path: root/libstdc++-v3/include/std/mutex

// <mutex> -*- C++ -*-

// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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 3, 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 General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file mutex
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_MUTEX
#define _GLIBCXX_MUTEX 1

#pragma GCC system_header

#ifndef __GXX_EXPERIMENTAL_CXX0X__
# include <c++0x_warning.h>
#else

#include <tuple>
#include <cstddef>
#include <chrono>
#include <exception>
#include <type_traits>
#include <functional>
#include <system_error>
#include <bits/functexcept.h>
#include <bits/gthr.h>
#include <bits/move.h> // for std::swap

#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)

namespace std
{
  /**
   * @defgroup mutexes Mutexes
   * @ingroup concurrency
   *
   * Classes for mutex support.
   * @{
   */

  /// mutex
  class mutex
  {
    typedef __gthread_mutex_t			__native_type;
    __native_type  _M_mutex;

  public:
    typedef __native_type* 			native_handle_type;

    mutex()
    {
      // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
#ifdef __GTHREAD_MUTEX_INIT
      __native_type __tmp = __GTHREAD_MUTEX_INIT;
      _M_mutex = __tmp;
#else
      __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
    }

    mutex(const mutex&) = delete;
    mutex& operator=(const mutex&) = delete;

    void
    lock()
    {
      int __e = __gthread_mutex_lock(&_M_mutex);

      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
      if (__e)
	__throw_system_error(__e);
    }

    bool
    try_lock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      return !__gthread_mutex_trylock(&_M_mutex);
    }

    void
    unlock()
    {
      // XXX EINVAL, EAGAIN, EPERM
      __gthread_mutex_unlock(&_M_mutex);
    }

    native_handle_type
    native_handle()
    { return &_M_mutex; }
  };

  /// recursive_mutex
  class recursive_mutex
  {
    typedef __gthread_recursive_mutex_t		__native_type;
    __native_type  _M_mutex;

  public:
    typedef __native_type* 			native_handle_type;

    recursive_mutex()
    {
      // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT
      __native_type __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
      _M_mutex = __tmp;
#else
      __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
    }

    recursive_mutex(const recursive_mutex&) = delete;
    recursive_mutex& operator=(const recursive_mutex&) = delete;

    void
    lock()
    {
      int __e = __gthread_recursive_mutex_lock(&_M_mutex);

      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
      if (__e)
	__throw_system_error(__e);
    }

    bool
    try_lock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      return !__gthread_recursive_mutex_trylock(&_M_mutex);
    }

    void
    unlock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      __gthread_recursive_mutex_unlock(&_M_mutex);
    }

    native_handle_type
    native_handle()
    { return &_M_mutex; }
  };

  /// timed_mutex
  class timed_mutex
  {
    typedef __gthread_mutex_t 		  	__native_type;

#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC
    typedef chrono::monotonic_clock 	  	__clock_t;
#else
    typedef chrono::high_resolution_clock 	__clock_t;
#endif

    __native_type  _M_mutex;

  public:
    typedef __native_type* 		  	native_handle_type;

    timed_mutex()
    {
#ifdef __GTHREAD_MUTEX_INIT
      __native_type __tmp = __GTHREAD_MUTEX_INIT;
      _M_mutex = __tmp;
#else
      __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
    }

    timed_mutex(const timed_mutex&) = delete;
    timed_mutex& operator=(const timed_mutex&) = delete;

    void
    lock()
    {
      int __e = __gthread_mutex_lock(&_M_mutex);

      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
      if (__e)
	__throw_system_error(__e);
    }

    bool
    try_lock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      return !__gthread_mutex_trylock(&_M_mutex);
    }

    template <class _Rep, class _Period>
      bool
      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
      { return __try_lock_for_impl(__rtime); }

    template <class _Clock, class _Duration>
      bool
      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
      {
	chrono::time_point<_Clock, chrono::seconds> __s =
	  chrono::time_point_cast<chrono::seconds>(__atime);

	chrono::nanoseconds __ns =
	  chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

