Ckan: Add downloads to cache immediately upon individual completion

[jupiterbjy]

Background

CKAN Version:
v1.26.0

KSP Version:
1.7

Operating System:
Win10 x64

Have you made any manual changes to your GameData folder (i.e., not via CKAN)?
Nothing other than installing NearFuture Aeronautics, not related with issue.

Description

This is not an urgent request, rather - a minor, maybe even personal one.

When downloading mods, CKAN wait for all mods to be downloaded in temporary folder before copying to 'Download Cache' folder, and does not remove those .tmp files until clean exit of CKAN.

But when downloading multiple large mods, they would easily fill up Ramdisk causing CKAN to hang on download indefinitely. In that case: .tmp files will stay and take up space until reboot.

If CKAN moves a mod to 'Download Cache' folder as soon as it's complete and remove corresponding .tmp file, user can cancel download and not loose progress of already completed downloads, or need to care about their Temporary folder capacity.

[DasSkelett]

This would need some changes in the after-download logic.
Right now, the temp files are deleted ModuleDonwloadsComplete(), after all downloads have finished and have been copied to the cache:
https://github.com/KSP-CKAN/CKAN/blob/2119b5802494a8e1fa7f9250dfe834a27da64fdf/Core/Net/NetAsyncModulesDownloader.cs#L79-L117

If we want to delete tempfiles after each download, we basically need to move the whole ModuleDownloadsComplete() function to FileDownloadComplete(), or call the (modified) first one in the second one, and do it for one mod at a time (which isn't too different to how we handle it now, with a for-loop).
But I don't yet see a way to do this without mixing NetAsyncDownloader and NetAsyncModulesDownloader.

[HebaruSan]

I just want to make a note regarding this:

But when downloading multiple large mods, they would easily fill up Ramdisk

If downloading multiple large mods can fill your temp folder, you're at risk of one large mod filling your temp folder, and you need a bigger temp folder.

[jupiterbjy]

Yup, but I still didn't see any mod that's over 4GB yet. And it's quite rare to see that Temp folder filled up unless some big mods decide to release update at same time. Therefore, I was referring this as 'not urgent' request, which might still cause issue to some players.