Merge pull request #119 from bkoelman/native-methods

Adds exception for platform invoke wrappers to AV1008

Author: bkoelman

src/CSharpGuidelinesAnalyzer/CSharpGuidelinesAnalyzer.Test/Specs/ClassDesign/AvoidStaticClassSpecs.cs

@@ -319,6 +319,37 @@ static void Main(string[] args)
             VerifyGuidelineDiagnostic(source);
         }
 
+        [Fact]
+        internal void When_static_class_is_platform_invoke_wrapper_it_must_be_skipped()
+        {
+            // Arrange
+            ParsedSourceCode source = new TypeSourceCodeBuilder()
+                .InGlobalScope(@"
+                    static class NativeMethods
+                    {
+                    }
+
+                    static class SafeNativeMethods
+                    {
+                    }
+
+                    static class UnsafeNativeMethods
+                    {
+                    }
+
+                    public class Wrapper
+                    {
+                        private static class NativeMethods
+                        {
+                        } 
+                    }
+                ")
+                .Build();
+
+            // Act and assert
+            VerifyGuidelineDiagnostic(source);
+        }
+
         protected override DiagnosticAnalyzer CreateAnalyzer()
         {
             return new AvoidStaticClassAnalyzer();

src/CSharpGuidelinesAnalyzer/CSharpGuidelinesAnalyzer/Rules/ClassDesign/AvoidStaticClassAnalyzer.cs

@@ -41,6 +41,10 @@ public sealed class AvoidStaticClassAnalyzer : DiagnosticAnalyzer
         private static readonly Action<SymbolAnalysisContext> AnalyzeNamedTypeAction = context =>
             context.SkipEmptyName(AnalyzeNamedType);
 
+        [ItemNotNull]
+        private static readonly ImmutableArray<string> PlatformInvokeWrapperTypeNames =
+            ImmutableArray.Create("NativeMethods", "SafeNativeMethods", "UnsafeNativeMethods");
+
         [ItemNotNull]
         public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create(TypeRule, MemberRule);
 
@@ -56,7 +60,7 @@ private static void AnalyzeNamedType(SymbolAnalysisContext context)
         {
             var type = (INamedTypeSymbol)context.Symbol;
 
-            if (!type.IsStatic || type.IsSynthesized())
+            if (!type.IsStatic || type.IsSynthesized() || IsPlatformInvokeWrapper(type))
             {
                 return;
             }
@@ -74,6 +78,11 @@ private static void AnalyzeNamedType(SymbolAnalysisContext context)
             }
         }
 
+        private static bool IsPlatformInvokeWrapper([NotNull] INamedTypeSymbol type)
+        {
+            return PlatformInvokeWrapperTypeNames.Contains(type.Name);
+        }
+
         private static bool TypeContainsEntryPoint([NotNull] INamedTypeSymbol type, [NotNull] Compilation compilation,
             CancellationToken cancellationToken)
         {