/* 
 * 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;
using System.Collections.Generic;

namespace Lucene.Net.Store
{
	
	[Serializable]
	public class RAMFile
	{
		
		private const long serialVersionUID = 1L;

        protected List<byte[]> buffers = new List<byte[]>();
		internal long length;
		internal RAMDirectory directory;
		internal long sizeInBytes; 
		
		// This is publicly modifiable via Directory.touchFile(), so direct access not supported
		private long lastModified = (DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond);
		
		// File used as buffer, in no RAMDirectory
		public /*internal*/ RAMFile()
		{
		}
		
		public /*internal*/ RAMFile(RAMDirectory directory)
		{
			this.directory = directory;
		}
		
		// For non-stream access from thread that might be concurrent with writing
		public /*internal*/ virtual long GetLength()
		{
			lock (this)
			{
				return length;
			}
		}
		
		public /*internal*/ virtual void  SetLength(long length)
		{
			lock (this)
			{
				this.length = length;
			}
		}
		
		// For non-stream access from thread that might be concurrent with writing
		internal virtual long GetLastModified()
		{
			lock (this)
			{
				return lastModified;
			}
		}
		
		internal virtual void  SetLastModified(long lastModified)
		{
			lock (this)
			{
				this.lastModified = lastModified;
			}
		}
		
		internal byte[] AddBuffer(int size)
		{
            byte[] buffer = NewBuffer(size);
            lock (this)
            {
                buffers.Add(buffer);
                sizeInBytes += size;
            }

            if (directory != null)
            {
                lock (directory) //{{DIGY}} what if directory gets null in the mean time?
                {
                    directory.sizeInBytes += size;
                }
            }

            return buffer;
		}
		
		public /*internal*/ byte[] GetBuffer(int index)
		{
			lock (this)
			{
				return (byte[]) buffers[index];
			}
		}
		
		public /*internal*/ int NumBuffers()
		{
			lock (this)
			{
				return buffers.Count;
			}
		}
		
		/// <summary> Expert: allocate a new buffer. 
		/// Subclasses can allocate differently. 
		/// </summary>
		/// <param name="size">size of allocated buffer.
		/// </param>
		/// <returns> allocated buffer.
		/// </returns>
		public /*internal*/ virtual byte[] NewBuffer(int size)
		{
			return new byte[size];
		}
		
		
		public /*internal*/ virtual long GetSizeInBytes()
		{
            lock (this)
            {
                return sizeInBytes;
            }
		}

        public long length_ForNUnit
        {
            get { return length; }
        }

        public RAMDirectory directory_ForNUnit
        {
            get { return directory; }
            set { directory = value; }
        }

        public long sizeInBytes_ForNUnit
        {
            get { return sizeInBytes; }
        }
	}
}