weston-log-wayland: make stream_destroy() use weston_log_subscriber_release()

Make stream_destroy() use weston_log_subscriber_release().
This avoids code duplication and allow us to destroy
weston_log_subscriber_get_only_subscription(), since it's
being used only in this case and it's internal.

Calls for weson_log_subscriber_release() leads to
weston_log_debug_wayland_to_destroy(), which should not
send an error event when the stream has already been closed.

Also, stream_destroy() shouldn't lead to an event error, as
it is a wl_resource destroy handler. So close the stream before
calling weston_log_subscriber_release() in stream_destroy()

Signed-off-by: Leandro Ribeiro <leandrohr@riseup.net>

libweston/weston-log-internal.h

@@ -72,9 +72,6 @@ weston_log_subscription_create(struct weston_log_subscriber *owner,
 void
 weston_log_subscription_destroy(struct weston_log_subscription *sub);
 
-struct weston_log_subscription *
-weston_log_subscriber_get_only_subscription(struct weston_log_subscriber *subscriber);
-
 void
 weston_log_subscription_add(struct weston_log_scope *scope,
 			    struct weston_log_subscription *sub);

libweston/weston-log-wayland.c

@@ -162,6 +162,8 @@ static void
 weston_log_debug_wayland_to_destroy(struct weston_log_subscriber *sub)
 {
 	struct weston_log_debug_wayland *stream = to_weston_log_debug_wayland(sub);
+
+	if (stream->fd != -1)
 		stream_close_on_failure(stream, "debug name removed");
 }
 
@@ -201,20 +203,10 @@ static void
 stream_destroy(struct wl_resource *stream_resource)
 {
 	struct weston_log_debug_wayland *stream;
-	struct weston_log_subscription *sub = NULL;
-
 	stream = wl_resource_get_user_data(stream_resource);
 
-	if (stream->fd != -1)
-		close(stream->fd);
-
-	sub = weston_log_subscriber_get_only_subscription(&stream->base);
-
-	/* we can have a zero subscription if clients tried to subscribe
-	 * to a non-existent scope */
-	if (sub)
-		weston_log_subscription_destroy(sub);
-
+	stream_close_unlink(stream);
+	weston_log_subscriber_release(&stream->base);
 	free(stream);
 }
 

libweston/weston-log.c

@@ -293,30 +293,6 @@ weston_log_subscription_destroy(struct weston_log_subscription *sub)
 	free(sub);
 }
 
-/** Retrieve a subscription by using the subscriber
- *
- * This is useful when trying to find a subscription from the subscriber by
- * having only access to the stream.
- *
- * @param subscriber the subscriber in question
- * @returns a weston_log_subscription object
- *
- * @memberof weston_log_subscription
- */
-struct weston_log_subscription *
-weston_log_subscriber_get_only_subscription(struct weston_log_subscriber *subscriber)
-{
-	struct weston_log_subscription *sub;
-	/* unlikely, but can happen */
-	if (wl_list_length(&subscriber->subscription_list) == 0)
-		return NULL;
-
-	assert(wl_list_length(&subscriber->subscription_list) == 1);
-
-	return wl_container_of(subscriber->subscription_list.prev,
-			       sub, owner_link);
-}
-
 /** Adds the subscription \c sub to the subscription list of the
  * scope.
  *