client: Add method to get display for a given proxy

This can be useful for additional validation purposes when handling
proxies. This is similar to existing server side API
wl_global_get_display.

Signed-off-by: David Edmundson <david@davidedmundson.co.uk>

src/wayland-client-core.h

@@ -219,6 +219,9 @@ wl_proxy_get_tag(struct wl_proxy *proxy);
 const char *
 wl_proxy_get_class(struct wl_proxy *proxy);
 
+struct wl_display *
+wl_proxy_get_display(struct wl_proxy *proxy);
+
 void
 wl_proxy_set_queue(struct wl_proxy *proxy, struct wl_event_queue *queue);
 

src/wayland-client.c

@@ -2338,6 +2338,20 @@ wl_proxy_get_class(struct wl_proxy *proxy)
 	return proxy->object.interface->name;
 }
 
+/** Get the display of a proxy object
+ *
+ * \param proxy The proxy object
+ * \return The wl_display the proxy is associated with
+ *
+ * \memberof wl_proxy
+ * \since 1.23
+ */
+WL_EXPORT struct wl_display *
+wl_proxy_get_display(struct wl_proxy *proxy)
+{
+	return proxy->display;
+}
+
 /** Assign a proxy to an event queue
  *
  * \param proxy The proxy object

tests/proxy-test.c

@@ -118,6 +118,8 @@ TEST(proxy_tag)
 	wl_proxy_set_tag((struct wl_proxy *) client.callback_b,
 			 &tag_b);
 
+	assert(wl_proxy_get_display((struct wl_proxy *) client.callback_b) == client.display);
+
 	wl_display_flush(client.display);
 
 	while (server.sync_count < 2) {