Things such as Output, InputDevice and so on are made to be
multi-purpose. In order to make this separation more clear, this change
moves that code in the core directory. Some things still link to the
abstraction level above (kwin), they can be tackled in future refactors.
Ideally code in core/ should depend either on other code in core/ or
system libs.
At the moment, a platform should provide two output lists - one that
lists all available outputs, and the other one that contains only
enabled outputs. In general, this amounts to some boilerplate code and
forces backends to be implemented in some certain way, which sometimes
is inconvenient, e.g. if an output is disabled or enabled, it will be
simpler if we only change Output::isEnabled(), otherwise we need to
start accounting for corner cases such as the order in which
Output::isEnabled() and Platform::enabledOutputs() are changed, etc.
The Session can be useful not only to the platform backend but also
input backends and for things such as vt switching, etc. Therefore it's
better to have the Application own the Session.
There are a few benefits to using smart pointers from the standard library:
- std::unique_ptr has move semantics. With move semantics, transfer of ownership
can be properly expressed
- std::shared_ptr is more efficient than QSharedPointer
- more developers are used to them, making contributions for newcomers easier
We're also already using a mix of both; because Qt shared pointers provide
no benefits, porting to standard smart pointers improves consistency in
the code base. Because of that, this commit ports most of the uses of QSharedPointer
to std::shared_ptr, and some uses of QScopedPointer to std::unique_ptr
