xref: /freebsd-12.1/contrib/libc++/include/thread (revision fc3777bd) 
1// -*- C++ -*-
2//===--------------------------- thread -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_THREAD
12#define _LIBCPP_THREAD
13
14/*
15
16    thread synopsis
17
18#define __STDCPP_THREADS__ __cplusplus
19
20namespace std
21{
22
23class thread
24{
25public:
26    class id;
27    typedef pthread_t native_handle_type;
28
29    thread() noexcept;
30    template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
31    ~thread();
32
33    thread(const thread&) = delete;
34    thread(thread&& t) noexcept;
35
36    thread& operator=(const thread&) = delete;
37    thread& operator=(thread&& t) noexcept;
38
39    void swap(thread& t) noexcept;
40
41    bool joinable() const noexcept;
42    void join();
43    void detach();
44    id get_id() const noexcept;
45    native_handle_type native_handle();
46
47    static unsigned hardware_concurrency() noexcept;
48};
49
50void swap(thread& x, thread& y) noexcept;
51
52class thread::id
53{
54public:
55    id() noexcept;
56};
57
58bool operator==(thread::id x, thread::id y) noexcept;
59bool operator!=(thread::id x, thread::id y) noexcept;
60bool operator< (thread::id x, thread::id y) noexcept;
61bool operator<=(thread::id x, thread::id y) noexcept;
62bool operator> (thread::id x, thread::id y) noexcept;
63bool operator>=(thread::id x, thread::id y) noexcept;
64
65template<class charT, class traits>
66basic_ostream<charT, traits>&
67operator<<(basic_ostream<charT, traits>& out, thread::id id);
68
69namespace this_thread
70{
71
72thread::id get_id() noexcept;
73
74void yield() noexcept;
75
76template <class Clock, class Duration>
77void sleep_until(const chrono::time_point<Clock, Duration>& abs_time);
78
79template <class Rep, class Period>
80void sleep_for(const chrono::duration<Rep, Period>& rel_time);
81
82}  // this_thread
83
84}  // std
85
86*/
87
88#include <__config>
89#include <iosfwd>
90#include <__functional_base>
91#include <type_traits>
92#include <cstddef>
93#include <functional>
94#include <memory>
95#include <system_error>
96#include <chrono>
97#include <__mutex_base>
98#ifndef _LIBCPP_CXX03_LANG
99#include <tuple>
100#endif
101#include <__threading_support>
102#include <__debug>
103
104#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
105#pragma GCC system_header
106#endif
107
108_LIBCPP_PUSH_MACROS
109#include <__undef_macros>
110
111#define __STDCPP_THREADS__ __cplusplus
112
113#ifdef _LIBCPP_HAS_NO_THREADS
114#error <thread> is not supported on this single threaded system
115#else // !_LIBCPP_HAS_NO_THREADS
116
117_LIBCPP_BEGIN_NAMESPACE_STD
118
119template <class _Tp> class __thread_specific_ptr;
120class _LIBCPP_TYPE_VIS __thread_struct;
121class _LIBCPP_HIDDEN __thread_struct_imp;
122class __assoc_sub_state;
123
124_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
125
126class _LIBCPP_TYPE_VIS __thread_struct
127{
128    __thread_struct_imp* __p_;
129
130    __thread_struct(const __thread_struct&);
131    __thread_struct& operator=(const __thread_struct&);
132public:
133    __thread_struct();
134    ~__thread_struct();
135
136    void notify_all_at_thread_exit(condition_variable*, mutex*);
137    void __make_ready_at_thread_exit(__assoc_sub_state*);
138};
139
140template <class _Tp>
141class __thread_specific_ptr
142{
143    __libcpp_tls_key __key_;
144
145     // Only __thread_local_data() may construct a __thread_specific_ptr
146     // and only with _Tp == __thread_struct.
