llvm-project/libcxx/include/__cxx03/mutex

// -*- 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___CXX03_MUTEX
#define _LIBCPP___CXX03_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 { explicit defer_lock_t() = default; };
struct try_to_lock_t { explicit try_to_lock_t() = default; };
struct adopt_lock_t { explicit adopt_lock_t() = default; };

inline constexpr defer_lock_t  defer_lock{};
inline constexpr try_to_lock_t try_to_lock{};
inline 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>
class scoped_lock // C++17
{
public:
    using mutex_type = Mutex;  // Only if sizeof...(MutexTypes) == 1

    explicit scoped_lock(MutexTypes&... m);
    scoped_lock(adopt_lock_t, MutexTypes&... m);
    ~scoped_lock();
    scoped_lock(scoped_lock const&) = delete;
    scoped_lock& operator=(scoped_lock 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 <__cxx03/__chrono/steady_clock.h>
#include <__cxx03/__chrono/time_point.h>
#include <__cxx03/__condition_variable/condition_variable.h>
#include <__cxx03/__config>
#include <__cxx03/__memory/shared_ptr.h>
#include <__cxx03/__mutex/lock_guard.h>
#include <__cxx03/__mutex/mutex.h>
#include <__cxx03/__mutex/once_flag.h>
#include <__cxx03/__mutex/tag_types.h>
#include <__cxx03/__mutex/unique_lock.h>
#include <__cxx03/__thread/id.h>
#include <__cxx03/__thread/support.h>
#include <__cxx03/__utility/forward.h>
#include <__cxx03/cstddef>
#include <__cxx03/limits>
#include <__cxx03/version>

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

_LIBCPP_PUSH_MACROS
#include <__cxx03/__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

#ifndef _LIBCPP_HAS_NO_THREADS

class _LIBCPP_EXPORTED_FROM_ABI recursive_mutex {
  __libcpp_recursive_mutex_t __m_;

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() _NOEXCEPT;

  typedef __libcpp_recursive_mutex_t* native_handle_type;

  _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return &__m_; }
};

class _LIBCPP_EXPORTED_FROM_ABI timed_mutex {
  mutex __m_;
  condition_variable __cv_;
  bool __locked_;

public:
  timed_mutex();
  ~timed_mutex();

  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_HIDE_FROM_ABI bool try_lock_for(const chrono::duration<_Rep, _Period>& __d) {
    return try_lock_until(chrono::steady_clock::now() + __d);
  }
  template <class _Clock, class _Duration>
  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS 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_EXPORTED_FROM_ABI recursive_timed_mutex {
  mutex __m_;
  condition_variable __cv_;
  size_t __count_;
  __thread_id __id_;

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>
  _LIBCPP_HIDE_FROM_ABI bool try_lock_for(const chrono::duration<_Rep, _Period>& __d) {
    return try_lock_until(chrono::steady_clock::now() + __d);
  }
  template <class _Clock, class _Duration>
  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS 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;
  __thread_id __id = this_thread::get_id();
  unique_lock<mutex> __lk(__m_);
  if (__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>
_LIBCPP_HIDE_FROM_ABI int try_lock(_L0& __l0, _L1& __l1) {
  unique_lock<_L0> __u0(__l0, try_to_lock_t());
  if (__u0.owns_lock()) {
    if (__l1.try_lock()) {
      __u0.release();
      return -1;
    } else
      return 1;
  }
  return 0;
}

template <class _L0, class _L1>
_LIBCPP_HIDE_FROM_ABI 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();
  }
}
#endif   // !_LIBCPP_HAS_NO_THREADS

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES)
#  include <__cxx03/atomic>
#  include <__cxx03/cstdlib>
#  include <__cxx03/cstring>
#  include <__cxx03/ctime>
#  include <__cxx03/iosfwd>
#  include <__cxx03/new>
#  include <__cxx03/stdexcept>
#  include <__cxx03/system_error>
#  include <__cxx03/type_traits>
#  include <__cxx03/typeinfo>
#endif

#endif // _LIBCPP___CXX03_MUTEX