Add KeyComparer

ICSharpCode.Decompiler/TypeSystem/DecompilerTypeSystem.cs

@@ -46,7 +46,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 			IUnresolvedAssembly mainAssembly = cecilLoader.LoadModule(moduleDefinition);
 			var referencedAssemblies = new List<IUnresolvedAssembly>();
 			var assemblyReferenceQueue = new Queue<AssemblyNameReference>(moduleDefinition.AssemblyReferences);
-			var processedAssemblyReferences = new HashSet<AssemblyNameReference>(AssemblyNameReferenceComparer.Instance);
+			var processedAssemblyReferences = new HashSet<AssemblyNameReference>(KeyComparer.Create((AssemblyNameReference reference) => reference.FullName));
 			while (assemblyReferenceQueue.Count > 0) {
 				var asmRef = assemblyReferenceQueue.Dequeue();
 				if (!processedAssemblyReferences.Add(asmRef))
@@ -68,25 +68,6 @@ namespace ICSharpCode.Decompiler.TypeSystem
 			context = new SimpleTypeResolveContext(compilation.MainAssembly);
 		}
 
-		class AssemblyNameReferenceComparer : IEqualityComparer<AssemblyNameReference>
-		{
-			public static readonly AssemblyNameReferenceComparer Instance = new AssemblyNameReferenceComparer();
-
-			public bool Equals(AssemblyNameReference x, AssemblyNameReference y)
-			{
-				if (x == y)
-					return true;
-				if (x == null || y == null)
-					return false;
-				return x.FullName.Equals(y.FullName);
-			}
-
-			public int GetHashCode(AssemblyNameReference obj)
-			{
-				return obj.FullName.GetHashCode();
-			}
-		}
-
 		public ICompilation Compilation {
 			get { return compilation; }
 		}

ICSharpCode.Decompiler/Util/KeyComparer.cs

@@ -0,0 +1,81 @@
+// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+
+namespace ICSharpCode.Decompiler.Util
+{
+	public static class KeyComparer
+	{
+		public static KeyComparer<TElement, TKey> Create<TElement, TKey>(Func<TElement, TKey> keySelector)
+		{
+			return new KeyComparer<TElement, TKey>(keySelector, Comparer<TKey>.Default, EqualityComparer<TKey>.Default);
+		}
+		
+		public static KeyComparer<TElement, TKey> Create<TElement, TKey>(Func<TElement, TKey> keySelector, IComparer<TKey> comparer, IEqualityComparer<TKey> equalityComparer)
+		{
+			return new KeyComparer<TElement, TKey>(keySelector, comparer, equalityComparer);
+		}
+		
+		public static IComparer<TElement> Create<TElement, TKey>(Func<TElement, TKey> keySelector, IComparer<TKey> comparer)
+		{
+			return new KeyComparer<TElement, TKey>(keySelector, comparer, EqualityComparer<TKey>.Default);
+		}
+		
+		public static IEqualityComparer<TElement> Create<TElement, TKey>(Func<TElement, TKey> keySelector, IEqualityComparer<TKey> equalityComparer)
+		{
+			return new KeyComparer<TElement, TKey>(keySelector, Comparer<TKey>.Default, equalityComparer);
+		}
+	}
+	
+	public class KeyComparer<TElement, TKey> : IComparer<TElement>, IEqualityComparer<TElement>
+	{
+		readonly Func<TElement, TKey> keySelector;
+		readonly IComparer<TKey> keyComparer;
+		readonly IEqualityComparer<TKey> keyEqualityComparer;
+		
+		public KeyComparer(Func<TElement, TKey> keySelector, IComparer<TKey> keyComparer, IEqualityComparer<TKey> keyEqualityComparer)
+		{
+			if (keySelector == null)
+				throw new ArgumentNullException("keySelector");
+			if (keyComparer == null)
+				throw new ArgumentNullException("keyComparer");
+			if (keyEqualityComparer == null)
+				throw new ArgumentNullException("keyEqualityComparer");
+			this.keySelector = keySelector;
+			this.keyComparer = keyComparer;
+			this.keyEqualityComparer = keyEqualityComparer;
+		}
+		
+		public int Compare(TElement x, TElement y)
+		{
+			return keyComparer.Compare(keySelector(x), keySelector(y));
+		}
+		
+		public bool Equals(TElement x, TElement y)
+		{
+			return keyEqualityComparer.Equals(keySelector(x), keySelector(y));
+		}
+		
+		public int GetHashCode(TElement obj)
+		{
+			return keyEqualityComparer.GetHashCode(keySelector(obj));
+		}
+	}
+}