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使下载管理器可用 #122

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使下载管理器可用 #122

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231 changes: 202 additions & 29 deletions PixivFSUWP/Data/DownloadManager.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using Lumia.Imaging.Compositing;

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
Expand All @@ -8,30 +9,73 @@
using System.Text;
using System.Threading;
using System.Threading.Tasks;

using Windows.Storage;
using Windows.UI.Core;

namespace PixivFSUWP.Data
{
//下载完成时的事件参数
public class DownloadCompletedEventArgs : EventArgs
{
public DownloadCompletedEventArgs()
{
}

public DownloadCompletedEventArgs(bool hasError) => HasError = hasError;

public bool HasError { get; set; }
}

public class DownloadJobStatusChangedEventArgs : EventArgs
{
public DownloadJobStatusChangedEventArgs(DownloadJobStatus status) => Status = status;
public DownloadJobStatus Status { get; }
}
public enum DownloadJobStatus
{
Readying,
Running,
Pausing,
Canceled,
Finished,
Faild,
}
public class DownloadJob : INotifyPropertyChanged
{
public string Title { get; }
public string Uri { get; }
public string FilePath { get; }

public bool IsPause
{
get => isPause; set
{
isPause = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsPause)));
}
}
public DownloadJobStatus Status
{
get => status; protected set
{
if (status == value)
return;
status = value;
StatusChanged?.Invoke(this, new DownloadJobStatusChangedEventArgs(status));
}
}
private int progress;
private DownloadJobStatus status = DownloadJobStatus.Readying;
private bool isPause = false;

public int Progress
{
get => progress;
private set
{
progress = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Progress"));
_ = Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(
CoreDispatcherPriority.High,
() => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Progress))));
}
}

Expand All @@ -48,14 +92,16 @@ public DownloadJob(string Title, string Uri, string FilePath)
public bool Downloading { get; private set; }

//用于暂停的ManualResetEvent
ManualResetEvent pauseEvent = new ManualResetEvent(true);
readonly ManualResetEvent pauseEvent = new ManualResetEvent(true);

//用于取消任务的CancellationTokenSource
CancellationTokenSource tokenSource = new CancellationTokenSource();
readonly CancellationTokenSource tokenSource = new CancellationTokenSource();

//下载完成时的事件
public event Action<DownloadJob, DownloadCompletedEventArgs> DownloadCompleted;

public event Action<DownloadJob, DownloadJobStatusChangedEventArgs> StatusChanged;

//通知属性更改
public event PropertyChangedEventHandler PropertyChanged;

Expand All @@ -66,65 +112,92 @@ public async Task Download()
{
Downloading = true;
using (var memStream = await OverAll.DownloadImage(Uri, tokenSource.Token, pauseEvent, async (loaded, length) =>
{
await Task.Run(() =>
{
Progress = (int)(loaded * 100 / length);
});
}))
await Task.Run(() =>
{
Status = DownloadJobStatus.Running;
Progress = (int)(loaded * 100 / length);
});
}))
{
if (tokenSource.IsCancellationRequested) return;
var file = await StorageFile.GetFileFromPathAsync(FilePath);
CachedFileManager.DeferUpdates(file);
using (var fileStream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
await memStream.CopyToAsync(fileStream.AsStream());
}
var result = await CachedFileManager.CompleteUpdatesAsync(file);
if (result == Windows.Storage.Provider.FileUpdateStatus.Complete)
{
DownloadCompleted?.Invoke(this, new DownloadCompletedEventArgs() { HasError = false });
}
else
{
DownloadCompleted?.Invoke(this, new DownloadCompletedEventArgs() { HasError = true });
}
if (tokenSource.IsCancellationRequested)
return;

var result = await WriteToFile(memStream);
Status = DownloadJobStatus.Finished;
_ = Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(
CoreDispatcherPriority.High,
() => DownloadCompleted?.Invoke(this, new DownloadCompletedEventArgs(result != Windows.Storage.Provider.FileUpdateStatus.Complete)));

}
Downloading = false;
}
}
// 文件的写入方法
protected virtual async Task<Windows.Storage.Provider.FileUpdateStatus> WriteToFile(Stream memStream)
{
var file = await StorageFile.GetFileFromPathAsync(FilePath);
CachedFileManager.DeferUpdates(file);
using (var fileStream = await file.OpenAsync(FileAccessMode.ReadWrite))
await memStream.CopyToAsync(fileStream.AsStream());
return await CachedFileManager.CompleteUpdatesAsync(file);
}

//暂停下载
public void Pause()
{
IsPause = true;
pauseEvent.Reset();
Status = DownloadJobStatus.Pausing;
}

//恢复下载
public void Resume()
{
IsPause = false;
pauseEvent.Set();
Status = DownloadJobStatus.Readying;
}

//取消下载
public void Cancel()
{
tokenSource.Cancel();
Status = DownloadJobStatus.Canceled;
}
}
public class DownloadJobPlus : DownloadJob
{
protected readonly StorageFile File;

public DownloadJobPlus(string Title, string Uri, StorageFile File) : base(Title, Uri, File.Path) => this.File = File;

protected override async Task<Windows.Storage.Provider.FileUpdateStatus> WriteToFile(Stream memStream)
{
CachedFileManager.DeferUpdates(File);
using (var fileStream = await File.OpenAsync(FileAccessMode.ReadWrite))
await memStream.CopyToAsync(fileStream.AsStream());
return await CachedFileManager.CompleteUpdatesAsync(File);
}
}
//静态的下载管理器。应用程序不会有多个下载管理器实例。
public static class DownloadManager
{
//下载任务列表
public static ObservableCollection<DownloadJob> DownloadJobs = new ObservableCollection<DownloadJob>();
public static ObservableCollection<DownloadJob> FinishedJobs = new ObservableCollection<DownloadJob>();

