Use the string builder cache when possible

Author: pdelvo

StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/FileHeaderCodeFixProvider.cs

@@ -18,6 +18,7 @@ namespace StyleCop.Analyzers.DocumentationRules
     using Microsoft.CodeAnalysis.Formatting;
     using StyleCop.Analyzers.Helpers;
     using StyleCop.Analyzers.Settings.ObjectModel;
+    using Helpers.ObjectPools;
 
     /// <summary>
     /// Implements a code fix for file header diagnostics.
@@ -135,7 +136,7 @@ private static SyntaxNode ReplaceWellFormedMultiLineCommentHeader(Document docum
 
             // Pad line that used to be next to a /*
             triviaStringParts[0] = commentIndentation + interlinePadding + " " + triviaStringParts[0];
-            StringBuilder sb = new StringBuilder();
+            StringBuilder sb = StringBuilderPool.Allocate();
             var copyrightText = commentIndentation + interlinePadding + " " +
                 GetCopyrightText(commentIndentation + interlinePadding, settings.DocumentationRules.CopyrightText, newLineText);
             var newHeader = WrapInXmlComment(commentIndentation + interlinePadding, copyrightText, document.Name, settings, newLineText);
@@ -196,8 +197,7 @@ private static SyntaxNode ReplaceWellFormedMultiLineCommentHeader(Document docum
                 sb.Append((i == 0 ? string.Empty : newLineText) + lines[i].TrimEnd());
             }
 
-            var newTrivia = SyntaxFactory.SyntaxTrivia(SyntaxKind.MultiLineCommentTrivia, sb.ToString());
-
+            var newTrivia = SyntaxFactory.SyntaxTrivia(SyntaxKind.MultiLineCommentTrivia, StringBuilderPool.ReturnAndFree(sb));
             return root.WithLeadingTrivia(trivia.Replace(commentTrivia, newTrivia));
         }
 

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/FileHeaderHelpers.cs

@@ -10,6 +10,7 @@ namespace StyleCop.Analyzers.Helpers
     using System.Xml.Linq;
     using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CSharp;
+    using ObjectPools;
 
     /// <summary>
     /// Helper class used for working with file headers
@@ -30,7 +31,7 @@ internal static FileHeader ParseFileHeader(SyntaxNode root)
                 return FileHeader.MissingFileHeader;
             }
 
-            var sb = new StringBuilder();
+            var sb = StringBuilderPool.Allocate();
             var endOfLineCount = 0;
             var done = false;
             var fileHeaderStart = int.MaxValue;
@@ -92,6 +93,7 @@ internal static FileHeader ParseFileHeader(SyntaxNode root)
 
             if (fileHeaderStart > fileHeaderEnd)
             {
+                StringBuilderPool.Free(sb);
                 return FileHeader.MissingFileHeader;
             }
 
@@ -102,7 +104,7 @@ internal static FileHeader ParseFileHeader(SyntaxNode root)
                 sb.Remove(sb.Length - eolLength, eolLength);
             }
 
-            return new FileHeader(sb.ToString(), fileHeaderStart, fileHeaderEnd);
+            return new FileHeader(StringBuilderPool.ReturnAndFree(sb), fileHeaderStart, fileHeaderEnd);
         }
 
         /// <summary>
@@ -162,7 +164,7 @@ internal static XmlFileHeader ParseXmlFileHeader(SyntaxNode root)
 
         private static string ProcessSingleLineCommentsHeader(SyntaxTriviaList triviaList, int startIndex, out int fileHeaderStart, out int fileHeaderEnd)
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderPool.Allocate();
             var endOfLineCount = 0;
             var done = false;
 
@@ -212,12 +214,12 @@ private static string ProcessSingleLineCommentsHeader(SyntaxTriviaList triviaLis
             }
 
             sb.AppendLine("</root>");
-            return sb.ToString();
+            return StringBuilderPool.ReturnAndFree(sb);
         }
 
         private static string ProcessMultiLineCommentsHeader(SyntaxTrivia multiLineComment, out int fileHeaderStart, out int fileHeaderEnd)
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderPool.Allocate();
 
             // wrap the XML from the file header in a single root element to make XML parsing work.
             sb.AppendLine("<root>");
@@ -237,7 +239,7 @@ private static string ProcessMultiLineCommentsHeader(SyntaxTrivia multiLineComme
             }
 
             sb.AppendLine("</root>");
-            return sb.ToString();
+            return StringBuilderPool.ReturnAndFree(sb);
         }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/NameSyntaxHelpers.cs

