Implemented the new MsgBox()/MsgBoxError() behavior on Windows.

dialog.go

@@ -19,7 +19,7 @@ var dialogWindow *Window
 // Whether or not resizing Windows will still be allowed is implementation-defined; if the implementation does allow it, resizes will still work properly.
 // Whether or not the message box stays above all other W+indows in the program is also implementation-defined.
 func MsgBox(primaryText string, secondaryText string) {
-	dialogWindow.msgBox(parent, primaryText, secondaryText)
+	<-dialogWindow.msgBox(primaryText, secondaryText)
 }
 
 // MsgBox behaves like the package-scope MsgBox function, except the message box is modal to w only.
@@ -28,24 +28,26 @@ func MsgBox(primaryText string, secondaryText string) {
 // Whether w can be resized while the message box is displayed is implementation-defined, but will work properly if allowed.
 // If w has not yet been created, MsgBox() panics.
 // If w has not been shown yet or is currently hidden, what MsgBox does is implementation-defined.
-func (w *Window) MsgBox(primaryText string, secondaryText string) {
+// 
+// On return, done will be a channel that is pulsed when the message box is dismissed.
+func (w *Window) MsgBox(primaryText string, secondaryText string) (done chan struct{}) {
 	if !w.created {
 		panic("parent window passed to Window.MsgBox() before it was created")
 	}
-	w.msgBox(primaryText, secondaryText)
+	return w.msgBox(primaryText, secondaryText)
 }
 
 // MsgBoxError displays a message box to the user with just an OK button and an icon indicating an error.
 // Otherwise, it behaves like MsgBox.
 func MsgBoxError(primaryText string, secondaryText string) {
-	dialogWindow.msgBoxError(parent, primaryText, secondaryText)
+	<-dialogWindow.msgBoxError(primaryText, secondaryText)
 }
 
 // MsgBoxError displays a message box to the user with just an OK button and an icon indicating an error.
 // Otherwise, it behaves like Window.MsgBox.
-func (w *Window) MsgBoxError(primaryText string, secondaryText string) {
+func (w *Window) MsgBoxError(primaryText string, secondaryText string) (done chan struct{}) {
 	if !w.created {
 		panic("parent window passed to MsgBoxError() before it was created")
 	}
-	w.msgBoxError(primaryText, secondaryText)
+	return w.msgBoxError(primaryText, secondaryText)
 }

dialog_windows.go

@@ -11,7 +11,7 @@ var (
 	_messageBox = user32.NewProc("MessageBoxW")
 )
 
-func _msgBox(parent *Window, primarytext string, secondarytext string, uType uint32) (result int) {
+func _msgBox(parent *Window, primarytext string, secondarytext string, uType uint32) (result chan int) {
 	// http://msdn.microsoft.com/en-us/library/windows/desktop/aa511267.aspx says "Use task dialogs whenever appropriate to achieve a consistent look and layout. Task dialogs require Windows Vista® or later, so they aren't suitable for earlier versions of Windows. If you must use a message box, separate the main instruction from the supplemental instruction with two line breaks."
 	text := primarytext
 	if secondarytext != "" {
@@ -19,15 +19,17 @@ func _msgBox(parent *Window, primarytext string, secondarytext string, uType uin
 	}
 	ptext := toUTF16(text)
 	ptitle := toUTF16(os.Args[0])
-	ret := make(chan uiret)
-	defer close(ret)
 	parenthwnd := _HWND(_NULL)
-	if parent != nil {
+	if parent != dialogWindow {
 		parenthwnd = parent.sysData.hwnd
 		uType |= _MB_APPLMODAL		// only for this window
 	} else {
 		uType |= _MB_TASKMODAL		// make modal to every window in the program (they're all windows of the uitask, which is a single thread)
 	}
+	retchan := make(chan int)
+	go func() {
+		ret := make(chan uiret)
+		defer close(ret)
 		uitask <- &uimsg{
 			call:		_messageBox,
 			p:		[]uintptr{
@@ -42,13 +44,25 @@ func _msgBox(parent *Window, primarytext string, secondarytext string, uType uin
 		if r.ret == 0 {		// failure
 			panic(fmt.Sprintf("error displaying message box to user: %v\nstyle: 0x%08X\ntitle: %q\ntext:\n%s", r.err, uType, os.Args[0], text))
 		}
-	return int(r.ret)
+		retchan <- int(r.ret)
+	}()
+	return retchan
 }
 
-func msgBox(parent *Window, primarytext string, secondarytext string) {
-	_msgBox(parent, primarytext, secondarytext, _MB_OK)
+func (w *Window) msgBox(primarytext string, secondarytext string) (done chan struct{}) {
+	done = make(chan struct{})
+	go func() {
+		<-_msgBox(w, primarytext, secondarytext, _MB_OK)
+		done <- struct{}{}
+	}()
+	return done
 }
 
