mutex revision 360784 
1// -*- C++ -*-
2//===--------------------------- mutex ------------------------------------===//
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;  // If MutexTypes... consists of the single type Mutex
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 <cstdint>
192#include <functional>
193#include <memory>
194#ifndef _LIBCPP_CXX03_LANG
195#include <tuple>
196#endif
197#include <version>
198#include <__threading_support>
199
200#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
201#pragma GCC system_header
202#endif
203
204_LIBCPP_PUSH_MACROS
205#include <__undef_macros>
206
207
208_LIBCPP_BEGIN_NAMESPACE_STD
209
210#ifndef _LIBCPP_HAS_NO_THREADS
211
212class _LIBCPP_TYPE_VIS recursive_mutex
213{
214    __libcpp_recursive_mutex_t __m_;
215
216public:
217     recursive_mutex();
218     ~recursive_mutex();
219
220private:
221    recursive_mutex(const recursive_mutex&); // = delete;
222    recursive_mutex& operator=(const recursive_mutex&); // = delete;
223
224public:
225    void lock();
226    bool try_lock() _NOEXCEPT;
227    void unlock()  _NOEXCEPT;
228
229    typedef __libcpp_recursive_mutex_t* native_handle_type;
230
231    _LIBCPP_INLINE_VISIBILITY
232    native_handle_type native_handle() {return &__m_;}
233};
234
235class _LIBCPP_TYPE_VIS timed_mutex
236{
237    mutex              __m_;
238    condition_variable __cv_;
239    bool               __locked_;
240public:
241     timed_mutex();
242     ~timed_mutex();
243
244private:
245    timed_mutex(const timed_mutex&); // = delete;
246    timed_mutex& operator=(const timed_mutex&); // = delete;
247
248public:
249    void lock();
250    bool try_lock() _NOEXCEPT;
251    template <class _Rep, class _Period>
252        _LIBCPP_INLINE_VISIBILITY
253        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
254            {return try_lock_until(chrono::steady_clock::now() + __d);}
255    template <class _Clock, class _Duration>
256        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
257        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
258    void unlock() _NOEXCEPT;
259};
260
261template <class _Clock, class _Duration>
262bool
263timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
264{
265    using namespace chrono;
266    unique_lock<mutex> __lk(__m_);
267    bool no_timeout = _Clock::now() < __t;
268    while (no_timeout && __locked_)
269        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
270    if (!__locked_)
271    {
272        __locked_ = true;
273        return true;
274    }
275    return false;
276}
277
278class _LIBCPP_TYPE_VIS recursive_timed_mutex
279{
280    mutex              __m_;
281    condition_variable __cv_;
282    size_t             __count_;
283    __thread_id        __id_;
284public:
285     recursive_timed_mutex();
286     ~recursive_timed_mutex();
287
288private:
289    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
290    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
291
292public:
293    void lock();
294    bool try_lock() _NOEXCEPT;
295    template <class _Rep, class _Period>
296        _LIBCPP_INLINE_VISIBILITY
297        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
298            {return try_lock_until(chrono::steady_clock::now() + __d);}
299    template <class _Clock, class _Duration>
300        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
301        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
302    void unlock() _NOEXCEPT;
303};
304
305template <class _Clock, class _Duration>
306bool
307recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
308{
309    using namespace chrono;
310    __thread_id __id = this_thread::get_id();
311    unique_lock<mutex> lk(__m_);
312    if (__id == __id_)
313    {
314        if (__count_ == numeric_limits<size_t>::max())
315            return false;
316        ++__count_;
317        return true;
318    }
319    bool no_timeout = _Clock::now() < __t;
320    while (no_timeout && __count_ != 0)
321        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
322    if (__count_ == 0)
323    {
324        __count_ = 1;
325        __id_ = __id;
326        return true;
327    }
328    return false;
329}
330
331template <class _L0, class _L1>
332int
333try_lock(_L0& __l0, _L1& __l1)
334{
335    unique_lock<_L0> __u0(__l0, try_to_lock);
336    if (__u0.owns_lock())
337    {
338        if (__l1.try_lock())
339        {
340            __u0.release();
341            return -1;
342        }
343        else
344            return 1;
345    }
346    return 0;
347}
348
349#ifndef _LIBCPP_CXX03_LANG
350
351template <class _L0, class _L1, class _L2, class... _L3>
352int
