Untitled

// syshook.cpp
/*
 *      SysHook - 7/17/05
 *      Jacob Gohlke
 *
 *      JNI Interface for setting a Keyboard Hook and monitoring
 *      it Java-side
 *
 *      (c) Copyright 2005 Jacob Gohlke
 *
 *      Feel free to use and learn from this code, royalty-free!
 *      I only ask you acknkowlege what library you are using
 *      and who made it. Thanks, and happy hooking!
 */

#include <windows.h>
#include <winuser.h>
#include "jni.h"
#include "syshook.h"

#pragma data_seg(".HOOKDATA") //Shared data among all instances.
static HHOOK hkb = NULL;
static HANDLE g_hModule = NULL;
static WPARAM g_wParam = NULL;
static LPARAM g_lParam = NULL;

JNIEXPORT void NotifyJava(JNIEnv *env, jobject obj, WPARAM wParam, LPARAM lParam)
{
        jclass cls = env->GetObjectClass(obj);
        jmethodID mid;

        mid = env->GetMethodID(cls, "Callback", "(ZIZZ)V");
        if (mid == NULL)
                        return;

        if( (HIWORD( lParam ) & KF_UP) )
                env->CallVoidMethod(obj, mid, (jboolean)FALSE, (jint)(wParam), (jboolean)(HIWORD( lParam ) & KF_ALTDOWN), (jboolean)(HIWORD( lParam ) & KF_EXTENDED));
        else
                env->CallVoidMethod(obj, mid, (jboolean)TRUE, (jint)(wParam), (jboolean)(HIWORD( lParam ) & KF_ALTDOWN), (jboolean)(HIWORD( lParam ) & KF_EXTENDED));
}

#pragma data_seg()

#pragma comment(linker, "/SECTION:.HOOKDATA,RWS")

JNIEXPORT LRESULT CALLBACK HookKeyboardProc(INT nCode, WPARAM wParam, LPARAM lParam)
{
    if (nCode < 0)  // do not process message
                return CallNextHookEx(hkb, nCode, wParam, lParam);

        g_wParam = wParam;
        g_lParam = lParam;
        return CallNextHookEx(hkb, nCode, wParam, lParam);
}

JNIEXPORT void JNICALL Java_PollThread_checkKeyboardChanges(JNIEnv *env, jobject obj)
{
        if(g_wParam != NULL && g_lParam != NULL)
        {
                NotifyJava(env, obj, g_wParam, g_lParam);
                g_wParam = NULL;
                g_lParam = NULL;
        }
}

static void Init()
{
        hkb = SetWindowsHookEx( WH_KEYBOARD, (HOOKPROC)HookKeyboardProc, (HINSTANCE)g_hModule, 0 );
}

static void Cleanup()
{
        if( hkb != NULL )
                UnhookWindowsHookEx( hkb );

        hkb = NULL;
}

BOOL APIENTRY DllMain( HANDLE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved )
{
        switch(ul_reason_for_call)
        {
                case DLL_PROCESS_ATTACH:
                        g_hModule = hModule;
                        Init();
                        return TRUE;

                case DLL_PROCESS_DETACH:
                        Cleanup();
                        return TRUE;
        }

    return TRUE;
}