xref: /freebsd-12.1/contrib/libc++/include/mutex (revision 9fe44df2) 
1// -*- C++ -*-
2//===--------------------------- mutex ------------------------------------===//
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_MUTEX
12#define _LIBCPP_MUTEX
13
14/*
15    mutex synopsis
16
17namespace std
18{
19
20class mutex
21{
22public:
23     constexpr mutex() noexcept;
24     ~mutex();
25
26    mutex(const mutex&) = delete;
27    mutex& operator=(const mutex&) = delete;
28
29    void lock();
30    bool try_lock();
31    void unlock();
32
33    typedef pthread_mutex_t* native_handle_type;
34    native_handle_type native_handle();
35};
36
37class recursive_mutex
38{
39public:
40     recursive_mutex();
41     ~recursive_mutex();
42
43    recursive_mutex(const recursive_mutex&) = delete;
44    recursive_mutex& operator=(const recursive_mutex&) = delete;
45
46    void lock();
47    bool try_lock() noexcept;
48    void unlock();
49
50    typedef pthread_mutex_t* native_handle_type;
51    native_handle_type native_handle();
52};
53
54class timed_mutex
55{
56public:
57     timed_mutex();
58     ~timed_mutex();
59
60    timed_mutex(const timed_mutex&) = delete;
61    timed_mutex& operator=(const timed_mutex&) = delete;
62
63    void lock();
64    bool try_lock();
65    template <class Rep, class Period>
66        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
67    template <class Clock, class Duration>
68        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
69    void unlock();
70};
71
72class recursive_timed_mutex
73{
74public:
75     recursive_timed_mutex();
76     ~recursive_timed_mutex();
77
78    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
79    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
80
81    void lock();
82    bool try_lock() noexcept;
83    template <class Rep, class Period>
84        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
85    template <class Clock, class Duration>
86        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
87    void unlock();
88};
89
90struct defer_lock_t {};
91struct try_to_lock_t {};
92struct adopt_lock_t {};
93
94constexpr defer_lock_t  defer_lock{};
95constexpr try_to_lock_t try_to_lock{};
96constexpr adopt_lock_t  adopt_lock{};
97
98template <class Mutex>
99class lock_guard
100{
101public:
102    typedef Mutex mutex_type;
103
104    explicit lock_guard(mutex_type& m);
105    lock_guard(mutex_type& m, adopt_lock_t);
106    ~lock_guard();
107
108    lock_guard(lock_guard const&) = delete;
109    lock_guard& operator=(lock_guard const&) = delete;
110};
111
112template <class... MutexTypes> // Variadic lock_guard only provided in ABI V2.
113class lock_guard
114{
115public:
116    explicit lock_guard(MutexTypes&... m);
117    lock_guard(MutexTypes&... m, adopt_lock_t);
118    ~lock_guard();
119    lock_guard(lock_guard const&) = delete;
120    lock_guard& operator=(lock_guard const&) = delete;
121private:
122    tuple<MutexTypes&...> pm; // exposition only
123};
124
125template <class Mutex>
126class unique_lock
127{
128public:
129    typedef Mutex mutex_type;
130    unique_lock() noexcept;
131    explicit unique_lock(mutex_type& m);
132    unique_lock(mutex_type& m, defer_lock_t) noexcept;
133    unique_lock(mutex_type& m, try_to_lock_t);
134    unique_lock(mutex_type& m, adopt_lock_t);
135    template <class Clock, class Duration>
136        unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
137    template <class Rep, class Period>
138        unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
139    ~unique_lock();
140
141    unique_lock(unique_lock const&) = delete;
142    unique_lock& operator=(unique_lock const&) = delete;
143
144    unique_lock(unique_lock&& u) noexcept;
145    unique_lock& operator=(unique_lock&& u) noexcept;
146
147    void lock();
148    bool try_lock();
149
150    template <class Rep, class Period>
151        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
152    template <class Clock, class Duration>
153        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
154
155    void unlock();
156
157    void swap(unique_lock& u) noexcept;
158    mutex_type* release() noexcept;
159
160    bool owns_lock() const noexcept;
161    explicit operator bool () const noexcept;
162    mutex_type* mutex() const noexcept;
163};
164
165template <class Mutex>
166  void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
167