353try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
354{
355    int __r = 0;
356    unique_lock<_L0> __u0(__l0, try_to_lock);
357    if (__u0.owns_lock())
358    {
359        __r = try_lock(__l1, __l2, __l3...);
360        if (__r == -1)
361            __u0.release();
362        else
363            ++__r;
364    }
365    return __r;
366}
367
368#endif  // _LIBCPP_CXX03_LANG
369
370template <class _L0, class _L1>
371void
372lock(_L0& __l0, _L1& __l1)
373{
374    while (true)
375    {
376        {
377            unique_lock<_L0> __u0(__l0);
378            if (__l1.try_lock())
379            {
380                __u0.release();
381                break;
382            }
383        }
384        __libcpp_thread_yield();
385        {
386            unique_lock<_L1> __u1(__l1);
387            if (__l0.try_lock())
388            {
389                __u1.release();
390                break;
391            }
392        }
393        __libcpp_thread_yield();
394    }
395}
396
397#ifndef _LIBCPP_CXX03_LANG
398
399template <class _L0, class _L1, class _L2, class ..._L3>
400void
401__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
402{
403    while (true)
404    {
405        switch (__i)
406        {
407        case 0:
408            {
409                unique_lock<_L0> __u0(__l0);
410                __i = try_lock(__l1, __l2, __l3...);
411                if (__i == -1)
412                {
413                    __u0.release();
414                    return;
415                }
416            }
417            ++__i;
418            __libcpp_thread_yield();
419            break;
420        case 1:
421            {
422                unique_lock<_L1> __u1(__l1);
423                __i = try_lock(__l2, __l3..., __l0);
424                if (__i == -1)
425                {
426                    __u1.release();
427                    return;
428                }
429            }
430            if (__i == sizeof...(_L3) + 1)
431                __i = 0;
432            else
433                __i += 2;
434            __libcpp_thread_yield();
435            break;
436        default:
437            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
438            return;
439        }
440    }
441}
442
443template <class _L0, class _L1, class _L2, class ..._L3>
444inline _LIBCPP_INLINE_VISIBILITY
445void
446lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
447{
448    __lock_first(0, __l0, __l1, __l2, __l3...);
449}
450
451template <class _L0>
452inline _LIBCPP_INLINE_VISIBILITY
453void __unlock(_L0& __l0) {
454    __l0.unlock();
455}
456
457template <class _L0, class _L1>
458inline _LIBCPP_INLINE_VISIBILITY
459void __unlock(_L0& __l0, _L1& __l1) {
460    __l0.unlock();
461    __l1.unlock();
462}
463
464template <class _L0, class _L1, class _L2, class ..._L3>
465inline _LIBCPP_INLINE_VISIBILITY
466void __unlock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3) {
467    __l0.unlock();
468    __l1.unlock();
469    _VSTD::__unlock(__l2, __l3...);
470}
471
472#endif  // _LIBCPP_CXX03_LANG
473
474#if _LIBCPP_STD_VER > 14
475template <class ..._Mutexes>
476class _LIBCPP_TEMPLATE_VIS scoped_lock;
477
478template <>
479class _LIBCPP_TEMPLATE_VIS scoped_lock<> {
480public:
481    explicit scoped_lock() {}
482    ~scoped_lock() = default;
483
484    _LIBCPP_INLINE_VISIBILITY
485    explicit scoped_lock(adopt_lock_t) {}
486
487    scoped_lock(scoped_lock const&) = delete;
488    scoped_lock& operator=(scoped_lock const&) = delete;
489};
490
491template <class _Mutex>
492class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable) scoped_lock<_Mutex> {
493public:
494    typedef _Mutex  mutex_type;
495private:
496    mutex_type& __m_;
497public:
498    explicit scoped_lock(mutex_type & __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
499        : __m_(__m) {__m_.lock();}
500
501    ~scoped_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
502
503    _LIBCPP_INLINE_VISIBILITY
504    explicit scoped_lock(adopt_lock_t, mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
505        : __m_(__m) {}
506
507    scoped_lock(scoped_lock const&) = delete;
508    scoped_lock& operator=(scoped_lock const&) = delete;
509};
510
511template <class ..._MArgs>
512class _LIBCPP_TEMPLATE_VIS scoped_lock
513{
514    static_assert(sizeof...(_MArgs) > 1, "At least 2 lock types required");
515    typedef tuple<_MArgs&...> _MutexTuple;
516
517public:
518    _LIBCPP_INLINE_VISIBILITY
519    explicit scoped_lock(_MArgs&... __margs)
520      : __t_(__margs...)
521    {
522        _VSTD::lock(__margs...);
523    }
524
525    _LIBCPP_INLINE_VISIBILITY
526    scoped_lock(adopt_lock_t, _MArgs&... __margs)
527        : __t_(__margs...)
