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#region Copyright notice and license
// Copyright 2015, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion
using System;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using Grpc.Core.Internal;
using Grpc.Core.Utils;
namespace Grpc.Core.Internal
{
/// <summary>
/// Manages server side native call lifecycle.
/// </summary>
internal class AsyncCallServer<TRequest, TResponse> : AsyncCallBase<TResponse, TRequest>
{
readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
readonly Server server;
public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment, Server server) : base(serializer, deserializer, environment)
{
this.server = Preconditions.CheckNotNull(server);
}
public void Initialize(CallSafeHandle call)
{
call.Initialize(environment.CompletionRegistry, environment.CompletionQueue);
server.AddCallReference(this);
InitializeInternal(call);
}
/// <summary>
/// Starts a server side call.
/// </summary>
public Task ServerSideCallAsync()
{
lock (myLock)
{
Preconditions.CheckNotNull(call);
started = true;
call.StartServerSide(HandleFinishedServerside);
return finishedServersideTcs.Task;
}
}
/// <summary>
/// Sends a streaming response. Only one pending send action is allowed at any given time.
/// completionDelegate is called when the operation finishes.
/// </summary>
public void StartSendMessage(TResponse msg, WriteFlags writeFlags, AsyncCompletionDelegate<object> completionDelegate)
{
StartSendMessageInternal(msg, writeFlags, completionDelegate);
}
/// <summary>
/// Receives a streaming request. Only one pending read action is allowed at any given time.
/// completionDelegate is called when the operation finishes.
/// </summary>
public void StartReadMessage(AsyncCompletionDelegate<TRequest> completionDelegate)
{
StartReadMessageInternal(completionDelegate);
}
/// <summary>
/// Initiates sending a initial metadata.
/// Even though C-core allows sending metadata in parallel to sending messages, we will treat sending metadata as a send message operation
/// to make things simpler.
/// completionDelegate is invoked upon completion.
/// </summary>
public void StartSendInitialMetadata(Metadata headers, AsyncCompletionDelegate<object> completionDelegate)
{
lock (myLock)
{
Preconditions.CheckNotNull(headers, "metadata");
Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
Preconditions.CheckState(!initialMetadataSent, "Response headers can only be sent once per call.");
Preconditions.CheckState(streamingWritesCounter == 0, "Response headers can only be sent before the first write starts.");
CheckSendingAllowed();
Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
using (var metadataArray = MetadataArraySafeHandle.Create(headers))
{
call.StartSendInitialMetadata(HandleSendFinished, metadataArray);
}
this.initialMetadataSent = true;
sendCompletionDelegate = completionDelegate;
}
}
/// <summary>
/// Sends call result status, also indicating server is done with streaming responses.
/// Only one pending send action is allowed at any given time.
/// completionDelegate is called when the operation finishes.
/// </summary>
public void StartSendStatusFromServer(Status status, Metadata trailers, AsyncCompletionDelegate<object> completionDelegate)
{
lock (myLock)
{
Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
CheckSendingAllowed();
using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
{
call.StartSendStatusFromServer(HandleHalfclosed, status, metadataArray, !initialMetadataSent);
}
halfcloseRequested = true;
readingDone = true;
sendCompletionDelegate = completionDelegate;
}
}
/// <summary>
/// Gets cancellation token that gets cancelled once close completion
/// is received and the cancelled flag is set.
/// </summary>
public CancellationToken CancellationToken
{
get
{
return cancellationTokenSource.Token;
}
}
public string Peer
{
get
{
return call.GetPeer();
}
}
protected override bool IsClient
{
get { return false; }
}
protected override void CheckReadingAllowed()
{
base.CheckReadingAllowed();
Preconditions.CheckArgument(!cancelRequested);
}
protected override void OnAfterReleaseResources()
{
server.RemoveCallReference(this);
}
/// <summary>
/// Handles the server side close completion.
/// </summary>
private void HandleFinishedServerside(bool success, bool cancelled)
{
lock (myLock)
{
finished = true;
if (cancelled)
{
// Once we cancel, we don't have to care that much
// about reads and writes.
// TODO(jtattermusch): is this still necessary?
Cancel();
}
ReleaseResourcesIfPossible();
}
// TODO(jtattermusch): handle error
if (cancelled)
{
cancellationTokenSource.Cancel();
}
finishedServersideTcs.SetResult(null);
}
}
}
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