brainstorming with myself in dscache.c comments

[redis.git] / src / t_string.c

#include <limits.h>
#include "redis.h"

/*-----------------------------------------------------------------------------
 * String Commands
 *----------------------------------------------------------------------------*/

static int checkStringLength(redisClient *c, long long size) {
    if (size > 512*1024*1024) {
        addReplyError(c,"string exceeds maximum allowed size (512MB)");
        return REDIS_ERR;
    }
    return REDIS_OK;
}

void setGenericCommand(redisClient *c, int nx, robj *key, robj *val, robj *expire) {
    int retval;
    long seconds = 0; /* initialized to avoid an harmness warning */

    if (expire) {
        if (getLongFromObjectOrReply(c, expire, &seconds, NULL) != REDIS_OK)
            return;
        if (seconds <= 0) {
            addReplyError(c,"invalid expire time in SETEX");
            return;
        }
    }

    retval = dbAdd(c->db,key,val);
    if (retval == REDIS_ERR) {
        if (!nx) {
            dbReplace(c->db,key,val);
            incrRefCount(val);
        } else {
            addReply(c,shared.czero);
            return;
        }
    } else {
        incrRefCount(val);
    }
    signalModifiedKey(c->db,key);
    server.dirty++;
    removeExpire(c->db,key);
    if (expire) setExpire(c->db,key,time(NULL)+seconds);
    addReply(c, nx ? shared.cone : shared.ok);
}

void setCommand(redisClient *c) {
    c->argv[2] = tryObjectEncoding(c->argv[2]);
    setGenericCommand(c,0,c->argv[1],c->argv[2],NULL);
}

void setnxCommand(redisClient *c) {
    c->argv[2] = tryObjectEncoding(c->argv[2]);
    setGenericCommand(c,1,c->argv[1],c->argv[2],NULL);
}

void setexCommand(redisClient *c) {
    c->argv[3] = tryObjectEncoding(c->argv[3]);
    setGenericCommand(c,0,c->argv[1],c->argv[3],c->argv[2]);
}

int getGenericCommand(redisClient *c) {
    robj *o;

    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL)
        return REDIS_OK;

    if (o->type != REDIS_STRING) {
        addReply(c,shared.wrongtypeerr);
        return REDIS_ERR;
    } else {
        addReplyBulk(c,o);
        return REDIS_OK;
    }
}

void getCommand(redisClient *c) {
    getGenericCommand(c);
}

void getsetCommand(redisClient *c) {
    if (getGenericCommand(c) == REDIS_ERR) return;
    c->argv[2] = tryObjectEncoding(c->argv[2]);
    dbReplace(c->db,c->argv[1],c->argv[2]);
    incrRefCount(c->argv[2]);
    signalModifiedKey(c->db,c->argv[1]);
    server.dirty++;
    removeExpire(c->db,c->argv[1]);
}

static int getBitOffsetFromArgument(redisClient *c, robj *o, size_t *offset) {
    long long loffset;
    char *err = "bit offset is not an integer or out of range";

    if (getLongLongFromObjectOrReply(c,o,&loffset,err) != REDIS_OK)
        return REDIS_ERR;

    /* Limit offset to 512MB in bytes */
    if ((loffset < 0) || ((unsigned long long)loffset >> 3) >= (512*1024*1024))
    {
        addReplyError(c,err);
        return REDIS_ERR;
    }

    *offset = (size_t)loffset;
    return REDIS_OK;
}

void setbitCommand(redisClient *c) {
    robj *o;
    char *err = "bit is not an integer or out of range";
    size_t bitoffset;
    int byte, bit;
    int byteval, bitval;
    long on;

    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset) != REDIS_OK)
        return;

    if (getLongFromObjectOrReply(c,c->argv[3],&on,err) != REDIS_OK)
        return;

    /* Bits can only be set or cleared... */
    if (on & ~1) {
        addReplyError(c,err);
        return;
    }

    o = lookupKeyWrite(c->db,c->argv[1]);
    if (o == NULL) {
        o = createObject(REDIS_STRING,sdsempty());
        dbAdd(c->db,c->argv[1],o);
    } else {
        if (checkType(c,o,REDIS_STRING)) return;

        /* Create a copy when the object is shared or encoded. */
        if (o->refcount != 1 || o->encoding != REDIS_ENCODING_RAW) {
            robj *decoded = getDecodedObject(o);
            o = createStringObject(decoded->ptr, sdslen(decoded->ptr));
            decrRefCount(decoded);
            dbReplace(c->db,c->argv[1],o);
        }
    }

    /* Grow sds value to the right length if necessary */
    byte = bitoffset >> 3;
    o->ptr = sdsgrowzero(o->ptr,byte+1);