168template <class L1, class L2, class... L3>
169  int try_lock(L1&, L2&, L3&...);
170template <class L1, class L2, class... L3>
171  void lock(L1&, L2&, L3&...);
172
173struct once_flag
174{
175    constexpr once_flag() noexcept;
176
177    once_flag(const once_flag&) = delete;
178    once_flag& operator=(const once_flag&) = delete;
179};
180
181template<class Callable, class ...Args>
182  void call_once(once_flag& flag, Callable&& func, Args&&... args);
183
184}  // std
185
186*/
187
188#include <__config>
189#include <__mutex_base>
190#include <functional>
191#include <memory>
192#ifndef _LIBCPP_HAS_NO_VARIADICS
193#include <tuple>
194#endif
195#include <__threading_support>
196
197#include <__undef_min_max>
198
199#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
200#pragma GCC system_header
201#endif
202
203_LIBCPP_BEGIN_NAMESPACE_STD
204
205#ifndef _LIBCPP_HAS_NO_THREADS
206
207class _LIBCPP_TYPE_VIS recursive_mutex
208{
209    __libcpp_mutex_t __m_;
210
211public:
212     recursive_mutex();
213     ~recursive_mutex();
214
215private:
216    recursive_mutex(const recursive_mutex&); // = delete;
217    recursive_mutex& operator=(const recursive_mutex&); // = delete;
218
219public:
220    void lock();
221    bool try_lock() _NOEXCEPT;
222    void unlock()  _NOEXCEPT;
223
224    typedef __libcpp_mutex_t* native_handle_type;
225    _LIBCPP_INLINE_VISIBILITY
226    native_handle_type native_handle() {return &__m_;}
227};
228
229class _LIBCPP_TYPE_VIS timed_mutex
230{
231    mutex              __m_;
232    condition_variable __cv_;
233    bool               __locked_;
234public:
235     timed_mutex();
236     ~timed_mutex();
237
238private:
239    timed_mutex(const timed_mutex&); // = delete;
240    timed_mutex& operator=(const timed_mutex&); // = delete;
241
242public:
243    void lock();
244    bool try_lock() _NOEXCEPT;
245    template <class _Rep, class _Period>
246        _LIBCPP_INLINE_VISIBILITY
247        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
248            {return try_lock_until(chrono::steady_clock::now() + __d);}
249    template <class _Clock, class _Duration>
250        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
251    void unlock() _NOEXCEPT;
252};
253
254template <class _Clock, class _Duration>
255bool
256timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
257{
258    using namespace chrono;
259    unique_lock<mutex> __lk(__m_);
260    bool no_timeout = _Clock::now() < __t;
261    while (no_timeout && __locked_)
262        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
263    if (!__locked_)
264    {
265        __locked_ = true;
266        return true;
267    }
268    return false;
269}
270
271class _LIBCPP_TYPE_VIS recursive_timed_mutex
272{
273    mutex              __m_;
274    condition_variable __cv_;
275    size_t             __count_;
276    __libcpp_thread_id __id_;
277public:
278     recursive_timed_mutex();
279     ~recursive_timed_mutex();
280
281private:
282    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
283    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
284
285public:
286    void lock();
287    bool try_lock() _NOEXCEPT;
288    template <class _Rep, class _Period>
289        _LIBCPP_INLINE_VISIBILITY
290        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
291            {return try_lock_until(chrono::steady_clock::now() + __d);}
292    template <class _Clock, class _Duration>
293        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
294    void unlock() _NOEXCEPT;
295};
296
297template <class _Clock, class _Duration>
298bool
299recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
300{
301    using namespace chrono;
302    __libcpp_thread_id __id = __libcpp_thread_get_current_id();
303    unique_lock<mutex> lk(__m_);
304    if (__libcpp_thread_id_equal(__id, __id_))
305    {
306        if (__count_ == numeric_limits<size_t>::max())
307            return false;
308        ++__count_;
309        return true;
310    }
311    bool no_timeout = _Clock::now() < __t;
312    while (no_timeout && __count_ != 0)
313        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
314    if (__count_ == 0)
315    {
316        __count_ = 1;
317        __id_ = __id;
318        return true;
319    }
320    return false;
321}
322
323template <class _L0, class _L1>
324int
325try_lock(_L0& __l0, _L1& __l1)
326{
327    unique_lock<_L0> __u0(__l0, try_to_lock);
