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], *p;
  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),"%.17Lf", value);
  60     /* Now remove trailing zeroes after the '.' */
  61     if ((p = strchr(buf,'.')) != NULL) {
  62         p = buf+len-1;
  63         while(*p == '0') {
  64             p--;
  65             len--;
  66         }
  67         if (*p == '.') len--;
  68     }
  69     return createStringObject(buf,len);
  70 }
  71
  72 robj *dupStringObject(robj *o) {
  73     redisAssertWithInfo(NULL,o,o->encoding == REDIS_ENCODING_RAW);
  74     return createStringObject(o->ptr,sdslen(o->ptr));
  75 }
  76
  77 robj *createListObject(void) {
  78     list *l = listCreate();
  79     robj *o = createObject(REDIS_LIST,l);
  80     listSetFreeMethod(l,decrRefCount);
  81     o->encoding = REDIS_ENCODING_LINKEDLIST;
  82     return o;
  83 }
  84
  85 robj *createZiplistObject(void) {
  86     unsigned char *zl = ziplistNew();
  87     robj *o = createObject(REDIS_LIST,zl);
  88     o->encoding = REDIS_ENCODING_ZIPLIST;
  89     return o;
  90 }
  91
  92 robj *createSetObject(void) {
  93     dict *d = dictCreate(&setDictType,NULL);
  94     robj *o = createObject(REDIS_SET,d);
  95     o->encoding = REDIS_ENCODING_HT;
  96     return o;
  97 }
  98
  99 robj *createIntsetObject(void) {
 100     intset *is = intsetNew();
 101     robj *o = createObject(REDIS_SET,is);
 102     o->encoding = REDIS_ENCODING_INTSET;
 103     return o;
 104 }
 105
 106 robj *createHashObject(void) {
 107     unsigned char *zl = ziplistNew();
 108     robj *o = createObject(REDIS_HASH, zl);
 109     o->encoding = REDIS_ENCODING_ZIPLIST;
 110     return o;
 111 }
 112
 113 robj *createZsetObject(void) {
 114     zset *zs = zmalloc(sizeof(*zs));
 115     robj *o;
 116
 117     zs->dict = dictCreate(&zsetDictType,NULL);
 118     zs->zsl = zslCreate();
 119     o = createObject(REDIS_ZSET,zs);
 120     o->encoding = REDIS_ENCODING_SKIPLIST;
 121     return o;
 122 }
 123
 124 robj *createZsetZiplistObject(void) {
 125     unsigned char *zl = ziplistNew();
 126     robj *o = createObject(REDIS_ZSET,zl);
 127     o->encoding = REDIS_ENCODING_ZIPLIST;
 128     return o;
 129 }
 130
 131 void freeStringObject(robj *o) {
 132     if (o->encoding == REDIS_ENCODING_RAW) {
 133         sdsfree(o->ptr);
 134     }
 135 }
 136
 137 void freeListObject(robj *o) {
 138     switch (o->encoding) {
 139     case REDIS_ENCODING_LINKEDLIST:
 140         listRelease((list*) o->ptr);
 141         break;
 142     case REDIS_ENCODING_ZIPLIST:
 143         zfree(o->ptr);
 144         break;
 145     default:
 146         redisPanic("Unknown list encoding type");
 147     }
 148 }
 149
 150 void freeSetObject(robj *o) {
 151     switch (o->encoding) {
 152     case REDIS_ENCODING_HT:
 153         dictRelease((dict*) o->ptr);
 154         break;
 155     case REDIS_ENCODING_INTSET:
 156         zfree(o->ptr);
 157         break;
 158     default:
 159         redisPanic("Unknown set encoding type");
 160     }
 161 }
 162
 163 void freeZsetObject(robj *o) {
 164     zset *zs;
 165     switch (o->encoding) {
 166     case REDIS_ENCODING_SKIPLIST:
 167         zs = o->ptr;
 168         dictRelease(zs->dict);
 169         zslFree(zs->zsl);
 170         zfree(zs);
 171         break;
 172     case REDIS_ENCODING_ZIPLIST:
 173         zfree(o->ptr);
 174         break;
 175     default:
 176         redisPanic("Unknown sorted set encoding");
 177     }
 178 }
 179
 180 void freeHashObject(robj *o) {
 181     switch (o->encoding) {
 182     case REDIS_ENCODING_HT:
 183         dictRelease((dict*) o->ptr);
 184         break;
 185     case REDIS_ENCODING_ZIPLIST:
 186         zfree(o->ptr);
 187         break;
 188     default:
 189         redisPanic("Unknown hash encoding type");
 190         break;
 191     }
 192 }
 193
 194 void incrRefCount(robj *o) {
 195     o->refcount++;
 196 }
 197
 198 void decrRefCount(void *obj) {
 199     robj *o = obj;
 200
 201     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 202     if (o->refcount == 1) {
 203         switch(o->type) {
 204         case REDIS_STRING: freeStringObject(o); break;
 205         case REDIS_LIST: freeListObject(o); break;
 206         case REDIS_SET: freeSetObject(o); break;
 207         case REDIS_ZSET: freeZsetObject(o); break;
 208         case REDIS_HASH: freeHashObject(o); break;
 209         default: redisPanic("Unknown object type"); break;
 210         }
 211         zfree(o);
 212     } else {
 213         o->refcount--;
 214     }
 215 }
 216
 217 /* This function set the ref count to zero without freeing the object.
