Add Mission Control Animation Disabling

[Melonchanism]

While doing some debugging on trying to find out how to switch spaces in Mission Control programmatically without injecting keystrokes, I found that it is possible to disable / adjust the animation duration for entering / exiting / clicking on a space in Mission Control. This doesn't affect switching spaces without closing Mission Control via keyboard shortcuts, or show desktop, but weirdly affects hide desktop.

Code for a working dylib PoC:

#import <objc/objc-runtime.h>
#import <AppKit/AppKit.h>

double hook_animationDuration(void) {
    return 0.0;
}

__attribute__((constructor))
static void init(void) {
    Class WVExpose = NSClassFromString(@"WVExpose");
    Class _TtC8DockCore8WVExpose = NSClassFromString(@"_TtC8DockCore8WVExpose");
    SEL orig_selector = @selector(animationDuration);
    Method orig_method = class_getInstanceMethod(WVExpose, orig_selector);
    Method orig_method_alt = class_getInstanceMethod(_TtC8DockCore8WVExpose, orig_selector);
    method_setImplementation(orig_method, (IMP)hook_animationDuration);
    method_setImplementation(orig_method_alt, (IMP)hook_animationDuration);
}

Modifications could be made to adjust the timing (original is 0.25).
Note the added mangled version for compatibility (unmangled on 15, mangled on 26, and other variations).
Don't know if method swizzling is something that can / will be part of yabai but here we are.

out.mov

[asmvik]

The current instruction-patching in the scripting-addition to remove the space switching animation (0.25sec by default) when using cmd+tab and/or focusing a window in a different space, is implemented that way (patching a specific read instruction instead of patching the value at the location that was read) because the source value is read from multiple places, including when showing elements in Mission Control/Expose. Patching the source made some of these other interactions less.. nice to use.

There is nothing stopping you from doing method swizzling from inside the scripting-addition.

[Melonchanism]

From my observation, [WVExpose animationDuration] contains its own value when it decides to have something called "slowmotion" enabled/disabled. It references to a subroutine that I couldn't find mentioned anywhere else, and sets register D0 to 0.25.

Anyways I'll see if I can find out how the config on yabai works because mission control still feels at lot faster at even 0.1 while still feeling fluid.

[Melonchanism]

It took several modifications to different parts of the project because of the nature of storing a value both in the SA and in yabai config, but I managed to get a configurable working version as part of the SA and have already made docs.
https://github.com/Melonchanism/yabai

[Melonchanism]

@asmvik Could you take a look at my fork and see if anything should be changed back to the original (eg client_send_message not being static so it could be called from sa.c)