gio: Add stub test program for GMemoryMonitor

"memory-monitor --watch" will watch over any events coming from either
low-memory-monitor or the portal.

gio/tests/memory-monitor.c

@@ -0,0 +1,88 @@
+/* GIO - GLib Input, Output and Streaming Library
+ *
+ * Copyright 2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gio/gio.h>
+
+static const char *
+get_level_string (GMemoryMonitorWarningLevel level)
+{
+  GEnumClass *eclass;
+  GEnumValue *value;
+
+  eclass = G_ENUM_CLASS (g_type_class_peek (G_TYPE_MEMORY_MONITOR_WARNING_LEVEL));
+  value = g_enum_get_value (eclass, level);
+
+  if (value == NULL)
+    return "unknown";
+
+  return value->value_nick;
+}
+
+static void
+test_dup_default (void)
+{
+  GMemoryMonitor *monitor;
+
+  monitor = g_memory_monitor_dup_default ();
+  g_assert_nonnull (monitor);
+  g_object_unref (monitor);
+}
+
+static void
+warning_cb (GMemoryMonitor *m,
+	    GMemoryMonitorWarningLevel level)
+{
+  const char *str;
+
+  str = get_level_string (level);
+  g_debug ("Warning level: %s (%d)", str , level);
+}
+
+static void
+do_watch_memory (void)
+{
+  GMemoryMonitor *m;
+  GMainLoop *loop;
+
+  m = g_memory_monitor_dup_default ();
+  g_signal_connect (G_OBJECT (m), "low-memory-warning",
+		    G_CALLBACK (warning_cb), NULL);
+
+  loop = g_main_loop_new (NULL, TRUE);
+  g_main_loop_run (loop);
+}
+
+int
+main (int argc, char **argv)
+{
+  int ret;
+
+  if (argc == 2 && !strcmp (argv[1], "--watch"))
+    {
+      do_watch_memory ();
+      return 0;
+    }
+
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/memory-monitor/default", test_dup_default);
+
+  ret = g_test_run ();
+
+  return ret;
+}

gio/tests/meson.build

@@ -53,6 +53,7 @@ gio_tests = {
   'inet-address' : {},
   'io-stream' : {},
   'memory-input-stream' : {},
+  'memory-monitor' : {},
   'memory-output-stream' : {},
   'mount-operation' : {},
   'network-address' : {'extra_sources': ['mock-resolver.c']},