src/object.c

   1 #include "redis.h"
   2 #include <pthread.h>
   3 #include <math.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         !server.ds_enabled &&
  35         pthread_equal(pthread_self(),server.mainthread)) {
  36         incrRefCount(shared.integers[value]);
  37         o = shared.integers[value];
  38     } else {
  39         if (value >= LONG_MIN && value <= LONG_MAX) {
  40             o = createObject(REDIS_STRING, NULL);
  41             o->encoding = REDIS_ENCODING_INT;
  42             o->ptr = (void*)((long)value);
  43         } else {
  44             o = createObject(REDIS_STRING,sdsfromlonglong(value));
  45         }
  46     }
  47     return o;
  48 }
  49
  50 robj *dupStringObject(robj *o) {
  51     redisAssert(o->encoding == REDIS_ENCODING_RAW);
  52     return createStringObject(o->ptr,sdslen(o->ptr));
  53 }
  54
  55 robj *createListObject(void) {
  56     list *l = listCreate();
  57     robj *o = createObject(REDIS_LIST,l);
  58     listSetFreeMethod(l,decrRefCount);
  59     o->encoding = REDIS_ENCODING_LINKEDLIST;
  60     return o;
  61 }
  62
  63 robj *createZiplistObject(void) {
  64     unsigned char *zl = ziplistNew();
  65     robj *o = createObject(REDIS_LIST,zl);
  66     o->encoding = REDIS_ENCODING_ZIPLIST;
  67     return o;
  68 }
  69
  70 robj *createSetObject(void) {
  71     dict *d = dictCreate(&setDictType,NULL);
  72     robj *o = createObject(REDIS_SET,d);
  73     o->encoding = REDIS_ENCODING_HT;
  74     return o;
  75 }
  76
  77 robj *createIntsetObject(void) {
  78     intset *is = intsetNew();
  79     robj *o = createObject(REDIS_SET,is);
  80     o->encoding = REDIS_ENCODING_INTSET;
  81     return o;
  82 }
  83
  84 robj *createHashObject(void) {
  85     /* All the Hashes start as zipmaps. Will be automatically converted
  86      * into hash tables if there are enough elements or big elements
  87      * inside. */
  88     unsigned char *zm = zipmapNew();
  89     robj *o = createObject(REDIS_HASH,zm);
  90     o->encoding = REDIS_ENCODING_ZIPMAP;
  91     return o;
  92 }
  93
  94 robj *createZsetObject(void) {
  95     zset *zs = zmalloc(sizeof(*zs));
  96     zs->dict = dictCreate(&zsetDictType,NULL);
  97     zs->zsl = zslCreate();
  98     return createObject(REDIS_ZSET,zs);
  99 }
 100
 101 robj *createZsetZiplistObject(void) {
 102     unsigned char *zl = ziplistNew();
 103     robj *o = createObject(REDIS_ZSET,zl);
 104     o->encoding = REDIS_ENCODING_ZIPLIST;
 105     return o;
 106 }
 107
 108 void freeStringObject(robj *o) {
 109     if (o->encoding == REDIS_ENCODING_RAW) {
 110         sdsfree(o->ptr);
 111     }
 112 }
 113
 114 void freeListObject(robj *o) {
 115     switch (o->encoding) {
 116     case REDIS_ENCODING_LINKEDLIST:
 117         listRelease((list*) o->ptr);
 118         break;
 119     case REDIS_ENCODING_ZIPLIST:
 120         zfree(o->ptr);
 121         break;
 122     default:
 123         redisPanic("Unknown list encoding type");
 124     }
 125 }
 126
 127 void freeSetObject(robj *o) {
 128     switch (o->encoding) {
 129     case REDIS_ENCODING_HT:
 130         dictRelease((dict*) o->ptr);
 131         break;
 132     case REDIS_ENCODING_INTSET:
 133         zfree(o->ptr);
 134         break;
 135     default:
 136         redisPanic("Unknown set encoding type");
 137     }
 138 }
 139
 140 void freeZsetObject(robj *o) {
 141     zset *zs = o->ptr;
 142
 143     dictRelease(zs->dict);
 144     zslFree(zs->zsl);
 145     zfree(zs);
 146 }
 147
 148 void freeHashObject(robj *o) {
 149     switch (o->encoding) {
 150     case REDIS_ENCODING_HT:
 151         dictRelease((dict*) o->ptr);
 152         break;
 153     case REDIS_ENCODING_ZIPMAP:
 154         zfree(o->ptr);
