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53 lines
2.1 KiB
53 lines
2.1 KiB
#if NET20 || NET30 || NET35 || !NET_4_6 |
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using System.Diagnostics.Contracts; |
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namespace System.Threading.Tasks |
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{ |
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internal sealed class ContinuationResultTaskFromTask<TResult> : Task<TResult>, IContinuationTask |
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{ |
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private Task _antecedent; |
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public ContinuationResultTaskFromTask(Task antecedent, Delegate function, object state, TaskCreationOptions creationOptions, InternalTaskOptions internalOptions) |
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: base(function, state, InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, internalOptions, antecedent.ExecutingTaskScheduler) |
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{ |
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Contract.Requires(function is Func<Task, TResult> || function is Func<Task, object, TResult>, "Invalid delegate type in ContinuationResultTaskFromTask"); |
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_antecedent = antecedent; |
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CapturedContext = ExecutionContext.Capture(); |
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} |
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Task IContinuationTask.Antecedent |
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{ |
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get { return _antecedent; } |
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} |
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/// <summary> |
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/// Evaluates the value selector of the Task which is passed in as an object and stores the result. |
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/// </summary> |
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internal override void InnerInvoke() |
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{ |
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// Get and null out the antecedent. This is crucial to avoid a memory |
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// leak with long chains of continuations. |
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var antecedent = _antecedent; |
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Contract.Assert(antecedent != null, "No antecedent was set for the ContinuationResultTaskFromTask."); |
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_antecedent = null; |
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// Invoke the delegate |
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Contract.Assert(Action != null); |
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var func = Action as Func<Task, TResult>; |
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if (func != null) |
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{ |
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InternalResult = func(antecedent); |
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return; |
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} |
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var funcWithState = Action as Func<Task, object, TResult>; |
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if (funcWithState != null) |
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{ |
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InternalResult = funcWithState(antecedent, State); |
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return; |
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} |
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Contract.Assert(false, "Invalid Action in ContinuationResultTaskFromTask"); |
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} |
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} |
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} |
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#endif |