RAMFile.cs

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/* 
 * 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
{
    
    [Serializable]
    public class RAMFile
    {
        
        private const long serialVersionUID = 1L;
        
        protected System.Collections.Generic.List<byte[]> buffers = new System.Collections.Generic.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.UtcNow.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

        internal virtual long Length
        {
            get
            {
                lock (this)
                {
                    return length;
                }
            }
            set
            {
                lock (this)
                {
                    this.length = value;
                }
            }
        }

        // For non-stream access from thread that might be concurrent with writing

        internal virtual long LastModified
        {
            get
            {
                lock (this)
                {
                    return lastModified;
                }
            }
            set
            {
                lock (this)
                {
                    this.lastModified = value;
                }
            }
        }

        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.internalSizeInBytes += size;
                }
            }

            return buffer;
        }
        
        public /*internal*/ byte[] GetBuffer(int index)
        {
            lock (this)
            {
                return 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 virtual long SizeInBytes
        {
            get
            {
                lock (this)
                {
                    return sizeInBytes;
                }
            }
        }
    }
}