    /* Get current values */
    byteval = ((char*)o->ptr)[byte];
    bit = 7 - (bitoffset & 0x7);
    bitval = byteval & (1 << bit);

    /* Update byte with new bit value and return original value */
    byteval &= ~(1 << bit);
    byteval |= ((on & 0x1) << bit);
    ((char*)o->ptr)[byte] = byteval;
    signalModifiedKey(c->db,c->argv[1]);
    server.dirty++;
    addReply(c, bitval ? shared.cone : shared.czero);
}

void getbitCommand(redisClient *c) {
    robj *o;
    char llbuf[32];
    size_t bitoffset;
    size_t byte, bit;
    size_t bitval = 0;

    if (getBitOffsetFromArgument(c,c->argv[2],&bitoffset) != REDIS_OK)
        return;

    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
        checkType(c,o,REDIS_STRING)) return;

    byte = bitoffset >> 3;
    bit = 7 - (bitoffset & 0x7);
    if (o->encoding != REDIS_ENCODING_RAW) {
        if (byte < (size_t)ll2string(llbuf,sizeof(llbuf),(long)o->ptr))
            bitval = llbuf[byte] & (1 << bit);
    } else {
        if (byte < sdslen(o->ptr))
            bitval = ((char*)o->ptr)[byte] & (1 << bit);
    }

    addReply(c, bitval ? shared.cone : shared.czero);
}

void setrangeCommand(redisClient *c) {
    robj *o;
    long offset;
    sds value = c->argv[3]->ptr;

    if (getLongFromObjectOrReply(c,c->argv[2],&offset,NULL) != REDIS_OK)
        return;

    if (offset < 0) {
        addReplyError(c,"offset is out of range");
        return;
    }

    o = lookupKeyWrite(c->db,c->argv[1]);
    if (o == NULL) {
        /* Return 0 when setting nothing on a non-existing string */
        if (sdslen(value) == 0) {
            addReply(c,shared.czero);
            return;
        }

        /* Return when the resulting string exceeds allowed size */
        if (checkStringLength(c,offset+sdslen(value)) != REDIS_OK)
            return;

        o = createObject(REDIS_STRING,sdsempty());
        dbAdd(c->db,c->argv[1],o);
    } else {
        size_t olen;

        /* Key exists, check type */
        if (checkType(c,o,REDIS_STRING))
            return;

        /* Return existing string length when setting nothing */
        olen = stringObjectLen(o);
        if (sdslen(value) == 0) {
            addReplyLongLong(c,olen);
            return;
        }

        /* Return when the resulting string exceeds allowed size */
        if (checkStringLength(c,offset+sdslen(value)) != REDIS_OK)
            return;

        /* Create a copy when the object is shared or encoded. */
        if (o->refcount != 1 || o->encoding != REDIS_ENCODING_RAW) {
            robj *decoded = getDecodedObject(o);
            o = createStringObject(decoded->ptr, sdslen(decoded->ptr));
            decrRefCount(decoded);
            dbReplace(c->db,c->argv[1],o);
        }
    }

    if (sdslen(value) > 0) {
        o->ptr = sdsgrowzero(o->ptr,offset+sdslen(value));
        memcpy((char*)o->ptr+offset,value,sdslen(value));
        signalModifiedKey(c->db,c->argv[1]);
        server.dirty++;
    }
    addReplyLongLong(c,sdslen(o->ptr));
}

void getrangeCommand(redisClient *c) {
    robj *o;
    long start, end;
    char *str, llbuf[32];
    size_t strlen;

    if (getLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK)
        return;
    if (getLongFromObjectOrReply(c,c->argv[3],&end,NULL) != REDIS_OK)
        return;
    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
        checkType(c,o,REDIS_STRING)) return;

    if (o->encoding == REDIS_ENCODING_INT) {
        str = llbuf;
        strlen = ll2string(llbuf,sizeof(llbuf),(long)o->ptr);
    } else {
        str = o->ptr;
        strlen = sdslen(str);
    }

    /* Convert negative indexes */
    if (start < 0) start = strlen+start;
    if (end < 0) end = strlen+end;
    if (start < 0) start = 0;
    if (end < 0) end = 0;
    if ((unsigned)end >= strlen) end = strlen-1;

