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Diffstat (limited to 'src/mscorlib/shared/System/Threading/Tasks/TaskExtensions.cs')
-rw-r--r-- | src/mscorlib/shared/System/Threading/Tasks/TaskExtensions.cs | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/mscorlib/shared/System/Threading/Tasks/TaskExtensions.cs b/src/mscorlib/shared/System/Threading/Tasks/TaskExtensions.cs new file mode 100644 index 0000000000..1098299517 --- /dev/null +++ b/src/mscorlib/shared/System/Threading/Tasks/TaskExtensions.cs @@ -0,0 +1,48 @@ +// Licensed to the .NET Foundation under one or more agreements. +// The .NET Foundation licenses this file to you under the MIT license. +// See the LICENSE file in the project root for more information. + +namespace System.Threading.Tasks +{ + /// <summary>Provides a set of static methods for working with specific kinds of <see cref="Task"/> instances.</summary> + public static class TaskExtensions + { + /// <summary>Creates a proxy <see cref="Task"/> that represents the asynchronous operation of a <see cref="Task{Task}"/>.</summary> + /// <param name="task">The <see cref="Task{Task}"/> to unwrap.</param> + /// <returns>A <see cref="Task"/> that represents the asynchronous operation of the provided <see cref="Task{Task}"/>.</returns> + public static Task Unwrap(this Task<Task> task) + { + if (task == null) + { + throw new ArgumentNullException(nameof(task)); + } + + // If the task hasn't completed or was faulted/canceled, wrap it in an unwrap promise. Otherwise, + // it completed successfully. Return its inner task to avoid unnecessary wrapping, or if the inner + // task is null, return a canceled task to match the same semantics as CreateUnwrapPromise. + return + !task.IsRanToCompletion ? Task.CreateUnwrapPromise<VoidTaskResult>(task, lookForOce: false) : + task.Result ?? + Task.FromCanceled(new CancellationToken(true)); + } + + /// <summary>Creates a proxy <see cref="Task{TResult}"/> that represents the asynchronous operation of a <see cref="Task{Task{TResult}}"/>.</summary> + /// <param name="task">The <see cref="Task{Task{TResult}}"/> to unwrap.</param> + /// <returns>A <see cref="Task{TResult}"/> that represents the asynchronous operation of the provided <see cref="Task{Task{TResult}}"/>.</returns> + public static Task<TResult> Unwrap<TResult>(this Task<Task<TResult>> task) + { + if (task == null) + { + throw new ArgumentNullException(nameof(task)); + } + + // If the task hasn't completed or was faulted/canceled, wrap it in an unwrap promise. Otherwise, + // it completed successfully. Return its inner task to avoid unnecessary wrapping, or if the inner + // task is null, return a canceled task to match the same semantics as CreateUnwrapPromise. + return + !task.IsRanToCompletion ? Task.CreateUnwrapPromise<TResult>(task, lookForOce: false) : + task.Result ?? + Task.FromCanceled<TResult>(new CancellationToken(true)); + } + } +} |