Günther,
> I'm trying to figure out how the Dolphin Views receive event messages
> from windows.
You might find it helpful to read the MS description of the fundamentals of the
Windows message system (you'll have to reassemble the URL)
http://msdn.microsoft.com/library/en-us/winui/winui/windowsuserinterface/windowing/messagesandmessagequeues/
aboutmessagesandmessagequeues.asp
When you read that bear in mind that, Dolphin is from Windows' POV, a
single-threaded application, meaning that it has a single message loop that
handles all its windows. The main message loop itself is provided by the
current InputState, and each message is handled by InputState>>pumpMessage:.
That finds the corresponding window (probably a View instance) in its internal
map of handles->Views, and it sends #preTranslateMessage: to that. If that
doesn't consume the message it then it tries the window's parent, and so on.
In none of them consume it, then the message is passed back to Windows for
"dispatching" (as described in the above link), which means that Windows will
directly call a handler function that it knows is associated with the
corresponding window.
As far as I know, all Dolphin windows use the same function, which is actually
part of the VM (see VMLibrary>>getWndProc) itself. That function apparently
invokes the #wndProc:message:wParam:lParam:cookie: method of the current
InputState. So once again the InputState looks up the message in its map of
handles->View instances, and this time sends #dispatchMessage:wparam:lParam: to
the discovered View.
From their the default handling is to look up the message in the "MessageMap"
to find a corresponding selector, and the View instance then #perform:s that
selector, so you then end up in one of the hundreds of little methods in
category 'event handling-win32'. There -- finally -- the event is translated
into MVP terms and ordinary Dolphin GUI code takes over.
So, all in all, the two places where Windows events are passed to View
instances are the #preTranslateMessage: and #dispatchMessage:wparam:lParam:
methods. In both cases they are sent directly to the instance itself.
(BTW, I didn't understand much, if any, of this before this morning; I've just
spent a happy hour tracing through what happens. There were other things that
I'd been planning to do with the time, but I had fun anyway. Thanks! ;-)
-- chris
Locked
