xref: /freebsd/contrib/llvm-project/libcxx/include/mutex (revision 3e8eb5c7f4909209c042403ddee340b2ee7003a5) 
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_MUTEX
11#define _LIBCPP_MUTEX
12
13/*
14    mutex synopsis
15
16namespace std
17{
18
19class mutex
20{
21public:
22     constexpr mutex() noexcept;
23     ~mutex();
24
25    mutex(const mutex&) = delete;
26    mutex& operator=(const mutex&) = delete;
27
28    void lock();
29    bool try_lock();
30    void unlock();
31
32    typedef pthread_mutex_t* native_handle_type;
33    native_handle_type native_handle();
34};
35
36class recursive_mutex
37{
38public:
39     recursive_mutex();
40     ~recursive_mutex();
41
42    recursive_mutex(const recursive_mutex&) = delete;
43    recursive_mutex& operator=(const recursive_mutex&) = delete;
44
45    void lock();
46    bool try_lock() noexcept;
47    void unlock();
48
49    typedef pthread_mutex_t* native_handle_type;
50    native_handle_type native_handle();
51};
52
53class timed_mutex
54{
55public:
56     timed_mutex();
57     ~timed_mutex();
58
59    timed_mutex(const timed_mutex&) = delete;
60    timed_mutex& operator=(const timed_mutex&) = delete;
61
62    void lock();
63    bool try_lock();
64    template <class Rep, class Period>
65        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
66    template <class Clock, class Duration>
67        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
68    void unlock();
69};
70
71class recursive_timed_mutex
72{
73public:
74     recursive_timed_mutex();
75     ~recursive_timed_mutex();
76
77    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
78    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
79
80    void lock();
81    bool try_lock() noexcept;
82    template <class Rep, class Period>
83        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
84    template <class Clock, class Duration>
85        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
86    void unlock();
87};
88
89struct defer_lock_t { explicit defer_lock_t() = default; };
90struct try_to_lock_t { explicit try_to_lock_t() = default; };
91struct adopt_lock_t { explicit adopt_lock_t() = default; };
92
93inline constexpr defer_lock_t  defer_lock{};
94inline constexpr try_to_lock_t try_to_lock{};
95inline constexpr adopt_lock_t  adopt_lock{};
96
97template <class Mutex>
98class lock_guard
99{
100public:
101    typedef Mutex mutex_type;
102
103    explicit lock_guard(mutex_type& m);
104    lock_guard(mutex_type& m, adopt_lock_t);
105    ~lock_guard();
106
107    lock_guard(lock_guard const&) = delete;
108    lock_guard& operator=(lock_guard const&) = delete;
109};
110
111template <class... MutexTypes>
112class scoped_lock // C++17
113{
114public:
115    using mutex_type = Mutex;  // Only if sizeof...(MutexTypes) == 1
116
117    explicit scoped_lock(MutexTypes&... m);
118    scoped_lock(adopt_lock_t, MutexTypes&... m);
119    ~scoped_lock();
120    scoped_lock(scoped_lock const&) = delete;
121    scoped_lock& operator=(scoped_lock const&) = delete;
122private:
123    tuple<MutexTypes&...> pm; // exposition only
124};
125
126template <class Mutex>
127class unique_lock
128{
129public:
130    typedef Mutex mutex_type;
131    unique_lock() noexcept;
132    explicit unique_lock(mutex_type& m);
133    unique_lock(mutex_type& m, defer_lock_t) noexcept;
134    unique_lock(mutex_type& m, try_to_lock_t);
135    unique_lock(mutex_type& m, adopt_lock_t);
136    template <class Clock, class Duration>
137        unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
138    template <class Rep, class Period>
139        unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
140    ~unique_lock();
141
142    unique_lock(unique_lock const&) = delete;
143    unique_lock& operator=(unique_lock const&) = delete;
144
145    unique_lock(unique_lock&& u) noexcept;
146    unique_lock& operator=(unique_lock&& u) noexcept;
147
148    void lock();
149    bool try_lock();
150
151    template <class Rep, class Period>
152        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
153    template <class Clock, class Duration>
154        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
155
156    void unlock();
157
158    void swap(unique_lock& u) noexcept;
159    mutex_type* release() noexcept;
160
161    bool owns_lock() const noexcept;
162    explicit operator bool () const noexcept;
163    mutex_type* mutex() const noexcept;
164};
165
166template <class Mutex>
167  void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
168
169template <class L1, class L2, class... L3>
170  int try_lock(L1&, L2&, L3&...);
171template <class L1, class L2, class... L3>
172  void lock(L1&, L2&, L3&...);
173
174struct once_flag
