Prevent potential stack overflow in ElementReturnType.BaseType.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/3.0@3896 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Main/ICSharpCode.SharpDevelop.Dom/Project/ICSharpCode.SharpDevelop.Dom.csproj

@@ -62,6 +62,7 @@
     <Compile Include="..\..\GlobalAssemblyInfo.cs">
       <Link>Configuration\GlobalAssemblyInfo.cs</Link>
     </Compile>
+    <Compile Include="Src\BusyManager.cs" />
     <Compile Include="Src\CSharp\OverloadResolution.cs" />
     <Compile Include="Src\CSharp\TypeInference.cs" />
     <Compile Include="Src\DomCache.cs" />

src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/BusyManager.cs

@@ -0,0 +1,56 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <author name="Daniel Grunwald"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections.Generic;
+
+namespace ICSharpCode.SharpDevelop.Dom
+{
+	/// <summary>
+	/// This class is used to prevent stack overflows by representing a 'busy' flag
+	/// that prevents reentrance when another call is running.
+	/// However, using a simple 'bool busy' is not thread-safe, so we use a
+	/// thread-static BusyManager.
+	/// </summary>
+	sealed class BusyManager
+	{
+		public struct BusyLock : IDisposable
+		{
+			public static readonly BusyLock Failed = new BusyLock(null);
+			
+			readonly BusyManager manager;
+			
+			public BusyLock(BusyManager manager)
+			{
+				this.manager = manager;
+			}
+			
+			public bool Success {
+				get { return manager != null; }
+			}
+			
+			public void Dispose()
+			{
+				if (manager != null) {
+					manager.activeObjects.RemoveAt(manager.activeObjects.Count - 1);
+				}
+			}
+		}
+		
+		readonly List<object> activeObjects = new List<object>();
+		
+		public BusyLock Enter(object obj)
+		{
+			for (int i = 0; i < activeObjects.Count; i++) {
+				if (activeObjects[i] == obj)
+					return BusyLock.Failed;
+			}
+			activeObjects.Add(obj);
+			return new BusyLock(this);
+		}
+	}
+}

src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Implementations/ElementReturnType.cs

@@ -28,24 +28,35 @@ namespace ICSharpCode.SharpDevelop.Dom
 			this.pc = pc;
 		}
 		
+		[ThreadStatic] static BusyManager _busyManager;
+		
+		static BusyManager busyManager {
+			get { return _busyManager ?? (_busyManager = new BusyManager()); }
+		}
+		
 		public override IReturnType BaseType {
 			get {
-				// get element type from enumerableType
-				if (enumerableType.IsArrayReturnType)
-					return enumerableType.CastToArrayReturnType().ArrayElementType;
-				
-				IClass c = enumerableType.GetUnderlyingClass();
-				if (c == null)
+				using (var l = busyManager.Enter(this)) {
+					if (!l.Success)
+						return null;
+					
+					// get element type from enumerableType
+					if (enumerableType.IsArrayReturnType)
+						return enumerableType.CastToArrayReturnType().ArrayElementType;
+					
+					IClass c = enumerableType.GetUnderlyingClass();
+					if (c == null)
+						return null;
+					IClass genumerable = pc.GetClass("System.Collections.Generic.IEnumerable", 1);
+					if (c.IsTypeInInheritanceTree(genumerable)) {
+						return MemberLookupHelper.GetTypeParameterPassedToBaseClass(enumerableType, genumerable, 0);
+					}
+					IClass enumerable = pc.GetClass("System.Collections.IEnumerable", 0);
+					if (c.IsTypeInInheritanceTree(enumerable)) {
+						return pc.SystemTypes.Object;
+					}
 					return null;
-				IClass genumerable = pc.GetClass("System.Collections.Generic.IEnumerable", 1);
-				if (c.IsTypeInInheritanceTree(genumerable)) {
-					return MemberLookupHelper.GetTypeParameterPassedToBaseClass(enumerableType, genumerable, 0);
-				}
-				IClass enumerable = pc.GetClass("System.Collections.IEnumerable", 0);
-				if (c.IsTypeInInheritanceTree(enumerable)) {
-					return pc.SystemTypes.Object;
 				}
-				return null;
 			}
 		}
 		

src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Implementations/ProxyReturnType.cs

@@ -33,17 +33,17 @@ namespace ICSharpCode.SharpDevelop.Dom
 				return true;
 			
 			IReturnType baseType = BaseType;
-			bool tmp = (baseType != null && TryEnter()) ? baseType.Equals(other) : false;
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.Equals(other) : false;
+			}
 		}
 		
 		public override int GetHashCode()
 		{
 			IReturnType baseType = BaseType;
-			int tmp = (baseType != null && TryEnter()) ? baseType.GetHashCode() : 0;
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetHashCode() : 0;
+			}
 		}
 		
 		protected int GetObjectHashCode()
@@ -52,121 +52,103 @@ namespace ICSharpCode.SharpDevelop.Dom
 		}
 		
