* ContextStack.cs: Added argument check to Type indexer, avoiding a

NRE. Modify System.Int32 indexer to throw ArgumentOutOfRangeException
instead of ArgumentException. Reduce number of times that item count
must be obtained.
* ContextStackTest.cs: Added unit tests for indexers, and argument
(null) checks.

svn path=/trunk/mcs/; revision=135596

2 files changed, 28 insertions, 15 deletions

diff --git a/mcs/class/System/System.ComponentModel.Design.Serialization/ChangeLog b/mcs/class/System/System.ComponentModel.Design.Serialization/ChangeLog
index 3f705c8cadc..3d9e9f98d35 100755
--- a/mcs/class/System/System.ComponentModel.Design.Serialization/ChangeLog
+++ b/mcs/class/System/System.ComponentModel.Design.Serialization/ChangeLog
@@ -1,3 +1,10 @@
+2009-06-06  Gert Driesen  <drieseng@users.sourceforge.net>
+
+	* ContextStack.cs: Added argument check to Type indexer, avoiding a
+	NRE. Modify System.Int32 indexer to throw ArgumentOutOfRangeException
+	instead of ArgumentException. Reduce number of times that item count
+	must be obtained.
+
 2008-06-05  Ivan N. Zlatev  <contact@i-nz.net>
 
 	* ContextStack.cs: Also check for subclasses in the Type-based
diff --git a/mcs/class/System/System.ComponentModel.Design.Serialization/ContextStack.cs b/mcs/class/System/System.ComponentModel.Design.Serialization/ContextStack.cs
index 132e28447c8..31b238c969b 100755..100644
--- a/mcs/class/System/System.ComponentModel.Design.Serialization/ContextStack.cs
+++ b/mcs/class/System/System.ComponentModel.Design.Serialization/ContextStack.cs
@@ -47,18 +47,23 @@ namespace System.ComponentModel.Design.Serialization
 		}
 
 		public object Current {
-			get { 
-				if (_contextList.Count > 0)
-					return _contextList[_contextList.Count-1];
+			get {
+				int context_count = _contextList.Count;
+				if (context_count > 0)
+					return _contextList [context_count - 1];
 				return null;
 			}
 		}
 
 		public object this[Type type] {
 			get {
-				for (int i = _contextList.Count - 1; i >= 0; i--)
-					if (type.IsInstanceOfType (_contextList[i]))
- 						return _contextList[i];
+				if (type == null)
+					throw new ArgumentNullException ("type");
+				for (int i = _contextList.Count - 1; i >= 0; i--) {
+					object context = _contextList [i];
+					if (type.IsInstanceOfType (context))
+						return context;
+				}
 				return null;
 			}
 		}
@@ -66,9 +71,10 @@ namespace System.ComponentModel.Design.Serialization
 		public object this[int level] {
 			get {
 				if (level < 0)
-					throw new ArgumentException ("level has to be >= 0","level");
-				if (_contextList.Count > 0 && _contextList.Count > level)
-					return _contextList[_contextList.Count - 1 - level];
+					throw new ArgumentOutOfRangeException ("level");
+				int context_count = _contextList.Count;
+				if (context_count > 0 && context_count > level)
+					return _contextList [context_count - 1 - level];
 				return null;
 			}
 		}
@@ -76,11 +82,12 @@ namespace System.ComponentModel.Design.Serialization
 		public object Pop ()
 		{
 			object o = null;
-   			if (_contextList.Count > 0) {
-   				int lastItem = _contextList.Count - 1;
-   				o = _contextList[lastItem];
-   				_contextList.RemoveAt (lastItem);
-   			}
+			int context_count = _contextList.Count;
+			if (context_count > 0) {
+				int lastItem = context_count - 1;
+				o = _contextList [lastItem];
+				_contextList.RemoveAt (lastItem);
+			}
 			return o;
 		}
 
@@ -88,7 +95,6 @@ namespace System.ComponentModel.Design.Serialization
 		{
 			if (context == null)
 				throw new ArgumentNullException ("context");
-
 			_contextList.Add (context);
 		}