libwin32/lib/win32/user32/class.js

Node bindings to native Win32 DLLs through Koffi

import koffi from 'koffi-cream';
import { StringOutputBuffer } from '../private.js';
import { cBOOL, cINT, cPVOID, cSTR, cATOM, cHANDLE } from '../ctypes.js';
import { cWNDCLASS, cWNDCLASSEX, WNDCLASSEX, cWNDPROC } from '../structs.js';
import { user32 } from './lib.js';
const wndProcs = new Map();
/**
 * Retrieves information about a window class.
 *
 * Note: libwin32 only supports querying by class name (string).
 *
 * https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getclassinfow
 */
export function GetClassInfo(hInstance, className) {
    GetClassInfo.native ??= user32.func('GetClassInfoW', cBOOL, [cHANDLE, cSTR, koffi.out(koffi.pointer(cWNDCLASS))]);
    const wndClass = {};
    return GetClassInfo.native(hInstance, className, wndClass) !== 0 ? wndClass : null;
}
/**
 * Retrieves information about a window class, including a handle to the small icon associated with the window class.
 *
 * Note: libwin32 only supports querying by class name (string).
 *
 * https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getclassinfoexw
 */
export function GetClassInfoEx(hInstance, className) {
    GetClassInfoEx.native ??= user32.func('GetClassInfoExW', cBOOL, [cHANDLE, cSTR, koffi.out(koffi.pointer(cWNDCLASSEX))]);
    const wndClassEx = new WNDCLASSEX();
    return GetClassInfoEx.native(hInstance, className, wndClassEx) !== 0 ? wndClassEx : null;
}
/**
 * Retrieves the name of the class to which the specified window belongs.
 *
 * https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getclassnamew
 */
export function GetClassName(hWnd) {
    GetClassName.native ??= user32.func('GetClassNameW', cINT, [cHANDLE, koffi.out(cPVOID), cINT]);
    const className = new StringOutputBuffer(256);
    const len = GetClassName.native(hWnd, className.buffer, className.length);
    return len ? className.decode(len) : null;
}
/**
 * Registers a window class for subsequent use in calls to the CreateWindow function.
 *
 * https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-registerclassw
 */
export function RegisterClass(wndClass) {
    RegisterClass.native ??= user32.func('RegisterClassW', cATOM, [koffi.pointer(cWNDCLASS)]);
    let wndProc;
    if (typeof wndClass.lpfnWndProc === 'function') {
        wndProc = koffi.register(wndClass.lpfnWndProc, cWNDPROC);
        wndClass = {
            ...wndClass,
            lpfnWndProc: wndProc
        };
    }
    const atom = RegisterClass.native(wndClass);
    return atom
        ? (wndProcs.set(atom, wndProc), atom)
        : (wndProc && koffi.unregister(wndProc), null);
}
/**
 * Registers a window class for subsequent use in calls to the CreateWindowEx function.
 *
 * https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-registerclassexw
 */
export function RegisterClassEx(wndClassEx) {
    RegisterClassEx.native ??= user32.func('RegisterClassExW', cATOM, [koffi.pointer(cWNDCLASSEX)]);
    let wndProc;
    if (typeof wndClassEx.lpfnWndProc === 'function') {
        wndProc = koffi.register(wndClassEx.lpfnWndProc, cWNDPROC);
        wndClassEx = {
            ...wndClassEx,
            lpfnWndProc: wndProc
        };
    }
    const atom = RegisterClassEx.native(wndClassEx);
    return atom
        ? (wndProcs.set(atom, wndProc), atom)
        : (wndProc && koffi.unregister(wndProc), null);
}
/**
 * Unregisters a window class, freeing the memory required for the class.
 *
 * Note: despite the parameter being named `className`, as in the native API,
 *       libwin32 only supports unregistering by ATOM -- the one you received
 *       from RegisterClass/RegisterClassEx.
 *
 * https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-unregisterclassw
 */
export function UnregisterClass(className, hInstance = null) {
    UnregisterClass.native ??= user32.func('UnregisterClassW', cBOOL, [cATOM, cHANDLE]);
    const ret = UnregisterClass.native(className, hInstance) !== 0;
    if (ret) {
        const wndProc = wndProcs.get(className);
        if (wndProc) {
            koffi.unregister(wndProc);
            wndProcs.delete(className);
        }
    }
    return ret;
}
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