xref: /llvm-project-15.0.7/libcxx/include/mutex (revision 2356b2c3) 
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     mutex();
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();
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();
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 Mutex>
113class unique_lock
114{
115public:
116    typedef Mutex mutex_type;
117    unique_lock();
118    explicit unique_lock(mutex_type& m);
119    unique_lock(mutex_type& m, defer_lock_t);
120    unique_lock(mutex_type& m, try_to_lock_t);
121    unique_lock(mutex_type& m, adopt_lock_t);
122    template <class Clock, class Duration>
123        unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
124    template <class Rep, class Period>
125        unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
126    ~unique_lock();
127
128    unique_lock(unique_lock const&) = delete;
129    unique_lock& operator=(unique_lock const&) = delete;
130
131    unique_lock(unique_lock&& u);
132    unique_lock& operator=(unique_lock&& u);
133
134    void lock();
135    bool try_lock();
136
137    template <class Rep, class Period>
138        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
139    template <class Clock, class Duration>
140        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
141
142    void unlock();
143
144    void swap(unique_lock& u);
145    mutex_type* release();
146
147    bool owns_lock() const;
148    explicit operator bool () const;
149    mutex_type* mutex() const;
150};
151
152template <class Mutex>
153  void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y);
154
155template <class L1, class L2, class... L3>
156  int try_lock(L1&, L2&, L3&...);
157template <class L1, class L2, class... L3>
158  void lock(L1&, L2&, L3&...);
159
160struct once_flag
161{
162    constexpr once_flag();
163
164    once_flag(const once_flag&) = delete;
165    once_flag& operator=(const once_flag&) = delete;
166};
167
168template<class Callable, class ...Args>
169  void call_once(once_flag& flag, Callable&& func, Args&&... args);
170
171}  // std
172
173*/
174
175#include <__config>
176#include <__mutex_base>
177#include <functional>
178#ifndef _LIBCPP_HAS_NO_VARIADICS
179#include <tuple>
180#endif
181
182#pragma GCC system_header
183
184_LIBCPP_BEGIN_NAMESPACE_STD
185
186class _LIBCPP_VISIBLE recursive_mutex
187{
188    pthread_mutex_t __m_;
189
190public:
191     recursive_mutex();
192     ~recursive_mutex();
193
194private:
195    recursive_mutex(const recursive_mutex&); // = delete;
196    recursive_mutex& operator=(const recursive_mutex&); // = delete;
197
198public:
199    void lock();
200    bool try_lock();
201    void unlock();
202
203    typedef pthread_mutex_t* native_handle_type;
204    _LIBCPP_INLINE_VISIBILITY
205    native_handle_type native_handle() {return &__m_;}
206};
207
208class _LIBCPP_VISIBLE timed_mutex
209{
210    mutex              __m_;
211    condition_variable __cv_;
212    bool               __locked_;
213public:
214     timed_mutex();
215     ~timed_mutex();
216
217private:
218    timed_mutex(const timed_mutex&); // = delete;
219    timed_mutex& operator=(const timed_mutex&); // = delete;
220
221public:
222    void lock();
223    bool try_lock();
224    template <class _Rep, class _Period>
225        _LIBCPP_INLINE_VISIBILITY
226        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
227            {return try_lock_until(chrono::steady_clock::now() + __d);}
228    template <class _Clock, class _Duration>
229        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
230    void unlock();
231};
232
233template <class _Clock, class _Duration>
234bool
235timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
236{
237    using namespace chrono;
238    unique_lock<mutex> __lk(__m_);
239    bool no_timeout = _Clock::now() < __t;
240    while (no_timeout && __locked_)
241        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
242    if (!__locked_)
243    {
244        __locked_ = true;
245        return true;
246    }
247    return false;
248}
249
