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     o->lru = server.lruclock;
  14     return o;
  15 }
  16
  17 robj *createStringObject(char *ptr, size_t len) {
  18     return createObject(REDIS_STRING,sdsnewlen(ptr,len));
  19 }
  20
  21 robj *createStringObjectFromLongLong(long long value) {
  22     robj *o;
  23     if (value >= 0 && value < REDIS_SHARED_INTEGERS) {
  24         incrRefCount(shared.integers[value]);
  25         o = shared.integers[value];
  26     } else {
  27         if (value >= LONG_MIN && value <= LONG_MAX) {
  28             o = createObject(REDIS_STRING, NULL);
  29             o->encoding = REDIS_ENCODING_INT;
  30             o->ptr = (void*)((long)value);
  31         } else {
  32             o = createObject(REDIS_STRING,sdsfromlonglong(value));
  33         }
  34     }
  35     return o;
  36 }
  37
  38 /* Note: this function is defined into object.c since here it is where it
  39  * belongs but it is actually designed to be used just for INCRBYFLOAT */
  40 robj *createStringObjectFromLongDouble(long double value) {
  41     char buf[256];
  42     int len;
  43
  44     /* We use 17 digits precision since with 128 bit floats that precision
  45      * after rouding is able to represent most small decimal numbers in a way
  46      * that is "non surprising" for the user (that is, most small decimal
  47      * numbers will be represented in a way that when converted back into
  48      * a string are exactly the same as what the user typed.) */
  49     len = snprintf(buf,sizeof(buf),"%.17Lf", value);
  50     /* Now remove trailing zeroes after the '.' */
  51     if (strchr(buf,'.') != NULL) {
  52         char *p = buf+len-1;
  53         while(*p == '0') {
  54             p--;
  55             len--;
  56         }
  57         if (*p == '.') len--;
  58     }
  59     return createStringObject(buf,len);
  60 }
  61
  62 robj *dupStringObject(robj *o) {
  63     redisAssertWithInfo(NULL,o,o->encoding == REDIS_ENCODING_RAW);
  64     return createStringObject(o->ptr,sdslen(o->ptr));
  65 }
  66
  67 robj *createListObject(void) {
  68     list *l = listCreate();
  69     robj *o = createObject(REDIS_LIST,l);
  70     listSetFreeMethod(l,decrRefCount);
  71     o->encoding = REDIS_ENCODING_LINKEDLIST;
  72     return o;
  73 }
  74
  75 robj *createZiplistObject(void) {
  76     unsigned char *zl = ziplistNew();
  77     robj *o = createObject(REDIS_LIST,zl);
  78     o->encoding = REDIS_ENCODING_ZIPLIST;
  79     return o;
  80 }
  81
  82 robj *createSetObject(void) {
  83     dict *d = dictCreate(&setDictType,NULL);
  84     robj *o = createObject(REDIS_SET,d);
  85     o->encoding = REDIS_ENCODING_HT;
  86     return o;
  87 }
  88
  89 robj *createIntsetObject(void) {
  90     intset *is = intsetNew();
  91     robj *o = createObject(REDIS_SET,is);
  92     o->encoding = REDIS_ENCODING_INTSET;
  93     return o;
  94 }
  95
  96 robj *createHashObject(void) {
  97     unsigned char *zl = ziplistNew();
  98     robj *o = createObject(REDIS_HASH, zl);
  99     o->encoding = REDIS_ENCODING_ZIPLIST;
 100     return o;
 101 }
 102
 103 robj *createZsetObject(void) {
 104     zset *zs = zmalloc(sizeof(*zs));
 105     robj *o;
 106
 107     zs->dict = dictCreate(&zsetDictType,NULL);
 108     zs->zsl = zslCreate();
 109     o = createObject(REDIS_ZSET,zs);
 110     o->encoding = REDIS_ENCODING_SKIPLIST;
 111     return o;
 112 }
 113
 114 robj *createZsetZiplistObject(void) {
 115     unsigned char *zl = ziplistNew();
 116     robj *o = createObject(REDIS_ZSET,zl);
 117     o->encoding = REDIS_ENCODING_ZIPLIST;
 118     return o;
 119 }
 120
 121 void freeStringObject(robj *o) {
 122     if (o->encoding == REDIS_ENCODING_RAW) {
 123         sdsfree(o->ptr);
 124     }
 125 }
 126
 127 void freeListObject(robj *o) {
 128     switch (o->encoding) {
 129     case REDIS_ENCODING_LINKEDLIST:
 130         listRelease((list*) o->ptr);
 131         break;
 132     case REDIS_ENCODING_ZIPLIST:
