유리상자 속 이야기

#pragma once


HHOOK hKeyboardHook = NULL;
HINSTANCE g_Module = NULL;
HOOKPROC g_callback = NULL;


LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam);

#ifdef __cplusplus
extern "C" {
#endif

__declspec(dllexport) bool StartHook(HOOKPROC proc);
__declspec(dllexport) bool StopHook();
#ifdef __cplusplus
}
#endif

#include <iostream>
#include "windows.h"
#include "KeyboardHook.h"

using namespace std;


BOOL APIENTRY DllMain( HANDLE hModule, DWORD  dwReason, LPVOID lpReserved)
{
	switch (dwReason)
	{
	case DLL_PROCESS_ATTACH:
		g_Module = (HINSTANCE)hModule; // Save Dll Handle
		break; 
	case DLL_PROCESS_DETACH:
		StopHook();
		g_Module = NULL;
		break;
	}
	return TRUE;
}


bool StartHook(HOOKPROC proc)
{
	if(hKeyboardHook != NULL) { return false; }

	g_callback = proc;
	hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardProc, g_Module, 0);
	return (hKeyboardHook != NULL);
}



bool StopHook()
{
	if(hKeyboardHook == NULL) { return false; }

	if(UnhookWindowsHookEx(hKeyboardHook) == TRUE) { //제거
		hKeyboardHook = NULL;
	}
	return (hKeyboardHook == NULL);
}


LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{ 
	
	if(hKeyboardHook != NULL) {
		// -1 이 리턴되면 NextHook 호출 안함
		if(g_callback(nCode, wParam, lParam) == -1) {
			return -1;
		}
	}
	return ::CallNextHookEx(hKeyboardHook, nCode, wParam, lParam); 
}