 155         break;
 156     default:
 157         redisPanic("Unknown hash encoding type");
 158         break;
 159     }
 160 }
 161
 162 void incrRefCount(robj *o) {
 163     o->refcount++;
 164 }
 165
 166 void decrRefCount(void *obj) {
 167     robj *o = obj;
 168
 169     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 170     if (--(o->refcount) == 0) {
 171         switch(o->type) {
 172         case REDIS_STRING: freeStringObject(o); break;
 173         case REDIS_LIST: freeListObject(o); break;
 174         case REDIS_SET: freeSetObject(o); break;
 175         case REDIS_ZSET: freeZsetObject(o); break;
 176         case REDIS_HASH: freeHashObject(o); break;
 177         default: redisPanic("Unknown object type"); break;
 178         }
 179         o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
 180         zfree(o);
 181     }
 182 }
 183
 184 int checkType(redisClient *c, robj *o, int type) {
 185     if (o->type != type) {
 186         addReply(c,shared.wrongtypeerr);
 187         return 1;
 188     }
 189     return 0;
 190 }
 191
 192 /* Try to encode a string object in order to save space */
 193 robj *tryObjectEncoding(robj *o) {
 194     long value;
 195     sds s = o->ptr;
 196
 197     if (o->encoding != REDIS_ENCODING_RAW)
 198         return o; /* Already encoded */
 199
 200     /* It's not safe to encode shared objects: shared objects can be shared
 201      * everywhere in the "object space" of Redis. Encoded objects can only
 202      * appear as "values" (and not, for instance, as keys) */
 203      if (o->refcount > 1) return o;
 204
 205     /* Currently we try to encode only strings */
 206     redisAssert(o->type == REDIS_STRING);
 207
 208     /* Check if we can represent this string as a long integer */
 209     if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
 210
 211     /* Ok, this object can be encoded...
 212      *
 213      * Can I use a shared object? Only if the object is inside a given
 214      * range and if the back end in use is in-memory. For disk store every
 215      * object in memory used as value should be independent.
 216      *
 217      * Note that we also avoid using shared integers when maxmemory is used
 218      * because every object needs to have a private LRU field for the LRU
 219      * algorithm to work well. */
 220     if (!server.ds_enabled &&
 221         server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
 222         pthread_equal(pthread_self(),server.mainthread))
 223     {
 224         decrRefCount(o);
 225         incrRefCount(shared.integers[value]);
 226         return shared.integers[value];
 227     } else {
 228         o->encoding = REDIS_ENCODING_INT;
 229         sdsfree(o->ptr);
 230         o->ptr = (void*) value;
 231         return o;
 232     }
 233 }
 234
 235 /* Get a decoded version of an encoded object (returned as a new object).
 236  * If the object is already raw-encoded just increment the ref count. */
 237 robj *getDecodedObject(robj *o) {
 238     robj *dec;
 239
 240     if (o->encoding == REDIS_ENCODING_RAW) {
 241         incrRefCount(o);
 242         return o;
 243     }
 244     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 245         char buf[32];
 246
 247         ll2string(buf,32,(long)o->ptr);
 248         dec = createStringObject(buf,strlen(buf));
 249         return dec;
 250     } else {
 251         redisPanic("Unknown encoding type");
 252     }
 253 }
 254
 255 /* Compare two string objects via strcmp() or alike.
 256  * Note that the objects may be integer-encoded. In such a case we
 257  * use ll2string() to get a string representation of the numbers on the stack
 258  * and compare the strings, it's much faster than calling getDecodedObject().
