Improve performance of IsPrecededByWhitespace

pdelvo · pdelvo · commit 9ba46cd669bc · 2016-01-22T19:54:12.000+01:00
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/Helpers/TokenHelper.cs b/StyleCop.Analyzers/StyleCop.Analyzers/Helpers/TokenHelper.cs
@@ -3,6 +3,7 @@
 
 namespace StyleCop.Analyzers.Helpers
 {
+    using System.Threading;
     using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CSharp;
 
@@ -61,17 +62,19 @@ internal static bool IsLastInLine(this SyntaxToken token)
         /// Gets a value indicating whether the <paramref name="token"/> is preceded by a whitespace.
         /// </summary>
         /// <param name="token">The token to process.</param>
+        /// <param name="cancellationToken">A <see cref="CancellationToken"/>.</param>
         /// <returns>true if token is preceded by a whitespace, otherwise false.</returns>
-        internal static bool IsPrecededByWhitespace(this SyntaxToken token)
+        internal static bool IsPrecededByWhitespace(this SyntaxToken token, CancellationToken cancellationToken)
         {
-            SyntaxTriviaList triviaList = token.LeadingTrivia;
-            if (triviaList.Count > 0)
+            // Perf directly access the text instead of trivia
+            int pos = token.Span.Start - 1;
+
+            if (pos < 0 || token.SyntaxTree == null)
             {
-                return triviaList.Last().IsKind(SyntaxKind.WhitespaceTrivia);
+                return false;
             }
 
-            triviaList = token.GetPreviousToken().TrailingTrivia;
-            return triviaList.Count > 0 && triviaList.Last().IsKind(SyntaxKind.WhitespaceTrivia);
+            return char.IsWhiteSpace(token.SyntaxTree.GetText(cancellationToken)[pos]);
         }
 
         /// <summary>
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1001CommasMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1001CommasMustBeSpacedCorrectly.cs
@@ -99,7 +99,7 @@ private static void HandleCommaToken(SyntaxTreeAnalysisContext context, SyntaxTo
                 }
             }
 
-            if (token.IsFirstInLine() || token.IsPrecededByWhitespace())
+            if (token.IsFirstInLine() || token.IsPrecededByWhitespace(context.CancellationToken))
             {
                 // comma must{ not} be {preceded} by whitespace
                 context.ReportDiagnostic(Diagnostic.Create(Descriptor, token.GetLocation(), TokenSpacingProperties.RemovePrecedingPreserveLayout, " not", "preceded"));
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1009ClosingParenthesisMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1009ClosingParenthesisMustBeSpacedCorrectly.cs
@@ -79,7 +79,7 @@ private static void HandleCloseParenToken(SyntaxTreeAnalysisContext context, Syn
                 return;
             }
 
-            bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace();
+            bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace(context.CancellationToken);
             bool followedBySpace = token.IsFollowedByWhitespace();
             bool lastInLine = token.IsLastInLine();
             bool precedesStickyCharacter;
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1010OpeningSquareBracketsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1010OpeningSquareBracketsMustBeSpacedCorrectly.cs
@@ -79,7 +79,7 @@ private static void HandleOpenBracketToken(SyntaxTreeAnalysisContext context, Sy
 
             if (!firstInLine)
             {
-                precededBySpace = token.IsPrecededByWhitespace();
+                precededBySpace = token.IsPrecededByWhitespace(context.CancellationToken);
 
                 // ignore if handled by SA1026
                 ignorePrecedingSpaceProblem = precededBySpace && token.GetPreviousToken().IsKind(SyntaxKind.NewKeyword);
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1011ClosingSquareBracketsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1011ClosingSquareBracketsMustBeSpacedCorrectly.cs
@@ -85,7 +85,7 @@ private static void HandleCloseBracketToken(SyntaxTreeAnalysisContext context, S
             }
 
             bool firstInLine = token.IsFirstInLine();
-            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace();
+            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace(context.CancellationToken);
             bool followedBySpace = token.IsFollowedByWhitespace();
             bool lastInLine = token.IsLastInLine();
             bool precedesSpecialCharacter;
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1012OpeningBracesMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1012OpeningBracesMustBeSpacedCorrectly.cs
@@ -91,7 +91,7 @@ private static void HandleOpenBraceToken(SyntaxTreeAnalysisContext context, Synt
                 return;
             }
 
-            bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace();
+            bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace(context.CancellationToken);
 
             if (!precededBySpace)
             {
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1013ClosingBracesMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1013ClosingBracesMustBeSpacedCorrectly.cs
@@ -76,7 +76,7 @@ private static void HandleCloseBraceToken(SyntaxTreeAnalysisContext context, Syn
                 return;
             }
 
