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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 = GrpcPreconditions.CheckNotNull(server);
}
public void Initialize(CallSafeHandle call)
{
call.Initialize(environment.CompletionRegistry, environment.CompletionQueue);
server.AddCallReference(this);
InitializeInternal(call);
}
/// <summary>
/// Only for testing purposes.
/// </summary>
public void InitializeForTesting(INativeCall call)
{
server.AddCallReference(this);
InitializeInternal(call);
}
/// <summary>
/// Starts a server side call.
/// </summary>
public Task ServerSideCallAsync()
{
lock (myLock)
{
GrpcPreconditions.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.
/// </summary>
public Task<TRequest> ReadMessageAsync()
{
return ReadMessageInternalAsync();
}
/// <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)
{
GrpcPreconditions.CheckNotNull(headers, "metadata");
GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
GrpcPreconditions.CheckState(!initialMetadataSent, "Response headers can only be sent once per call.");
GrpcPreconditions.CheckState(streamingWritesCounter == 0, "Response headers can only be sent before the first write starts.");
CheckSendingAllowed(allowFinished: false);
GrpcPreconditions.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, indicating we are done with writes.
/// Sending a status different from StatusCode.OK will also implicitly cancel the call.
/// </summary>
public Task SendStatusFromServerAsync(Status status, Metadata trailers, Tuple<TResponse, WriteFlags> optionalWrite)
{
byte[] payload = optionalWrite != null ? UnsafeSerialize(optionalWrite.Item1) : null;
var writeFlags = optionalWrite != null ? optionalWrite.Item2 : default(WriteFlags);
lock (myLock)
{
GrpcPreconditions.CheckState(started);
GrpcPreconditions.CheckState(!disposed);
GrpcPreconditions.CheckState(!halfcloseRequested, "Can only send status from server once.");
using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
{
call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent,
payload, writeFlags);
}
halfcloseRequested = true;
initialMetadataSent = true;
sendStatusFromServerTcs = new TaskCompletionSource<object>();
if (optionalWrite != null)
{
streamingWritesCounter++;
}
return sendStatusFromServerTcs.Task;
}
}
/// <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 OnAfterReleaseResources()
{
server.RemoveCallReference(this);
}
/// <summary>
/// Handles the server side close completion.
/// </summary>
private void HandleFinishedServerside(bool success, bool cancelled)
{
// NOTE: because this event is a result of batch containing GRPC_OP_RECV_CLOSE_ON_SERVER,
// success will be always set to true.
lock (myLock)
{
finished = true;
if (streamingReadTcs == null)
{
// if there's no pending read, readingDone=true will dispose now.
// if there is a pending read, we will dispose once that read finishes.
readingDone = true;
streamingReadTcs = new TaskCompletionSource<TRequest>();
streamingReadTcs.SetResult(default(TRequest));
}
ReleaseResourcesIfPossible();
}
if (cancelled)
{
cancellationTokenSource.Cancel();
}
finishedServersideTcs.SetResult(null);
}
}
}
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