Editor context actions - explicitly setting EditorContext.Editor = null from ContextActionsRenderer when the ViewModel is discarded. Prevents leaks of reference to CodeEditorView when IContextActionProviders keep long-lived references to EditorContext. (thanks to Daniel!)

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/ContextActionsRenderer.cs

@@ -108,9 +108,12 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			this.popup.OpenAtLineStart(this.Editor);
 		}
 		
+		EditorActionsProvider lastActions;
+
 		ContextActionsBulbViewModel BuildPopupViewModel(ITextEditor editor)
 		{
 			var actionsProvider = ContextActionsService.Instance.GetAvailableActions(editor);
+			this.lastActions = actionsProvider;
 			return new ContextActionsBulbViewModel(actionsProvider);
 		}
 
@@ -130,6 +133,11 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			this.popup.IsDropdownOpen = false;
 			this.popup.IsHiddenActionsExpanded = false;
 			this.popup.ViewModel = null;
+			if (this.lastActions != null) {
+				// Clear the context to prevent memory leaks in case some users kept long-lived references to EditorContext
+				this.lastActions.EditorContext.Clear();
+				this.lastActions = null;
+			}
 		}
 		
 		void WorkbenchSingleton_Workbench_ViewClosed(object sender, ViewContentEventArgs e)
@@ -139,6 +147,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 				if (e.Content.PrimaryFileName == this.Editor.FileName) {
 					WorkbenchSingleton.Workbench.ViewClosed -= WorkbenchSingleton_Workbench_ViewClosed;
 					WorkbenchSingleton.Workbench.ActiveViewContentChanged -= WorkbenchSingleton_Workbench_ActiveViewContentChanged;
+					ClosePopup();
 				}
 			} catch {}
 		}

src/AddIns/Misc/SharpRefactoring/Project/SharpRefactoring.csproj

@@ -77,7 +77,6 @@
     <Compile Include="Src\ContextActions\CheckAssignmentCache.cs" />
     <Compile Include="Src\ContextActions\CheckAssignmentNull.cs" />
     <Compile Include="Src\ContextActions\CheckAssignmentNotNull.cs" />
-    <Compile Include="Src\ContextActions\DelegateAction.cs" />
     <Compile Include="Src\ContextActions\Extensions.cs" />
     <Compile Include="Src\ContextActions\FindTypeDeclarationsVisitor.cs" />
     <Compile Include="Src\ContextActions\GenerateMember.cs" />

src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/CacheClassAtCaret.cs

@@ -12,7 +12,8 @@ using ICSharpCode.SharpDevelop.Refactoring;
 namespace SharpRefactoring.ContextActions
 {
 	/// <summary>
-	/// Description of CacheClassAtCaret.
+	/// Caches information about the class at the caret in the editor.
+	/// Used by ContextActions.
 	/// </summary>
 	public class CacheClassAtCaret : IContextActionCache
 	{
@@ -50,7 +51,6 @@ namespace SharpRefactoring.ContextActions
 				return;
 			var c = this.Class;
 			
-			// TODO cache
 			var classDecls = context.GetClassDeclarationsOnCurrentLine().ToList();
 			this.IsCaretAtClassDeclaration = classDecls.Count == 1 && (classDecls[0].FullyQualifiedName == c.FullyQualifiedName);
 			

src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/DelegateAction.cs

@@ -1,30 +0,0 @@
-// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
-// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
-
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Windows;
-using ICSharpCode.NRefactory;
-using Ast = ICSharpCode.NRefactory.Ast;
-using ICSharpCode.SharpDevelop;
-using ICSharpCode.SharpDevelop.Dom;
-using ICSharpCode.SharpDevelop.Dom.NRefactoryResolver;
-using ICSharpCode.SharpDevelop.Editor;
-using ICSharpCode.SharpDevelop.Editor.AvalonEdit;
-using ICSharpCode.SharpDevelop.Refactoring;
-
-namespace SharpRefactoring.ContextActions
-{
-	public class DelegateAction : IContextAction
-	{
-		public string Title { get; set; }
-		public System.Action ExecuteAction { get; set; }
-	
-		public void Execute()
-		{
-			if (this.ExecuteAction != null)
-				this.ExecuteAction();
-		}
-	}
-}