-            bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace();
+            bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace(context.CancellationToken);
 
             if (token.Parent is InterpolationSyntax)
             {
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1014OpeningGenericBracketsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1014OpeningGenericBracketsMustBeSpacedCorrectly.cs
@@ -84,7 +84,7 @@ private static void HandleLessThanToken(SyntaxTreeAnalysisContext context, Synta
             }
 
             bool firstInLine = token.IsFirstInLine();
-            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace();
+            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace(context.CancellationToken);
             bool followedBySpace = token.IsFollowedByWhitespace();
 
             if (!firstInLine && precededBySpace)
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1015ClosingGenericBracketsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1015ClosingGenericBracketsMustBeSpacedCorrectly.cs
@@ -87,7 +87,7 @@ private static void HandleGreaterThanToken(SyntaxTreeAnalysisContext context, Sy
 
             bool firstInLine = token.IsFirstInLine();
             bool lastInLine = token.IsLastInLine();
-            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace();
+            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace(context.CancellationToken);
             bool followedBySpace = token.IsFollowedByWhitespace();
             bool allowTrailingNoSpace;
             bool allowTrailingSpace;
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1019MemberAccessSymbolsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1019MemberAccessSymbolsMustBeSpacedCorrectly.cs
@@ -101,7 +101,7 @@ private static void HandleQuestionToken(SyntaxTreeAnalysisContext context, Synta
         private static void HandleMemberAccessSymbol(SyntaxTreeAnalysisContext context, SyntaxToken token)
         {
             bool firstInLine = token.IsFirstInLine();
-            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace();
+            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace(context.CancellationToken);
             bool followedBySpace = token.IsFollowedByWhitespace();
 
             if (!firstInLine && precededBySpace)
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1021NegativeSignsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1021NegativeSignsMustBeSpacedCorrectly.cs
@@ -93,7 +93,7 @@ private static void HandleMinusToken(SyntaxTreeAnalysisContext context, SyntaxTo
 
             if (!firstInLine)
             {
-                precededBySpace = token.IsPrecededByWhitespace();
+                precededBySpace = token.IsPrecededByWhitespace(context.CancellationToken);
                 SyntaxToken precedingToken = token.GetPreviousToken();
 
                 followsSpecialCharacter =
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1022PositiveSignsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1022PositiveSignsMustBeSpacedCorrectly.cs
@@ -93,7 +93,7 @@ private static void HandlePlusToken(SyntaxTreeAnalysisContext context, SyntaxTok
 
             if (!firstInLine)
             {
-                precededBySpace = token.IsPrecededByWhitespace();
+                precededBySpace = token.IsPrecededByWhitespace(context.CancellationToken);
                 SyntaxToken precedingToken = token.GetPreviousToken();
 
                 followsSpecialCharacter =
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1023DereferenceAndAccessOfSymbolsMustBeSpacedCorrectly.cs b/StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1023DereferenceAndAccessOfSymbolsMustBeSpacedCorrectly.cs
@@ -142,7 +142,7 @@ private static void HandleAsteriskToken(SyntaxTreeAnalysisContext context, Synta
             }
 
             bool firstInLine = token.IsFirstInLine();
-            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace();
+            bool precededBySpace = firstInLine || token.IsPrecededByWhitespace(context.CancellationToken);
             bool followedBySpace = token.IsFollowedByWhitespace();
             bool lastInLine = token.IsLastInLine();
 