175{
176    constexpr once_flag() noexcept;
177
178    once_flag(const once_flag&) = delete;
179    once_flag& operator=(const once_flag&) = delete;
180};
181
182template<class Callable, class ...Args>
183  void call_once(once_flag& flag, Callable&& func, Args&&... args);
184
185}  // std
186
187*/
188
189#include <__config>
190#include <__mutex_base>
191#include <__threading_support>
192#include <__utility/forward.h>
193#include <cstdint>
194#include <functional>
195#include <memory>
196#ifndef _LIBCPP_CXX03_LANG
197# include <tuple>
198#endif
199#include <version>
200
201#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
202#pragma GCC system_header
203#endif
204
205_LIBCPP_PUSH_MACROS
206#include <__undef_macros>
207
208
209_LIBCPP_BEGIN_NAMESPACE_STD
210
211#ifndef _LIBCPP_HAS_NO_THREADS
212
213class _LIBCPP_TYPE_VIS recursive_mutex
214{
215    __libcpp_recursive_mutex_t __m_;
216
217public:
218    recursive_mutex();
219    ~recursive_mutex();
220
221    recursive_mutex(const recursive_mutex&) = delete;
222    recursive_mutex& operator=(const recursive_mutex&) = delete;
223
224    void lock();
225    bool try_lock() _NOEXCEPT;
226    void unlock()  _NOEXCEPT;
227
228    typedef __libcpp_recursive_mutex_t* native_handle_type;
229
230    _LIBCPP_INLINE_VISIBILITY
231    native_handle_type native_handle() {return &__m_;}
232};
233
234class _LIBCPP_TYPE_VIS timed_mutex
235{
236    mutex              __m_;
237    condition_variable __cv_;
238    bool               __locked_;
239public:
240     timed_mutex();
241     ~timed_mutex();
242
243    timed_mutex(const timed_mutex&) = delete;
244    timed_mutex& operator=(const timed_mutex&) = delete;
245
246public:
247    void lock();
248    bool try_lock() _NOEXCEPT;
249    template <class _Rep, class _Period>
250        _LIBCPP_INLINE_VISIBILITY
251        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
252            {return try_lock_until(chrono::steady_clock::now() + __d);}
253    template <class _Clock, class _Duration>
254        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
255        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
256    void unlock() _NOEXCEPT;
257};
258
259template <class _Clock, class _Duration>
260bool
261timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
262{
263    using namespace chrono;
264    unique_lock<mutex> __lk(__m_);
265    bool no_timeout = _Clock::now() < __t;
266    while (no_timeout && __locked_)
267        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
268    if (!__locked_)
269    {
270        __locked_ = true;
271        return true;
272    }
273    return false;
274}
275
276class _LIBCPP_TYPE_VIS recursive_timed_mutex
277{
278    mutex              __m_;
279    condition_variable __cv_;
280    size_t             __count_;
281    __thread_id        __id_;
282public:
283    recursive_timed_mutex();
284    ~recursive_timed_mutex();
285
286    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
287    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
288
289    void lock();
290    bool try_lock() _NOEXCEPT;
291    template <class _Rep, class _Period>
292        _LIBCPP_INLINE_VISIBILITY
293        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
294            {return try_lock_until(chrono::steady_clock::now() + __d);}
295    template <class _Clock, class _Duration>
296        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
297        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
298    void unlock() _NOEXCEPT;
299};
300
301template <class _Clock, class _Duration>
302bool
303recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
304{
305    using namespace chrono;
306    __thread_id __id = this_thread::get_id();
307    unique_lock<mutex> lk(__m_);
308    if (__id == __id_)
309    {
310        if (__count_ == numeric_limits<size_t>::max())
311            return false;
312        ++__count_;
313        return true;
314    }
315    bool no_timeout = _Clock::now() < __t;
316    while (no_timeout && __count_ != 0)
317        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
318    if (__count_ == 0)
319    {
320        __count_ = 1;
321        __id_ = __id;
322        return true;
323    }
324    return false;
325}
326
327template <class _L0, class _L1>
328int
329try_lock(_L0& __l0, _L1& __l1)
330{
331    unique_lock<_L0> __u0(__l0, try_to_lock);
332    if (__u0.owns_lock())
333    {
334        if (__l1.try_lock())
335        {
336            __u0.release();
337            return -1;
338        }
339        else
340            return 1;
341    }
342    return 0;
343}
344
345#ifndef _LIBCPP_CXX03_LANG
346
347template <class _L0, class _L1, class _L2, class... _L3>
