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osu-lazer/osu.Game/Database/LegacyExporter.cs
2023-03-07 15:43:03 +03:00

94 lines
3.7 KiB
C#

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
#nullable disable
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using osu.Framework.Platform;
using osu.Game.Extensions;
using osu.Game.Utils;
using SharpCompress.Archives.Zip;
namespace osu.Game.Database
{
/// <summary>
/// A class which handles exporting legacy user data of a single type from osu-stable.
/// </summary>
public abstract class LegacyExporter<TModel>
where TModel : class, IHasNamedFiles
{
/// <summary>
/// Max length of filename (including extension).
/// </summary>
/// <remarks>
/// <para>
/// The filename limit for most OSs is 255. This actual usable length is smaller because <see cref="Storage.CreateFileSafely(string)"/> adds an additional "_<see cref="Guid"/>" to the end of the path.
/// </para>
/// <para>
/// For more information see <see href="https://www.ibm.com/docs/en/spectrum-protect/8.1.9?topic=parameters-file-specification-syntax">file specification syntax</see>, <seealso href="https://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits">file systems limitations</seealso>
/// </para>
/// </remarks>
public const int MAX_FILENAME_LENGTH = 255 - (32 + 4 + 2 + 5); //max path - (Guid + Guid "D" format chars + Storage.CreateFileSafely chars + account for ' (99)' suffix)
/// <summary>
/// The file extension for exports (including the leading '.').
/// </summary>
protected abstract string FileExtension { get; }
protected readonly Storage UserFileStorage;
private readonly Storage exportStorage;
protected LegacyExporter(Storage storage)
{
exportStorage = storage.GetStorageForDirectory(@"exports");
UserFileStorage = storage.GetStorageForDirectory(@"files");
}
protected virtual string GetFilename(TModel item) => item.GetDisplayString();
/// <summary>
/// Exports an item to a legacy (.zip based) package.
/// </summary>
/// <param name="item">The item to export.</param>
public void Export(TModel item)
{
string itemFilename = GetFilename(item).GetValidFilename();
if (itemFilename.Length > MAX_FILENAME_LENGTH - FileExtension.Length)
itemFilename = itemFilename.Remove(MAX_FILENAME_LENGTH - FileExtension.Length);
IEnumerable<string> existingExports =
exportStorage
.GetFiles(string.Empty, $"{itemFilename}*{FileExtension}")
.Concat(exportStorage.GetDirectories(string.Empty));
string filename = NamingUtils.GetNextBestFilename(existingExports, $"{itemFilename}{FileExtension}");
using (var stream = exportStorage.CreateFileSafely(filename))
ExportModelTo(item, stream);
exportStorage.PresentFileExternally(filename);
}
/// <summary>
/// Exports an item to the given output stream.
/// </summary>
/// <param name="model">The item to export.</param>
/// <param name="outputStream">The output stream to export to.</param>
public virtual void ExportModelTo(TModel model, Stream outputStream)
{
using (var archive = ZipArchive.Create())
{
foreach (var file in model.Files)
archive.AddEntry(file.Filename, UserFileStorage.GetStream(file.File.GetStoragePath()));
archive.SaveTo(outputStream);
}
}
}
}