Adds onFinished callback for SessionImpl::updateTrackersFromURL

[vafada]

Fixes #23508.

This PR adds onFinished param callback for SessionImpl::updateTrackersFromURL function.

The onFinished call back is called when setAdditionalTrackersFromURL is called or when the download of the tracker list failed.

This fixes the async issue when qBittorent is launched via CLI with the following conditions:

1. --skip-dialog=true
2. a torrent file or magnet url is specified to be downloaded
3. user has Automatically append trackers from URL to new downloads: set

In master, on app launch, an async task is started to download the url set in AdditionalTrackersURL. Meanwhile, the application would process the CLI params and immediately start the download of the torrent file or magnet url specified in the CLI param even before the download task finishes. This bug makes the Automatically append trackers from URL to new downloads: feature not work properly if the torrent download was triggered via CLI and if add torrent dialog is skipped.

With this PR, if the AdditionalTrackersURL is set, we wait for the download task to finish before starting up the session.

caveats

• if the url set in AdditionalTrackersURL is invalid, it would take 30 seconds for the app to startup since the default timeout for the http request is 30 seconds

qBittorrent/src/base/net/downloadmanager.cpp

Line 336 in 46cc3a3

request.setTransferTimeout();

• it would be nice to only do

updateTrackersFromURL([this]()
        {
            prepareStartup();
        });

if the CLI param has --skip-dialog=true and has a url param, but the sessionimpl class has no access to CLI params

[glassez]

I wouldn't call it a good idea to perform tasks sequentially that are ideal candidates for parallel execution. It seems that the issue requires a slightly more advanced solution. (Of course, if it's worth the effort. #23508 doesn't seem to have a large enough coverage so we could consider it as a known limitation rather than a bug.)

[glassez]

I have an idea. I’ll give it a try when the chance arises.

[Obegg]

Sorry to bother, is there any update on this?

[glassez]

Sorry to bother, is there any update on this?

I have an idea. I’ll give it a try when the chance arises.

There still wasn't time to do it.

[glassez]

BTW, wouldn't it be an acceptable compromise to just keep a list of downloaded trackers stored between sessions? Then it would always be available at startup, although it would probably be outdated, but it is unlikely that it is updated so often that this would be a problem.

[vafada]

@glassez do you suggest storing the list of tracker urls in qBittorrent.conf ? If yes, maybe a can take a stab at this

[glassez]

@glassez do you suggest storing the list of tracker urls in qBittorrent.conf ?

Well, certainly not in qBittorrent.conf. In a separate txt file in the qBittorrent data folder.

[vafada]

#23657