Function UpdateKeybdState

source/hook.cpp:3095–3196

void UpdateKeybdState(KBDLLHOOKSTRUCT &aEvent, const vk_type aVK, const sc_type aSC, bool aKeyUp, bool aIsSuppressed)
// Caller has ensured that vk has been translated from neutral to left/right if necessary.
// 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.
{
	// If this function was called from SuppressThisKey(), these comments apply:
	// Currently SuppressThisKey is only called with a modifier in the rare case
	// when sDisguiseNextLWinUp/RWinUp 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:
	modLR_type modLR;
	if (modLR = kvk[aVK].as_modifiersLR) // Update our tracking of LWIN/RWIN/RSHIFT etc.
	{
		// Caller has ensured that vk has been translated from neutral to left/right if necessary
		// (e.g. VK_CONTROL -> VK_LCONTROL). For this reason, always use the parameter vk rather
		// than the raw event.vkCode.
		// Below excludes KEY_IGNORE_ALL_EXCEPT_MODIFIER since that type of event shouldn't be ignored by
		// this function.  UPDATE: KEY_PHYS_IGNORE is now considered to be something that shouldn't be
		// ignored in this case because if more than one instance has the hook installed, it is
		// possible for g_modifiersLR_logical_non_ignored to say that a key is down in one instance when
		// that instance's g_modifiersLR_logical doesn't say it's down, which is definitely wrong.  So it
		// is now omitted below:
		bool is_not_ignored = (aEvent.dwExtraInfo != KEY_IGNORE);
		bool is_fake_shift = aEvent.scanCode == SC_FAKE_LSHIFT || aEvent.scanCode == SC_FAKE_RSHIFT;
		bool is_fake_ctrl = aEvent.scanCode == SC_FAKE_LCTRL; // AltGr.
		// For backward-compatibility, fake LCtrl is marked as physical.
		bool event_is_physical = !is_fake_shift && KeybdEventIsPhysical(aEvent.flags, aVK, aKeyUp);

		if (aKeyUp)
		{
			// Keep track of system-generated Shift-up events (as part of a workaround for
			// Shift becoming stuck due to interaction between Send and the system handling
			// of shift-numpad combinations).  Find "fake shift" for more details.
			if (is_fake_shift)
				g_modifiersLR_numpad_mask |= modLR;
			if (!aIsSuppressed)
			{
				g_modifiersLR_logical &= ~modLR;
				// Even if is_not_ignored == true, this is updated unconditionally on key-up events
				// to ensure that g_modifiersLR_logical_non_ignored never says a key is down when
				// g_modifiersLR_logical says its up, which might otherwise happen in cases such
				// as alt-tab.  See this comment further below, where the operative word is "relied":
				// "key pushed ALT down, or relied upon it already being down, so go up".  UPDATE:
				// The above is no longer a concern because KeyEvent() now defaults to the mode
				// which causes our var "is_not_ignored" to be true here.  Only the Send command
				// overrides this default, and it takes responsibility for ensuring that the older
				// comment above never happens by forcing any down-modifiers to be up if they're
				// not logically down as reflected in g_modifiersLR_logical.  There's more
				// explanation for g_modifiersLR_logical_non_ignored in keyboard_mouse.h:
				if (is_not_ignored)
					g_modifiersLR_logical_non_ignored &= ~modLR;
			}
			if (event_is_physical) // Note that ignored events can be physical via KEYEVENT_PHYS()
			{
				g_modifiersLR_physical &= ~modLR;
				g_PhysicalKeyState[aVK] = 0;
				if (!is_fake_ctrl)