xref: /llvm-project-15.0.7/libcxx/include/thread (revision 37310769) 
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#ifndef _LIBCPP_NO_EXCEPTIONS
180    if (__ec)
181        throw system_error(error_code(__ec, system_category()),
182                           "__thread_specific_ptr construction failed");
183#endif
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>
196typename __thread_specific_ptr<_Tp>::pointer
197__thread_specific_ptr<_Tp>::release()
198{
199    pointer __p = get();
200    __libcpp_tl_set(__key_, nullptr);
201    return __p;
202}
203
204template <class _Tp>
205void
206__thread_specific_ptr<_Tp>::reset(pointer __p)
207{
208    pointer __p_old = get();
209    __libcpp_tl_set(__key_, __p);
210    delete __p_old;
211}
212
213class _LIBCPP_TYPE_VIS thread;
214class _LIBCPP_TYPE_VIS __thread_id;
215
216namespace this_thread
217{
218
219_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
220
221}  // this_thread
222
223template<> struct hash<__thread_id>;
224
225class _LIBCPP_TYPE_VIS_ONLY __thread_id
226{
227    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
228    // NULL is the no-thread value on Darwin.  Someone needs to check
229    // on other platforms.  We assume 0 works everywhere for now.
230    __libcpp_thread_id __id_;
231
232public:
233    _LIBCPP_INLINE_VISIBILITY
234    __thread_id() _NOEXCEPT : __id_(0) {}
235
236    friend _LIBCPP_INLINE_VISIBILITY
237        bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
238        {return __libcpp_thread_id_equal(__x.__id_, __y.__id_);}
239    friend _LIBCPP_INLINE_VISIBILITY
240        bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
241        {return !(__x == __y);}
242    friend _LIBCPP_INLINE_VISIBILITY
243        bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
244        {return  __libcpp_thread_id_less(__x.__id_, __y.__id_);}
245    friend _LIBCPP_INLINE_VISIBILITY
246        bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
247        {return !(__y < __x);}
248    friend _LIBCPP_INLINE_VISIBILITY
249        bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
250        {return   __y < __x ;}
251    friend _LIBCPP_INLINE_VISIBILITY
252        bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
253        {return !(__x < __y);}
254
255    template<class _CharT, class _Traits>
256    friend
257    _LIBCPP_INLINE_VISIBILITY
258    basic_ostream<_CharT, _Traits>&
259    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
260        {return __os << __id.__id_;}
261
262private:
263    _LIBCPP_INLINE_VISIBILITY
264    __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
265
266    friend __thread_id this_thread::get_id() _NOEXCEPT;
267    friend class _LIBCPP_TYPE_VIS thread;
268    friend struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;
269};
270
271template<>
272struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>
273    : public unary_function<__thread_id, size_t>
274{
275    _LIBCPP_INLINE_VISIBILITY
276    size_t operator()(__thread_id __v) const
277    {
278        return hash<__libcpp_thread_id>()(__v.__id_);
279    }
280};
281
282namespace this_thread
283{
284
285inline _LIBCPP_INLINE_VISIBILITY
286__thread_id
287get_id() _NOEXCEPT
288{
289    return __libcpp_thread_get_current_id();
290}
291
292}  // this_thread
293
294class _LIBCPP_TYPE_VIS thread
295{
296    __libcpp_thread_t __t_;
297
298    thread(const thread&);
299    thread& operator=(const thread&);
300public:
301    typedef __thread_id id;
302    typedef __libcpp_thread_t native_handle_type;
303
304    _LIBCPP_INLINE_VISIBILITY
305    thread() _NOEXCEPT : __t_(0) {}
306#ifndef _LIBCPP_HAS_NO_VARIADICS
307    template <class _Fp, class ..._Args,
308              class = typename enable_if
309              <
310                   !is_same<typename decay<_Fp>::type, thread>::value
311              >::type
312             >
313        explicit thread(_Fp&& __f, _Args&&... __args);
314#else  // _LIBCPP_HAS_NO_VARIADICS
315    template <class _Fp> explicit thread(_Fp __f);
316#endif
317    ~thread();
318
319#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
320    _LIBCPP_INLINE_VISIBILITY
321    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = 0;}
322    _LIBCPP_INLINE_VISIBILITY
323    thread& operator=(thread&& __t) _NOEXCEPT;
324#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
325
326    _LIBCPP_INLINE_VISIBILITY
327    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
328
329    _LIBCPP_INLINE_VISIBILITY
330    bool joinable() const _NOEXCEPT {return __t_ != 0;}
331    void join();
332    void detach();
