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),"%.17Lf", value);
  60     /* Now remove trailing zeroes after the '.' */
  61     if (strchr(buf,'.') != NULL) {
  62         char *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 range
 274      *
 275      * Note that we also avoid using shared integers when maxmemory is used
 276      * because every object needs to have a private LRU field for the LRU
 277      * algorithm to work well. */
 278     if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS) {
 279         decrRefCount(o);
 280         incrRefCount(shared.integers[value]);
 281         return shared.integers[value];
 282     } else {
 283         o->encoding = REDIS_ENCODING_INT;
 284         sdsfree(o->ptr);
 285         o->ptr = (void*) value;
 286         return o;
 287     }
 288 }
 289
 290 /* Get a decoded version of an encoded object (returned as a new object).
 291  * If the object is already raw-encoded just increment the ref count. */
 292 robj *getDecodedObject(robj *o) {
 293     robj *dec;
 294
 295     if (o->encoding == REDIS_ENCODING_RAW) {
 296         incrRefCount(o);
 297         return o;
 298     }
 299     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 300         char buf[32];
 301
 302         ll2string(buf,32,(long)o->ptr);
 303         dec = createStringObject(buf,strlen(buf));
 304         return dec;
 305     } else {
 306         redisPanic("Unknown encoding type");
 307     }
 308 }
 309
 310 /* Compare two string objects via strcmp() or alike.
 311  * Note that the objects may be integer-encoded. In such a case we
 312  * use ll2string() to get a string representation of the numbers on the stack
 313  * and compare the strings, it's much faster than calling getDecodedObject().
 314  *
 315  * Important note: if objects are not integer encoded, but binary-safe strings,
 316  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 317  * binary safe. */
 318 int compareStringObjects(robj *a, robj *b) {
 319     redisAssertWithInfo(NULL,a,a->type == REDIS_STRING && b->type == REDIS_STRING);
 320     char bufa[128], bufb[128], *astr, *bstr;
 321     int bothsds = 1;
 322
 323     if (a == b) return 0;
 324     if (a->encoding != REDIS_ENCODING_RAW) {
 325         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 326         astr = bufa;
 327         bothsds = 0;
 328     } else {
 329         astr = a->ptr;
 330     }
 331     if (b->encoding != REDIS_ENCODING_RAW) {
 332         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 333         bstr = bufb;
 334         bothsds = 0;
 335     } else {
 336         bstr = b->ptr;
 337     }
 338     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 339 }
 340
 341 /* Equal string objects return 1 if the two objects are the same from the
 342  * point of view of a string comparison, otherwise 0 is returned. Note that
 343  * this function is faster then checking for (compareStringObject(a,b) == 0)
 344  * because it can perform some more optimization. */
 345 int equalStringObjects(robj *a, robj *b) {
 346     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 347         return a->ptr == b->ptr;
 348     } else {
 349         return compareStringObjects(a,b) == 0;
 350     }
 351 }
 352
 353 size_t stringObjectLen(robj *o) {
 354     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 355     if (o->encoding == REDIS_ENCODING_RAW) {
 356         return sdslen(o->ptr);
 357     } else {
 358         char buf[32];
 359
 360         return ll2string(buf,32,(long)o->ptr);
 361     }
 362 }
 363
 364 int getDoubleFromObject(robj *o, double *target) {
 365     double value;
 366     char *eptr;
 367
 368     if (o == NULL) {
 369         value = 0;
 370     } else {
 371         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 372         if (o->encoding == REDIS_ENCODING_RAW) {
 373             errno = 0;
 374             value = strtod(o->ptr, &eptr);
 375             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 376                 errno == ERANGE || isnan(value))
 377                 return REDIS_ERR;
 378         } else if (o->encoding == REDIS_ENCODING_INT) {
 379             value = (long)o->ptr;
 380         } else {
 381             redisPanic("Unknown string encoding");
 382         }
 383     }
 384     *target = value;
 385     return REDIS_OK;
 386 }
 387
 388 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 389     double value;
 390     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 391         if (msg != NULL) {
 392             addReplyError(c,(char*)msg);
 393         } else {
 394             addReplyError(c,"value is not a valid float");
 395         }
 396         return REDIS_ERR;
 397     }
 398     *target = value;
 399     return REDIS_OK;
 400 }
 401
 402 int getLongDoubleFromObject(robj *o, long double *target) {
 403     long double value;
 404     char *eptr;
 405
 406     if (o == NULL) {
 407         value = 0;
 408     } else {
 409         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 410         if (o->encoding == REDIS_ENCODING_RAW) {
 411             errno = 0;
 412             value = strtold(o->ptr, &eptr);
