Binding funtions for use in window.webkit object

[ukane-philemon]

Hi, @progrium. Nice work so far.

I'm trying to setup webkit functions to use on the FE but I keep getting a panic when the webkit function is executed. I dunno if I missed anything. Any help/comment is appreciated. Thanks in advance.

My code:

        init() {
        ....
        // Set the user controller. This object coordinates interactions the app’s
	// native code and the webpage’s scripts and other content. See:
	// https://developer.apple.com/documentation/webkit/wkwebviewconfiguration/1395668-usercontentcontroller?language=objc.
	webviewConfig.Set("userContentController:", objc.Get("WKUserContentController").Alloc().Init())
        ....
        }
        
        func bind() {
        fnClass := registerNewClass("notificationHandler")
	// The provided function must implement the WKScriptMessageHandler protocol.
	// See:
	// https://developer.apple.com/documentation/webkit/wkscriptmessagehandler?language=objc
	fnClass.AddMethod("userContentController:didReceiveScriptMessage:", func(_ objc.Object, ct objc.Object /* WKUserContentController */, msg objc.Object, wv objc.Object /* webview */) {
		// Arguments must be provided as an array(NSSingleObjectArrayI or NSArrayI).
		msgBody := msg.Get("body")
		defer msgBody.Release()

		msgClass := msgBody.Class().String()
		msgString := msgBody.String()
		if !strings.Contains(msgClass, "Array") {
			log.Errorf("Received unexpected argument type %s (content: %s)", msgClass, msgString)
			return // do nothing
		}

		args := parseJSCallbackArgs(msgBody)
		if args == nil {
			log.Errorf("Received unexpected argument type %s (content: %s)", msgClass, msgString)
			return // do nothing
		}

		fnArgsCount := args.Count() - 1 // fnName argument
		var fnArgs []objc.Object
		if fnArgsCount > 0 {
			for i := 1; i < int(fnArgsCount); i++ {
				fnArgs = append(fnArgs, args.ObjectAtIndex(uint64(i)))
			}
		}

		fnName := args.ObjectAtIndex(0).String()
		switch fnName {
		case "sendOSNotification":
			sendDesktopNotificationJSCallback(fnArgs)
		}
	})

	// The name of this function in the browser window is
	// window.webkit.messageHandlers.<name>.postMessage(<messageBody>), where
	// <name> corresponds to the value of this parameter. For example, if you
	// specify the string openURL, the user content controller defines the
	// window.webkit.messageHandlers.openURL.postMessage() function in
	// JavaScript. See:
	// https://developer.apple.com/documentation/webkit/wkusercontentcontroller/1537172-addscriptmessagehandler?language=objc
	webviewConfig.Get("userContentController").Send("addScriptMessageHandler:name:", objc.Get("notificationHandler").Alloc().Init(), mdCore.String("notificationHandler"))
	}

      func sendDesktopNotificationJSCallback(args []objc.Object) {
	const expectedArgs = 2
	const defaultTitle = "Notification"

	if len(args) == 0 {
		return
	}

	title := args[0]
	defer title.Release()
	emptyTitle := title.Class().String() == nullType
	if len(args) == 1 && !emptyTitle {
		sendDesktopNotification(defaultTitle, title.String())
		return
	}

	body := args[1]
	defer body.Release()
	emptyBody := body.Class().String() == nullType
	switch {
	case emptyBody && !emptyTitle:
		sendDesktopNotification(defaultTitle, title.String())
	case emptyTitle && !emptyBody:
		sendDesktopNotification(defaultTitle, body.String())
	}
     }

Panic log:

fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x7ff8142e9a4a]

runtime stack:
runtime.throw({0x101ac03d4?, 0x2bfefd2a0?})
        /usr/local/go/src/runtime/panic.go:1047 +0x5d fp=0x7ff7bfefd258 sp=0x7ff7bfefd228 pc=0x10003c45d
runtime.sigpanic()
        /usr/local/go/src/runtime/signal_unix.go:825 +0x3e9 fp=0x7ff7bfefd2b8 sp=0x7ff7bfefd258 pc=0x1000536e9

goroutine 1 [syscall, locked to thread]:
runtime.cgocall(0x1014ac340, 0xc00020bb98)
        /usr/local/go/src/runtime/cgocall.go:157 +0x5c fp=0xc00020bb70 sp=0xc00020bb38 pc=0x1000081dc
github.com/progrium/macdriver/cocoa._Cfunc_NSApplication_inst_run(0x103c21570)
        _cgo_gotypes.go:457 +0x45 fp=0xc00020bb98 sp=0xc00020bb70 pc=0x101364c25
github.com/progrium/macdriver/cocoa.gen_NSApplication.Run.func1({{0x10255ca08?, 0xc00032b800?}})
        /Users/<name>/go/pkg/mod/github.com/progrium/macdriver@v0.4.0/cocoa/cocoa_objc.gen.go:9572 +0x4d fp=0xc00020bbd0 sp=0xc00020bb98 pc=0x10138c8cd
github.com/progrium/macdriver/cocoa.gen_NSApplication.Run({{0x10255ca08?, 0xc00032b800?}})
        /Users/<name>/go/pkg/mod/github.com/progrium/macdriver@v0.4.0/cocoa/cocoa_objc.gen.go:9572 +0x25 fp=0xc00020bbf0 sp=0xc00020bbd0 pc=0x10138c845
main.mainCore()

[ukane-philemon]

Kinda resolved: See: decred/dcrdex@e04d503#diff-0602b2692abb55190ccaeaf47731f989d943bf32a8a5ad48b98e8f7c91064cd7