LibUv Networking (#65)

Projects/Server/LibUv/Internal/UvAsyncHandle.cs

@@ -0,0 +1,72 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics;
+using System.Threading;
+
+namespace Libuv.Internal
+{
+  public class UvAsyncHandle : UvHandle
+  {
+    private static readonly LibuvFunctions.uv_close_cb _destroyMemory = handle => DestroyMemory(handle);
+
+    private static readonly LibuvFunctions.uv_async_cb _uv_async_cb = handle => AsyncCb(handle);
+    private Action _callback;
+    private Action<Action<IntPtr>, IntPtr> _queueCloseHandle;
+
+    public UvAsyncHandle(ILibuvTrace logger) : base(logger)
+    {
+    }
+
+    public void Init(UvLoopHandle loop, Action callback, Action<Action<IntPtr>, IntPtr> queueCloseHandle)
+    {
+      CreateMemory(
+        loop.Libuv,
+        loop.ThreadId,
+        loop.Libuv.handle_size(LibuvFunctions.HandleType.ASYNC));
+
+      _callback = callback;
+      _queueCloseHandle = queueCloseHandle;
+      _uv.async_init(loop, this, _uv_async_cb);
+    }
+
+    public void Send()
+    {
+      _uv.async_send(this);
+    }
+
+    private static void AsyncCb(IntPtr handle)
+    {
+      FromIntPtr<UvAsyncHandle>(handle)._callback.Invoke();
+    }
+
+    protected override bool ReleaseHandle()
+    {
+      var memory = handle;
+      if (memory != IntPtr.Zero)
+      {
+        handle = IntPtr.Zero;
+
+        if (Thread.CurrentThread.ManagedThreadId == ThreadId)
+        {
+          _uv.close(memory, _destroyMemory);
+        }
+        else if (_queueCloseHandle != null)
+        {
+          // This can be called from the finalizer.
+          // Ensure the closure doesn't reference "this".
+          LibuvFunctions uv = _uv;
+          _queueCloseHandle(memory2 => uv.close(memory2, _destroyMemory), memory);
+          uv.unsafe_async_send(memory);
+        }
+        else
+        {
+          Debug.Assert(false, "UvAsyncHandle not initialized with queueCloseHandle action");
+          return false;
+        }
+      }
+      return true;
+    }
+  }
+}