include/thread

// -*- C++ -*-
//===--------------------------- thread -----------------------------------===//
//
// 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_THREAD
#define _LIBCPP_THREAD

/*

 thread synopsis

#define __STDCPP_THREADS__ __cplusplus

namespace std
{

class thread
{
public:
 class id;
 typedef pthread_t native_handle_type;

 thread() noexcept;
 template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
 ~thread();

 thread(const thread&) = delete;
 thread(thread&& t) noexcept;

 thread& operator=(const thread&) = delete;
 thread& operator=(thread&& t) noexcept;

 void swap(thread& t) noexcept;

 bool joinable() const noexcept;
 void join();
 void detach();
 id get_id() const noexcept;
 native_handle_type native_handle();

 static unsigned hardware_concurrency() noexcept;
};

void swap(thread& x, thread& y) noexcept;

class thread::id
{
public:
 id() noexcept;
};

bool operator==(thread::id x, thread::id y) noexcept;
bool operator!=(thread::id x, thread::id y) noexcept;
bool operator< (thread::id x, thread::id y) noexcept;
bool operator<=(thread::id x, thread::id y) noexcept;
bool operator> (thread::id x, thread::id y) noexcept;
bool operator>=(thread::id x, thread::id y) noexcept;

template<class charT, class traits>
basic_ostream<charT, traits>&
operator<<(basic_ostream<charT, traits>& out, thread::id id);

namespace this_thread
{

thread::id get_id() noexcept;

void yield() noexcept;

template <class Clock, class Duration>
void sleep_until(const chrono::time_point<Clock, Duration>& abs_time);

template <class Rep, class Period>
void sleep_for(const chrono::duration<Rep, Period>& rel_time);

} // this_thread

} // std

*/

#include <__config>
#include <iosfwd>
#include <__functional_base>
#include <type_traits>
#include <cstddef>
#include <functional>
#include <memory>
#include <system_error>
#include <chrono>
#include <__mutex_base>
#ifndef _LIBCPP_HAS_NO_VARIADICS
#include <tuple>
#endif
#include <pthread.h>
#include <sched.h>

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

#define __STDCPP_THREADS__ __cplusplus

#ifdef _LIBCPP_HAS_NO_THREADS
#error <thread> is not supported on this single threaded system
#else // !_LIBCPP_HAS_NO_THREADS

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Tp> class __thread_specific_ptr;
class _LIBCPP_TYPE_VIS __thread_struct;
class _LIBCPP_HIDDEN __thread_struct_imp;
class __assoc_sub_state;

_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();

class _LIBCPP_TYPE_VIS __thread_struct
{
 __thread_struct_imp* __p_;

 __thread_struct(const __thread_struct&);
 __thread_struct& operator=(const __thread_struct&);
public:
 __thread_struct();
 ~__thread_struct();

 void notify_all_at_thread_exit(condition_variable*, mutex*);
 void __make_ready_at_thread_exit(__assoc_sub_state*);
};

template <class _Tp>
class __thread_specific_ptr
{
 pthread_key_t __key_;

 // Only __thread_local_data() may construct a __thread_specific_ptr
 // and only with _Tp == __thread_struct.
 static_assert((is_same<_Tp, __thread_struct>::value), "");
 __thread_specific_ptr();
 friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();

 __thread_specific_ptr(const __thread_specific_ptr&);
 __thread_specific_ptr& operator=(const __thread_specific_ptr&);

 static void __at_thread_exit(void*);
public:
 typedef _Tp* pointer;

 ~__thread_specific_ptr();

