Cache expressions (third attempt)

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@4767 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/Misc/Debugger/Debugger.Core/Project/Src/Control/Process-StateControl.cs

@@ -5,6 +5,7 @@
 //     <version>$Revision$</version>
 // </file>
 
+using ICSharpCode.NRefactory.Ast;
 using System;
 using System.Collections.Generic;
 
@@ -16,6 +17,7 @@ namespace Debugger
 	{
 		internal bool TerminateCommandIssued = false;
 		internal Queue<Breakpoint> BreakpointHitEventQueue = new Queue<Breakpoint>();
+		internal Dictionary<INode, Value> CachedExpressions = new Dictionary<INode, Value>();
 		
 		#region Events
 		
@@ -99,6 +101,7 @@ namespace Debugger
 			if (action == DebuggeeStateAction.Clear) {
 				if (debuggeeState == null) throw new DebuggerException("Debugee state already cleared");
 				debuggeeState = null;
+				this.CachedExpressions.Clear();
 			}
 		}
 		

src/AddIns/Misc/Debugger/Debugger.Core/Project/Src/Expressions/ExpressionEvaluator.cs

@@ -100,10 +100,17 @@ namespace Debugger
 		
 		public Value Evaluate(INode expression, bool permRef)
 		{
+			// Try to get the value from cache
+			// (the cache is cleared when the process is resumed)
+			Value val;
+			if (context.Process.CachedExpressions.TryGetValue(expression, out val)) {
+				if (val == null || !val.IsInvalid) {
+					return val;
+				}
+			}
+			
 			Stopwatch watch = new Stopwatch();
 			watch.Start();
-			
-			Value val;
 			try {
 				val = (Value)expression.AcceptVisitor(this, null);
 				if (val != null && permRef)
@@ -117,6 +124,9 @@ namespace Debugger
 				context.Process.TraceMessage("Evaluated: {0} in {1} ms total", expression.PrettyPrint(), watch.ElapsedMilliseconds);
 			}
 			
+			// Add the result to cache
+			context.Process.CachedExpressions[expression] = val;
+			
 			return val;
 		}
 		

src/AddIns/Misc/Debugger/Debugger.Core/Project/Src/Expressions/ExpressionExtensionMethods.cs

@@ -58,6 +58,7 @@ namespace Debugger
 		
 		public static string PrettyPrint(this INode code)
 		{
+			if (code == null) return string.Empty;
 			CSharpOutputVisitor csOutVisitor = new CSharpOutputVisitor();
 			code.AcceptVisitor(csOutVisitor, null);
 			return csOutVisitor.Text;