_ff-addon-snippet-ObjC-NSNotificationApplicationWillLaunch - Uses the [[NSWorkspace sharedWorkspace] notificationCenter] to watch when applications launch. [objective-c] [osx] [js-ctypes

_ff-addon-snippet-ObjC-NSNotificationApplicationWillLaunch.js

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

var objc = ctypes.open(ctypes.libraryName('objc'));

// BASIC TYPES
var BOOL = ctypes.signed_char;
var CHAR = ctypes.char;
var CLASS = ctypes.voidptr_t;
var ID = ctypes.voidptr_t;
var NSNOTIFICATIONPTR = ctypes.voidptr_t;
var SEL = ctypes.voidptr_t;
var SIZE_T = ctypes.size_t
var VOID = ctypes.void_t;

// ADVANCED TYPES
var IMP_for_notif_cb = ctypes.FunctionType(ctypes.default_abi, VOID, [ID, SEL, NSNOTIFICATIONPTR]).ptr; //repalced variadic with ID as its specific to my use otherwise doing class_addMethod throws error saying expected pointer blah blah //ctypes.FunctionType(ctypes.default_abi, ID, [ID, SEL, '...']).ptr;

// CONSTANTS
var NIL = ctypes.cast(ctypes.uint64_t(0x0), ctypes.voidptr_t);

// COMMON FUNCTIONS
var class_addMethod = objc.declare('class_addMethod', ctypes.default_abi, BOOL, CLASS, SEL, IMP_for_notif_cb, CHAR.ptr);
var objc_allocateClassPair = objc.declare('objc_allocateClassPair', ctypes.default_abi, CLASS, CLASS, CHAR.ptr, SIZE_T);
var objc_disposeClassPair = objc.declare('objc_disposeClassPair', ctypes.default_abi, VOID, CLASS);
var objc_getClass = objc.declare('objc_getClass', ctypes.default_abi, ID, CHAR.ptr);
var objc_msgSend = objc.declare('objc_msgSend', ctypes.default_abi, ID, ID, SEL, '...');
var objc_registerClassPair = objc.declare('objc_registerClassPair', ctypes.default_abi, VOID, CLASS);
var sel_registerName = objc.declare('sel_registerName', ctypes.default_abi, SEL, CHAR.ptr);

// COMMON SELECTORS
var alloc = sel_registerName('alloc');
var init = sel_registerName('init');
var release = sel_registerName('release');

// my personal globals for this code
var NoitNotifCB_imp; // important to make this global otherwise on callback trigger firefox will crash, because this got GC'ed before calback triggered
var releaseThese = [];
var shutdown = function() {
	for (var i=0; i<releaseThese.length; i++) {
		objc_msgSend(releaseThese[i], release);
	}
	
	objc.close();
	
	console.log('succesfully shutdown');
}

function main() {
	
	// the reason i create the class first is because it starts off by running objc_allocateClassPair, if that errors, then that means theres no need to continue and do teh other stuff, that will mess up the unloadings in shutdown() and it wont shutdown properly, this was evident because i ran this code again and it couldn't allocate even after i ran shutdown(). well actually shutdown() didnt shutdown properly on consequent run because i redefined `var shutdown` before running main so duh tahts what broke it. but i would still like to place this first because then i dont unnecessarily allocate an extra NSString etc.
	// start - create class and callback
	var NSObject = objc_getClass('NSObject');
	var NoitNotifCls_class = objc_allocateClassPair(NSObject, 'NoitNotifCls', 0);
	console.info('NoitNotifCls_class:', NoitNotifCls_class, NoitNotifCls_class.toString(), uneval(NoitNotifCls_class), NoitNotifCls_class.isNull());
	if (NoitNotifCls_class.isNull()) {
		throw new Error('NoitNotifCls_class is NIL, so objc_allocateClassPair failed. objc_registerClassPair likely already ran prior to this on NoitNoitfCls_class and objc_disposeOfClassPair was not yet run on NoitNoitfCls_class'); // this happens on consequent runs after `objc_registerClassPair` is run on `NoitNotifCls_class`
	}

	function NoitNotifCB_js(c_arg1__self, c_arg2__sel, objc_arg1_NSNOTIFICATIONPTR) {
		console.log('NoitNotifCB_js Triggered');
		return NIL;
	}
	
