Fixed directory deletion for SMB and FTP storages

[PVince81]

Added deleteFileOrDir() operation

Some storages need to use different calls for deleting files or folders, usually unlink() and rmdir().

For this, added a new operation deleteFileOrDir() which default implementation will first detect whether the given argument is a file or a directory to decide which operation to use.

Some storage implementations don't need to distinguish them, in which case they reimplement deleteFileOrDir() to save the extra is_dir() detection.

Fixes #4532 (SMB dir deletion)
Fixes #5941 (FTP dir deletion)

This is based on @icewind1991's suggestion here: #4531 (comment)
I tried to not break the existing APIs.
Currently, only the ajax delete.php is using that new call.

If not acceptable, the alternative is to do the is_dir() detection in delete.php for now...

Please review @icewind1991 @karlitschek @DeepDiver1975 @schiesbn

[PVince81]

Note: I ran the unit tests for FTP, SFTP, SMB, WebDAV and Dropbox and it seemed to work fine.

[karlitschek]

yes. 👍

[icewind1991]

I would prefer to call the function delete instead of deleteFileOrDir, otherwise 👍

[PVince81]

I decided against delete() because one might think it is a PHP function (there is even a docs page for it that refers to unlink). deleteFileOrDir() makes it clearer to distinguish from unlink and rmdir than delete.
i do agree that it looks a bit ugly 😉

[PVince81]

Looks like I forgot some wrappers...

[PVince81]

Fetch Jenkins, fetch!

@owncloud-bot please retest this

[PVince81]

Failed to fetch again it seems 😦

@owncloud-bot retest please

[ghost]

Test passed.
Refer to this link for build results: https://ci.owncloud.org/job/pull-request-analyser/2203/

[MorrisJobke]

Is this ready to merge?

[PVince81]

It should be.
I'm still a bit afraid that the addition to the interface break other things like third party apps that might implement their own storages (probably unlikely).
But since we're increasing the major version, that should be ok ?
What do you think @karlitschek ?

[PVince81]

👎 had a chat with @schiesbn and we decided to use a less risky approach: put the code for "detect if dir, then use rmdir" inside the specific ext storage classes directly. This way we don't add new API calls and make this backportable to stable5.

[PVince81]

Superseded by #6123

[PVince81]

Backported to stable5 as 3b18c1b