Add reject round trip to dnd protocol

This lets a drag target reject a drop.

clients/dnd.c

@@ -271,9 +271,16 @@ drag_finish(void *data, struct wl_drag *drag, int fd)
 	free(dnd_drag);
 }
 
+static void
+drag_reject(void *data, struct wl_drag *drag)
+{
+	fprintf(stderr, "drop rejected\n");
+}
+
 static const struct wl_drag_listener drag_listener = {
 	drag_target,
-	drag_finish
+	drag_finish,
+	drag_reject
 };
 
 static void
@@ -379,10 +386,7 @@ drag_offer_drop(void *data, struct wl_drag_offer *offer)
 
 	if (!dnd_offer->drag_type) {
 		fprintf(stderr, "got 'drop', but no target\n");
-		/* FIXME: Should send response so compositor and
-		 * source knows it's over. Can't send -1 to indicate
-		 * 'no target' though becauses of the way fd passing
-		 * currently works.  */
+		wl_drag_offer_reject(offer);
 		return;
 	}
 

compositor/compositor.c

@@ -1137,9 +1137,19 @@ drag_offer_receive(struct wl_client *client,
 	close(fd);
 }
 
+static void
+drag_offer_reject(struct wl_client *client, struct wl_drag_offer *offer)
+{
+	struct wl_drag *drag = container_of(offer, struct wl_drag, drag_offer);
+
+	wl_client_post_event(drag->source->client, &drag->resource.base,
+			     WL_DRAG_REJECT);
+}
+
 static const struct wl_drag_offer_interface drag_offer_interface = {
 	drag_offer_accept,
-	drag_offer_receive
+	drag_offer_receive,
+	drag_offer_reject
 };
 
 static void

protocol/wayland.xml

@@ -209,6 +209,8 @@
     <event name="finish">
       <arg name="fd" type="fd"/>
     </event>
+
+    <event name="reject"/>
   </interface>
 
 
@@ -226,6 +228,9 @@
       <arg name="fd" type="fd"/>
     </request>
 
+    <!-- Called to reject a drop  -->
+    <request name="reject"/>
+
     <!-- Sent before the pointer_focus event to announce the types
          offered.  One event per offered mime type. -->
     <event name="offer">