From ee8d8439ddae7c7817e0296a94c7b4e3bce123f9 Mon Sep 17 00:00:00 2001
From: Justin Kotalik <jkotalik12@gmail.com>
Date: Fri, 21 Feb 2020 16:16:44 -0800
Subject: [PATCH] Fix HttpResponseStreamWriter (#19216)

---
 .../src/HttpResponseStreamWriter.cs           | 32 ++++++++-----------
 .../test/HttpResponseStreamWriterTest.cs      |  6 ++++
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/Http/WebUtilities/src/HttpResponseStreamWriter.cs b/src/Http/WebUtilities/src/HttpResponseStreamWriter.cs
index 4f16231e14..61e42d8bc3 100644
--- a/src/Http/WebUtilities/src/HttpResponseStreamWriter.cs
+++ b/src/Http/WebUtilities/src/HttpResponseStreamWriter.cs
@@ -135,20 +135,18 @@ namespace Microsoft.AspNetCore.WebUtilities
                 throw new ObjectDisposedException(nameof(HttpResponseStreamWriter));
             }
 
-            var written = 0;
-            while (written < value.Length)
+            var remaining = value.Length;
+            while (remaining > 0)
             {
                 if (_charBufferCount == _charBufferSize)
                 {
                     FlushInternal(flushEncoder: false);
                 }
 
-                written = CopyToCharBuffer(value);
-
-                if (written < value.Length)
-                {
-                    value = value.Slice(written);
-                }
+                var written = CopyToCharBuffer(value);
+                
+                remaining -= written;
+                value = value.Slice(written);
             };
         }
 
@@ -339,20 +337,18 @@ namespace Microsoft.AspNetCore.WebUtilities
             Debug.Assert(value.Length > 0);
             Debug.Assert(_charBufferSize - _charBufferCount < value.Length);
 
-            int written = 0;
-            while (written < value.Length)
+            var remaining = value.Length;
+            while (remaining > 0)
             {
                 if (_charBufferCount == _charBufferSize)
                 {
                     await FlushInternalAsync(flushEncoder: false);
                 }
 
-                written = CopyToCharBuffer(value.Span);
-
-                if (written < value.Length)
-                {
-                    value = value.Slice(written);
-                }
+                var written = CopyToCharBuffer(value.Span);
+                
+                remaining -= written;
+                value = value.Slice(written);
             };
         }
 
@@ -389,8 +385,8 @@ namespace Microsoft.AspNetCore.WebUtilities
 
         private async Task WriteLineAsyncAwaited(ReadOnlyMemory<char> value)
         {
-            await WriteAsyncAwaited(value);
-            await WriteAsyncAwaited(NewLine);
+            await WriteAsync(value);
+            await WriteAsync(NewLine);
         }
 
         // We want to flush the stream when Flush/FlushAsync is explicitly
diff --git a/src/Http/WebUtilities/test/HttpResponseStreamWriterTest.cs b/src/Http/WebUtilities/test/HttpResponseStreamWriterTest.cs
index 61437e0bdb..aa97667360 100644
--- a/src/Http/WebUtilities/test/HttpResponseStreamWriterTest.cs
+++ b/src/Http/WebUtilities/test/HttpResponseStreamWriterTest.cs
@@ -258,6 +258,7 @@ namespace Microsoft.AspNetCore.WebUtilities
         [InlineData(1024)]
         [InlineData(1050)]
         [InlineData(2048)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1)]
         public void WriteReadOnlySpanChar_WritesToStream(int byteLength)
         {
             // Arrange
@@ -290,6 +291,7 @@ namespace Microsoft.AspNetCore.WebUtilities
         [InlineData(1050, "\r\n")]
         [InlineData(2046, "\r\n")]
         [InlineData(2048, "\r\n")]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1, "\r\n")]
         public void WriteLineReadOnlySpanChar_WritesToStream(int byteLength, string newLine)
         {
             // Arrange
@@ -360,6 +362,7 @@ namespace Microsoft.AspNetCore.WebUtilities
         [InlineData(1024)]
         [InlineData(1050)]
         [InlineData(2048)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1)]
         public async Task WriteReadOnlyMemoryAsync_WritesToStream(int byteLength)
         {
             // Arrange
@@ -412,6 +415,9 @@ namespace Microsoft.AspNetCore.WebUtilities
         [InlineData(1050, 2)]
         [InlineData(2046, 2)]
         [InlineData(2048, 2)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1, 1)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1, 2)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1, HttpResponseStreamWriter.DefaultBufferSize)]
         public async Task WriteLineReadOnlyMemoryAsync_WritesToStream(int byteLength, int newLineLength)
         {
             // Arrange