From ce5cfcb1bd0246b0ba0be1450c1d1e1b1e8dfaf1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 10:00:14 +0000
Subject: [PATCH 1/5] Implement ValueTaskSource-based channel operation waits
Agent-Logs-Url: https://github.com/OPCFoundation/UA-.NETStandard/sessions/24828edb-ccf0-41cb-b93d-218f7111aff6
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
---
.../Stack/Tcp/ChannelAsyncOperation.cs | 173 +++++++++++++-----
.../Stack/Tcp/UaSCBinaryClientChannel.cs | 8 +-
.../Transport/ChannelAsyncOperationTests.cs | 103 +++++++++++
3 files changed, 236 insertions(+), 48 deletions(-)
create mode 100644 Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
index feba487b4d..89ecc474db 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
@@ -31,6 +31,7 @@
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
+using System.Threading.Tasks.Sources;
using Microsoft.Extensions.Logging;
namespace Opc.Ua.Bindings
@@ -39,7 +40,7 @@ namespace Opc.Ua.Bindings
/// Stores the results of an asynchronous operation.
///
///
- public class ChannelAsyncOperation : IAsyncResult, IDisposable
+ public class ChannelAsyncOperation : IAsyncResult, IDisposable, IValueTaskSource, IValueTaskSource
{
///
/// Initializes the object with a callback
@@ -51,10 +52,14 @@ public ChannelAsyncOperation(int timeout, AsyncCallback? callback, object? async
m_synchronous = false;
m_completed = false;
m_logger = logger;
+ m_asyncWaitSource.RunContinuationsAsynchronously = true;
if (timeout is > 0 and not int.MaxValue)
{
- m_timer = new Timer(new TimerCallback(OnTimeout), null, timeout, Timeout.Infinite);
+ m_timeoutCancellationTokenSource = new CancellationTokenSource(timeout);
+ m_timeoutCancellationRegistration = m_timeoutCancellationTokenSource.Token.Register(
+ static state => ((ChannelAsyncOperation)state!).OnTimeout(),
+ this);
}
}
@@ -76,8 +81,9 @@ protected virtual void Dispose(bool disposing)
{
lock (m_lock)
{
- m_timer?.Dispose();
- m_timer = null;
+ m_timeoutCancellationRegistration.Dispose();
+ m_timeoutCancellationTokenSource?.Dispose();
+ m_timeoutCancellationTokenSource = null;
if (m_event != null)
{
@@ -86,13 +92,10 @@ protected virtual void Dispose(bool disposing)
m_event = null;
}
- if (m_tcs != null)
+ if (m_asyncWaitPending)
{
- if (!m_tcs.Task.IsCompleted)
- {
- m_tcs.TrySetCanceled();
- }
- m_tcs = null;
+ m_asyncWaitSource.SetException(new TaskCanceledException());
+ m_asyncWaitPending = false;
}
}
}
@@ -223,13 +226,25 @@ public T End(int timeout, bool throwOnError = true)
/// The awaitable response returned from the server.
///
///
- public async Task EndAsync(
+ public Task EndAsync(
+ int timeout,
+ bool throwOnError = true,
+ CancellationToken ct = default)
+ {
+ return EndValueTaskAsync(timeout, throwOnError, ct).AsTask();
+ }
+
+ ///
+ /// The low-allocation awaitable response returned from the server.
+ ///
+ internal async ValueTask EndValueTaskAsync(
int timeout,
bool throwOnError = true,
CancellationToken ct = default)
{
// check if the request has already completed.
bool mustWait = false;
+ ValueTask waitTask = default;
lock (m_lock)
{
@@ -237,8 +252,8 @@ public async Task EndAsync(
if (mustWait)
{
- m_tcs = new TaskCompletionSource(
- TaskCreationOptions.RunContinuationsAsynchronously);
+ m_asyncWaitPending = true;
+ waitTask = new ValueTask(this, m_asyncWaitSource.Version);
}
}
@@ -248,19 +263,13 @@ public async Task EndAsync(
bool badRequestInterrupted = false;
try
{
- Task awaitableTask = m_tcs!.Task;
- if (timeout != int.MaxValue)
+ if (timeout != int.MaxValue || ct != default)
{
- awaitableTask = m_tcs.Task
- .WaitAsync(TimeSpan.FromMilliseconds(timeout), ct);
+ _ = await WaitAsync(waitTask, timeout, ct).ConfigureAwait(false);
}
- else if (ct != default)
+ else
{
- awaitableTask = m_tcs.Task.WaitAsync(ct);
- }
- if (!await awaitableTask.ConfigureAwait(false))
- {
- badRequestInterrupted = true;
+ _ = await waitTask.ConfigureAwait(false);
}
}
catch (TimeoutException)
@@ -271,12 +280,9 @@ public async Task EndAsync(
{
badRequestInterrupted = true;
}
- finally
+ catch (OperationCanceledException)
{
- lock (m_lock)
- {
- m_tcs = null;
- }
+ badRequestInterrupted = true;
}
if (badRequestInterrupted && throwOnError)
@@ -368,17 +374,6 @@ public bool IsCompleted
}
}
- ///
- /// Called when the operation times out.
- ///
- private void OnTimeout(object? state)
- {
- if (m_timer != null)
- {
- InternalComplete(false, new ServiceResult(StatusCodes.BadRequestTimeout));
- }
- }
-
///
/// Called when an asynchronous operation completes.