src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheck.cs

@@ -12,6 +12,15 @@ namespace SharpRefactoring.ContextActions
 	/// </summary>
 	public abstract class ParamCheck : ContextAction
 	{
+		public override bool IsAvailable(EditorContext context)
+		{
+			var paramAtCaret = GetParameterAtCaret(context.CurrentSymbol);
+			if (paramAtCaret == null)
+				return false;
+			
+			return IsAvailable(paramAtCaret.ResolvedType);
+		}
+		
 		public LocalResolveResult GetParameterAtCaret(ResolveResult symbol)
 		{
 			LocalResolveResult param = symbol as LocalResolveResult;
@@ -21,18 +30,10 @@ namespace SharpRefactoring.ContextActions
 				return null;
 			if (!param.IsParameter)
 				return null;
+			// FIXME must be parameter definition, and method with body (not interface or abstract)
 			return param;
 		}
 			
-		public override bool IsAvailable(EditorContext context)
-		{
-			var paramAtCaret = GetParameterAtCaret(context.CurrentSymbol);
-			if (paramAtCaret == null)
-				return false;
-			
-			return IsAvailable(paramAtCaret.ResolvedType);
-		}
-			
 		public override void Execute(EditorContext context)
 		{
 			var paramAtCaret = GetParameterAtCaret(context.CurrentSymbol);

src/Main/Base/Project/Src/Services/RefactoringService/ContextActions/ContextAction.cs

@@ -19,17 +19,19 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 		
 		public abstract void Execute(EditorContext context);
 		
+		public EditorContext Context { get; private set; }
+		
 		public IEnumerable<IContextAction> GetAvailableActions(EditorContext context)
 		{
+			// re-initialize the context
 			this.Context = context;
 			if (this.IsAvailable(context))
 				yield return this;
 		}
 		
-		public EditorContext Context { get; private set; }
-		
 		public void Execute()
 		{
+			// context was re-initialized in GetAvailableActions
 			Execute(this.Context);
 		}
 	}

src/Main/Base/Project/Src/Services/RefactoringService/ContextActions/ContextActionsService.cs

@@ -54,12 +54,14 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 		}
 	}
 	
-	
+	/// <summary>
+	/// Returned by <see cref="ContextActionsService.GetAvailableActions()"></see>.
+	/// </summary>
 	public class EditorActionsProvider
 	{
 		ITextEditor editor { get; set; }
 		IList<IContextActionsProvider> providers { get; set; }
-		EditorContext context { get; set; }
+		public EditorContext EditorContext { get; set; }
 		
 		public EditorActionsProvider(ITextEditor editor, IList<IContextActionsProvider> providers)
 		{
@@ -70,7 +72,7 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			this.editor = editor;
 			this.providers = providers;
 			ParserService.ParseCurrentViewContent();
-			this.context = new EditorContext(editor);
+			this.EditorContext = new EditorContext(editor);
 		}
 		
 		public IEnumerable<IContextAction> GetVisibleActions()

src/Main/Base/Project/Src/Services/RefactoringService/ContextActions/EditorContext.cs

@@ -16,9 +16,9 @@ using ICSharpCode.SharpDevelop.Editor;
 namespace ICSharpCode.SharpDevelop.Refactoring
 {
 	/// <summary>
-	/// Helper class for <see cref="IContextActionsProvider.GetAvailableActions"></see>.
-	/// Never keep long-lived references to this class
-	/// - the AST serves as one-time cache and does not get updated when editor text changes.
+	/// Contains information about code around the caret in the editor - useful for implementing Context actions.
+	/// Do not keep your own references to EditorContext.
+	/// It serves as one-time cache and does not get updated when editor text changes.
 	/// </summary>
 	public class EditorContext
 	{
@@ -27,16 +27,16 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 		int CaretColumn { get; set; }
 		
