xref: /llvm-project-15.0.7/libcxx/include/thread (revision 498ee00a) 
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#include <__debug>
103
104#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
105#pragma GCC system_header
106#endif
107
108#define __STDCPP_THREADS__ __cplusplus
109
110#ifdef _LIBCPP_HAS_NO_THREADS
111#error <thread> is not supported on this single threaded system
112#else // !_LIBCPP_HAS_NO_THREADS
113
114_LIBCPP_BEGIN_NAMESPACE_STD
115
116template <class _Tp> class __thread_specific_ptr;
117class _LIBCPP_TYPE_VIS __thread_struct;
118class _LIBCPP_HIDDEN __thread_struct_imp;
119class __assoc_sub_state;
120
121_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
122
123class _LIBCPP_TYPE_VIS __thread_struct
124{
125    __thread_struct_imp* __p_;
126
127    __thread_struct(const __thread_struct&);
128    __thread_struct& operator=(const __thread_struct&);
129public:
130    __thread_struct();
131    ~__thread_struct();
132
133    void notify_all_at_thread_exit(condition_variable*, mutex*);
134    void __make_ready_at_thread_exit(__assoc_sub_state*);
135};
136
137template <class _Tp>
138class __thread_specific_ptr
139{
140    __libcpp_tls_key __key_;
141
142     // Only __thread_local_data() may construct a __thread_specific_ptr
143     // and only with _Tp == __thread_struct.
144    static_assert((is_same<_Tp, __thread_struct>::value), "");
145    __thread_specific_ptr();
146    friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
147
148    __thread_specific_ptr(const __thread_specific_ptr&);
149    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
150
151    static void __at_thread_exit(void*);
152public:
153    typedef _Tp* pointer;
154
155    ~__thread_specific_ptr();
156
157    _LIBCPP_INLINE_VISIBILITY
158    pointer get() const {return static_cast<_Tp*>(__libcpp_tls_get(__key_));}
159    _LIBCPP_INLINE_VISIBILITY
160    pointer operator*() const {return *get();}
161    _LIBCPP_INLINE_VISIBILITY
162    pointer operator->() const {return get();}
163    void set_pointer(pointer __p);
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_tls_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>
194void
195__thread_specific_ptr<_Tp>::set_pointer(pointer __p)
196{
197    _LIBCPP_ASSERT(get() == nullptr,
198                   "Attempting to overwrite thread local data");
199    __libcpp_tls_set(__key_, __p);
200}
201
202class _LIBCPP_TYPE_VIS thread;
203class _LIBCPP_TYPE_VIS __thread_id;
204
205namespace this_thread
206{
207
208_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
209
210}  // this_thread
211
212template<> struct hash<__thread_id>;
213
214class _LIBCPP_TYPE_VIS_ONLY __thread_id
215{
216    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
217    // NULL is the no-thread value on Darwin.  Someone needs to check
218    // on other platforms.  We assume 0 works everywhere for now.
219    __libcpp_thread_id __id_;
220
221public:
222    _LIBCPP_INLINE_VISIBILITY
223    __thread_id() _NOEXCEPT : __id_(0) {}
224
225    friend _LIBCPP_INLINE_VISIBILITY
226        bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
227        {return __libcpp_thread_id_equal(__x.__id_, __y.__id_);}
228    friend _LIBCPP_INLINE_VISIBILITY
229        bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
230        {return !(__x == __y);}
231    friend _LIBCPP_INLINE_VISIBILITY
232        bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
233        {return  __libcpp_thread_id_less(__x.__id_, __y.__id_);}
234    friend _LIBCPP_INLINE_VISIBILITY
235        bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
236        {return !(__y < __x);}
237    friend _LIBCPP_INLINE_VISIBILITY
238        bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
239        {return   __y < __x ;}
240    friend _LIBCPP_INLINE_VISIBILITY
241        bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
242        {return !(__x < __y);}
243
244    template<class _CharT, class _Traits>
245    friend
246    _LIBCPP_INLINE_VISIBILITY
247    basic_ostream<_CharT, _Traits>&
248    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
249        {return __os << __id.__id_;}
250
251private:
252    _LIBCPP_INLINE_VISIBILITY
253    __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
254
255    friend __thread_id this_thread::get_id() _NOEXCEPT;
256    friend class _LIBCPP_TYPE_VIS thread;
257    friend struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>;
258};
259
260template<>
261struct _LIBCPP_TYPE_VIS_ONLY hash<__thread_id>
262    : public unary_function<__thread_id, size_t>
263{
264    _LIBCPP_INLINE_VISIBILITY
265    size_t operator()(__thread_id __v) const
266    {
267        return hash<__libcpp_thread_id>()(__v.__id_);
268    }
269};
270
271namespace this_thread
272{
273
274inline _LIBCPP_INLINE_VISIBILITY
275__thread_id
276get_id() _NOEXCEPT
277{
278    return __libcpp_thread_get_current_id();
279}
280
281}  // this_thread
282
283class _LIBCPP_TYPE_VIS thread
284{
285    __libcpp_thread_t __t_;
286
287    thread(const thread&);
288    thread& operator=(const thread&);
289public:
290    typedef __thread_id id;
291    typedef __libcpp_thread_t native_handle_type;
292
293    _LIBCPP_INLINE_VISIBILITY
294    thread() _NOEXCEPT : __t_(0) {}
295#ifndef _LIBCPP_HAS_NO_VARIADICS
296    template <class _Fp, class ..._Args,
297              class = typename enable_if
298              <
