ThingsGateway/framework/ThingsGateway.Foundation/DataHandleAdapter/ReadWriteDevicesTcpDataHandleAdapter.cs

#region copyright
//------------------------------------------------------------------------------
//  此代码版权声明为全文件覆盖，如有原作者特别声明，会在下方手动补充
//  此代码版权（除特别声明外的代码）归作者本人Diego所有
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//  Gitee源代码仓库：https://gitee.com/diego2098/ThingsGateway
//  Github源代码仓库：https://github.com/kimdiego2098/ThingsGateway
//  使用文档：https://diego2098.gitee.io/thingsgateway-docs/
//  QQ群：605534569
//------------------------------------------------------------------------------
#endregion

using ThingsGateway.Foundation.Extension.Byte;
using ThingsGateway.Foundation.Extension.Generic;

namespace ThingsGateway.Foundation;

/// <summary>
/// TCP适配器基类
/// </summary>
public abstract class ReadWriteDevicesTcpDataHandleAdapter<TRequest> : CustomDataHandlingAdapter<TRequest> where TRequest : class, IMessage
{
    /// <inheritdoc cref="ReadWriteDevicesTcpDataHandleAdapter{TRequest}"/>
    public ReadWriteDevicesTcpDataHandleAdapter()
    {
        Request = GetInstance();
    }
    /// <inheritdoc/>
    public override bool CanSendRequestInfo => false;

    /// <inheritdoc/>
    public override bool CanSplicingSend => false;

    /// <inheritdoc/>
    public virtual bool IsSendPackCommand { get; set; } = true;

    /// <inheritdoc/>
    public TRequest Request { get; set; }

    /// <summary>
    /// 发送前，对当前的命令进行打包处理
    /// </summary>
    public abstract byte[] PackCommand(byte[] command);

    /// <inheritdoc/>
    protected override FilterResult Filter(in ByteBlock byteBlock, bool beCached, ref TRequest request, ref int tempCapacity)
    {
        //获取全部内容
        var allBytes = byteBlock.ToArray(0, byteBlock.Len);
        Logger?.Trace(FoundationConst.LogMessageHeader + " - " + ThingsGatewayStatus.Received.GetDescription() + ":" + allBytes.ToHexString(" "));
        //缓存/不缓存解析一样，因为游标已经归0
        {
            request = Request;

            if (request.HeadBytesLength > byteBlock.CanReadLen)
            {
                return FilterResult.Cache;//当头部都无法解析时，直接缓存
            }

            var pos = byteBlock.Pos;//记录初始游标位置，防止本次无法解析时，回退游标。

            byte[] header = new byte[] { };
            if (request.HeadBytesLength > 0)
            {
                //当解析消息设定固定头长度大于0时，获取头部字节
                byteBlock.Read(out header, request.HeadBytesLength);
            }
            //检查头部合法性
            if (request.CheckHeadBytes(header))
            {
                if (request.BodyLength > byteBlock.CanReadLen)
                {
                    //body不满足解析，开始缓存，然后保存对象
                    byteBlock.Pos = pos;//回退游标
                    request.ReceivedBytes = header;
                    return FilterResult.Cache;
                }
                if (request.BodyLength <= 0)
                {
                    //如果body长度无法确定，直接读取全部
                    request.BodyLength = byteBlock.Len;
                }

                byteBlock.Read(out byte[] body, request.BodyLength);

                var bytes = request.HeadBytes.SpliceArray(body);
                return GetResponse(byteBlock, request, body, bytes);
            }
            else
            {
                byteBlock.Pos = byteBlock.Len;//移动游标
                return FilterResult.GoOn;//放弃解析
            }
        }
    }
    /// <summary>
    /// 获取泛型实例。
    /// </summary>
    /// <returns></returns>
    protected abstract TRequest GetInstance();

    /// <summary>
    /// 解包获取实际数据包
    /// <para>当不满足解析条件时，请返回<see cref="FilterResult.Cache"/>，此时会保存<see cref="ByteBlock.CanReadLen"/>的数据</para>
    /// <para>当数据部分异常时，请移动<see cref="ByteBlock.Pos"/>到指定位置，然后返回<see cref="FilterResult.GoOn"/></para>
    /// <para>当完全满足解析条件时，请返回<see cref="FilterResult.Success"/>最后将<see cref="ByteBlock.Pos"/>移至指定位置。</para>
    /// </summary>
    protected virtual FilterResult GetResponse(ByteBlock byteBlock, TRequest request, byte[] body, byte[] bytes)
    {
        var unpackbytes = UnpackResponse(request, request.SendBytes, body, bytes);
        request.ReceivedBytes = bytes;
        switch (unpackbytes)
        {
            case FilterResult.Cache:
                return FilterResult.Cache;
            case FilterResult.Success:
                return FilterResult.Success;
            case FilterResult.GoOn:
                byteBlock.Pos = byteBlock.Len;
                return FilterResult.GoOn;
            default:
                byteBlock.Pos = byteBlock.Len;
                return FilterResult.GoOn;
        }
    }
    /// <summary>
    /// 发送方法,会重新建立<see cref="Request"/>
    /// </summary>
    protected void GoSend(byte[] item)
    {
        byte[] bytes;
        if (IsSendPackCommand)
            bytes = PackCommand(item);
        else
            bytes = item;
        Request = GetInstance();
        Request.SendBytes = bytes;
        GoSend(bytes, 0, bytes.Length);
        Logger?.Trace(FoundationConst.LogMessageHeader + " - " + ThingsGatewayStatus.Send.GetDescription() + ":" + Request.SendBytes.ToHexString(" "));
    }

    /// <inheritdoc/>
    protected override void PreviewSend(byte[] buffer, int offset, int length)
    {
        GoSend(buffer);
    }

    /// <summary>
    /// 报文拆包
    /// </summary>
    protected abstract FilterResult UnpackResponse(TRequest request, byte[] send, byte[] body, byte[] response);
}