[Spice-devel] [spice-gtk] gtk-session: do not request guest's clipboard data unnecessarily

[Jakub Janku]

Hi,


On Wed, Jan 2, 2019, 5:31 PM Victor Toso <victortoso at redhat.com wrote:

> Hi,
>
> Thanks for taking a look!
>
> On Sun, Dec 30, 2018 at 10:23:02PM +0100, Jakub Janku wrote:
> > Hi,
> >
> > On Wed, Dec 19, 2018 at 3:30 PM Victor Toso <victortoso at redhat.com>
> wrote:
> > >
> > > From: Victor Toso <me at victortoso.com>
> > >
> > > If SpiceGtkSession is holding the keyboard, that's huge indication
> > > that we should not be requesting clipboard data yet. The proper time
> > > to request it is when another application in the client machine is
> > > asking for it, which means the user would switch to another
> > > application to paste the guest's clipboard data.
> > >
>
> > I'm having a rather hard time understanding this commit message.
> > I read it the following way:
> > "spice-gtk should not request clipboard data from vdagent, while
> > spice-gtk holds the keyboard focus"
> > However, what the patch actually does is that it makes sure that
> > spice-gtk doesn't send clipboard grab to vdagent, while spice-gtk
> > holds the keyboard focus.
> >
> > These 2 things seem rather unrelated. What am I missing?
>
> Client request for grab will make agent to look into clipboard
> data in the guest which would lead to VD_AGENT_CLIPBOARD_REQUEST
> being sent from agent to client.
>

Exactly! So it's the agent requesting the CLIENT's data. But in the commit
message, you state "do not request GUEST's clipboard data unnecessarily".
Or isn't it?

>
> I tried to avoid the grab first; I can also delay the clipboard
> data request to a later time (like when the keyboard is out of
> focus, as I suggested in the patch and explained below)
>
> > > This is default behavior over wayland.
> >
> > I can confirm that on Wayland, this patch breaks copy&paste
> > from client to guest.
> > According to the Wayland docs, the windows should receive the
> > owner-change event before the focus-in event (
> >
> https://wayland.freedesktop.org/docs/html/ch04.html#sect-Protocol-data-sharing
> > have a look at Data devices.Selection: "This event is also generated
> > on a client immediately before it receives keyboard focus.").
> > But as it turns out, gtk+ delays the event so that the focus-in event
> > comes first (
> https://gitlab.gnome.org/GNOME/gtk/blob/gtk-3-24/gdk/wayland/gdkdevice-wayland.c
> > check out the keyboard_handle_enter() ).
> > So this patch will unfortunately need some changes in order to
> > work on Wayland.
>
> Yep!
>
> > > Related: https://gitlab.freedesktop.org/spice/win32/vd_agent/issues/6
> > > Related: https://gitlab.freedesktop.org/spice/linux/vd_agent/issues/9
> > > Related: https://bugzilla.redhat.com/show_bug.cgi?id=1594876
> >
> > Could you please elaborate a bit more on why this patch solves these
> issues?
>
> I can reproduce the client requesting guest's clipboard data on
> X11/KDE multiple times while the user is just copy-paste between
> applications in the guest. The idea of this patch was to avoid
> those requests till the keyboard focus is lost, which means that
> user is trying to paste guest's clipboard data into another
> application in the client's OS.
>
> Let me know if it isn't clear!
>

Makes sense to me to try to avoid such requests. But why are those requests
causing the issues described?

>
> > Cheers,
> > Jakub
>
> Thanks again,
> Victor
>
>
> > >
> > > Signed-off-by: Victor Toso <victortoso at redhat.com>
> > > Tested-by: James Harvey @jamespharvey20
> > > ---
> > >  src/spice-gtk-session.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/src/spice-gtk-session.c b/src/spice-gtk-session.c
> > > index 1ccae07..0d3438c 100644
> > > --- a/src/spice-gtk-session.c
> > > +++ b/src/spice-gtk-session.c
> > > @@ -645,9 +645,11 @@ static void clipboard_owner_change(GtkClipboard
>       *clipboard,
> > >          if (gtk_clipboard_get_owner(clipboard) == G_OBJECT(self))
> > >              break;
> > >
> > > +
> > >          s->clipboard_by_guest[selection] = FALSE;
> > >          s->clip_hasdata[selection] = TRUE;
> > > -        if (s->auto_clipboard_enable && !read_only(self))
> > > +        if (s->auto_clipboard_enable && !read_only(self) &&
> > > +            !spice_gtk_session_get_keyboard_has_focus(self))
> > >              gtk_clipboard_request_targets(clipboard,
> clipboard_get_targets,
> > >                                            get_weak_ref(self));
> > >          break;
> > > --
> > > 2.19.2
> > >
> > > _______________________________________________
> > > Spice-devel mailing list
> > > Spice-devel at lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/spice-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/spice-devel/attachments/20190103/f2cc26f9/attachment.html>