250class _LIBCPP_VISIBLE recursive_timed_mutex
251{
252    mutex              __m_;
253    condition_variable __cv_;
254    size_t             __count_;
255    pthread_t          __id_;
256public:
257     recursive_timed_mutex();
258     ~recursive_timed_mutex();
259
260private:
261    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
262    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
263
264public:
265    void lock();
266    bool try_lock();
267    template <class _Rep, class _Period>
268        _LIBCPP_INLINE_VISIBILITY
269        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
270            {return try_lock_until(chrono::steady_clock::now() + __d);}
271    template <class _Clock, class _Duration>
272        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
273    void unlock();
274};
275
276template <class _Clock, class _Duration>
277bool
278recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
279{
280    using namespace chrono;
281    pthread_t __id = pthread_self();
282    unique_lock<mutex> lk(__m_);
283    if (pthread_equal(__id, __id_))
284    {
285        if (__count_ == numeric_limits<size_t>::max())
286            return false;
287        ++__count_;
288        return true;
289    }
290    bool no_timeout = _Clock::now() < __t;
291    while (no_timeout && __count_ != 0)
292        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
293    if (__count_ == 0)
294    {
295        __count_ = 1;
296        __id_ = __id;
297        return true;
298    }
299    return false;
300}
301
302template <class _L0, class _L1>
303int
304try_lock(_L0& __l0, _L1& __l1)
305{
306    unique_lock<_L0> __u0(__l0, try_to_lock);
307    if (__u0.owns_lock())
308    {
309        if (__l1.try_lock())
310        {
311            __u0.release();
312            return -1;
313        }
314        else
315            return 1;
316    }
317    return 0;
318}
319
320#ifndef _LIBCPP_HAS_NO_VARIADICS
321
322template <class _L0, class _L1, class _L2, class... _L3>
323int
324try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
325{
326    int __r = 0;
327    unique_lock<_L0> __u0(__l0, try_to_lock);
328    if (__u0.owns_lock())
329    {
330        __r = try_lock(__l1, __l2, __l3...);
331        if (__r == -1)
332            __u0.release();
333        else
334            ++__r;
335    }
336    return __r;
337}
338
339#endif  // _LIBCPP_HAS_NO_VARIADICS
340
341template <class _L0, class _L1>
342void
343lock(_L0& __l0, _L1& __l1)
344{
345    while (true)
346    {
347        {
348            unique_lock<_L0> __u0(__l0);
349            if (__l1.try_lock())
350            {
351                __u0.release();
352                break;
353            }
354        }
355        sched_yield();
356        {
357            unique_lock<_L1> __u1(__l1);
358            if (__l0.try_lock())
359            {
360                __u1.release();
361                break;
362            }
363        }
364        sched_yield();
365    }
366}
367
368#ifndef _LIBCPP_HAS_NO_VARIADICS
369
370template <class _L0, class _L1, class _L2, class ..._L3>
371void
372__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
373{
374    while (true)
375    {
376        switch (__i)
377        {
378        case 0:
379            {
380                unique_lock<_L0> __u0(__l0);
381                __i = try_lock(__l1, __l2, __l3...);
382                if (__i == -1)
383                {
384                    __u0.release();
385                    return;
386                }
387            }
388            ++__i;
389            sched_yield();
390            break;
391        case 1:
392            {
393                unique_lock<_L1> __u1(__l1);
394                __i = try_lock(__l2, __l3..., __l0);
395                if (__i == -1)
396                {
397                    __u1.release();
398                    return;
399                }
400            }
401            if (__i == sizeof...(_L3) + 1)
402                __i = 0;
403            else
404                __i += 2;
405            sched_yield();
406            break;
