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 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
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 * *   Redistributions of source code must retain the above 
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 *     following disclaimer. 
 * *   Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
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 */

using System;
using System.IO;
using System.Reflection;
using System.Text;
using ICSharpCode.SharpZipLib.Tar;

namespace XenCenterLib.Archive
{
    public class TarArchiveWriter : ArchiveWriter
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private TarOutputStream tar = null;
        private const long bufferSize = 32 * 1024;
        private bool disposed;

        /// <summary>
        /// Parameterless constructor needed by tests
        /// </summary>
        public TarArchiveWriter()
        {
        }

        public TarArchiveWriter(Stream outputStream)
        {
            tar = new TarOutputStream(outputStream);
            disposed = false;
        }

        public override void SetBaseStream(Stream outputStream)
        {
            tar = new TarOutputStream(outputStream);
            disposed = false;
        }

        public override void AddDirectory(string directoryName, DateTime modificationTime)
        {
            StringBuilder sb = new StringBuilder(directoryName);

            //Need to add a terminal front-slash to add a directory
            if (!directoryName.EndsWith("/"))
                sb.Append("/");
            TarEntry entry = TarEntry.CreateTarEntry(sb.ToString());
            entry.ModTime = modificationTime;

            tar.PutNextEntry(entry);
            tar.CloseEntry();
        }

        public override void Add(Stream filetoAdd, string fileName, DateTime modificationTime, Action cancellingDelegate)
        {
            TarEntry entry = TarEntry.CreateTarEntry(fileName);
            entry.Size = filetoAdd.Length;
            entry.ModTime = modificationTime;

            tar.PutNextEntry(entry);
            byte[] buffer = new byte[bufferSize];
            int n;

            //You have to do this because if using a memory stream the pointer will be at the end it
            //it's just been read and this will cause nothing to be written out
            filetoAdd.Position = 0;

            while ((n = filetoAdd.Read(buffer, 0, buffer.Length)) > 0)
            {
                cancellingDelegate?.Invoke();
                tar.Write(buffer, 0, n);
            }

            tar.Flush();
            tar.CloseEntry();
        }

        protected override void Dispose(bool disposing)
        {
            if (!disposed && disposing)
            {
                try
                {
                    tar?.Dispose();
                }
                catch (Exception e)
                {
                    //workaround for CA-347483
                    log.Error("Failed to dispose tar output stream", e);
                }

                disposed = true;
            }

            base.Dispose(disposing);
        }
    }
}