exiting after CreateRootWindow() but before message_loop->Ru

[michaeladamkatz]

In my Windows CEF application I call

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context->GetRootWindowManager()->CreateRootWindow( window_config );

and then I do some application specific checks for which I need the window handle to already exist. Then depending on the results of those application specific checks I either call

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message_loop->Run();

or I just exit the app.

When I just exit the app I'm getting some assertions, specifically that RootWindowManager's root_windows_ is not empty, or that RootWindowWin's browser_destroyed_ or window_destroyed_ are false.

It appears that if I could call

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BrowserWindow::OnBrowserClosed(CefRefPtr<CefBrowser> browser)

it would do the right things to clean up all three of those variables. But I don't know how to access the current BrowserWindow (the active ClientHandler::Delegate?) to call OnBrowserClosed(). (And is this even the best way to handle this situation?)

I understand it might be better to only call CreateRootWindow() if I know I'm then going to call message_loop->Run(). But as I say, it would be most convenient for my app to call CreateRootWindow() and then possibly bail out.

[ndesktop]

The cleanup/shutdown process is not easy. Basically, you have to track the callbacks (On...Destroyed, On...Closed) and get out when the refcount drops to zero.
Here is my shutdown pseudocode (ClientHandler is the ... CEF client handler implementation, MainWindow is the main/root window; browser is CefRefPtr<CefBrowser>):

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ClientHandler::OnBeforeClose(browser)
  browsers_count--;
  _NotifyBrowserClosed(browser) - ensure TID_UI
    main window (root) => OnBrowserClosed

MainWindow::OnBrowserClosed(browser)
  browsers_destroyed = handler->browsers_count is 0
  if browsers_destroyed
    DestroyWindow(MainWindow.hWnd)
  if browsers_destroyed AND main_window_destroyed
    CefDoMessageLoopWork();
    CefQuitMessageLoop();

MainWindow::OnNCDestroy
  main_window_destroyed = true
  ...

So is short (in reality is a little bit more complicated, but let's keep the main idea simple):
1. ClientHandler notifies with OnBeforeClose for all CefBrowser (browser_count drops to zero)
2. MainWindow gets notified on browser destruction until reaches 0
3. MainWindow is destroyed (== WM_NCDESTROY handled by MainWindow)
4. when no more browsers exists and the main window has been destroyed, call CefDoMessageLoopWork one more time and finally CefQuitMessageLoop.

[magreenblatt]

I understand it might be better to only call CreateRootWindow() if I know I'm then going to call message_loop->Run(). But as I say, it would be most convenient for my app to call CreateRootWindow() and then possibly bail out.

If your application is going to bail early you should do so before calling CreateRootWindow (or even before CefInitialize).

[magreenblatt]

4. when no more browsers exists and the main window has been destroyed, call CefDoMessageLoopWork one more time and finally CefQuitMessageLoop.

CefQuitMessageLoop is used with CefRunMessageLoop, not CefDoMessageLoopWork. See https://bitbucket.org/chromiumembedded/ ... ntegration

[ndesktop]

I was thinking to call once (not one more time as I wrote) CefDoMessageLoopWork in order to consume pending messages, if any.
I am using CefRunMessageLoop/CefQuitMessageLoop. Using CefDoMessageLoopWork (once, just before CefQuitMessageLoop) is a programming error then?

[magreenblatt]

I was thinking to call once (not one more time as I wrote) CefDoMessageLoopWork in order to consume pending messages, if any.
I am using CefRunMessageLoop/CefQuitMessageLoop. Using CefDoMessageLoopWork (once, just before CefQuitMessageLoop) is a programming error then?

It's not necessary but probably not harmful.