SPIFFSFS class should not shadow methods in FS class

[judge2005]

Please see espressif/esp-idf#3427 for code samples, platform details and discussion. To summarize:

The FS class is not designed to be subclassed insofar as none of its methods are virtual. Re-implementing those methods in SPIFFSFS does not override them, it hides them, so instances of SPIFFSFS can not be passed as references or pointers to the FS class. If they are, the FS methods will be called instead and will not work reliably for a SPIFFS filing system (the existing unit tests are all positive - they test that things work when the files are as they are supposed to be, they don't test negative situations such as files not actually existing).

Instead, an instance of a SPIFFSFS class (such as the instance called SPIFFS) should inject a SPIFFS-specific implementation class into the superclass.

[judge2005]

Created pull request: #2763

[judge2005]

This also fixes #1264 On May 13, 2019, at 5:16 PM, Me No Dev <[email protected]> wrote: Closed #2750 <#2750> via fd5a2f0 <fd5a2f0> . — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2750?email_source=notifications&email_token=AACH444LO54BGPBWKSGG5BTPVHLBFA5CNFSM4HK7G5K2YY3PNVWWK3TUL52HS4DFWZEXG43VMVCXMZLOORHG65DJMZUWGYLUNFXW5KTDN5WW2ZLOORPWSZGORNPQXXI#event-2338261981>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AACH444LG3E2FLXAFF27PQLPVHLBFANCNFSM4HK7G5KQ> .