_ff-addon-snippet-WinAPI-ShowWindowHide - Using js-ctypes and WinAPI method of ShowWindow to hide a window. [windows] [jsctypes]

_ff-addon-snippet-WinAPI-ShowWindowHide.js

Cu.import('resource://gre/modules/ctypes.jsm')

var wintypesInit = function() {	
	// BASIC TYPES (ones that arent equal to something predefined by me)
	this.BOOL = ctypes.bool;
	this.HWND = ctypes.voidptr_t;
	this.INT = ctypes.int;

	// CONSTANTS
	this.SW_HIDE = 0;
	this.SW_SHOW = 5;
}
var ostypes = new wintypesInit();

// start - skeleton, shouldn't have to edit
var lib = {};
function _lib(path) {
	//ensures path is in lib, if its in lib then its open, if its not then it adds it to lib and opens it. returns lib
	//path is path to open library
	//returns lib so can use straight away

	if (!(path in lib)) {
		//need to open the library
		//default it opens the path, but some things are special like libc in mac is different then linux or like x11 needs to be located based on linux version
		switch (path) {
			default:
				try {
					lib[path] = ctypes.open(path);
				} catch (e) {
					console.error('Integration Level 1: Could not get open path:', path, 'e:' + e);
					throw new Error('Integration Level 1: Could not get open path:"' + path + '" e: "' + e + '"');
				}
		}
	}
	return lib[path];
}

var dec = {};
function _dec(declaration) { // it means ensureDeclared and return declare. if its not declared it declares it. else it returns the previously declared.
	if (!(declaration in dec)) {
		dec[declaration] = preDec[declaration](); //if declaration is not in preDec then dev messed up
	}
	return dec[declaration];
}
// end - skeleton, shouldn't have to edit

// start - predefine your declares here
var preDec = { //stands for pre-declare (so its just lazy stuff) //this must be pre-populated by dev // do it alphabateized by key so its ez to look through
	ShowWindow: function() {
		/* https://msdn.microsoft.com/en-us/library/windows/desktop/ms633548%28v=vs.85%29.aspx
		 * BOOL WINAPI ShowWindow(
		 *   __in_  HWND hWnd,
		 *   __in_  int nCmdShow
		 * );
		 */
		return _lib('user32.dll').declare('ShowWindow', ctypes.winapi_abi,
			ostypes.BOOL,	// return
			ostypes.HWND,	// hWnd
			ostypes.INT		// nCmdShow
		);
	}
}
// end - predefine your declares here

// start - helper functions

// end - helper functions

function shutdown() {
	// do in here what you want to do before shutdown
	
	for (var l in lib) {
		lib[l].close();
	}
}

function main() {
	//do code here
	
	// get hwnd
	var browserWindow = Services.wm.getMostRecentWindow('navigator:browser');
	if (!browserWindow) {
		throw new Error('No browser window found');
	}
	var baseWindow = browserWindow.QueryInterface(Ci.nsIInterfaceRequestor)
								  .getInterface(Ci.nsIWebNavigation)
								  .QueryInterface(Ci.nsIDocShellTreeItem)
								  .treeOwner
								  .QueryInterface(Ci.nsIInterfaceRequestor)
								  .getInterface(Ci.nsIBaseWindow);
								  
	var hwndString = baseWindow.nativeHandle;
	var hwnd = ctypes.voidptr_t(ctypes.UInt64(hwndString));
	// end get hwnd
	
	var rez_ShowWindow = _dec('ShowWindow')(hwnd, ostypes.SW_HIDE);
	console.info('rez_ShowWindow:', rez_ShowWindow, rez_ShowWindow.toString(), uneval(rez_ShowWindow));
	if (rez_ShowWindow == true) {
		console.log('window succesfully hidden');
	} else if (rez_ShowWindow == false) {
		console.warn('window failed to hide, it may already be hidden');
	} else {
		throw new Error('ShowWindow returned not false or true, this should never happen, if it did it should crash');
	}
}

try {
	main();
} catch(ex) {
	throw ex;
} finally {
	shutdown();
}

README

Rev1

• Works - hides window from taskbar also
• Following X11_Base structure/abstraction layer
• Important note, I may need to hook the window to keep it hidden, apparently windows receive messages a lot and it will be shown again after some time, so instead of continually sending the hide message we have to hook the window with SetWindowHookEx and watch for message of WM_WINDOWPOSCHANGING and apply the hide again to ensure it reamins hidden
  • Source: StackOverflow :: Prevent window from being shown by another application
  • I tested this code using Windows 8.1 and I didn't see this reappearing behavior so I didn't bother with coding the hooking method, but if anyone else reports this to be true let's write up a hooking method

Same code as Rev1 just with the abstraction layer removed:

Cu.import('resource://gre/modules/ctypes.jsm')
var user32 = ctypes.open('user32.dll');
var TYPES = {
    BOOL: ctypes.bool,
    HWND: ctypes.voidptr_t,
    INT: ctypes.int
};
var CONSTS = {
    SW_HIDE: 0,
    SW_SHOW: 5
};
var ShowWindow = user32.declare('ShowWindow', ctypes.winapi_abi, TYPES.BOOL, TYPES.HWND, TYPES.INT);


    // get hwnd
    var browserWindow = Services.wm.getMostRecentWindow('navigator:browser');
    if (!browserWindow) {
        throw new Error('No browser window found');
    }
    var baseWindow = browserWindow.QueryInterface(Ci.nsIInterfaceRequestor)
                                  .getInterface(Ci.nsIWebNavigation)
                                  .QueryInterface(Ci.nsIDocShellTreeItem)
                                  .treeOwner
                                  .QueryInterface(Ci.nsIInterfaceRequestor)
                                  .getInterface(Ci.nsIBaseWindow);

    var hwndString = baseWindow.nativeHandle;
    var hwnd = ctypes.voidptr_t(ctypes.UInt64(hwndString));
    // end get hwnd

    var rez_ShowWindow = ShowWindow(hwnd, CONSTS.SW_HIDE);
    console.info('rez_ShowWindow:', rez_ShowWindow, rez_ShowWindow.toString(), uneval(rez_ShowWindow));
    if (rez_ShowWindow == true) {
        console.log('window succesfully hidden');
    } else if (rez_ShowWindow == false) {
        console.warn('window failed to hide, it may already be hidden');
    } else {
        throw new Error('ShowWindow returned not false or true, this should never happen, if it did it should crash');
    }

user32.close();