43 lines
1.8 KiB
C#
43 lines
1.8 KiB
C#
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//------------------------------------------------------------------------------
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// <copyright file="PageAsyncTaskApm.cs" company="Microsoft">
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// </copyright>
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//------------------------------------------------------------------------------
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namespace System.Web.UI {
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using System;
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using System.Threading;
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using System.Threading.Tasks;
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// Represents an IPageAsyncTask that follows APM (Begin / End)
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internal sealed class PageAsyncTaskApm : IPageAsyncTask {
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private readonly BeginEventHandler _beginHandler;
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private readonly EndEventHandler _endHandler;
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private readonly object _state;
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public PageAsyncTaskApm(BeginEventHandler beginHandler, EndEventHandler endHandler, object state) {
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_beginHandler = beginHandler;
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_endHandler = endHandler;
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_state = state;
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}
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public async Task ExecuteAsync(object sender, EventArgs e, CancellationToken cancellationToken) {
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// The CancellationToken is ignored in APM since every call to Begin must be matched by
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// a call to End, otherwise memory leaks and other badness can occur.
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// The reason we don't use TaskFactory.FromAsync is that we need the end handler to execute
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// within the current synchronization context, but FromAsync doesn't make that guarantee.
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// The callback that marks the TaskCompletionSource as complete can execute synchronously or asynchronously.
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TaskCompletionSource<object> taskCompletionSource = new TaskCompletionSource<object>();
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IAsyncResult asyncResult = _beginHandler(sender, e, _ => { taskCompletionSource.SetResult(null); }, _state);
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await taskCompletionSource.Task;
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_endHandler(asyncResult);
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}
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}
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}
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