Add InternalTaskExtensions with methods for returning completed tasks

Author: sharwell

src/corelib/Core/InternalTaskExtensions.cs

@@ -0,0 +1,57 @@
+namespace net.openstack.Core
+{
+    using System.Threading.Tasks;
+
+    /// <summary>
+    /// Provides extension methods to <see cref="Task"/> and <see cref="Task{TResult}"/> instances
+    /// for use within the openstack.net library.
+    /// </summary>
+    /// <threadsafety static="true" instance="false"/>
+    /// <preliminary/>
+    internal static class InternalTaskExtensions
+    {
+        /// <summary>
+        /// Gets a completed <see cref="Task"/>.
+        /// </summary>
+        /// <returns>A completed <see cref="Task"/>.</returns>
+        public static Task CompletedTask()
+        {
+            return CompletedTaskHolder.Default;
+        }
+
+        /// <summary>
+        /// Gets a completed <see cref="Task{TResult}"/> with the specified result.
+        /// </summary>
+        /// <typeparam name="TResult">The task result type.</typeparam>
+        /// <param name="result">The result of the completed task.</param>
+        /// <returns>A completed <see cref="Task{TResult}"/>, whose <see cref="Task{TResult}.Result"/> property returns the specified <paramref name="result"/>.</returns>
+        public static Task<TResult> CompletedTask<TResult>(TResult result)
+        {
+            TaskCompletionSource<TResult> completionSource = new TaskCompletionSource<TResult>();
+            completionSource.SetResult(result);
+            return completionSource.Task;
+        }
+
+        private static class CompletedTaskHolder
+        {
+            public static readonly Task Default;
+
+            static CompletedTaskHolder()
+            {
+                Default = CompletedTaskHolder<object>.Default;
+            }
+        }
+
+        private static class CompletedTaskHolder<T>
+        {
+            public static readonly Task<T> Default;
+
+            static CompletedTaskHolder()
+            {
+                TaskCompletionSource<T> completionSource = new TaskCompletionSource<T>();
+                completionSource.SetResult(default(T));
+                Default = completionSource.Task;
+            }
+        }
+    }
+}

src/corelib/corelib.v3.5.csproj

@@ -107,6 +107,7 @@
     <Compile Include="Core\Exceptions\SnapshotEnteredErrorStateException.cs" />
     <Compile Include="Core\Exceptions\VolumeEnteredErrorStateException.cs" />
     <Compile Include="Core\ExtensibleEnum`1.cs" />
+    <Compile Include="Core\InternalTaskExtensions.cs" />
     <Compile Include="Core\NamespaceDoc.cs" />
     <Compile Include="Core\ParallelExtensionsExtras\TaskCompletionSourceExtensions.cs" />
     <Compile Include="Core\ParallelExtensionsExtras\TaskExtrasExtensions.cs" />

src/corelib/corelib.v4.0.csproj

@@ -97,6 +97,7 @@
     <Compile Include="Core\Exceptions\SnapshotEnteredErrorStateException.cs" />
     <Compile Include="Core\Exceptions\VolumeEnteredErrorStateException.cs" />
     <Compile Include="Core\ExtensibleEnum`1.cs" />
+    <Compile Include="Core\InternalTaskExtensions.cs" />
     <Compile Include="Core\NamespaceDoc.cs" />
     <Compile Include="Core\ParallelExtensionsExtras\TaskCompletionSourceExtensions.cs" />
     <Compile Include="Core\ParallelExtensionsExtras\TaskExtrasExtensions.cs" />