Added rewrite of most of the dialog system for the new API. The Windows API is, however, getting in the way...

dialog.go

@@ -2,9 +2,40 @@
 
 package ui
 
+// Dialog is an interface adopted by all dialogs.
+type Dialog struct {
+	Response() Response	// response code from the dialog
+	Selection() interface{}	// currently nil
+}
+
+// Response denotes a response from the user to a Dialog.
+type Response uint
+const (
+	NotDone Response = iota
+	OK
+)
+
+// basic return
+type dialogret struct {
+	res	Response
+	sel	interface{}
+}
+func (d *dialogret) Response() Response { return d.res }
+func (d *dialogret) Selection() interface{} { return d.sel }	
+
 // sentinel (not nil so programmer errors don't go undetected)
 // this window is invalid and cannot be used directly
-var dialogWindow = new(Window)
+// notice the support it uses
+var dialogWindow = &Window{
+	sysData:	&sysData{
+		winhandler:	dh,
+	}
+}
+type dhandler chan *dialogret
+func (d dhandler) Event(e Event, dat interface{}) {
+	d <- dat.(*dialogret)
+}
+var dh = make(dhandler)
 
 // MsgBox displays an informational message box to the user with just an OK button.
 // primaryText should be a short string describing the message, and will be displayed with additional emphasis on platforms that support it.
@@ -13,13 +44,14 @@ var dialogWindow = new(Window)
 // On platforms that allow for the message box window to have a title, os.Args[0] is used.
 //
 // See "On Dialogs" in the package overview for behavioral information.
-func MsgBox(primaryText string, secondaryText string) {
-	<-dialogWindow.msgBox(primaryText, secondaryText)
+func MsgBox(primaryText string, secondaryText string) Response {
+	dialogWindow.msgBox(primaryText, secondaryText)
+	return (<-dh).res
 }
 
 // MsgBox is the Window method version of the package-scope function MsgBox.
 // See that function's documentation and "On Dialogs" in the package overview for more information.
-func (w *Window) MsgBox(primaryText string, secondaryText string) (done chan struct{}) {
+func (w *Window) MsgBox(primaryText string, secondaryText string) Dialog {
 	if !w.created {
 		panic("parent window passed to Window.MsgBox() before it was created")
 	}
@@ -30,15 +62,13 @@ func (w *Window) MsgBox(primaryText string, secondaryText string) (done chan str
 // Otherwise, it behaves like MsgBox.
 //
 // See "On Dialogs" in the package overview for more information.
-func MsgBoxError(primaryText string, secondaryText string) {
-	<-dialogWindow.msgBoxError(primaryText, secondaryText)
+func MsgBoxError(primaryText string, secondaryText string) Dialog {
+	dialogWindow.msgBoxError(primaryText, secondaryText)
+	return (<-dh).res
 }
 
 // MsgBoxError is the Window method version of the package-scope function MsgBoxError.
 // See that function's documentation and "On Dialogs" in the package overview for more information.
-func (w *Window) MsgBoxError(primaryText string, secondaryText string) (done chan struct{}) {
-	if !w.created {
-		panic("parent window passed to MsgBoxError() before it was created")
-	}
+func (w *Window) MsgBoxError(primaryText string, secondaryText string) Dialog {
 	return w.msgBoxError(primaryText, secondaryText)
 }

dialog_windows.go

@@ -11,7 +11,11 @@ var (
 	_messageBox = user32.NewProc("MessageBoxW")
 )
 
-func _msgBox(parent *Window, primarytext string, secondarytext string, uType uint32) (result chan int) {
+var dialogResponse = map[uintptr]Response{
+	_IDOK:		OK,
+}
+
+func _msgBox(parent *Window, primarytext string, secondarytext string, uType uint32) (result 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 != "" {
@@ -26,43 +30,28 @@ func _msgBox(parent *Window, primarytext string, secondarytext string, uType uin
 	} 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{
-				uintptr(parenthwnd),
-				utf16ToArg(ptext),
-				utf16ToArg(ptitle),
-				uintptr(uType),
-			},
-			ret: ret,
-		}
-		r := <-ret
-		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))
-		}
-		retchan <- int(r.ret)
-	}()
-	return retchan
+	r1, _, err := _messageBox.Call(
+		uintptr(parenthwnd),
+		utf16ToArg(ptext),
+		utf16ToArg(ptitle),
+		uintptr(uType))
+	if r1 == 0 { // failure
+		panic(fmt.Sprintf("error displaying message box to user: %v\nstyle: 0x%08X\ntitle: %q\ntext:\n%s", err, uType, os.Args[0], text))
+	}
+	w.sysData.winhandler.Event(Dismissed, &dialogret{
+		res:	dialogResponses[r1],
+	})
 }
 
-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 (w *Window) msgBox(primarytext string, secondarytext string) {
+	// send to uitask so the function can return immediately
+	touitask(func() {
+		_msgBox(w, primarytext, secondarytext, _MB_OK)
+	})
 }
 
-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
+func (w *Window) msgBoxError(primarytext string, secondarytext string) {
+	touitask(func() {
+		_msgBox(w, primarytext, secondarytext, _MB_OK|_MB_ICONERROR)
+	})
 }

init.go

@@ -17,13 +17,10 @@ func Go(main func()) error {
 	return ui(main)
 }
 
-// AppQuit is pulsed when the user decides to quit the program if their operating system provides a facility for quitting an entire application, rather than merely close all windows (for instance, Mac OS X via the Dock icon).
-// You should assign one of your Windows's Closing to this variable so the user choosing to quit the application is treated the same as closing that window.
-// If you do not respond to this signal, nothing will happen; regardless of whether or not you respond to this signal, the application will not quit.
-// Do not merely check this channel alone; it is not guaranteed to be pulsed on all systems or in all conditions.
-var AppQuit chan struct{}
-
-func init() {
-	// don't expose this in the documentation
-	AppQuit = newEvent()
+// This function is a simple helper functionn that basically pushes the effect of a function call for later. This allows the selected safe Window methods to be safe.
+// It's also currently used by the various dialog box functions on Windows to allow them to return instantly, rather than wait for the dialog box to finish (which both GTK+ and Mac OS X let you do). I consider this a race condition bug. TODO (also TODO document the /intended/ behavior)
+func touitask(f func()) {
+	go func() {		// to avoid locking uitask itself
+		uitask <- f
+	}()
 }

window.go

@@ -37,6 +37,7 @@ type Event int
 const (
 	Closing Event = iota			// Window close
 	Clicked					// Button click
+	Dismissed					// Dialog closed
 	CustomEvent = 5000		// very high number; higher than the package would ever need, anyway
 )