NCBC-229: Add Remove with Cas method

Enyim.Caching/IMemcachedClient.cs

@@ -49,6 +49,7 @@ public interface IMemcachedClient : IDisposable
 		CasResult<ulong> Increment(string key, ulong defaultValue, ulong delta, TimeSpan validFor, ulong cas);
 
 		bool Remove(string key);
+		bool Remove(string key, ulong cas);
 
 		void FlushAll();
 

Enyim.Caching/IMemcachedResultsClient.cs

@@ -50,6 +50,7 @@ public interface IMemcachedResultsClient
 		IConcatOperationResult ExecutePrepend(string key, ulong cas, ArraySegment<byte> data);
 
 		IRemoveOperationResult ExecuteRemove(string key);
+		IRemoveOperationResult ExecuteRemove(string key, ulong cas);
 	}
 }
 

Enyim.Caching/Memcached/Results/StatusCodes/StatusCodeEnums.cs

@@ -8,7 +8,8 @@ namespace Enyim.Caching.Memcached.Results.StatusCodes
 	public enum StatusCodeEnums
 	{
 		Success = 0,
-		NotFound
+		NotFound,
+		DataExistsForKey
 	}
 }
 

Enyim.Caching/MemcachedClient.Results.cs

@@ -441,15 +441,25 @@ public IConcatOperationResult ExecutePrepend(string key, ulong cas, ArraySegment
 		/// </summary>
 		/// <param name="key">The identifier for the item to delete.</param>
 		/// <returns>true if the item was successfully removed from the cache; false otherwise.</returns>
+		public IRemoveOperationResult ExecuteRemove(string key, ulong cas)
+		{
+			return PerformRemove(key, cas);
+		}
+
 		public IRemoveOperationResult ExecuteRemove(string key)
+		{
+			return PerformRemove(key);
+		}
+
+		protected IRemoveOperationResult PerformRemove(string key, ulong cas = 0)
 		{
 			var hashedKey = this.keyTransformer.Transform(key);
 			var node = this.pool.Locate(hashedKey);
 			var result = RemoveOperationResultFactory.Create();
 
 			if (node != null)
 			{
-				var command = this.pool.OperationFactory.Delete(hashedKey, 0);
+				var command = this.pool.OperationFactory.Delete(hashedKey, cas);
 				var commandResult = node.Execute(command);
 
 				if (commandResult.Success)

Enyim.Caching/MemcachedClient.cs

@@ -783,6 +783,17 @@ public bool Remove(string key)
 			return ExecuteRemove(key).Success;
 		}
 
+		/// <summary>
+		/// Removes the specified item from the cache.
+		/// </summary>
+		/// <param name="key">The identifier for the item to delete.</param>
+		/// <param name="cas">The Cas value associated with the key</param>
+		/// <returns>true if the item was successfully removed from the cache; false otherwise.</returns>
+		public bool Remove(string key, ulong cas)
+		{
+			return ExecuteRemove(key, cas).Success;
+		}
+
 		/// <summary>
 		/// Retrieves multiple items from the cache.
 		/// </summary>