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

[Jakub Janku]

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?

> 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.
>
> 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?

Cheers,
Jakub
>
> 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
>
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