[PATCH weston] xwayland: set surface_id to 0 when client resource is found

[Boyan Ding]

Only when reading through mails today did I find I had duplicated
efforts [1], sorry.

This patch is
Reviewed-by: Boyan Ding <stu_dby at 126.com>

[1]
http://lists.freedesktop.org/archives/wayland-devel/2014-July/015943.html

On Wed, 2014-07-02 at 15:00 -0700, Tyler Veness wrote:
> When Xwayland requests that a wl_surface be created and the X event is
> handled before the wayland requests, a surface ID is stored to
> window->surface_id and the window is added to the unpaired window list. When
> weston_wm_create_surface is called, the window is removed from the list and
> window->surface_id is set to zero. If window->surface_id is not zero when
> weston_wm_window_destroy is called, the window is assumed to be in the
> unpaired window list and wl_list_remove is called. If
> weston_wm_window_handle_surface_id is called and the surface has already
> been created, the window is not added to the unpaired window list, but
> window->surface_id isn't set to zero. When the window is destroyed, removing
> the window from the list is attempted anyway and a crash occurs.
> 
> This patch stores the surface ID in a temporary variable and only assigns it
> to window->surface_id when the window is added to the unpaired window list.
> Otherwise window->surface_id is set to zero to maintain its use as a flag
> variable.
> 
> Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=80273
> Signed-off-by: Tyler Veness <calcmogul at gmail.com>
> ---
>  xwayland/window-manager.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/xwayland/window-manager.c b/xwayland/window-manager.c
> index 2fb65b1..4c98baf 100644
> --- a/xwayland/window-manager.c
> +++ b/xwayland/window-manager.c
> @@ -1374,14 +1374,17 @@ weston_wm_window_handle_surface_id(struct weston_wm_window *window,
>  	 * hasn't been created yet.  In that case put the window on
>  	 * the unpaired window list and continue when the surface gets
>  	 * created. */
> -	window->surface_id = client_message->data.data32[0];
> -	resource = wl_client_get_object(wm->server->client,
> -					window->surface_id);
> -	if (resource)
> +	uint32_t surface = client_message->data.data32[0];
> +	resource = wl_client_get_object(wm->server->client, surface);
> +	if (resource) {
> +		window->surface_id = 0;
>  		xserver_map_shell_surface(window,
>  					  wl_resource_get_user_data(resource));
> -	else
> +	}
> +	else {
> +		window->surface_id = surface;
>  		wl_list_insert(&wm->unpaired_window_list, &window->link);
> +	}
>  }
>  
>  static void