using System.IO;
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using System.IO.Pipes;
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using System.Text;
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namespace DeviceService.Service.NamePipe
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{
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/// <summary>
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/// 命名管道客户端连接封装。
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/// 每个实例对应管道服务端上的一条已建立连接，收发均通过 <see cref="StreamReader"/> / <see cref="StreamWriter"/> 完成。
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/// 协议约定：每条消息为一行 UTF-8 文本（以 \n 结尾），发送端单次写入“内容+换行”，
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/// 使 Message 模式下一条消息恰好是完整的一行。
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/// </summary>
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public class NamePipeClient : IClient, IDisposable
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{
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/// <summary>单条消息允许的最大字节数（16MB）。</summary>
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internal const int MaxMessageLength = 16 * 1024 * 1024;
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/// <summary>等待发送锁的超时时间（毫秒）。</summary>
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private const int SendLockTimeout = 5000;
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/// <summary>消息行结束符。StreamWriter 每次写入都会触发 AutoFlush，必须与内容在同一次 Write 中写入。</summary>
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private const char LineEnding = '\n';
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private readonly NamedPipeServerStream _stream;
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private readonly StreamWriter writer;
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private readonly StreamReader reader;
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private readonly SemaphoreSlim _sendLock = new SemaphoreSlim(1, 1);
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private volatile bool _disposed;
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public NamePipeClient(NamedPipeServerStream serverStream)
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{
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var encoding = new UTF8Encoding(false);
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_stream = serverStream;
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reader = new StreamReader(serverStream, encoding, false, 1024, true);
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writer = new StreamWriter(serverStream, encoding, 1024, true) { AutoFlush = true };
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}
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/// <summary>连接是否仍然可用。</summary>
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public bool IsConnected
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{
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get
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{
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if (_disposed)
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{
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return false;
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}
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return _stream.IsConnected;
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}
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}
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public bool Send(string data, out string msg)
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{
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if (data == null)
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{
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msg = "待发送的数据不能为空。";
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return false;
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}
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return SendLine(data, Encoding.UTF8.GetByteCount(data) + 1, out msg);
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}
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public bool Send(byte[] data, out string msg)
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{
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if (data == null)
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{
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msg = "待发送的数据不能为空。";
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return false;
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}
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// 负载按 UTF-8 文本处理，与行协议保持一致
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return SendLine(Encoding.UTF8.GetString(data), data.Length + 1, out msg);
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}
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/// <summary>
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/// 写入一行消息。内容与换行符必须单次 Write 写入，配合 AutoFlush 才能成为一条完整消息。
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/// </summary>
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private bool SendLine(string text, int byteLength, out string msg)
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{
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if (byteLength > MaxMessageLength)
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{
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msg = $"数据长度 {byteLength} 字节超过单条消息上限 {MaxMessageLength} 字节。";
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return false;
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}
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if (_disposed)
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{
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msg = "管道连接已关闭，无法发送数据。";
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return false;
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}
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if (!IsConnected)
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{
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msg = "管道连接已断开，无法发送数据。";
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return false;
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}
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bool lockTaken = false;
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try
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{
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lockTaken = _sendLock.Wait(SendLockTimeout);
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if (!lockTaken)
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{
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msg = "发送超时：上一条数据仍未写出。";
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return false;
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}
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// writer 非 thread-safe，统一由 _sendLock 串行化
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writer.Write(text + LineEnding);
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writer.Flush();
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msg = string.Empty;
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return true;
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}
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catch (Exception ex)
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{
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msg = $"发送失败：{ex.Message}";
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return false;
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}
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finally
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{
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if (lockTaken)
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{
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_sendLock.Release();
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}
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}
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}
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/// <summary>
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/// 读取一行消息。返回 null 表示对端已关闭连接。
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/// </summary>
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internal async Task<string?> ReadMessageAsync()
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{
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if (_disposed)
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{
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return null;
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}
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string? line = await reader.ReadLineAsync().ConfigureAwait(false);
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return line;
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}
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public void Dispose()
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{
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if (_disposed)
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{
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return;
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}
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_disposed = true;
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try
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{
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reader.Dispose();
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}
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catch
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{
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// 忽略关闭异常
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}
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try
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{
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writer.Dispose();
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}
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catch
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{
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// 忽略关闭异常
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}
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try
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{
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_stream.Dispose();
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}
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catch
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{
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// 关闭过程中的异常可以忽略
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}
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_sendLock.Dispose();
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}
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}
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}
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