 133         zfree(o->ptr);
 134         break;
 135     default:
 136         redisPanic("Unknown list encoding type");
 137     }
 138 }
 139
 140 void freeSetObject(robj *o) {
 141     switch (o->encoding) {
 142     case REDIS_ENCODING_HT:
 143         dictRelease((dict*) o->ptr);
 144         break;
 145     case REDIS_ENCODING_INTSET:
 146         zfree(o->ptr);
 147         break;
 148     default:
 149         redisPanic("Unknown set encoding type");
 150     }
 151 }
 152
 153 void freeZsetObject(robj *o) {
 154     zset *zs;
 155     switch (o->encoding) {
 156     case REDIS_ENCODING_SKIPLIST:
 157         zs = o->ptr;
 158         dictRelease(zs->dict);
 159         zslFree(zs->zsl);
 160         zfree(zs);
 161         break;
 162     case REDIS_ENCODING_ZIPLIST:
 163         zfree(o->ptr);
 164         break;
 165     default:
 166         redisPanic("Unknown sorted set encoding");
 167     }
 168 }
 169
 170 void freeHashObject(robj *o) {
 171     switch (o->encoding) {
 172     case REDIS_ENCODING_HT:
 173         dictRelease((dict*) o->ptr);
 174         break;
 175     case REDIS_ENCODING_ZIPLIST:
 176         zfree(o->ptr);
 177         break;
 178     default:
 179         redisPanic("Unknown hash encoding type");
 180         break;
 181     }
 182 }
 183
 184 void incrRefCount(robj *o) {
 185     o->refcount++;
 186 }
 187
 188 void decrRefCount(void *obj) {
 189     robj *o = obj;
 190
 191     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 192     if (o->refcount == 1) {
 193         switch(o->type) {
 194         case REDIS_STRING: freeStringObject(o); break;
 195         case REDIS_LIST: freeListObject(o); break;
 196         case REDIS_SET: freeSetObject(o); break;
 197         case REDIS_ZSET: freeZsetObject(o); break;
 198         case REDIS_HASH: freeHashObject(o); break;
 199         default: redisPanic("Unknown object type"); break;
 200         }
 201         zfree(o);
 202     } else {
 203         o->refcount--;
 204     }
 205 }
 206
 207 /* This function set the ref count to zero without freeing the object.
 208  * It is useful in order to pass a new object to functions incrementing
 209  * the ref count of the received object. Example:
 210  *
 211  *    functionThatWillIncrementRefCount(resetRefCount(CreateObject(...)));
 212  *
 213  * Otherwise you need to resort to the less elegant pattern:
 214  *
 215  *    *obj = createObject(...);
 216  *    functionThatWillIncrementRefCount(obj);
 217  *    decrRefCount(obj);
 218  */
 219 robj *resetRefCount(robj *obj) {
 220     obj->refcount = 0;
 221     return obj;
 222 }
 223
 224 int checkType(redisClient *c, robj *o, int type) {
 225     if (o->type != type) {
 226         addReply(c,shared.wrongtypeerr);
 227         return 1;
 228     }
 229     return 0;
 230 }
 231
 232 int isObjectRepresentableAsLongLong(robj *o, long long *llval) {
 233     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 234     if (o->encoding == REDIS_ENCODING_INT) {
 235         if (llval) *llval = (long) o->ptr;
 236         return REDIS_OK;
 237     } else {
 238         return string2ll(o->ptr,sdslen(o->ptr),llval) ? REDIS_OK : REDIS_ERR;
 239     }
 240 }
 241
 242 /* Try to encode a string object in order to save space */
 243 robj *tryObjectEncoding(robj *o) {
 244     long value;
 245     sds s = o->ptr;
 246
 247     if (o->encoding != REDIS_ENCODING_RAW)
 248         return o; /* Already encoded */
 249
 250     /* It's not safe to encode shared objects: shared objects can be shared
 251      * everywhere in the "object space" of Redis. Encoded objects can only
 252      * appear as "values" (and not, for instance, as keys) */
 253      if (o->refcount > 1) return o;
 254
 255     /* Currently we try to encode only strings */
 256     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 257
 258     /* Check if we can represent this string as a long integer */
 259     if (!string2l(s,sdslen(s),&value)) return o;
 260
 261     /* Ok, this object can be encoded...