348int
349try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
350{
351    int __r = 0;
352    unique_lock<_L0> __u0(__l0, try_to_lock);
353    if (__u0.owns_lock())
354    {
355        __r = try_lock(__l1, __l2, __l3...);
356        if (__r == -1)
357            __u0.release();
358        else
359            ++__r;
360    }
361    return __r;
362}
363
364#endif // _LIBCPP_CXX03_LANG
365
366template <class _L0, class _L1>
367void
368lock(_L0& __l0, _L1& __l1)
369{
370    while (true)
371    {
372        {
373            unique_lock<_L0> __u0(__l0);
374            if (__l1.try_lock())
375            {
376                __u0.release();
377                break;
378            }
379        }
380        __libcpp_thread_yield();
381        {
382            unique_lock<_L1> __u1(__l1);
383            if (__l0.try_lock())
384            {
385                __u1.release();
386                break;
387            }
388        }
389        __libcpp_thread_yield();
390    }
391}
392
393#ifndef _LIBCPP_CXX03_LANG
394
395template <class _L0, class _L1, class _L2, class ..._L3>
396void
397__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
398{
399    while (true)
400    {
401        switch (__i)
402        {
403        case 0:
404            {
405                unique_lock<_L0> __u0(__l0);
406                __i = try_lock(__l1, __l2, __l3...);
407                if (__i == -1)
408                {
409                    __u0.release();
410                    return;
411                }
412            }
413            ++__i;
414            __libcpp_thread_yield();
415            break;
416        case 1:
417            {
418                unique_lock<_L1> __u1(__l1);
419                __i = try_lock(__l2, __l3..., __l0);
420                if (__i == -1)
421                {
422                    __u1.release();
423                    return;
424                }
425            }
426            if (__i == sizeof...(_L3) + 1)
427                __i = 0;
428            else
429                __i += 2;
430            __libcpp_thread_yield();
431            break;
432        default:
433            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
434            return;
435        }
436    }
437}
438
439template <class _L0, class _L1, class _L2, class ..._L3>
440inline _LIBCPP_INLINE_VISIBILITY
441void
442lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
443{
444    __lock_first(0, __l0, __l1, __l2, __l3...);
445}
446
447template <class _L0>
448inline _LIBCPP_INLINE_VISIBILITY
449void __unlock(_L0& __l0) {
450    __l0.unlock();
451}
452
453template <class _L0, class _L1>
454inline _LIBCPP_INLINE_VISIBILITY
455void __unlock(_L0& __l0, _L1& __l1) {
456    __l0.unlock();
457    __l1.unlock();
458}
459
460template <class _L0, class _L1, class _L2, class ..._L3>
461inline _LIBCPP_INLINE_VISIBILITY
462void __unlock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3) {
463    __l0.unlock();
464    __l1.unlock();
465    _VSTD::__unlock(__l2, __l3...);
466}
467
468#endif // _LIBCPP_CXX03_LANG
469
470#if _LIBCPP_STD_VER > 14
471template <class ..._Mutexes>
472class _LIBCPP_TEMPLATE_VIS scoped_lock;
473
474template <>
475class _LIBCPP_TEMPLATE_VIS scoped_lock<> {
476public:
477    explicit scoped_lock() {}
478    ~scoped_lock() = default;
479
480    _LIBCPP_INLINE_VISIBILITY
481    explicit scoped_lock(adopt_lock_t) {}
482
483    scoped_lock(scoped_lock const&) = delete;
484    scoped_lock& operator=(scoped_lock const&) = delete;
485};
486
487template <class _Mutex>
488class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable) scoped_lock<_Mutex> {
489public:
490    typedef _Mutex  mutex_type;
491private:
492    mutex_type& __m_;
493public:
494    explicit scoped_lock(mutex_type & __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
495        : __m_(__m) {__m_.lock();}
496
497    ~scoped_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
498
499    _LIBCPP_INLINE_VISIBILITY
500    explicit scoped_lock(adopt_lock_t, mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
501        : __m_(__m) {}
502
503    scoped_lock(scoped_lock const&) = delete;
504    scoped_lock& operator=(scoped_lock const&) = delete;
505};
506
507template <class ..._MArgs>
508class _LIBCPP_TEMPLATE_VIS scoped_lock
509{
510    static_assert(sizeof...(_MArgs) > 1, "At least 2 lock types required");
511    typedef tuple<_MArgs&...> _MutexTuple;
512
513public:
514    _LIBCPP_INLINE_VISIBILITY
515    explicit scoped_lock(_MArgs&... __margs)
516      : __t_(__margs...)
517    {
518        _VSTD::lock(__margs...);
519    }
520
521    _LIBCPP_INLINE_VISIBILITY
522    scoped_lock(adopt_lock_t, _MArgs&... __margs)
523        : __t_(__margs...)
