xref: /llvm-project-15.0.7/libcxx/include/condition_variable (revision b48c5010)

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_CONDITION_VARIABLE
#define _LIBCPP_CONDITION_VARIABLE

/*
    condition_variable synopsis

namespace std
{

enum class cv_status { no_timeout, timeout };

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

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

    void notify_one() noexcept;
    void notify_all() noexcept;

    void wait(unique_lock<mutex>& lock);
    template <class Predicate>
        void wait(unique_lock<mutex>& lock, Predicate pred);

    template <class Clock, class Duration>
        cv_status
        wait_until(unique_lock<mutex>& lock,
                   const chrono::time_point<Clock, Duration>& abs_time);

    template <class Clock, class Duration, class Predicate>
        bool
        wait_until(unique_lock<mutex>& lock,
                   const chrono::time_point<Clock, Duration>& abs_time,
                   Predicate pred);

    template <class Rep, class Period>
        cv_status
        wait_for(unique_lock<mutex>& lock,
                 const chrono::duration<Rep, Period>& rel_time);

    template <class Rep, class Period, class Predicate>
        bool
        wait_for(unique_lock<mutex>& lock,
                 const chrono::duration<Rep, Period>& rel_time,
                 Predicate pred);

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

void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk);

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

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

    void notify_one() noexcept;
    void notify_all() noexcept;

    template <class Lock>
        void wait(Lock& lock);
    template <class Lock, class Predicate>
        void wait(Lock& lock, Predicate pred);

    template <class Lock, class Clock, class Duration>
        cv_status
        wait_until(Lock& lock,
                   const chrono::time_point<Clock, Duration>& abs_time);

    template <class Lock, class Clock, class Duration, class Predicate>
        bool
        wait_until(Lock& lock,
                   const chrono::time_point<Clock, Duration>& abs_time,
                   Predicate pred);

    template <class Lock, class Rep, class Period>
        cv_status
        wait_for(Lock& lock,
                 const chrono::duration<Rep, Period>& rel_time);

    template <class Lock, class Rep, class Period, class Predicate>
        bool
        wait_for(Lock& lock,
                 const chrono::duration<Rep, Period>& rel_time,
                 Predicate pred);
};

}  // std

*/

#include <__assert> // all public C++ headers provide the assertion handler
#include <__config>
#include <__mutex_base>
#include <memory>
#include <version>

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

#ifndef _LIBCPP_HAS_NO_THREADS

_LIBCPP_BEGIN_NAMESPACE_STD

class _LIBCPP_TYPE_VIS condition_variable_any
{
    condition_variable __cv_;
    shared_ptr<mutex>  __mut_;
public:
    _LIBCPP_INLINE_VISIBILITY
    condition_variable_any();

    _LIBCPP_INLINE_VISIBILITY
    void notify_one() _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    void notify_all() _NOEXCEPT;

    template <class _Lock>
        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
        void wait(_Lock& __lock);
    template <class _Lock, class _Predicate>
        _LIBCPP_INLINE_VISIBILITY
        void wait(_Lock& __lock, _Predicate __pred);

    template <class _Lock, class _Clock, class _Duration>
        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
        cv_status
        wait_until(_Lock& __lock,
                   const chrono::time_point<_Clock, _Duration>& __t);

    template <class _Lock, class _Clock, class _Duration, class _Predicate>
        bool
        _LIBCPP_INLINE_VISIBILITY
        wait_until(_Lock& __lock,
                   const chrono::time_point<_Clock, _Duration>& __t,
                   _Predicate __pred);

    template <class _Lock, class _Rep, class _Period>
        cv_status
        _LIBCPP_INLINE_VISIBILITY
        wait_for(_Lock& __lock,
                 const chrono::duration<_Rep, _Period>& __d);

    template <class _Lock, class _Rep, class _Period, class _Predicate>
        bool
        _LIBCPP_INLINE_VISIBILITY
        wait_for(_Lock& __lock,
                 const chrono::duration<_Rep, _Period>& __d,
                 _Predicate __pred);
};

inline
condition_variable_any::condition_variable_any()
    : __mut_(make_shared<mutex>()) {}

inline
void
condition_variable_any::notify_one() _NOEXCEPT
{
    {lock_guard<mutex> __lx(*__mut_);}
    __cv_.notify_one();
}

inline
void
condition_variable_any::notify_all() _NOEXCEPT
{
    {lock_guard<mutex> __lx(*__mut_);}
    __cv_.notify_all();
}

struct __lock_external
{
    template <class _Lock>
    void operator()(_Lock* __m) {__m->lock();}
};

template <class _Lock>
void
condition_variable_any::wait(_Lock& __lock)
{
    shared_ptr<mutex> __mut = __mut_;
    unique_lock<mutex> __lk(*__mut);
    __lock.unlock();
    unique_ptr<_Lock, __lock_external> __lxx(&__lock);
    lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock);
    __cv_.wait(__lk);
}  // __mut_.unlock(), __lock.lock()

template <class _Lock, class _Predicate>
inline
void
condition_variable_any::wait(_Lock& __lock, _Predicate __pred)
{
    while (!__pred())
        wait(__lock);
}

template <class _Lock, class _Clock, class _Duration>
cv_status
condition_variable_any::wait_until(_Lock& __lock,
                                   const chrono::time_point<_Clock, _Duration>& __t)
{
    shared_ptr<mutex> __mut = __mut_;
    unique_lock<mutex> __lk(*__mut);
    __lock.unlock();
    unique_ptr<_Lock, __lock_external> __lxx(&__lock);
    lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock);
    return __cv_.wait_until(__lk, __t);
}  // __mut_.unlock(), __lock.lock()

template <class _Lock, class _Clock, class _Duration, class _Predicate>
inline
bool
condition_variable_any::wait_until(_Lock& __lock,
                                   const chrono::time_point<_Clock, _Duration>& __t,
                                   _Predicate __pred)
{
    while (!__pred())
        if (wait_until(__lock, __t) == cv_status::timeout)
            return __pred();
    return true;
}

template <class _Lock, class _Rep, class _Period>
inline
cv_status
condition_variable_any::wait_for(_Lock& __lock,
                                 const chrono::duration<_Rep, _Period>& __d)
{
    return wait_until(__lock, chrono::steady_clock::now() + __d);
}

template <class _Lock, class _Rep, class _Period, class _Predicate>
inline
bool
condition_variable_any::wait_for(_Lock& __lock,
                                 const chrono::duration<_Rep, _Period>& __d,
                                 _Predicate __pred)
{
    return wait_until(__lock, chrono::steady_clock::now() + __d,
                      _VSTD::move(__pred));
}

_LIBCPP_FUNC_VIS
void notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);

_LIBCPP_END_NAMESPACE_STD

#endif // !_LIBCPP_HAS_NO_THREADS

#endif // _LIBCPP_CONDITION_VARIABLE