 _LIBCPP_INLINE_VISIBILITY
 pointer get() const {return static_cast<_Tp*>(pthread_getspecific(__key_));}
 _LIBCPP_INLINE_VISIBILITY
 pointer operator*() const {return *get();}
 _LIBCPP_INLINE_VISIBILITY
 pointer operator->() const {return get();}
 pointer release();
 void reset(pointer __p = nullptr);
};

template <class _Tp>
void
__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
{
 delete static_cast<pointer>(__p);
}

template <class _Tp>
__thread_specific_ptr<_Tp>::__thread_specific_ptr()
{
 int __ec = pthread_key_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
#ifndef _LIBCPP_NO_EXCEPTIONS
 if (__ec)
 throw system_error(error_code(__ec, system_category()),
 "__thread_specific_ptr construction failed");
#endif
}

template <class _Tp>
__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
{
 // __thread_specific_ptr is only created with a static storage duration
 // so this destructor is only invoked during program termination. Invoking
 // pthread_key_delete(__key_) may prevent other threads from deleting their
 // thread local data. For this reason we leak the key.
}

template <class _Tp>
typename __thread_specific_ptr<_Tp>::pointer
__thread_specific_ptr<_Tp>::release()
{
 pointer __p = get();
 pthread_setspecific(__key_, 0);
 return __p;
}

template <class _Tp>
void
__thread_specific_ptr<_Tp>::reset(pointer __p)
{
 pointer __p_old = get();
 pthread_setspecific(__key_, __p);
 delete __p_old;
}

class _LIBCPP_TYPE_VIS thread;
class _LIBCPP_TYPE_VIS __thread_id;

namespace this_thread
{

_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;

} // this_thread

template<> struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;

class _LIBCPP_TYPE_VIS_ONLY __thread_id
{
 // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
 // NULL is the no-thread value on Darwin. Someone needs to check
 // on other platforms. We assume 0 works everywhere for now.
 pthread_t __id_;

public:
 _LIBCPP_INLINE_VISIBILITY
 __thread_id() _NOEXCEPT : __id_(0) {}

 friend _LIBCPP_INLINE_VISIBILITY
 bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
 {return __x.__id_ == __y.__id_;}
 friend _LIBCPP_INLINE_VISIBILITY
 bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
 {return !(__x == __y);}
 friend _LIBCPP_INLINE_VISIBILITY
 bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
 {return __x.__id_ < __y.__id_;}
 friend _LIBCPP_INLINE_VISIBILITY
 bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
 {return !(__y < __x);}
 friend _LIBCPP_INLINE_VISIBILITY
 bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
 {return __y < __x ;}
 friend _LIBCPP_INLINE_VISIBILITY
 bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
 {return !(__x < __y);}

 template<class _CharT, class _Traits>
 friend
 _LIBCPP_INLINE_VISIBILITY
 basic_ostream<_CharT, _Traits>&
 operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
 {return __os << __id.__id_;}

private:
 _LIBCPP_INLINE_VISIBILITY
 __thread_id(pthread_t __id) : __id_(__id) {}

 friend __thread_id this_thread::get_id() _NOEXCEPT;
 friend class _LIBCPP_TYPE_VIS thread;
 friend struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;
};

template<>
struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>
 : public unary_function<__thread_id, size_t>
{
 _LIBCPP_INLINE_VISIBILITY
 size_t operator()(__thread_id __v) const
 {
 return hash<pthread_t>()(__v.__id_);
 }
};

namespace this_thread
{

inline _LIBCPP_INLINE_VISIBILITY
__thread_id
get_id() _NOEXCEPT
{
 return pthread_self();
}

} // this_thread

class _LIBCPP_TYPE_VIS thread
{
 pthread_t __t_;

 thread(const thread&);
 thread& operator=(const thread&);
public:
 typedef __thread_id id;
 typedef pthread_t native_handle_type;

 _LIBCPP_INLINE_VISIBILITY
 thread() _NOEXCEPT : __t_(0) {}
#ifndef _LIBCPP_HAS_NO_VARIADICS
 template <class _Fp, class ..._Args,
 class = typename enable_if
 <
 !is_same<typename decay<_Fp>::type, thread>::value
 >::type
 >
 explicit thread(_Fp&& __f, _Args&&... __args);
#else // _LIBCPP_HAS_NO_VARIADICS
 template <class _Fp> explicit thread(_Fp __f);
#endif
 ~thread();

