xref: /freebsd-12.1/contrib/libc++/include/thread (revision 2b375b4e) 
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_HAS_NO_VARIADICS
99#include <tuple>
100#endif
101#include <__threading_support>
102
103#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
104#pragma GCC system_header
105#endif
106
107#define __STDCPP_THREADS__ __cplusplus
108
109#ifdef _LIBCPP_HAS_NO_THREADS
110#error <thread> is not supported on this single threaded system
111#else // !_LIBCPP_HAS_NO_THREADS
112
113_LIBCPP_BEGIN_NAMESPACE_STD
114
115template <class _Tp> class __thread_specific_ptr;
116class _LIBCPP_TYPE_VIS __thread_struct;
117class _LIBCPP_HIDDEN __thread_struct_imp;
118class __assoc_sub_state;
119
120_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
121
122class _LIBCPP_TYPE_VIS __thread_struct
123{
124    __thread_struct_imp* __p_;
125
126    __thread_struct(const __thread_struct&);
127    __thread_struct& operator=(const __thread_struct&);
128public:
129    __thread_struct();
130    ~__thread_struct();
131
132    void notify_all_at_thread_exit(condition_variable*, mutex*);
133    void __make_ready_at_thread_exit(__assoc_sub_state*);
134};
135
136template <class _Tp>
137class __thread_specific_ptr
138{
139    __libcpp_tl_key __key_;
140
141     // Only __thread_local_data() may construct a __thread_specific_ptr
142     // and only with _Tp == __thread_struct.
143    static_assert((is_same<_Tp, __thread_struct>::value), "");
144    __thread_specific_ptr();
145    friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
146
147    __thread_specific_ptr(const __thread_specific_ptr&);
148    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
149
150    static void __at_thread_exit(void*);
151public:
152    typedef _Tp* pointer;
153
154    ~__thread_specific_ptr();
155
156    _LIBCPP_INLINE_VISIBILITY
157    pointer get() const {return static_cast<_Tp*>(__libcpp_tl_get(__key_));}
158    _LIBCPP_INLINE_VISIBILITY
159    pointer operator*() const {return *get();}
160    _LIBCPP_INLINE_VISIBILITY
161    pointer operator->() const {return get();}
162    pointer release();
163    void reset(pointer __p = nullptr);
164};
165
166template <class _Tp>
167void
168__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
169{
170    delete static_cast<pointer>(__p);
171}
172
173template <class _Tp>
174__thread_specific_ptr<_Tp>::__thread_specific_ptr()
175{
176    int __ec = __libcpp_tl_create(
177        &__key_,
178        &__thread_specific_ptr::__at_thread_exit);
179    if (__ec)
180        __throw_system_error(__ec,
181                           "__thread_specific_ptr construction failed");
182}
183
184template <class _Tp>
185__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
186{
187    // __thread_specific_ptr is only created with a static storage duration
188    // so this destructor is only invoked during program termination. Invoking
189    // pthread_key_delete(__key_) may prevent other threads from deleting their
190    // thread local data. For this reason we leak the key.
191}
192
193template <class _Tp>
194typename __thread_specific_ptr<_Tp>::pointer
195__thread_specific_ptr<_Tp>::release()
196{
197    pointer __p = get();
198    __libcpp_tl_set(__key_, nullptr);
199    return __p;
200}
201
202template <class _Tp>
203void
204__thread_specific_ptr<_Tp>::reset(pointer __p)
205{
206    pointer __p_old = get();
207    __libcpp_tl_set(__key_, __p);
208    delete __p_old;
209}
210
211class _LIBCPP_TYPE_VIS thread;
212class _LIBCPP_TYPE_VIS __thread_id;
213
214namespace this_thread
215{
216
217_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
218
219}  // this_thread
220
221template<> struct hash<__thread_id>;
222
223class _LIBCPP_TYPE_VIS_ONLY __thread_id
224{
225    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
226    // NULL is the no-thread value on Darwin.  Someone needs to check
227    // on other platforms.  We assume 0 works everywhere for now.
