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