///
@@ -403,12 +398,17 @@ protected virtual bool InternalComplete(bool doNotBlock, object? result)
m_completed = true;
- m_timer?.Dispose();
- m_timer = null;
+ m_timeoutCancellationRegistration.Dispose();
+ m_timeoutCancellationTokenSource?.Dispose();
+ m_timeoutCancellationTokenSource = null;
m_event?.Set();
- m_tcs?.TrySetResult(true);
+ if (m_asyncWaitPending)
+ {
+ m_asyncWaitSource.SetResult(true);
+ m_asyncWaitPending = false;
+ }
}
AsyncCallback? callback = m_callback;
@@ -436,17 +436,102 @@ protected virtual bool InternalComplete(bool doNotBlock, object? result)
return true;
}
+ ValueTaskSourceStatus IValueTaskSource.GetStatus(short token)
+ {
+ return m_asyncWaitSource.GetStatus(token);
+ }
+
+ ValueTaskSourceStatus IValueTaskSource.GetStatus(short token)
+ {
+ return m_asyncWaitSource.GetStatus(token);
+ }
+
+ bool IValueTaskSource.GetResult(short token)
+ {
+ return m_asyncWaitSource.GetResult(token);
+ }
+
+ void IValueTaskSource.GetResult(short token)
+ {
+ ((IValueTaskSource)m_asyncWaitSource).GetResult(token);
+ }
+
+ void IValueTaskSource.OnCompleted(
+ Action continuation,
+ object? state,
+ short token,
+ ValueTaskSourceOnCompletedFlags flags)
+ {
+ m_asyncWaitSource.OnCompleted(continuation, state, token, flags);
+ }
+
+ void IValueTaskSource.OnCompleted(
+ Action continuation,
+ object? state,
+ short token,
+ ValueTaskSourceOnCompletedFlags flags)
+ {
+ m_asyncWaitSource.OnCompleted(continuation, state, token, flags);
+ }
+
+ private void OnTimeout()
+ {
+ if (m_timeoutCancellationTokenSource != null)
+ {
+ InternalComplete(false, new ServiceResult(StatusCodes.BadRequestTimeout));
+ }
+ }
+
+ private static async Task WaitAsync(ValueTask waitTask, int timeout, CancellationToken ct)
+ {
+ Task task = waitTask.AsTask();
+ using CancellationTokenSource? timeoutCancellationTokenSource =
+ timeout != int.MaxValue ? new CancellationTokenSource(timeout) : null;
+ using CancellationTokenSource? linkedCancellationTokenSource =
+ timeoutCancellationTokenSource != null && ct != default ?
+ CancellationTokenSource.CreateLinkedTokenSource(ct, timeoutCancellationTokenSource.Token) :
+ null;
+
+ CancellationToken effectiveCancellationToken =
+ linkedCancellationTokenSource?.Token ??
+ timeoutCancellationTokenSource?.Token ??
+ ct;
+
+ if (!effectiveCancellationToken.CanBeCanceled)
+ {
+ _ = await task.ConfigureAwait(false);
+ return;
+ }
+
+#if NET6_0_OR_GREATER
+ _ = await task.WaitAsync(effectiveCancellationToken).ConfigureAwait(false);
+#else
+ Task completedTask = await Task.WhenAny(
+ task,
+ Task.Delay(Timeout.Infinite, effectiveCancellationToken)).ConfigureAwait(false);
+
+ if (!ReferenceEquals(completedTask, task))
+ {
+ effectiveCancellationToken.ThrowIfCancellationRequested();
+ }
+
+ _ = await task.ConfigureAwait(false);
+#endif
+ }
+
private readonly Lock m_lock = new();
private readonly AsyncCallback? m_callback;
private readonly object? m_asyncState;
private readonly bool m_synchronous;
private readonly ILogger m_logger;
+ private readonly ManualResetValueTaskSource m_asyncWaitSource = new();
private bool m_completed;
+ private bool m_asyncWaitPending;
private ManualResetEvent? m_event;
- private TaskCompletionSource? m_tcs;
private T? m_response;
private ServiceResult? m_error;
- private Timer? m_timer;
+ private CancellationTokenSource? m_timeoutCancellationTokenSource;
+ private CancellationTokenRegistration m_timeoutCancellationRegistration;
private Dictionary? m_properties;
}
}
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
index d538aff9b0..a85242eae4 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
@@ -225,7 +225,7 @@ public async ValueTask ConnectAsync(Uri url, int timeout, CancellationToken ct)
CompleteConnect(operation);
}
- await operation.EndAsync(int.MaxValue, ct: ct).ConfigureAwait(false);
+ await operation.EndValueTaskAsync(int.MaxValue, ct: ct).ConfigureAwait(false);
SendQueuedOperations();
}
@@ -264,7 +264,7 @@ public async Task CloseAsync(int timeout, CancellationToken ct = default)
{
try
{
- _ = await operation.EndAsync(timeout, false, ct).ConfigureAwait(false);
+ _ = await operation.EndValueTaskAsync(timeout, false, ct).ConfigureAwait(false);
ValidateChannelCloseError(operation.Error);
}
catch (Exception e)
@@ -334,7 +334,7 @@ public async ValueTask SendRequestAsync(
}
try
{
- await operation.EndAsync(int.MaxValue, true, ct).ConfigureAwait(false);
+ await operation.EndValueTaskAsync(int.MaxValue, true, ct).ConfigureAwait(false);
}
finally
{
@@ -1086,7 +1086,7 @@ private async void OnScheduledHandshakeAsync(object? state)
CompleteConnect(operation);
// Complete handshake
- await operation.EndAsync(int.MaxValue).ConfigureAwait(false);
+ await operation.EndValueTaskAsync(int.MaxValue).ConfigureAwait(false);
SendQueuedOperations();
}
diff --git a/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs b/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
new file mode 100644
index 0000000000..83b46e4834
--- /dev/null
+++ b/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
@@ -0,0 +1,103 @@
+/* ========================================================================
+ * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
+ *
+ * OPC Foundation MIT License 1.00
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The complete license agreement can be found here:
+ * http://opcfoundation.org/License/MIT/1.00/
+ * ======================================================================*/
+
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging.Abstractions;
+using NUnit.Framework;
+using Opc.Ua.Bindings;
+
+namespace Opc.Ua.Core.Tests.Stack.Transport
+{
+ [TestFixture]
+ [Category("TransportChannelTests")]
+ [SetCulture("en-us")]
+ [SetUICulture("en-us")]
+ [Parallelizable]
+ public sealed class ChannelAsyncOperationTests
+ {
+ [Test]
+ public async Task EndAsyncReturnsCompletedResponse()
+ {
+ using var operation = new ChannelAsyncOperation(
+ int.MaxValue,
+ null,
+ null,
+ NullLogger.Instance);
+
+ _ = Task.Run(async () =>
+ {
+ await Task.Delay(50).ConfigureAwait(false);
+ operation.Complete(123);
+ });
+
+ int result = await operation.EndAsync(int.MaxValue).ConfigureAwait(false);
+
+ Assert.That(result, Is.EqualTo(123));
+ Assert.That(operation.Error.StatusCode, Is.EqualTo(StatusCodes.Good));
+ }
+
+ [Test]
+ public void EndAsyncThrowsBadRequestInterruptedWhenCanceled()
+ {
+ using var operation = new ChannelAsyncOperation(
+ int.MaxValue,
+ null,
+ null,
+ NullLogger.Instance);
+ using var cancellationTokenSource = new CancellationTokenSource();
+
+ Task task = operation.EndAsync(int.MaxValue, ct: cancellationTokenSource.Token);
+ cancellationTokenSource.Cancel();
+
+ Assert.That(
+ async () => await task.ConfigureAwait(false),
+ Throws.TypeOf()
+ .With.Property(nameof(ServiceResultException.StatusCode))
+ .EqualTo(StatusCodes.BadRequestInterrupted));
