tests: Add testforeign

Add a test for exporting a handle. There are no GTK+ API for this, but
only per backend GDK API, and so far only Wayland is supported. There
is a private GdkWindow API but it's not exposed externally.

https://bugzilla.gnome.org/show_bug.cgi?id=782325

tests/Makefile.am

@@ -176,6 +176,10 @@ noinst_PROGRAMS =  $(TEST_PROGS)	\
 	testpopupat			\
 	$(NULL)
 
+if USE_WAYLAND
+noinst_PROGRAMS += testforeign
+endif
+
 if USE_X11
 noinst_PROGRAMS += testerrors
 endif
@@ -365,6 +369,9 @@ testfontchooserdialog_SOURCES = \
 testfontoptions_SOURCES = \
 	testfontoptions.c
 
+testforeign_SOURCES = \
+	testforeign.c
+
 testgrid_SOURCES =	\
 	testgrid.c
 

tests/testforeign.c

@@ -0,0 +1,117 @@
+#include <gtk/gtk.h>
+#include <gdk/wayland/gdkwayland.h>
+
+static GtkWidget *window;
+static GtkWidget *label;
+static GtkWidget *entry;
+static GtkWidget *unexport_button;
+static char *export_handle;
+int export_count;
+
+static void
+update_ui (void)
+{
+  gboolean can_unexport;
+  char *label_text;
+
+  gtk_entry_set_text (GTK_ENTRY (entry), export_handle ? export_handle : "");
+
+  label_text = g_strdup_printf ("Export count: %d", export_count);
+  gtk_label_set_text (GTK_LABEL (label), label_text);
+  g_free (label_text);
+
+  can_unexport = !!export_handle;
+  gtk_widget_set_sensitive (unexport_button, can_unexport);
+}
+
+static void
+exported_callback (GdkWindow  *window,
+                   const char *handle,
+                   gpointer    user_data)
+{
+  if (!export_handle)
+    export_handle = g_strdup (handle);
+
+  g_assert (g_str_equal (handle, export_handle));
+
+  export_count++;
+
+  update_ui ();
+}
+
+static void
+export_callback (GtkWidget *widget,
+                 gpointer   data)
+{
+  if (!gdk_wayland_window_export_handle (gtk_widget_get_window (window),
+                                         exported_callback,
+                                         g_strdup ("user_data"), g_free))
+    g_error ("Failed to export window");
+
+  update_ui ();
+}
+
+static void
+unexport_callback (GtkWidget *widget,
+                   gpointer   data)
+{
+  gdk_wayland_window_unexport_handle (gtk_widget_get_window (window));
+
+  export_count--;
+  if (export_count == 0)
+    g_clear_pointer (&export_handle, g_free);
+
+  update_ui ();
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  GdkDisplay *display;
+  GtkWidget *vbox;
+  GtkWidget *hbox;
+  GtkWidget *export_button;
+
+  gtk_init (&argc, &argv);
+
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+
+  display = gtk_widget_get_display (window);
+  if (!GDK_IS_WAYLAND_DISPLAY (display))
+    g_error ("This test is only works on Wayland");
+
+  vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 10);
+  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 10);
+
+  label = gtk_label_new (NULL);
+  entry = gtk_entry_new ();
+  gtk_editable_set_editable (GTK_EDITABLE (entry), FALSE);
+
+  export_button = gtk_button_new_with_label ("Export");
+  unexport_button = gtk_button_new_with_label("Unexport");
+  g_signal_connect (export_button, "clicked",
+                    G_CALLBACK (export_callback), NULL);
+  g_signal_connect (unexport_button, "clicked",
+                    G_CALLBACK (unexport_callback), NULL);
+
+  gtk_container_add (GTK_CONTAINER (hbox), export_button);
+  gtk_container_add (GTK_CONTAINER (hbox), unexport_button);
+
+  gtk_container_add (GTK_CONTAINER (vbox), entry);
+  gtk_container_add (GTK_CONTAINER (vbox), label);
+  gtk_container_add (GTK_CONTAINER (vbox), hbox);
+
+  gtk_container_add (GTK_CONTAINER (window), vbox);
+
+  update_ui ();
+
+  g_signal_connect (window, "delete-event", G_CALLBACK (gtk_main_quit), NULL);
+
+  gtk_widget_show_all (window);
+
+  gtk_main ();
+
+  return 0;
+}