoding = REDIS_ENCODING_SKIPLIST;
  99     return o;
 100 }
 101
 102 robj *createZsetZiplistObject(void) {
 103     unsigned char *zl = ziplistNew();
 104     robj *o = createObject(REDIS_ZSET,zl);
 105     o->encoding = REDIS_ENCODING_ZIPLIST;
 106     return o;
 107 }
 108
 109 void freeStringObject(robj *o) {
 110     if (o->encoding == REDIS_ENCODING_RAW) {
 111         sdsfree(o->ptr);
 112     }
 113 }
 114
 115 void freeListObject(robj *o) {
 116     switch (o->encoding) {
 117     case REDIS_ENCODING_LINKEDLIST:
 118         listRelease((list*) o->ptr);
 119         break;
 120     case REDIS_ENCODING_ZIPLIST:
 121         zfree(o->ptr);
 122         break;
 123     default:
 124         redisPanic("Unknown list encoding type");
 125     }
 126 }
 127
 128 void freeSetObject(robj *o) {
 129     switch (o->encoding) {
 130     case REDIS_ENCODING_HT:
 131         dictRelease((dict*) o->ptr);
 132         break;
 133     case REDIS_ENCODING_INTSET:
 134         zfree(o->ptr);
 135         break;
 136     default:
 137         redisPanic("Unknown set encoding type");
 138     }
 139 }
 140
 141 void freeZsetObject(robj *o) {
 142     zset *zs;
 143     switch (o->encoding) {
 144     case REDIS_ENCODING_SKIPLIST:
 145         zs = o->ptr;
 146         dictRelease(zs->dict);
 147         zslFree(zs->zsl);
 148         zfree(zs);
 149         break;
 150     case REDIS_ENCODING_ZIPLIST:
 151         zfree(o->ptr);
 152         break;
 153     default:
 154         redisPanic("Unknown sorted set encoding");
 155     }
 156 }
 157
 158 void freeHashObject(robj *o) {
 159     switch (o->encoding) {
 160     case REDIS_ENCODING_HT:
 161         dictRelease((dict*) o->ptr);
 162         break;
 163     case REDIS_ENCODING_ZIPMAP:
 164         zfree(o->ptr);
 165         break;
 166     default:
 167         redisPanic("Unknown hash encoding type");
 168         break;
 169     }
 170 }
 171
 172 void incrRefCount(robj *o) {
 173     o->refcount++;
 174 }
 175
 176 void decrRefCount(void *obj) {
 177     robj *o = obj;
 178
 179     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 180     if (o->refcount == 1) {
 181         switch(o->type) {
 182         case REDIS_STRING: freeStringObject(o); break;
 183         case REDIS_LIST: freeListObject(o); break;
 184         case REDIS_SET: freeSetObject(o); break;
 185         case REDIS_ZSET: freeZsetObject(o); break;
 186         case REDIS_HASH: freeHashObject(o); break;
 187         default: redisPanic("Unknown object type"); break;
 188         }
 189         zfree(o);
 190     } else {
 191         o->refcount--;
 192     }
 193 }
 194
 195 int checkType(redisClient *c, robj *o, int type) {
 196     if (o->type != type) {
 197         addReply(c,shared.wrongtypeerr);
 198         return 1;
 199     }
 200     return 0;
 201 }
 202
 203 int isObjectRepresentableAsLongLong(robj *o, long long *llval) {
 204     redisAssert(o->type == REDIS_STRING);
 205     if (o->encoding == REDIS_ENCODING_INT) {
 206         if (llval) *llval = (long) o->ptr;
 207         return REDIS_OK;
 208     } else {
 209         return string2ll(o->ptr,sdslen(o->ptr),llval) ? REDIS_OK : REDIS_ERR;
 210     }
 211 }
 212
 213 /* Try to encode a string object in order to save space */
 214 robj *tryObjectEncoding(robj *o) {
 215     long value;
 216     sds s = o->ptr;
 217
 218     if (o->encoding != REDIS_ENCODING_RAW)
 219         return o; /* Already encoded */
 220
 221     /* It's not safe to encode shared objects: shared objects can be shared
 222      * everywhere in the "object space" of Redis. Encoded objects can only
 223      * appear as "values" (and not, for instance, as keys) */
 224      if (o->refcount > 1) return o;
 225
 226     /* Currently we try to encode only strings */
 227     redisAssert(o->type == REDIS_STRING);
 228
 229     /* Check if we can represent this string as a long integer */
 230     if (!string2l(s,sdslen(s),&value)) return o;
 231
 232     /* Ok, this object can be encoded...
