Function HookThreadProc

source/hook.cpp:4243–4332

DWORD WINAPI HookThreadProc(LPVOID aUnused)
// The creator of this thread relies on the fact that this function always exits its thread
// when both hooks are deactivated.
{
	MSG msg;
	bool problem_activating_hooks;

	for (;;) // Infinite loop for pumping messages in this thread. This thread will exit via any use of "return" below.
	{
		if (GetMessage(&msg, NULL, 0, 0) == -1) // -1 is an error, 0 means WM_QUIT.
			continue; // Probably happens only when bad parameters are passed to GetMessage().

		switch (msg.message)
		{
		case WM_QUIT:
			// After this message, fall through to the next case below so that the hooks will be removed before
			// exiting this thread.
			msg.wParam = 0; // Indicate to AHK_CHANGE_HOOK_STATE that both hooks should be deactivated.
		// ********
		// NO BREAK IN ABOVE, FALL INTO NEXT CASE:
		// ********
		case AHK_CHANGE_HOOK_STATE: // No blank line between this in the above to indicate fall-through.
			// In this case, wParam contains the bitwise set of hooks that should be active.
			problem_activating_hooks = false;
			if (msg.wParam & HOOK_KEYBD) // Activate the keyboard hook (if it isn't already).
			{
				if (!g_KeybdHook)
				{
					// v1.0.39: Reset *before* hook is installed to avoid any chance that events can
					// flow into the hook prior to the reset:
					if (msg.lParam) // Sender of msg. is signaling that reset should be done.
						ResetHook(false, HOOK_KEYBD, true);
					if (   !(g_KeybdHook = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeybdProc, g_hInstance, 0))   )
						problem_activating_hooks = true;
				}
			}
			else // Caller specified that the keyboard hook is to be deactivated (if it isn't already).
				if (g_KeybdHook)
					if (UnhookWindowsHookEx(g_KeybdHook))
						g_KeybdHook = NULL;

			if (msg.wParam & HOOK_MOUSE) // Activate the mouse hook (if it isn't already).
			{
				if (!g_MouseHook)
				{
					if (msg.lParam) // Sender of msg. is signaling that reset should be done.
						ResetHook(false, HOOK_MOUSE, true);
					if (   !(g_MouseHook = SetWindowsHookEx(WH_MOUSE_LL, LowLevelMouseProc, g_hInstance, 0))   )
						problem_activating_hooks = true;
				}
			}
			else // Caller specified that the mouse hook is to be deactivated (if it isn't already).
				if (g_MouseHook)
					if (UnhookWindowsHookEx(g_MouseHook))
						g_MouseHook = NULL;

			// Upon failure, don't display MsgBox here because although MsgBox's own message pump would
			// service the hook that didn't fail (if it's active), it's best to avoid any blocking calls