src/object.c

   1 #include "redis.h"
   2 #include <math.h>
   3 #include <ctype.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         incrRefCount(shared.integers[value]);
  35         o = shared.integers[value];
  36     } else {
  37         if (value >= LONG_MIN && value <= LONG_MAX) {
  38             o = createObject(REDIS_STRING, NULL);
  39             o->encoding = REDIS_ENCODING_INT;
  40             o->ptr = (void*)((long)value);
  41         } else {
  42             o = createObject(REDIS_STRING,sdsfromlonglong(value));
  43         }
  44     }
  45     return o;
  46 }
  47
  48 /* Note: this function is defined into object.c since here it is where it
  49  * belongs but it is actually designed to be used just for INCRBYFLOAT */
  50 robj *createStringObjectFromLongDouble(long double value) {
  51     char buf[256];
  52     int len;
  53
  54     /* We use 17 digits precision since with 128 bit floats that precision
  55      * after rouding is able to represent most small decimal numbers in a way
  56      * that is "non surprising" for the user (that is, most small decimal
  57      * numbers will be represented in a way that when converted back into
  58      * a string are exactly the same as what the user typed.) */
  59     len = snprintf(buf,sizeof(buf),"%.17Lg", value);
  60     return createStringObject(buf,len);
  61 }
  62
  63 robj *dupStringObject(robj *o) {
  64     redisAssertWithInfo(NULL,o,o->encoding == REDIS_ENCODING_RAW);
  65     return createStringObject(o->ptr,sdslen(o->ptr));
  66 }
  67
  68 robj *createListObject(void) {
  69     list *l = listCreate();
  70     robj *o = createObject(REDIS_LIST,l);
  71     listSetFreeMethod(l,decrRefCount);
  72     o->encoding = REDIS_ENCODING_LINKEDLIST;
  73     return o;
  74 }
  75
  76 robj *createZiplistObject(void) {
  77     unsigned char *zl = ziplistNew();
  78     robj *o = createObject(REDIS_LIST,zl);
  79     o->encoding = REDIS_ENCODING_ZIPLIST;
  80     return o;
  81 }
  82
  83 robj *createSetObject(void) {
  84     dict *d = dictCreate(&setDictType,NULL);
  85     robj *o = createObject(REDIS_SET,d);
  86     o->encoding = REDIS_ENCODING_HT;
  87     return o;
  88 }
  89
  90 robj *createIntsetObject(void) {
  91     intset *is = intsetNew();
  92     robj *o = createObject(REDIS_SET,is);
  93     o->encoding = REDIS_ENCODING_INTSET;
  94     return o;
  95 }
  96
  97 robj *createHashObject(void) {
  98     unsigned char *zl = ziplistNew();
  99     robj *o = createObject(REDIS_HASH, zl);
 100     o->encoding = REDIS_ENCODING_ZIPLIST;
 101     return o;
 102 }
 103
 104 robj *createZsetObject(void) {
 105     zset *zs = zmalloc(sizeof(*zs));
 106     robj *o;
 107
 108     zs->dict = dictCreate(&zsetDictType,NULL);
 109     zs->zsl = zslCreate();
 110     o = createObject(REDIS_ZSET,zs);
 111     o->encoding = REDIS_ENCODING_SKIPLIST;
 112     return o;
 113 }
 114
 115 robj *createZsetZiplistObject(void) {
 116     unsigned char *zl = ziplistNew();
 117     robj *o = createObject(REDIS_ZSET,zl);
 118     o->encoding = REDIS_ENCODING_ZIPLIST;
 119     return o;
 120 }
 121
 122 void freeStringObject(robj *o) {
 123     if (o->encoding == REDIS_ENCODING_RAW) {
 124         sdsfree(o->ptr);
 125     }
 126 }
 127
 128 void freeListObject(robj *o) {
 129     switch (o->encoding) {
 130     case REDIS_ENCODING_LINKEDLIST:
 131         listRelease((list*) o->ptr);
 132         break;
 133     case REDIS_ENCODING_ZIPLIST:
 134         zfree(o->ptr);
 135         break;
 136     default:
 137         redisPanic("Unknown list encoding type");
 138     }
 139 }
 140
 141 void freeSetObject(robj *o) {
 142     switch (o->encoding) {
 143     case REDIS_ENCODING_HT:
 144         dictRelease((dict*) o->ptr);
 145         break;
 146     case REDIS_ENCODING_INTSET:
 147         zfree(o->ptr);
 148         break;
 149     default:
 150         redisPanic("Unknown set encoding type");
 151     }
 152 }
 153
 154 void freeZsetObject(robj *o) {
 155     zset *zs;
 156     switch (o->encoding) {
 157     case REDIS_ENCODING_SKIPLIST:
 158         zs = o->ptr;
 159         dictRelease(zs->dict);
 160         zslFree(zs->zsl);
