[PATCH 2/2] xdg-shell: clarify xdg_surface creation semantics regarding buffers

[Bryce Harrington]

On Wed, Dec 02, 2015 at 08:06:46PM -0500, Mike Blumenkrantz wrote:
> this change ensures that the client will set its initial state
> before performing any drawing, ensuring that there is no mismatch
> when creating a surface with a non-default state
> (eg. maximize, fullscreen, ...)
> 
> looking at the following event flows:
> 1) wl_surface.attach, wl_surface.commit, xdg_shell.get_xdg_surface
> 
> 2) wl_surface.attach, xdg_shell.get_xdg_surface, wl_surface.commit
> 
> 3) xdg_shell.get_xdg_surface, wl_surface.commit, xdg_surface.configure,
>    wl_surface.attach, wl_surface.commit
> 
> only 3) is now valid, while 1) and 2) will trigger errors as a result
> of handling buffers prior to creating the xdg surface
> 
> Reviewed-by: Jasper St. Pierre <jstpierre at mecheye.net>
> Signed-off-by: Mike Blumenkrantz <zmike at osg.samsung.com>
> Signed-off-by: Jonas Ådahl <jadahl at gmail.com>

Reviewed-by: Bryce Harrington <bryce at osg.samsung.com>

> ---
>  unstable/xdg-shell/xdg-shell-unstable-v6.xml | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/unstable/xdg-shell/xdg-shell-unstable-v6.xml b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> index 196c332..a03a615 100644
> --- a/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> +++ b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> @@ -147,14 +147,12 @@
>        them, and associate metadata like title and app id.
>  
>        The client must call wl_surface.commit on the corresponding wl_surface
> -      for the xdg_surface state to take effect. Prior to committing the new
> -      state, it can set up initial configuration, such as maximizing or setting
> -      a window geometry.
> -
> -      Even without attaching a buffer the compositor must respond to initial
> -      committed configuration, for instance sending a configure event with
> -      expected window geometry if the client maximized its surface during
> -      initialization.
> +      for the xdg_surface state to take effect.
> +
> +      Creating an xdg_surface from a wl_surface which has a buffer attached or
> +      committed is a client error, and any attempts by a client to attach or
> +      manipulate a buffer prior to the first xdg_surface.configure call must
> +      also be treated as errors.
>  
>        For a surface to be mapped by the compositor the client must have
>        committed both an xdg_surface state and a buffer.
> -- 
> 2.4.3
> 
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