src/object.c

#include "redis.h"
#include <pthread.h>
#include <math.h>

robj *createObject(int type, void *ptr) {
    robj *o = zmalloc(sizeof(*o));
    o->type = type;
    o->encoding = REDIS_ENCODING_RAW;
    o->ptr = ptr;
    o->refcount = 1;

    /* Set the LRU to the current lruclock (minutes resolution).
     * We do this regardless of the fact VM is active as LRU is also
     * used for the maxmemory directive when Redis is used as cache.
     *
     * Note that this code may run in the context of an I/O thread
     * and accessing server.lruclock in theory is an error
     * (no locks). But in practice this is safe, and even if we read
     * garbage Redis will not fail. */
    o->lru = server.lruclock;
    /* The following is only needed if VM is active, but since the conditional
     * is probably more costly than initializing the field it's better to
     * have every field properly initialized anyway. */
    return o;
}

robj *createStringObject(char *ptr, size_t len) {
    return createObject(REDIS_STRING,sdsnewlen(ptr,len));
}

robj *createStringObjectFromLongLong(long long value) {
    robj *o;
    if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
        !server.ds_enabled &&
        pthread_equal(pthread_self(),server.mainthread)) {
        incrRefCount(shared.integers[value]);
        o = shared.integers[value];
    } else {
        if (value >= LONG_MIN && value <= LONG_MAX) {
            o = createObject(REDIS_STRING, NULL);
            o->encoding = REDIS_ENCODING_INT;
            o->ptr = (void*)((long)value);
        } else {
            o = createObject(REDIS_STRING,sdsfromlonglong(value));
        }
    }
    return o;
}

robj *dupStringObject(robj *o) {
    redisAssert(o->encoding == REDIS_ENCODING_RAW);
    return createStringObject(o->ptr,sdslen(o->ptr));
}

robj *createListObject(void) {
    list *l = listCreate();
    robj *o = createObject(REDIS_LIST,l);
    listSetFreeMethod(l,decrRefCount);
    o->encoding = REDIS_ENCODING_LINKEDLIST;
    return o;
}

robj *createZiplistObject(void) {
    unsigned char *zl = ziplistNew();
    robj *o = createObject(REDIS_LIST,zl);
    o->encoding = REDIS_ENCODING_ZIPLIST;
    return o;
}

robj *createSetObject(void) {
    dict *d = dictCreate(&setDictType,NULL);
    robj *o = createObject(REDIS_SET,d);
    o->encoding = REDIS_ENCODING_HT;
    return o;
}

robj *createIntsetObject(void) {
    intset *is = intsetNew();
    robj *o = createObject(REDIS_SET,is);
    o->encoding = REDIS_ENCODING_INTSET;
    return o;
}

robj *createHashObject(void) {
    /* All the Hashes start as zipmaps. Will be automatically converted
     * into hash tables if there are enough elements or big elements
     * inside. */
    unsigned char *zm = zipmapNew();
    robj *o = createObject(REDIS_HASH,zm);
    o->encoding = REDIS_ENCODING_ZIPMAP;
    return o;
}

robj *createZsetObject(void) {
    zset *zs = zmalloc(sizeof(*zs));
    robj *o;

    zs->dict = dictCreate(&zsetDictType,NULL);
    zs->zsl = zslCreate();
    o = createObject(REDIS_ZSET,zs);
    o->encoding = REDIS_ENCODING_SKIPLIST;
    return o;
}

robj *createZsetZiplistObject(void) {
    unsigned char *zl = ziplistNew();
    robj *o = createObject(REDIS_ZSET,zl);
    o->encoding = REDIS_ENCODING_ZIPLIST;
    return o;
}

void freeStringObject(robj *o) {
    if (o->encoding == REDIS_ENCODING_RAW) {
        sdsfree(o->ptr);
    }
}

void freeListObject(robj *o) {
    switch (o->encoding) {
    case REDIS_ENCODING_LINKEDLIST:
        listRelease((list*) o->ptr);
        break;
    case REDIS_ENCODING_ZIPLIST:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown list encoding type");
    }
}

void freeSetObject(robj *o) {
    switch (o->encoding) {
    case REDIS_ENCODING_HT:
        dictRelease((dict*) o->ptr);
        break;
    case REDIS_ENCODING_INTSET:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown set encoding type");
    }
}

void freeZsetObject(robj *o) {
    zset *zs;
    switch (o->encoding) {
    case REDIS_ENCODING_SKIPLIST:
        zs = o->ptr;
        dictRelease(zs->dict);
        zslFree(zs->zsl);
        zfree(zs);
        break;
    case REDIS_ENCODING_ZIPLIST:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown sorted set encoding");
    }
}

