124 lines
4.2 KiB
C#
124 lines
4.2 KiB
C#
using System.Drawing;
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using System.Net.NetworkInformation;
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namespace SHH.CameraSdk;
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/// <summary>
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/// [状态代理] 网络连通性哨兵
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/// 特性：
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/// 1. 低耦合：不依赖具体驱动，只依赖接口
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/// 2. 高性能：使用 Parallel.ForEachAsync 实现受控并行
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/// 3. 智能策略：播放中不Ping，空闲时才Ping
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/// </summary>
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public class ConnectivitySentinel
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{
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private readonly CameraManager _manager; // [cite: 329]
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private readonly PeriodicTimer _timer;
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private readonly CancellationTokenSource _cts = new();
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// [关键] 状态缓存：用于“去重”。
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// 只有当状态真的从 true 变 false (或反之) 时，才通知 Manager。
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// 防止每 3 秒发一次 "在线" 骚扰上层。
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private readonly ConcurrentDictionary<long, bool> _lastStates = new();
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// [关键配置] 最大并发度
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// 建议值：CPU 核心数 * 4，或者固定 16-32
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// 50 个摄像头，设为 16，意味着分 4 批完成，总耗时极短
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private const int MAX_PARALLELISM = 16;
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public ConnectivitySentinel(CameraManager manager)
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{
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_manager = manager;
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// 每 3 秒执行一轮全量巡检
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_timer = new PeriodicTimer(TimeSpan.FromSeconds(3));
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// 启动后台任务（不阻塞主线程）
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_ = RunLoopAsync();
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}
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private async Task RunLoopAsync()
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{
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try
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{
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// 等待下一个 3秒 周期
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while (await _timer.WaitForNextTickAsync(_cts.Token))
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{
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// 1. 获取当前所有设备的快照
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// CameraManager.GetAllDevices() 返回的是 BaseVideoSource，它实现了 IDeviceConnectivity
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var devices = _manager.GetAllDevices().Cast<IDeviceConnectivity>();
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// 2. [核心回答] 受控并行执行
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// .NET 6+ 提供的超级 API，专门解决“一下子 50 个”的问题
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await Parallel.ForEachAsync(devices, new ParallelOptions
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{
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MaxDegreeOfParallelism = MAX_PARALLELISM,
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CancellationToken = _cts.Token
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},
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async (device, token) =>
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{
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// 对每个设备执行独立检查
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await CheckSingleDeviceAsync(device);
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});
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}
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}
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catch (OperationCanceledException) { /* 正常停止 */ }
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}
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private async Task CheckSingleDeviceAsync(IDeviceConnectivity device)
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{
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bool isAlive = false;
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// [智能策略]：如果设备正在取流，直接检查帧心跳（省流模式）
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if (device.Status == VideoSourceStatus.Playing || device.Status == VideoSourceStatus.Streaming)
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{
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long now = Environment.TickCount64;
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// 5秒内有帧，就算在线
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isAlive = (now - device.LastFrameTick) < 5000;
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}
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else
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{
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// [主动探测]：空闲或离线时，发射 ICMP Ping
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isAlive = await PingAsync(device.IpAddress);
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}
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// [状态注入]：将探测结果“注入”回设备
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device.SetNetworkStatus(isAlive);
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// 3. [状态去重与上报]
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// 获取上一次的状态，如果没记录过，假设它之前是反状态(强制第一次上报)
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bool lastState = _lastStates.TryGetValue(device.Id, out bool val) ? val : !isAlive;
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if (lastState != isAlive)
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{
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// 记录新状态
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_lastStates[device.Id] = isAlive;
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// ★★★ 核心动作：只通知 Manager，不做任何网络操作 ★★★
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_manager.NotifyStatusChange(device.Id, isAlive, "网络连通性哨兵检测结论");
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// Console.WriteLine($"[Sentinel] 诊断变化: {device.Id} -> {isAlive}");
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}
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}
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// 纯粹的 Ping 逻辑
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private async Task<bool> PingAsync(string ip)
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{
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try
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{
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using var ping = new Ping();
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// 超时设为 800ms，快速失败，避免拖慢整体批次
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var reply = await ping.SendPingAsync(ip, 800);
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return reply.Status == IPStatus.Success;
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}
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catch
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{
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return false;
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}
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}
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public void Stop()
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{
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_cts.Cancel();
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_timer.Dispose();
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}
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} |