Re: Reverting to non-async file chooser

["Matthias Clasen" <matthias clasen gmail com>]

On 8/17/06, Federico Mena Quintero <federico ximian com> wrote:

> OK, so here's the plan of action.
>
> Semantics of callbacks and cancellation
> =======================================
>
> - You need to hit the idle loop for your callback to be called, just
>   like in GnomeVFS.
>
> - You do not need to ever ref/unref async handles; they are opaque
>   cookies.
>
> - Once you call gtk_file_system_cancel_operation(), you can assume
>   that the callback corresponding to the handle will NOT be called.
>   Therefore, the caller must free the stuff in the callback's closure
>   as appropriate.
>
>   Rationale:  the idle loop may be far away in time.  By that time, it
>   is very likely that the closure of the callback is no longer valid.
>   So, we want to get rid of it as soon as possible.
>
>   Caveat:  gnome-vfs does not let you cancel the operation of mounting
>   a drive or volume.  So if you cancel the handle from
>   gtk_file_system_volume_mount(), your callback will not be called,
>   but the volume *will* be mounted (unless an error occurs during
>   mounting, of course).
>
>   Notes:  The current scheme (callbacks get called even when
>   cancelled; caller must unref the handle in the callback) doesn't
>   make sense.  Callbacks test if the handle being passed is the same
>   that got remembered; this causes leaks if an old handle had been
>   canceled but the idle loop did not run yet.
>
> Plan of action
> ==============
>
> 1. Add assertions in GtkFileSystemGnomeVFS so that no async handles
>    are outstanding when the file_system's finalizer gets run.  DONE.
>
> 2. Add assertions to GtkFileSystemUnix in a similar fashion.
>
> 3. Write a test suite for the async operations of GtkFileSystem,
>    similar in spirit to gnome-vfs/test/test-async-cancel.c.  IN PROGRESS.
>
>    [I think op_data is being leaked quite often in
>    gtkfilesystemgnomevfs.c, but haven't proved it yet.]
>
> 4. Run that test suite against GtkFileSystemGnomeVFS.
>
> 5. Run that test suite against GtkFileSystemUnix.
>
> 6. Fix gtkfilechooser*.c to handle the new semantics for async
>    handles.  See the patches in these bugs:
>
>       http://bugzilla.gnome.org/show_bug.cgi?id=349998
>       http://bugzilla.gnome.org/show_bug.cgi?id=348113
>
> 7. Ensure that autotestfilechooser passes all tests.  This will take
>    care of the big overwrite-confirmation bug:
>
>       http://bugzilla.gnome.org/show_bug.cgi?id=347883
>
> 8. ???
>
> 9. Profit!!!
>
> I'm getting kind of nervous that RC1 for GNOME 2.16 is a few days away.
> Help is much appreciated to finish the tasks above that are not done.

Thanks for taking the initiative and coming up with this plan. Once I have
2.10.2 out, I'll see if I can help.

Matthias