Make sure we don't scan files that can not be accessed

[nickvergessen]

Steps

1. create a folder on the file system:

mkdir "data/admin/files/te
st"

2. Run files:scan admin
3. Try to delete the folder after realizing your problem

With this fix the file is not added on scanning.

@icewind1991 @MorrisJobke @LukasReschke

Fix #1965

[mention-bot]

@nickvergessen, thanks for your PR! By analyzing the history of the files in this pull request, we identified @icewind1991, @DeepDiver1975 and @butonic to be potential reviewers.

[MorrisJobke]

1) OCA\Files_Sharing\Tests\External\ScannerTest::testScan
Your test case is not allowed to access the database.
2) OCA\Files_Sharing\Tests\External\ScannerTest::testScanFile
Your test case is not allowed to access the database.

[nickvergessen]

I will fix that, once @icewind1991 confirmed this is the way to go.

[icewind1991]

Can't we reuse the fragment from somewhere else (View?) and just call that

[nickvergessen]

That was exactly what I wondered aswell, but I think the cache is inside the view, so this looks shitty from dependency pov. But should we just move it to a separate helper or something?

[nickvergessen]

@icewind1991 should we simply move all the checks from the View into IStorage::verifyPath and in the view then simply resolve the path to the storage and call the method?

[nickvergessen]

@icewind1991 moved the validation from view to storage so it's in one place only

[MorrisJobke]

Tested and works 👍

@rullzer @icewind1991 Please review :)

[rullzer]

Fine by me 👍 But lets have our fs guru have the last vote. Summoning @icewind1991

[icewind1991]

👍

[MorrisJobke]

@nickvergessen Could you open the backport PR? Thanks