+ }
+
+ [Test]
+ public void EndAsyncThrowsBadRequestTimeoutWhenOperationTimesOut()
+ {
+ using var operation = new ChannelAsyncOperation(
+ 50,
+ null,
+ null,
+ NullLogger.Instance);
+
+ Assert.That(
+ async () => await operation.EndAsync(int.MaxValue).ConfigureAwait(false),
+ Throws.TypeOf()
+ .With.Property(nameof(ServiceResultException.StatusCode))
+ .EqualTo(StatusCodes.BadRequestTimeout));
+ }
+ }
+}
From 689b5e27810f625699cd3687a3db28940f6e86bd Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 10:07:24 +0000
Subject: [PATCH 2/5] Validate ChannelAsyncOperation changes
Agent-Logs-Url: https://github.com/OPCFoundation/UA-.NETStandard/sessions/24828edb-ccf0-41cb-b93d-218f7111aff6
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
---
.../Stack/Tcp/ChannelAsyncOperation.cs | 2 +-
.../Transport/ChannelAsyncOperationTests.cs | 18 ++++++++----------
2 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
index 89ecc474db..e46b2377b4 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
@@ -265,7 +265,7 @@ internal async ValueTask EndValueTaskAsync(
{
if (timeout != int.MaxValue || ct != default)
{
- _ = await WaitAsync(waitTask, timeout, ct).ConfigureAwait(false);
+ await WaitAsync(waitTask, timeout, ct).ConfigureAwait(false);
}
else
{
diff --git a/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs b/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
index 83b46e4834..82bcf750d8 100644
--- a/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
+++ b/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
@@ -77,11 +77,10 @@ public void EndAsyncThrowsBadRequestInterruptedWhenCanceled()
Task task = operation.EndAsync(int.MaxValue, ct: cancellationTokenSource.Token);
cancellationTokenSource.Cancel();
- Assert.That(
- async () => await task.ConfigureAwait(false),
- Throws.TypeOf()
- .With.Property(nameof(ServiceResultException.StatusCode))
- .EqualTo(StatusCodes.BadRequestInterrupted));
+ ServiceResultException exception =
+ Assert.ThrowsAsync(() => task);
+
+ Assert.That(exception.StatusCode, Is.EqualTo(StatusCodes.BadRequestInterrupted));
}
[Test]
@@ -93,11 +92,10 @@ public void EndAsyncThrowsBadRequestTimeoutWhenOperationTimesOut()
null,
NullLogger.Instance);
- Assert.That(
- async () => await operation.EndAsync(int.MaxValue).ConfigureAwait(false),
- Throws.TypeOf()
- .With.Property(nameof(ServiceResultException.StatusCode))
- .EqualTo(StatusCodes.BadRequestTimeout));
+ ServiceResultException exception =
+ Assert.ThrowsAsync(() => operation.EndAsync(int.MaxValue));
+
+ Assert.That(exception.StatusCode, Is.EqualTo(StatusCodes.BadRequestTimeout));
}
}
}
From d829c76efd42f70765f675c68f0ec61c74ccfd9a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 10:08:22 +0000
Subject: [PATCH 3/5] Refine cancellation handling clarity
Agent-Logs-Url: https://github.com/OPCFoundation/UA-.NETStandard/sessions/24828edb-ccf0-41cb-b93d-218f7111aff6
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
---
Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
index e46b2377b4..7c369c653f 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
@@ -263,7 +263,7 @@ internal async ValueTask EndValueTaskAsync(
bool badRequestInterrupted = false;
try
{
- if (timeout != int.MaxValue || ct != default)
+ if (timeout != int.MaxValue || ct.CanBeCanceled)
{
await WaitAsync(waitTask, timeout, ct).ConfigureAwait(false);
}
@@ -488,7 +488,7 @@ private static async Task WaitAsync(ValueTask waitTask, int timeout, Cance
using CancellationTokenSource? timeoutCancellationTokenSource =
timeout != int.MaxValue ? new CancellationTokenSource(timeout) : null;
using CancellationTokenSource? linkedCancellationTokenSource =
- timeoutCancellationTokenSource != null && ct != default ?
+ timeoutCancellationTokenSource != null && ct.CanBeCanceled ?
CancellationTokenSource.CreateLinkedTokenSource(ct, timeoutCancellationTokenSource.Token) :
null;
From 5f768a2920b6a507ee09e0f0dc8d2658e5a8f7af Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 10:10:51 +0000
Subject: [PATCH 4/5] Tighten review feedback fixes
Agent-Logs-Url: https://github.com/OPCFoundation/UA-.NETStandard/sessions/24828edb-ccf0-41cb-b93d-218f7111aff6
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
---
Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs | 8 ++++----
.../Stack/Transport/ChannelAsyncOperationTests.cs | 3 ++-
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
index 7c369c653f..687cbbf3b2 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelAsyncOperation.cs
@@ -57,9 +57,8 @@ public ChannelAsyncOperation(int timeout, AsyncCallback? callback, object? async
if (timeout is > 0 and not int.MaxValue)
{
m_timeoutCancellationTokenSource = new CancellationTokenSource(timeout);
- m_timeoutCancellationRegistration = m_timeoutCancellationTokenSource.Token.Register(
- static state => ((ChannelAsyncOperation)state!).OnTimeout(),
- this);
+ m_timeoutCancellationRegistration =
+ m_timeoutCancellationTokenSource.Token.Register(OnTimeout);
}
}
@@ -94,7 +93,8 @@ protected virtual void Dispose(bool disposing)
if (m_asyncWaitPending)
{
- m_asyncWaitSource.SetException(new TaskCanceledException());
+ m_asyncWaitSource.SetException(
+ new TaskCanceledException("ChannelAsyncOperation was disposed while an async wait was pending."));
m_asyncWaitPending = false;
}
}
diff --git a/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs b/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
index 82bcf750d8..c3615e0ec8 100644
--- a/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
+++ b/Tests/Opc.Ua.Core.Tests/Stack/Transport/ChannelAsyncOperationTests.cs
@@ -52,13 +52,14 @@ public async Task EndAsyncReturnsCompletedResponse()
null,
NullLogger.Instance);
- _ = Task.Run(async () =>
+ Task completeTask = Task.Run(async () =>
{
await Task.Delay(50).ConfigureAwait(false);
operation.Complete(123);
});
int result = await operation.EndAsync(int.MaxValue).ConfigureAwait(false);
+ await completeTask.ConfigureAwait(false);
Assert.That(result, Is.EqualTo(123));
Assert.That(operation.Error.StatusCode, Is.EqualTo(StatusCodes.Good));
From 10f7f7ff08873f883bb6406b96c9c7c28db672d9 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 12:33:39 +0000
Subject: [PATCH 5/5] feat: replace socket read/write mechanics with
ValueTask-based async I/O
- IMessageSocket: remove bool Send(IMessageSocketAsyncEventArgs),
ReadNextMessage(), and MessageSocketEventArgs(); add ValueTask SendAsync
overloads and Task ReadNextMessageAsync(CancellationToken)
- TcpMessageSocket: replace SocketAsyncEventArgs state-machine with a
clean async receive loop (ReadNextMessageAsync/ReceiveExactAsync/
ReceiveAsync) and ValueTask send path (SendAsync/SendAllAsync/
SendOnceAsync). Modern path uses Socket.ReceiveAsync(Memory)
and Socket.SendAsync(ReadOnlyMemory); .NET Framework path wraps
SocketAsyncEventArgs in TaskCompletionSource.