407        default:
408            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
409            return;
410        }
411    }
412}
413
414template <class _L0, class _L1, class _L2, class ..._L3>
415inline _LIBCPP_INLINE_VISIBILITY
416void
417lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
418{
419    __lock_first(0, __l0, __l1, __l2, __l3...);
420}
421
422#endif  // _LIBCPP_HAS_NO_VARIADICS
423
424struct once_flag;
425
426#ifndef _LIBCPP_HAS_NO_VARIADICS
427
428template<class _Callable, class... _Args>
429  void call_once(once_flag&, _Callable&&, _Args&&...);
430
431#else  // _LIBCPP_HAS_NO_VARIADICS
432
433template<class _Callable>
434  void call_once(once_flag&, _Callable);
435
436#endif  // _LIBCPP_HAS_NO_VARIADICS
437
438struct _LIBCPP_VISIBLE once_flag
439{
440    _LIBCPP_INLINE_VISIBILITY
441    // constexpr
442        once_flag() {}
443
444private:
445    once_flag(const once_flag&); // = delete;
446    once_flag& operator=(const once_flag&); // = delete;
447
448    unsigned long __state_;
449
450#ifndef _LIBCPP_HAS_NO_VARIADICS
451    template<class _Callable, class... _Args>
452    friend
453    void call_once(once_flag&, _Callable&&, _Args&&...);
454#else  // _LIBCPP_HAS_NO_VARIADICS
455    template<class _Callable>
456    friend
457    void call_once(once_flag&, _Callable);
458#endif  // _LIBCPP_HAS_NO_VARIADICS
459};
460
461#ifndef _LIBCPP_HAS_NO_VARIADICS
462
463template <class _F>
464class __call_once_param
465{
466    _F __f_;
467public:
468#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
469    _LIBCPP_INLINE_VISIBILITY
470    explicit __call_once_param(_F&& __f) : __f_(_VSTD::move(__f)) {}
471#else
472    _LIBCPP_INLINE_VISIBILITY
473    explicit __call_once_param(const _F& __f) : __f_(__f) {}
474#endif
475
476    _LIBCPP_INLINE_VISIBILITY
477    void operator()()
478    {
479        typedef typename __make_tuple_indices<tuple_size<_F>::value, 1>::type _Index;
480        __execute(_Index());
481    }
482
483private:
484    template <size_t ..._Indices>
485    _LIBCPP_INLINE_VISIBILITY
486    void __execute(__tuple_indices<_Indices...>)
487    {
488        __invoke(_VSTD::move(_VSTD::get<0>(__f_)), _VSTD::move(_VSTD::get<_Indices>(__f_))...);
489    }
490};
491
492#else
493
494template <class _F>
495class __call_once_param
496{
497    _F __f_;
498public:
499#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
500    _LIBCPP_INLINE_VISIBILITY
501    explicit __call_once_param(_F&& __f) : __f_(_VSTD::move(__f)) {}
502#else
503    _LIBCPP_INLINE_VISIBILITY
504    explicit __call_once_param(const _F& __f) : __f_(__f) {}
505#endif
506
507    _LIBCPP_INLINE_VISIBILITY
508    void operator()()
509    {
510        __f_();
511    }
512};
513
514#endif
515
516template <class _F>
517void
518__call_once_proxy(void* __vp)
519{
520    __call_once_param<_F>* __p = static_cast<__call_once_param<_F>*>(__vp);
521    (*__p)();
522}
523
524void __call_once(volatile unsigned long&, void*, void(*)(void*));
525
526#ifndef _LIBCPP_HAS_NO_VARIADICS
527
528template<class _Callable, class... _Args>
529inline _LIBCPP_INLINE_VISIBILITY
530void
531call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
532{
533    if (__builtin_expect(__flag.__state_ , ~0ul) != ~0ul)
534    {
535        typedef tuple<typename decay<_Callable>::type, typename decay<_Args>::type...> _G;
536        __call_once_param<_G> __p(_G(__decay_copy(_VSTD::forward<_Callable>(__func)),
537                                __decay_copy(_VSTD::forward<_Args>(__args))...));
538        __call_once(__flag.__state_, &__p, &__call_once_proxy<_G>);
539    }
540}
541
542#else  // _LIBCPP_HAS_NO_VARIADICS
543
544template<class _Callable>
545inline _LIBCPP_INLINE_VISIBILITY
546void
547call_once(once_flag& __flag, _Callable __func)
548{
549    if (__flag.__state_ != ~0ul)
550    {
551        __call_once_param<_Callable> __p(__func);
552        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
553    }
554}
555
556#endif  // _LIBCPP_HAS_NO_VARIADICS
557
558_LIBCPP_END_NAMESPACE_STD
559
560#endif  // _LIBCPP_MUTEX
561