 262      *
 263      * Can I use a shared object? Only if the object is inside a given range
 264      *
 265      * Note that we also avoid using shared integers when maxmemory is used
 266      * because every object needs to have a private LRU field for the LRU
 267      * algorithm to work well. */
 268     if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS) {
 269         decrRefCount(o);
 270         incrRefCount(shared.integers[value]);
 271         return shared.integers[value];
 272     } else {
 273         o->encoding = REDIS_ENCODING_INT;
 274         sdsfree(o->ptr);
 275         o->ptr = (void*) value;
 276         return o;
 277     }
 278 }
 279
 280 /* Get a decoded version of an encoded object (returned as a new object).
 281  * If the object is already raw-encoded just increment the ref count. */
 282 robj *getDecodedObject(robj *o) {
 283     robj *dec;
 284
 285     if (o->encoding == REDIS_ENCODING_RAW) {
 286         incrRefCount(o);
 287         return o;
 288     }
 289     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 290         char buf[32];
 291
 292         ll2string(buf,32,(long)o->ptr);
 293         dec = createStringObject(buf,strlen(buf));
 294         return dec;
 295     } else {
 296         redisPanic("Unknown encoding type");
 297     }
 298 }
 299
 300 /* Compare two string objects via strcmp() or alike.
 301  * Note that the objects may be integer-encoded. In such a case we
 302  * use ll2string() to get a string representation of the numbers on the stack
 303  * and compare the strings, it's much faster than calling getDecodedObject().
 304  *
 305  * Important note: if objects are not integer encoded, but binary-safe strings,
 306  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 307  * binary safe. */
 308 int compareStringObjects(robj *a, robj *b) {
 309     redisAssertWithInfo(NULL,a,a->type == REDIS_STRING && b->type == REDIS_STRING);
 310     char bufa[128], bufb[128], *astr, *bstr;
 311     int bothsds = 1;
 312
 313     if (a == b) return 0;
 314     if (a->encoding != REDIS_ENCODING_RAW) {
 315         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 316         astr = bufa;
 317         bothsds = 0;
 318     } else {
 319         astr = a->ptr;
 320     }
 321     if (b->encoding != REDIS_ENCODING_RAW) {
 322         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 323         bstr = bufb;
 324         bothsds = 0;
 325     } else {
 326         bstr = b->ptr;
 327     }
 328     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 329 }
 330
 331 /* Equal string objects return 1 if the two objects are the same from the
 332  * point of view of a string comparison, otherwise 0 is returned. Note that
 333  * this function is faster then checking for (compareStringObject(a,b) == 0)
 334  * because it can perform some more optimization. */
 335 int equalStringObjects(robj *a, robj *b) {
 336     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 337         return a->ptr == b->ptr;
 338     } else {
 339         return compareStringObjects(a,b) == 0;
 340     }
 341 }
 342
 343 size_t stringObjectLen(robj *o) {
 344     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 345     if (o->encoding == REDIS_ENCODING_RAW) {
 346         return sdslen(o->ptr);
 347     } else {
 348         char buf[32];
 349
 350         return ll2string(buf,32,(long)o->ptr);
 351     }
 352 }
 353
 354 int getDoubleFromObject(robj *o, double *target) {
 355     double value;
 356     char *eptr;
 357
 358     if (o == NULL) {
 359         value = 0;
 360     } else {
 361         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 362         if (o->encoding == REDIS_ENCODING_RAW) {
 363             errno = 0;
 364             value = strtod(o->ptr, &eptr);
 365             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 366                 errno == ERANGE || isnan(value))
 367                 return REDIS_ERR;
 368         } else if (o->encoding == REDIS_ENCODING_INT) {
 369             value = (long)o->ptr;
 370         } else {
 371             redisPanic("Unknown string encoding");
 372         }
 373     }
 374     *target = value;
 375     return REDIS_OK;
 376 }
 377
 378 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 379     double value;
 380     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 381         if (msg != NULL) {
 382             addReplyError(c,(char*)msg);
 383         } else {
 384             addReplyError(c,"value is not a valid float");
 385         }
 386         return REDIS_ERR;
 387     }
 388     *target = value;
 389     return REDIS_OK;
 390 }
 391
 392 int getLongDoubleFromObject(robj *o, long double *target) {
 393     long double value;
 394     char *eptr;
 395
 396     if (o == NULL) {
 397         value = 0;
 398     } else {
 399         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 400         if (o->encoding == REDIS_ENCODING_RAW) {
 401             errno = 0;
 402             value = strtold(o->ptr, &eptr);
 403             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 404                 errno == ERANGE || isnan(value))
