1 files changed, 91 insertions, 0 deletions
diff --git a/src/GlobalEvents.cxx b/src/GlobalEvents.cxx
new file mode 100644
index 000000000..20faa9a81
--- /dev/null
+++ b/src/GlobalEvents.cxx
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "GlobalEvents.hxx"
+
+#include <atomic>
+
+#include <assert.h>
+#include <glib.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "global_events"
+
+namespace GlobalEvents {
+	static guint source_id;
+	static std::atomic_uint flags;
+	static Handler handlers[MAX];
+}
+
+/**
+ * Invoke the callback for a certain event.
+ */
+static void
+InvokeGlobalEvent(GlobalEvents::Event event)
+{
+	assert((unsigned)event < GlobalEvents::MAX);
+	assert(GlobalEvents::handlers[event] != NULL);
+
+	GlobalEvents::handlers[event]();
+}
+
+static gboolean
+GlobalEventCallback(G_GNUC_UNUSED gpointer data)
+{
+	const unsigned flags = GlobalEvents::flags.exchange(0);
+
+	for (unsigned i = 0; i < GlobalEvents::MAX; ++i)
+		if (flags & (1u << i))
+			/* invoke the event handler */
+			InvokeGlobalEvent(GlobalEvents::Event(i));
+
+	return false;
+}
+
+void
+GlobalEvents::Initialize()
+{
+}
+
+void
+GlobalEvents::Deinitialize()
+{
+	if (source_id != 0)
+		g_source_remove(source_id);
+}
+
+void
+GlobalEvents::Register(Event event, Handler callback)
+{
+	assert((unsigned)event < MAX);
+	assert(handlers[event] == NULL);
+
+	handlers[event] = callback;
+}
+
+void
+GlobalEvents::Emit(Event event)
+{
+	assert((unsigned)event < MAX);
+
+	const unsigned mask = 1u << unsigned(event);
+	if (GlobalEvents::flags.fetch_or(mask) == 0)
+		source_id = g_idle_add(GlobalEventCallback, nullptr);
+}