	NoitNotifCB_imp = IMP_for_notif_cb(NoitNotifCB_js);
	
	var NoitNotifCB_selector = sel_registerName('NoitNoitfCB_objc');
	var rez_class_addMethod = class_addMethod(NoitNotifCls_class, NoitNotifCB_selector, NoitNotifCB_imp, 'v@:@'); // because return of callback is void, first argument is c_arg1__self which is `id` and c_arg2__id sel `SEL` and objc_arg1__NSNotificationPtr is `voidptr_t` // so per this page: https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html#//apple_ref/doc/uid/TP40008048-CH100 // and this chat: https://gist.github.com/Noitidart/21b202611c62d74fecd0
	console.info('rez_class_addMethod:', rez_class_addMethod, rez_class_addMethod.toString(), uneval(rez_class_addMethod));
	if (rez_class_addMethod != 1) {
		throw new Error('rez_class_addMethod is not 1, so class_addMethod failed');
	}

	objc_registerClassPair(NoitNotifCls_class); // returns void // once this line runs ,running objc_allocateClassPair on NoiTNotifCls_class will result it in being NIL

	var NoitNotifCls_instance = objc_msgSend(objc_msgSend(NoitNotifCls_class, alloc), init); // if don't do alloc init on NoitNotifCls_class then the NoitNotifCB_js never triggers
	console.info('NoitNotifCls_instance:', NoitNotifCls_instance, NoitNotifCls_instance.toString(), uneval(NoitNotifCls_instance), NoitNotifCls_instance.isNull());
	releaseThese.push(NoitNotifCls_instance);
	// end - create class and callback
	
	// notif_name = [[NSString initWithUTF8String:] 'NSWorkspaceWillLaunchApplicationNotification'];
	var jsStr_notifName = 'NSWorkspaceWillLaunchApplicationNotification';
	var NSString = objc_getClass('NSString');
	var initWithUTF8String = sel_registerName('initWithUTF8String:');
	var nsworkspace_will_launch_application_notification = objc_msgSend(objc_msgSend(NSString, alloc), initWithUTF8String, CHAR.array()(jsStr_notifName));
	console.info('nsworkspace_will_launch_application_notification:', nsworkspace_will_launch_application_notification, nsworkspace_will_launch_application_notification.toString(), uneval(nsworkspace_will_launch_application_notification));
	releaseThese.push(nsworkspace_will_launch_application_notification);
	
	/*
	// default_center = [NSDistributedNotificationCenter defaultCenter];
	var NSDistributedNotificationCenter = objc_getClass('NSDistributedNotificationCenter');
	var defaultCenter = sel_registerName('defaultCenter');
	var default_center = objc_msgSend(NSDistributedNotificationCenter, defaultCenter);
	console.info('default_center:', default_center, default_center.toString(), uneval(default_center), default_center.isNull());
	*/
	
	// shared_workspace = [NSWorkspace sharedWorkspace];
	var NSWorkspace = objc_getClass('NSWorkspace');
	var sharedWorkspace = sel_registerName('sharedWorkspace');
	var shared_workspace = objc_msgSend(NSWorkspace, sharedWorkspace);
	console.info('shared_workspace:', shared_workspace, shared_workspace.toString(), uneval(shared_workspace), shared_workspace.isNull());

	// notification_center = [[NSWorkspace sharedWorkspace] notificationCenter];
	var notificationCenter = sel_registerName('notificationCenter');
	var notification_center = objc_msgSend(shared_workspace, notificationCenter);
	console.info('notification_center:', notification_center, notification_center.toString(), uneval(notification_center));

