Remove TextWriter.ToString from RazorPage

Fixes #3668

src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs

@@ -30,7 +30,7 @@ namespace Microsoft.AspNet.Mvc.Razor
     public abstract class RazorPage : IRazorPage
     {
         private readonly HashSet<string> _renderedSections = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
-        private readonly Stack<TextWriter> _writerScopes;
+        private readonly Stack<HtmlContentWrapperTextWriter> _writerScopes;
         private TextWriter _originalWriter;
         private IUrlHelper _urlHelper;
         private ITagHelperActivator _tagHelperActivator;
@@ -44,7 +44,7 @@ namespace Microsoft.AspNet.Mvc.Razor
         public RazorPage()
         {
             SectionWriters = new Dictionary<string, RenderAsyncDelegate>(StringComparer.OrdinalIgnoreCase);
-            _writerScopes = new Stack<TextWriter>();
+            _writerScopes = new Stack<HtmlContentWrapperTextWriter>();
         }
 
         /// <summary>
@@ -209,30 +209,15 @@ namespace Microsoft.AspNet.Mvc.Razor
         /// </remarks>
         public void StartTagHelperWritingScope()
         {
-            var buffer = new ViewBuffer(BufferScope, Path);
-            StartTagHelperWritingScope(new HtmlContentWrapperTextWriter(buffer, Output.Encoding));
-        }
-
-        /// <summary>
-        /// Starts a new writing scope with the given <paramref name="writer"/>.
-        /// </summary>
-        /// <remarks>
-        /// All writes to the <see cref="Output"/> or <see cref="ViewContext.Writer"/> after calling this method will
-        /// be buffered until <see cref="EndTagHelperWritingScope"/> is called.
-        /// </remarks>
-        public void StartTagHelperWritingScope(TextWriter writer)
-        {
-            if (writer == null)
-            {
-                throw new ArgumentNullException(nameof(writer));
-            }
-
             // If there isn't a base writer take the ViewContext.Writer
             if (_originalWriter == null)
             {
                 _originalWriter = ViewContext.Writer;
             }
 
+            var buffer = new ViewBuffer(BufferScope, Path);
+            var writer = new HtmlContentWrapperTextWriter(buffer, _originalWriter.Encoding);
+
             // We need to replace the ViewContext's Writer to ensure that all content (including content written
             // from HTML helpers) is redirected.
             ViewContext.Writer = writer;
@@ -243,8 +228,7 @@ namespace Microsoft.AspNet.Mvc.Razor
         /// <summary>
         /// Ends the current writing scope that was started by calling <see cref="StartTagHelperWritingScope"/>.
         /// </summary>
-        /// <returns>The <see cref="TextWriter"/> that contains the content written to the <see cref="Output"/> or
+        /// <returns>The buffered <see cref="TagHelperContent"/>.</returns>
-        /// <see cref="ViewContext.Writer"/> during the writing scope.</returns>
         public TagHelperContent EndTagHelperWritingScope()
         {
             if (_writerScopes.Count == 0)
@@ -253,6 +237,7 @@ namespace Microsoft.AspNet.Mvc.Razor
             }
 
             var writer = _writerScopes.Pop();
+            Debug.Assert(writer == ViewContext.Writer);
 
             if (_writerScopes.Count > 0)
             {
@@ -267,24 +252,7 @@ namespace Microsoft.AspNet.Mvc.Razor
             }
 
             var tagHelperContent = new DefaultTagHelperContent();
-            var razorWriter = writer as RazorTextWriter;
+            tagHelperContent.Append(writer.ContentBuilder);
-            if (razorWriter != null)
-            {
-                tagHelperContent.Append(razorWriter.Buffer);
-            }
-            else
-            {
-                var htmlContentTextWriter = writer as HtmlContentWrapperTextWriter;
-                if (htmlContentTextWriter != null)
-                {
-                    tagHelperContent.Append(htmlContentTextWriter.ContentBuilder);
-                }
-                else
-                {
-                    tagHelperContent.AppendHtml(writer.ToString());
-                }
-            }
-
             return tagHelperContent;
         }
 