@@ -7,6 +7,7 @@ namespace StyleCop.Analyzers.Helpers
     using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CSharp;
     using Microsoft.CodeAnalysis.CSharp.Syntax;
+    using ObjectPools;
 
     /// <summary>
     /// Class containing the extension methods for the <see cref="NameSyntax"/> class.
@@ -36,11 +37,11 @@ internal static string ToNormalizedString(this NameSyntax nameSyntax)
         /// <returns>The name contained in the <see cref="NameSyntax"/>, with its alias removed (if any).</returns>
         internal static string ToUnaliasedString(this NameSyntax nameSyntax)
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderPool.Allocate();
 
             BuildName(nameSyntax, sb, false);
 
-            return sb.ToString();
+            return StringBuilderPool.ReturnAndFree(sb);
         }
 
         private static void BuildName(NameSyntax nameSyntax, StringBuilder builder, bool includeAlias)

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/ObjectPools/Extensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
+// This code was copied from the Roslyn code base (and slightly modified)
 using System.Collections.Generic;
 using System.Text;
 

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/ObjectPools/ObjectPool.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
+// This code was copied from the Roslyn code base (and slightly modified)
 using System;
 using System.Diagnostics;
 using System.Threading;

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/ObjectPools/PooledObject.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
+// This code was copied from the Roslyn code base (and slightly modified)
 using System;
 using System.Collections.Generic;
 using System.Text;

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/XmlCommentHelper.cs

@@ -10,6 +10,7 @@ namespace StyleCop.Analyzers.Helpers
     using System.Text.RegularExpressions;
     using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CSharp.Syntax;
+    using ObjectPools;
 
     /// <summary>
     /// Provides helper methods to work with XML comments
@@ -170,14 +171,14 @@ internal static string GetText(XmlTextSyntax textElement, bool normalizeWhitespa
                 return null;
             }
 
-            StringBuilder stringBuilder = new StringBuilder();
+            StringBuilder stringBuilder = StringBuilderPool.Allocate();
 
             foreach (var item in textElement.TextTokens)
             {
                 stringBuilder.Append(item);
             }
 
-            string result = stringBuilder.ToString();
+            string result = StringBuilderPool.ReturnAndFree(stringBuilder);
             if (normalizeWhitespace)
             {
                 result = Regex.Replace(result, @"\s+", " ");

StyleCop.Analyzers/StyleCop.Analyzers/NamingRules/SA1310CodeFixProvider.cs

@@ -11,6 +11,7 @@ namespace StyleCop.Analyzers.NamingRules
     using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CodeActions;
     using Microsoft.CodeAnalysis.CodeFixes;
+    using Helpers.ObjectPools;
 
     /// <summary>
     /// Implements a code fix for <see cref="SA1310FieldNamesMustNotContainUnderscore"/>.
@@ -58,7 +59,7 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
 
         private static string BuildProposedName(string currentName)
         {
-            StringBuilder builder = new StringBuilder(currentName.Length);
+            StringBuilder builder = StringBuilderPool.Allocate();
 
             bool foundNonUnderscore = false;
             bool capitalizeNextLetter = false;
@@ -93,7 +94,7 @@ private static string BuildProposedName(string currentName)
                 capitalizeNextLetter = true;
             }
 
-            return builder.ToString();
+            return StringBuilderPool.ReturnAndFree(builder);
         }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1027CodeFixProvider.cs

@@ -15,6 +15,7 @@ namespace StyleCop.Analyzers.SpacingRules
     using Microsoft.CodeAnalysis.CodeFixes;
     using Microsoft.CodeAnalysis.Text;
     using StyleCop.Analyzers.Helpers;
+    using Helpers.ObjectPools;
 
     /// <summary>
     /// Implements a code fix for <see cref="SA1027TabsMustNotBeUsed"/>.
@@ -62,7 +63,7 @@ private static TextChange FixDiagnostic(IndentationOptions indentationOptions, S
 
             TextLine startLine = sourceText.Lines.GetLineFromPosition(span.Start);
             string text = sourceText.ToString(TextSpan.FromBounds(startLine.Start, span.End));
-            StringBuilder replacement = new StringBuilder(indentationOptions.TabSize * span.Length);
+            StringBuilder replacement = StringBuilderPool.Allocate();
             int column = 0;
             for (int i = 0; i < text.Length; i++)
             {
@@ -97,7 +98,7 @@ private static TextChange FixDiagnostic(IndentationOptions indentationOptions, S
                 }
             }
 
-            return new TextChange(span, replacement.ToString());
+            return new TextChange(span, StringBuilderPool.ReturnAndFree(replacement));
         }
 
         private class FixAll : DocumentBasedFixAllProvider