 218  * It is useful in order to pass a new object to functions incrementing
 219  * the ref count of the received object. Example:
 220  *
 221  *    functionThatWillIncrementRefCount(resetRefCount(CreateObject(...)));
 222  *
 223  * Otherwise you need to resort to the less elegant pattern:
 224  *
 225  *    *obj = createObject(...);
 226  *    functionThatWillIncrementRefCount(obj);
 227  *    decrRefCount(obj);
 228  */
 229 robj *resetRefCount(robj *obj) {
 230     obj->refcount = 0;
 231     return obj;
 232 }
 233
 234 int checkType(redisClient *c, robj *o, int type) {
 235     if (o->type != type) {
 236         addReply(c,shared.wrongtypeerr);
 237         return 1;
 238     }
 239     return 0;
 240 }
 241
 242 int isObjectRepresentableAsLongLong(robj *o, long long *llval) {
 243     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 244     if (o->encoding == REDIS_ENCODING_INT) {
 245         if (llval) *llval = (long) o->ptr;
 246         return REDIS_OK;
 247     } else {
 248         return string2ll(o->ptr,sdslen(o->ptr),llval) ? REDIS_OK : REDIS_ERR;
 249     }
 250 }
 251
 252 /* Try to encode a string object in order to save space */
 253 robj *tryObjectEncoding(robj *o) {
 254     long value;
 255     sds s = o->ptr;
 256
 257     if (o->encoding != REDIS_ENCODING_RAW)
 258         return o; /* Already encoded */
 259
 260     /* It's not safe to encode shared objects: shared objects can be shared
 261      * everywhere in the "object space" of Redis. Encoded objects can only
 262      * appear as "values" (and not, for instance, as keys) */
 263      if (o->refcount > 1) return o;
 264
 265     /* Currently we try to encode only strings */
 266     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 267
 268     /* Check if we can represent this string as a long integer */
 269     if (!string2l(s,sdslen(s),&value)) return o;
 270
 271     /* Ok, this object can be encoded...
 272      *
 273      * Can I use a shared object? Only if the object is inside a given
 274      * range and if the back end in use is in-memory. For disk store every
 275      * object in memory used as value should be independent.
 276      *
 277      * Note that we also avoid using shared integers when maxmemory is used
 278      * because every object needs to have a private LRU field for the LRU
 279      * algorithm to work well. */
 280     if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS) {
 281         decrRefCount(o);
 282         incrRefCount(shared.integers[value]);
 283         return shared.integers[value];
 284     } else {
 285         o->encoding = REDIS_ENCODING_INT;
 286         sdsfree(o->ptr);
 287         o->ptr = (void*) value;
 288         return o;
 289     }
 290 }
 291
 292 /* Get a decoded version of an encoded object (returned as a new object).
