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// Copyright (c) 2009 Sun Microsystems, Inc.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most
// MySQL Connectors. There are special exceptions to the terms and
// conditions of the GPLv2 as it is applied to this software, see the
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
using System;
using System.Net.Sockets;
internal class MyNetworkStream : NetworkStream
{
/// <summary>
/// Wrapper around NetworkStream.
///
/// MyNetworkStream is equivalent to NetworkStream, except
/// 1. It throws TimeoutException if read or write timeout occurs, instead
/// of IOException, to match behavior of other streams (named pipe and
/// shared memory). This property comes handy in TimedStream.
///
/// 2. It implements workarounds for WSAEWOULDBLOCK errors, that can start
/// occuring after stream has times out. For a discussion about the CLR bug,
/// refer to http://tinyurl.com/lhgpyf. This error should never occur, as
/// we're not using asynchronous operations, but apparerntly it does occur
/// directly after timeout has expired.
/// The workaround is hinted in the URL above and implemented like this:
/// For each IO operation, if it throws WSAEWOULDBLOCK, we explicitely set
/// the socket to Blocking and retry the operation once again.
/// </summary>
const int MaxRetryCount = 2;
Socket socket;
public MyNetworkStream(Socket socket, bool ownsSocket)
: base(socket, ownsSocket)
{
this.socket = socket;
}
bool IsTimeoutException(SocketException e)
{
#if CF
return (e.NativeErrorCode == 10060);
#else
return (e.SocketErrorCode == SocketError.TimedOut);
#endif
}
bool IsWouldBlockException(SocketException e)
{
#if CF
return (e.NativeErrorCode == 10035);
#else
return (e.SocketErrorCode == SocketError.WouldBlock);
#endif
}
void HandleOrRethrowException(Exception e)
{
Exception currentException = e;
while (currentException != null)
{
if (currentException is SocketException)
{
SocketException socketException = (SocketException)currentException;
if (IsWouldBlockException(socketException))
{
// Workaround for WSAEWOULDBLOCK
socket.Blocking= true;
// return to give the caller possibility to retry the call
return;
}
else if (IsTimeoutException(socketException))
{
throw new TimeoutException(socketException.Message, e);
}
}
currentException = currentException.InnerException;
}
throw (e);
}
public override int Read(byte[] buffer, int offset, int count)
{
int retry = 0;
Exception exception = null;
do
{
try
{
return base.Read(buffer, offset, count);
}
catch (Exception e)
{
exception = e;
HandleOrRethrowException(e);
}
}
while (++retry < MaxRetryCount);
throw exception;
}
public override int ReadByte()
{
int retry = 0;
Exception exception = null;
do
{
try
{
return base.ReadByte();
}
catch (Exception e)
{
exception = e;
HandleOrRethrowException(e);
}
}
while (++retry < MaxRetryCount);
throw exception;
}
public override void Write(byte[] buffer, int offset, int count)
{
int retry = 0;
Exception exception = null;
do
{
try
{
base.Write(buffer, offset, count);
return;
}
catch (Exception e)
{
exception = e;
HandleOrRethrowException(e);
}
}
while (++retry < MaxRetryCount);
throw exception;
}
public override void Flush()
{
int retry = 0;
Exception exception = null;
do
{
try
{
base.Flush();
return;
}
catch (Exception e)
{
exception = e;
HandleOrRethrowException(e);
}
}
while (++retry < MaxRetryCount);
throw exception;
}
}
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