1 files changed, 80 insertions, 0 deletions
diff --git a/src/event/WakeFD.hxx b/src/event/WakeFD.hxx
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+++ b/src/event/WakeFD.hxx
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+/*
+ * 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.
+ */
+
+#ifndef MPD_WAKE_FD_HXX
+#define MPD_WAKE_FD_HXX
+
+#include "check.h"
+
+#include <assert.h>
+
+/**
+ * This class can be used to wake up an I/O event loop.
+ *
+ * For optimization purposes, this class does not have a constructor
+ * or a destructor.
+ */
+class WakeFD {
+	int fds[2];
+
+public:
+#ifdef NDEBUG
+	WakeFD() = default;
+#else
+	WakeFD():fds{-1, -1} {};
+#endif
+
+	WakeFD(const WakeFD &other) = delete;
+	WakeFD &operator=(const WakeFD &other) = delete;
+
+	bool Create();
+	void Destroy();
+
+	int Get() const {
+		assert(fds[0] >= 0);
+#ifndef HAVE_EVENTFD
+		assert(fds[1] >= 0);
+#endif
+
+		return fds[0];
+	}
+
+	/**
+	 * Checks if Write() was called at least once since the last
+	 * Read() call.
+	 */
+	bool Read();
+
+	/**
+	 * Wakes up the reader.  Multiple calls to this function will
+	 * be combined to one wakeup.
+	 */
+	void Write();
+
+private:
+#ifdef HAVE_EVENTFD
+	bool IsEventFD() {
+		assert(fds[0] >= 0);
+
+		return fds[1] == -2;
+	}
+#endif
+};
+
+#endif /* MAIN_NOTIFY_H */