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
 _LIBCPP_INLINE_VISIBILITY
 thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = 0;}
 thread& operator=(thread&& __t) _NOEXCEPT;
#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES

 _LIBCPP_INLINE_VISIBILITY
 void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}

 _LIBCPP_INLINE_VISIBILITY
 bool joinable() const _NOEXCEPT {return __t_ != 0;}
 void join();
 void detach();
 _LIBCPP_INLINE_VISIBILITY
 id get_id() const _NOEXCEPT {return __t_;}
 _LIBCPP_INLINE_VISIBILITY
 native_handle_type native_handle() _NOEXCEPT {return __t_;}

 static unsigned hardware_concurrency() _NOEXCEPT;
};

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <class _Fp, class ..._Args, size_t ..._Indices>
inline _LIBCPP_INLINE_VISIBILITY
void
__thread_execute(tuple<_Fp, _Args...>& __t, __tuple_indices<_Indices...>)
{
 __invoke(_VSTD::move(_VSTD::get<0>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
}

template <class _Fp>
void*
__thread_proxy(void* __vp)
{
 __thread_local_data().reset(new __thread_struct);
 std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
 typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
 __thread_execute(*__p, _Index());
 return nullptr;
}

template <class _Fp, class ..._Args,
 class
 >
thread::thread(_Fp&& __f, _Args&&... __args)
{
 typedef tuple<typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
 _VSTD::unique_ptr<_Gp> __p(new _Gp(__decay_copy(_VSTD::forward<_Fp>(__f)),
 __decay_copy(_VSTD::forward<_Args>(__args))...));
 int __ec = pthread_create(&__t_, 0, &__thread_proxy<_Gp>, __p.get());
 if (__ec == 0)
 __p.release();
 else
 __throw_system_error(__ec, "thread constructor failed");
}

#else // _LIBCPP_HAS_NO_VARIADICS

template <class _Fp>
void*
__thread_proxy(void* __vp)
{
 __thread_local_data().reset(new __thread_struct);
 std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
 (*__p)();
 return nullptr;
}

template <class _Fp>
thread::thread(_Fp __f)
{
 std::unique_ptr<_Fp> __p(new _Fp(__f));
 int __ec = pthread_create(&__t_, 0, &__thread_proxy<_Fp>, __p.get());
 if (__ec == 0)
 __p.release();
 else
 __throw_system_error(__ec, "thread constructor failed");
}

#endif // _LIBCPP_HAS_NO_VARIADICS

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

inline _LIBCPP_INLINE_VISIBILITY
thread&
thread::operator=(thread&& __t) _NOEXCEPT
{
 if (__t_ != 0)
 terminate();
 __t_ = __t.__t_;
 __t.__t_ = 0;
 return *this;
}

#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES

inline _LIBCPP_INLINE_VISIBILITY
void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}

namespace this_thread
{

_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& ns);

template <class _Rep, class _Period>
void
sleep_for(const chrono::duration<_Rep, _Period>& __d)
{
 using namespace chrono;
 if (__d > duration<_Rep, _Period>::zero())
 {
 _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
 nanoseconds __ns;
 if (__d < _Max)
 {
 __ns = duration_cast<nanoseconds>(__d);
 if (__ns < __d)
 ++__ns;
 }
 else
 __ns = nanoseconds::max();
 sleep_for(__ns);
 }
}

template <class _Clock, class _Duration>
void
sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
{
 using namespace chrono;
 mutex __mut;
 condition_variable __cv;
 unique_lock<mutex> __lk(__mut);
 while (_Clock::now() < __t)
 __cv.wait_until(__lk, __t);
}

template <class _Duration>
inline _LIBCPP_INLINE_VISIBILITY
void
sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
{
 using namespace chrono;
 sleep_for(__t - steady_clock::now());
}

inline _LIBCPP_INLINE_VISIBILITY
void yield() _NOEXCEPT {sched_yield();}

} // this_thread

_LIBCPP_END_NAMESPACE_STD

#endif // !_LIBCPP_HAS_NO_THREADS

#endif // _LIBCPP_THREAD