src/Microsoft.AspNet.Mvc.Razor/TagHelperContentWrapperTextWriter.cs

@@ -1,78 +0,0 @@
-// 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.Text;
-using Microsoft.AspNet.Html;
-using Microsoft.AspNet.Razor.TagHelpers;
-
-namespace Microsoft.AspNet.Mvc.Razor
-{
-    /// <summary>
-    /// <see cref="HtmlTextWriter"/> implementation which writes to a <see cref="TagHelperContent"/> instance.
-    /// </summary>
-    public class TagHelperContentWrapperTextWriter : HtmlTextWriter
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="TagHelperContentWrapperTextWriter"/> class.
-        /// </summary>
-        /// <param name="encoding">The <see cref="Encoding"/> in which output is written.</param>
-        public TagHelperContentWrapperTextWriter(Encoding encoding)
-            : this(encoding, new DefaultTagHelperContent())
-        {
-        }
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="TagHelperContentWrapperTextWriter"/> class.
-        /// </summary>
-        /// <param name="encoding">The <see cref="Encoding"/> in which output is written.</param>
-        /// <param name="content">The <see cref="TagHelperContent"/> to write to.</param>
-        public TagHelperContentWrapperTextWriter(Encoding encoding, TagHelperContent content)
-        {
-            if (encoding == null)
-            {
-                throw new ArgumentNullException(nameof(encoding));
-            }
-
-            if (content == null)
-            {
-                throw new ArgumentNullException(nameof(content));
-            }
-
-            Content = content;
-            Encoding = encoding;
-        }
-
-        /// <summary>
-        /// The <see cref="TagHelperContent"/> this <see cref="TagHelperContentWrapperTextWriter"/> writes to.
-        /// </summary>
-        public TagHelperContent Content { get; }
-
-        /// <inheritdoc />
-        public override Encoding Encoding { get; }
-
-        /// <inheritdoc />
-        public override void Write(string value)
-        {
-            Content.AppendHtml(value);
-        }
-
-        /// <inheritdoc />
-        public override void Write(char value)
-        {
-            Content.AppendHtml(value.ToString());
-        }
-
-        /// <inheritdoc />
-        public override void Write(IHtmlContent value)
-        {
-            Content.Append(value);
-        }
-
-        /// <inheritdoc />
-        public override string ToString()
-        {
-            return Content.ToString();
-        }
-    }
-}

test/Microsoft.AspNet.Mvc.Razor.Test/RazorPageTest.cs

@@ -175,32 +175,6 @@ namespace Microsoft.AspNet.Mvc.Razor
             await page.ExecuteAsync();
         }
 
-        [Fact]
-        public async Task EndTagHelperWritingScope_CopiesContent_IfRazorTextWriter()
-        {
-            // Arrange
-            var viewContext = CreateViewContext();
-
-            // Act
-            var page = CreatePage(v =>
-            {
-                v.HtmlEncoder = new HtmlTestEncoder();
-                var buffer = new ViewBuffer(new TestViewBufferScope(), v.Path);
-                v.StartTagHelperWritingScope(new RazorTextWriter(TextWriter.Null, buffer, v.HtmlEncoder));
-                v.Write("Hello ");
-                v.Write("World!");
-                var returnValue = v.EndTagHelperWritingScope();
-
-                // Assert
-                var content = Assert.IsType<DefaultTagHelperContent>(returnValue);
-                Assert.Equal("HtmlEncode[[Hello ]]HtmlEncode[[World!]]", content.GetContent());
-                Assert.Equal(
-                    "HtmlEncode[[Hello ]]HtmlEncode[[World!]]",
-                    HtmlContentUtilities.HtmlContentToString(content));
-            }, viewContext);
-            await page.ExecuteAsync();
-        }
-
         [Fact]
         public async Task DefineSection_ThrowsIfSectionIsAlreadyDefined()
         {