In OnMenuRecentFile() we don't need to construct a QFileInfo instance
just to check if a file exists, we can just use the static member
function to do that (which Qt's documentation also notes as quicker than
constructing an instance).
In UpdateUITheme(), we just want to try and open the file and check the
success of that operation. Technically speaking, between the existence
check and the open call, the file can be deleted or moved, but still
appear to succeed in code. i.e.
1. Existence check -> Returns true
2. File is moved/deleted
3. Open is called, the return value of which isn't checked
4. Nonsense behavior
This way we combine the existence check and the open into one.
We move the initialization of the renderer to the core class, while
keeping the creation of it and any other specifics in video_core. This
way we can ensure that the renderer is initialized and doesn't give
unfettered access to the renderer. This also makes dependencies on types
more explicit.
For example, the GPU class doesn't need to depend on the
existence of a renderer, it only needs to care about whether or not it
has a rasterizer, but since it was accessing the global variable, it was
also making the renderer a part of its dependency chain. By adjusting
the interface, we can get rid of this dependency.
General moving to keep kernel object types separate from the direct
kernel code. Also essentially a preliminary cleanup before eliminating
global kernel state in the kernel code.
Makes the global a member of the RendererBase class. We also change this
to be a reference. Passing any form of null pointer to these functions
is incorrect entirely, especially given the code itself assumes that the
pointer would always be in a valid state.
This also makes it easier to follow the lifecycle of instances being
used, as we explicitly interact the renderer with the rasterizer, rather
than it just operating on a global pointer.
Instead of using an unsigned int as a parameter and expecting a user to
always pass in the correct values, we can just convert the enum into an
enum class and use that type as the parameter type instead, which makes
the interface more type safe.
We also get rid of the bookkeeping "NUM_" element in the enum by just
using an unordered map. This function is generally low-frequency in
terms of calls (and I'd hope so, considering otherwise would mean we're
slamming the disk with IO all the time) so I'd consider this acceptable
in this case.
This doesn't actually modify the internal class state, so it can be a
const member function. While we're at it, amend the function to take
its arguments by const reference.
QString initializes to an empty string by default, so this does nothing
meaningful. While we're at it, use a constructor initializer list for
initializing the gamelist member variable.
