C++ dbAdd函数代码示例

void rpoplpushHandlePush(redisClient *c, robj *dstkey, robj *dstobj, robj *value) {
    /* Create the list if the key does not exist */
    if (!dstobj) {
        dstobj = createZiplistObject();
        dbAdd(c->db,dstkey,dstobj);
        signalListAsReady(c,dstkey);
    }
    signalModifiedKey(c->db,dstkey);
    listTypePush(dstobj,value,REDIS_HEAD);
    /* Always send the pushed value to the client. */
    addReplyBulk(c,value);
}

void rpoplpushHandlePush(redisClient *c, robj *dstkey, robj *dstobj, robj *value) {
    /* Create the list if the key does not exist */
    if (!dstobj) {
        dstobj = createZiplistObject();
        dbAdd(c->db,dstkey,dstobj);
    }
    signalModifiedKey(c->db,dstkey);
    listTypePush(dstobj,value,REDIS_HEAD);
    notifyKeyspaceEvent(REDIS_NOTIFY_LIST,"lpush",dstkey,c->db->id);
    /* Always send the pushed value to the client. */
    addReplyBulk(c,value);
}

void moveCommand(redisClient *c) {
    robj *o;
    redisDb *src, *dst;
    int srcid;
    long long dbid;

    if (server.cluster_enabled) {
        addReplyError(c,"MOVE is not allowed in cluster mode");
        return;
    }

    /* Obtain source and target DB pointers */
    src = c->db;
    srcid = c->db->id;

    if (getLongLongFromObject(c->argv[2],&dbid) == REDIS_ERR ||
            dbid < INT_MIN || dbid > INT_MAX ||
            selectDb(c,dbid) == REDIS_ERR)
    {
        addReply(c,shared.outofrangeerr);
        return;
    }
    dst = c->db;
    selectDb(c,srcid); /* Back to the source DB */

    /* If the user is moving using as target the same
     * DB as the source DB it is probably an error. */
    if (src == dst) {
        addReply(c,shared.sameobjecterr);
        return;
    }

    /* Check if the element exists and get a reference */
    o = lookupKeyWrite(c->db,c->argv[1]);
    if (!o) {
        addReply(c,shared.czero);
        return;
    }

    /* Return zero if the key already exists in the target DB */
    if (lookupKeyWrite(dst,c->argv[1]) != NULL) {
        addReply(c,shared.czero);
        return;
    }
    dbAdd(dst,c->argv[1],o);
    incrRefCount(o);

    /* OK! key moved, free the entry in the source DB */
    dbDelete(src,c->argv[1]);
    server.dirty++;
    addReply(c,shared.cone);
}

void smoveCommand(redisClient *c) {
    robj *srcset, *dstset, *ele;
    srcset = lookupKeyWrite(c->db,c->argv[1]);
    dstset = lookupKeyWrite(c->db,c->argv[2]);
    ele = c->argv[3] = tryObjectEncoding(c->argv[3]);

    /* If the source key does not exist return 0 */
    if (srcset == NULL) {
        addReply(c,shared.czero);
        return;
    }

    /* If the source key has the wrong type, or the destination key
     * is set and has the wrong type, return with an error. */
    if (checkType(c,srcset,REDIS_SET) ||
        (dstset && checkType(c,dstset,REDIS_SET))) return;

    /* If srcset and dstset are equal, SMOVE is a no-op */
    if (srcset == dstset) {
        addReply(c,shared.cone);
        return;
    }

    /* If the element cannot be removed from the src set, return 0. */
    if (!setTypeRemove(srcset,ele)) {
        addReply(c,shared.czero);
        return;
    }
    notifyKeyspaceEvent(REDIS_NOTIFY_SET,"srem",c->argv[1],c->db->id);

