compositor: send the output_created signal after inserting it in the list

The compositor's output_created signal used to be sent in weston_output_init()
which the backend call before putting the output in the output_list.
This caused problems when creating a new view in a listener to that signal,
because weston_view_assign_output() doesn't yet know the new output exists.
To fix this add a new weston_composito_add_output() func which adds the
output in the list and later sends the signal, and make the backends call
that.

src/compositor-drm.c

@@ -2125,7 +2125,7 @@ create_output_for_connector(struct drm_compositor *ec,
 		weston_log("Failed to initialize backlight\n");
 	}
 
-	wl_list_insert(ec->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&ec->base, &output->base);
 
 	find_and_parse_output_edid(ec, output, connector);
 	if (connector->connector_type == DRM_MODE_CONNECTOR_LVDS)

src/compositor-fbdev.c

@@ -581,7 +581,7 @@ fbdev_output_create(struct fbdev_compositor *compositor,
 	output->finish_frame_timer =
 		wl_event_loop_add_timer(loop, finish_frame_handler, output);
 
-	wl_list_insert(compositor->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&compositor->base, &output->base);
 
 	weston_log("fbdev output %d×%d px\n",
 	           output->mode.width, output->mode.height);

src/compositor-headless.c

@@ -169,7 +169,7 @@ headless_compositor_create_output(struct headless_compositor *c,
 						  output->image);
 	}
 
-	wl_list_insert(c->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&c->base, &output->base);
 
 	return 0;
 }

src/compositor-rdp.c

@@ -488,7 +488,7 @@ rdp_compositor_create_output(struct rdp_compositor *c, int width, int height)
 	output->base.switch_mode = rdp_switch_mode;
 	c->output = output;
 
-	wl_list_insert(c->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&c->base, &output->base);
 	return 0;
 
 out_shadow_surface:

src/compositor-rpi.c

@@ -357,7 +357,7 @@ rpi_output_create(struct rpi_compositor *compositor, uint32_t transform)
 	if (rpi_renderer_output_create(&output->base, output->display) < 0)
 		goto out_output;
 
-	wl_list_insert(compositor->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&compositor->base, &output->base);
 
 	weston_log("Raspberry Pi HDMI output %dx%d px\n",
 		   output->mode.width, output->mode.height);

src/compositor-wayland.c

@@ -1057,7 +1057,7 @@ wayland_output_create(struct wayland_compositor *c, int x, int y,
 	output->base.set_dpms = NULL;
 	output->base.switch_mode = wayland_output_switch_mode;
 
-	wl_list_insert(c->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&c->base, &output->base);
 
 	return output;
 

src/compositor-x11.c

@@ -915,7 +915,7 @@ x11_compositor_create_output(struct x11_compositor *c, int x, int y,
 	output->finish_frame_timer =
 		wl_event_loop_add_timer(loop, finish_frame_handler, output);
 
-	wl_list_insert(c->base.output_list.prev, &output->base.link);
+	weston_compositor_add_output(&c->base, &output->base);
 
 	weston_log("x11 output %dx%d, window id %d\n",
 		   width, height, output->window);

src/compositor.c

@@ -4125,7 +4125,20 @@ weston_output_init(struct weston_output *output, struct weston_compositor *c,
 	output->global =
 		wl_global_create(c->wl_display, &wl_output_interface, 2,
 				 output, bind_output);
-	wl_signal_emit(&c->output_created_signal, output);
+}
+
+/** Adds an output to the compositor's output list and
+ *  send the compositor's output_created signal.
+ *
+ * \param compositor The compositor instance.
+ * \param output The output to be added.
+ */
+WL_EXPORT void
+weston_compositor_add_output(struct weston_compositor *compositor,
+                             struct weston_output *output)
+{
+	wl_list_insert(compositor->output_list.prev, &output->link);
+	wl_signal_emit(&compositor->output_created_signal, output);
 }
 
 WL_EXPORT void

src/compositor.h

@@ -1374,6 +1374,9 @@ void
 weston_output_init(struct weston_output *output, struct weston_compositor *c,
 		   int x, int y, int width, int height, uint32_t transform, int32_t scale);
 void
+weston_compositor_add_output(struct weston_compositor *compositor,
+                             struct weston_output *output);
+void
 weston_output_destroy(struct weston_output *output);
 void
 weston_output_transform_coordinate(struct weston_output *output,