/*
 Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved.
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License, version 2.0,
 as published by the Free Software Foundation.

 This program is also distributed with certain software (including
 but not limited to OpenSSL) that is licensed under separate terms,
 as designated in a particular file or component or in included license
 documentation.  The authors of MySQL hereby grant you an additional
 permission to link the program and your derivative works with the
 separately licensed software that they have included with MySQL.

 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, version 2.0, 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 St, Fifth Floor, Boston, MA 02110-1301  USA
 */

#include "uv.h"

#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
#define CONCURRENTFLAG_USE_GCC_ATOMICS
#else 
#define CONCURRENTFLAG_USE_LIBUV
#endif 
 

class ConcurrentFlag {
public:
  ConcurrentFlag();
  bool test();
  void set();
  void clear();
private:
#ifdef CONCURRENTFLAG_USE_GCC_ATOMICS
  int flag;
#else
  uv_rwlock_t lock;
  bool flag;
#endif
};

#ifdef CONCURRENTFLAG_USE_GCC_ATOMICS

inline ConcurrentFlag::ConcurrentFlag() {
  __sync_fetch_and_and(&flag, 0);
}

inline bool ConcurrentFlag::test() {
  return __sync_fetch_and_and(&flag, 0);
}

inline void ConcurrentFlag::set() {
  __sync_fetch_and_or(&flag, 1);
}

inline void ConcurrentFlag::clear() {
  __sync_fetch_and_and(&flag, 0);
}

#else 

inline ConcurrentFlag::ConcurrentFlag() {
  flag = 0;
  uv_rwlock_init(& lock);
}

inline bool ConcurrentFlag::test() { 
  bool val;
  uv_rwlock_rdlock(& lock);
  val = flag;
  uv_rwlock_rdunlock(& lock);
  return val;
}

inline void ConcurrentFlag::set() {
  uv_rwlock_wrlock(& lock);
  flag = true;
  uv_rwlock_wrunlock(& lock);
}

inline void ConcurrentFlag::clear() {
  uv_rwlock_wrlock(& lock);
  flag = false;
  uv_rwlock_wrunlock(& lock);
}

#endif