- UaSCBinaryChannel: replace BeginWriteMessage + OnWriteComplete with
BeginWriteMessage that fires-and-forgets a ValueTask send and handles
completion via CompleteWriteAsync continuation helper
- TcpListenerChannel, TcpServerChannel, UaSCBinaryClientChannel: update
ReadNextMessage() call sites to ReadNextMessageAsync() (fire-and-forget)"
Agent-Logs-Url: https://github.com/OPCFoundation/UA-.NETStandard/sessions/2b878f3d-1010-4e94-8f65-400556548045
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
---
.../Stack/Tcp/TcpListenerChannel.cs | 2 +-
.../Opc.Ua.Core/Stack/Tcp/TcpMessageSocket.cs | 551 ++++++++++--------
.../Opc.Ua.Core/Stack/Tcp/TcpServerChannel.cs | 2 +-
.../Stack/Tcp/UaSCBinaryChannel.cs | 162 +++--
.../Stack/Tcp/UaSCBinaryClientChannel.cs | 2 +-
.../Stack/Transport/IMessageSocket.cs | 19 +-
6 files changed, 383 insertions(+), 355 deletions(-)
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/TcpListenerChannel.cs b/Stack/Opc.Ua.Core/Stack/Tcp/TcpListenerChannel.cs
index c17dc5719c..275f0dee8a 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/TcpListenerChannel.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/TcpListenerChannel.cs
@@ -161,7 +161,7 @@ public void Attach(uint channelId, Socket socket)
Socket.Handle,
ChannelId);
- Socket.ReadNextMessage();
+ Socket.ReadNextMessageAsync();
}
}
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/TcpMessageSocket.cs b/Stack/Opc.Ua.Core/Stack/Tcp/TcpMessageSocket.cs
index 2d6948968b..8a50963d82 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/TcpMessageSocket.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/TcpMessageSocket.cs
@@ -28,7 +28,7 @@
* ======================================================================*/
using System;
-using System.Diagnostics;
+using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
@@ -224,9 +224,6 @@ public TcpMessageSocket(
m_bufferManager = bufferManager ??
throw new ArgumentNullException(nameof(bufferManager));
m_receiveBufferSize = receiveBufferSize;
- m_incomingMessageSize = -1;
- m_readComplete = OnReadComplete;
- m_readState = ReadState.Ready;
}
///
@@ -245,8 +242,6 @@ public TcpMessageSocket(
m_bufferManager = bufferManager ??
throw new ArgumentNullException(nameof(bufferManager));
m_receiveBufferSize = receiveBufferSize;
- m_incomingMessageSize = -1;
- m_readComplete = OnReadComplete;
}
///
@@ -380,326 +375,388 @@ public void Close()
///
/// Starts reading messages from the socket.
///
- public void ReadNextMessage()
+ public async Task ReadNextMessageAsync(CancellationToken ct = default)
{
- lock (m_readLock)
+ byte[]? receiveBuffer = null;
+ try
{
- do
+ while (true)
{
- // allocate a buffer large enough to a message chunk.
- m_receiveBuffer ??= m_bufferManager.TakeBuffer(
+ receiveBuffer = m_bufferManager.TakeBuffer(
m_receiveBufferSize,
- "ReadNextMessage");
+ "ReadNextMessageAsync");
+
+ // Read the fixed-size message header (type + size = 8 bytes).
+ int headerRead = await ReceiveExactAsync(
+ receiveBuffer,
+ 0,
+ TcpMessageLimits.MessageTypeAndSize,
+ ct).ConfigureAwait(false);
+
+ if (headerRead == 0)
+ {
+ m_bufferManager.ReturnBuffer(receiveBuffer, "ReadNextMessageAsync");
+ receiveBuffer = null;
+ m_sink?.OnReceiveError(this,
+ ServiceResult.Create(
+ StatusCodes.BadConnectionClosed,
+ "Remote side closed connection."));
+ return;
+ }
+
+ // Validate the message type.
+ uint messageType = BitConverter.ToUInt32(receiveBuffer, 0);
+ if (!TcpMessageType.IsValid(messageType))
+ {
+ m_bufferManager.ReturnBuffer(receiveBuffer, "ReadNextMessageAsync");
+ receiveBuffer = null;
+ m_sink?.OnReceiveError(this,
+ ServiceResult.Create(
+ StatusCodes.BadTcpMessageTypeInvalid,
+ "Message type {0:X8} is invalid.",
+ messageType));
+ return;
+ }
+
+ // Validate the declared message size.
+ int messageSize = BitConverter.ToInt32(receiveBuffer, 4);
+ if (messageSize <= 0 || messageSize > m_receiveBufferSize)
+ {
+ m_bufferManager.ReturnBuffer(receiveBuffer, "ReadNextMessageAsync");
+ receiveBuffer = null;
+ m_sink?.OnReceiveError(this,
+ ServiceResult.Create(
+ StatusCodes.BadTcpMessageTooLarge,
+ "Messages size {0} bytes is too large for buffer of size {1}.",
+ messageSize,
+ m_receiveBufferSize));
+ return;
+ }
+
+ // Read the remainder of the message body.
