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//
// CFContentStream.cs
//
// Authors:
// Marek Safar <marek.safar@gmail.com>
//
// Copyright (C) 2013 Xamarin Inc (http://www.xamarin.com)
//
// 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.
//
using System.Threading;
using System.Threading.Tasks;
using System.IO;
using System.Net;
using System.Runtime.ExceptionServices;
#if XAMCORE_4_0
using CFNetwork;
using CoreFoundation;
#elif XAMCORE_2_0
using CoreServices;
using CoreFoundation;
#else
using MonoTouch.CoreServices;
using MonoTouch.CoreFoundation;
#endif
namespace System.Net.Http
{
class BufferData
{
public byte[] Buffer;
public int Length;
}
class CFContentStream : HttpContent
{
readonly CFHTTPStream http_stream;
BufferData data;
Mutex data_mutex;
AutoResetEvent data_event;
AutoResetEvent data_read_event;
ExceptionDispatchInfo http_exception;
// The requirements are:
// * We must read at least one byte from the stream every time
// we get a HasBytesAvailable event.
// * SerializeToStreamAsync is executed on a separate thread,
// so reads must somehow be synchronized with that thread.
//
// Current implementation:
// * We read data in ReadStreamData (on the same thread
// we got the HasBytesAvailable event, i.e. inside the
// HasBytesAvailable event handler).
// * Data is stored in a class-level buffer.
// * SerializeToStreamAsync blocks while waiting for
// data from ReadStreamData.
// * ReadStreamData will only read more data once SerializeToStreamAsync
// has consumed any existing data. This means we'll be
// blocking in the HasBytesAvailable event handler until
// any previously read data has been processed (this prevents
// any unbound memory growth).
public CFContentStream (CFHTTPStream stream)
{
this.http_stream = stream;
this.http_stream.ErrorEvent += HandleErrorEvent;
data = new BufferData () {
Buffer = new byte [4096],
};
data_event = new AutoResetEvent (false);
data_read_event = new AutoResetEvent (true);
data_mutex = new Mutex ();
}
void HandleErrorEvent (object sender, CFStream.StreamEventArgs e)
{
var gotMutex = data_mutex.WaitOne ();
if (gotMutex) {
var stream = (CFHTTPStream)sender;
if (e.EventType == CFStreamEventType.ErrorOccurred)
Volatile.Write (ref http_exception, ExceptionDispatchInfo.Capture (stream.GetError ()));
data_mutex.ReleaseMutex ();
}
}
public void ReadStreamData ()
{
data_read_event.WaitOne (); // make sure there's no pending data.
data_mutex.WaitOne ();
data.Length = (int) http_stream.Read (data.Buffer, 0, data.Buffer.Length);
data_mutex.ReleaseMutex ();
data_event.Set ();
}
public void Close ()
{
data_read_event.WaitOne (); // make sure there's no pending data
data_mutex.WaitOne ();
data = null;
this.http_stream.ErrorEvent -= HandleErrorEvent;
data_mutex.ReleaseMutex ();
data_event.Set ();
}
protected internal override async Task SerializeToStreamAsync (Stream stream, TransportContext context)
{
while (data_event.WaitOne ()) {
data_mutex.WaitOne ();
if (http_exception != null) {
http_exception.Throw ();
data_mutex.ReleaseMutex ();
break;
}
if (data == null || data.Length <= 0) {
data_mutex.ReleaseMutex ();
data_read_event.Set ();
break;
}
await stream.WriteAsync (data.Buffer, 0, data.Length).ConfigureAwait (false);
data_mutex.ReleaseMutex ();
data_read_event.Set ();
}
}
protected internal override bool TryComputeLength (out long length)
{
length = 0;
return false;
}
}
}
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