 233      *
 234      * Can I use a shared object? Only if the object is inside a given
 235      * range and if the back end in use is in-memory. For disk store every
 236      * object in memory used as value should be independent.
 237      *
 238      * Note that we also avoid using shared integers when maxmemory is used
 239      * because every object needs to have a private LRU field for the LRU
 240      * algorithm to work well. */
 241     if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS) {
 242         decrRefCount(o);
 243         incrRefCount(shared.integers[value]);
 244         return shared.integers[value];
 245     } else {
 246         o->encoding = REDIS_ENCODING_INT;
 247         sdsfree(o->ptr);
 248         o->ptr = (void*) value;
 249         return o;
 250     }
 251 }
 252
 253 /* Get a decoded version of an encoded object (returned as a new object).
 254  * If the object is already raw-encoded just increment the ref count. */
 255 robj *getDecodedObject(robj *o) {
 256     robj *dec;
 257
 258     if (o->encoding == REDIS_ENCODING_RAW) {
 259         incrRefCount(o);
 260         return o;
 261     }
 262     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 263         char buf[32];
 264
 265         ll2string(buf,32,(long)o->ptr);
 266         dec = createStringObject(buf,strlen(buf));
 267         return dec;
 268     } else {
 269         redisPanic("Unknown encoding type");
 270     }
 271 }
 272
 273 /* Compare two string objects via strcmp() or alike.
 274  * Note that the objects may be integer-encoded. In such a case we
 275  * use ll2string() to get a string representation of the numbers on the stack
 276  * and compare the strings, it's much faster than calling getDecodedObject().
 277  *
 278  * Important note: if objects are not integer encoded, but binary-safe strings,
 279  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 280  * binary safe. */
 281 int compareStringObjects(robj *a, robj *b) {
 282     redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
 283     char bufa[128], bufb[128], *astr, *bstr;
 284     int bothsds = 1;
 285
 286     if (a == b) return 0;
 287     if (a->encoding != REDIS_ENCODING_RAW) {
 288         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 289         astr = bufa;
 290         bothsds = 0;
 291     } else {
 292         astr = a->ptr;
 293     }
 294     if (b->encoding != REDIS_ENCODING_RAW) {
 295         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 296         bstr = bufb;
 297         bothsds = 0;
 298     } else {
 299         bstr = b->ptr;
 300     }
 301     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 302 }
 303
 304 /* Equal string objects return 1 if the two objects are the same from the
 305  * point of view of a string comparison, otherwise 0 is returned. Note that
 306  * this function is faster then checking for (compareStringObject(a,b) == 0)
 307  * because it can perform some more optimization. */
 308 int equalStringObjects(robj *a, robj *b) {
 309     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 310         return a->ptr == b->ptr;
 311     } else {
 312         return compareStringObjects(a,b) == 0;
 313     }
 314 }
 315
 316 size_t stringObjectLen(robj *o) {
 317     redisAssert(o->type == REDIS_STRING);
 318     if (o->encoding == REDIS_ENCODING_RAW) {
 319         return sdslen(o->ptr);
 320     } else {
 321         char buf[32];
 322
 323         return ll2string(buf,32,(long)o->ptr);
 324     }
 325 }
 326
 327 int getDoubleFromObject(robj *o, double *target) {
 328     double value;
 329     char *eptr;
 330
 331     if (o == NULL) {
 332         value = 0;
 333     } else {
 334         redisAssert(o->type == REDIS_STRING);
 335         if (o->encoding == REDIS_ENCODING_RAW) {
 336             value = strtod(o->ptr, &eptr);
 337             if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
 338         } else if (o->encoding == REDIS_ENCODING_INT) {
 339             value = (long)o->ptr;
 340         } else {
 341             redisPanic("Unknown string encoding");
 342         }
 343     }
 344
 345     *target = value;
 346     return REDIS_OK;
 347 }
 348
 349 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 350     double value;
 351     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 352         if (msg != NULL) {
 353             addReplyError(c,(char*)msg);
 354         } else {
 355             addReplyError(c,"value is not a double");