+ int remaining = messageSize - TcpMessageLimits.MessageTypeAndSize;
+ if (remaining > 0)
+ {
+ int bodyRead = await ReceiveExactAsync(
+ receiveBuffer,
+ TcpMessageLimits.MessageTypeAndSize,
+ remaining,
+ ct).ConfigureAwait(false);
- // read the first 8 bytes of the message which contains the message size.
- m_bytesReceived = 0;
- m_bytesToReceive = TcpMessageLimits.MessageTypeAndSize;
- m_incomingMessageSize = -1;
+ if (bodyRead == 0)
+ {
+ m_bufferManager.ReturnBuffer(receiveBuffer, "ReadNextMessageAsync");
+ receiveBuffer = null;
+ m_sink?.OnReceiveError(this,
+ ServiceResult.Create(
+ StatusCodes.BadConnectionClosed,
+ "Remote side closed connection."));
+ return;
+ }
+ }
- do
+ // Deliver the complete message chunk to the sink.
+ IMessageSink? sink = m_sink;
+ if (sink != null)
+ {
+ var messageChunk = new ArraySegment(receiveBuffer, 0, messageSize);
+ receiveBuffer = null; // sink now owns the buffer
+ try
+ {
+ sink.OnMessageReceived(this, messageChunk);
+ }
+ catch (Exception ex)
+ {
+ m_logger.LogError(
+ ex,
+ "Unexpected error invoking OnMessageReceived callback.");
+ }
+ }
+ else
{
- ReadNextBlock();
- } while (m_readState == ReadState.ReadNextBlock);
- } while (m_readState == ReadState.ReadNextMessage);
+ m_bufferManager.ReturnBuffer(receiveBuffer, "ReadNextMessageAsync");
+ receiveBuffer = null;
+ }
+ }
+ }
+ catch (OperationCanceledException) when (ct.IsCancellationRequested)
+ {
+ // Normal cancellation - loop exits silently.
+ }
+ catch (Exception ex)
+ {
+ m_sink?.OnReceiveError(this,
+ ServiceResult.Create(
+ ex,
+ StatusCodes.BadTcpInternalError,
+ "Unexpected error receiving data."));
+ }
+ finally
+ {
+ if (receiveBuffer != null)
+ {
+ m_bufferManager.ReturnBuffer(receiveBuffer, "ReadNextMessageAsync");
+ }
}
}
///
- /// Changes the sink used to report reads.
+ /// Reads exactly bytes starting at
+ /// in .
+ /// Returns 0 if the remote side closed the connection before any bytes were read.
///
- public void ChangeSink(IMessageSink sink)
+ private async Task ReceiveExactAsync(
+ byte[] buffer,
+ int offset,
+ int count,
+ CancellationToken ct)
{
- lock (m_readLock)
+ int totalReceived = 0;
+ while (totalReceived < count)
{
- m_sink = sink;
+ int received = await ReceiveAsync(
+ buffer,
+ offset + totalReceived,
+ count - totalReceived,
+ ct).ConfigureAwait(false);
+
+ if (received == 0)
+ {
+ // Connection closed without sending all bytes.
+ return 0;
+ }
+
+ totalReceived += received;
}
+
+ return totalReceived;
}
+#if NETFRAMEWORK
///
- /// Handles a read complete event.
+ /// Single async receive call wrapped in a Task (legacy .NET Framework path).
///
- private void OnReadComplete(object? sender, SocketAsyncEventArgs e)
+ private Task ReceiveAsync(byte[] buffer, int offset, int count, CancellationToken ct)
{
- lock (m_readLock)
+ Socket? socket;
+ lock (m_socketLock)
{
- ServiceResult? error = null;
+ socket = m_socket;
+ }
- try
- {
- bool innerCall = m_readState == ReadState.ReadComplete;
- error = DoReadComplete(e);
- // to avoid recursion, inner calls of OnReadComplete return
- // after processing the ReadComplete and let the outer call handle it
- if (!innerCall && !ServiceResult.IsBad(error))
- {
- while (ReadNext())
- {
- }
- }
- }
- catch (Exception ex)
+ if (socket == null || !socket.Connected)
+ {
+ return Task.FromResult(0);
+ }
+
+ var tcs = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+ var args = new SocketAsyncEventArgs();
+ args.SetBuffer(buffer, offset, count);
+ CancellationTokenRegistration registration = ct.Register(
+ static state => ((TaskCompletionSource)state!).TrySetCanceled(),
+ tcs);
+
+ args.Completed += (_, e) =>
+ {
+ registration.Dispose();
+ if (e.SocketError != SocketError.Success)
{
- m_logger.LogError(ex, "Unexpected error during OnReadComplete,");
- error = ServiceResult.Create(ex, StatusCodes.BadTcpInternalError, ex.Message);
+ tcs.TrySetException(new SocketException((int)e.SocketError));
}
- finally
+ else
{
- e?.Dispose();
+ tcs.TrySetResult(e.BytesTransferred);
}
- if (m_readState == ReadState.NotConnected && ServiceResult.IsGood(error))
- {
- error = ServiceResult.Create(
- StatusCodes.BadConnectionClosed,
- "Remote side closed connection.");
- }
+ e.Dispose();
+ };
- if (ServiceResult.IsBad(error))
+ try
+ {
+ if (!socket.ReceiveAsync(args))
{
- if (m_receiveBuffer != null)
+ // Completed synchronously.
+ registration.Dispose();
+ SocketError socketError = args.SocketError;
+ int bytesTransferred = args.BytesTransferred;
+ args.Dispose();
+
+ if (socketError != SocketError.Success)
{
- m_bufferManager.ReturnBuffer(m_receiveBuffer, "OnReadComplete");
- m_receiveBuffer = null;
+ return Task.FromException(new SocketException((int)socketError));
}
- m_sink?.OnReceiveError(this, error);
+ return Task.FromResult(bytesTransferred);
}
}
- }
+ catch (Exception ex)
+ {
+ registration.Dispose();
+ args.Dispose();
+ return Task.FromException(ex);
+ }
+ return tcs.Task;
+ }
+#else
///
- /// Handles a read complete event.
+ /// Single async receive call using the modern API.
///
- private ServiceResult DoReadComplete(SocketAsyncEventArgs e)
+ private ValueTask ReceiveAsync(byte[] buffer, int offset, int count, CancellationToken ct)
{
- // complete operation.
