Walks a few steps further along device inspection.

OSBindings/Mac/Clock Signal/Joystick Manager/CSJoystickManager.m

@@ -11,21 +11,29 @@
 @import IOKit;
 #include <IOKit/hid/IOHIDLib.h>
 
+@interface CSJoystickManager ()
+- (void)deviceMatched:(IOHIDDeviceRef)device result:(IOReturn)result sender:(void *)sender;
+- (void)deviceRemoved:(IOHIDDeviceRef)device result:(IOReturn)result sender:(void *)sender;
+@end
+
 static void DeviceMatched(void *context, IOReturn result, void *sender, IOHIDDeviceRef device) {
-	NSLog(@"Matched");
+	[(__bridge  CSJoystickManager *)context deviceMatched:device result:result sender:sender];
 }
 
 static void DeviceRemoved(void *context, IOReturn result, void *sender, IOHIDDeviceRef device) {
-	NSLog(@"Removed");
+	[(__bridge  CSJoystickManager *)context deviceRemoved:device result:result sender:sender];
 }
 
 @implementation CSJoystickManager {
 	IOHIDManagerRef _hidManager;
+	NSMutableSet<NSValue *> *_activeDevices;
 }
 
 - (instancetype)init {
 	self = [super init];
 	if(self) {
+		_activeDevices = [[NSMutableSet alloc] init];
+
 		_hidManager = IOHIDManagerCreate(kCFAllocatorDefault, kIOHIDOptionsTypeNone);
 		if(!_hidManager) return nil;
 
@@ -56,4 +64,57 @@ static void DeviceRemoved(void *context, IOReturn result, void *sender, IOHIDDev
 	CFRelease(_hidManager);
 }
 
+- (void)deviceMatched:(IOHIDDeviceRef)device result:(IOReturn)result sender:(void *)sender {
+	NSValue *const deviceKey = [NSValue valueWithPointer:device];
+	if([_activeDevices containsObject:deviceKey]) {
+		return;
+	}
+
+	[_activeDevices addObject:deviceKey];
+	NSLog(@"Matched");
+
+	const CFArrayRef elements = IOHIDDeviceCopyMatchingElements(device, NULL, kIOHIDOptionsTypeNone);
+	for(CFIndex index = 0; index < CFArrayGetCount(elements); ++index) {
+		const IOHIDElementRef element = (IOHIDElementRef)CFArrayGetValueAtIndex(elements, index);
+
+		// Check that this element is either on the generic desktop page or else is a button.
+		const uint32_t usagePage = IOHIDElementGetUsagePage(element);
+		if(usagePage != kHIDPage_GenericDesktop && usagePage != kHIDPage_Button) continue;
+
+		// Then inspect the usage and type.
+		const IOHIDElementType type = IOHIDElementGetType(element);
+
+		// IOHIDElementGetCookie
+
+		switch(type) {
+			default: break;
+			case kIOHIDElementTypeInput_Button:
+				// Add a buton
+			break;
+
+			case kIOHIDElementTypeInput_Misc:
+			case kIOHIDElementTypeInput_Axis: {
+				const uint32_t usage = IOHIDElementGetUsage(element);
+				// Add something depending on usage...
+			} break;
+
+			case kIOHIDElementTypeCollection:
+				// TODO: recurse.
+			break;
+		}
+	}
+
+	CFRelease(elements);
+}
+
+- (void)deviceRemoved:(IOHIDDeviceRef)device result:(IOReturn)result sender:(void *)sender {
+	NSValue *const deviceKey = [NSValue valueWithPointer:device];
+	if(![_activeDevices containsObject:deviceKey]) {
+		return;
+	}
+
+	[_activeDevices removeObject:deviceKey];
+	NSLog(@"Removed");
+}
+
 @end