[PATCH weston 3/3] compositor: don't map surfaces without a buffer

[Derek Foreman]

On 03/02/17 09:10 AM, Emilio Pozuelo Monfort wrote:
> We were calling weston_surface::committed on surfaces with
> no buffer attached. Stop doing that, since surface::committed
> will map the surfaces and put them in a visible layer. That may
> not be a problem for a single surface as it wouldn't be visible
> anyway because it's got no contents, but it is a problem if the
> surface has subsurfaces.
>
> This fixes the subsurface_mapped test, so mark it as expected
> to succeed.
>
> https://bugs.freedesktop.org/show_bug.cgi?id=94735
>
> Signed-off-by: Emilio Pozuelo Monfort <emilio.pozuelo at collabora.co.uk>
> ---
>  libweston/compositor.c       | 10 +++++++++-
>  tests/subsurface-shot-test.c |  2 +-
>  2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/libweston/compositor.c b/libweston/compositor.c
> index 81392063..8a018897 100644
> --- a/libweston/compositor.c
> +++ b/libweston/compositor.c
> @@ -1589,6 +1589,12 @@ weston_surface_is_mapped(struct weston_surface *surface)
>  	return surface->is_mapped;
>  }
>
> +static bool
> +weston_surface_has_content(struct weston_surface *surface)
> +{
> +	return surface->width > 0 && surface->height > 0;

Are these going to be 0 if a NULL buffer is attached to an existing surface?

A quick read has me thinking width_from_buffer and height_from_buffer 
are reset on a NULL attach, but width and height only get updated on 
commit - so depending on when this function is called it might not 
return the expected result.

If that's the intended behaviour, perhaps a comment to avoid misuse in 
the future...

> +}
> +
>  static void
>  surface_set_size(struct weston_surface *surface, int32_t width, int32_t height)
>  {
> @@ -2928,7 +2934,9 @@ weston_surface_commit_state(struct weston_surface *surface,
>
>  	if (state->newly_attached || state->buffer_viewport.changed) {
>  		weston_surface_update_size(surface);
> -		if (surface->committed)
> +		if (surface->committed &&
> +		    (state->newly_attached &&
> +		     weston_surface_has_content(surface)))
>  			surface->committed(surface, state->sx, state->sy);
>  	}
>
> diff --git a/tests/subsurface-shot-test.c b/tests/subsurface-shot-test.c
> index e7da1e0e..275d4726 100644
> --- a/tests/subsurface-shot-test.c
> +++ b/tests/subsurface-shot-test.c
> @@ -261,7 +261,7 @@ TEST(subsurface_z_order)
>  			buffer_destroy(bufs[i]);
>  }
>
> -FAIL_TEST(subsurface_mapped)
> +TEST(subsurface_mapped)
>  {
>  	const char *test_name = get_test_name();
>  	struct client *client;

Why not re-order these commits so the subsurface test is introduced in a 
passing state?

Thanks,
Derek