 		// Required to prevent stack overflow on inferrence cycles
-		bool busy;
-		
-		// keep this method as small as possible, it should be inlined!
-		bool TryEnter()
-		{
-			if (busy) {
-				PrintTryEnterWarning();
-				return false;
-			} else {
-				busy = true;
-				return true;
-			}
-		}
-		
-		void Leave()
-		{
-			busy = false;
-		}
+		[ThreadStatic] static BusyManager _busyManager;
 		
-		void PrintTryEnterWarning()
-		{
-			LoggingService.Info("TryEnter failed on " + ToString());
+		static BusyManager busyManager {
+			get { return _busyManager ?? (_busyManager = new BusyManager()); }
 		}
 		
 		public virtual string FullyQualifiedName {
 			get {
 				IReturnType baseType = BaseType;
-				string tmp = (baseType != null && TryEnter()) ? baseType.FullyQualifiedName : "?";
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.FullyQualifiedName : "?";
+				}
 			}
 		}
 		
 		public virtual string Name {
 			get {
 				IReturnType baseType = BaseType;
-				string tmp = (baseType != null && TryEnter()) ? baseType.Name : "?";
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.Name : "?";
+				}
 			}
 		}
 		
 		public virtual string Namespace {
 			get {
 				IReturnType baseType = BaseType;
-				string tmp = (baseType != null && TryEnter()) ? baseType.Namespace : "?";
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.Namespace : "?";
+				}
 			}
 		}
 		
 		public virtual string DotNetName {
 			get {
 				IReturnType baseType = BaseType;
-				string tmp = (baseType != null && TryEnter()) ? baseType.DotNetName : "?";
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.DotNetName : "?";
+				}
 			}
 		}
 		
 		public virtual int TypeArgumentCount {
 			get {
 				IReturnType baseType = BaseType;
-				int tmp = (baseType != null && TryEnter()) ? baseType.TypeArgumentCount : 0;
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.TypeArgumentCount : 0;
+				}
 			}
 		}
 		
 		public virtual IClass GetUnderlyingClass()
 		{
 			IReturnType baseType = BaseType;
-			IClass tmp = (baseType != null && TryEnter()) ? baseType.GetUnderlyingClass() : null;
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetUnderlyingClass() : null;
+			}
 		}
 		
 		public virtual List<IMethod> GetMethods()
 		{
 			IReturnType baseType = BaseType;
-			List<IMethod> tmp = (baseType != null && TryEnter()) ? baseType.GetMethods() : new List<IMethod>();
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetMethods() : new List<IMethod>();
+			}
 		}
 		
 		public virtual List<IProperty> GetProperties()
 		{
 			IReturnType baseType = BaseType;
-			List<IProperty> tmp = (baseType != null && TryEnter()) ? baseType.GetProperties() : new List<IProperty>();
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetProperties() : new List<IProperty>();
+			}
 		}
 		
 		public virtual List<IField> GetFields()
 		{
 			IReturnType baseType = BaseType;
-			List<IField> tmp = (baseType != null && TryEnter()) ? baseType.GetFields() : new List<IField>();
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetFields() : new List<IField>();
+			}
 		}
 		
 		public virtual List<IEvent> GetEvents()
 		{
 			IReturnType baseType = BaseType;
-			List<IEvent> tmp = (baseType != null && TryEnter()) ? baseType.GetEvents() : new List<IEvent>();
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetEvents() : new List<IEvent>();
+			}
 		}
 		
 		public virtual bool IsDefaultReturnType {
 			get {
 				IReturnType baseType = BaseType;
-				bool tmp = (baseType != null && TryEnter()) ? baseType.IsDefaultReturnType : false;
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.IsDefaultReturnType : false;
+				}
 			}
 		}
 		
@@ -178,13 +160,9 @@ namespace ICSharpCode.SharpDevelop.Dom
 		public virtual T CastToDecoratingReturnType<T>() where T : DecoratingReturnType
 		{
 			IReturnType baseType = BaseType;
-			T temp;
-			if (baseType != null && TryEnter())
-				temp = baseType.CastToDecoratingReturnType<T>();
-			else
-				temp = null;
-			Leave();
-			return temp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.CastToDecoratingReturnType<T>() : null;
+			}
 		}
 		
 		
@@ -221,18 +199,18 @@ namespace ICSharpCode.SharpDevelop.Dom
 		public virtual bool? IsReferenceType {
 			get {
 				IReturnType baseType = BaseType;
-				bool? tmp = (baseType != null && TryEnter()) ? baseType.IsReferenceType : null;
-				Leave();
-				return tmp;
+				using (var l = busyManager.Enter(this)) {
+					return (l.Success && baseType != null) ? baseType.IsReferenceType : null;
+				}
 			}
 		}
 		
 		public virtual IReturnType GetDirectReturnType()
 		{
 			IReturnType baseType = BaseType;
-			IReturnType tmp = (baseType != null && TryEnter()) ? baseType.GetDirectReturnType() : UnknownReturnType.Instance;
-			Leave();
-			return tmp;
+			using (var l = busyManager.Enter(this)) {
+				return (l.Success && baseType != null) ? baseType.GetDirectReturnType() : UnknownReturnType.Instance;
+			}
 		}
 	}
 }