	__gthread_time_t __ts = {
	  static_cast<std::time_t>(__s.time_since_epoch().count()),
	  static_cast<long>(__ns.count())
	};

	return !__gthread_mutex_timedlock(&_M_mutex, &__ts);
      }

    void
    unlock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      __gthread_mutex_unlock(&_M_mutex);
    }

    native_handle_type
    native_handle()
    { return &_M_mutex; }

  private:
    template<typename _Rep, typename _Period>
      typename enable_if<
	ratio_less_equal<__clock_t::period, _Period>::value, bool>::type
      __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime)
      {
	__clock_t::time_point __atime = __clock_t::now()
	  + chrono::duration_cast<__clock_t::duration>(__rtime);

	return try_lock_until(__atime);
      }

    template <typename _Rep, typename _Period>
      typename enable_if<
	!ratio_less_equal<__clock_t::period, _Period>::value, bool>::type
      __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime)
      {
	__clock_t::time_point __atime = __clock_t::now()
	  + ++chrono::duration_cast<__clock_t::duration>(__rtime);

	return try_lock_until(__atime);
      }
  };

  /// recursive_timed_mutex
  class recursive_timed_mutex
  {
    typedef __gthread_recursive_mutex_t		__native_type;

#ifdef _GLIBCXX_USE_CLOCK_MONOTONIC
    typedef chrono::monotonic_clock 		__clock_t;
#else
    typedef chrono::high_resolution_clock 	__clock_t;
#endif

    __native_type  _M_mutex;

  public:
    typedef __native_type* 			native_handle_type;

    recursive_timed_mutex()
    {
      // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT
      __native_type __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
      _M_mutex = __tmp;
#else
      __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
    }

    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;

    void
    lock()
    {
      int __e = __gthread_recursive_mutex_lock(&_M_mutex);

      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
      if (__e)
	__throw_system_error(__e);
    }

    bool
    try_lock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      return !__gthread_recursive_mutex_trylock(&_M_mutex);
    }

    template <class _Rep, class _Period>
      bool
      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
      { return __try_lock_for_impl(__rtime); }

    template <class _Clock, class _Duration>
      bool
      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
      {
	chrono::time_point<_Clock, chrono::seconds>  __s =
	  chrono::time_point_cast<chrono::seconds>(__atime);

	chrono::nanoseconds __ns =
	  chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

	__gthread_time_t __ts = {
	  static_cast<std::time_t>(__s.time_since_epoch().count()),
	  static_cast<long>(__ns.count())
	};

	return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts);
      }

    void
    unlock()
    {
      // XXX EINVAL, EAGAIN, EBUSY
      __gthread_recursive_mutex_unlock(&_M_mutex);
    }

    native_handle_type
    native_handle()
    { return &_M_mutex; }

  private:
    template<typename _Rep, typename _Period>
      typename enable_if<
	ratio_less_equal<__clock_t::period, _Period>::value, bool>::type
      __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime)
      {
	__clock_t::time_point __atime = __clock_t::now()
	  + chrono::duration_cast<__clock_t::duration>(__rtime);

	return try_lock_until(__atime);
      }

    template <typename _Rep, typename _Period>
      typename enable_if<
	!ratio_less_equal<__clock_t::period, _Period>::value, bool>::type
      __try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime)
      {
	__clock_t::time_point __atime = __clock_t::now()
	  + ++chrono::duration_cast<__clock_t::duration>(__rtime);

	return try_lock_until(__atime);
      }
  };

  /// Do not acquire ownership of the mutex.
  struct defer_lock_t { };

  /// Try to acquire ownership of the mutex without blocking.
  struct try_to_lock_t { };

  /// Assume the calling thread has already obtained mutex ownership
  /// and manage it.
  struct adopt_lock_t { };

  extern const defer_lock_t	defer_lock;
  extern const try_to_lock_t	try_to_lock;
  extern const adopt_lock_t	adopt_lock;

  /** 
   *  @brief Thrown to indicate errors with lock operations.
   *
   *  @ingroup exceptions
   */
  class lock_error : public exception
  {
  public:
    virtual const char*
    _GLIBCXX_CONST what() const throw();
  };

  /// @brief  Scoped lock idiom.
  // Acquire the mutex here with a constructor call, then release with
  // the destructor call in accordance with RAII style.
  template<typename _Mutex>
    class lock_guard
    {
    public:
      typedef _Mutex mutex_type;

      explicit lock_guard(mutex_type& __m) : _M_device(__m)
      { _M_device.lock(); }

      lock_guard(mutex_type& __m, adopt_lock_t __a) : _M_device(__m)
      { _M_device.lock(); }

      ~lock_guard()
      { _M_device.unlock(); }

      lock_guard(const lock_guard&) = delete;
      lock_guard& operator=(const lock_guard&) = delete;

    private:
      mutex_type&  _M_device;
    };

