src/csharp/Grpc.Core/Utils/RecordingObserver.cs

#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,
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#endregion

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace Grpc.Core.Utils
{
    public class RecordingObserver<T> : IObserver<T>
    {
        TaskCompletionSource<List<T>> tcs = new TaskCompletionSource<List<T>>();
        List<T> data = new List<T>();

        public void OnCompleted()
        {
            tcs.SetResult(data);
        }

        public void OnError(Exception error)
        {
            tcs.SetException(error);
        }

        public void OnNext(T value)
        {
            data.Add(value);
        }

        public Task<List<T>> ToList() {
            return tcs.Task;
        }
    }
}