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Diffstat (limited to '')
-rw-r--r-- | src/event/WakeFD.hxx | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/event/WakeFD.hxx b/src/event/WakeFD.hxx new file mode 100644 index 000000000..15b66b4cf --- /dev/null +++ b/src/event/WakeFD.hxx @@ -0,0 +1,80 @@ +/* + * 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 */ |