333    _LIBCPP_INLINE_VISIBILITY
334    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
335    _LIBCPP_INLINE_VISIBILITY
336    native_handle_type native_handle() _NOEXCEPT {return __t_;}
337
338    static unsigned hardware_concurrency() _NOEXCEPT;
339};
340
341#ifndef _LIBCPP_HAS_NO_VARIADICS
342
343template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
344inline _LIBCPP_INLINE_VISIBILITY
345void
346__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
347{
348    __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
349}
350
351template <class _Fp>
352void* __thread_proxy(void* __vp)
353{
354    // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
355    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
356    __thread_local_data().reset(_VSTD::get<0>(*__p).release());
357    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
358    __thread_execute(*__p, _Index());
359    return nullptr;
360}
361
362template <class _Fp, class ..._Args,
363          class
364         >
365thread::thread(_Fp&& __f, _Args&&... __args)
366{
367    typedef unique_ptr<__thread_struct> _TSPtr;
368    _TSPtr __tsp(new __thread_struct);
369    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
370    _VSTD::unique_ptr<_Gp> __p(
371            new _Gp(std::move(__tsp),
372                    __decay_copy(_VSTD::forward<_Fp>(__f)),
373                    __decay_copy(_VSTD::forward<_Args>(__args))...));
374    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
375    if (__ec == 0)
376        __p.release();
377    else
378        __throw_system_error(__ec, "thread constructor failed");
379}
380
381#else  // _LIBCPP_HAS_NO_VARIADICS
382
383template <class _Fp>
384struct __thread_invoke_pair {
385    // This type is used to pass memory for thread local storage and a functor
386    // to a newly created thread because std::pair doesn't work with
387    // std::unique_ptr in C++03.
388    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
389    unique_ptr<__thread_struct> __tsp_;
390    _Fp __fn_;
391};
392
393template <class _Fp>
394void* __thread_proxy_cxx03(void* __vp)
395{
396    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
397    __thread_local_data().reset(__p->__tsp_.release());
398    (__p->__fn_)();
399    return nullptr;
400}
401
402template <class _Fp>
403thread::thread(_Fp __f)
404{
405
406    typedef __thread_invoke_pair<_Fp> _InvokePair;
407    typedef std::unique_ptr<_InvokePair> _PairPtr;
408    _PairPtr __pp(new _InvokePair(__f));
409    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
410    if (__ec == 0)
411        __pp.release();
412    else
413        __throw_system_error(__ec, "thread constructor failed");
414}
415
416#endif  // _LIBCPP_HAS_NO_VARIADICS
417
418#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
419
420inline
421thread&
422thread::operator=(thread&& __t) _NOEXCEPT
423{
424    if (__t_ != 0)
425        terminate();
426    __t_ = __t.__t_;
427    __t.__t_ = 0;
428    return *this;
429}
430
431#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
432
433inline _LIBCPP_INLINE_VISIBILITY
434void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
435
436namespace this_thread
437{
438
439_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& ns);
440
441template <class _Rep, class _Period>
442void
443sleep_for(const chrono::duration<_Rep, _Period>& __d)
444{
445    using namespace chrono;
446    if (__d > duration<_Rep, _Period>::zero())
447    {
448        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
449        nanoseconds __ns;
450        if (__d < _Max)
451        {
452            __ns = duration_cast<nanoseconds>(__d);
453            if (__ns < __d)
454                ++__ns;
455        }
456        else
457            __ns = nanoseconds::max();
458        sleep_for(__ns);
459    }
460}
461
462template <class _Clock, class _Duration>
463void
464sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
465{
466    using namespace chrono;
467    mutex __mut;
468    condition_variable __cv;
469    unique_lock<mutex> __lk(__mut);
470    while (_Clock::now() < __t)
471        __cv.wait_until(__lk, __t);
472}
473
474template <class _Duration>
475inline _LIBCPP_INLINE_VISIBILITY
476void
477sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
478{
479    using namespace chrono;
480    sleep_for(__t - steady_clock::now());
481}
482
483inline _LIBCPP_INLINE_VISIBILITY
484void yield() _NOEXCEPT {__libcpp_thread_yield();}
485
486}  // this_thread
487
488_LIBCPP_END_NAMESPACE_STD
489
490#endif // !_LIBCPP_HAS_NO_THREADS
491
492#endif  // _LIBCPP_THREAD
493