    /* Remove the src set from the database when empty */
    if (setTypeSize(srcset) == 0) {
        dbDelete(c->db,c->argv[1]);
        notifyKeyspaceEvent(REDIS_NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
    }
    signalModifiedKey(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[2]);
    server.dirty++;

    /* Create the destination set when it doesn't exist */
    if (!dstset) {
        dstset = setTypeCreate(ele);
        dbAdd(c->db,c->argv[2],dstset);
    }

    /* An extra key has changed when ele was successfully added to dstset */
    if (setTypeAdd(dstset,ele)) {
        server.dirty++;
        notifyKeyspaceEvent(REDIS_NOTIFY_SET,"sadd",c->argv[2],c->db->id);
    }
    addReply(c,shared.cone);
}

robj* hashTypeLookupWriteElseCreate(caller_t *c, robj *key)
{
    robj *o = lookupKeyWrite(c->db,key);
    if (o == NULL) {
        o = createHashObject();
        dbAdd(c->db,key,o);
    } else {
        if (o->type != REDIS_HASH) {
            caller_set_err(c, ERR_TYPE);
            return NULL;
        }
    }
    return o;
}

void rpoplpushHandlePush(client *c, robj *dstkey, robj *dstobj, robj *value) {
    /* Create the list if the key does not exist */
    if (!dstobj) {
        dstobj = createQuicklistObject();
        quicklistSetOptions(dstobj->ptr, server.list_max_ziplist_size,
                            server.list_compress_depth);
        dbAdd(c->db,dstkey,dstobj);
    }
    signalModifiedKey(c->db,dstkey);
    listTypePush(dstobj,value,LIST_HEAD);
    notifyKeyspaceEvent(NOTIFY_LIST,"lpush",dstkey,c->db->id);
    /* Always send the pushed value to the client. */
    addReplyBulk(c,value);
}

void rpoplpushHandlePush(redisClient *c, robj *dstkey, robj *dstobj, robj *value) {
    if (!handleClientsWaitingListPush(c,dstkey,value)) {
        /* Create the list if the key does not exist */
        if (!dstobj) {
            dstobj = createZiplistObject();
            dbAdd(c->db,dstkey,dstobj);
        } else {
            touchWatchedKey(c->db,dstkey);
            server.dirty++;
        }
        listTypePush(dstobj,value,REDIS_HEAD);
    }

    /* Always send the pushed value to the client. */
    addReplyBulk(c,value);
}

void moveCommand(redisClient *c) {
    robj *o;
    redisDb *src, *dst;
    int srcid;

    if (server.cluster_enabled) {
        addReplyError(c,"MOVE is not allowed in cluster mode");
        return;
    }

    /* Obtain source and target DB pointers */
    src = c->db;
    srcid = c->db->id;
    if (selectDb(c,atoi(c->argv[2]->ptr)) == REDIS_ERR) {
        addReply(c,shared.outofrangeerr);
        return;
    }
    dst = c->db;
    selectDb(c,srcid); /* Back to the source DB */

    /* If the user is moving using as target the same
     * DB as the source DB it is probably an error. */
    if (src == dst) {
        addReply(c,shared.sameobjecterr);
        return;
    }

    /* Check if the element exists and get a reference */
    o = lookupKeyWrite(c->db,c->argv[1]);
    if (!o) {
        addReply(c,shared.czero);
        return;
    }

    /* Try to add the element to the target DB */
    if (dbAdd(dst,c->argv[1],o) == REDIS_ERR) {
        addReply(c,shared.czero);
        return;
    }
    incrRefCount(o);

