Disk Chooser List Issues

[ghedger]

The Disk Chooser, at present, runs in a constant spin loop where it rewinds the file/size lists and redraws the frame, as far as I can tell, at full speed. It is handled within an event handler called from Frame. This is very poor practice, to have a UI event loop within an event handler.

If a physical USB joystick is connected, about half the time selecting a file is extremely sluggish, sometimes requiring killing and restarting of the emulator. Cause has not been determined; only happens when a joystick is connected.

I propose we instead, building on the earlier DiskChoose refactor, further break up DiskChoose::ChooseAnImage() into

• Initialize: garner sorted list
• Message update

and, when F3/F4/other file choose is hit write to a a global state variable that dictates flow of the main outer message loop.

Loosely, the call cadence for the outer message loop is like this:
main() -> EnterMessageLoop() -> ContinueExecution()

This needs to live under EnterMessageLoop().

Furthermore, there's a homegrown templated data structure called List<>. List<> is defined in inc/list.h, contains comments in Spanish, and behaves like someone's class project. It was someone's valiant stab at a linked list. It has proven to be problematic, eliciting anomalous behavior, frequently double-printing some entries and omitting others, both of which are difficult to reproduce and seen typically in large directories. Now that we have access to C++11 features I suggest we explore replacing List<> with std::list<T, Allocator>.