 		/// <summary>
-		/// Language independent.
+		/// The expression at editor caret. Language independent.
 		/// </summary>
 		public ExpressionResult CurrentExpression { get; private set; }
 		/// <summary>
-		/// Language independent.
+		/// The resolved symbol at editor caret. Language independent.
 		/// </summary>
 		public ResolveResult CurrentSymbol { get; private set; }
 		
 		/// <summary>
-		/// Language independent.
+		/// ParseInformation for current file. Language independent.
 		/// </summary>
 		public ParseInformation CurrentParseInformation { get; private set; }
 		
@@ -49,22 +49,33 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			}
 		}
 		
+		/// <summary>
+		/// The editor line containing the caret.
+		/// </summary>
 		public IDocumentLine CurrentLine { get; private set; }
 		/// <summary>
-		/// Only available for C# and VB.
+		/// Parsed AST of the current editor line. Only available for C# and VB.
 		/// </summary>
 		public INode CurrentLineAST { get; private set; }
 		/// <summary>
-		/// Only available for C# and VB.
+		/// Parsed AST of the member containing the editor caret. Only available for C# and VB.
 		/// </summary>
 		public INode CurrentMemberAST { get; private set; }
 		/// <summary>
-		/// Only available for C# and VB.
+		/// Parsed AST of the element at editor caret. Only available for C# and VB.
 		/// </summary>
-		public INode CurrentElement { get; private set; }
+		INode CurrentElement { get; set; }
 		
 		NRefactoryResolver Resolver { get; set; }
 		
+		/// <summary>
+		/// Caches values shared by Context actions. Used in <see cref="GetCached"></see>
+		/// </summary>
+		Dictionary<Type, object> cachedValues = new Dictionary<Type, object>();
+		
+		/// <summary>
+		/// Fully initializes the EditorContext.
+		/// </summary>
 		public EditorContext(ITextEditor editor)
 		{
 			if (editor == null)
@@ -93,27 +104,43 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 //			DebugLog();
 		}
 		
-		void DebugLog()
+		/// <summary>
+		/// Do not call from your Context actions - used by SharpDevelop.
+		/// Sets contents of editor context to null to prevent memory leaks. Used in case users implementing IContextActionProvider
+		/// keep long-lived references to EditorContext even when warned not to do so.
+		/// </summary>
+		public void Clear()
 		{
-			ICSharpCode.Core.LoggingService.Debug(string.Format(
-				@"
+			this.Editor = null;
+			this.CurrentElement = null;
+			this.CurrentLineAST = null;
+			this.CurrentMemberAST = null;
+			this.CurrentParseInformation = null;
+			this.CurrentSymbol = null;
+			this.Resolver = null;
+			this.cachedValues.Clear();
+		}
 		
-	Context actions :
-	ExprAtCaret: {0}
-	----------------------
-	SymbolAtCaret: {1}
-	----------------------
-	CurrentLineAST: {2}
-	----------------------
-	AstNodeAtCaret: {3}
-	----------------------
-	CurrentMemberAST: {4}
-	----------------------",
-				CurrentExpression, CurrentSymbol, CurrentLineAST,
-				CurrentElement == null ? "" : CurrentElement.ToString().TakeStartEllipsis(400),
-				CurrentMemberAST == null ? "" : CurrentMemberAST.ToString().TakeStartEllipsis(400)));
+		/// <summary>
+		/// Gets cached value shared by context actions. Initializes a new value if not present.
+		/// </summary>
+		public T GetCached<T>() where T : IContextActionCache, new()
+		{
+			Type t = typeof(T);
+			if (cachedValues.ContainsKey(t)) {
+				return (T)cachedValues[t];
+			} else {
+				T cached = new T();
+				cached.Initialize(this);
+				cachedValues[t] = cached;
+				return cached;
+			}
 		}
 		