 413             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 414                 errno == ERANGE || isnan(value))
 415                 return REDIS_ERR;
 416         } else if (o->encoding == REDIS_ENCODING_INT) {
 417             value = (long)o->ptr;
 418         } else {
 419             redisPanic("Unknown string encoding");
 420         }
 421     }
 422     *target = value;
 423     return REDIS_OK;
 424 }
 425
 426 int getLongDoubleFromObjectOrReply(redisClient *c, robj *o, long double *target, const char *msg) {
 427     long double value;
 428     if (getLongDoubleFromObject(o, &value) != REDIS_OK) {
 429         if (msg != NULL) {
 430             addReplyError(c,(char*)msg);
 431         } else {
 432             addReplyError(c,"value is not a valid float");
 433         }
 434         return REDIS_ERR;
 435     }
 436     *target = value;
 437     return REDIS_OK;
 438 }
 439
 440 int getLongLongFromObject(robj *o, long long *target) {
 441     long long value;
 442     char *eptr;
 443
 444     if (o == NULL) {
 445         value = 0;
 446     } else {
 447         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 448         if (o->encoding == REDIS_ENCODING_RAW) {
 449             errno = 0;
 450             value = strtoll(o->ptr, &eptr, 10);
 451             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 452                 errno == ERANGE)
 453                 return REDIS_ERR;
 454         } else if (o->encoding == REDIS_ENCODING_INT) {
 455             value = (long)o->ptr;
 456         } else {
 457             redisPanic("Unknown string encoding");
 458         }
 459     }
 460     if (target) *target = value;
 461     return REDIS_OK;
 462 }
 463
 464 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 465     long long value;
 466     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 467         if (msg != NULL) {
 468             addReplyError(c,(char*)msg);
 469         } else {
 470             addReplyError(c,"value is not an integer or out of range");
 471         }
 472         return REDIS_ERR;
 473     }
 474     *target = value;
 475     return REDIS_OK;
 476 }
 477
 478 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 479     long long value;
 480
 481     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 482     if (value < LONG_MIN || value > LONG_MAX) {
 483         if (msg != NULL) {
 484             addReplyError(c,(char*)msg);
 485         } else {
 486             addReplyError(c,"value is out of range");
 487         }
 488         return REDIS_ERR;
 489     }
 490     *target = value;
 491     return REDIS_OK;
 492 }
 493
 494 char *strEncoding(int encoding) {
 495     switch(encoding) {
 496     case REDIS_ENCODING_RAW: return "raw";
 497     case REDIS_ENCODING_INT: return "int";
 498     case REDIS_ENCODING_HT: return "hashtable";
 499     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 500     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 501     case REDIS_ENCODING_INTSET: return "intset";
 502     case REDIS_ENCODING_SKIPLIST: return "skiplist";
 503     default: return "unknown";
 504     }
 505 }
 506
 507 /* Given an object returns the min number of seconds the object was never
 508  * requested, using an approximated LRU algorithm. */
 509 unsigned long estimateObjectIdleTime(robj *o) {
 510     if (server.lruclock >= o->lru) {
 511         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 512     } else {
 513         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 514                     REDIS_LRU_CLOCK_RESOLUTION;
 515     }
 516 }
 517
 518 /* This is an helper function for the DEBUG command. We need to lookup keys
 519  * without any modification of LRU or other parameters. */
 520 robj *objectCommandLookup(redisClient *c, robj *key) {
 521     dictEntry *de;
 522
 523     if ((de = dictFind(c->db->dict,key->ptr)) == NULL) return NULL;
 524     return (robj*) dictGetVal(de);
 525 }
 526
 527 robj *objectCommandLookupOrReply(redisClient *c, robj *key, robj *reply) {
 528     robj *o = objectCommandLookup(c,key);
 529
 530     if (!o) addReply(c, reply);
 531     return o;
 532 }
 533
 534 /* Object command allows to inspect the internals of an Redis Object.
 535  * Usage: OBJECT <verb> ... arguments ... */
 536 void objectCommand(redisClient *c) {
 537     robj *o;
 538
 539     if (!strcasecmp(c->argv[1]->ptr,"refcount") && c->argc == 3) {
 540         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 541                 == NULL) return;
 542         addReplyLongLong(c,o->refcount);
 543     } else if (!strcasecmp(c->argv[1]->ptr,"encoding") && c->argc == 3) {
 544         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 545                 == NULL) return;
 546         addReplyBulkCString(c,strEncoding(o->encoding));
 547     } else if (!strcasecmp(c->argv[1]->ptr,"idletime") && c->argc == 3) {
 548         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 549                 == NULL) return;
 550         addReplyLongLong(c,estimateObjectIdleTime(o));
 551     } else {
 552         addReplyError(c,"Syntax error. Try OBJECT (refcount|encoding|idletime)");
 553     }
 554 }
 555