EPPlus/Packaging/ZipPackagePart.cs

/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * Copyright (C) 2011  Jan Källman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 * See the GNU Lesser General Public License for more details.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied. 
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 * 
 * Author							Change						Date
 *******************************************************************************
 * Jan Källman		Added		25-Oct-2012
 *******************************************************************************/
using System;
using System.IO;
using System.IO.Compression;

namespace OfficeOpenXml.Packaging
{
    internal class ZipPackagePart : ZipPackageRelationshipBase, IDisposable
    {
        internal delegate void SaveHandlerDelegate(StreamWriter streamWriter);

        internal ZipPackagePart(ZipPackage package, ZipArchiveEntry entry)
        {
            Package = package;
            SaveHandler = null;
            Uri = new Uri(package.GetUriKey(entry.FullName), UriKind.Relative);
        }
        internal ZipPackagePart(ZipPackage package, Uri partUri, string contentType, CompressionLevel compressionLevel)
        {
            Package = package;
            //Entry = new ZipEntry();
            //Entry.FileName = partUri.OriginalString.Replace('/','\\');
            Uri = partUri;
            ContentType = contentType;
            CompressionLevel = compressionLevel;
        }
        internal ZipPackage Package { get; set; }
        internal CompressionLevel CompressionLevel;
        MemoryStream _stream = null;
        internal MemoryStream Stream
        {
            get
            {
                return _stream;
            }
            set
            {
                _stream = value;
            }
        }
        internal override ZipPackageRelationship CreateRelationship(Uri targetUri, TargetMode targetMode, string relationshipType)
        {

            var rel = base.CreateRelationship(targetUri, targetMode, relationshipType);
            rel.SourceUri = Uri;
            return rel;
        }
        internal MemoryStream GetStream()
        {
            return GetStream(FileMode.OpenOrCreate, FileAccess.ReadWrite);
        }
        internal MemoryStream GetStream(FileMode fileMode)
        {
            return GetStream(FileMode.Create, FileAccess.ReadWrite);
        }
        internal MemoryStream GetStream(FileMode fileMode, FileAccess fileAccess)
        {
            if (_stream == null || fileMode == FileMode.CreateNew || fileMode == FileMode.Create)
            {
                _stream = new MemoryStream();
            }
            else
            {
                _stream.Seek(0, SeekOrigin.Begin);                
            }
            return _stream;
        }

        string _contentType = "";
        public string ContentType
        {
            get
            {
                return _contentType;
            }
            internal set
            {
                if (!string.IsNullOrEmpty(_contentType))
                {
                    if (Package._contentTypes.ContainsKey(Package.GetUriKey(Uri.OriginalString)))
                    {
                        Package._contentTypes.Remove(Package.GetUriKey(Uri.OriginalString));
                        Package._contentTypes.Add(Package.GetUriKey(Uri.OriginalString), new ZipPackage.ContentType(value, false, Uri.OriginalString));
                    }
                }
                _contentType = value;
            }
        }
        public Uri Uri { get; private set; }
        internal SaveHandlerDelegate SaveHandler
        {
            get;
            set;
        }
        internal void WriteZip(ZipArchive zipArchive)
        {
            byte[] b;
            if (SaveHandler == null)
            {
                b = GetStream().ToArray();
                if (b.Length == 0)   //Make sure the file isn't empty. DotNetZip streams does not seems to handle zero sized files.
                {
                    return;
                }
                var zipEntry = zipArchive.CreateEntry(Uri.OriginalString);
                using var os = zipEntry.Open();
                os.Write(b);
            }
            else
            {
                var zipEntry = zipArchive.CreateEntry(Uri.OriginalString);
                using var streamWriter = new StreamWriter(zipEntry.Open());
                SaveHandler(streamWriter);
            }

            if (_rels.Count > 0)
            {
                string f = Uri.OriginalString;
                var name = Path.GetFileName(f);
                _rels.WriteZip(zipArchive, $"{f.Substring(0, f.Length - name.Length)}_rels/{name}.rels");
            }
            b = null;
        }


        public void Dispose()
        {
            _stream.Close();
            _stream.Dispose();
        }
    }
}