Function UpdateKeyState

Source/hook_include.cpp:651–705

void UpdateKeyState(KBDLLHOOKSTRUCT &event, vk_type vk, sc_type sc, bool key_up, bool aIsSuppressed)
// Always use the parameter vk rather than event.vkCode because the caller or caller's caller
// might have adjusted vk, namely to make it a left/right specific modifier key rather than a
// neutral one.
{
	// See above notes near the first mention of SHIFT_KEY_WORKAROUND_TIMEOUT for details.
	// This part of the workaround can be tested via "NumpadEnd::KeyHistory".  Turn on numlock,
	// hold down shift, and press numpad1. The hotkey will fire and the status should display
	// that the shift key is physically, but not logically down at that exact moment:
	if (prior_event_was_physical && (prior_vk == VK_LSHIFT || prior_vk == VK_SHIFT)  // But not RSHIFT.
		&& (DWORD)(GetTickCount() - prior_event_tickcount) < (DWORD)SHIFT_KEY_WORKAROUND_TIMEOUT)
	{
		bool current_is_dual_state = IsDualStateNumpadKey(vk, sc);
		// Verified: Both down and up events for the *current* (not prior) key qualify for this:
		bool fix_it = (!prior_event_was_key_up && DualStateNumpadKeyIsDown())  // Case #4 of the workaround.
			|| (prior_event_was_key_up && key_up && current_is_dual_state); // Case #5
		if (fix_it)
			next_phys_shift_down_is_not_phys = true;
		// In the first case, both the numpad key-up and down events are eligible:
		if (   fix_it || (prior_event_was_key_up && current_is_dual_state)   )
		{
			// Since the prior event (the shift key) already happened (took effect) and since only
			// now is it known that it shouldn't have been physical, undo the effects of it having
			// been physical:
			g_modifiersLR_physical = prior_modifiersLR_physical;
			g_PhysicalKeyState[VK_SHIFT] = prior_shift_state;
			g_PhysicalKeyState[VK_LSHIFT] = prior_lshift_state;
		}
	}


	// Must do this part prior to UpdateModifierState() because we want to store the values
	// as they are prior to the potentially-erroneously-physical shift key event takes effect.
	// The state of these is also saved because we can't assume that a shift-down, for
	// example, CHANGED the state to down, because it may have been already down before that:
	prior_modifiersLR_physical = g_modifiersLR_physical;
	prior_shift_state = g_PhysicalKeyState[VK_SHIFT];
	prior_lshift_state = g_PhysicalKeyState[VK_LSHIFT];

	// If this function was called from SuppressThisKey(), these comments apply:
	// Currently SuppressThisKey is only called with a modifier in the rare case
	// when disguise_next_lwin/rwin_up is in effect.  But there may be other cases in the
	// future, so we need to make sure the physical state of the modifiers is updated
	// in our tracking system even though the key is being suppressed:
	if (kvk[vk].as_modifiersLR)
		UpdateModifierState(event, vk, sc, key_up, aIsSuppressed);  // Update our tracking of LWIN/RWIN/RSHIFT etc.

	// Now that we're done using the old values (the above used them and also UpdateModifierState()'s
	// calls to EventIsPhysical()), update these to their new values:
	prior_vk = vk;
	prior_sc = sc;
	prior_event_was_key_up = key_up;
	prior_event_was_physical = EventIsPhysical(event, vk, sc, key_up);
	prior_event_tickcount = GetTickCount();
}
#endif // Keyboard hook