void freeHashObject(robj *o) {
    switch (o->encoding) {
    case REDIS_ENCODING_HT:
        dictRelease((dict*) o->ptr);
        break;
    case REDIS_ENCODING_ZIPMAP:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown hash encoding type");
        break;
    }
}

void incrRefCount(robj *o) {
    o->refcount++;
}

void decrRefCount(void *obj) {
    robj *o = obj;

    if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
    if (o->refcount == 1) {
        switch(o->type) {
        case REDIS_STRING: freeStringObject(o); break;
        case REDIS_LIST: freeListObject(o); break;
        case REDIS_SET: freeSetObject(o); break;
        case REDIS_ZSET: freeZsetObject(o); break;
        case REDIS_HASH: freeHashObject(o); break;
        default: redisPanic("Unknown object type"); break;
        }
        zfree(o);
    } else {
        o->refcount--;
    }
}

int checkType(redisClient *c, robj *o, int type) {
    if (o->type != type) {
        addReply(c,shared.wrongtypeerr);
        return 1;
    }
    return 0;
}

int isObjectRepresentableAsLongLong(robj *o, long long *llval) {
    redisAssert(o->type == REDIS_STRING);
    if (o->encoding == REDIS_ENCODING_INT) {
        if (llval) *llval = (long) o->ptr;
        return REDIS_OK;
    } else {
        return string2ll(o->ptr,sdslen(o->ptr),llval) ? REDIS_OK : REDIS_ERR;
    }
}

/* Try to encode a string object in order to save space */
robj *tryObjectEncoding(robj *o) {
    long value;
    sds s = o->ptr;

    if (o->encoding != REDIS_ENCODING_RAW)
        return o; /* Already encoded */

    /* It's not safe to encode shared objects: shared objects can be shared
     * everywhere in the "object space" of Redis. Encoded objects can only
     * appear as "values" (and not, for instance, as keys) */
     if (o->refcount > 1) return o;

    /* Currently we try to encode only strings */
    redisAssert(o->type == REDIS_STRING);

    /* Check if we can represent this string as a long integer */
    if (!string2l(s,sdslen(s),&value)) return o;

    /* Ok, this object can be encoded...
     *
     * Can I use a shared object? Only if the object is inside a given
     * range and if the back end in use is in-memory. For disk store every
     * object in memory used as value should be independent.
     *
     * Note that we also avoid using shared integers when maxmemory is used
     * because every object needs to have a private LRU field for the LRU
     * algorithm to work well. */
    if (!server.ds_enabled &&
        server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
        pthread_equal(pthread_self(),server.mainthread))
    {
        decrRefCount(o);
        incrRefCount(shared.integers[value]);
        return shared.integers[value];
    } else {
        o->encoding = REDIS_ENCODING_INT;
        sdsfree(o->ptr);
        o->ptr = (void*) value;
        return o;
    }
}

/* Get a decoded version of an encoded object (returned as a new object).
 * If the object is already raw-encoded just increment the ref count. */
robj *getDecodedObject(robj *o) {
    robj *dec;

    if (o->encoding == REDIS_ENCODING_RAW) {
        incrRefCount(o);
        return o;
    }
    if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
        char buf[32];

        ll2string(buf,32,(long)o->ptr);
        dec = createStringObject(buf,strlen(buf));
        return dec;
    } else {
        redisPanic("Unknown encoding type");
    }
}

/* Compare two string objects via strcmp() or alike.
 * Note that the objects may be integer-encoded. In such a case we
 * use ll2string() to get a string representation of the numbers on the stack
 * and compare the strings, it's much faster than calling getDecodedObject().
 *
 * Important note: if objects are not integer encoded, but binary-safe strings,
 * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 * binary safe. */
int compareStringObjects(robj *a, robj *b) {
    redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
    char bufa[128], bufb[128], *astr, *bstr;
    int bothsds = 1;

    if (a == b) return 0;
    if (a->encoding != REDIS_ENCODING_RAW) {
        ll2string(bufa,sizeof(bufa),(long) a->ptr);
        astr = bufa;
        bothsds = 0;
    } else {
        astr = a->ptr;
    }
    if (b->encoding != REDIS_ENCODING_RAW) {
        ll2string(bufb,sizeof(bufb),(long) b->ptr);
        bstr = bufb;
        bothsds = 0;
    } else {
        bstr = b->ptr;
    }
    return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
}