	// addObserver
	var addObserver = sel_registerName('addObserver:selector:name:object:')
	objc_msgSend(notification_center, addObserver, NoitNotifCls_instance, NoitNotifCB_selector, nsworkspace_will_launch_application_notification, NIL); // addObserver returns void
	
	shutdown = function() {
		var removeObserver = sel_registerName('removeObserver:name:object:')
		objc_msgSend(notification_center, removeObserver, NoitNotifCls_instance, nsworkspace_will_launch_application_notification, NIL); // returns void

		
		for (var i=0; i<releaseThese.length; i++) {
			objc_msgSend(releaseThese[i], release);
		}
		
		objc_disposeClassPair(NoitNotifCls_class); // return is void // must do objc_disposeClassPair AFTER release. if you do release AFTER disposeClasPair then firefox will crash
		
		objc.close();
		
		console.log('succesfully shutdown');
	}
}

try {
	main();
} catch (ex) {
	console.error('Error Occured:', ex);
} finally {
	//shutdown();
}

README

Rev1

• Untested, initial writing

Rev2

• Works, can copy paste to scratchpad
• When application launches the callback just logs something
• Commented out the shutdown in finally, so make sure to run that manually

Rev3

• Named file and gave gist a description

DEMO

This will log to the console the [NSRunningApplication bundleIdentifier] on launch of other applications, it will also forceTerminate it so you cannot start it.

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

var objc = ctypes.open(ctypes.libraryName('objc'));

// BASIC TYPES
var BOOL = ctypes.signed_char;
var CHAR = ctypes.char;
var CLASS = ctypes.voidptr_t;
var ID = ctypes.voidptr_t;
var NSNOTIFICATIONPTR = ctypes.voidptr_t;
var SEL = ctypes.voidptr_t;
var SIZE_T = ctypes.size_t
var VOID = ctypes.void_t;

// ADVANCED TYPES
var IMP_for_notif_cb = ctypes.FunctionType(ctypes.default_abi, VOID, [ID, SEL, NSNOTIFICATIONPTR]).ptr; //repalced variadic with ID as its specific to my use otherwise doing class_addMethod throws error saying expected pointer blah blah //ctypes.FunctionType(ctypes.default_abi, ID, [ID, SEL, '...']).ptr;

// CONSTANTS
var NIL = ctypes.cast(ctypes.uint64_t(0x0), ctypes.voidptr_t);

// COMMON FUNCTIONS
var class_addMethod = objc.declare('class_addMethod', ctypes.default_abi, BOOL, CLASS, SEL, IMP_for_notif_cb, CHAR.ptr);
var objc_allocateClassPair = objc.declare('objc_allocateClassPair', ctypes.default_abi, CLASS, CLASS, CHAR.ptr, SIZE_T);
var objc_disposeClassPair = objc.declare('objc_disposeClassPair', ctypes.default_abi, VOID, CLASS);
var objc_getClass = objc.declare('objc_getClass', ctypes.default_abi, ID, CHAR.ptr);
var objc_msgSend = objc.declare('objc_msgSend', ctypes.default_abi, ID, ID, SEL, '...');
var objc_registerClassPair = objc.declare('objc_registerClassPair', ctypes.default_abi, VOID, CLASS);
var sel_registerName = objc.declare('sel_registerName', ctypes.default_abi, SEL, CHAR.ptr);

// COMMON SELECTORS
var alloc = sel_registerName('alloc');
var init = sel_registerName('init');
var release = sel_registerName('release');

