osu/osu.Game/Database/LegacyExporter.cs

133 lines
6.2 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.
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using osu.Framework.Platform;
using osu.Game.Extensions;
using osu.Game.Overlays.Notifications;
using osu.Game.Utils;
using Realms;
namespace osu.Game.Database
{
/// <summary>
/// Handles exporting models to files for sharing / consumption outside the game.
/// </summary>
public abstract class LegacyExporter<TModel>
where TModel : RealmObject, IHasNamedFiles, IHasGuidPrimaryKey
{
/// <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;
public Action<Notification>? PostNotification { get; set; }
protected LegacyExporter(Storage storage)
{
exportStorage = storage.GetStorageForDirectory(@"exports");
UserFileStorage = storage.GetStorageForDirectory(@"files");
}
/// <summary>
/// Returns the baseline name of the file to which the <paramref name="item"/> will be exported.
/// </summary>
/// <remarks>
/// The name of the file will be run through <see cref="ModelExtensions.GetValidFilename"/> to eliminate characters
/// which are not permitted by various filesystems.
/// </remarks>
/// <param name="item">The item being exported.</param>
protected virtual string GetFilename(TModel item) => item.GetDisplayString();
/// <summary>
/// Exports a model to the default export location.
/// This will create a notification tracking the progress of the export, visible to the user.
/// </summary>
/// <param name="model">The model to export.</param>
/// <param name="cancellationToken">A cancellation token.</param>
public async Task ExportAsync(Live<TModel> model, CancellationToken cancellationToken = default)
{
string itemFilename = model.PerformRead(s => GetFilename(s).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}");
ProgressNotification notification = new ProgressNotification
{
State = ProgressNotificationState.Active,
Text = $"Exporting {itemFilename}...",
};
PostNotification?.Invoke(notification);
using var linkedSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, notification.CancellationToken);
try
{
using (var stream = exportStorage.CreateFileSafely(filename))
{
await ExportToStreamAsync(model, stream, notification, linkedSource.Token).ConfigureAwait(false);
}
}
catch
{
notification.State = ProgressNotificationState.Cancelled;
// cleanup if export is failed or canceled.
exportStorage.Delete(filename);
throw;
}
notification.CompletionText = $"Exported {itemFilename}! Click to view.";
notification.CompletionClickAction = () => exportStorage.PresentFileExternally(filename);
notification.State = ProgressNotificationState.Completed;
}
/// <summary>
/// Exports a model to a provided stream.
/// </summary>
/// <param name="model">The model to export.</param>
/// <param name="outputStream">The output stream to export to.</param>
/// <param name="notification">An optional notification to be updated with export progress.</param>
/// <param name="cancellationToken">A cancellation token.</param>
public Task ExportToStreamAsync(Live<TModel> model, Stream outputStream, ProgressNotification? notification = null, CancellationToken cancellationToken = default) =>
Task.Run(() => { model.PerformRead(s => ExportToStream(s, outputStream, notification, cancellationToken)); }, cancellationToken);
/// <summary>
/// Exports a model to a provided stream.
/// </summary>
/// <param name="model">The model to export.</param>
/// <param name="outputStream">The output stream to export to.</param>
/// <param name="notification">An optional notification to be updated with export progress.</param>
/// <param name="cancellationToken">A cancellation token.</param>
public abstract void ExportToStream(TModel model, Stream outputStream, ProgressNotification? notification, CancellationToken cancellationToken = default);
}
}