-func msgBoxError(parent *Window, primarytext string, secondarytext string) {
-	_msgBox(parent, primarytext, secondarytext, _MB_OK | _MB_ICONERROR)
+func (w *Window) msgBoxError(primarytext string, secondarytext string) (done chan struct{}) {
+	done = make(chan struct{})
+	go func() {
+		<-_msgBox(w, primarytext, secondarytext, _MB_OK | _MB_ICONERROR)
+		done <- struct{}{}
+	}()
+	return done
 }

test/main.go

@@ -49,7 +49,7 @@ var macCrashTest = flag.Bool("maccrash", false, "attempt crash on Mac OS X on de
 func invalidTest(c *Combobox, l *Listbox, s *Stack, g *Grid) {
 	x := func(what string ) {
 		if j := recover(); j == nil {
-			MsgBoxError(nil, "test", fmt.Sprintf("%s: no panic", what))
+			MsgBoxError("test", fmt.Sprintf("%s: no panic", what))
 			panic("invalid test fail")
 		} else {
 			println("got", j.(error).Error())
@@ -143,7 +143,7 @@ func invalidTest(c *Combobox, l *Listbox, s *Stack, g *Grid) {
 			defer x("Area.SetSize() " + q.msg); a.SetSize(q.x, q.y); panic(nil)
 		}()
 	}
-	MsgBox(nil, "test", "all working as intended")
+	MsgBox("test", "all working as intended")
 }
 
 var invalidBefore = flag.Bool("invalid", false, "run invalid test before opening window")
@@ -226,7 +226,7 @@ func areaTest() {
 			if err != nil { println(err); continue }
 			a.SetSize(width, height)
 		case <-modaltest.Clicked:
-			MsgBox(nil, "Modal Test", "")
+			MsgBox("Modal Test", "")
 		}
 	}
 }
@@ -260,6 +260,8 @@ func areaboundsTest() {
 	<-w.Closing
 }
 
+var dialogTest = flag.Bool("dialog", false, "add Window.MsgBox() channel test window")
+
 func myMain() {
 	if *doArea {
 		areaTest()
@@ -284,6 +286,9 @@ func myMain() {
 	cb2 := NewCombobox("You can't edit me!", "No you can't!", "No you won't!")
 	e := NewLineEdit("Enter text here too")
 	l := NewLabel("This is a label")
+	resetl := func() {
+		l.SetText("This is a label")
+	}
 	b3 := NewButton("List Info")
 	s3 := NewHorizontalStack(l, b3)
 	s3.SetStretchy(0)
@@ -330,6 +335,17 @@ func myMain() {
 
 	ticker := time.Tick(time.Second)
 
+	dialog_bMsgBox := NewButton("MsgBox()")
+	dialog_bMsgBoxError := NewButton("MsgBoxError()")
+	dialog_win := NewWindow("Dialogs", 200, 200)
+	if *dialogTest {
+		dialog_win.Open(NewVerticalStack(
+			dialog_bMsgBox,
+			dialog_bMsgBoxError))
+	}
+
+	var dialog_sret chan struct{} = nil
+
 mainloop:
 	for {
 		select {
@@ -368,7 +384,7 @@ _=curtime
 			if c.Checked() {
 				f = MsgBoxError
 			}
-			f(nil, "List Info",
+			f("List Info",
 				fmt.Sprintf("cb1: %d %q (len %d)\ncb2: %d %q (len %d)\nlb1: %d %q (len %d)\nlb2: %d %q (len %d)",
 				cb1.SelectedIndex(), cb1.Selection(), cb1.Len(),
 				cb2.SelectedIndex(), cb2.Selection(), cb2.Len(),
@@ -393,8 +409,18 @@ _=curtime
 		case <-invalidButton.Clicked:
 			invalidTest(cb1, lb1, nil, nil)
 		case <-bmsg.Clicked:
-			MsgBox(nil, "Title Only, no parent", "")
-			MsgBox(w, "Title and Text", "parent")
+			MsgBox("Title Only, no parent", "")
+			MsgBox("Title and Text", "parent")
+		// dialogs
+		case <-dialog_bMsgBox.Clicked:
+			dialog_sret = dialog_win.MsgBox("Message Box", "Dismiss")
+			l.SetText("DIALOG")
+		case <-dialog_bMsgBoxError.Clicked:
+			dialog_sret = dialog_win.MsgBoxError("Message Box", "Dismiss")
+			l.SetText("DIALOG")
+		case <-dialog_sret:
+			dialog_sret = nil
+			resetl()
 		}
 	}
 	w.Hide()