299                   !is_same<typename decay<_Fp>::type, thread>::value
300              >::type
301             >
302        explicit thread(_Fp&& __f, _Args&&... __args);
303#else  // _LIBCPP_HAS_NO_VARIADICS
304    template <class _Fp> explicit thread(_Fp __f);
305#endif
306    ~thread();
307
308#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
309    _LIBCPP_INLINE_VISIBILITY
310    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = 0;}
311    _LIBCPP_INLINE_VISIBILITY
312    thread& operator=(thread&& __t) _NOEXCEPT;
313#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
314
315    _LIBCPP_INLINE_VISIBILITY
316    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
317
318    _LIBCPP_INLINE_VISIBILITY
319    bool joinable() const _NOEXCEPT {return __t_ != 0;}
320    void join();
321    void detach();
322    _LIBCPP_INLINE_VISIBILITY
323    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
324    _LIBCPP_INLINE_VISIBILITY
325    native_handle_type native_handle() _NOEXCEPT {return __t_;}
326
327    static unsigned hardware_concurrency() _NOEXCEPT;
328};
329
330#ifndef _LIBCPP_HAS_NO_VARIADICS
331
332template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
333inline _LIBCPP_INLINE_VISIBILITY
334void
335__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
336{
337    __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
338}
339
340template <class _Fp>
341void* __thread_proxy(void* __vp)
342{
343    // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
344    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
345    __thread_local_data().set_pointer(_VSTD::get<0>(*__p).release());
346    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
347    __thread_execute(*__p, _Index());
348    return nullptr;
349}
350
351template <class _Fp, class ..._Args,
352          class
353         >
354thread::thread(_Fp&& __f, _Args&&... __args)
355{
356    typedef unique_ptr<__thread_struct> _TSPtr;
357    _TSPtr __tsp(new __thread_struct);
358    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
359    _VSTD::unique_ptr<_Gp> __p(
360            new _Gp(std::move(__tsp),
361                    __decay_copy(_VSTD::forward<_Fp>(__f)),
362                    __decay_copy(_VSTD::forward<_Args>(__args))...));
363    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
364    if (__ec == 0)
365        __p.release();
366    else
367        __throw_system_error(__ec, "thread constructor failed");
368}
369
370#else  // _LIBCPP_HAS_NO_VARIADICS
371
372template <class _Fp>
373struct __thread_invoke_pair {
374    // This type is used to pass memory for thread local storage and a functor
375    // to a newly created thread because std::pair doesn't work with
376    // std::unique_ptr in C++03.
377    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
378    unique_ptr<__thread_struct> __tsp_;
379    _Fp __fn_;
380};
381
382template <class _Fp>
383void* __thread_proxy_cxx03(void* __vp)
384{
385    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
386    __thread_local_data().set_pointer(__p->__tsp_.release());
387    (__p->__fn_)();
388    return nullptr;
389}
390
391template <class _Fp>
392thread::thread(_Fp __f)
393{
394
395    typedef __thread_invoke_pair<_Fp> _InvokePair;
396    typedef std::unique_ptr<_InvokePair> _PairPtr;
397    _PairPtr __pp(new _InvokePair(__f));
398    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
399    if (__ec == 0)
400        __pp.release();
401    else
402        __throw_system_error(__ec, "thread constructor failed");
403}
404
405#endif  // _LIBCPP_HAS_NO_VARIADICS
406
407#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
408
409inline
410thread&
411thread::operator=(thread&& __t) _NOEXCEPT
412{
413    if (__t_ != 0)
414        terminate();
415    __t_ = __t.__t_;
416    __t.__t_ = 0;
417    return *this;
418}
419
420#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
421
422inline _LIBCPP_INLINE_VISIBILITY
423void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
424
425namespace this_thread
426{
427
428_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& ns);
429
430template <class _Rep, class _Period>
431void
432sleep_for(const chrono::duration<_Rep, _Period>& __d)
433{
434    using namespace chrono;
435    if (__d > duration<_Rep, _Period>::zero())
436    {
437        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
438        nanoseconds __ns;
439        if (__d < _Max)
440        {
441            __ns = duration_cast<nanoseconds>(__d);
442            if (__ns < __d)
443                ++__ns;
444        }
445        else
446            __ns = nanoseconds::max();
447        sleep_for(__ns);
448    }
449}
450
451template <class _Clock, class _Duration>
452void
453sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
454{
455    using namespace chrono;
456    mutex __mut;
457    condition_variable __cv;
458    unique_lock<mutex> __lk(__mut);
459    while (_Clock::now() < __t)
460        __cv.wait_until(__lk, __t);
461}
462
463template <class _Duration>
464inline _LIBCPP_INLINE_VISIBILITY
465void
466sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
467{
468    using namespace chrono;
469    sleep_for(__t - steady_clock::now());
470}
471
472inline _LIBCPP_INLINE_VISIBILITY
473void yield() _NOEXCEPT {__libcpp_thread_yield();}
474
475}  // this_thread
476
477_LIBCPP_END_NAMESPACE_STD
478
479#endif // !_LIBCPP_HAS_NO_THREADS
480
481#endif  // _LIBCPP_THREAD
482