Prevent newlines from being encoded in the output (dotnet/aspnetcore-tooling#374)

* Prevent newlines from being encoded in the output
\n\nCommit migrated from 5f74fae0d2

src/Razor/Microsoft.AspNetCore.Mvc.Razor.Extensions/test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent_Runtime.codegen.cs

@@ -16,9 +16,9 @@ namespace __GeneratedComponent
         {
             builder.OpenElement(0, "div");
             builder.AddAttribute(1, "class", this.ToString());
-            builder.AddContent(2, "\r\n    Hello world\r\n    ");
+            builder.AddMarkupContent(2, "\r\n    Hello world\r\n    ");
             builder.AddContent(3, string.Format("{0}", "Hello"));
-            builder.AddContent(4, "\r\n");
+            builder.AddMarkupContent(4, "\r\n");
             builder.CloseElement();
         }
         #pragma warning restore 1998

src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentMarkupEncodingPass.cs

@@ -0,0 +1,71 @@
+// 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.Linq;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Language.Components
+{
+    internal class ComponentMarkupEncodingPass : ComponentIntermediateNodePassBase, IRazorOptimizationPass
+    {
+        // Runs after ComponentMarkupBlockPass
+        public override int Order => 10010;
+
+        protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+        {
+            if (!IsComponentDocument(documentNode))
+            {
+                return;
+            }
+
+            if (documentNode.Options.DesignTime)
+            {
+                // Nothing to do during design time.
+                return;
+            }
+
+            var rewriter = new Rewriter();
+            rewriter.Visit(documentNode);
+        }
+
+        private class Rewriter : IntermediateNodeWalker
+        {
+            // Markup content in components are rendered in one of the following two ways,
+            // AddContent - we encode it when used with prerendering and inserted into the DOM in a safe way (low perf impact)
+            // AddMarkupContent - renders the content directly as markup (high perf impact)
+            // Because of this, we want to use AddContent as much as possible.
+            //
+            // We want to use AddMarkupContent to avoid aggresive encoding during prerendering.
+            // Specifically, when one of the following characters are in the content,
+            // 1. New lines (\r, \n), tabs(\t) - so they get rendered as actual new lines, tabs instead of 

+            // 2. Ampersands (&) - so that HTML entities are rendered correctly without getting encoded
+            // 3. Any character outside the ASCII range
+
+            private static readonly char[] EncodedCharacters = new[] { '\r', '\n', '\t', '&' };
+
+            public override void VisitHtml(HtmlContentIntermediateNode node)
+            {
+                for (var i = 0; i < node.Children.Count; i++)
+                {
+                    var child = node.Children[i];
+                    if (!(child is IntermediateToken token) || !token.IsHtml)
+                    {
+                        // We only care about Html tokens.
+                        continue;
+                    }
+
+                    for (var j = 0; j < token.Content.Length; j++)
+                    {
+                        var ch = token.Content[j];
+                        // ASCII range is 0 - 127
+                        if (ch > 127 || EncodedCharacters.Contains(ch))
+                        {
+                            node.SetEncoded();
+                            return;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs

@@ -98,7 +98,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             // Since we're not in the middle of writing an element, this must evaluate as some
             // text to display
             context.CodeWriter
-                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{nameof(ComponentsApi.RenderTreeBuilder.AddContent)}")
+                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{ComponentsApi.RenderTreeBuilder.AddContent}")
                 .Write((_sourceSequence++).ToString())
                 .WriteParameterSeparator();
 
@@ -158,7 +158,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             }
 
             context.CodeWriter
-                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{nameof(ComponentsApi.RenderTreeBuilder.AddMarkupContent)}")
+                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{ComponentsApi.RenderTreeBuilder.AddMarkupContent}")
                 .Write((_sourceSequence++).ToString())
                 .WriteParameterSeparator()
                 .WriteStringLiteral(node.Content)
@@ -178,7 +178,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             }
 
             context.CodeWriter
-                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{nameof(ComponentsApi.RenderTreeBuilder.OpenElement)}")
+                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{ComponentsApi.RenderTreeBuilder.OpenElement}")
                 .Write((_sourceSequence++).ToString())
                 .WriteParameterSeparator()
                 .WriteStringLiteral(node.TagName)
@@ -255,8 +255,15 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
 
             // Text node
             var content = GetHtmlContent(node);
+            var renderApi = ComponentsApi.RenderTreeBuilder.AddContent;
+            if (node.IsEncoded())
+            {
+                // This content is already encoded.
+                renderApi = ComponentsApi.RenderTreeBuilder.AddMarkupContent;
+            }
+
             context.CodeWriter
-                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{nameof(ComponentsApi.RenderTreeBuilder.AddContent)}")
+                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{renderApi}")
                 .Write((_sourceSequence++).ToString())
                 .WriteParameterSeparator()
                 .WriteStringLiteral(content)
@@ -644,8 +651,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             var codeWriter = context.CodeWriter;
 
             var methodName = node.IsComponentCapture
-                ? nameof(ComponentsApi.RenderTreeBuilder.AddComponentReferenceCapture)
+                ? ComponentsApi.RenderTreeBuilder.AddComponentReferenceCapture
-                : nameof(ComponentsApi.RenderTreeBuilder.AddElementReferenceCapture);
+                : ComponentsApi.RenderTreeBuilder.AddElementReferenceCapture;
             codeWriter
                 .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{methodName}")
                 .Write((_sourceSequence++).ToString())
@@ -693,7 +700,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
         protected override void BeginWriteAttribute(CodeWriter codeWriter, string key)
         {
             codeWriter
-                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{nameof(ComponentsApi.RenderTreeBuilder.AddAttribute)}")
+                .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{ComponentsApi.RenderTreeBuilder.AddAttribute}")
                 .Write((_sourceSequence++).ToString())
                 .WriteParameterSeparator()
                 .WriteStringLiteral(key)

src/Razor/Microsoft.AspNetCore.Razor.Language/src/Intermediate/HtmlContentIntermediateNodeExtensions.cs

@@ -0,0 +1,27 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Razor.Language.Intermediate
+{
+    internal static class HtmlContentIntermediateNodeExtensions
+    {
+        private static readonly string HasEncodedContent = "HasEncodedContent";
+
+        public static bool IsEncoded(this HtmlContentIntermediateNode node)
+        {
+            return ReferenceEquals(node.Annotations[HasEncodedContent], HasEncodedContent);
+        }
+
+        public static void SetEncoded(this HtmlContentIntermediateNode node)
+        {
+            if (node == null)
+            {
+                throw new ArgumentNullException(nameof(node));
+            }
+
+            node.Annotations[HasEncodedContent] = HasEncodedContent;
+        }
+    }
+}

src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectEngine.cs

@@ -232,6 +232,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             builder.Features.Add(new ComponentGenericTypePass());
             builder.Features.Add(new ComponentChildContentDiagnosticPass());
             builder.Features.Add(new ComponentMarkupBlockPass());
+            builder.Features.Add(new ComponentMarkupEncodingPass());
         }
 
         private static void LoadExtensions(RazorProjectEngineBuilder builder, IReadOnlyList<RazorExtension> extensions)