Avoid boxing flush ValueTask if already complete (#30)

* Avoid boxing flush ValueTask if already complete
* Bump version to 0.6.2
* Update src/RazorSlices/ValueTaskExtensions.cs

Co-authored-by: Brennan <[email protected]>

Author: DamianEdwards

src/Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 
   <PropertyGroup>
-    <VersionPrefix>0.6.1</VersionPrefix>
+    <VersionPrefix>0.6.2</VersionPrefix>
     <!-- VersionSuffix used for local builds -->
     <VersionSuffix>dev</VersionSuffix>
     <!-- VersionSuffix to be used for CI builds -->

src/RazorSlices/RazorSlice.PipeWriterExtensions.cs

@@ -37,16 +37,5 @@ public static async ValueTask RenderAsync(this RazorSlice razorSlice, Stream str
     }
 
     private static Func<CancellationToken, ValueTask> GetFlushWrapper(PipeWriter pipeWriter)
-        => ct => AsValueTask(pipeWriter.FlushAsync(ct));
-
-    private static ValueTask AsValueTask<TResult>(ValueTask<TResult> valueTask)
-    {
-        if (valueTask.IsCompletedSuccessfully)
-        {
-            var _ = valueTask.GetAwaiter().GetResult();
-            return default;
-        }
-
-        return new ValueTask(valueTask.AsTask());
-    }
+        => ct => pipeWriter.FlushAsync(ct).GetAsValueTask();
 }

src/RazorSlices/RazorSliceHttpResult.cs

@@ -53,7 +53,7 @@ Task IResult.ExecuteAsync(HttpContext httpContext)
 
         if (renderTask.HandleSynchronousCompletion())
         {
-            return httpContext.Response.BodyWriter.FlushAsync(httpContext.RequestAborted).AsTask();
+            return httpContext.Response.BodyWriter.FlushAsync(httpContext.RequestAborted).GetAsTask();
         }
 
         return AwaitRenderTaskAndFlushResponse(renderTask, httpContext.Response.BodyWriter, httpContext.RequestAborted);

src/RazorSlices/RazorSliceHttpResultOfTModel.cs

@@ -51,7 +51,7 @@ Task IResult.ExecuteAsync(HttpContext httpContext)
 
         if (renderTask.HandleSynchronousCompletion())
         {
-            return httpContext.Response.BodyWriter.FlushAsync(httpContext.RequestAborted).AsTask();
+            return httpContext.Response.BodyWriter.FlushAsync(httpContext.RequestAborted).GetAsTask();
         }
 
         return AwaitRenderTaskAndFlushResponse(renderTask, httpContext.Response.BodyWriter, httpContext.RequestAborted);

src/RazorSlices/ValueTaskExtensions.cs

@@ -0,0 +1,41 @@
+// Taken from https://github.com/dotnet/aspnetcore/blob/4eae56d8f7315cbd49fcbd760341940e3d087aa5/src/Shared/ValueTaskExtensions/ValueTaskExtensions.cs
+
+using System.IO.Pipelines;
+using System.Runtime.CompilerServices;
+
+namespace RazorSlices;
+
+internal static class ValueTaskExtensions
+{
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static Task GetAsTask(this in ValueTask<FlushResult> valueTask)
+    {
+        // Try to avoid the allocation from AsTask
+        if (valueTask.IsCompletedSuccessfully)
+        {
+            // Signal consumption to the IValueTaskSource
+            var _ = valueTask.GetAwaiter().GetResult();
+            return Task.CompletedTask;
+        }
+        else
+        {
+            return valueTask.AsTask();
+        }
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ValueTask GetAsValueTask(this in ValueTask<FlushResult> valueTask)
+    {
+        // Try to avoid the allocation from AsTask
+        if (valueTask.IsCompletedSuccessfully)
+        {
+            // Signal consumption to the IValueTaskSource
+            var _ = valueTask.GetAwaiter().GetResult();
+            return default;
+        }
+        else
+        {
+            return new ValueTask(valueTask.AsTask());
+        }
+    }
+}