minecjk.c

/* MineCJK 0.1 */

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <jni.h>
#include <stdio.h>
#include <stdlib.h>
#include "MineCJK.h"

static JavaVM *jvm;
static int ime_codepage;

typedef struct {
    jclass WindowsDisplay;                  /* of org.lwjgl.opengl */
	jclass WindowsImplementation;           /* of org.mearie.minecjk */
} userdata_t;


static void minecjk_set_ime_codepage(HKL kbdlayout)
{
	char buf[20];
	GetLocaleInfo(LOWORD(kbdlayout), LOCALE_IDEFAULTANSICODEPAGE,
		buf, sizeof buf);
	ime_codepage = atoi(buf);
}

static wchar_t minecjk_ime_codepage_to_unicode(WPARAM wParam)
{
	char buf[2];
	wchar_t wbuf[1];
	int buflen;

	if (wParam & 0xff00) {
		buf[0] = (unsigned char)(wParam >> 8);
		buf[1] = (unsigned char)wParam;
		buflen = 2;
	} else {
		buf[0] = (unsigned char)wParam;
		buflen = 1;
	}

	if (!MultiByteToWideChar(ime_codepage,
			MB_COMPOSITE|MB_ERR_INVALID_CHARS,
			buf, buflen, wbuf, 1)) {
		return (wchar_t)0xfffd;
	} else {
		return wbuf[0];
	}
}

static LRESULT CALLBACK minecjk_wndproc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	JNIEnv *env;
	userdata_t *ud;
	LONG msgtime;
	jmethodID handler;

	if ((*jvm)->GetEnv(jvm, (void *)&env, JNI_VERSION_1_4)) goto fallback;
	if (env == NULL || (*env)->ExceptionOccurred(env)) goto fallback;

	ud = (userdata_t*)(LONG_PTR)GetWindowLongPtr(hwnd, GWLP_USERDATA);
	if (ud == NULL) goto fallback;

	switch (msg) {
	case WM_INPUTLANGCHANGE:
		minecjk_set_ime_codepage((HKL)lParam);
		return 0;

	case WM_IME_STARTCOMPOSITION: {
		HIMC imc = ImmGetContext(hwnd);
		COMPOSITIONFORM cf;
		RECT workarea;

		/* move the composition window out of screen */
		SystemParametersInfo(SPI_GETWORKAREA, 0, (void*)&workarea, 0);
		cf.dwStyle = CFS_POINT;
		cf.ptCurrentPos.x = 0;
		cf.ptCurrentPos.y = workarea.bottom + 64;
		ImmSetCompositionWindow(imc, &cf);
		ImmReleaseContext(hwnd, imc);

		handler = (*env)->GetStaticMethodID(env,
			ud->WindowsImplementation, "startComposition", "()V");
		if (handler == NULL) goto fallback;
		(*env)->CallStaticVoidMethod(env, ud->WindowsImplementation, handler);
		return 0;
	}

	case WM_IME_ENDCOMPOSITION:
		handler = (*env)->GetStaticMethodID(env,
			ud->WindowsImplementation, "endComposition", "()V");
		if (handler == NULL) goto fallback;
		(*env)->CallStaticVoidMethod(env, ud->WindowsImplementation, handler);
		return 0;

	case WM_IME_COMPOSITION: {
		if (lParam & GCS_COMPSTR) {
			HIMC imc = ImmGetContext(hwnd);
			int n = ImmGetCompositionStringW(imc, GCS_COMPSTR, NULL, 0);
			if (n <= 0) {
				ImmReleaseContext(hwnd, imc);
				goto fallback;
			}

			wchar_t buf[(n - 1) / sizeof(wchar_t) + 1];
			jstring str;
			ImmGetCompositionStringW(imc, GCS_COMPSTR, buf, n);
			n = (n - 1) / sizeof(wchar_t) + 1;

			handler = (*env)->GetStaticMethodID(env,
				ud->WindowsImplementation, "updateComposingString",
				"(Ljava/lang/String;)V");
			if (handler == NULL) {
				ImmReleaseContext(hwnd, imc);
				goto fallback;
			}

			str = (*env)->NewString(env, (jchar*)buf, n);
			if (str == NULL) {
				ImmReleaseContext(hwnd, imc);
				goto fallback;
			}
			(*env)->CallStaticVoidMethod(env, ud->WindowsImplementation,
				handler, str);

