102 lines
2.1 KiB
C#
102 lines
2.1 KiB
C#
// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
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using System;
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using System.Collections.Generic;
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using System.Runtime.CompilerServices;
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using System.Security;
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#if HAS_AWAIT
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namespace System.Linq
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{
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public interface IYielder<in T>
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{
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IAwaitable Return(T value);
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IAwaitable Break();
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}
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class Yielder<T> : IYielder<T>, IAwaitable, IAwaiter
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{
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private readonly Action<Yielder<T>> _create;
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private bool _running;
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private bool _hasValue;
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private T _value;
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private bool _stopped;
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private Action _continuation;
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public Yielder(Action<Yielder<T>> create)
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{
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_create = create;
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}
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public IAwaitable Return(T value)
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{
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_hasValue = true;
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_value = value;
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return this;
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}
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public IAwaitable Break()
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{
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_stopped = true;
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return this;
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}
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public Yielder<T> GetEnumerator()
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{
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return this;
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}
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public bool MoveNext()
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{
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if (!_running)
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{
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_running = true;
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_create(this);
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}
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else
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{
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_hasValue = false;
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_continuation();
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}
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return !_stopped && _hasValue;
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}
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public T Current
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{
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get
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{
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return _value;
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}
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}
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public void Reset()
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{
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throw new NotSupportedException();
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}
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public IAwaiter GetAwaiter()
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{
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return this;
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}
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public bool IsCompleted
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{
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get { return false; }
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}
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public void GetResult() { }
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[SecurityCritical]
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public void UnsafeOnCompleted(Action continuation)
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{
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_continuation = continuation;
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}
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public void OnCompleted(Action continuation)
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{
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_continuation = continuation;
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}
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}
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}
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#endif
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