include/mutex

// -*- C++ -*-
//===--------------------------- mutex ------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_MUTEX
#define _LIBCPP_MUTEX

/*
 mutex synopsis

namespace std
{

class mutex
{
public:
 constexpr mutex() noexcept;
 ~mutex();

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

 void lock();
 bool try_lock();
 void unlock();

 typedef pthread_mutex_t* native_handle_type;
 native_handle_type native_handle();
};

class recursive_mutex
{
public:
 recursive_mutex();
 ~recursive_mutex();

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

 void lock();
 bool try_lock() noexcept;
 void unlock();

 typedef pthread_mutex_t* native_handle_type;
 native_handle_type native_handle();
};

class timed_mutex
{
public:
 timed_mutex();
 ~timed_mutex();

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

 void lock();
 bool try_lock();
 template <class Rep, class Period>
 bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
 template <class Clock, class Duration>
 bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
 void unlock();
};

class recursive_timed_mutex
{
public:
 recursive_timed_mutex();
 ~recursive_timed_mutex();

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

 void lock();
 bool try_lock() noexcept;
 template <class Rep, class Period>
 bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
 template <class Clock, class Duration>
 bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
 void unlock();
};

struct defer_lock_t {};
struct try_to_lock_t {};
struct adopt_lock_t {};

constexpr defer_lock_t defer_lock{};
constexpr try_to_lock_t try_to_lock{};
constexpr adopt_lock_t adopt_lock{};

template <class Mutex>
class lock_guard
{
public:
 typedef Mutex mutex_type;

 explicit lock_guard(mutex_type& m);
 lock_guard(mutex_type& m, adopt_lock_t);
 ~lock_guard();

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

template <class... MutexTypes> // Variadic lock_guard only provided in ABI V2.
class lock_guard
{
public:
 explicit lock_guard(MutexTypes&... m);
 lock_guard(MutexTypes&... m, adopt_lock_t);
 ~lock_guard();
 lock_guard(lock_guard const&) = delete;
 lock_guard& operator=(lock_guard const&) = delete;
private:
 tuple<MutexTypes&...> pm; // exposition only
};

template <class Mutex>
class unique_lock
{
public:
 typedef Mutex mutex_type;
 unique_lock() noexcept;
 explicit unique_lock(mutex_type& m);
 unique_lock(mutex_type& m, defer_lock_t) noexcept;
 unique_lock(mutex_type& m, try_to_lock_t);
 unique_lock(mutex_type& m, adopt_lock_t);
 template <class Clock, class Duration>
 unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
 template <class Rep, class Period>
 unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
 ~unique_lock();

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

 unique_lock(unique_lock&& u) noexcept;
 unique_lock& operator=(unique_lock&& u) noexcept;

 void lock();
 bool try_lock();

 template <class Rep, class Period>
 bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
 template <class Clock, class Duration>
 bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);

 void unlock();

 void swap(unique_lock& u) noexcept;
 mutex_type* release() noexcept;

 bool owns_lock() const noexcept;
 explicit operator bool () const noexcept;
 mutex_type* mutex() const noexcept;
};

template <class Mutex>
 void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;

template <class L1, class L2, class... L3>
 int try_lock(L1&, L2&, L3&...);
template <class L1, class L2, class... L3>
 void lock(L1&, L2&, L3&...);

struct once_flag
{
 constexpr once_flag() noexcept;

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

template<class Callable, class ...Args>
 void call_once(once_flag& flag, Callable&& func, Args&&... args);

} // std

*/

#include <__config>
#include <__mutex_base>
#include <functional>
#include <memory>
#ifndef _LIBCPP_HAS_NO_VARIADICS
#include <tuple>
#endif
#include <__threading_support>

#include <__undef_min_max>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#ifndef _LIBCPP_HAS_NO_THREADS

class _LIBCPP_TYPE_VIS recursive_mutex
{
 __libcpp_mutex_t __m_;

public:
 recursive_mutex();
 ~recursive_mutex();

private:
 recursive_mutex(const recursive_mutex&); // = delete;
 recursive_mutex& operator=(const recursive_mutex&); // = delete;

public:
 void lock();
 bool try_lock() _NOEXCEPT;
 void unlock() _NOEXCEPT;

 typedef __libcpp_mutex_t* native_handle_type;
 _LIBCPP_INLINE_VISIBILITY
 native_handle_type native_handle() {return &__m_;}
};

class _LIBCPP_TYPE_VIS timed_mutex
{
 mutex __m_;
 condition_variable __cv_;
 bool __locked_;
public:
 timed_mutex();
 ~timed_mutex();

private:
 timed_mutex(const timed_mutex&); // = delete;
 timed_mutex& operator=(const timed_mutex&); // = delete;

public:
 void lock();
 bool try_lock() _NOEXCEPT;
 template <class _Rep, class _Period>
 _LIBCPP_INLINE_VISIBILITY
 bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
 {return try_lock_until(chrono::steady_clock::now() + __d);}
 template <class _Clock, class _Duration>
 bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
 void unlock() _NOEXCEPT;
};