 259  *
 260  * Important note: if objects are not integer encoded, but binary-safe strings,
 261  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 262  * binary safe. */
 263 int compareStringObjects(robj *a, robj *b) {
 264     redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
 265     char bufa[128], bufb[128], *astr, *bstr;
 266     int bothsds = 1;
 267
 268     if (a == b) return 0;
 269     if (a->encoding != REDIS_ENCODING_RAW) {
 270         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 271         astr = bufa;
 272         bothsds = 0;
 273     } else {
 274         astr = a->ptr;
 275     }
 276     if (b->encoding != REDIS_ENCODING_RAW) {
 277         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 278         bstr = bufb;
 279         bothsds = 0;
 280     } else {
 281         bstr = b->ptr;
 282     }
 283     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 284 }
 285
 286 /* Equal string objects return 1 if the two objects are the same from the
 287  * point of view of a string comparison, otherwise 0 is returned. Note that
 288  * this function is faster then checking for (compareStringObject(a,b) == 0)
 289  * because it can perform some more optimization. */
 290 int equalStringObjects(robj *a, robj *b) {
 291     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 292         return a->ptr == b->ptr;
 293     } else {
 294         return compareStringObjects(a,b) == 0;
 295     }
 296 }
 297
 298 size_t stringObjectLen(robj *o) {
 299     redisAssert(o->type == REDIS_STRING);
 300     if (o->encoding == REDIS_ENCODING_RAW) {
 301         return sdslen(o->ptr);
 302     } else {
 303         char buf[32];
 304
 305         return ll2string(buf,32,(long)o->ptr);
 306     }
 307 }
 308
 309 int getDoubleFromObject(robj *o, double *target) {
 310     double value;
 311     char *eptr;
 312
 313     if (o == NULL) {
 314         value = 0;
 315     } else {
 316         redisAssert(o->type == REDIS_STRING);
 317         if (o->encoding == REDIS_ENCODING_RAW) {
 318             value = strtod(o->ptr, &eptr);
 319             if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
 320         } else if (o->encoding == REDIS_ENCODING_INT) {
 321             value = (long)o->ptr;
 322         } else {
 323             redisPanic("Unknown string encoding");
 324         }
 325     }
 326
 327     *target = value;
 328     return REDIS_OK;
 329 }
 330
 331 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 332     double value;
 333     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 334         if (msg != NULL) {
 335             addReplyError(c,(char*)msg);
 336         } else {
 337             addReplyError(c,"value is not a double");
 338         }
 339         return REDIS_ERR;
 340     }
 341
 342     *target = value;
 343     return REDIS_OK;
 344 }
 345
 346 int getLongLongFromObject(robj *o, long long *target) {
 347     long long value;
 348     char *eptr;
 349
 350     if (o == NULL) {
 351         value = 0;
 352     } else {
 353         redisAssert(o->type == REDIS_STRING);
 354         if (o->encoding == REDIS_ENCODING_RAW) {
 355             value = strtoll(o->ptr, &eptr, 10);
 356             if (eptr[0] != '\0') return REDIS_ERR;
 357             if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
 358                 return REDIS_ERR;
 359         } else if (o->encoding == REDIS_ENCODING_INT) {
 360             value = (long)o->ptr;
 361         } else {
 362             redisPanic("Unknown string encoding");
 363         }
 364     }
 365
 366     if (target) *target = value;
 367     return REDIS_OK;
 368 }
 369
 370 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 371     long long value;
 372     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 373         if (msg != NULL) {
 374             addReplyError(c,(char*)msg);
 375         } else {
 376             addReplyError(c,"value is not an integer or out of range");
 377         }
 378         return REDIS_ERR;
 379     }
 380
 381     *target = value;
 382     return REDIS_OK;
 383 }
 384
 385 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 386     long long value;
 387
 388     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 389     if (value < LONG_MIN || value > LONG_MAX) {
 390         if (msg != NULL) {
 391             addReplyError(c,(char*)msg);
 392         } else {
 393             addReplyError(c,"value is out of range");
 394         }
 395         return REDIS_ERR;
 396     }
 397
 398     *target = value;
 399     return REDIS_OK;
 400 }
 401
 402 char *strEncoding(int encoding) {
 403     switch(encoding) {
 404     case REDIS_ENCODING_RAW: return "raw";
 405     case REDIS_ENCODING_INT: return "int";
 406     case REDIS_ENCODING_HT: return "hashtable";
 407     case REDIS_ENCODING_ZIPMAP: return "zipmap";
 408     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 409     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 410     case REDIS_ENCODING_INTSET: return "intset";
 411     default: return "unknown";
 412     }
 413 }
 414
 415 /* Given an object returns the min number of seconds the object was never
 416  * requested, using an approximated LRU algorithm. */
 417 unsigned long estimateObjectIdleTime(robj *o) {
 418     if (server.lruclock >= o->lru) {
 419         return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
 420     } else {
 421         return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
 422                     REDIS_LRU_CLOCK_RESOLUTION;
 423     }
 424 }