67 lines
2.1 KiB
C#
67 lines
2.1 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading;
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using System.Threading.Tasks;
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namespace LeanCloud.Storage.Internal {
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/// <summary>
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/// Represents an event handler that calls back from the synchronization context
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/// that subscribed.
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/// <typeparam name="T">Should look like an EventArgs, but may not inherit EventArgs if T is implemented by the Windows team.</typeparam>
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/// </summary>
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public class SynchronizedEventHandler<T> {
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private LinkedList<Tuple<Delegate, TaskFactory>> delegates =
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new LinkedList<Tuple<Delegate, TaskFactory>>();
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public void Add(Delegate del) {
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lock (delegates) {
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TaskFactory factory;
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if (SynchronizationContext.Current != null) {
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factory =
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new TaskFactory(CancellationToken.None,
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TaskCreationOptions.None,
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TaskContinuationOptions.ExecuteSynchronously,
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TaskScheduler.FromCurrentSynchronizationContext());
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} else {
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factory = Task.Factory;
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}
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foreach (var d in del.GetInvocationList()) {
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delegates.AddLast(new Tuple<Delegate, TaskFactory>(d, factory));
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}
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}
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}
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public void Remove(Delegate del) {
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lock (delegates) {
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if (delegates.Count == 0) {
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return;
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}
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foreach (var d in del.GetInvocationList()) {
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var node = delegates.First;
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while (node != null) {
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if (node.Value.Item1 == d) {
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delegates.Remove(node);
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break;
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}
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node = node.Next;
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}
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}
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}
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}
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public Task Invoke(object sender, T args) {
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IEnumerable<Tuple<Delegate, TaskFactory>> toInvoke;
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var toContinue = new[] { Task.FromResult(0) };
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lock (delegates) {
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toInvoke = delegates.ToList();
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}
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var invocations = toInvoke
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.Select(p => p.Item2.ContinueWhenAll(toContinue,
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_ => p.Item1.DynamicInvoke(sender, args)))
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.ToList();
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return Task.WhenAll(invocations);
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}
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}
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}
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