template <class _Clock, class _Duration>
bool
timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
{
 using namespace chrono;
 unique_lock<mutex> __lk(__m_);
 bool no_timeout = _Clock::now() < __t;
 while (no_timeout && __locked_)
 no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
 if (!__locked_)
 {
 __locked_ = true;
 return true;
 }
 return false;
}

class _LIBCPP_TYPE_VIS recursive_timed_mutex
{
 mutex __m_;
 condition_variable __cv_;
 size_t __count_;
 __libcpp_thread_id __id_;
public:
 recursive_timed_mutex();
 ~recursive_timed_mutex();

private:
 recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
 recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;

public:
 void lock();
 bool try_lock() _NOEXCEPT;
 template <class _Rep, class _Period>
 _LIBCPP_INLINE_VISIBILITY
 bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
 {return try_lock_until(chrono::steady_clock::now() + __d);}
 template <class _Clock, class _Duration>
 bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
 void unlock() _NOEXCEPT;
};

template <class _Clock, class _Duration>
bool
recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
{
 using namespace chrono;
 __libcpp_thread_id __id = __libcpp_thread_get_current_id();
 unique_lock<mutex> lk(__m_);
 if (__libcpp_thread_id_equal(__id, __id_))
 {
 if (__count_ == numeric_limits<size_t>::max())
 return false;
 ++__count_;
 return true;
 }
 bool no_timeout = _Clock::now() < __t;
 while (no_timeout && __count_ != 0)
 no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
 if (__count_ == 0)
 {
 __count_ = 1;
 __id_ = __id;
 return true;
 }
 return false;
}

template <class _L0, class _L1>
int
try_lock(_L0& __l0, _L1& __l1)
{
 unique_lock<_L0> __u0(__l0, try_to_lock);
 if (__u0.owns_lock())
 {
 if (__l1.try_lock())
 {
 __u0.release();
 return -1;
 }
 else
 return 1;
 }
 return 0;
}

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <class _L0, class _L1, class _L2, class... _L3>
int
try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
{
 int __r = 0;
 unique_lock<_L0> __u0(__l0, try_to_lock);
 if (__u0.owns_lock())
 {
 __r = try_lock(__l1, __l2, __l3...);
 if (__r == -1)
 __u0.release();
 else
 ++__r;
 }
 return __r;
}

#endif // _LIBCPP_HAS_NO_VARIADICS

template <class _L0, class _L1>
void
lock(_L0& __l0, _L1& __l1)
{
 while (true)
 {
 {
 unique_lock<_L0> __u0(__l0);
 if (__l1.try_lock())
 {
 __u0.release();
 break;
 }
 }
 __libcpp_thread_yield();
 {
 unique_lock<_L1> __u1(__l1);
 if (__l0.try_lock())
 {
 __u1.release();
 break;
 }
 }
 __libcpp_thread_yield();
 }
}

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <class _L0, class _L1, class _L2, class ..._L3>
void
__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
{
 while (true)
 {
 switch (__i)
 {
 case 0:
 {
 unique_lock<_L0> __u0(__l0);
 __i = try_lock(__l1, __l2, __l3...);
 if (__i == -1)
 {
 __u0.release();
 return;
 }
 }
 ++__i;
 __libcpp_thread_yield();
 break;
 case 1:
 {
 unique_lock<_L1> __u1(__l1);
 __i = try_lock(__l2, __l3..., __l0);
 if (__i == -1)
 {
 __u1.release();
 return;
 }
 }
 if (__i == sizeof...(_L3) + 1)
 __i = 0;
 else
 __i += 2;
 __libcpp_thread_yield();
 break;
 default:
 __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
 return;
 }
 }
}

template <class _L0, class _L1, class _L2, class ..._L3>
inline _LIBCPP_INLINE_VISIBILITY
void
lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
{
 __lock_first(0, __l0, __l1, __l2, __l3...);
}

template <class _L0>
inline _LIBCPP_INLINE_VISIBILITY
void __unlock(_L0& __l0) {
 __l0.unlock();
}

template <class _L0, class _L1>
inline _LIBCPP_INLINE_VISIBILITY
void __unlock(_L0& __l0, _L1& __l1) {
 __l0.unlock();
 __l1.unlock();
}

template <class _L0, class _L1, class _L2, class ..._L3>
inline _LIBCPP_INLINE_VISIBILITY
void __unlock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3) {
 __l0.unlock();
 __l1.unlock();
 _VSTD::__unlock(__l2, __l3...);
}

#endif // _LIBCPP_HAS_NO_VARIADICS

#endif // !_LIBCPP_HAS_NO_THREADS

struct _LIBCPP_TYPE_VIS_ONLY once_flag;

#ifndef _LIBCPP_HAS_NO_VARIADICS

template<class _Callable, class... _Args>
_LIBCPP_INLINE_VISIBILITY
void call_once(once_flag&, _Callable&&, _Args&&...);