    /* OK! key moved, free the entry in the source DB */
    dbDelete(src,c->argv[1]);
    server.dirty++;
    addReply(c,shared.cone);
}

void pushGenericCommand(redisClient *c, int where) {
    int j, waiting = 0, pushed = 0;
    robj *lobj = lookupKeyWrite(c->db,c->argv[1]);
    int may_have_waiting_clients = (lobj == NULL);

    if (lobj && lobj->type != REDIS_LIST) {
        addReply(c,shared.wrongtypeerr);
        return;
    }

    for (j = 2; j < c->argc; j++) {
        c->argv[j] = tryObjectEncoding(c->argv[j]);
        if (may_have_waiting_clients) {
            if (handleClientsWaitingListPush(c,c->argv[1],c->argv[j])) {
                waiting++;
                continue;
            } else {
                may_have_waiting_clients = 0;
            }
        }
        if (!lobj) {
            lobj = createZiplistObject();
            dbAdd(c->db,c->argv[1],lobj);
        }
        listTypePush(lobj,c->argv[j],where);
        pushed++;
    }
    addReplyLongLong(c, waiting + (lobj ? listTypeLength(lobj) : 0));
    if (pushed) signalModifiedKey(c->db,c->argv[1]);
    server.dirty += pushed;

    /* Alter the replication of the command accordingly to the number of
     * list elements delivered to clients waiting into a blocking operation.
     * We do that only if there were waiting clients, and only if still some
     * element was pushed into the list (othewise dirty is 0 and nothign will
     * be propagated). */
    if (waiting && pushed) {
        /* CMD KEY a b C D E */
        for (j = 0; j < waiting; j++) decrRefCount(c->argv[j+2]);
        memmove(c->argv+2,c->argv+2+waiting,sizeof(robj*)*pushed);
        c->argc -= waiting;
    }
}

//PUSH命令的底层实现，where保存push的位置
void pushGenericCommand(client *c, int where) {
    int j, waiting = 0, pushed = 0;
    robj *lobj = lookupKeyWrite(c->db,c->argv[1]);  //以写操作读取key对象的value

    //如果value对象不是列表类型则发送错误信息，返回
    if (lobj && lobj->type != OBJ_LIST) {
        addReply(c,shared.wrongtypeerr);
        return;
    }

    //从第一个value开始遍历
    for (j = 2; j < c->argc; j++) {
        c->argv[j] = tryObjectEncoding(c->argv[j]);     //将value对象优化编码
        //如果没有找到key对象
        if (!lobj) {
            //创建一个quicklist类型的对象
            lobj = createQuicklistObject();
            //设置ziplist最大的长度和压缩程度，配置文件指定
            quicklistSetOptions(lobj->ptr, server.list_max_ziplist_size,
                                server.list_compress_depth);
            //将新的key对象和优化编码过的value对象进行组成键值对
            dbAdd(c->db,c->argv[1],lobj);
        }

        //在where推入一个value对象
        listTypePush(lobj,c->argv[j],where);
        pushed++;   //更新计数器
    }
    //发送当前列表中元素的个数
    addReplyLongLong(c, waiting + (lobj ? listTypeLength(lobj) : 0));
    //如果推入元素成功
    if (pushed) {
        char *event = (where == LIST_HEAD) ? "lpush" : "rpush";

        //当数据库的键被改动，则会调用该函数发送信号
        signalModifiedKey(c->db,c->argv[1]);
        //发送"lpush"或"rpush"事件通知
        notifyKeyspaceEvent(NOTIFY_LIST,event,c->argv[1],c->db->id);
    }
    server.dirty += pushed; //更新脏键
}

void renameGenericCommand(client *c, int nx) {
    robj *o;
    long long expire;
    int samekey = 0;

    /* When source and dest key is the same, no operation is performed,
     * if the key exists, however we still return an error on unexisting key. */
    if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) samekey = 1;

