Bugfix for issue 10862: Trash-bin ignores trashbin_retention_obligation

[felixn]

Fix for #10862

The method used by Trashbin.php to calculate used space included external storage, while the quota doesn't include external storage. This led to $free space always being way too small (or negative), leading trashbin to purge all deleted files.

The calculation for used space, free space and quota was replaced by the version used by the Versions app:

server/apps/files_versions/lib/Storage.php

Lines 756 to 758 in 4adac44

	$files_view = new View('/' . $uid . '/files');
	$rootInfo = $files_view->getFileInfo('/', false);
	$free = $quota - $rootInfo['size']; // remaining free space for user

@GAS85
@MorrisJobke
@danielkesselberg

[rullzer]

I'm not a big fan of reverting back to the view. The node API is cleaner IMO. But if there is no other way.

@icewind1991 I leave this to your expertise.

[rullzer]

And thanks a lot for your pr @felixn! welcome!

[icewind1991]

I think this is fine to backport to stable15, then for 16 we can extend the node api to provide this info

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22
Most developers hang out on IRC. So join #nextcloud-dev on Freenode for a chat!

[MorrisJobke]

/backport to stable15

[MorrisJobke]

/backport to stable14

[backportbot-nextcloud]

backport to stable14 in #14415

[backportbot-nextcloud]

backport to stable15 in #14414

[icewind1991]

node api extension: #14412

[MorrisJobke]

Revert of this with the usage of the new API from #14412 can be found at #14454