Created attachment 239054 [details] [review]
Refactor existing read code

The Android MTP stack implements a set of extensions that allow for direct I/O (read/write) on files - rather than only offering download/upload operations.

With these extensions, it's possible to implement the normal read/write methods in the backend API and allow normal applications to interact with files on the device.

This is implemented as a three part patch series:

1: Refactor existing read code for thumbnails to be useful for general reads too
2: Implement read methods
3: Implement write methods