//添加下载任务
public static void NewJob(string Title, string Uri, string FilePath)
=> JobBackgroundWork(new DownloadJob(Title, Uri, FilePath));
public static void NewJob(string Title, string Uri, StorageFile File)
=> JobBackgroundWork(new DownloadJobPlus(Title, Uri, File));

private static void JobBackgroundWork(DownloadJob job)
{
var job = new DownloadJob(Title, Uri, FilePath);
job.DownloadCompleted += Job_DownloadCompleted;
DownloadJobs.Add(job);
_ = job.Download();
DownloadProcessManager.Enqueue(job);
}

//有任务下载完成时的事件
Expand All @@ -133,8 +206,11 @@ public static void NewJob(string Title, string Uri, string FilePath)
//下载完成时
private static void Job_DownloadCompleted(DownloadJob source, DownloadCompletedEventArgs args)
{
DownloadJobs.Remove(source);
System.Diagnostics.Debug.WriteLine("[Job_DownloadCompleted]: " + source.Title);
source.DownloadCompleted -= Job_DownloadCompleted;
DownloadCompleted?.Invoke(source.Title, args.HasError);
FinishedJobs.Add(source);
DownloadJobs.Remove(source);
}

//移除下载任务
Expand All @@ -153,5 +229,102 @@ public static void RemoveJob(DownloadJob Job)
Job.Cancel();
DownloadJobs.Remove(Job);
}

private static class DownloadProcessManager
{
private static readonly Mutex download_lock = new Mutex();// 同步锁
private static readonly List<DownloadJob> downloadingJobs = new List<DownloadJob>();// 正在下载任务列表
private static readonly Queue<DownloadJob> downloadJobs = new Queue<DownloadJob>();// 下载队列
private static readonly List<DownloadJob> waitingJobs = new List<DownloadJob>();// 暂停任务列表
private static Thread DownloadProcessThread = null;

/// <summary>
/// 同时下载最大进程数
/// </summary>
public static int MaxJobs { get; set; } = 3;

static DownloadProcessManager() => new Thread(DownloadProcessDaemon).Start();

public static void Enqueue(DownloadJob job)
{
job.StatusChanged += Job_StatusChanged;
downloadJobs.Enqueue(job);
}

private static void DownloadProcess()
{
System.Diagnostics.Debug.WriteLine("[DownloadProcess]: 启动");
if (!download_lock.WaitOne(200))
{
System.Diagnostics.Debug.WriteLine("[DownloadProcess]: 程序正在运行");
return;
}
try
{
System.Diagnostics.Debug.WriteLine("[DownloadProcess]: 运行中");
while (true)
{
lock (downloadingJobs)
{
if (downloadingJobs.Count < MaxJobs)
{
if (downloadJobs.Count > 0)
{
var job = downloadJobs.Dequeue();
downloadingJobs.Add(job);
System.Diagnostics.Debug.WriteLine("[DownloadProcess]: 开始下载: " + job.Title);
_ = job.Download();
}
}
}
}
}
finally
{
System.Diagnostics.Debug.WriteLine("[DownloadProcess]: 意外结束");
download_lock.ReleaseMutex();
}
}

private static void Job_StatusChanged(DownloadJob job, DownloadJobStatusChangedEventArgs e)
{
System.Diagnostics.Debug.WriteLine($"[Job_StatusChanged]: {job.Title} = {e.Status}");
switch (e.Status)
{
case DownloadJobStatus.Readying:
waitingJobs.Remove(job);
downloadJobs.Enqueue(job);
break;
case DownloadJobStatus.Running:
break;
case DownloadJobStatus.Pausing:
lock (downloadingJobs)
downloadingJobs.Remove(job);
waitingJobs.Add(job);
break;
case DownloadJobStatus.Canceled:
case DownloadJobStatus.Finished:
job.StatusChanged -= Job_StatusChanged;
lock (downloadingJobs)
downloadingJobs.Remove(job);
break;
default:
break;
}
}

private static void DownloadProcessDaemon()
{
System.Diagnostics.Debug.WriteLine("[DownloadProcessDaemon]: 启动");
DownloadProcessThread = new Thread(DownloadProcess);
while (true)
{
if (!DownloadProcessThread.IsAlive)
(DownloadProcessThread = new Thread(DownloadProcess)).Start();
else
Thread.Sleep(2000);
}
}
}
}
}
9 changes: 7 additions & 2 deletions PixivFSUWP/DownloadManager.xaml
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Original file line number Diff line number Diff line change
Expand Up @@ -10,8 +10,8 @@
<SolidColorBrush x:Key="NavigationViewExpandedPaneBackground" Color="Transparent"/>
<SolidColorBrush x:Key="NavigationViewDefaultPaneBackground" Color="Transparent"/>
</Page.Resources>
<Grid Margin="0 75 0 0">
<NavigationView PaneDisplayMode="Left" IsBackButtonVisible="Collapsed"
<Grid MinWidth="300" MinHeight="200">
<NavigationView PaneDisplayMode="Top" IsBackButtonVisible="Collapsed"
IsSettingsVisible="False" IsPaneToggleButtonVisible="False"
x:Name="NavControl" SelectionChanged="NavControl_SelectionChanged">
<NavigationView.MenuItems>
Expand All @@ -23,5 +23,10 @@
<Frame x:Name="ContentFrame"/>
</ScrollViewer>
</NavigationView>
<Grid.ChildrenTransitions>
<TransitionCollection>
<AddDeleteThemeTransition/>
</TransitionCollection>
</Grid.ChildrenTransitions>
</Grid>
</Page>
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