228    __libcpp_thread_id __id_;
229
230public:
231    _LIBCPP_INLINE_VISIBILITY
232    __thread_id() _NOEXCEPT : __id_(0) {}
233
234    friend _LIBCPP_INLINE_VISIBILITY
235        bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
236        {return __libcpp_thread_id_equal(__x.__id_, __y.__id_);}
237    friend _LIBCPP_INLINE_VISIBILITY
238        bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
239        {return !(__x == __y);}
240    friend _LIBCPP_INLINE_VISIBILITY
241        bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
242        {return  __libcpp_thread_id_less(__x.__id_, __y.__id_);}
243    friend _LIBCPP_INLINE_VISIBILITY
244        bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
245        {return !(__y < __x);}
246    friend _LIBCPP_INLINE_VISIBILITY
247        bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
248        {return   __y < __x ;}
249    friend _LIBCPP_INLINE_VISIBILITY
250        bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
251        {return !(__x < __y);}
252
253    template<class _CharT, class _Traits>
254    friend
255    _LIBCPP_INLINE_VISIBILITY
256    basic_ostream<_CharT, _Traits>&
257    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
258        {return __os << __id.__id_;}
259
260private:
261    _LIBCPP_INLINE_VISIBILITY
262    __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
263
264    friend __thread_id this_thread::get_id() _NOEXCEPT;
265    friend class _LIBCPP_TYPE_VIS thread;
266    friend struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;
267};
268
269template<>
270struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>
271    : public unary_function<__thread_id, size_t>
272{
273    _LIBCPP_INLINE_VISIBILITY
274    size_t operator()(__thread_id __v) const
275    {
276        return hash<__libcpp_thread_id>()(__v.__id_);
277    }
278};
279
280namespace this_thread
281{
282
283inline _LIBCPP_INLINE_VISIBILITY
284__thread_id
285get_id() _NOEXCEPT
286{
287    return __libcpp_thread_get_current_id();
288}
289
290}  // this_thread
291
292class _LIBCPP_TYPE_VIS thread
293{
294    __libcpp_thread_t __t_;
295
296    thread(const thread&);
297    thread& operator=(const thread&);
298public:
299    typedef __thread_id id;
300    typedef __libcpp_thread_t native_handle_type;
301
302    _LIBCPP_INLINE_VISIBILITY
303    thread() _NOEXCEPT : __t_(0) {}
304#ifndef _LIBCPP_HAS_NO_VARIADICS
305    template <class _Fp, class ..._Args,
306              class = typename enable_if
307              <
308                   !is_same<typename decay<_Fp>::type, thread>::value
309              >::type
310             >
311        explicit thread(_Fp&& __f, _Args&&... __args);
312#else  // _LIBCPP_HAS_NO_VARIADICS
313    template <class _Fp> explicit thread(_Fp __f);
314#endif
315    ~thread();
316
317#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
318    _LIBCPP_INLINE_VISIBILITY
319    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = 0;}
320    _LIBCPP_INLINE_VISIBILITY
321    thread& operator=(thread&& __t) _NOEXCEPT;
322#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
323
324    _LIBCPP_INLINE_VISIBILITY
325    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
326
327    _LIBCPP_INLINE_VISIBILITY
328    bool joinable() const _NOEXCEPT {return __t_ != 0;}
329    void join();
330    void detach();
331    _LIBCPP_INLINE_VISIBILITY
332    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
333    _LIBCPP_INLINE_VISIBILITY
334    native_handle_type native_handle() _NOEXCEPT {return __t_;}
335
336    static unsigned hardware_concurrency() _NOEXCEPT;
337};
338
339#ifndef _LIBCPP_HAS_NO_VARIADICS
340
341template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
342inline _LIBCPP_INLINE_VISIBILITY
343void
344__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
345{
346    __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
347}
348
349template <class _Fp>
350void* __thread_proxy(void* __vp)
351{