// my personal globals for this code
var NoitNotifCB_imp; // important to make this global otherwise on callback trigger firefox will crash, because this got GC'ed before calback triggered
var releaseThese = [];
var shutdown = function() {
    for (var i=0; i<releaseThese.length; i++) {
        objc_msgSend(releaseThese[i], release);
    }

    objc.close();

    console.log('succesfully shutdown');
}

function main() {

    // the reason i create the class first is because it starts off by running objc_allocateClassPair, if that errors, then that means theres no need to continue and do teh other stuff, that will mess up the unloadings in shutdown() and it wont shutdown properly, this was evident because i ran this code again and it couldn't allocate even after i ran shutdown(). well actually shutdown() didnt shutdown properly on consequent run because i redefined `var shutdown` before running main so duh tahts what broke it. but i would still like to place this first because then i dont unnecessarily allocate an extra NSString etc.
    // start - create class and callback
    var NSObject = objc_getClass('NSObject');
    var NoitNotifCls_class = objc_allocateClassPair(NSObject, 'NoitNotifCls', 0);
    console.info('NoitNotifCls_class:', NoitNotifCls_class, NoitNotifCls_class.toString(), uneval(NoitNotifCls_class), NoitNotifCls_class.isNull());
    if (NoitNotifCls_class.isNull()) {
        throw new Error('NoitNotifCls_class is NIL, so objc_allocateClassPair failed. objc_registerClassPair likely already ran prior to this on NoitNoitfCls_class and objc_disposeOfClassPair was not yet run on NoitNoitfCls_class'); // this happens on consequent runs after `objc_registerClassPair` is run on `NoitNotifCls_class`
    }

    var NSString = objc_getClass('NSString');
    var initWithUTF8String = sel_registerName('initWithUTF8String:');
    var userInfo = sel_registerName('userInfo');
    var objectForKey = sel_registerName('objectForKey:');
    var bundleIdentifier = sel_registerName('bundleIdentifier');
    var UTF8String = sel_registerName('UTF8String');
    var forceTerminate = sel_registerName('forceTerminate');

    var nsworkspace_application_key = objc_msgSend(objc_msgSend(NSString, alloc), initWithUTF8String, CHAR.array()('NSWorkspaceApplicationKey'));
    console.info('nsworkspace_application_key:', nsworkspace_application_key, nsworkspace_application_key.toString(), uneval(nsworkspace_application_key));
    releaseThese.push(nsworkspace_application_key);


    function NoitNotifCB_js(c_arg1__self, c_arg2__sel, objc_arg1_NSNOTIFICATIONPTR) {
        console.log('NoitNotifCB_js Triggered');
        /*
        NSRunningApplication *app = [[notification userInfo] objectForKey:NSWorkspaceApplicationKey];
        // Check if spotify is being launched
        if ([[app bundleIdentifier] isEqual:SQDSpotifyIdentifier]) {
            // And then act accordingly
            [self spotifyIsLaunching];
        }
        */
        var user_info = objc_msgSend(objc_arg1_NSNOTIFICATIONPTR, userInfo);
        var app = objc_msgSend(user_info, objectForKey, nsworkspace_application_key);

        var bundle_identifier = objc_msgSend(app, bundleIdentifier);
        //console.info('bundle_identifier:', bundle_identifier, bundle_identifier.toString(), uneval(bundle_identifier));

        // read bundle_identifier
        var tt_read = objc_msgSend(bundle_identifier, UTF8String);
        var tt_read_casted = ctypes.cast(tt_read, CHAR.ptr);
        var tt_read_jsStr = tt_read_casted.readStringReplaceMalformed();
        console.info('tt_read_jsStr:', tt_read_jsStr, tt_read_jsStr.toString(), uneval(tt_read_jsStr));

        var rez_forceTerminate = objc_msgSend(app, forceTerminate);
        console.info('forceTerminate:', forceTerminate, forceTerminate.toString(), uneval(forceTerminate));

        return NIL;
    }

    NoitNotifCB_imp = IMP_for_notif_cb(NoitNotifCB_js);

    var NoitNotifCB_selector = sel_registerName('NoitNoitfCB_objc');
    var rez_class_addMethod = class_addMethod(NoitNotifCls_class, NoitNotifCB_selector, NoitNotifCB_imp, 'v@:@'); // because return of callback is void, first argument is c_arg1__self which is `id` and c_arg2__id sel `SEL` and objc_arg1__NSNotificationPtr is `voidptr_t` // so per this page: https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html#//apple_ref/doc/uid/TP40008048-CH100 // and this chat: https://gist.github.com/Noitidart/21b202611c62d74fecd0
    console.info('rez_class_addMethod:', rez_class_addMethod, rez_class_addMethod.toString(), uneval(rez_class_addMethod));
    if (rez_class_addMethod != 1) {
        throw new Error('rez_class_addMethod is not 1, so class_addMethod failed');
    }