524    {
525    }
526
527    _LIBCPP_INLINE_VISIBILITY
528    ~scoped_lock() {
529        typedef typename __make_tuple_indices<sizeof...(_MArgs)>::type _Indices;
530        __unlock_unpack(_Indices{}, __t_);
531    }
532
533    scoped_lock(scoped_lock const&) = delete;
534    scoped_lock& operator=(scoped_lock const&) = delete;
535
536private:
537    template <size_t ..._Indx>
538    _LIBCPP_INLINE_VISIBILITY
539    static void __unlock_unpack(__tuple_indices<_Indx...>, _MutexTuple& __mt) {
540        _VSTD::__unlock(_VSTD::get<_Indx>(__mt)...);
541    }
542
543    _MutexTuple __t_;
544};
545
546#endif // _LIBCPP_STD_VER > 14
547#endif // !_LIBCPP_HAS_NO_THREADS
548
549struct _LIBCPP_TEMPLATE_VIS once_flag;
550
551#ifndef _LIBCPP_CXX03_LANG
552
553template<class _Callable, class... _Args>
554_LIBCPP_INLINE_VISIBILITY
555void call_once(once_flag&, _Callable&&, _Args&&...);
556
557#else  // _LIBCPP_CXX03_LANG
558
559template<class _Callable>
560_LIBCPP_INLINE_VISIBILITY
561void call_once(once_flag&, _Callable&);
562
563template<class _Callable>
564_LIBCPP_INLINE_VISIBILITY
565void call_once(once_flag&, const _Callable&);
566
567#endif // _LIBCPP_CXX03_LANG
568
569struct _LIBCPP_TEMPLATE_VIS once_flag
570{
571    _LIBCPP_INLINE_VISIBILITY
572    _LIBCPP_CONSTEXPR
573        once_flag() _NOEXCEPT : __state_(0) {}
574    once_flag(const once_flag&) = delete;
575    once_flag& operator=(const once_flag&) = delete;
576
577#if defined(_LIBCPP_ABI_MICROSOFT)
578   typedef uintptr_t _State_type;
579#else
580   typedef unsigned long _State_type;
581#endif
582
583private:
584    _State_type __state_;
585
586#ifndef _LIBCPP_CXX03_LANG
587    template<class _Callable, class... _Args>
588    friend
589    void call_once(once_flag&, _Callable&&, _Args&&...);
590#else  // _LIBCPP_CXX03_LANG
591    template<class _Callable>
592    friend
593    void call_once(once_flag&, _Callable&);
594
595    template<class _Callable>
596    friend
597    void call_once(once_flag&, const _Callable&);
598#endif // _LIBCPP_CXX03_LANG
599};
600
601#ifndef _LIBCPP_CXX03_LANG
602
603template <class _Fp>
604class __call_once_param
605{
606    _Fp& __f_;
607public:
608    _LIBCPP_INLINE_VISIBILITY
609    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
610
611    _LIBCPP_INLINE_VISIBILITY
612    void operator()()
613    {
614        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
615        __execute(_Index());
616    }
617
618private:
619    template <size_t ..._Indices>
620    _LIBCPP_INLINE_VISIBILITY
621    void __execute(__tuple_indices<_Indices...>)
622    {
623        _VSTD::__invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
624    }
625};
626
627#else
628
629template <class _Fp>
630class __call_once_param
631{
632    _Fp& __f_;
633public:
634    _LIBCPP_INLINE_VISIBILITY
635    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
636
637    _LIBCPP_INLINE_VISIBILITY
638    void operator()()
639    {
640        __f_();
641    }
642};
643
644#endif
645
646template <class _Fp>
647void _LIBCPP_INLINE_VISIBILITY
648__call_once_proxy(void* __vp)
649{
650    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
651    (*__p)();
652}
653
654_LIBCPP_FUNC_VIS void __call_once(volatile once_flag::_State_type&, void*,
655                                  void (*)(void*));
656
657#ifndef _LIBCPP_CXX03_LANG
658
659template<class _Callable, class... _Args>
660inline _LIBCPP_INLINE_VISIBILITY
661void
662call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
663{
664    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
665    {
666        typedef tuple<_Callable&&, _Args&&...> _Gp;
667        _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
668        __call_once_param<_Gp> __p(__f);
669        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
670    }
671}
672
673#else  // _LIBCPP_CXX03_LANG
674
675template<class _Callable>
676inline _LIBCPP_INLINE_VISIBILITY
677void
678call_once(once_flag& __flag, _Callable& __func)
679{
680    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
681    {
682        __call_once_param<_Callable> __p(__func);
683        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
684    }
685}
686
687template<class _Callable>
688inline _LIBCPP_INLINE_VISIBILITY
689void
690call_once(once_flag& __flag, const _Callable& __func)
691{
692    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
693    {
694        __call_once_param<const _Callable> __p(__func);
695        __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
696    }
697}
698
699#endif // _LIBCPP_CXX03_LANG
700
701_LIBCPP_END_NAMESPACE_STD
702
703_LIBCPP_POP_MACROS
704
705#endif // _LIBCPP_MUTEX
706