147    static_assert((is_same<_Tp, __thread_struct>::value), "");
148    __thread_specific_ptr();
149    friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
150
151    __thread_specific_ptr(const __thread_specific_ptr&);
152    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
153
154    _LIBCPP_HIDDEN static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
155
156public:
157    typedef _Tp* pointer;
158
159    ~__thread_specific_ptr();
160
161    _LIBCPP_INLINE_VISIBILITY
162    pointer get() const {return static_cast<_Tp*>(__libcpp_tls_get(__key_));}
163    _LIBCPP_INLINE_VISIBILITY
164    pointer operator*() const {return *get();}
165    _LIBCPP_INLINE_VISIBILITY
166    pointer operator->() const {return get();}
167    void set_pointer(pointer __p);
168};
169
170template <class _Tp>
171void _LIBCPP_TLS_DESTRUCTOR_CC
172__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
173{
174    delete static_cast<pointer>(__p);
175}
176
177template <class _Tp>
178__thread_specific_ptr<_Tp>::__thread_specific_ptr()
179{
180  int __ec =
181      __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
182  if (__ec)
183    __throw_system_error(__ec, "__thread_specific_ptr construction failed");
184}
185
186template <class _Tp>
187__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
188{
189    // __thread_specific_ptr is only created with a static storage duration
190    // so this destructor is only invoked during program termination. Invoking
191    // pthread_key_delete(__key_) may prevent other threads from deleting their
192    // thread local data. For this reason we leak the key.
193}
194
195template <class _Tp>
196void
197__thread_specific_ptr<_Tp>::set_pointer(pointer __p)
198{
199    _LIBCPP_ASSERT(get() == nullptr,
200                   "Attempting to overwrite thread local data");
201    __libcpp_tls_set(__key_, __p);
202}
203
204template<>
205struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>
206    : public unary_function<__thread_id, size_t>
207{
208    _LIBCPP_INLINE_VISIBILITY
209    size_t operator()(__thread_id __v) const _NOEXCEPT
210    {
211        return hash<__libcpp_thread_id>()(__v.__id_);
212    }
213};
214
215template<class _CharT, class _Traits>
216_LIBCPP_INLINE_VISIBILITY
217basic_ostream<_CharT, _Traits>&
218operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
219{return __os << __id.__id_;}
220
221class _LIBCPP_TYPE_VIS thread
222{
223    __libcpp_thread_t __t_;
224
225    thread(const thread&);
226    thread& operator=(const thread&);
227public:
228    typedef __thread_id id;
229    typedef __libcpp_thread_t native_handle_type;
230
231    _LIBCPP_INLINE_VISIBILITY
232    thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
233#ifndef _LIBCPP_CXX03_LANG
234    template <class _Fp, class ..._Args,
235              class = typename enable_if
236              <
237                   !is_same<typename __uncvref<_Fp>::type, thread>::value
238              >::type
239             >
240        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
241        explicit thread(_Fp&& __f, _Args&&... __args);
242#else  // _LIBCPP_CXX03_LANG
243    template <class _Fp>
244    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
245    explicit thread(_Fp __f);
246#endif
247    ~thread();
248
249#ifndef _LIBCPP_CXX03_LANG
250    _LIBCPP_INLINE_VISIBILITY
251    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = _LIBCPP_NULL_THREAD;}
252    _LIBCPP_INLINE_VISIBILITY
253    thread& operator=(thread&& __t) _NOEXCEPT;
254#endif  // _LIBCPP_CXX03_LANG
255
256    _LIBCPP_INLINE_VISIBILITY
257    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
258
259    _LIBCPP_INLINE_VISIBILITY
260    bool joinable() const _NOEXCEPT {return !__libcpp_thread_isnull(&__t_);}
261    void join();
262    void detach();
263    _LIBCPP_INLINE_VISIBILITY
264    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
265    _LIBCPP_INLINE_VISIBILITY
266    native_handle_type native_handle() _NOEXCEPT {return __t_;}
267
268    static unsigned hardware_concurrency() _NOEXCEPT;
269};
270
271#ifndef _LIBCPP_CXX03_LANG
272
273template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