 356         }
 357         return REDIS_ERR;
 358     }
 359
 360     *target = value;
 361     return REDIS_OK;
 362 }
 363
 364 int getLongLongFromObject(robj *o, long long *target) {
 365     long long value;
 366     char *eptr;
 367
 368     if (o == NULL) {
 369         value = 0;
 370     } else {
 371         redisAssert(o->type == REDIS_STRING);
 372         if (o->encoding == REDIS_ENCODING_RAW) {
 373             value = strtoll(o->ptr, &eptr, 10);
 374             if (eptr[0] != '\0') return REDIS_ERR;
 375             if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
 376                 return REDIS_ERR;
 377         } else if (o->encoding == REDIS_ENCODING_INT) {
 378             value = (long)o->ptr;
 379         } else {
 380             redisPanic("Unknown string encoding");
 381         }
 382     }
 383
 384     if (target) *target = value;
 385     return REDIS_OK;
 386 }
 387
 388 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 389     long long value;
 390     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 391         if (msg != NULL) {
 392             addReplyError(c,(char*)msg);
 393         } else {
 394             addReplyError(c,"value is not an integer or out of range");
 395         }
 396         return REDIS_ERR;
 397     }
 398
 399     *target = value;
 400     return REDIS_OK;
 401 }
 402
 403 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 404     long long value;
 405
 406     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 407     if (value < LONG_MIN || value > LONG_MAX) {
 408         if (msg != NULL) {
 409             addReplyError(c,(char*)msg);
 410         } else {
 411             addReplyError(c,"value is out of range");
 412         }
 413         return REDIS_ERR;
 414     }
 415
 416     *target = value;
 417     return REDIS_OK;
 418 }
 419
 420 char *strEncoding(int encoding) {
 421     switch(encoding) {
 422     case REDIS_ENCODING_RAW: return "raw";
 423     case REDIS_ENCODING_INT: return "int";
 424     case REDIS_ENCODING_HT: return "hashtable";
 425     case REDIS_ENCODING_ZIPMAP: return "zipmap";
 426     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 427     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 428     case REDIS_ENCODING_INTSET: return "intset";
 429     case REDIS_ENCODING_SKIPLIST: return "skiplist";
 430     default: return "unknown";
 431     }
 432 }
 433
 434 /* Given an object returns the min number of seconds the object was never
 435  * requested, using an approximated LRU algorithm. */
 436 unsigned long estimateObjectIdleTime(robj *o) {
 437     if (server.lruclock >= o->lru) {
 438         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 439     } else {
 440         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 441                     REDIS_LRU_CLOCK_RESOLUTION;
 442     }
 443 }
 444
 445 /* This is an helper function for the DEBUG command. We need to lookup keys
 446  * without any modification of LRU or other parameters. */
 447 robj *objectCommandLookup(redisClient *c, robj *key) {
 448     dictEntry *de;
 449
 450     if ((de = dictFind(c->db->dict,key->ptr)) == NULL) return NULL;
 451     return (robj*) dictGetEntryVal(de);
 452 }
 453
 454 robj *objectCommandLookupOrReply(redisClient *c, robj *key, robj *reply) {
 455     robj *o = objectCommandLookup(c,key);
 456
 457     if (!o) addReply(c, reply);
 458     return o;
 459 }
 460
 461 /* Object command allows to inspect the internals of an Redis Object.
 462  * Usage: OBJECT <verb> ... arguments ... */
 463 void objectCommand(redisClient *c) {
 464     robj *o;
 465
 466     if (!strcasecmp(c->argv[1]->ptr,"refcount") && c->argc == 3) {
 467         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 468                 == NULL) return;
 469         addReplyLongLong(c,o->refcount);
 470     } else if (!strcasecmp(c->argv[1]->ptr,"encoding") && c->argc == 3) {
 471         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 472                 == NULL) return;
 473         addReplyBulkCString(c,strEncoding(o->encoding));
 474     } else if (!strcasecmp(c->argv[1]->ptr,"idletime") && c->argc == 3) {
 475         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 476                 == NULL) return;
 477         addReplyLongLong(c,estimateObjectIdleTime(o));
 478     } else {
 479         addReplyError(c,"Syntax error. Try OBJECT (refcount|encoding|idletime)");
 480     }
 481 }
 482