 161         zfree(zs);
 162         break;
 163     case REDIS_ENCODING_ZIPLIST:
 164         zfree(o->ptr);
 165         break;
 166     default:
 167         redisPanic("Unknown sorted set encoding");
 168     }
 169 }
 170
 171 void freeHashObject(robj *o) {
 172     switch (o->encoding) {
 173     case REDIS_ENCODING_HT:
 174         dictRelease((dict*) o->ptr);
 175         break;
 176     case REDIS_ENCODING_ZIPLIST:
 177         zfree(o->ptr);
 178         break;
 179     default:
 180         redisPanic("Unknown hash encoding type");
 181         break;
 182     }
 183 }
 184
 185 void incrRefCount(robj *o) {
 186     o->refcount++;
 187 }
 188
 189 void decrRefCount(void *obj) {
 190     robj *o = obj;
 191
 192     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 193     if (o->refcount == 1) {
 194         switch(o->type) {
 195         case REDIS_STRING: freeStringObject(o); break;
 196         case REDIS_LIST: freeListObject(o); break;
 197         case REDIS_SET: freeSetObject(o); break;
 198         case REDIS_ZSET: freeZsetObject(o); break;
 199         case REDIS_HASH: freeHashObject(o); break;
 200         default: redisPanic("Unknown object type"); break;
 201         }
 202         zfree(o);
 203     } else {
 204         o->refcount--;
 205     }
 206 }
 207
 208 /* This function set the ref count to zero without freeing the object.
 209  * It is useful in order to pass a new object to functions incrementing
 210  * the ref count of the received object. Example:
 211  *
 212  *    functionThatWillIncrementRefCount(resetRefCount(CreateObject(...)));
 213  *
 214  * Otherwise you need to resort to the less elegant pattern:
 215  *
 216  *    *obj = createObject(...);
 217  *    functionThatWillIncrementRefCount(obj);
 218  *    decrRefCount(obj);
 219  */
 220 robj *resetRefCount(robj *obj) {
 221     obj->refcount = 0;
 222     return obj;
 223 }
 224
 225 int checkType(redisClient *c, robj *o, int type) {
 226     if (o->type != type) {
 227         addReply(c,shared.wrongtypeerr);
 228         return 1;
 229     }
 230     return 0;
 231 }
 232
 233 int isObjectRepresentableAsLongLong(robj *o, long long *llval) {
 234     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 235     if (o->encoding == REDIS_ENCODING_INT) {
 236         if (llval) *llval = (long) o->ptr;
 237         return REDIS_OK;
 238     } else {
 239         return string2ll(o->ptr,sdslen(o->ptr),llval) ? REDIS_OK : REDIS_ERR;
 240     }
 241 }
 242
 243 /* Try to encode a string object in order to save space */
 244 robj *tryObjectEncoding(robj *o) {
 245     long value;
 246     sds s = o->ptr;
 247
 248     if (o->encoding != REDIS_ENCODING_RAW)
 249         return o; /* Already encoded */
 250
 251     /* It's not safe to encode shared objects: shared objects can be shared
 252      * everywhere in the "object space" of Redis. Encoded objects can only
 253      * appear as "values" (and not, for instance, as keys) */
 254      if (o->refcount > 1) return o;
 255
 256     /* Currently we try to encode only strings */
 257     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 258
 259     /* Check if we can represent this string as a long integer */
 260     if (!string2l(s,sdslen(s),&value)) return o;
 261
 262     /* Ok, this object can be encoded...
 263      *
 264      * Can I use a shared object? Only if the object is inside a given
 265      * range and if the back end in use is in-memory. For disk store every
 266      * object in memory used as value should be independent.
 267      *
 268      * Note that we also avoid using shared integers when maxmemory is used
 269      * because every object needs to have a private LRU field for the LRU
 270      * algorithm to work well. */
 271     if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS) {
 272         decrRefCount(o);
 273         incrRefCount(shared.integers[value]);
 274         return shared.integers[value];
 275     } else {
 276         o->encoding = REDIS_ENCODING_INT;
 277         sdsfree(o->ptr);
 278         o->ptr = (void*) value;
 279         return o;
 280     }
 281 }
 282
 283 /* Get a decoded version of an encoded object (returned as a new object).