    objc_registerClassPair(NoitNotifCls_class); // returns void // once this line runs ,running objc_allocateClassPair on NoiTNotifCls_class will result it in being NIL

    var NoitNotifCls_instance = objc_msgSend(objc_msgSend(NoitNotifCls_class, alloc), init); // if don't do alloc init on NoitNotifCls_class then the NoitNotifCB_js never triggers
    console.info('NoitNotifCls_instance:', NoitNotifCls_instance, NoitNotifCls_instance.toString(), uneval(NoitNotifCls_instance), NoitNotifCls_instance.isNull());
    releaseThese.push(NoitNotifCls_instance);
    // end - create class and callback

    // notif_name = [[NSString initWithUTF8String:] 'NSWorkspaceWillLaunchApplicationNotification'];
    var nsworkspace_will_launch_application_notification = objc_msgSend(objc_msgSend(NSString, alloc), initWithUTF8String, CHAR.array()('NSWorkspaceWillLaunchApplicationNotification'));
    console.info('nsworkspace_will_launch_application_notification:', nsworkspace_will_launch_application_notification, nsworkspace_will_launch_application_notification.toString(), uneval(nsworkspace_will_launch_application_notification));
    releaseThese.push(nsworkspace_will_launch_application_notification);

    /*
    // default_center = [NSDistributedNotificationCenter defaultCenter];
    var NSDistributedNotificationCenter = objc_getClass('NSDistributedNotificationCenter');
    var defaultCenter = sel_registerName('defaultCenter');
    var default_center = objc_msgSend(NSDistributedNotificationCenter, defaultCenter);
    console.info('default_center:', default_center, default_center.toString(), uneval(default_center), default_center.isNull());
    */

    // shared_workspace = [NSWorkspace sharedWorkspace];
    var NSWorkspace = objc_getClass('NSWorkspace');
    var sharedWorkspace = sel_registerName('sharedWorkspace');
    var shared_workspace = objc_msgSend(NSWorkspace, sharedWorkspace);
    console.info('shared_workspace:', shared_workspace, shared_workspace.toString(), uneval(shared_workspace), shared_workspace.isNull());

    // notification_center = [[NSWorkspace sharedWorkspace] notificationCenter];
    var notificationCenter = sel_registerName('notificationCenter');
    var notification_center = objc_msgSend(shared_workspace, notificationCenter);
    console.info('notification_center:', notification_center, notification_center.toString(), uneval(notification_center));

    // addObserver
    var addObserver = sel_registerName('addObserver:selector:name:object:')
    objc_msgSend(notification_center, addObserver, NoitNotifCls_instance, NoitNotifCB_selector, nsworkspace_will_launch_application_notification, NIL); // addObserver returns void

    shutdown = function() {
        var removeObserver = sel_registerName('removeObserver:name:object:')
        objc_msgSend(notification_center, removeObserver, NoitNotifCls_instance, nsworkspace_will_launch_application_notification, NIL); // returns void


        for (var i=0; i<releaseThese.length; i++) {
            objc_msgSend(releaseThese[i], release);
        }

        objc_disposeClassPair(NoitNotifCls_class); // return is void // must do objc_disposeClassPair AFTER release. if you do release AFTER disposeClasPair then firefox will crash

        objc.close();

        console.log('succesfully shutdown');
    }
}

try {
    main();
} catch (ex) {
    console.error('Error Occured:', ex);
} finally {
    //shutdown();
}

https://github.com/DamianSullivan/TaskRail-Mac/blob/23e62e5a91c870fc26a28782026b2697ce73cf63/TaskRail/TaskRail/TRDesktopSwitcher.m#L20