 293  * If the object is already raw-encoded just increment the ref count. */
 294 robj *getDecodedObject(robj *o) {
 295     robj *dec;
 296
 297     if (o->encoding == REDIS_ENCODING_RAW) {
 298         incrRefCount(o);
 299         return o;
 300     }
 301     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 302         char buf[32];
 303
 304         ll2string(buf,32,(long)o->ptr);
 305         dec = createStringObject(buf,strlen(buf));
 306         return dec;
 307     } else {
 308         redisPanic("Unknown encoding type");
 309     }
 310 }
 311
 312 /* Compare two string objects via strcmp() or alike.
 313  * Note that the objects may be integer-encoded. In such a case we
 314  * use ll2string() to get a string representation of the numbers on the stack
 315  * and compare the strings, it's much faster than calling getDecodedObject().
 316  *
 317  * Important note: if objects are not integer encoded, but binary-safe strings,
 318  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 319  * binary safe. */
 320 int compareStringObjects(robj *a, robj *b) {
 321     redisAssertWithInfo(NULL,a,a->type == REDIS_STRING && b->type == REDIS_STRING);
 322     char bufa[128], bufb[128], *astr, *bstr;
 323     int bothsds = 1;
 324
 325     if (a == b) return 0;
 326     if (a->encoding != REDIS_ENCODING_RAW) {
 327         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 328         astr = bufa;
 329         bothsds = 0;
 330     } else {
 331         astr = a->ptr;
 332     }
 333     if (b->encoding != REDIS_ENCODING_RAW) {
 334         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 335         bstr = bufb;
 336         bothsds = 0;
 337     } else {
 338         bstr = b->ptr;
 339     }
 340     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 341 }
 342
 343 /* Equal string objects return 1 if the two objects are the same from the
 344  * point of view of a string comparison, otherwise 0 is returned. Note that
 345  * this function is faster then checking for (compareStringObject(a,b) == 0)
 346  * because it can perform some more optimization. */
 347 int equalStringObjects(robj *a, robj *b) {
 348     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 349         return a->ptr == b->ptr;
 350     } else {
 351         return compareStringObjects(a,b) == 0;
 352     }
 353 }
 354
 355 size_t stringObjectLen(robj *o) {
 356     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 357     if (o->encoding == REDIS_ENCODING_RAW) {
 358         return sdslen(o->ptr);
 359     } else {
 360         char buf[32];
 361
 362         return ll2string(buf,32,(long)o->ptr);
 363     }
 364 }
 365
 366 int getDoubleFromObject(robj *o, double *target) {
 367     double value;
 368     char *eptr;
 369
 370     if (o == NULL) {
 371         value = 0;
 372     } else {
 373         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 374         if (o->encoding == REDIS_ENCODING_RAW) {
 375             errno = 0;
 376             value = strtod(o->ptr, &eptr);
 377             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 378                 errno == ERANGE || isnan(value))
 379                 return REDIS_ERR;
 380         } else if (o->encoding == REDIS_ENCODING_INT) {
 381             value = (long)o->ptr;
 382         } else {
 383             redisPanic("Unknown string encoding");
 384         }
 385     }
 386     *target = value;
 387     return REDIS_OK;
 388 }
 389
 390 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 391     double value;
 392     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 393         if (msg != NULL) {
 394             addReplyError(c,(char*)msg);
 395         } else {
 396             addReplyError(c,"value is not a valid float");
 397         }
 398         return REDIS_ERR;
 399     }
 400     *target = value;
 401     return REDIS_OK;
 402 }
 403
 404 int getLongDoubleFromObject(robj *o, long double *target) {
 405     long double value;
 406     char *eptr;
 407
 408     if (o == NULL) {
 409         value = 0;
 410     } else {
 411         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 412         if (o->encoding == REDIS_ENCODING_RAW) {
 413             errno = 0;
 414             value = strtold(o->ptr, &eptr);
 415             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 416                 errno == ERANGE || isnan(value))
 417                 return REDIS_ERR;
 418         } else if (o->encoding == REDIS_ENCODING_INT) {
 419             value = (long)o->ptr;
 420         } else {
 421             redisPanic("Unknown string encoding");
 422         }
 423     }
 424     *target = value;
 425     return REDIS_OK;
 426 }
 427