 284  * If the object is already raw-encoded just increment the ref count. */
 285 robj *getDecodedObject(robj *o) {
 286     robj *dec;
 287
 288     if (o->encoding == REDIS_ENCODING_RAW) {
 289         incrRefCount(o);
 290         return o;
 291     }
 292     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 293         char buf[32];
 294
 295         ll2string(buf,32,(long)o->ptr);
 296         dec = createStringObject(buf,strlen(buf));
 297         return dec;
 298     } else {
 299         redisPanic("Unknown encoding type");
 300     }
 301 }
 302
 303 /* Compare two string objects via strcmp() or alike.
 304  * Note that the objects may be integer-encoded. In such a case we
 305  * use ll2string() to get a string representation of the numbers on the stack
 306  * and compare the strings, it's much faster than calling getDecodedObject().
 307  *
 308  * Important note: if objects are not integer encoded, but binary-safe strings,
 309  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 310  * binary safe. */
 311 int compareStringObjects(robj *a, robj *b) {
 312     redisAssertWithInfo(NULL,a,a->type == REDIS_STRING && b->type == REDIS_STRING);
 313     char bufa[128], bufb[128], *astr, *bstr;
 314     int bothsds = 1;
 315
 316     if (a == b) return 0;
 317     if (a->encoding != REDIS_ENCODING_RAW) {
 318         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 319         astr = bufa;
 320         bothsds = 0;
 321     } else {
 322         astr = a->ptr;
 323     }
 324     if (b->encoding != REDIS_ENCODING_RAW) {
 325         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 326         bstr = bufb;
 327         bothsds = 0;
 328     } else {
 329         bstr = b->ptr;
 330     }
 331     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 332 }
 333
 334 /* Equal string objects return 1 if the two objects are the same from the
 335  * point of view of a string comparison, otherwise 0 is returned. Note that
 336  * this function is faster then checking for (compareStringObject(a,b) == 0)
 337  * because it can perform some more optimization. */
 338 int equalStringObjects(robj *a, robj *b) {
 339     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 340         return a->ptr == b->ptr;
 341     } else {
 342         return compareStringObjects(a,b) == 0;
 343     }
 344 }
 345
 346 size_t stringObjectLen(robj *o) {
 347     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 348     if (o->encoding == REDIS_ENCODING_RAW) {
 349         return sdslen(o->ptr);
 350     } else {
 351         char buf[32];
 352
 353         return ll2string(buf,32,(long)o->ptr);
 354     }
 355 }
 356
 357 int getDoubleFromObject(robj *o, double *target) {
 358     double value;
 359     char *eptr;
 360
 361     if (o == NULL) {
 362         value = 0;
 363     } else {
 364         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 365         if (o->encoding == REDIS_ENCODING_RAW) {
 366             errno = 0;
 367             value = strtod(o->ptr, &eptr);
 368             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 369                 errno == ERANGE || isnan(value))
 370                 return REDIS_ERR;
 371         } else if (o->encoding == REDIS_ENCODING_INT) {
 372             value = (long)o->ptr;
 373         } else {
 374             redisPanic("Unknown string encoding");
 375         }
 376     }
 377     *target = value;
 378     return REDIS_OK;
 379 }
 380
 381 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 382     double value;
 383     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 384         if (msg != NULL) {
 385             addReplyError(c,(char*)msg);
 386         } else {
 387             addReplyError(c,"value is not a valid float");
 388         }
 389         return REDIS_ERR;
 390     }
 391     *target = value;
 392     return REDIS_OK;
 393 }
 394
 395 int getLongDoubleFromObject(robj *o, long double *target) {
 396     long double value;
 397     char *eptr;
 398
 399     if (o == NULL) {
 400         value = 0;
 401     } else {
 402         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 403         if (o->encoding == REDIS_ENCODING_RAW) {
 404             errno = 0;
 405             value = strtold(o->ptr, &eptr);
 406             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 407                 errno == ERANGE || isnan(value))
 408                 return REDIS_ERR;
 409         } else if (o->encoding == REDIS_ENCODING_INT) {
 410             value = (long)o->ptr;
 411         } else {
 412             redisPanic("Unknown string encoding");
 413         }
 414     }
 415     *target = value;
 416     return REDIS_OK;
 417 }
 418
