shell: Explicitly use solid weston_buffers

Rather than punching through to set the surface as a solid colour,
attach an actual weston_buffer to it instead.

This becomes the first user of attaching non-client-generated buffers
to a weston_surface. As a result, it is necessary to introduce a
function which will allow compositors and shells to attach a buffer to a
surface. weston_surface_attach_solid() is therefore introduced as a
special-purpose helper which will attach a solid buffer to a
weston_surface.

It is not intended as a general-purpose mechanism to allow compositors
to attach client-generated buffers to surfaces, as doing so would have
unknown effects on this core part of the compositor itself.

Signed-off-by: Daniel Stone <daniels@collabora.com>

include/libweston/libweston.h

@@ -1776,6 +1776,11 @@ struct weston_buffer_reference *
 weston_buffer_create_solid_rgba(struct weston_compositor *compositor,
 				float r, float g, float b, float a);
 
+void
+weston_surface_attach_solid(struct weston_surface *surface,
+			    struct weston_buffer_reference *buffer_ref,
+			    int w, int h);
+
 void
 weston_buffer_destroy_solid(struct weston_buffer_reference *buffer_ref);
 

libweston/compositor.c

@@ -2595,40 +2595,65 @@ weston_buffer_create_solid_rgba(struct weston_compositor *compositor,
 				float r, float g, float b, float a)
 {
 	struct weston_buffer_reference *ret = zalloc(sizeof(*ret));
+	struct weston_buffer *buffer;
 
 	if (!ret)
 		return NULL;
 
-	ret->buffer = zalloc(sizeof(*ret->buffer));
+	buffer = zalloc(sizeof(*buffer));
-	if (!ret->buffer) {
+	if (!buffer) {
 		free(ret);
 		return NULL;
 	}
 
-	wl_signal_init(&ret->buffer->destroy_signal);
+	wl_signal_init(&buffer->destroy_signal);
-	ret->buffer->type = WESTON_BUFFER_SOLID;
+	buffer->type = WESTON_BUFFER_SOLID;
-	ret->buffer->width = 1;
+	buffer->width = 1;
-	ret->buffer->height = 1;
+	buffer->height = 1;
-	ret->buffer->buffer_origin = ORIGIN_TOP_LEFT;
+	buffer->buffer_origin = ORIGIN_TOP_LEFT;
-	ret->buffer->solid.r = r;
+	buffer->solid.r = r;
-	ret->buffer->solid.g = g;
+	buffer->solid.g = g;
-	ret->buffer->solid.b = b;
+	buffer->solid.b = b;
-	ret->buffer->solid.a = a;
+	buffer->solid.a = a;
 
 	if (a == 1.0) {
-		ret->buffer->pixel_format =
+		buffer->pixel_format =
 			pixel_format_get_info_shm(WL_SHM_FORMAT_XRGB8888);
 	} else {
-		ret->buffer->pixel_format =
+		buffer->pixel_format =
 			pixel_format_get_info_shm(WL_SHM_FORMAT_ARGB8888);
 	}
-	ret->buffer->format_modifier = DRM_FORMAT_MOD_LINEAR;
+	buffer->format_modifier = DRM_FORMAT_MOD_LINEAR;
 
-	weston_buffer_reference(ret, ret->buffer, BUFFER_MAY_BE_ACCESSED);
+	weston_buffer_reference(ret, buffer, BUFFER_MAY_BE_ACCESSED);
 
 	return ret;
 }
 
+WL_EXPORT void
+weston_surface_attach_solid(struct weston_surface *surface,
+			    struct weston_buffer_reference *buffer_ref,
+			    int w, int h)
+{
+	struct weston_buffer *buffer = buffer_ref->buffer;
+
+	assert(buffer);
+	assert(buffer->type == WESTON_BUFFER_SOLID);
+	weston_buffer_reference(&surface->buffer_ref, buffer,
+				BUFFER_MAY_BE_ACCESSED);
+	surface->compositor->renderer->attach(surface, buffer);
+
+	weston_surface_set_size(surface, w, h);
+
+	pixman_region32_fini(&surface->opaque);
+	if (buffer->solid.a == 1.0) {
+		surface->is_opaque = true;
+		pixman_region32_init_rect(&surface->opaque, 0, 0, w, h);
+	} else {
+		pixman_region32_init(&surface->opaque);
+	}
+}
+
 WL_EXPORT void
 weston_buffer_destroy_solid(struct weston_buffer_reference *buffer_ref)
 {

shell-utils/shell-utils.c

@@ -144,6 +144,7 @@ weston_curtain_create(struct weston_compositor *compositor,
 {
 	struct weston_curtain *curtain;
 	struct weston_surface *surface = NULL;
+	struct weston_buffer_reference *buffer_ref;
 	struct weston_view *view;
 
 	curtain = zalloc(sizeof(*curtain));
@@ -158,22 +159,23 @@ weston_curtain_create(struct weston_compositor *compositor,
 	if (view == NULL)
 		goto err_surface;
 
+	buffer_ref = weston_buffer_create_solid_rgba(compositor,
+						     params->r,
+						     params->g,
+						     params->b,
+						     params->a);
+	if (buffer_ref == NULL)
+		goto err_view;
+
+	curtain->view = view;
+	curtain->buffer_ref = buffer_ref;
+
+	weston_surface_set_label_func(surface, params->get_label);
 	surface->committed = params->surface_committed;
 	surface->committed_private = params->surface_private;
 
-	curtain->view = view;
+	weston_surface_attach_solid(surface, buffer_ref, params->width,
-
+				    params->height);
-	weston_surface_set_color(surface,
-				 params->r, params->g, params->b, params->a);
-	weston_surface_set_label_func(surface, params->get_label);
-
-	pixman_region32_fini(&surface->opaque);
-	if (params->a == 1.0) {
-		pixman_region32_init_rect(&surface->opaque, 0, 0,
-					  params->width, params->height);
-	} else {
-		pixman_region32_init(&surface->opaque);
-	}
 
 	pixman_region32_fini(&surface->input);
 	if (params->capture_input) {
@@ -183,11 +185,12 @@ weston_curtain_create(struct weston_compositor *compositor,
 		pixman_region32_init(&surface->input);
 	}
 
-	weston_surface_set_size(surface, params->width, params->height);
 	weston_view_set_position(view, params->x, params->y);
 
 	return curtain;
 
+err_view:
+	weston_view_destroy(view);
 err_surface:
 	weston_surface_destroy(surface);
 err_curtain:
@@ -204,5 +207,6 @@ weston_curtain_destroy(struct weston_curtain *curtain)
 
 	weston_view_destroy(curtain->view);
 	weston_surface_destroy(surface);
+	weston_buffer_destroy_solid(curtain->buffer_ref);
 	free(curtain);
 }

shell-utils/shell-utils.h

@@ -38,6 +38,7 @@ struct weston_curtain_params {
 
 struct weston_curtain {
 	struct weston_view *view;
+	struct weston_buffer_reference *buffer_ref;
 };
 
 struct weston_output *