+		/// <summary>
+		/// Checks if the caret is exactly at AST node of given type (e.g. "if" of IfElseStatement).
+		/// If yes, returns it. If not, returns null.
+		/// </summary>
 		public TNode GetCurrentElement<TNode>() where TNode : class, INode
 		{
 			if (this.CurrentElement is TNode)
@@ -121,6 +148,10 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			return null;
 		}
 		
+		/// <summary>
+		/// Checks if caret is within AST node of given type (e.g. anywhere inside IfElseStatement).
+		/// If yes, returns it. If not, returns null.
+		/// </summary>
 		public TNode GetContainingElement<TNode>() where TNode : class, INode
 		{
 			var node = this.CurrentElement;
@@ -133,22 +164,28 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			return null;
 		}
 		
-		Dictionary<Type, object> cachedValues = new Dictionary<Type, object>();
-		
-		public T GetCached<T>() where T : IContextActionCache, new()
+		void DebugLog()
 		{
-			Type t = typeof(T);
-			if (cachedValues.ContainsKey(t)) {
-				return (T)cachedValues[t];
-			} else {
-				T cached = new T();
-				cached.Initialize(this);
-				cachedValues[t] = cached;
-				return cached;
-			}
+			ICSharpCode.Core.LoggingService.Debug(string.Format(
+				@"
+	
+	Context actions :
+	ExprAtCaret: {0}
+	----------------------
+	SymbolAtCaret: {1}
+	----------------------
+	CurrentLineAST: {2}
+	----------------------
+	AstNodeAtCaret: {3}
+	----------------------
+	CurrentMemberAST: {4}
+	----------------------",
+				CurrentExpression, CurrentSymbol, CurrentLineAST,
+				CurrentElement == null ? "" : CurrentElement.ToString().TakeStartEllipsis(400),
+				CurrentMemberAST == null ? "" : CurrentMemberAST.ToString().TakeStartEllipsis(400)));
 		}
 		
-		public static INode FindInnermostNode(INode node, Location position)
+		static INode FindInnermostNode(INode node, Location position)
 		{
 			if (node == null)
 				return null;
@@ -214,12 +251,7 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			var snippetParser = GetSnippetParser(editor);
 			if (snippetParser == null)
 				return null;
-			//try	{
 			return snippetParser.Parse(currentLine.Text);
-			//}
-			//catch {
-			//	return null;
-			//}
 		}
 		
 		SnippetParser GetSnippetParser(ITextEditor editor)
@@ -245,14 +277,10 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 		
 		INode GetCurrentMemberAST(ITextEditor editor)
 		{
-			//try {
 			var resolver = GetInitializedNRefactoryResolver(editor, this.CaretLine, this.CaretColumn);
 			if (resolver == null)
 				return null;
 			return resolver.ParseCurrentMember(editor.Document.Text);
-			//} catch {
-			//	return null;
-			//}
 		}
 		
 		NRefactoryResolver GetInitializedNRefactoryResolver(ITextEditor editor, int caretLine, int caretColumn)

src/Main/Base/Project/Src/Services/RefactoringService/ContextActions/IContextAction.cs

@@ -7,11 +7,17 @@ using System.Windows;
 namespace ICSharpCode.SharpDevelop.Refactoring
 {
 	/// <summary>
-	/// Description of ContextAction.
+	/// One editor Context action.
 	/// </summary>
 	public interface IContextAction
 	{
+		/// <summary>
+		/// Title displayed in the context actions popup.
+		/// </summary>
 		string Title { get; }
+		/// <summary>
+		/// Executes this action. Called when this action is selected from the context actions popup.
+		/// </summary>
 		void Execute();
 	}
 }

src/Main/Base/Project/Src/Services/RefactoringService/ContextActions/IContextActionCache.cs

@@ -6,7 +6,7 @@ using System;
 namespace ICSharpCode.SharpDevelop.Refactoring
 {
 	/// <summary>
-	/// Data shared by multiple Context actions. Stored in EditorContext.GetCached().
+	/// Temporary data shared by multiple Context actions. Stored in EditorContext.GetCached().
 	/// </summary>
 	public interface IContextActionCache
 	{