Consistently use CharArrayPool in JsonWriter to cut cost of initializ…

…ing char arrays

src/Microsoft.OData.Core/Json/JsonWriter.cs

@@ -215,7 +215,7 @@ public void WriteName(string name)
 
             currentScope.ObjectCount++;
 
-            JsonValueUtils.WriteEscapedJsonString(this.writer, name, this.stringEscapeOption, this.wrappedBuffer);
+            JsonValueUtils.WriteEscapedJsonString(this.writer, name, this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool);
             this.writer.Write(JsonConstants.NameValueSeparator);
         }
 
@@ -280,7 +280,7 @@ public void WriteValue(long value)
             if (isIeee754Compatible)
             {
                 JsonValueUtils.WriteValue(this.writer, value.ToString(CultureInfo.InvariantCulture),
-                    this.stringEscapeOption, this.wrappedBuffer);
+                    this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool);
             }
             else
             {
@@ -320,7 +320,7 @@ public void WriteValue(decimal value)
             if (isIeee754Compatible)
             {
                 JsonValueUtils.WriteValue(this.writer, value.ToString(CultureInfo.InvariantCulture),
-                    this.stringEscapeOption, this.wrappedBuffer);
+                    this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool);
             }
             else
             {
@@ -395,7 +395,7 @@ public void WriteValue(sbyte value)
         public void WriteValue(string value)
         {
             this.WriteValueSeparator();
-            JsonValueUtils.WriteValue(this.writer, value, this.stringEscapeOption, this.wrappedBuffer);
+            JsonValueUtils.WriteValue(this.writer, value, this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool);
         }
 
         /// <summary>

src/Microsoft.OData.Core/Json/JsonWriterAsync.cs

@@ -100,7 +100,7 @@ public async Task WriteNameAsync(string name)
 
             currentScope.ObjectCount++;
 
-            await this.writer.WriteEscapedJsonStringAsync(name, this.stringEscapeOption, this.wrappedBuffer)
+            await this.writer.WriteEscapedJsonStringAsync(name, this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool)
                 .ConfigureAwait(false);
             await this.writer.WriteAsync(JsonConstants.NameValueSeparator).ConfigureAwait(false);
         }
@@ -148,7 +148,7 @@ public async Task WriteValueAsync(long value)
             if (isIeee754Compatible)
             {
                 await this.writer.WriteValueAsync(value.ToString(CultureInfo.InvariantCulture),
-                    this.stringEscapeOption, this.wrappedBuffer).ConfigureAwait(false);
+                    this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool).ConfigureAwait(false);
             }
             else
             {
@@ -179,7 +179,7 @@ public async Task WriteValueAsync(decimal value)
             if (isIeee754Compatible)
             {
                 await this.writer.WriteValueAsync(value.ToString(CultureInfo.InvariantCulture),
-                    this.stringEscapeOption, this.wrappedBuffer).ConfigureAwait(false);
+                    this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool).ConfigureAwait(false);
             }
             else
             {
@@ -234,15 +234,15 @@ public async Task WriteValueAsync(sbyte value)
         public async Task WriteValueAsync(string value)
         {
             await this.WriteValueSeparatorAsync().ConfigureAwait(false);
-            await this.writer.WriteValueAsync(value, this.stringEscapeOption, this.wrappedBuffer)
+            await this.writer.WriteValueAsync(value, this.stringEscapeOption, this.wrappedBuffer, this.ArrayPool)
                 .ConfigureAwait(false);
         }
 
         /// <inheritdoc/>
         public async Task WriteValueAsync(byte[] value)
         {
             await this.WriteValueSeparatorAsync().ConfigureAwait(false);
-            await this.writer.WriteValueAsync(value, this.wrappedBuffer, ArrayPool).ConfigureAwait(false);
+            await this.writer.WriteValueAsync(value, this.wrappedBuffer, this.ArrayPool).ConfigureAwait(false);
         }
 
         /// <inheritdoc/>
@@ -270,7 +270,7 @@ public async Task<Stream> StartStreamValueScopeAsync()
             // ODL supports net45 and netstandard1.1 (in addition to .netstandard2.0)
             // This makes it complicated to implement IAsyncDisposable in ODataBinaryStreamWriter
             // TODO: Can the returned stream be safely used asynchronously?
-            this.binaryValueStream = new ODataBinaryStreamWriter(writer, this.wrappedBuffer, ArrayPool);
+            this.binaryValueStream = new ODataBinaryStreamWriter(writer, this.wrappedBuffer, this.ArrayPool);
             return this.binaryValueStream;
         }
 

test/FunctionalTests/Microsoft.OData.Core.Tests/Json/JsonWriterAsyncTests.cs

@@ -5,13 +5,13 @@
 //---------------------------------------------------------------------
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
-using Microsoft.OData.Json;
+using System.Threading.Tasks;
 using Microsoft.OData.Edm;
+using Microsoft.OData.Json;
 using Xunit;
-using System.Threading.Tasks;
-using System.Collections.Generic;
 
 namespace Microsoft.OData.Tests.Json
 {
@@ -359,5 +359,35 @@ private async Task VerifyWriterPrimitiveValueWithIeee754CompatibleAsync<T>(T par
         }
 