- int bytesRead = e.BytesTransferred;
- m_readState = ReadState.Ready;
-
+ Socket? socket;
lock (m_socketLock)
{
- if (m_receiveBuffer != null)
- {
- BufferManager.UnlockBuffer(m_receiveBuffer);
- }
+ socket = m_socket;
}
- if (bytesRead == 0)
+ if (socket == null || !socket.Connected)
{
- // Remote end has closed the connection
+ return new ValueTask(0);
+ }
- // free the empty receive buffer.
- if (m_receiveBuffer != null)
- {
- m_bufferManager.ReturnBuffer(m_receiveBuffer, "DoReadComplete");
- m_receiveBuffer = null;
- }
+ return socket.ReceiveAsync(buffer.AsMemory(offset, count), SocketFlags.None, ct);
+ }
+#endif
+
+ ///
+ /// Changes the sink used to report reads.
+ ///
+ public void ChangeSink(IMessageSink sink)
+ {
+ m_sink = sink;
+ }
- m_readState = ReadState.Error;
- return ServiceResult.Create(
- StatusCodes.BadConnectionClosed,
- "Remote side closed connection");
+ ///
+ public ValueTask SendAsync(ReadOnlyMemory buffer, CancellationToken ct = default)
+ {
+ if (m_socket == null)
+ {
+ throw new InvalidOperationException("The socket is not connected.");
}
- m_bytesReceived += bytesRead;
+ return SendAllAsync(buffer, ct);
+ }
- // check if more data left to read.
- if (m_bytesReceived < m_bytesToReceive)
+ ///
+ public ValueTask SendAsync(IList> buffers, CancellationToken ct = default)
+ {
+ if (m_socket == null)
{
- m_readState = ReadState.ReadNextBlock;
- return ServiceResult.Good;
+ throw new InvalidOperationException("The socket is not connected.");
}
- // start reading the message body.
- if (m_receiveBuffer != null)
+ return SendBufferListAsync(buffers, ct);
+ }
+
+ private async ValueTask SendAllAsync(ReadOnlyMemory data, CancellationToken ct)
+ {
+ while (data.Length > 0)
{
- if (m_incomingMessageSize < 0)
+ int sent = await SendOnceAsync(data, ct).ConfigureAwait(false);
+ if (sent == 0)
{
- uint messageType = BitConverter.ToUInt32(m_receiveBuffer, 0);
- if (!TcpMessageType.IsValid(messageType))
- {
- m_readState = ReadState.Error;
-
- return ServiceResult.Create(
- StatusCodes.BadTcpMessageTypeInvalid,
- "Message type {0:X8} is invalid.",
- messageType);
- }
-
- m_incomingMessageSize = BitConverter.ToInt32(m_receiveBuffer, 4);
- if (m_incomingMessageSize <= 0 || m_incomingMessageSize > m_receiveBufferSize)
- {
- m_readState = ReadState.Error;
-
- return ServiceResult.Create(
- StatusCodes.BadTcpMessageTooLarge,
- "Messages size {0} bytes is too large for buffer of size {1}.",
- m_incomingMessageSize,
- m_receiveBufferSize);
- }
-
- // set up buffer for reading the message body.
- m_bytesToReceive = m_incomingMessageSize;
-
- m_readState = ReadState.ReadNextBlock;
-
- return ServiceResult.Good;
+ throw new SocketException((int)SocketError.ConnectionReset);
}
- // notify the sink.
- IMessageSink sink = m_sink;
- if (sink != null)
- {
- try
- {
- // send notification (implementor responsible for freeing buffer) on success.
- var messageChunk = new ArraySegment(
- m_receiveBuffer,
- 0,
- m_incomingMessageSize);
-
- // must allocate a new buffer for the next message.
- m_receiveBuffer = null;
-
- sink.OnMessageReceived(this, messageChunk);
- }
- catch (Exception ex)
- {
- m_logger.LogError(ex, "Unexpected error invoking OnMessageReceived callback.");
- }
- }
+ data = data.Slice(sent);
}
+ }
- // free the receive buffer.
- if (m_receiveBuffer != null)
+ private async ValueTask SendBufferListAsync(IList> buffers, CancellationToken ct)
+ {
+ foreach (ArraySegment segment in buffers)
{
- m_bufferManager.ReturnBuffer(m_receiveBuffer, "DoReadComplete");
- m_receiveBuffer = null;
+ await SendAllAsync(
+ new ReadOnlyMemory(segment.Array, segment.Offset, segment.Count),
+ ct).ConfigureAwait(false);
}
-
- // start receiving next message.
- m_readState = ReadState.ReadNextMessage;
-
- return ServiceResult.Good;
}
- ///
- /// Reads the next block of data from the socket.
- ///
- private void ReadNextBlock()
+#if NETFRAMEWORK
+ private Task SendOnceAsync(ReadOnlyMemory data, CancellationToken ct)
{
Socket? socket;
-
- // check if already closed.
lock (m_socketLock)
{
socket = m_socket;
+ }
+
+ if (socket == null)
+ {
+ return Task.FromResult(0);
+ }
+
+ if (!MemoryMarshal.TryGetArray(data, out ArraySegment segment))
+ {
+ segment = new ArraySegment(data.ToArray());
+ }
+
+ var tcs = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+ var args = new SocketAsyncEventArgs();
+ args.SetBuffer(segment.Array, segment.Offset, segment.Count);
+ CancellationTokenRegistration registration = ct.Register(
+ static state => ((TaskCompletionSource)state!).TrySetCanceled(),
+ tcs);
- if (socket == null || !socket.Connected)
+ args.Completed += (_, e) =>
+ {
+ registration.Dispose();
+ if (e.SocketError != SocketError.Success)
{
- // buffer is returned in calling code
- m_readState = ReadState.NotConnected;
- return;
+ tcs.TrySetException(new SocketException((int)e.SocketError));
+ }
+ else
+ {
+ tcs.TrySetResult(e.BytesTransferred);
}
- }
- BufferManager.LockBuffer(m_receiveBuffer!);
+ e.Dispose();
+ };
- SocketAsyncEventArgs? args = null;
try
{
- args = new SocketAsyncEventArgs();
- m_readState = ReadState.Receive;
- args.SetBuffer(
- m_receiveBuffer,
- m_bytesReceived,
- m_bytesToReceive - m_bytesReceived);
- args.Completed += m_readComplete;
- if (!socket.ReceiveAsync(args))
+ if (!socket.SendAsync(args))
{
- // I/O completed synchronously
- if (args.SocketError != SocketError.Success)
+ registration.Dispose();
+ SocketError socketError = args.SocketError;
+ int bytesTransferred = args.BytesTransferred;
+ args.Dispose();
+
+ if (socketError != SocketError.Success)
{
- throw ServiceResultException.Create(
- StatusCodes.BadTcpInternalError,
- args.SocketError.ToString());
+ return Task.FromException(new SocketException((int)socketError));
}
- // set state to inner complete
- m_readState = ReadState.ReadComplete;
- m_readComplete(null, args);
+
+ return Task.FromResult(bytesTransferred);
}
- args = null; // ownership transferred
- }
- catch (ServiceResultException)
- {
- BufferManager.UnlockBuffer(m_receiveBuffer!);
- throw;
}
catch (Exception ex)
{
- BufferManager.UnlockBuffer(m_receiveBuffer!);
- throw ServiceResultException.Create(
- StatusCodes.BadTcpInternalError,
- ex,
- "BeginReceive failed.");
+ registration.Dispose();
+ args.Dispose();
+ return Task.FromException(ex);
}
- finally
- {
- args?.Dispose();
- }
- }
- ///
- /// Helper to read next block or message based on current state.