 405                 return REDIS_ERR;
 406         } else if (o->encoding == REDIS_ENCODING_INT) {
 407             value = (long)o->ptr;
 408         } else {
 409             redisPanic("Unknown string encoding");
 410         }
 411     }
 412     *target = value;
 413     return REDIS_OK;
 414 }
 415
 416 int getLongDoubleFromObjectOrReply(redisClient *c, robj *o, long double *target, const char *msg) {
 417     long double value;
 418     if (getLongDoubleFromObject(o, &value) != REDIS_OK) {
 419         if (msg != NULL) {
 420             addReplyError(c,(char*)msg);
 421         } else {
 422             addReplyError(c,"value is not a valid float");
 423         }
 424         return REDIS_ERR;
 425     }
 426     *target = value;
 427     return REDIS_OK;
 428 }
 429
 430 int getLongLongFromObject(robj *o, long long *target) {
 431     long long value;
 432     char *eptr;
 433
 434     if (o == NULL) {
 435         value = 0;
 436     } else {
 437         redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
 438         if (o->encoding == REDIS_ENCODING_RAW) {
 439             errno = 0;
 440             value = strtoll(o->ptr, &eptr, 10);
 441             if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
 442                 errno == ERANGE)
 443                 return REDIS_ERR;
 444         } else if (o->encoding == REDIS_ENCODING_INT) {
 445             value = (long)o->ptr;
 446         } else {
 447             redisPanic("Unknown string encoding");
 448         }
 449     }
 450     if (target) *target = value;
 451     return REDIS_OK;
 452 }
 453
 454 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 455     long long value;
 456     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 457         if (msg != NULL) {
 458             addReplyError(c,(char*)msg);
 459         } else {
 460             addReplyError(c,"value is not an integer or out of range");
 461         }
 462         return REDIS_ERR;
 463     }
 464     *target = value;
 465     return REDIS_OK;
 466 }
 467
 468 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 469     long long value;
 470
 471     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 472     if (value < LONG_MIN || value > LONG_MAX) {
 473         if (msg != NULL) {
 474             addReplyError(c,(char*)msg);
 475         } else {
 476             addReplyError(c,"value is out of range");
 477         }
 478         return REDIS_ERR;
 479     }
 480     *target = value;
 481     return REDIS_OK;
 482 }
 483
 484 char *strEncoding(int encoding) {
 485     switch(encoding) {
 486     case REDIS_ENCODING_RAW: return "raw";
 487     case REDIS_ENCODING_INT: return "int";
 488     case REDIS_ENCODING_HT: return "hashtable";
 489     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 490     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 491     case REDIS_ENCODING_INTSET: return "intset";
 492     case REDIS_ENCODING_SKIPLIST: return "skiplist";
 493     default: return "unknown";
 494     }
 495 }
 496
 497 /* Given an object returns the min number of seconds the object was never
 498  * requested, using an approximated LRU algorithm. */
 499 unsigned long estimateObjectIdleTime(robj *o) {
 500     if (server.lruclock >= o->lru) {
 501         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 502     } else {
 503         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 504                     REDIS_LRU_CLOCK_RESOLUTION;
 505     }
 506 }
 507
 508 /* This is an helper function for the DEBUG command. We need to lookup keys
 509  * without any modification of LRU or other parameters. */
 510 robj *objectCommandLookup(redisClient *c, robj *key) {
 511     dictEntry *de;
 512
 513     if ((de = dictFind(c->db->dict,key->ptr)) == NULL) return NULL;
 514     return (robj*) dictGetVal(de);
 515 }
 516
 517 robj *objectCommandLookupOrReply(redisClient *c, robj *key, robj *reply) {
 518     robj *o = objectCommandLookup(c,key);
 519
 520     if (!o) addReply(c, reply);
 521     return o;
 522 }
 523
 524 /* Object command allows to inspect the internals of an Redis Object.
 525  * Usage: OBJECT <verb> ... arguments ... */
 526 void objectCommand(redisClient *c) {
 527     robj *o;
 528
 529     if (!strcasecmp(c->argv[1]->ptr,"refcount") && c->argc == 3) {
 530         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 531                 == NULL) return;
 532         addReplyLongLong(c,o->refcount);
 533     } else if (!strcasecmp(c->argv[1]->ptr,"encoding") && c->argc == 3) {
 534         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 535                 == NULL) return;
 536         addReplyBulkCString(c,strEncoding(o->encoding));
 537     } else if (!strcasecmp(c->argv[1]->ptr,"idletime") && c->argc == 3) {
 538         if ((o = objectCommandLookupOrReply(c,c->argv[2],shared.nullbulk))
 539                 == NULL) return;
 540         addReplyLongLong(c,estimateObjectIdleTime(o));
 541     } else {
 542         addReplyError(c,"Syntax error. Try OBJECT (refcount|encoding|idletime)");
 543     }
 544 }
 545