/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System;

namespace Lucene.Net.Store
{
	
	/// <summary>This class provides access to package-level features defined in the
	/// store package. It is used for testing only.
	/// </summary>
	public class _TestHelper
	{
		
		/// <summary>Returns true if the instance of the provided input stream is actually
		/// an FSIndexInput.
		/// </summary>
		public static bool IsFSIndexInput(IndexInput is_Renamed)
		{
			return is_Renamed is FSIndexInput;
		}
		
		/// <summary>Returns true if the provided input stream is an FSIndexInput and
		/// is a clone, that is it does not own its underlying file descriptor.
		/// </summary>
		public static bool IsFSIndexInputClone(IndexInput is_Renamed)
		{
			if (IsFSIndexInput(is_Renamed))
			{
				return ((FSIndexInput) is_Renamed).IsClone;
			}
			else
			{
				return false;
			}
		}
		
		/// <summary>Given an instance of FSDirectory.FSIndexInput, this method returns
		/// true if the underlying file descriptor is valid, and false otherwise.
		/// This can be used to determine if the OS file has been closed.
		/// The descriptor becomes invalid when the non-clone instance of the
		/// FSIndexInput that owns this descriptor is closed. However, the
		/// descriptor may possibly become invalid in other ways as well.
		/// </summary>
		public static bool IsFSIndexInputOpen(IndexInput is_Renamed)
		{
			if (IsFSIndexInput(is_Renamed))
			{
				FSIndexInput fis = (FSIndexInput) is_Renamed;
				return fis.IsFDValid();
			}
			else
			{
				return false;
			}
		}
	}
}