Exemplos de quicklistDelRange em C++ (Cpp)

Exemplo n.º 1

Arquivo: t_list.c Projeto: therenine/redis_source_annotation

// LTRIM key start stop
// LTRIM命令实现
void ltrimCommand(client *c) {
    robj *o;
    long start, end, llen, ltrim, rtrim;

    //将字符串类型起始地址start和结束地址end转换为long类型保存在start和end中
    //如果任意失败，则直接返回
    if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != C_OK) ||
        (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != C_OK)) return;

    // 以读操作取出key大小的value值，如果value对象不是列表类型，直接返回
    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.ok)) == NULL ||
        checkType(c,o,OBJ_LIST)) return;
    //获取列表元素数量
    llen = listTypeLength(o);

    /* convert negative indexes */
    // 将负数范围转换成合法范围
    if (start < 0) start = llen+start;
    if (end < 0) end = llen+end;
    if (start < 0) start = 0;

    /* Invariant: start >= 0, so this test will be true when end < 0.
     * The range is empty when start > end or start >= length. */
    //不合理的范围，移除所有的元素
    if (start > end || start >= llen) {
        /* Out of range start or start > end result in empty list */
        ltrim = llen;
        rtrim = 0;
    } else {
        if (end >= llen) end = llen-1;  //end值不能超过元素个数
        ltrim = start;      //左边界
        rtrim = llen-end-1; //右边界
    }

    /* Remove list elements to perform the trim */
    //只对编码为quicklist类型的value对象操作
    if (o->encoding == OBJ_ENCODING_QUICKLIST) {
        quicklistDelRange(o->ptr,0,ltrim);      //删除左边界以左的所有元素
        quicklistDelRange(o->ptr,-rtrim,rtrim); //删除左边界以右的所有元素
    } else {
        serverPanic("Unknown list encoding");
    }

    //发送"ltrim"事件通知
    notifyKeyspaceEvent(NOTIFY_LIST,"ltrim",c->argv[1],c->db->id);
    //如果将所有元素全部删除完了
    if (listTypeLength(o) == 0) {
        //从数据库中删除该key
        dbDelete(c->db,c->argv[1]);
        //发送"del"时间通知
        notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
    }
    //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]);
    //更新脏键
    server.dirty++;
    //发送ok信息给client
    addReply(c,shared.ok);
}

Exemplo n.º 2

Arquivo: t_list.c Projeto: RealHacker/redis-plus

void ltrimCommand(client *c) {
    robj *o;
    long start, end, llen, ltrim, rtrim;

    if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != C_OK) ||
        (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != C_OK)) return;

    if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.ok)) == NULL ||
        checkType(c,o,OBJ_LIST)) return;
    llen = listTypeLength(o);

    /* convert negative indexes */
    if (start < 0) start = llen+start;
    if (end < 0) end = llen+end;
    if (start < 0) start = 0;

    /* Invariant: start >= 0, so this test will be true when end < 0.
     * The range is empty when start > end or start >= length. */
    if (start > end || start >= llen) {
        /* Out of range start or start > end result in empty list */
        ltrim = llen;
        rtrim = 0;
    } else {
        if (end >= llen) end = llen-1;
        ltrim = start;
        rtrim = llen-end-1;
    }

    /* Remove list elements to perform the trim */
    if (o->encoding == OBJ_ENCODING_QUICKLIST) {
        quicklistDelRange(o->ptr,0,ltrim);
        quicklistDelRange(o->ptr,-rtrim,rtrim);
    } else {
        serverPanic("Unknown list encoding");
    }

    notifyKeyspaceEvent(NOTIFY_LIST,"ltrim",c->argv[1],c->db->id);
    if (listTypeLength(o) == 0) {
        dbDelete(c->db,c->argv[1]);
        notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
    }
    signalModifiedKey(c->db,c->argv[1]);
    server.dirty++;
    addReply(c,shared.ok);
}