    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
        return;

    if (samekey) {
        addReply(c,nx ? shared.czero : shared.ok);
        return;
    }

    incrRefCount(o);
    expire = getExpire(c->db,c->argv[1]);
    if (lookupKeyWrite(c->db,c->argv[2]) != NULL) {
        if (nx) {
            decrRefCount(o);
            addReply(c,shared.czero);
            return;
        }
        /* Overwrite: delete the old key before creating the new one
         * with the same name. */
        dbDelete(c->db,c->argv[2]);
    }
    dbAdd(c->db,c->argv[2],o);
    if (expire != -1) setExpire(c->db,c->argv[2],expire);
    dbDelete(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[1]);
    signalModifiedKey(c->db,c->argv[2]);
    notifyKeyspaceEvent(NOTIFY_GENERIC,"rename_from",
        c->argv[1],c->db->id);
    notifyKeyspaceEvent(NOTIFY_GENERIC,"rename_to",
        c->argv[2],c->db->id);
    server.dirty++;
    addReply(c,nx ? shared.cone : shared.ok);
}

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

#ifdef AUTH_FEATURE
    /* Check mod permissions */
    if (authCheckModOrReply(c) == REDIS_ERR)
      return;
    /* Check permissions */
    if (authCheckPathOrReply(c, key) == REDIS_ERR)
      return;
#endif

    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);
    }
    touchWatchedKey(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 appendCommand(redisClient *c) {
    int retval;
    size_t totlen;
    robj *o;

    o = lookupKeyWrite(c->db,c->argv[1]);
    c->argv[2] = tryObjectEncoding(c->argv[2]);
    if (o == NULL) {
        /* Create the key */
        retval = dbAdd(c->db,c->argv[1],c->argv[2]);
        incrRefCount(c->argv[2]);
        totlen = stringObjectLen(c->argv[2]);
    } else {
        if (o->type != REDIS_STRING) {
            addReply(c,shared.wrongtypeerr);
            return;
        }
        /* If the object is specially encoded or shared 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! */
        if (c->argv[2]->encoding == REDIS_ENCODING_RAW) {
            o->ptr = sdscatlen(o->ptr,
                c->argv[2]->ptr, sdslen(c->argv[2]->ptr));
        } else {
            o->ptr = sdscatprintf(o->ptr, "%ld",
                (unsigned long) c->argv[2]->ptr);
        }
        totlen = sdslen(o->ptr);
    }
    touchWatchedKey(c->db,c->argv[1]);
    server.dirty++;
    addReplyLongLong(c,totlen);
}

//将一个value推入到列表头部，被rpoplpushCommand调用
void rpoplpushHandlePush(client *c, robj *dstkey, robj *dstobj, robj *value) {
    /* Create the list if the key does not exist */
    //如果目标dstkey不存在
    if (!dstobj) {
        //创建一个quicklist对象
        dstobj = createQuicklistObject();
        //设置ziplist的最大长度和压缩程度
        quicklistSetOptions(dstobj->ptr, server.list_max_ziplist_size,
                            server.list_compress_depth);
        //将key添加到数据库中
        dbAdd(c->db,dstkey,dstobj);
    }
    //当数据库的键被改动，则会调用该函数发送信号
    signalModifiedKey(c->db,dstkey);
    //将vlaue推入到列表的头部
    listTypePush(dstobj,value,LIST_HEAD);
    //发送"lpush"时间通知
    notifyKeyspaceEvent(NOTIFY_LIST,"lpush",dstkey,c->db->id);
    /* Always send the pushed value to the client. */
    //将value值发送给client
    addReplyBulk(c,value);
}

void saddCommand(redisClient *c) {
    robj *set;

    set = lookupKeyWrite(c->db,c->argv[1]);
    c->argv[2] = tryObjectEncoding(c->argv[2]);
    if (set == NULL) {
        set = setTypeCreate(c->argv[2]);
        dbAdd(c->db,c->argv[1],set);
    } else {
        if (set->type != REDIS_SET) {
            addReply(c,shared.wrongtypeerr);
            return;
        }
    }
    if (setTypeAdd(set,c->argv[2])) {
        touchWatchedKey(c->db,c->argv[1]);
        server.dirty++;
        addReply(c,shared.cone);
    } else {
        addReply(c,shared.czero);
    }
}