backend-rdp: extract weston_output_set_single_mode()

The ensure_single_mode() helper replaces an output's single mode.
Extract it into libweston so it can be reused by the VNC backend,
and rename it to weston_output_set_single_mode().

At the same time, set the the previously missing
WL_OUTPUT_MODE_CURRENT flag on the new mode.

Fixes #758

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

libweston/backend-rdp/rdp.c

@@ -333,72 +333,19 @@ finish_frame_handler(void *data)
 	return 1;
 }
 
-static struct weston_mode *
-rdp_insert_new_mode(struct weston_output *output, int width, int height, int rate)
-{
-	struct weston_mode *ret;
-	ret = xzalloc(sizeof *ret);
-	ret->width = width;
-	ret->height = height;
-	ret->refresh = rate;
-	ret->flags = WL_OUTPUT_MODE_PREFERRED;
-	wl_list_insert(&output->mode_list, &ret->link);
-	return ret;
-}
-
-/* It doesn't make sense for RDP to have more than one mode, so
- * we make sure that we have only one.
- */
-static struct weston_mode *
-ensure_single_mode(struct weston_output *output, struct weston_mode *target)
-{
-	struct rdp_output *rdpOutput = to_rdp_output(output);
-	struct rdp_backend *b = rdpOutput->backend;
-	struct weston_mode *iter, *local = NULL, *new_mode;
-
-	wl_list_for_each(iter, &output->mode_list, link) {
-		assert(!local);
-
-		if ((iter->width == target->width) &&
-		    (iter->height == target->height) &&
-		    (iter->refresh == target->refresh)) {
-			return iter;
-		} else {
-			local = iter;
-		}
-	}
-	/* Make sure we create the new one before freeing the old one
-	 * because some mode switch code uses pointer comparisons! If
-	 * we freed the old mode first, malloc could theoretically give
-	 * us back the same pointer.
-	 */
-	new_mode = rdp_insert_new_mode(output,
-				       target->width, target->height,
-				       b->rdp_monitor_refresh_rate);
-	if (local) {
-		wl_list_remove(&local->link);
-		free(local);
-	}
-
-	return new_mode;
-}
-
 static void
 rdp_output_set_mode(struct weston_output *base, struct weston_mode *mode)
 {
 	struct rdp_output *rdpOutput = container_of(base, struct rdp_output, base);
 	struct rdp_backend *b = rdpOutput->backend;
-	struct weston_mode *cur;
 	struct weston_output *output = base;
 	struct rdp_peers_item *rdpPeer;
 	rdpSettings *settings;
 	struct weston_renderbuffer *new_renderbuffer;
 
 	mode->refresh = b->rdp_monitor_refresh_rate;
-	cur = ensure_single_mode(base, mode);
+	weston_output_set_single_mode(base, mode);
 
-	base->current_mode = cur;
-	base->native_mode = cur;
 	if (base->enabled) {
 		const struct weston_renderer *renderer;
 		pixman_image_t *new_image;

libweston/compositor.c

@@ -7414,6 +7414,45 @@ weston_output_get_color_characteristics(struct weston_output *output)
 	return &output->color_characteristics;
 }
 
+WL_EXPORT void
+weston_output_set_single_mode(struct weston_output *output,
+			      struct weston_mode *target)
+{
+	struct weston_mode *iter, *local = NULL, *mode;
+
+	wl_list_for_each(iter, &output->mode_list, link) {
+		assert(!local);
+
+		if ((iter->width == target->width) &&
+		    (iter->height == target->height) &&
+		    (iter->refresh == target->refresh)) {
+			mode = iter;
+			goto out;
+		} else {
+			local = iter;
+		}
+	}
+	/* Make sure we create the new one before freeing the old one
+	 * because some mode switch code uses pointer comparisons! If
+	 * we freed the old mode first, malloc could theoretically give
+	 * us back the same pointer.
+	 */
+	mode = xzalloc(sizeof *mode);
+	mode->width = target->width;
+	mode->height = target->height;
+	mode->refresh = target->refresh;
+	mode->flags = WL_OUTPUT_MODE_CURRENT | WL_OUTPUT_MODE_PREFERRED;
+	wl_list_insert(&output->mode_list, &mode->link);
+out:
+	output->current_mode = mode;
+	output->native_mode = mode;
+
+	if (local) {
+		wl_list_remove(&local->link);
+		free(local);
+	}
+}
+
 /** Initializes a weston_output object with enough data so
  ** an output can be configured.
  *

libweston/libweston-internal.h

@@ -258,6 +258,10 @@ weston_output_disable_planes_incr(struct weston_output *output);
 void
 weston_output_disable_planes_decr(struct weston_output *output);
 
+void
+weston_output_set_single_mode(struct weston_output *output,
+			      struct weston_mode *target);
+
 /* weston_plane */
 
 void