96 lines
2.8 KiB
C#
96 lines
2.8 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.Collections.Generic;
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namespace System.Reactive
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{
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class EventSource<T> : IEventSource<T>
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{
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private readonly IObservable<T> _source;
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private readonly Dictionary<Delegate, Stack<IDisposable>> _subscriptions;
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private readonly Action<Action<T>, /*object,*/ T> _invokeHandler;
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public EventSource(IObservable<T> source, Action<Action<T>, /*object,*/ T> invokeHandler)
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{
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_source = source;
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_invokeHandler = invokeHandler;
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_subscriptions = new Dictionary<Delegate, Stack<IDisposable>>();
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}
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public event Action<T> OnNext
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{
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add
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{
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var gate = new object();
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var isAdded = false;
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var isDone = false;
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var remove = new Action(() =>
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{
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lock (gate)
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{
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if (isAdded)
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Remove(value);
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else
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isDone = true;
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}
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});
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//
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// [OK] Use of unsafe Subscribe: non-pretentious wrapper of an observable in an event; exceptions can occur during +=.
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//
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var d = _source.Subscribe/*Unsafe*/(
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x => _invokeHandler(value, /*this,*/ x),
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ex => { remove(); ex.Throw(); },
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() => remove()
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);
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lock (gate)
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{
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if (!isDone)
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{
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Add(value, d);
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isAdded = true;
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}
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}
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}
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remove
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{
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Remove(value);
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}
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}
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private void Add(Delegate handler, IDisposable disposable)
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{
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lock (_subscriptions)
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{
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var l = new Stack<IDisposable>();
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if (!_subscriptions.TryGetValue(handler, out l))
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_subscriptions[handler] = l = new Stack<IDisposable>();
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l.Push(disposable);
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}
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}
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private void Remove(Delegate handler)
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{
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var d = default(IDisposable);
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lock (_subscriptions)
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{
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var l = new Stack<IDisposable>();
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if (_subscriptions.TryGetValue(handler, out l))
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{
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d = l.Pop();
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if (l.Count == 0)
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_subscriptions.Remove(handler);
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}
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}
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if (d != null)
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d.Dispose();
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}
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}
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}
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