Original file line number	Diff line number	Diff line change
`@@ -3,6 +3,7 @@`
`3`	`3`
`4`	`4`	`namespace StyleCop.Analyzers.Helpers`
`5`	`5`	`{`
	`6`	`+ using System.Threading;`
`6`	`7`	`using Microsoft.CodeAnalysis;`
`7`	`8`	`using Microsoft.CodeAnalysis.CSharp;`
`8`	`9`
`@@ -61,17 +62,19 @@ internal static bool IsLastInLine(this SyntaxToken token)`
`61`	`62`	`/// Gets a value indicating whether the <paramref name="token"/> is preceded by a whitespace.`
`62`	`63`	`/// </summary>`
`63`	`64`	`/// <param name="token">The token to process.</param>`
	`65`	`+ /// <param name="cancellationToken">A <see cref="CancellationToken"/>.</param>`
`64`	`66`	`/// <returns>true if token is preceded by a whitespace, otherwise false.</returns>`
`65`		`- internal static bool IsPrecededByWhitespace(this SyntaxToken token)`
	`67`	`+ internal static bool IsPrecededByWhitespace(this SyntaxToken token, CancellationToken cancellationToken)`
`66`	`68`	`{`
`67`		`- SyntaxTriviaList triviaList = token.LeadingTrivia;`
`68`		`- if (triviaList.Count > 0)`
	`69`	`+ // Perf directly access the text instead of trivia`
	`70`	`+ int pos = token.Span.Start - 1;`
	`71`	`+`
	`72`	`+ if (pos < 0 \|\| token.SyntaxTree == null)`
`69`	`73`	`{`
`70`		`- return triviaList.Last().IsKind(SyntaxKind.WhitespaceTrivia);`
	`74`	`+ return false;`
`71`	`75`	`}`
`72`	`76`
`73`		`- triviaList = token.GetPreviousToken().TrailingTrivia;`
`74`		`- return triviaList.Count > 0 && triviaList.Last().IsKind(SyntaxKind.WhitespaceTrivia);`
	`77`	`+ return char.IsWhiteSpace(token.SyntaxTree.GetText(cancellationToken)[pos]);`
`75`	`78`	`}`
`76`	`79`
`77`	`80`	`/// <summary>`
Original file line number	Diff line number	Diff line change
`@@ -99,7 +99,7 @@ private static void HandleCommaToken(SyntaxTreeAnalysisContext context, SyntaxTo`
`99`	`99`	`}`
`100`	`100`	`}`
`101`	`101`
`102`		`- if (token.IsFirstInLine() \|\| token.IsPrecededByWhitespace())`
	`102`	`+ if (token.IsFirstInLine() \|\| token.IsPrecededByWhitespace(context.CancellationToken))`
`103`	`103`	`{`
`104`	`104`	`// comma must{ not} be {preceded} by whitespace`
`105`	`105`	`context.ReportDiagnostic(Diagnostic.Create(Descriptor, token.GetLocation(), TokenSpacingProperties.RemovePrecedingPreserveLayout, " not", "preceded"));`
Original file line number	Diff line number	Diff line change
`@@ -79,7 +79,7 @@ private static void HandleCloseParenToken(SyntaxTreeAnalysisContext context, Syn`
`79`	`79`	`return;`
`80`	`80`	`}`
`81`	`81`
`82`		`- bool precededBySpace = token.IsFirstInLine() \|\| token.IsPrecededByWhitespace();`
	`82`	`+ bool precededBySpace = token.IsFirstInLine() \|\| token.IsPrecededByWhitespace(context.CancellationToken);`
`83`	`83`	`bool followedBySpace = token.IsFollowedByWhitespace();`
`84`	`84`	`bool lastInLine = token.IsLastInLine();`
`85`	`85`	`bool precedesStickyCharacter;`
Original file line number	Diff line number	Diff line change
`@@ -85,7 +85,7 @@ private static void HandleCloseBracketToken(SyntaxTreeAnalysisContext context, S`
`85`	`85`	`}`
`86`	`86`
`87`	`87`	`bool firstInLine = token.IsFirstInLine();`
`88`		`- bool precededBySpace = firstInLine \|\| token.IsPrecededByWhitespace();`
	`88`	`+ bool precededBySpace = firstInLine \|\| token.IsPrecededByWhitespace(context.CancellationToken);`
`89`	`89`	`bool followedBySpace = token.IsFollowedByWhitespace();`
`90`	`90`	`bool lastInLine = token.IsLastInLine();`
`91`	`91`	`bool precedesSpecialCharacter;`
Original file line number	Diff line number	Diff line change
`@@ -91,7 +91,7 @@ private static void HandleOpenBraceToken(SyntaxTreeAnalysisContext context, Synt`
`91`	`91`	`return;`
`92`	`92`	`}`
`93`	`93`
`94`		`- bool precededBySpace = token.IsFirstInLine() \|\| token.IsPrecededByWhitespace();`
	`94`	`+ bool precededBySpace = token.IsFirstInLine() \|\| token.IsPrecededByWhitespace(context.CancellationToken);`
`95`	`95`
`96`	`96`	`if (!precededBySpace)`
`97`	`97`	`{`
Original file line number	Diff line number	Diff line change
`@@ -76,7 +76,7 @@ private static void HandleCloseBraceToken(SyntaxTreeAnalysisContext context, Syn`
`76`	`76`	`return;`
`77`	`77`	`}`
`78`	`78`
`79`		`- bool precededBySpace = token.IsFirstInLine() \|\| token.IsPrecededByWhitespace();`
	`79`	`+ bool precededBySpace = token.IsFirstInLine() \|\| token.IsPrecededByWhitespace(context.CancellationToken);`
`80`	`80`
`81`	`81`	`if (token.Parent is InterpolationSyntax)`
`82`	`82`	`{`
Original file line number	Diff line number	Diff line change
`@@ -84,7 +84,7 @@ private static void HandleLessThanToken(SyntaxTreeAnalysisContext context, Synta`
`84`	`84`	`}`
`85`	`85`
`86`	`86`	`bool firstInLine = token.IsFirstInLine();`
`87`		`- bool precededBySpace = firstInLine \|\| token.IsPrecededByWhitespace();`
	`87`	`+ bool precededBySpace = firstInLine \|\| token.IsPrecededByWhitespace(context.CancellationToken);`
`88`	`88`	`bool followedBySpace = token.IsFollowedByWhitespace();`
`89`	`89`
`90`	`90`	`if (!firstInLine && precededBySpace)`
Original file line number	Diff line number	Diff line change
`@@ -101,7 +101,7 @@ private static void HandleQuestionToken(SyntaxTreeAnalysisContext context, Synta`
`101`	`101`	`private static void HandleMemberAccessSymbol(SyntaxTreeAnalysisContext context, SyntaxToken token)`
`102`	`102`	`{`
`103`	`103`	`bool firstInLine = token.IsFirstInLine();`
`104`		`- bool precededBySpace = firstInLine \|\| token.IsPrecededByWhitespace();`
	`104`	`+ bool precededBySpace = firstInLine \|\| token.IsPrecededByWhitespace(context.CancellationToken);`
`105`	`105`	`bool followedBySpace = token.IsFollowedByWhitespace();`
`106`	`106`
`107`	`107`	`if (!firstInLine && precededBySpace)`