Added internal unsafe helper to access the raw GraphQL result data. (#6937)

Author: michaelstaib

src/HotChocolate/Core/src/Execution/Internal/MiddlewareContextMarshal.cs

@@ -0,0 +1,33 @@
+using System;
+using HotChocolate.Execution.Processing;
+using HotChocolate.Resolvers;
+
+namespace HotChocolate.Execution.Internal;
+
+/// <summary>
+/// An unsafe class that provides a set of methods to access the
+/// underlying data representations of the middleware context.
+/// </summary>
+public static class MiddlewareContextMarshal
+{
+    /// <summary>
+    /// Gets access to the result data of an object in the GraphQL execution.
+    /// ResultData is pooled and writing to it can corrupt the result.
+    /// Multiple threads might be writing into the result object.
+    /// </summary>
+    /// <param name="context">
+    /// The resolver context.
+    /// </param>
+    /// <returns></returns>
+    public static ObjectResult? GetParentResultUnsafe(IResolverContext context)
+    {
+        if (context is null)
+        {
+            throw new ArgumentNullException(nameof(context));
+        }
+
+        return context is MiddlewareContext middlewareContext
+            ? middlewareContext.ParentResult
+            : null;
+    }
+}

src/HotChocolate/Core/src/Execution/Processing/MiddlewareContext.Global.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using HotChocolate.Execution.Properties;

src/HotChocolate/Core/src/Execution/Processing/PathHelper.cs

@@ -5,6 +5,8 @@ namespace HotChocolate.Execution.Processing;
 
 internal static class PathHelper
 {
+    private const int _initialPathLength = 64; 
+    
     public static Path CreatePathFromContext(ObjectResult parent)
         => CreatePath(parent);
 
@@ -18,7 +20,7 @@ public static Path CreatePathFromContext(ISelection selection, ResultData parent
 
     private static Path CreatePath(ResultData parent, object segmentValue)
     {
-        object[] segments = ArrayPool<object>.Shared.Rent(64);
+        var segments = ArrayPool<object>.Shared.Rent(_initialPathLength);
         segments[0] = segmentValue;
         var length = Build(segments, parent);
         var path = CreatePath(parent.PatchPath, segments, length);
@@ -28,7 +30,7 @@ private static Path CreatePath(ResultData parent, object segmentValue)
 
     private static Path CreatePath(ResultData parent)
     {
-        var segments = ArrayPool<object>.Shared.Rent(64);
+        var segments = ArrayPool<object>.Shared.Rent(_initialPathLength);
         var length = Build(segments, parent, 0);
         var path = CreatePath(parent.PatchPath, segments, length);
         ArrayPool<object>.Shared.Return(segments);