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Simplify LibuvConnection.OnRead() (#1828) 

* Simplify LibuvConnection.OnRead()

- Fix a null reference that sometimes occurs given an EOF status
This commit is contained in:
Stephen Halter 2017-05-15 11:02:16 -07:00 committed by GitHub
parent 01b8d5fad1
commit 41f1922502
2 changed files with 82 additions and 61 deletions
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104
src/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv/Internal/LibuvConnection.cs
View File

@ -40,11 +40,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Internal
}
}
// For testing
public LibuvConnection()
{
}
public string ConnectionId { get; set; }
public IPipeWriter Input { get; set; }
public LibuvOutputConsumer Output { get; set; }
@ -128,76 +123,72 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Internal
private void OnRead(UvStreamHandle handle, int status)
{
var normalRead = status >= 0;
var normalDone = status == LibuvConstants.EOF;
var errorDone = !(normalDone || normalRead);
var readCount = normalRead ? status : 0;
if (normalRead)
if (status == 0)
{
Log.ConnectionRead(ConnectionId, readCount);
// EAGAIN/EWOULDBLOCK so just return the buffer.
// http://docs.libuv.org/en/v1.x/stream.html#c.uv_read_cb
Debug.Assert(_currentWritableBuffer != null);
_currentWritableBuffer.Value.Commit();
}
else if (status > 0)
{
Log.ConnectionRead(ConnectionId, status);
Debug.Assert(_currentWritableBuffer != null);
var currentWritableBuffer = _currentWritableBuffer.Value;
currentWritableBuffer.Advance(status);
var flushTask = currentWritableBuffer.FlushAsync();
if (!flushTask.IsCompleted)
{
// We wrote too many bytes to the reader, so pause reading and resume when
// we hit the low water mark.
_ = ApplyBackpressureAsync(flushTask);
}
}
else
{
// Given a negative status, it's possible that OnAlloc wasn't called.
_currentWritableBuffer?.Commit();
_socket.ReadStop();
if (normalDone)
IOException error = null;
if (status == LibuvConstants.EOF)
{
Log.ConnectionReadFin(ConnectionId);
}
}
IOException error = null;
WritableBufferAwaitable? flushTask = null;
if (errorDone)
{
handle.Libuv.Check(status, out var uvError);
// Log connection resets at a lower (Debug) level.
if (status == LibuvConstants.ECONNRESET)
{
Log.ConnectionReset(ConnectionId);
error = new ConnectionResetException(uvError.Message, uvError);
}
else
{
Log.ConnectionError(ConnectionId, uvError);
error = new IOException(uvError.Message, uvError);
handle.Libuv.Check(status, out var uvError);
// Log connection resets at a lower (Debug) level.
if (status == LibuvConstants.ECONNRESET)
{
Log.ConnectionReset(ConnectionId);
error = new ConnectionResetException(uvError.Message, uvError);
}
else
{
Log.ConnectionError(ConnectionId, uvError);
error = new IOException(uvError.Message, uvError);
}
}
_currentWritableBuffer?.Commit();
}
else
{
Debug.Assert(_currentWritableBuffer != null);
var currentWritableBuffer = _currentWritableBuffer.Value;
currentWritableBuffer.Advance(readCount);
flushTask = currentWritableBuffer.FlushAsync();
}
_currentWritableBuffer = null;
_bufferHandle.Free();
if (!normalRead)
{
_connectionContext.Abort(error);
// Complete after aborting the connection
Input.Complete(error);
}
else if (flushTask?.IsCompleted == false)
{
// We wrote too many bytes too the reader so pause reading and resume when
// we hit the low water mark
_ = ApplyBackpressureAsync(flushTask.Value);
}
// Cleanup state from last OnAlloc. This is safe even if OnAlloc wasn't called.
_currentWritableBuffer = null;
_bufferHandle.Free();
}
private async Task ApplyBackpressureAsync(WritableBufferAwaitable flushTask)
{
Log.ConnectionPause(ConnectionId);
StopReading();
_socket.ReadStop();
var result = await flushTask;
@ -209,11 +200,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Internal
}
}
private void StopReading()
{
_socket.ReadStop();
}
private void StartReading()
{
try
@ -223,7 +209,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Internal
catch (UvException ex)
{
// ReadStart() can throw a UvException in some cases (e.g. socket is no longer connected).
// This should be treated the same as OnRead() seeing a "normalDone" condition.
// This should be treated the same as OnRead() seeing a negative status.
Log.ConnectionReadFin(ConnectionId);
var error = new IOException(ex.Message, ex);

39
test/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests/ConnectionTests.cs → test/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests/LibuvConnectionTests.cs
View File

@ -14,7 +14,7 @@ using Xunit;
namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests
{
public class ConnectionTests
public class LibuvConnectionTests
{
[Fact]
public async Task DoesNotEndConnectionOnZeroRead()
@ -42,7 +42,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests
mockLibuv.ReadCallback(socket.InternalGetHandle(), 0, ref ignored);
}, (object)null);
var readAwaitable = await mockConnectionHandler.Input.Reader.ReadAsync();
var readAwaitable = mockConnectionHandler.Input.Reader.ReadAsync();
Assert.False(readAwaitable.IsCompleted);
}
finally
@ -175,5 +175,40 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests
await thread.StopAsync(TimeSpan.FromSeconds(1));
}
}
[Fact]
public async Task DoesNotThrowIfOnReadCallbackCalledWithEOFButAllocCallbackNotCalled()
{
var mockConnectionHandler = new MockConnectionHandler();
var mockLibuv = new MockLibuv();
var transportContext = new TestLibuvTransportContext() { ConnectionHandler = mockConnectionHandler };
var transport = new LibuvTransport(mockLibuv, transportContext, null);
var thread = new LibuvThread(transport);
try
{
await thread.StartAsync();
await thread.PostAsync(_ =>
{
var listenerContext = new ListenerContext(transportContext)
{
Thread = thread
};
var socket = new MockSocket(mockLibuv, Thread.CurrentThread.ManagedThreadId, transportContext.Log);
var connection = new LibuvConnection(listenerContext, socket);
_ = connection.Start();
var ignored = new LibuvFunctions.uv_buf_t();
mockLibuv.ReadCallback(socket.InternalGetHandle(), TestConstants.EOF, ref ignored);
}, (object)null);
var readAwaitable = await mockConnectionHandler.Input.Reader.ReadAsync();
Assert.True(readAwaitable.IsCompleted);
}
finally
{
await thread.StopAsync(TimeSpan.FromSeconds(1));
}
}
}
}