reimplement CaretReferencesRenderer as IBackgroundRenderer

fix #368, fix #372

Author: siegfriedpammer

src/AddIns/BackendBindings/CSharpBinding/Project/CSharpBinding.csproj

@@ -68,6 +68,9 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Configuration\AssemblyInfo.cs" />
+    <Compile Include="Src\CaretReferenceHighlightRenderer.cs">
+      <DependentUpon>CSharpSemanticHighlighter.cs</DependentUpon>
+    </Compile>
     <Compile Include="Src\CodeManipulation.cs" />
     <Compile Include="Src\Completion\CSharpCompletionContext.cs" />
     <Compile Include="Src\Completion\CSharpInsightItem.cs" />
@@ -80,6 +83,9 @@
     <Compile Include="Src\Completion\SegmentTrackingOutputFormatter.cs" />
     <Compile Include="Src\Completion\TypeCompletionData.cs" />
     <Compile Include="Src\Completion\XmlDocCompletionData.cs" />
+    <Compile Include="Src\CSharpSemanticHighlighterVisitor.cs">
+      <DependentUpon>CSharpSemanticHighlighter.cs</DependentUpon>
+    </Compile>
     <Compile Include="Src\FormattingStrategy\CSharpFormatter.cs" />
     <Compile Include="Src\FormsDesigner\CSharpDesignerGenerator.cs" />
     <Compile Include="Src\FormsDesigner\CSharpDesignerLoader.cs" />

src/AddIns/BackendBindings/CSharpBinding/Project/Src/CSharpLanguageBinding.cs

@@ -61,15 +61,14 @@ public class CSharpTextEditorExtension : ITextEditorExtension
 		IssueManager inspectionManager;
 		IList<IContextActionProvider> contextActionProviders;
 		CodeManipulation codeManipulation;
-		CSharpSemanticHighlighter highlighter;
-		CancellationTokenSource caretMovementTokenSource;
+		CaretReferenceHighlightRenderer renderer;
 
 		public void Attach(ITextEditor editor)
 		{
 			this.editor = editor;
 			inspectionManager = new IssueManager(editor);
 			codeManipulation = new CodeManipulation(editor);
-			this.editor.Caret.LocationChanged += CaretLocationChanged;
+			renderer = new CaretReferenceHighlightRenderer(editor);
 
 			if (!editor.ContextActionProviders.IsReadOnly) {
 				contextActionProviders = AddInTree.BuildItems<IContextActionProvider>("/SharpDevelop/ViewContent/TextEditor/C#/ContextActions", null);
@@ -87,21 +86,8 @@ public void Detach()
 			if (contextActionProviders != null) {
 				editor.ContextActionProviders.RemoveAll(contextActionProviders.Contains);
 			}
-			this.editor.Caret.LocationChanged -= CaretLocationChanged;
+			renderer.Dispose();
 			this.editor = null;
 		}
-
-		void CaretLocationChanged(object sender, EventArgs e)
-		{
-			if (highlighter == null)
-				highlighter = editor.GetService<CSharpSemanticHighlighter>();
-			if (highlighter == null)
-				return;
-			if (caretMovementTokenSource != null)
-				caretMovementTokenSource.Cancel();
-			caretMovementTokenSource = new CancellationTokenSource();
-			var rr = SD.ParserService.Resolve(editor.FileName, editor.Caret.Location, editor.Document, cancellationToken: caretMovementTokenSource.Token);
-			highlighter.SetCurrentSymbol(rr.GetSymbol());
-		}
 	}
 }