			ImmReleaseContext(hwnd, imc);
			return 0;
		}
		break;
	}

	case WM_IME_CHAR:
		msgtime = GetMessageTime();
		wParam = (WPARAM)minecjk_ime_codepage_to_unicode(wParam);

		/* we are going to be more hairy. lwjgl lacks the proper Unicode
		 * support until very recently (svn r3616), so we cannot directly
		 * use its own message handler. */
		handler = (*env)->GetStaticMethodID(env,
			ud->WindowsImplementation, "handleChar", "(JJJ)I");
		if (handler == NULL) goto fallback;
		return (*env)->CallStaticIntMethod(env,
			ud->WindowsImplementation, handler,
			(jlong)wParam, (jlong)lParam, (jlong)msgtime);

	default:
		msgtime = GetMessageTime();

		handler = (*env)->GetStaticMethodID(env, ud->WindowsDisplay,
			"handleMessage", "(JIJJJ)I");
		if (handler == NULL) goto fallback;
		return (*env)->CallStaticIntMethod(env, ud->WindowsDisplay,
			handler, (jlong)(intptr_t)hwnd, (jint)msg,
			(jlong)wParam, (jlong)lParam, (jlong)msgtime);
	}

fallback:
	return DefWindowProc(hwnd, msg, wParam, lParam);
}


JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved)
{
	(void)reserved;
	jvm = vm;
	minecjk_set_ime_codepage(GetKeyboardLayout(0));
	return JNI_VERSION_1_4;
}

JNIEXPORT void JNICALL JNI_OnUnload(JavaVM *vm, void *reserved)
{
	(void)vm;
	(void)reserved;
}

JNIEXPORT jboolean JNICALL Java_org_mearie_minecjk_WindowsImplementation_replaceWindowProc(JNIEnv *env, jclass unused)
{
	jclass dispcls, implcls, winimplcls;
	jobject impl;
	jmethodID getimpl, gethwnd;
	HWND hwnd;
	userdata_t *ud;

	(void)unused;

	/* yes, we are cheating a lot. */
	dispcls = (*env)->FindClass(env, "org/lwjgl/opengl/Display");
	if (dispcls == NULL) return JNI_FALSE;
	getimpl = (*env)->GetStaticMethodID(env, dispcls, "getImplementation",
		"()Lorg/lwjgl/opengl/DisplayImplementation;");
	if (getimpl == NULL) return JNI_FALSE;
	impl = (*env)->CallStaticObjectMethod(env, dispcls, getimpl);
	if (impl == NULL) return JNI_FALSE;
	implcls = (*env)->FindClass(env, "org/lwjgl/opengl/WindowsDisplay");
	if (implcls == NULL) return JNI_FALSE;
	gethwnd = (*env)->GetMethodID(env, implcls, "getHwnd", "()J");
	if (gethwnd == NULL) return JNI_FALSE;
	hwnd = (HWND)(*env)->CallLongMethod(env, impl, gethwnd);

	winimplcls = (*env)->FindClass(env, "org/mearie/minecjk/WindowsImplementation");
	if (winimplcls == NULL) return JNI_FALSE;
	winimplcls = (*env)->NewGlobalRef(env, winimplcls);
	if (winimplcls == NULL) return JNI_FALSE;

	ud = malloc(sizeof(userdata_t));
	if (ud == NULL) return JNI_FALSE;
	/* unlike lwjglWindowProc, this function is called long after the initial
	 * message (that is, WM_CREATE). so we are certain that the jclass pointed
	 * by GWLP_USERDATA is initialized. */
	ud->WindowsDisplay = (jclass)(LONG_PTR)GetWindowLongPtr(hwnd, GWLP_USERDATA);
	ud->WindowsImplementation = winimplcls;

	SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR)&minecjk_wndproc);
	SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR)ud);
	return JNI_TRUE;
}