  /// unique_lock
  template<typename _Mutex>
    class unique_lock
    {
    public:
      typedef _Mutex mutex_type;

      unique_lock()
      : _M_device(0), _M_owns(false)
      { }

      explicit unique_lock(mutex_type& __m)
      : _M_device(&__m), _M_owns(false)
      {
	lock();
	_M_owns = true;
      }

      unique_lock(mutex_type& __m, defer_lock_t)
      : _M_device(&__m), _M_owns(false)
      { }

      unique_lock(mutex_type& __m, try_to_lock_t)
      : _M_device(&__m), _M_owns(_M_device->try_lock())
      { }

      unique_lock(mutex_type& __m, adopt_lock_t)
      : _M_device(&__m), _M_owns(true)
      {
	// XXX calling thread owns mutex
      }

      template<typename _Clock, typename _Duration>
	unique_lock(mutex_type& __m,
		    const chrono::time_point<_Clock, _Duration>& __atime)
	: _M_device(&__m), _M_owns(_M_device->try_lock_until(__atime))
	{ }

      template<typename _Rep, typename _Period>
	unique_lock(mutex_type& __m,
		    const chrono::duration<_Rep, _Period>& __rtime)
	: _M_device(&__m), _M_owns(_M_device->try_lock_for(__rtime))
	{ }

      ~unique_lock()
      {
	if (_M_owns)
	  unlock();
      }

      unique_lock(const unique_lock&) = delete;
      unique_lock& operator=(const unique_lock&) = delete;

      unique_lock(unique_lock&& __u)
      : _M_device(__u._M_device), _M_owns(__u._M_owns)
      {
	__u._M_device = 0;
	__u._M_owns = false;
      }

      unique_lock& operator=(unique_lock&& __u)
      {
	if(_M_owns)
	  unlock();

	unique_lock(std::move(__u)).swap(*this);

	__u._M_device = 0;
	__u._M_owns = false;

	return *this;
      }

      void
      lock()
      {
	if (!_M_device)
	  __throw_system_error(int(errc::operation_not_permitted));
	else if (_M_owns)
	  __throw_system_error(int(errc::resource_deadlock_would_occur));
	else
	  {
	    _M_device->lock();
	    _M_owns = true;
	  }
      }

      bool
      try_lock()
      {
	if (!_M_device)
	  __throw_system_error(int(errc::operation_not_permitted));
	else if (_M_owns)
	  __throw_system_error(int(errc::resource_deadlock_would_occur));
	else
	  {
	    _M_owns = _M_device->try_lock();
	    return _M_owns;
	  }
      }

      template<typename _Clock, typename _Duration>
	bool
	try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
	{
	  if (!_M_device)
	    __throw_system_error(int(errc::operation_not_permitted));
	  else if (_M_owns)
	    __throw_system_error(int(errc::resource_deadlock_would_occur));
	  else
	    {
	      _M_owns = _M_device->try_lock_until(__atime);
	      return _M_owns;
	    }
	}

      template<typename _Rep, typename _Period>
	bool
	try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
	{
	  if (!_M_device)
	    __throw_system_error(int(errc::operation_not_permitted));
	  else if (_M_owns)
	    __throw_system_error(int(errc::resource_deadlock_would_occur));
	  else
	    {
	      _M_owns = _M_device->try_lock_for(__rtime);
	      return _M_owns;
	    }
	 }

      void
      unlock()
      {
	if (!_M_owns)
	  __throw_system_error(int(errc::operation_not_permitted));
	else if (_M_device)
	  {
	    _M_device->unlock();
	    _M_owns = false;
	  }
      }

      void
      swap(unique_lock&& __u)
      {
	std::swap(_M_device, __u._M_device);
	std::swap(_M_owns, __u._M_owns);
      }

      mutex_type*
      release()
      {
	mutex_type* __ret = _M_device;
	_M_device = 0;
	_M_owns = false;
	return __ret;
      }

      bool
      owns_lock() const
      { return _M_owns; }

      /* explicit */ operator bool () const
      { return owns_lock(); }

      mutex_type*
      mutex() const
      { return _M_device; }

    private:
      mutex_type*	_M_device;
      bool		_M_owns; // XXX use atomic_bool
    };

  template<typename _Mutex>
    inline void
    swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y)
    { __x.swap(__y); }

  template<typename _Mutex>
    inline void
    swap(unique_lock<_Mutex>&& __x, unique_lock<_Mutex>& __y)
    { __x.swap(__y); }

