[PATCH 1/5] compositor-drm: Use non-cast functions to retrieve backend and output objects

[Pekka Paalanen]

On Mon,  1 Aug 2016 19:17:53 +0200
Armin Krezović <krezovic.armin at gmail.com> wrote:

> This uses container_of instead of explicit cast to retrieve
> backend and output objects from generic weston_backend and
> weston_output pointers.
> 
> Signed-off-by: Armin Krezović <krezovic.armin at gmail.com>
> ---
>  libweston/compositor-drm.c | 69 +++++++++++++++++++++++++++-------------------
>  1 file changed, 40 insertions(+), 29 deletions(-)
> 
> diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
> index 737fa9d..fb9c623 100644
> --- a/libweston/compositor-drm.c
> +++ b/libweston/compositor-drm.c
> @@ -224,6 +224,18 @@ static struct gl_renderer_interface *gl_renderer;
>  
>  static const char default_seat[] = "seat0";
>  
> +static inline struct drm_output *
> +to_drm_output(struct weston_output *base)
> +{
> +	return container_of(base, struct drm_output, base);
> +}
> +
> +static inline struct drm_backend *
> +to_drm_backend(struct weston_compositor *base)
> +{
> +	return container_of(base->backend, struct drm_backend, base);
> +}
> +
>  static void
>  drm_output_set_cursor(struct drm_output *output);
>  
> @@ -234,7 +246,7 @@ static int
>  drm_sprite_crtc_supported(struct drm_output *output, uint32_t supported)
>  {
>  	struct weston_compositor *ec = output->base.compositor;
> -	struct drm_backend *b =(struct drm_backend *)ec->backend;
> +	struct drm_backend *b = to_drm_backend(ec);
>  	int crtc;
>  
>  	for (crtc = 0; crtc < b->num_crtcs; crtc++) {
> @@ -505,8 +517,7 @@ static struct weston_plane *
>  drm_output_prepare_scanout_view(struct drm_output *output,
>  				struct weston_view *ev)
>  {
> -	struct drm_backend *b =
> -		(struct drm_backend *)output->base.compositor->backend;
> +	struct drm_backend *b = to_drm_backend(output->base.compositor);
>  	struct weston_buffer *buffer = ev->surface->buffer_ref.buffer;
>  	struct weston_buffer_viewport *viewport = &ev->surface->buffer_viewport;
>  	struct gbm_bo *bo;
> @@ -552,7 +563,7 @@ static void
>  drm_output_render_gl(struct drm_output *output, pixman_region32_t *damage)
>  {
>  	struct drm_backend *b =
> -		(struct drm_backend *)output->base.compositor->backend;
> +		to_drm_backend(output->base.compositor);

Hi Armin,

this and several other cases below would probably fit on one line now.
But the issue I didn't just land this patch is...

>  	struct gbm_bo *bo;
>  
>  	output->base.compositor->renderer->repaint_output(&output->base,
> @@ -602,7 +613,7 @@ static void
>  drm_output_render(struct drm_output *output, pixman_region32_t *damage)
>  {
>  	struct weston_compositor *c = output->base.compositor;
> -	struct drm_backend *b = (struct drm_backend *)c->backend;
> +	struct drm_backend *b = to_drm_backend(c);
>  
>  	if (b->use_pixman)
>  		drm_output_render_pixman(output, damage);
> @@ -618,9 +629,9 @@ drm_output_set_gamma(struct weston_output *output_base,
>  		     uint16_t size, uint16_t *r, uint16_t *g, uint16_t *b)
>  {
>  	int rc;
> -	struct drm_output *output = (struct drm_output *) output_base;
> +	struct drm_output *output = to_drm_output(output_base);
>  	struct drm_backend *backend =
> -		(struct drm_backend *) output->base.compositor->backend;
> +		to_drm_backend(output->base.compositor);
>  
>  	/* check */
>  	if (output_base->gamma_size != size)
> @@ -664,9 +675,9 @@ static int
>  drm_output_repaint(struct weston_output *output_base,
>  		   pixman_region32_t *damage)
>  {
> -	struct drm_output *output = (struct drm_output *) output_base;
> +	struct drm_output *output = to_drm_output(output_base);
>  	struct drm_backend *backend =
> -		(struct drm_backend *)output->base.compositor->backend;
> +		to_drm_backend(output->base.compositor);
>  	struct drm_sprite *s;
>  	struct drm_mode *mode;
>  	int ret = 0;
> @@ -763,9 +774,9 @@ err_pageflip:
>  static void
>  drm_output_start_repaint_loop(struct weston_output *output_base)
>  {
> -	struct drm_output *output = (struct drm_output *) output_base;
> -	struct drm_backend *backend = (struct drm_backend *)
> -		output_base->compositor->backend;
> +	struct drm_output *output = to_drm_output(output_base);
> +	struct drm_backend *backend =
> +		to_drm_backend(output_base->compositor);
>  	uint32_t fb_id;
>  	struct timespec ts, tnow;
>  	struct timespec vbl2now;
> @@ -873,7 +884,7 @@ static void
>  page_flip_handler(int fd, unsigned int frame,
>  		  unsigned int sec, unsigned int usec, void *data)
>  {
> -	struct drm_output *output = (struct drm_output *) data;
> +	struct drm_output *output = to_drm_output(data);

...the data argument is already a struct drm_output *. It comes from
the drmModePageFlip() call which is implemented in libdrm.

The only thing to do here would be to just drop the cast, since void*
casts automatically.


Otherwise the whole patch looks good.


Thanks,
pq
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