 419 int getLongDoubleFromObjectOrReply(redisClient *c, robj *o, long double *target, const char *msg) {
 420     long double value;
 421     if (getLongDoubleFromObject(o, &value) != REDIS_OK) {
 422         if (msg != NULL) {
 423             addReplyError(c,(char*)msg);
 424         } else {
 425             addReplyError(c,"value is not a valid float");
 426         }
 427         return REDIS_ERR;
 428     }
 429     *target = value;
 430     return REDIS_OK;
 431 }
 432
 433 int getLongLongFromObject(robj *o, long long *target) {
 434     long long value;
 435     char *eptr;
 436
 437     if (o == NULL) {
 438         value = 0;
 439     } else {
 440         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 441         if (o->encoding == REDIS_ENCODING_RAW) {
 442             errno = 0;
 443             value = strtoll(o->ptr, &eptr, 10);
 444             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 445                 errno == ERANGE)
 446                 return REDIS_ERR;
 447         } else if (o->encoding == REDIS_ENCODING_INT) {
 448             value = (long)o->ptr;
 449         } else {
 450             redisPanic("Unknown string encoding");
 451         }
 452     }
 453     if (target) *target = value;
 454     return REDIS_OK;
 455 }
 456
 457 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 458     long long value;
 459     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 460         if (msg != NULL) {
 461             addReplyError(c,(char*)msg);
 462         } else {
 463             addReplyError(c,"value is not an integer or out of range");
 464         }
 465         return REDIS_ERR;
 466     }
 467     *target = value;
 468     return REDIS_OK;
 469 }
 470
 471 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 472     long long value;
 473
 474     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 475     if (value < LONG_MIN || value > LONG_MAX) {
 476         if (msg != NULL) {
 477             addReplyError(c,(char*)msg);
 478         } else {
 479             addReplyError(c,"value is out of range");
 480         }
 481         return REDIS_ERR;
 482     }
 483     *target = value;
 484     return REDIS_OK;
 485 }
 486
 487 char *strEncoding(int encoding) {
 488     switch(encoding) {
 489     case REDIS_ENCODING_RAW: return "raw";
 490     case REDIS_ENCODING_INT: return "int";
 491     case REDIS_ENCODING_HT: return "hashtable";
 492     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 493     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 494     case REDIS_ENCODING_INTSET: return "intset";
 495     case REDIS_ENCODING_SKIPLIST: return "skiplist";
 496     default: return "unknown";
 497     }
 498 }
 499
 500 /* Given an object returns the min number of seconds the object was never
 501  * requested, using an approximated LRU algorithm. */
 502 unsigned long estimateObjectIdleTime(robj *o) {
 503     if (server.lruclock >= o->lru) {
 504         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 505     } else {
 506         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 507                     REDIS_LRU_CLOCK_RESOLUTION;
 508     }
 509 }
 510
 511 /* This is an helper function for the DEBUG command. We need to lookup keys
 512  * without any modification of LRU or other parameters. */
 513 robj *objectCommandLookup(redisClient *c, robj *key) {
 514     dictEntry *de;
 515
 516     if ((de = dictFind(c->db->dict,key->ptr)) == NULL) return NULL;
 517     return (robj*) dictGetVal(de);
 518 }
 519
 520 robj *objectCommandLookupOrReply(redisClient *c, robj *key, robj *reply) {
 521     robj *o = objectCommandLookup(c,key);
 522
 523     if (!o) addReply(c, reply);
 524     return o;
 525 }
 526
 527 /* Object command allows to inspect the internals of an Redis Object.
 528  * Usage: OBJECT <verb> ... arguments ... */
 529 void objectCommand(redisClient *c) {
 530     robj *o;
 531
 532     if (!strcasecmp(c->argv[1]->ptr,"refcount") && c->argc == 3) {
 533         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 534                 == NULL) return;
 535         addReplyLongLong(c,o->refcount);
 536     } else if (!strcasecmp(c->argv[1]->ptr,"encoding") && c->argc == 3) {
 537         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 538                 == NULL) return;
 539         addReplyBulkCString(c,strEncoding(o->encoding));
 540     } else if (!strcasecmp(c->argv[1]->ptr,"idletime") && c->argc == 3) {
 541         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 542                 == NULL) return;
 543         addReplyLongLong(c,estimateObjectIdleTime(o));
 544     } else {
 545         addReplyError(c,"Syntax error. Try OBJECT (refcount|encoding|idletime)");
 546     }
 547 }
 548