328    if (__u0.owns_lock())
329    {
330        if (__l1.try_lock())
331        {
332            __u0.release();
333            return -1;
334        }
335        else
336            return 1;
337    }
338    return 0;
339}
340
341#ifndef _LIBCPP_HAS_NO_VARIADICS
342
343template <class _L0, class _L1, class _L2, class... _L3>
344int
345try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
346{
347    int __r = 0;
348    unique_lock<_L0> __u0(__l0, try_to_lock);
349    if (__u0.owns_lock())
350    {
351        __r = try_lock(__l1, __l2, __l3...);
352        if (__r == -1)
353            __u0.release();
354        else
355            ++__r;
356    }
357    return __r;
358}
359
360#endif  // _LIBCPP_HAS_NO_VARIADICS
361
362template <class _L0, class _L1>
363void
364lock(_L0& __l0, _L1& __l1)
365{
366    while (true)
367    {
368        {
369            unique_lock<_L0> __u0(__l0);
370            if (__l1.try_lock())
371            {
372                __u0.release();
373                break;
374            }
375        }
376        __libcpp_thread_yield();
377        {
378            unique_lock<_L1> __u1(__l1);
379            if (__l0.try_lock())
380            {
381                __u1.release();
382                break;
383            }
384        }
385        __libcpp_thread_yield();
386    }
387}
388
389#ifndef _LIBCPP_HAS_NO_VARIADICS
390
391template <class _L0, class _L1, class _L2, class ..._L3>
392void
393__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
394{
395    while (true)
396    {
397        switch (__i)
398        {
399        case 0:
400            {
401                unique_lock<_L0> __u0(__l0);
402                __i = try_lock(__l1, __l2, __l3...);
403                if (__i == -1)
404                {
405                    __u0.release();
406                    return;
407                }
408            }
409            ++__i;
410            __libcpp_thread_yield();
411            break;
412        case 1:
413            {
414                unique_lock<_L1> __u1(__l1);
415                __i = try_lock(__l2, __l3..., __l0);
416                if (__i == -1)
417                {
418                    __u1.release();
419                    return;
420                }
421            }
422            if (__i == sizeof...(_L3) + 1)
423                __i = 0;
424            else
425                __i += 2;
426            __libcpp_thread_yield();
427            break;
428        default:
429            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
430            return;
431        }
432    }
433}
434
435template <class _L0, class _L1, class _L2, class ..._L3>
436inline _LIBCPP_INLINE_VISIBILITY
437void
438lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
439{
440    __lock_first(0, __l0, __l1, __l2, __l3...);
441}
442
443template <class _L0>
444inline _LIBCPP_INLINE_VISIBILITY
445void __unlock(_L0& __l0) {
446    __l0.unlock();
447}
448
449template <class _L0, class _L1>
450inline _LIBCPP_INLINE_VISIBILITY
451void __unlock(_L0& __l0, _L1& __l1) {
452    __l0.unlock();
453    __l1.unlock();
454}
455
456template <class _L0, class _L1, class _L2, class ..._L3>
457inline _LIBCPP_INLINE_VISIBILITY
458void __unlock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3) {
459    __l0.unlock();
460    __l1.unlock();
461    _VSTD::__unlock(__l2, __l3...);
462}
463
464#endif  // _LIBCPP_HAS_NO_VARIADICS
465
466#endif // !_LIBCPP_HAS_NO_THREADS
467
468struct _LIBCPP_TYPE_VIS_ONLY once_flag;
469
470#ifndef _LIBCPP_HAS_NO_VARIADICS
471
472template<class _Callable, class... _Args>
473_LIBCPP_INLINE_VISIBILITY
474void call_once(once_flag&, _Callable&&, _Args&&...);
475
476#else  // _LIBCPP_HAS_NO_VARIADICS
477
478template<class _Callable>
479_LIBCPP_INLINE_VISIBILITY
480void call_once(once_flag&, _Callable&);
481
482template<class _Callable>
483_LIBCPP_INLINE_VISIBILITY
484void call_once(once_flag&, const _Callable&);
485
486#endif  // _LIBCPP_HAS_NO_VARIADICS
487
488struct _LIBCPP_TYPE_VIS_ONLY once_flag
489{
490    _LIBCPP_INLINE_VISIBILITY
491    _LIBCPP_CONSTEXPR
492        once_flag() _NOEXCEPT : __state_(0) {}
493
494private:
495    once_flag(const once_flag&); // = delete;
496    once_flag& operator=(const once_flag&); // = delete;
497
498    unsigned long __state_;
499
500#ifndef _LIBCPP_HAS_NO_VARIADICS
501    template<class _Callable, class... _Args>
502    friend