- ///
- private bool ReadNext()
- {
- switch (m_readState)
- {
- case ReadState.ReadNextBlock:
- ReadNextBlock();
- return true;
- case ReadState.ReadNextMessage:
- ReadNextMessage();
- return true;
- case ReadState.Ready:
- case ReadState.Receive:
- case ReadState.ReadComplete:
- case ReadState.NotConnected:
- case ReadState.Error:
- return false;
- default:
- Debug.Fail("Unexpected read state.");
- return false;
- }
+ return tcs.Task;
}
-
- ///
- /// Sends a buffer.
- ///
- ///
- ///
- public bool Send(IMessageSocketAsyncEventArgs args)
+#else
+ private ValueTask SendOnceAsync(ReadOnlyMemory data, CancellationToken ct)
{
- if (args is not TcpMessageSocketAsyncEventArgs eventArgs)
+ Socket? socket;
+ lock (m_socketLock)
{
- throw new ArgumentNullException(nameof(args));
+ socket = m_socket;
}
- if (m_socket == null)
+
+ if (socket == null)
{
- throw new InvalidOperationException("The socket is not connected.");
+ return new ValueTask(0);
}
- eventArgs.Args.SocketError = SocketError.NotConnected;
- return m_socket.SendAsync(eventArgs.Args);
- }
- ///
- /// Create event args for TcpMessageSocket.
- ///
- public IMessageSocketAsyncEventArgs MessageSocketEventArgs()
- {
- return new TcpMessageSocketAsyncEventArgs();
+ return socket.SendAsync(data, SocketFlags.None, ct);
}
+#endif
private void ShutdownAndDispose(Socket socket)
{
@@ -725,31 +782,9 @@ private void ShutdownAndDispose(Socket socket)
private readonly ILogger m_logger;
private readonly BufferManager m_bufferManager;
private readonly int m_receiveBufferSize;
- private readonly EventHandler m_readComplete;
private readonly Lock m_socketLock = new();
private Socket? m_socket;
private bool m_closed;
-
- ///
- /// States for the nested read handler.
- ///
- private enum ReadState
- {
- Ready = 0,
- ReadNextMessage = 1,
- ReadNextBlock = 2,
- Receive = 3,
- ReadComplete = 4,
- NotConnected = 5,
- Error = 0xff
- }
-
- private readonly Lock m_readLock = new();
- private byte[]? m_receiveBuffer;
- private int m_bytesReceived;
- private int m_bytesToReceive;
- private int m_incomingMessageSize;
- private ReadState m_readState;
}
}
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/TcpServerChannel.cs b/Stack/Opc.Ua.Core/Stack/Tcp/TcpServerChannel.cs
index 3d76874ad7..ad7fc46c98 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/TcpServerChannel.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/TcpServerChannel.cs
@@ -192,7 +192,7 @@ private void OnReverseConnectComplete(object? sender, IMessageSocketAsyncEventAr
try
{
// start reading messages.
- ar.Socket!.ReadNextMessage();
+ ar.Socket!.ReadNextMessageAsync();
// send reverse hello message.
using var encoder = new BinaryEncoder(
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryChannel.cs b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryChannel.cs
index 31dc52dfc5..3f25020f13 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryChannel.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryChannel.cs
@@ -541,124 +541,105 @@ protected virtual void HandleSocketError(ServiceResult result)
}
///
- /// Handles a write complete event.
+ /// Queues a write request for a single contiguous buffer.
+ /// The buffer is returned to after the send completes.
///
- protected virtual void OnWriteComplete(object? sender, IMessageSocketAsyncEventArgs e)
+ ///
+ protected void BeginWriteMessage(ArraySegment buffer, object? state)
{
- ServiceResult error = ServiceResult.Good;
+ IMessageSocket socket =
+ Socket ?? throw ServiceResultException.Create(
+ StatusCodes.BadConnectionClosed,
+ "The socket was closed by the remote application.");
+
+ Interlocked.Increment(ref m_activeWriteRequests);
+ byte[] bufferArray = buffer.GetArray();
+ var data = new ReadOnlyMemory(bufferArray, buffer.Offset, buffer.Count);
+
+ ValueTask task;
try
{
- if (e.BytesTransferred == 0)
- {
- error = ServiceResult.Create(
- StatusCodes.BadConnectionClosed,
- "The socket was closed by the remote application.");
- }
- if (e.Buffer != null)
- {
- BufferManager.ReturnBuffer(e.Buffer, "OnWriteComplete");
- }
- HandleWriteComplete(e.BufferList, e.UserToken, e.BytesTransferred, error);
+ task = socket.SendAsync(data);
}
catch (Exception ex)
{
- if (ex is InvalidOperationException)
- {
- // suppress chained exception in HandleWriteComplete/ReturnBuffer
- e.BufferList = null;
- }
- error = ServiceResult.Create(
- ex,
- StatusCodes.BadTcpInternalError,
- "Unexpected error during write operation.");
- HandleWriteComplete(e.BufferList, e.UserToken, e.BytesTransferred, error);
+ BufferManager.ReturnBuffer(bufferArray, "BeginWriteMessage");
+ HandleWriteComplete(
+ null,
+ state,
+ 0,
+ ServiceResult.Create(
+ ex,
+ StatusCodes.BadTcpInternalError,
+ "Unexpected error during write operation."));
+ return;
}
- e.Dispose();
+ if (task.IsCompletedSuccessfully)
+ {
+ BufferManager.ReturnBuffer(bufferArray, "BeginWriteMessage");
+ HandleWriteComplete(null, state, buffer.Count, ServiceResult.Good);
+ return;
+ }
+
+ _ = CompleteWriteAsync(task, bufferArray, null, state, buffer.Count);
}
///
- /// Queues a write request.