274inline _LIBCPP_INLINE_VISIBILITY
275void
276__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
277{
278    __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
279}
280
281template <class _Fp>
282void* __thread_proxy(void* __vp)
283{
284    // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
285    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
286    __thread_local_data().set_pointer(_VSTD::get<0>(*__p).release());
287    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
288    __thread_execute(*__p, _Index());
289    return nullptr;
290}
291
292template <class _Fp, class ..._Args,
293          class
294         >
295thread::thread(_Fp&& __f, _Args&&... __args)
296{
297    typedef unique_ptr<__thread_struct> _TSPtr;
298    _TSPtr __tsp(new __thread_struct);
299    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
300    _VSTD::unique_ptr<_Gp> __p(
301            new _Gp(std::move(__tsp),
302                    __decay_copy(_VSTD::forward<_Fp>(__f)),
303                    __decay_copy(_VSTD::forward<_Args>(__args))...));
304    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
305    if (__ec == 0)
306        __p.release();
307    else
308        __throw_system_error(__ec, "thread constructor failed");
309}
310
311inline
312thread&
313thread::operator=(thread&& __t) _NOEXCEPT
314{
315    if (!__libcpp_thread_isnull(&__t_))
316        terminate();
317    __t_ = __t.__t_;
318    __t.__t_ = _LIBCPP_NULL_THREAD;
319    return *this;
320}
321
322#else  // _LIBCPP_CXX03_LANG
323
324template <class _Fp>
325struct __thread_invoke_pair {
326    // This type is used to pass memory for thread local storage and a functor
327    // to a newly created thread because std::pair doesn't work with
328    // std::unique_ptr in C++03.
329    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
330    unique_ptr<__thread_struct> __tsp_;
331    _Fp __fn_;
332};
333
334template <class _Fp>
335void* __thread_proxy_cxx03(void* __vp)
336{
337    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
338    __thread_local_data().set_pointer(__p->__tsp_.release());
339    (__p->__fn_)();
340    return nullptr;
341}
342
343template <class _Fp>
344thread::thread(_Fp __f)
345{
346
347    typedef __thread_invoke_pair<_Fp> _InvokePair;
348    typedef std::unique_ptr<_InvokePair> _PairPtr;
349    _PairPtr __pp(new _InvokePair(__f));
350    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
351    if (__ec == 0)
352        __pp.release();
353    else
354        __throw_system_error(__ec, "thread constructor failed");
355}
356
357#endif  // _LIBCPP_CXX03_LANG
358
359inline _LIBCPP_INLINE_VISIBILITY
360void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
361
362namespace this_thread
363{
364
365_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& __ns);
366
367template <class _Rep, class _Period>
368void
369sleep_for(const chrono::duration<_Rep, _Period>& __d)
370{
371    using namespace chrono;
372    if (__d > duration<_Rep, _Period>::zero())
373    {
374        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
375        nanoseconds __ns;
376        if (__d < _Max)
377        {
378            __ns = duration_cast<nanoseconds>(__d);
379            if (__ns < __d)
380                ++__ns;
381        }
382        else
383            __ns = nanoseconds::max();
384        sleep_for(__ns);
385    }
386}
387
388template <class _Clock, class _Duration>
389void
390sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
391{
392    using namespace chrono;
393    mutex __mut;
394    condition_variable __cv;
395    unique_lock<mutex> __lk(__mut);
396    while (_Clock::now() < __t)
397        __cv.wait_until(__lk, __t);
398}
399
400template <class _Duration>
401inline _LIBCPP_INLINE_VISIBILITY
402void
403sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
404{
405    using namespace chrono;
406    sleep_for(__t - steady_clock::now());
407}
408
409inline _LIBCPP_INLINE_VISIBILITY
410void yield() _NOEXCEPT {__libcpp_thread_yield();}
411
412}  // this_thread
413
414_LIBCPP_END_NAMESPACE_STD
415
416#endif // !_LIBCPP_HAS_NO_THREADS
417
418_LIBCPP_POP_MACROS
419
420#endif  // _LIBCPP_THREAD
421