528    {
529    }
530
531    _LIBCPP_INLINE_VISIBILITY
532    ~scoped_lock() {
533        typedef typename __make_tuple_indices<sizeof...(_MArgs)>::type _Indices;
534        __unlock_unpack(_Indices{}, __t_);
535    }
536
537    scoped_lock(scoped_lock const&) = delete;
538    scoped_lock& operator=(scoped_lock const&) = delete;
539
540private:
541    template <size_t ..._Indx>
542    _LIBCPP_INLINE_VISIBILITY
543    static void __unlock_unpack(__tuple_indices<_Indx...>, _MutexTuple& __mt) {
544        _VSTD::__unlock(_VSTD::get<_Indx>(__mt)...);
545    }
546
547    _MutexTuple __t_;
548};
549
550#endif // _LIBCPP_STD_VER > 14
551#endif // !_LIBCPP_HAS_NO_THREADS
552
553struct _LIBCPP_TEMPLATE_VIS once_flag;
554
555#ifndef _LIBCPP_CXX03_LANG
556
557template<class _Callable, class... _Args>
558_LIBCPP_INLINE_VISIBILITY
559void call_once(once_flag&, _Callable&&, _Args&&...);
560
561#else  // _LIBCPP_CXX03_LANG
562
563template<class _Callable>
564_LIBCPP_INLINE_VISIBILITY
565void call_once(once_flag&, _Callable&);
566
567template<class _Callable>
568_LIBCPP_INLINE_VISIBILITY
569void call_once(once_flag&, const _Callable&);
570
571#endif  // _LIBCPP_CXX03_LANG
572
573struct _LIBCPP_TEMPLATE_VIS once_flag
574{
575    _LIBCPP_INLINE_VISIBILITY
576    _LIBCPP_CONSTEXPR
577        once_flag() _NOEXCEPT : __state_(0) {}
578
579#if defined(_LIBCPP_ABI_MICROSOFT)
580   typedef uintptr_t _State_type;
581#else
582   typedef unsigned long _State_type;
583#endif
584
585
586private:
587    once_flag(const once_flag&); // = delete;
588    once_flag& operator=(const once_flag&); // = delete;
589
590    _State_type __state_;
591
592#ifndef _LIBCPP_CXX03_LANG
593    template<class _Callable, class... _Args>
594    friend
595    void call_once(once_flag&, _Callable&&, _Args&&...);
596#else  // _LIBCPP_CXX03_LANG
597    template<class _Callable>
598    friend
599    void call_once(once_flag&, _Callable&);
600
601    template<class _Callable>
602    friend
603    void call_once(once_flag&, const _Callable&);
604#endif  // _LIBCPP_CXX03_LANG
605};
606
607#ifndef _LIBCPP_CXX03_LANG
608
609template <class _Fp>
610class __call_once_param
611{
612    _Fp& __f_;
613public:
614    _LIBCPP_INLINE_VISIBILITY
615    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
616
617    _LIBCPP_INLINE_VISIBILITY
618    void operator()()
619    {
620        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
621        __execute(_Index());
622    }
623
624private:
625    template <size_t ..._Indices>
626    _LIBCPP_INLINE_VISIBILITY
627    void __execute(__tuple_indices<_Indices...>)
628    {
629        __invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
630    }
631};
632
633#else
634
635template <class _Fp>
636class __call_once_param
637{
638    _Fp& __f_;
639public:
640    _LIBCPP_INLINE_VISIBILITY
641    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
642
643    _LIBCPP_INLINE_VISIBILITY
644    void operator()()
645    {
646        __f_();
647    }
648};
649
650#endif
651
652template <class _Fp>
653void _LIBCPP_INLINE_VISIBILITY
654__call_once_proxy(void* __vp)
655{
656    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
657    (*__p)();
658}
659
660_LIBCPP_FUNC_VIS void __call_once(volatile once_flag::_State_type&, void*,
661                                  void (*)(void*));
662
663#ifndef _LIBCPP_CXX03_LANG
664
665template<class _Callable, class... _Args>
666inline _LIBCPP_INLINE_VISIBILITY
667void
668call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
669{
670    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
671    {
672        typedef tuple<_Callable&&, _Args&&...> _Gp;
673        _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
674        __call_once_param<_Gp> __p(__f);
675        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
676    }
677}
678
679#else  // _LIBCPP_CXX03_LANG
680
681template<class _Callable>
682inline _LIBCPP_INLINE_VISIBILITY
683void
684call_once(once_flag& __flag, _Callable& __func)
685{
686    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
687    {
688        __call_once_param<_Callable> __p(__func);
689        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
690    }
691}
692
693template<class _Callable>
694inline _LIBCPP_INLINE_VISIBILITY
695void
696call_once(once_flag& __flag, const _Callable& __func)
697{
698    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
699    {
700        __call_once_param<const _Callable> __p(__func);
701        __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
702    }
703}
704
705#endif  // _LIBCPP_CXX03_LANG
706
707_LIBCPP_END_NAMESPACE_STD
708
709_LIBCPP_POP_MACROS
710
711#endif  // _LIBCPP_MUTEX
712