On Fri, Nov 23, 2012 at 03:56:51PM +0200, Pekka Paalanen wrote:
> The wl_buffer reference counting API has been inconsistent. You would
> manually increment the refcount and register a destroy listener, as
> opposed to calling weston_buffer_post_release(), which internally
> decremented the refcount, and then removing a list item.
>
> Replace both cases with a single function:
> weston_buffer_reference(wl_buffer **ref, wl_buffer *buffer, listener)
>
> Buffer is assigned to *ref, while taking care of all the refcounting and
> release posting. You take a reference by passing a non-NULL buffer, and
> release a reference by passing NULL as buffer. Registering and
> de-registering the destroy listener is included.
>
> This is inspired by the pipe_resource_reference() of Mesa.
>
> Additionally, when a surface gets destroyed, the associated wl_buffer
> will send a release event. Usually the buffer is already destroyed on
> client side, so the event will be discarded by libwayland-client.
>
> Signed-off-by: Pekka Paalanen <[email protected]>
I think this is fine, but can we make it a struct
weston_buffer_reference instead, that includes the struct wl_listener
and buffer pointer? All users just set up a listener that NULLs the
buffer pointers so we should pull that logic into the reference and
reduce the required boilerplate code.
Kristian
> ---
> src/compositor.c | 31 +++++++++++++++++++++----------
> src/compositor.h | 4 ++++
> 2 files changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/src/compositor.c b/src/compositor.c
> index 3399ad4..c1fc287 100644
> --- a/src/compositor.c
> +++ b/src/compositor.c
> @@ -779,8 +779,8 @@ destroy_surface(struct wl_resource *resource)
> if (surface->pending.buffer)
> wl_list_remove(&surface->pending.buffer_destroy_listener.link);
>
> - if (surface->buffer)
> - wl_list_remove(&surface->buffer_destroy_listener.link);
> + weston_buffer_reference(&surface->buffer, NULL,
> + &surface->buffer_destroy_listener);
>
> pixman_region32_fini(&surface->texture_damage);
> compositor->renderer->destroy_surface(surface);
> @@ -808,27 +808,36 @@ weston_surface_destroy(struct weston_surface *surface)
> destroy_surface(&surface->surface.resource);
> }
>
> -static void
> -weston_surface_attach(struct weston_surface *surface, struct wl_buffer
> *buffer)
> +WL_EXPORT void
> +weston_buffer_reference(struct wl_buffer **ref, struct wl_buffer *buffer,
> + struct wl_listener *buffer_destroy_listener)
> {
> - if (surface->buffer && buffer != surface->buffer) {
> - weston_buffer_post_release(surface->buffer);
> - wl_list_remove(&surface->buffer_destroy_listener.link);
> + if (*ref && buffer != *ref) {
> + weston_buffer_post_release(*ref);
> + wl_list_remove(&buffer_destroy_listener->link);
> }
>
> - if (buffer && buffer != surface->buffer) {
> + if (buffer && buffer != *ref) {
> buffer->busy_count++;
> wl_signal_add(&buffer->resource.destroy_signal,
> - &surface->buffer_destroy_listener);
> + buffer_destroy_listener);
> }
>
> + *ref = buffer;
> +}
> +
> +static void
> +weston_surface_attach(struct weston_surface *surface, struct wl_buffer
> *buffer)
> +{
> + weston_buffer_reference(&surface->buffer, buffer,
> + &surface->buffer_destroy_listener);
> +
> if (!buffer) {
> if (weston_surface_is_mapped(surface))
> weston_surface_unmap(surface);
> }
>
> surface->compositor->renderer->attach(surface, buffer);
> - surface->buffer = buffer;
> }
>
> WL_EXPORT void
> @@ -1147,6 +1156,8 @@ surface_attach(struct wl_client *client,
> if (buffer_resource)
> buffer = buffer_resource->data;
>
> + /* Attach, attach, without commit in between does not send
> + * wl_buffer.release. */
> if (surface->pending.buffer)
> wl_list_remove(&surface->pending.buffer_destroy_listener.link);
>
> diff --git a/src/compositor.h b/src/compositor.h
> index e770664..9809238 100644
> --- a/src/compositor.h
> +++ b/src/compositor.h
> @@ -669,6 +669,10 @@ weston_surface_unmap(struct weston_surface *surface);
> void
> weston_buffer_post_release(struct wl_buffer *buffer);
>
> +void
> +weston_buffer_reference(struct wl_buffer **ref, struct wl_buffer *buffer,
> + struct wl_listener *buffer_destroy_listener);
> +
> uint32_t
> weston_compositor_get_time(void);
>
> --
> 1.7.8.6
>
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