Add live debugger frontend and mutex stall recovery (#383)

2026-07-31 15:09:42 +08:00 · 2026-07-17 22:41:07 -06:00
parent 1c8cdd6537
commit 13269797bf
57 changed files with 6534 additions and 22 deletions
@@ -0,0 +1,158 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Net.Sockets;
+using System.Text;
+using SharpEmu.Debugger.Protocol;
+using SharpEmu.Debugger.Session;
+using SharpEmu.Logging;
+
+namespace SharpEmu.Debugger.Server;
+
+/// <summary>
+/// Services a single connected client: reads requests, dispatches them against
+/// the shared session, and pushes session lifecycle events. Writes from the
+/// request loop and from event callbacks are serialised through one lock so the
+/// two never interleave a half-written line.
+/// </summary>
+internal sealed class DebuggerClientConnection : IAsyncDisposable
+{
+    private static readonly SharpEmuLogger Log = SharpEmuLog.For("SharpEmu.Debugger");
+    private static readonly UTF8Encoding Utf8NoBom = new(encoderShouldEmitUTF8Identifier: false);
+
+    private readonly TcpClient _client;
+    private readonly IDebuggerSession _session;
+    private readonly IDebugProtocol _protocol;
+    private readonly DebugCommandDispatcher _dispatcher;
+    private readonly SemaphoreSlim _writeLock = new(1, 1);
+
+    private TextWriter? _writer;
+    private CancellationToken _cancellationToken;
+
+    public DebuggerClientConnection(TcpClient client, IDebuggerSession session, IDebugProtocol protocol)
+    {
+        _client = client;
+        _session = session;
+        _protocol = protocol;
+        _dispatcher = new DebugCommandDispatcher(session);
+    }
+
+    public async Task RunAsync(CancellationToken cancellationToken)
+    {
+        _cancellationToken = cancellationToken;
+        var endpoint = _client.Client.RemoteEndPoint?.ToString() ?? "unknown";
+        Log.Info($"Debugger client connected: {endpoint}");
+
+        using var stream = _client.GetStream();
+        using var reader = new StreamReader(stream, Utf8NoBom);
+        await using var writer = new StreamWriter(stream, Utf8NoBom) { AutoFlush = false };
+        _writer = writer;
+
+        _session.Stopped += OnStopped;
+        _session.Resumed += OnResumed;
+        _session.Terminated += OnTerminated;
+        try
+        {
+            await SendEventAsync("hello", new Dictionary<string, object?>
+            {
+                ["protocol"] = _protocol.Name,
+                ["state"] = _session.State.ToString(),
+            }).ConfigureAwait(false);
+
+            while (!cancellationToken.IsCancellationRequested)
+            {
+                var request = await _protocol.ReadRequestAsync(reader, cancellationToken).ConfigureAwait(false);
+                if (request is null)
+                {
+                    break;
+                }
+
+                var response = _dispatcher.Dispatch(request);
+                await WriteResponseAsync(response).ConfigureAwait(false);
+            }
+        }
+        catch (OperationCanceledException)
+        {
+            // Server shutting down.
+        }
+        catch (IOException)
+        {
+            // Client dropped the connection.
+        }
+        catch (Exception ex)
+        {
+            Log.Warn($"Debugger client error ({endpoint}): {ex.Message}");
+        }
+        finally
+        {
+            _session.Stopped -= OnStopped;
+            _session.Resumed -= OnResumed;
+            _session.Terminated -= OnTerminated;
+            _writer = null;
+            Log.Info($"Debugger client disconnected: {endpoint}");
+        }
+    }
+
+    private void OnStopped(object? sender, DebugStopEvent stop)
+        => _ = SendEventAsync("stopped", DebugCommandDispatcher.DescribeStop(stop));
+
+    private void OnResumed(object? sender, EventArgs e)
+        => _ = SendEventAsync("resumed", EmptyData);
+
+    private void OnTerminated(object? sender, EventArgs e)
+        => _ = SendEventAsync("terminated", EmptyData);
+
+    private async Task WriteResponseAsync(DebugResponse response)
+    {
+        var writer = _writer;
+        if (writer is null)
+        {
+            return;
+        }
+
+        await _writeLock.WaitAsync(_cancellationToken).ConfigureAwait(false);
+        try
+        {
+            await _protocol.WriteResponseAsync(writer, response, _cancellationToken).ConfigureAwait(false);
+        }
+        finally
+        {
+            _writeLock.Release();
+        }
+    }
+
+    private async Task SendEventAsync(string name, IReadOnlyDictionary<string, object?> data)
+    {
+        var writer = _writer;
+        if (writer is null)
+        {
+            return;
+        }
+
+        try
+        {
+            await _writeLock.WaitAsync(_cancellationToken).ConfigureAwait(false);
+            try
+            {
+                await _protocol.WriteEventAsync(writer, name, data, _cancellationToken).ConfigureAwait(false);
+            }
+            finally
+            {
+                _writeLock.Release();
+            }
+        }
+        catch (Exception ex) when (ex is IOException or OperationCanceledException or ObjectDisposedException)
+        {
+            // The client went away between the event firing and the write.
+        }
+    }
+
+    public ValueTask DisposeAsync()
+    {
+        _writeLock.Dispose();
+        _client.Dispose();
+        return ValueTask.CompletedTask;
+    }
+
+    private static readonly IReadOnlyDictionary<string, object?> EmptyData = new Dictionary<string, object?>();
+}