    /* Precondition: end >= 0 && end < strlen, so the only condition where
     * nothing can be returned is: start > end. */
    if (start > end) {
        addReply(c,shared.nullbulk);
    } else {
        addReplyBulkCBuffer(c,(char*)str+start,end-start+1);
    }
}

void mgetCommand(redisClient *c) {
    int j;

    addReplyMultiBulkLen(c,c->argc-1);
    for (j = 1; j < c->argc; j++) {
        robj *o = lookupKeyRead(c->db,c->argv[j]);
        if (o == NULL) {
            addReply(c,shared.nullbulk);
        } else {
            if (o->type != REDIS_STRING) {
                addReply(c,shared.nullbulk);
            } else {
                addReplyBulk(c,o);
            }
        }
    }
}

void msetGenericCommand(redisClient *c, int nx) {
    int j, busykeys = 0;

    if ((c->argc % 2) == 0) {
        addReplyError(c,"wrong number of arguments for MSET");
        return;
    }
    /* Handle the NX flag. The MSETNX semantic is to return zero and don't
     * set nothing at all if at least one already key exists. */
    if (nx) {
        for (j = 1; j < c->argc; j += 2) {
            if (lookupKeyWrite(c->db,c->argv[j]) != NULL) {
                busykeys++;
            }
        }
    }
    if (busykeys) {
        addReply(c, shared.czero);
        return;
    }

    for (j = 1; j < c->argc; j += 2) {
        c->argv[j+1] = tryObjectEncoding(c->argv[j+1]);
        dbReplace(c->db,c->argv[j],c->argv[j+1]);
        incrRefCount(c->argv[j+1]);
        removeExpire(c->db,c->argv[j]);
        signalModifiedKey(c->db,c->argv[j]);
    }
    server.dirty += (c->argc-1)/2;
    addReply(c, nx ? shared.cone : shared.ok);
}

void msetCommand(redisClient *c) {
    msetGenericCommand(c,0);
}

void msetnxCommand(redisClient *c) {
    msetGenericCommand(c,1);
}

void incrDecrCommand(redisClient *c, long long incr) {
    long long value, oldvalue;
    robj *o;

    o = lookupKeyWrite(c->db,c->argv[1]);
    if (o != NULL && checkType(c,o,REDIS_STRING)) return;
    if (getLongLongFromObjectOrReply(c,o,&value,NULL) != REDIS_OK) return;

    oldvalue = value;
    value += incr;
    if ((incr < 0 && value > oldvalue) || (incr > 0 && value < oldvalue)) {
        addReplyError(c,"increment or decrement would overflow");
        return;
    }
    o = createStringObjectFromLongLong(value);
    dbReplace(c->db,c->argv[1],o);
    signalModifiedKey(c->db,c->argv[1]);
    server.dirty++;
    addReply(c,shared.colon);
    addReply(c,o);
    addReply(c,shared.crlf);
}

void incrCommand(redisClient *c) {
    incrDecrCommand(c,1);
}

void decrCommand(redisClient *c) {
    incrDecrCommand(c,-1);
}

void incrbyCommand(redisClient *c) {
    long long incr;

    if (getLongLongFromObjectOrReply(c, c->argv[2], &incr, NULL) != REDIS_OK) return;
    incrDecrCommand(c,incr);
}

void decrbyCommand(redisClient *c) {
    long long incr;

    if (getLongLongFromObjectOrReply(c, c->argv[2], &incr, NULL) != REDIS_OK) return;
    incrDecrCommand(c,-incr);
}

void appendCommand(redisClient *c) {
    size_t totlen;
    robj *o, *append;

    o = lookupKeyWrite(c->db,c->argv[1]);
    if (o == NULL) {
        /* Create the key */
        c->argv[2] = tryObjectEncoding(c->argv[2]);
        dbAdd(c->db,c->argv[1],c->argv[2]);
        incrRefCount(c->argv[2]);
        totlen = stringObjectLen(c->argv[2]);
    } else {
        /* Key exists, check type */
        if (checkType(c,o,REDIS_STRING))
            return;

        /* "append" is an argument, so always an sds */
        append = c->argv[2];
        totlen = stringObjectLen(o)+sdslen(append->ptr);
        if (checkStringLength(c,totlen) != REDIS_OK)
            return;

        /* If the object is shared or encoded, we have to make a copy */
        if (o->refcount != 1 || o->encoding != REDIS_ENCODING_RAW) {
            robj *decoded = getDecodedObject(o);
            o = createStringObject(decoded->ptr, sdslen(decoded->ptr));
            decrRefCount(decoded);
            dbReplace(c->db,c->argv[1],o);
        }

        /* Append the value */
        o->ptr = sdscatlen(o->ptr,append->ptr,sdslen(append->ptr));
        totlen = sdslen(o->ptr);
    }
    signalModifiedKey(c->db,c->argv[1]);
    server.dirty++;
    addReplyLongLong(c,totlen);
}

void strlenCommand(redisClient *c) {
    robj *o;
    if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
        checkType(c,o,REDIS_STRING)) return;
    addReplyLongLong(c,stringObjectLen(o));
}