Added support for LRUMap with a size of zero.

Signed-off-by: Eamon Hetherton <[email protected]>

Author: EamonHetherton

src/NHibernate.Test/UtilityTest/LRUMapFixture.cs

@@ -80,6 +80,17 @@ public void GetEntrySet()
 			{
 				Assert.AreNotEqual(-1, entry.Value.ToString().IndexOf("data:"));
 			}
-		}    
+		}
+
+		[Test]
+		public void PutWithSizeLimitOfZero()
+		{
+			IDictionary cache = new LRUMap(0);
+
+			cache.Add("key", "data");
+
+			string data = (string)cache["key"];
+			Assert.IsNull(data, "Data is wrong.");
+		}
 	}
 }

src/NHibernate/Util/LRUMap.cs

@@ -56,6 +56,10 @@ public override object this[object key]
 
 		public override void Add(object key, object value)
 		{
+			if (maximumSize == 0)
+			{
+				return;
+			}
 			int mapSize = Count;
 			if (mapSize >= maximumSize)
 			{
@@ -74,6 +78,10 @@ public override void Add(object key, object value)
 		private void RemoveLRU()
 		{
 			object key = FirstKey;
+			if (ReferenceEquals(null, key))
+			{
+				return;
+			}
 			// be sure to call super.get(key), or you're likely to 
 			// get infinite promotion recursion
 			object value = base[key];