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