#else // _LIBCPP_HAS_NO_VARIADICS

template<class _Callable>
_LIBCPP_INLINE_VISIBILITY
void call_once(once_flag&, _Callable&);

template<class _Callable>
_LIBCPP_INLINE_VISIBILITY
void call_once(once_flag&, const _Callable&);

#endif // _LIBCPP_HAS_NO_VARIADICS

struct _LIBCPP_TYPE_VIS_ONLY once_flag
{
 _LIBCPP_INLINE_VISIBILITY
 _LIBCPP_CONSTEXPR
 once_flag() _NOEXCEPT : __state_(0) {}

private:
 once_flag(const once_flag&); // = delete;
 once_flag& operator=(const once_flag&); // = delete;

 unsigned long __state_;

#ifndef _LIBCPP_HAS_NO_VARIADICS
 template<class _Callable, class... _Args>
 friend
 void call_once(once_flag&, _Callable&&, _Args&&...);
#else // _LIBCPP_HAS_NO_VARIADICS
 template<class _Callable>
 friend
 void call_once(once_flag&, _Callable&);

 template<class _Callable>
 friend
 void call_once(once_flag&, const _Callable&);
#endif // _LIBCPP_HAS_NO_VARIADICS
};

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <class _Fp>
class __call_once_param
{
 _Fp& __f_;
public:
 _LIBCPP_INLINE_VISIBILITY
 explicit __call_once_param(_Fp& __f) : __f_(__f) {}

 _LIBCPP_INLINE_VISIBILITY
 void operator()()
 {
 typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
 __execute(_Index());
 }

private:
 template <size_t ..._Indices>
 _LIBCPP_INLINE_VISIBILITY
 void __execute(__tuple_indices<_Indices...>)
 {
 __invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
 }
};

#else

template <class _Fp>
class __call_once_param
{
 _Fp& __f_;
public:
 _LIBCPP_INLINE_VISIBILITY
 explicit __call_once_param(_Fp& __f) : __f_(__f) {}

 _LIBCPP_INLINE_VISIBILITY
 void operator()()
 {
 __f_();
 }
};

#endif

template <class _Fp>
void
__call_once_proxy(void* __vp)
{
 __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
 (*__p)();
}

_LIBCPP_FUNC_VIS void __call_once(volatile unsigned long&, void*, void(*)(void*));

#ifndef _LIBCPP_HAS_NO_VARIADICS

template<class _Callable, class... _Args>
inline _LIBCPP_INLINE_VISIBILITY
void
call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
{
 if (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
 {
 typedef tuple<_Callable&&, _Args&&...> _Gp;
 _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
 __call_once_param<_Gp> __p(__f);
 __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
 }
}

#else // _LIBCPP_HAS_NO_VARIADICS

template<class _Callable>
inline _LIBCPP_INLINE_VISIBILITY
void
call_once(once_flag& __flag, _Callable& __func)
{
 if (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
 {
 __call_once_param<_Callable> __p(__func);
 __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
 }
}

template<class _Callable>
inline _LIBCPP_INLINE_VISIBILITY
void
call_once(once_flag& __flag, const _Callable& __func)
{
 if (__flag.__state_ != ~0ul)
 {
 __call_once_param<const _Callable> __p(__func);
 __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
 }
}

#endif // _LIBCPP_HAS_NO_VARIADICS


#if defined(_LIBCPP_ABI_VARIADIC_LOCK_GUARD) \
 && !defined(_LIBCPP_CXX03_LANG)
template <>
class _LIBCPP_TYPE_VIS_ONLY lock_guard<> {
public:
 explicit lock_guard() {}
 ~lock_guard() = default;

 _LIBCPP_INLINE_VISIBILITY
 explicit lock_guard(adopt_lock_t) {}

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

template <class ..._MArgs>
class _LIBCPP_TYPE_VIS_ONLY lock_guard
{
 static_assert(sizeof...(_MArgs) >= 2, "At least 2 lock types required");
 typedef tuple<_MArgs&...> _MutexTuple;

public:
 _LIBCPP_INLINE_VISIBILITY
 explicit lock_guard(_MArgs&... __margs)
 : __t_(__margs...)
 {
 _VSTD::lock(__margs...);
 }

 _LIBCPP_INLINE_VISIBILITY
 lock_guard(_MArgs&... __margs, adopt_lock_t)
 : __t_(__margs...)
 {
 }

 _LIBCPP_INLINE_VISIBILITY
 ~lock_guard() {
 typedef typename __make_tuple_indices<sizeof...(_MArgs)>::type _Indices;
 __unlock_unpack(_Indices{}, __t_);
 }

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

private:
 template <size_t ..._Indx>
 _LIBCPP_INLINE_VISIBILITY
 static void __unlock_unpack(__tuple_indices<_Indx...>, _MutexTuple& __mt) {
 _VSTD::__unlock(_VSTD::get<_Indx>(__mt)...);
 }

 _MutexTuple __t_;
};

#endif // _LIBCPP_ABI_VARIADIC_LOCK_GUARD

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_MUTEX