public virtual Task ReadyFetchAsync(DownloadListenerContext context)
{
#if NETSTANDARD2_0
return(Task.CompletedTask);
#else
return(Task.FromResult(false));
#endif
}
private async Task DownloadPageAsync(ComicDownloadRequest request, ComicChapter chapter, ComicPage page, CancellationToken token)
{
var listener = request.Listener;
DownloadListenerContext listenerContext = null;
if (listener != null)
{
listenerContext = new DownloadListenerContext(request, chapter, page, token);
await listener.ReadyFetchAsync(listenerContext);
}
if (listener != null && token.IsCancellationRequested)
{
await listener.CanceledAsync(listenerContext);
return;
}
var ctx = new ComicDownloadContext(request.Entity, chapter, page, null, token);
if (!request.Saver.NeedToSave(ctx))
{
if (listener != null)
{
await listener.NotNeedToSaveAsync(listenerContext);
}
return;
}
try
{
if (listener != null)
{
await listener.BeginFetchPageAsync(listenerContext);
}
using (var stream = await request.Provider.GetImageStreamAsync(page.TargetUrl))
using (var destStream = streamManager.GetStream())
{
DownloadSaveListenerContext saveCtx = null;
if (listener != null)
{
saveCtx = new DownloadSaveListenerContext(request, chapter, page, token, destStream);
await listener.ReadySaveAsync(saveCtx);
}
await stream.CopyToAsync(destStream);
destStream.Seek(0, SeekOrigin.Begin);
ctx = new ComicDownloadContext(request.Entity, chapter, page, destStream, token);
await request.Saver.SaveAsync(ctx);
if (listener != null)
{
await listener.EndFetchPageAsync(saveCtx);
}
}
}
catch (Exception ex)
{
if (listener != null)
{
var errCtx = new DownloadExceptionListenerContext(request, chapter, page, token, ex);
await listener.FetchPageExceptionAsync(errCtx);
}
}
if (listener != null)
{
await listener.ComplatedSaveAsync(listenerContext);
}
}
public Task BeginFetchPageAsync(DownloadListenerContext context)
{
return(Task.WhenAll(this.Where(x => x != null).Select(x => x.BeginFetchPageAsync(context))));
}
public Task ReadyFetchAsync(DownloadListenerContext context)
{
return(Task.WhenAll(this.Where(x => x != null).Select(x => x.ReadyFetchAsync(context))));
}
public Task NotNeedToSaveAsync(DownloadListenerContext context)
{
return(Task.WhenAll(this.Where(x => x != null).Select(x => x.NotNeedToSaveAsync(context))));
}
public Task ComplatedSaveAsync(DownloadListenerContext context)
{
return(Task.WhenAll(this.Where(x => x != null).Select(x => x.ComplatedSaveAsync(context))));
}