/* Equal string objects return 1 if the two objects are the same from the
 * point of view of a string comparison, otherwise 0 is returned. Note that
 * this function is faster then checking for (compareStringObject(a,b) == 0)
 * because it can perform some more optimization. */
int equalStringObjects(robj *a, robj *b) {
    if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
        return a->ptr == b->ptr;
    } else {
        return compareStringObjects(a,b) == 0;
    }
}

size_t stringObjectLen(robj *o) {
    redisAssert(o->type == REDIS_STRING);
    if (o->encoding == REDIS_ENCODING_RAW) {
        return sdslen(o->ptr);
    } else {
        char buf[32];

        return ll2string(buf,32,(long)o->ptr);
    }
}

int getDoubleFromObject(robj *o, double *target) {
    double value;
    char *eptr;

    if (o == NULL) {
        value = 0;
    } else {
        redisAssert(o->type == REDIS_STRING);
        if (o->encoding == REDIS_ENCODING_RAW) {
            value = strtod(o->ptr, &eptr);
            if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
        } else if (o->encoding == REDIS_ENCODING_INT) {
            value = (long)o->ptr;
        } else {
            redisPanic("Unknown string encoding");
        }
    }

    *target = value;
    return REDIS_OK;
}

int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
    double value;
    if (getDoubleFromObject(o, &value) != REDIS_OK) {
        if (msg != NULL) {
            addReplyError(c,(char*)msg);
        } else {
            addReplyError(c,"value is not a double");
        }
        return REDIS_ERR;
    }

    *target = value;
    return REDIS_OK;
}

int getLongLongFromObject(robj *o, long long *target) {
    long long value;
    char *eptr;

    if (o == NULL) {
        value = 0;
    } else {
        redisAssert(o->type == REDIS_STRING);
        if (o->encoding == REDIS_ENCODING_RAW) {
            value = strtoll(o->ptr, &eptr, 10);
            if (eptr[0] != '\0') return REDIS_ERR;
            if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
                return REDIS_ERR;
        } else if (o->encoding == REDIS_ENCODING_INT) {
            value = (long)o->ptr;
        } else {
            redisPanic("Unknown string encoding");
        }
    }

    if (target) *target = value;
    return REDIS_OK;
}

int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
    long long value;
    if (getLongLongFromObject(o, &value) != REDIS_OK) {
        if (msg != NULL) {
            addReplyError(c,(char*)msg);
        } else {
            addReplyError(c,"value is not an integer or out of range");
        }
        return REDIS_ERR;
    }

    *target = value;
    return REDIS_OK;
}

int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
    long long value;

    if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
    if (value < LONG_MIN || value > LONG_MAX) {
        if (msg != NULL) {
            addReplyError(c,(char*)msg);
        } else {
            addReplyError(c,"value is out of range");
        }
        return REDIS_ERR;
    }

    *target = value;
    return REDIS_OK;
}

char *strEncoding(int encoding) {
    switch(encoding) {
    case REDIS_ENCODING_RAW: return "raw";
    case REDIS_ENCODING_INT: return "int";
    case REDIS_ENCODING_HT: return "hashtable";
    case REDIS_ENCODING_ZIPMAP: return "zipmap";
    case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
    case REDIS_ENCODING_ZIPLIST: return "ziplist";
    case REDIS_ENCODING_INTSET: return "intset";
    case REDIS_ENCODING_SKIPLIST: return "skiplist";
    default: return "unknown";
    }
}

/* Given an object returns the min number of seconds the object was never
 * requested, using an approximated LRU algorithm. */
unsigned long estimateObjectIdleTime(robj *o) {
    if (server.lruclock >= o->lru) {
        return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
    } else {
        return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
                    REDIS_LRU_CLOCK_RESOLUTION;
    }
}

/* This is an helper function for the DEBUG command. We need to lookup keys
 * without any modification of LRU or other parameters. */
robj *objectCommandLookup(redisClient *c, robj *key) {
    dictEntry *de;

    if ((de = dictFind(c->db->dict,key->ptr)) == NULL) return NULL;
    return (robj*) dictGetEntryVal(de);
}

robj *objectCommandLookupOrReply(redisClient *c, robj *key, robj *reply) {
    robj *o = objectCommandLookup(c,key);

    if (!o) addReply(c, reply);
    return o;
}

/* Object command allows to inspect the internals of an Redis Object.
 * Usage: OBJECT <verb> ... arguments ... */
void objectCommand(redisClient *c) {
    robj *o;

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