503    void call_once(once_flag&, _Callable&&, _Args&&...);
504#else  // _LIBCPP_HAS_NO_VARIADICS
505    template<class _Callable>
506    friend
507    void call_once(once_flag&, _Callable&);
508
509    template<class _Callable>
510    friend
511    void call_once(once_flag&, const _Callable&);
512#endif  // _LIBCPP_HAS_NO_VARIADICS
513};
514
515#ifndef _LIBCPP_HAS_NO_VARIADICS
516
517template <class _Fp>
518class __call_once_param
519{
520    _Fp& __f_;
521public:
522    _LIBCPP_INLINE_VISIBILITY
523    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
524
525    _LIBCPP_INLINE_VISIBILITY
526    void operator()()
527    {
528        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
529        __execute(_Index());
530    }
531
532private:
533    template <size_t ..._Indices>
534    _LIBCPP_INLINE_VISIBILITY
535    void __execute(__tuple_indices<_Indices...>)
536    {
537        __invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
538    }
539};
540
541#else
542
543template <class _Fp>
544class __call_once_param
545{
546    _Fp& __f_;
547public:
548    _LIBCPP_INLINE_VISIBILITY
549    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
550
551    _LIBCPP_INLINE_VISIBILITY
552    void operator()()
553    {
554        __f_();
555    }
556};
557
558#endif
559
560template <class _Fp>
561void
562__call_once_proxy(void* __vp)
563{
564    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
565    (*__p)();
566}
567
568_LIBCPP_FUNC_VIS void __call_once(volatile unsigned long&, void*, void(*)(void*));
569
570#ifndef _LIBCPP_HAS_NO_VARIADICS
571
572template<class _Callable, class... _Args>
573inline _LIBCPP_INLINE_VISIBILITY
574void
575call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
576{
577    if (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
578    {
579        typedef tuple<_Callable&&, _Args&&...> _Gp;
580        _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
581        __call_once_param<_Gp> __p(__f);
582        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
583    }
584}
585
586#else  // _LIBCPP_HAS_NO_VARIADICS
587
588template<class _Callable>
589inline _LIBCPP_INLINE_VISIBILITY
590void
591call_once(once_flag& __flag, _Callable& __func)
592{
593    if (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
594    {
595        __call_once_param<_Callable> __p(__func);
596        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
597    }
598}
599
600template<class _Callable>
601inline _LIBCPP_INLINE_VISIBILITY
602void
603call_once(once_flag& __flag, const _Callable& __func)
604{
605    if (__flag.__state_ != ~0ul)
606    {
607        __call_once_param<const _Callable> __p(__func);
608        __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
609    }
610}
611
612#endif  // _LIBCPP_HAS_NO_VARIADICS
613
614
615#if defined(_LIBCPP_ABI_VARIADIC_LOCK_GUARD) \
616    && !defined(_LIBCPP_CXX03_LANG)
617template <>
618class _LIBCPP_TYPE_VIS_ONLY lock_guard<> {
619public:
620    explicit lock_guard() {}
621    ~lock_guard() = default;
622
623    _LIBCPP_INLINE_VISIBILITY
624    explicit lock_guard(adopt_lock_t) {}
625
626    lock_guard(lock_guard const&) = delete;
627    lock_guard& operator=(lock_guard const&) = delete;
628};
629
630template <class ..._MArgs>
631class _LIBCPP_TYPE_VIS_ONLY lock_guard
632{
633    static_assert(sizeof...(_MArgs) >= 2, "At least 2 lock types required");
634    typedef tuple<_MArgs&...> _MutexTuple;
635
636public:
637    _LIBCPP_INLINE_VISIBILITY
638    explicit lock_guard(_MArgs&... __margs)
639      : __t_(__margs...)
640    {
641        _VSTD::lock(__margs...);
642    }
643
644    _LIBCPP_INLINE_VISIBILITY
645    lock_guard(_MArgs&... __margs, adopt_lock_t)
646        : __t_(__margs...)
647    {
648    }
649
650    _LIBCPP_INLINE_VISIBILITY
651    ~lock_guard() {
652        typedef typename __make_tuple_indices<sizeof...(_MArgs)>::type _Indices;
653        __unlock_unpack(_Indices{}, __t_);
654    }
655
656    lock_guard(lock_guard const&) = delete;
657    lock_guard& operator=(lock_guard const&) = delete;
658
659private:
660    template <size_t ..._Indx>
661    _LIBCPP_INLINE_VISIBILITY
662    static void __unlock_unpack(__tuple_indices<_Indx...>, _MutexTuple& __mt) {
663        _VSTD::__unlock(_VSTD::get<_Indx>(__mt)...);
664    }
665
666    _MutexTuple __t_;
667};
668
669#endif // _LIBCPP_ABI_VARIADIC_LOCK_GUARD
670
671_LIBCPP_END_NAMESPACE_STD
672
673#endif  // _LIBCPP_MUTEX
674