 428 int getLongDoubleFromObjectOrReply(redisClient *c, robj *o, long double *target, const char *msg) {
 429     long double value;
 430     if (getLongDoubleFromObject(o, &value) != REDIS_OK) {
 431         if (msg != NULL) {
 432             addReplyError(c,(char*)msg);
 433         } else {
 434             addReplyError(c,"value is not a valid float");
 435         }
 436         return REDIS_ERR;
 437     }
 438     *target = value;
 439     return REDIS_OK;
 440 }
 441
 442 int getLongLongFromObject(robj *o, long long *target) {
 443     long long value;
 444     char *eptr;
 445
 446     if (o == NULL) {
 447         value = 0;
 448     } else {
 449         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 450         if (o->encoding == REDIS_ENCODING_RAW) {
 451             errno = 0;
 452             value = strtoll(o->ptr, &eptr, 10);
 453             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 454                 errno == ERANGE)
 455                 return REDIS_ERR;
 456         } else if (o->encoding == REDIS_ENCODING_INT) {
 457             value = (long)o->ptr;
 458         } else {
 459             redisPanic("Unknown string encoding");
 460         }
 461     }
 462     if (target) *target = value;
 463     return REDIS_OK;
 464 }
 465
 466 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 467     long long value;
 468     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 469         if (msg != NULL) {
 470             addReplyError(c,(char*)msg);
 471         } else {
 472             addReplyError(c,"value is not an integer or out of range");
 473         }
 474         return REDIS_ERR;
 475     }
 476     *target = value;
 477     return REDIS_OK;
 478 }
 479
 480 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 481     long long value;
 482
 483     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 484     if (value < LONG_MIN || value > LONG_MAX) {
 485         if (msg != NULL) {
 486             addReplyError(c,(char*)msg);
 487         } else {
 488             addReplyError(c,"value is out of range");
 489         }
 490         return REDIS_ERR;
 491     }
 492     *target = value;
 493     return REDIS_OK;
 494 }
 495
 496 char *strEncoding(int encoding) {
 497     switch(encoding) {
 498     case REDIS_ENCODING_RAW: return "raw";
 499     case REDIS_ENCODING_INT: return "int";
 500     case REDIS_ENCODING_HT: return "hashtable";
 501     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 502     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 503     case REDIS_ENCODING_INTSET: return "intset";
 504     case REDIS_ENCODING_SKIPLIST: return "skiplist";
 505     default: return "unknown";
 506     }
 507 }
 508
 509 /* Given an object returns the min number of seconds the object was never
 510  * requested, using an approximated LRU algorithm. */
 511 unsigned long estimateObjectIdleTime(robj *o) {
 512     if (server.lruclock >= o->lru) {
 513         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 514     } else {
 515         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 516                     REDIS_LRU_CLOCK_RESOLUTION;
 517     }
 518 }
 519
 520 /* This is an helper function for the DEBUG command. We need to lookup keys
 521  * without any modification of LRU or other parameters. */
 522 robj *objectCommandLookup(redisClient *c, robj *key) {
 523     dictEntry *de;
 524
 525     if ((de = dictFind(c->db->dict,key->ptr)) == NULL) return NULL;
 526     return (robj*) dictGetVal(de);
 527 }
 528
 529 robj *objectCommandLookupOrReply(redisClient *c, robj *key, robj *reply) {
 530     robj *o = objectCommandLookup(c,key);
 531
 532     if (!o) addReply(c, reply);
 533     return o;
 534 }
 535
 536 /* Object command allows to inspect the internals of an Redis Object.
 537  * Usage: OBJECT <verb> ... arguments ... */
 538 void objectCommand(redisClient *c) {
 539     robj *o;
 540
 541     if (!strcasecmp(c->argv[1]->ptr,"refcount") && c->argc == 3) {
 542         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 543                 == NULL) return;
 544         addReplyLongLong(c,o->refcount);
 545     } else if (!strcasecmp(c->argv[1]->ptr,"encoding") && c->argc == 3) {
 546         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 547                 == NULL) return;
 548         addReplyBulkCString(c,strEncoding(o->encoding));
 549     } else if (!strcasecmp(c->argv[1]->ptr,"idletime") && c->argc == 3) {
 550         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 551                 == NULL) return;
 552         addReplyLongLong(c,estimateObjectIdleTime(o));
 553     } else {
 554         addReplyError(c,"Syntax error. Try OBJECT (refcount|encoding|idletime)");
 555     }
 556 }
 557