         #endregion
+
+        [Fact]
+        public Task WriteNameAsyncUsesProvidedCharArrayPool()
+        {
+            // Note: CharArrayPool is used if string has special chars
+            // This test is mostly theoretical since special characters are not allowed in names
+            return SetupJsonWriterRunTestAndVerifyRentAsync(
+                (jsonWriter) => jsonWriter.WriteNameAsync("foo\tbar"));
+        }
+
+        [Fact]
+        public Task WriteStringValueUsesProvidedCharArrayPool()
+        {
+            return SetupJsonWriterRunTestAndVerifyRentAsync(
+                (jsonWriter) => jsonWriter.WriteValueAsync("foo\tbar"));
+        }
+
+        private async Task SetupJsonWriterRunTestAndVerifyRentAsync(Func<JsonWriter, Task> func)
+        {
+            var jsonWriter = new JsonWriter(new StringWriter(builder), isIeee754Compatible: true);
+            bool rentVerified = false;
+
+            Action<int> rentVerifier = (minSize) => { rentVerified = true; };
+            jsonWriter.ArrayPool = new MockCharArrayPool { RentVerifier = rentVerifier };
+
+            await jsonWriter.StartObjectScopeAsync();
+            await func(jsonWriter);
+
+            Assert.True(rentVerified);
+        }
     }
 }

test/FunctionalTests/Microsoft.OData.Core.Tests/Json/JsonWriterTests.cs

@@ -7,8 +7,8 @@
 using System;
 using System.IO;
 using System.Text;
-using Microsoft.OData.Json;
 using Microsoft.OData.Edm;
+using Microsoft.OData.Json;
 using Xunit;
 
 namespace Microsoft.OData.Tests.Json
@@ -174,5 +174,35 @@ private void VerifyWriterPrimitiveValueWithIeee754Compatible<T>(T parameter, str
         }
 
         #endregion
+
+        [Fact]
+        public void WriteNameUsesProvidedCharArrayPool()
+        {
+            // Note: CharArrayPool is used if string has special chars
+            // This test is mostly theoretical since special characters are not allowed in names
+            SetupJsonWriterRunTestAndVerifyRent(
+                (jsonWriter) => jsonWriter.WriteName("foo\tbar"));
+        }
+
+        [Fact]
+        public void WriteStringValueUsesProvidedCharArrayPool()
+        {
+            SetupJsonWriterRunTestAndVerifyRent(
+                (jsonWriter) => jsonWriter.WriteValue("foo\tbar"));
+        }
+
+        private void SetupJsonWriterRunTestAndVerifyRent(Action<JsonWriter> action)
+        {
+            var jsonWriter = new JsonWriter(new StringWriter(builder), isIeee754Compatible: true);
+            bool rentVerified = false;
+
+            Action<int> rentVerifier = (minSize) => { rentVerified = true; };
+            jsonWriter.ArrayPool = new MockCharArrayPool { RentVerifier = rentVerifier };
+
+            jsonWriter.StartObjectScope();
+            action(jsonWriter);
+
+            Assert.True(rentVerified);
+        }
     }
 }

test/FunctionalTests/Microsoft.OData.Core.Tests/Json/MockCharArrayPool.cs

@@ -0,0 +1,31 @@
+//---------------------------------------------------------------------
+// <copyright file="MockCharArrayPool.cs" company="Microsoft">
+//      Copyright (C) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+// </copyright>
+//---------------------------------------------------------------------
+
+using System;
+using Microsoft.OData.Buffers;
+
+namespace Microsoft.OData.Tests.Json
+{
+    public class MockCharArrayPool : ICharArrayPool
+    {
+        public Action<int> RentVerifier;
+        public Action<char[]> ReturnVerifier;
+
+        public char[] Rent(int minSize)
+        {
+            var charArray = new char[minSize];
+            RentVerifier(minSize);
+
+            return charArray;
+        }
+
+        public void Return(char[] array)
+        {
+            ReturnVerifier(array);
+            // Do nothing else
+        }
+    }
+}