352    // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
353    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
354    __thread_local_data().reset(_VSTD::get<0>(*__p).release());
355    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
356    __thread_execute(*__p, _Index());
357    return nullptr;
358}
359
360template <class _Fp, class ..._Args,
361          class
362         >
363thread::thread(_Fp&& __f, _Args&&... __args)
364{
365    typedef unique_ptr<__thread_struct> _TSPtr;
366    _TSPtr __tsp(new __thread_struct);
367    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
368    _VSTD::unique_ptr<_Gp> __p(
369            new _Gp(std::move(__tsp),
370                    __decay_copy(_VSTD::forward<_Fp>(__f)),
371                    __decay_copy(_VSTD::forward<_Args>(__args))...));
372    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
373    if (__ec == 0)
374        __p.release();
375    else
376        __throw_system_error(__ec, "thread constructor failed");
377}
378
379#else  // _LIBCPP_HAS_NO_VARIADICS
380
381template <class _Fp>
382struct __thread_invoke_pair {
383    // This type is used to pass memory for thread local storage and a functor
384    // to a newly created thread because std::pair doesn't work with
385    // std::unique_ptr in C++03.
386    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
387    unique_ptr<__thread_struct> __tsp_;
388    _Fp __fn_;
389};
390
391template <class _Fp>
392void* __thread_proxy_cxx03(void* __vp)
393{
394    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
395    __thread_local_data().reset(__p->__tsp_.release());
396    (__p->__fn_)();
397    return nullptr;
398}
399
400template <class _Fp>
401thread::thread(_Fp __f)
402{
403
404    typedef __thread_invoke_pair<_Fp> _InvokePair;
405    typedef std::unique_ptr<_InvokePair> _PairPtr;
406    _PairPtr __pp(new _InvokePair(__f));
407    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
408    if (__ec == 0)
409        __pp.release();
410    else
411        __throw_system_error(__ec, "thread constructor failed");
412}
413
414#endif  // _LIBCPP_HAS_NO_VARIADICS
415
416#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
417
418inline
419thread&
420thread::operator=(thread&& __t) _NOEXCEPT
421{
422    if (__t_ != 0)
423        terminate();
424    __t_ = __t.__t_;
425    __t.__t_ = 0;
426    return *this;
427}
428
429#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
430
431inline _LIBCPP_INLINE_VISIBILITY
432void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
433
434namespace this_thread
435{
436
437_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& ns);
438
439template <class _Rep, class _Period>
440void
441sleep_for(const chrono::duration<_Rep, _Period>& __d)
442{
443    using namespace chrono;
444    if (__d > duration<_Rep, _Period>::zero())
445    {
446        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
447        nanoseconds __ns;
448        if (__d < _Max)
449        {
450            __ns = duration_cast<nanoseconds>(__d);
451            if (__ns < __d)
452                ++__ns;
453        }
454        else
455            __ns = nanoseconds::max();
456        sleep_for(__ns);
457    }
458}
459
460template <class _Clock, class _Duration>
461void
462sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
463{
464    using namespace chrono;
465    mutex __mut;
466    condition_variable __cv;
467    unique_lock<mutex> __lk(__mut);
468    while (_Clock::now() < __t)
469        __cv.wait_until(__lk, __t);
470}
471
472template <class _Duration>
473inline _LIBCPP_INLINE_VISIBILITY
474void
475sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
476{
477    using namespace chrono;
478    sleep_for(__t - steady_clock::now());
479}
480
481inline _LIBCPP_INLINE_VISIBILITY
482void yield() _NOEXCEPT {__libcpp_thread_yield();}
483
484}  // this_thread
485
486_LIBCPP_END_NAMESPACE_STD
487
488#endif // !_LIBCPP_HAS_NO_THREADS
489
490#endif  // _LIBCPP_THREAD
491