+ /// Queues a write request for a collection of buffers.
+ /// The buffers are released via after the send completes.
///
- ///
- protected void BeginWriteMessage(ArraySegment buffer, object? state)
+ protected void BeginWriteMessage(BufferCollection buffers, object? state)
{
- ServiceResult error = ServiceResult.Good;
- IMessageSocketAsyncEventArgs args =
- (Socket?.MessageSocketEventArgs())
- ?? throw ServiceResultException.Create(
+ IMessageSocket socket =
+ Socket ?? throw ServiceResultException.Create(
StatusCodes.BadConnectionClosed,
"The socket was closed by the remote application.");
+ Interlocked.Increment(ref m_activeWriteRequests);
+
+ ValueTask task;
try
{
- Interlocked.Increment(ref m_activeWriteRequests);
- args.SetBuffer(buffer.GetArray(), buffer.Offset, buffer.Count);
- args.Completed += OnWriteComplete;
- args.UserToken = state;
- if (!Socket.Send(args))
- {
- // I/O completed synchronously
- if (args.IsSocketError || (args.BytesTransferred < buffer.Count))
- {
- error = ServiceResult.Create(
- StatusCodes.BadConnectionClosed,
- args.SocketErrorString);
- HandleWriteComplete(null, state, args.BytesTransferred, error);
- args.Dispose();
- }
- else
- {
- // success, call Complete
- OnWriteComplete(null, args);
- }
- }
+ task = socket.SendAsync(buffers);
}
catch (Exception ex)
{
- error = ServiceResult.Create(
- ex,
- StatusCodes.BadTcpInternalError,
- "Unexpected error during write operation.");
+ HandleWriteComplete(
+ buffers,
+ state,
+ 0,
+ ServiceResult.Create(
+ ex,
+ StatusCodes.BadTcpInternalError,
+ "Unexpected error during write operation."));
+ return;
+ }
- HandleWriteComplete(null, state, args.BytesTransferred, error);
- args.Dispose();
+ if (task.IsCompletedSuccessfully)
+ {
+ HandleWriteComplete(buffers, state, buffers.TotalSize, ServiceResult.Good);
+ return;
}
+
+ _ = CompleteWriteAsync(task, null, buffers, state, buffers.TotalSize);
}
///
- /// Queues a write request.
+ /// Awaits a pending write and then calls
+ /// with the outcome.
///
- protected void BeginWriteMessage(BufferCollection buffers, object? state)
+ private async Task CompleteWriteAsync(
+ ValueTask task,
+ byte[]? bufferToReturn,
+ BufferCollection? buffers,
+ object? state,
+ int expectedBytes)
{
ServiceResult error = ServiceResult.Good;
- IMessageSocketAsyncEventArgs args = Socket!.MessageSocketEventArgs();
-
try
{
- // m_logger.LogWarning("OUT:{Id}", TcpMessageType.GetTypeAndSize(buffers[0]));
-
- Interlocked.Increment(ref m_activeWriteRequests);
- args.BufferList = buffers;
- args.Completed += OnWriteComplete;
- args.UserToken = state;
- IMessageSocket? socket = Socket;
- if (socket == null || !socket.Send(args))
- {
- // I/O completed synchronously
- if (args.IsSocketError || (args.BytesTransferred < buffers.TotalSize))
- {
- error = ServiceResult.Create(
- StatusCodes.BadConnectionClosed,
- args.SocketErrorString);
- HandleWriteComplete(buffers, state, args.BytesTransferred, error);
- args.Dispose();
- }
- else
- {
- OnWriteComplete(null, args);
- }
- }
+ await task.ConfigureAwait(false);
}
catch (Exception ex)
{
@@ -666,9 +647,14 @@ protected void BeginWriteMessage(BufferCollection buffers, object? state)
ex,
StatusCodes.BadTcpInternalError,
"Unexpected error during write operation.");
- HandleWriteComplete(buffers, state, args.BytesTransferred, error);
- args.Dispose();
}
+
+ if (bufferToReturn != null)
+ {
+ BufferManager.ReturnBuffer(bufferToReturn, "CompleteWriteAsync");
+ }
+
+ HandleWriteComplete(buffers, state, ServiceResult.IsGood(error) ? expectedBytes : 0, error);
}
///
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
index a85242eae4..a73647d6be 100644
--- a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
+++ b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
@@ -948,7 +948,7 @@ private void CompleteConnect(WriteOperation operation)
}
// start reading messages.
- Socket.ReadNextMessage();
+ Socket.ReadNextMessageAsync();
// send the hello message.
SendHelloMessage(operation);
diff --git a/Stack/Opc.Ua.Core/Stack/Transport/IMessageSocket.cs b/Stack/Opc.Ua.Core/Stack/Transport/IMessageSocket.cs
index 256f88b3a0..9b30174964 100644
--- a/Stack/Opc.Ua.Core/Stack/Transport/IMessageSocket.cs
+++ b/Stack/Opc.Ua.Core/Stack/Transport/IMessageSocket.cs
@@ -28,6 +28,7 @@
* ======================================================================*/
using System;
+using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
@@ -191,9 +192,13 @@ public interface IMessageSocket : IDisposable
void Close();
///
- /// Starts reading messages from the socket.
+ /// Starts the async read loop that delivers complete message chunks via
+ /// until the connection is
+ /// closed or an error occurs. The returned completes
+ /// when the loop terminates; errors are reported through
+ /// before the task completes.
///
- void ReadNextMessage();
+ Task ReadNextMessageAsync(CancellationToken ct = default);
///
/// Changes the sink used to report reads.
@@ -201,14 +206,16 @@ public interface IMessageSocket : IDisposable
void ChangeSink(IMessageSink sink);
///
- /// Sends a buffer.
+ /// Sends a single contiguous buffer asynchronously.
+ /// The caller retains ownership of the underlying array; the implementation
+ /// must not access it after the returned completes.
///
- bool Send(IMessageSocketAsyncEventArgs args);
+ ValueTask SendAsync(ReadOnlyMemory buffer, CancellationToken ct = default);
///
- /// Get the message socket event args.
+ /// Sends a list of buffers as a logical gather-write asynchronously.
///
- IMessageSocketAsyncEventArgs MessageSocketEventArgs();
+ ValueTask SendAsync(IList> buffers, CancellationToken ct = default);
}
///