Introducing DocumentWriter

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/DefaultDocumentWriter.cs

@@ -0,0 +1,88 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
+{
+    internal class DefaultDocumentWriter : DocumentWriter
+    {
+        private readonly CSharpRenderingContext _context;
+        private readonly RuntimeTarget _target;
+
+        private readonly PageStructureCSharpRenderer _renderer;
+
+        public DefaultDocumentWriter(RuntimeTarget target, CSharpRenderingContext context, PageStructureCSharpRenderer renderer)
+        {
+            if (target == null)
+            {
+                throw new ArgumentNullException(nameof(target));
+            }
+
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            if (renderer == null)
+            {
+                throw new ArgumentNullException(nameof(renderer));
+            }
+
+            _target = target;
+            _context = context;
+            _renderer = renderer;
+        }
+
+        public override void WriteDocument(DocumentIRNode node)
+        {
+            if (node == null)
+            {
+                throw new ArgumentNullException(nameof(node));
+            }
+
+            var visitor = new Visitor(_target, _context, _renderer);
+            _context.RenderChildren = visitor.RenderChildren;
+
+            visitor.VisitDocument(node);
+            _context.RenderChildren = null;
+        }
+
+        private class Visitor : RazorIRNodeVisitor
+        {
+            private readonly CSharpRenderingContext _context;
+            private readonly RuntimeTarget _target;
+
+            private readonly PageStructureCSharpRenderer _renderer;
+
+            public Visitor(RuntimeTarget target, CSharpRenderingContext context, PageStructureCSharpRenderer renderer)
+            {
+                _target = target;
+                _context = context;
+                _renderer = renderer;
+            }
+
+            public void RenderChildren(RazorIRNode node)
+            {
+                for (var i = 0; i < node.Children.Count; i++)
+                {
+                    var child = node.Children[i];
+                    Visit(child);
+                }
+            }
+
+            public override void VisitDocument(DocumentIRNode node)
+            {
+                RenderChildren(node);
+            }
+
+            public override void VisitDefault(RazorIRNode node)
+            {
+                // This is a temporary bridge to the renderer, which allows us to move functionality piecemeal
+                // into this class. 
+                _renderer.Visit(node);
+            }
+        }
+    }
+}

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/DefaultRuntimeTarget.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -18,16 +19,19 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 
         public IRuntimeTargetExtension[] Extensions { get; }
 
-        internal override PageStructureCSharpRenderer CreateRenderer(CSharpRenderingContext context)
+        public override DocumentWriter CreateWriter(CSharpRenderingContext context)
         {
+            PageStructureCSharpRenderer renderer;
             if (_options.DesignTimeMode)
             {
-                return new DesignTimeCSharpRenderer(this, context);
+                renderer =  new DesignTimeCSharpRenderer(this, context);
             }
             else
             {
-                return new RuntimeCSharpRenderer(this, context);
+                renderer = new RuntimeCSharpRenderer(this, context);
             }
+
+            return new DefaultDocumentWriter(this, context, renderer);
         }
 
         public override TExtension GetExtension<TExtension>()

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/DocumentWriter.cs

@@ -0,0 +1,12 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
+{
+    public abstract class DocumentWriter
+    {
+        public abstract void WriteDocument(DocumentIRNode node);
+    }
+}

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/RuntimeTarget.cs

@@ -86,7 +86,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 
         }
 
-        internal abstract PageStructureCSharpRenderer CreateRenderer(CSharpRenderingContext context);
+        public abstract DocumentWriter CreateWriter(CSharpRenderingContext context);
 
         public abstract TExtension GetExtension<TExtension>() where TExtension : class, IRuntimeTargetExtension;
 

src/Microsoft.AspNetCore.Razor.Evolution/DefaultRazorCSharpLoweringPhase.cs

@@ -56,10 +56,8 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 renderingContext.IdGenerator = () => idValue.ToString();
             }
 
-            var renderer = target.CreateRenderer(renderingContext);
-            renderingContext.RenderChildren = renderer.VisitDefault;
-
-            renderer.VisitDocument(irDocument);
+            var documentWriter = target.CreateWriter(renderingContext);
+            documentWriter.WriteDocument(irDocument);
 
             var diagnostics = new List<RazorDiagnostic>();
             diagnostics.AddRange(syntaxTree.Diagnostics);

test/Microsoft.AspNetCore.Razor.Evolution.Test/CodeGeneration/DefaultRuntimeTargetTest.cs

@@ -28,35 +28,18 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
         }
 
         [Fact]
-        public void CreateRenderer_DesignTime_CreatesDesignTimeRenderer()
+        public void CreateWriter_CreatesDefaultDocumentWriter()
         {
             // Arrange
             var options = RazorParserOptions.CreateDefaultOptions();
-            options.DesignTimeMode = true;
 
             var target = new DefaultRuntimeTarget(options, Enumerable.Empty<IRuntimeTargetExtension>());
 
             // Act
-            var renderer = target.CreateRenderer(new CSharpRenderingContext());
+            var writer = target.CreateWriter(new CSharpRenderingContext());
 
             // Assert
-            Assert.IsType<DesignTimeCSharpRenderer>(renderer);
-        }
-
-        [Fact]
-        public void CreateRenderer_Runtime_CreatesRuntimeRenderer()
-        {
-            // Arrange
-            var options = RazorParserOptions.CreateDefaultOptions();
-            options.DesignTimeMode = false;
-
-            var target = new DefaultRuntimeTarget(options, Enumerable.Empty<IRuntimeTargetExtension>());
-
-            // Act
-            var renderer = target.CreateRenderer(new CSharpRenderingContext());
-
-            // Assert
-            Assert.IsType<RuntimeCSharpRenderer>(renderer);
+            Assert.IsType<DefaultDocumentWriter>(writer);
         }
 
         [Fact]