  template<typename _Mutex>
    inline void
    swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>&& __y)
    { __x.swap(__y); }

  template<int _Idx>
    struct __unlock_impl
    {
      template<typename... _Lock>
	static void
	__do_unlock(tuple<_Lock&...>& __locks)
	{
	  std::get<_Idx>(__locks).unlock();
	  __unlock_impl<_Idx - 1>::__do_unlock(__locks);
	}
    };

  template<>
    struct __unlock_impl<-1>
    {
      template<typename... _Lock>
	static void
	__do_unlock(tuple<_Lock&...>&)
	{ }
    };

  template<int _Idx, bool _Continue = true>
    struct __try_lock_impl
    {
      template<typename... _Lock>
	static int
	__do_try_lock(tuple<_Lock&...>& __locks)
	{
	  if(std::get<_Idx>(__locks).try_lock())
	    {
	      return __try_lock_impl<_Idx + 1,
		_Idx + 2 < sizeof...(_Lock)>::__do_try_lock(__locks);
	    }
	  else
	    {
	      __unlock_impl<_Idx>::__do_unlock(__locks);
	      return _Idx;
	    }
	}
    };

  template<int _Idx>
    struct __try_lock_impl<_Idx, false>
    {
      template<typename... _Lock>
	static int
	__do_try_lock(tuple<_Lock&...>& __locks)
	{
	  if(std::get<_Idx>(__locks).try_lock())
	    return -1;
	  else
	    {
	      __unlock_impl<_Idx>::__do_unlock(__locks);
	      return _Idx;
	    }
	}
    };

  /** @brief Generic try_lock.
   *  @param __l1 Meets Mutex requirements (try_lock() may throw).
   *  @param __l2 Meets Mutex requirements (try_lock() may throw).
   *  @param __l3 Meets Mutex requirements (try_lock() may throw).
   *  @return Returns -1 if all try_lock() calls return true. Otherwise returns
   *          a 0-based index corresponding to the argument that returned false.
   *  @post Either all arguments are locked, or none will be.
   *
   *  Sequentially calls try_lock() on each argument.
   */
  template<typename _Lock1, typename _Lock2, typename... _Lock3>
    int
    try_lock(_Lock1& __l1, _Lock2& __l2, _Lock3&... __l3)
    {
      tuple<_Lock1&, _Lock2&, _Lock3&...> __locks(__l1, __l2, __l3...);
      return __try_lock_impl<0>::__do_try_lock(__locks);
    }

  /// lock
  template<typename _L1, typename _L2, typename ..._L3>
    void
    lock(_L1&, _L2&, _L3&...);

  /// once_flag
  struct once_flag
  {
  private:
    typedef __gthread_once_t __native_type;
    __native_type  _M_once;

  public:
    once_flag()
    {
      __native_type __tmp = __GTHREAD_ONCE_INIT;
      _M_once = __tmp;
    }

    once_flag(const once_flag&) = delete;
    once_flag& operator=(const once_flag&) = delete;

    template<typename _Callable, typename... _Args>
      friend void
      call_once(once_flag& __once, _Callable __f, _Args&&... __args);
  };

#ifdef _GLIBCXX_HAVE_TLS
  extern __thread void* __once_callable;
  extern __thread void (*__once_call)();

  template<typename _Callable>
    inline void
    __once_call_impl()
    {
      (*(_Callable*)__once_callable)();
    }
#else
  extern function<void()> __once_functor;
  extern unique_lock<mutex>* __once_functor_lock;

  extern mutex&
  __get_once_mutex();
#endif

  extern "C" void __once_proxy();

  /// call_once
  template<typename _Callable, typename... _Args>
    void
    call_once(once_flag& __once, _Callable __f, _Args&&... __args)
    {
#ifdef _GLIBCXX_HAVE_TLS
      auto __bound_functor = bind(__f, __args...);
      __once_callable = &__bound_functor;
      __once_call = &__once_call_impl<decltype(__bound_functor)>;
#else
      unique_lock<mutex> __functor_lock(__get_once_mutex());
      __once_functor = bind(__f, __args...);
      __once_functor_lock = &__functor_lock;
#endif

      int __e = __gthread_once(&(__once._M_once), &__once_proxy);

      if (__e)
	__throw_system_error(__e);
    }

  // @} group mutexes
}

#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1

#endif // __GXX_EXPERIMENTAL_CXX0X__

#endif // _GLIBCXX_MUTEX