grpc/src/csharp/Grpc.Core/Calls.cs

#region Copyright notice and license

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// 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.
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
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#endregion

using System;
using System.Threading;
using System.Threading.Tasks;
using Grpc.Core.Internal;

namespace Grpc.Core
{
    /// <summary>
    /// Helper methods for generated clients to make RPC calls.
    /// </summary>
    public static class Calls
    {
        public static TResponse BlockingUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req)
            where TRequest : class
            where TResponse : class
        {
            var asyncCall = new AsyncCall<TRequest, TResponse>(call.Channel, call.Method.FullName, call.Host, call.Context,
                call.Method.RequestMarshaller.Serializer, call.Method.ResponseMarshaller.Deserializer);
            // TODO(jtattermusch): this gives a race that cancellation can be requested before the call even starts.
            RegisterCancellationCallback(asyncCall, call.Context.CancellationToken);
            return asyncCall.UnaryCall(req);
        }

        public static AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req)
            where TRequest : class
            where TResponse : class
        {
            var asyncCall = new AsyncCall<TRequest, TResponse>(call.Channel, call.Method.FullName, call.Host, call.Context,
                call.Method.RequestMarshaller.Serializer, call.Method.ResponseMarshaller.Deserializer);
            var asyncResult = asyncCall.UnaryCallAsync(req);
            RegisterCancellationCallback(asyncCall, call.Context.CancellationToken);
            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
        }

        public static AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req)
            where TRequest : class
            where TResponse : class
        {
            var asyncCall = new AsyncCall<TRequest, TResponse>(call.Channel, call.Method.FullName, call.Host, call.Context,
                call.Method.RequestMarshaller.Serializer, call.Method.ResponseMarshaller.Deserializer);
            asyncCall.StartServerStreamingCall(req);
            RegisterCancellationCallback(asyncCall, call.Context.CancellationToken);
            var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
        }

        public static AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call)
            where TRequest : class
            where TResponse : class
        {
            var asyncCall = new AsyncCall<TRequest, TResponse>(call.Channel, call.Method.FullName, call.Host, call.Context,
                call.Method.RequestMarshaller.Serializer, call.Method.ResponseMarshaller.Deserializer);
            var resultTask = asyncCall.ClientStreamingCallAsync();
            RegisterCancellationCallback(asyncCall, call.Context.CancellationToken);
            var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
        }

        public static AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call)
            where TRequest : class
            where TResponse : class
        {
            var asyncCall = new AsyncCall<TRequest, TResponse>(call.Channel, call.Method.FullName, call.Host, call.Context,
                call.Method.RequestMarshaller.Serializer, call.Method.ResponseMarshaller.Deserializer);
            asyncCall.StartDuplexStreamingCall();
            RegisterCancellationCallback(asyncCall, call.Context.CancellationToken);
            var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
            var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
        }

        private static void RegisterCancellationCallback<TRequest, TResponse>(AsyncCall<TRequest, TResponse> asyncCall, CancellationToken token)
        {
            if (token.CanBeCanceled)
            {
                token.Register(() => asyncCall.Cancel());
            }
        }
    }
}