xref: /minix3/external/bsd/libc++/dist/libcxx/include/mutex (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7) 
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 Mutex>
113class unique_lock
114{
115public:
116    typedef Mutex mutex_type;
117    unique_lock() noexcept;
118    explicit unique_lock(mutex_type& m);
119    unique_lock(mutex_type& m, defer_lock_t) noexcept;
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) noexcept;
132    unique_lock& operator=(unique_lock&& u) noexcept;
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) noexcept;
145    mutex_type* release() noexcept;
146
147    bool owns_lock() const noexcept;
148    explicit operator bool () const noexcept;
149    mutex_type* mutex() const noexcept;
150};
151
152template <class Mutex>
153  void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
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() noexcept;
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#if !defined(_LIBCPP_HAS_NO_THREADS) && defined(__minix)
177#include <__mutex_base>
178#endif // !defined(_LIBCPP_HAS_NO_THREADS) && defined(__minix)
179#include <functional>
180#include <memory>
181#ifndef _LIBCPP_HAS_NO_VARIADICS
182#include <tuple>
183#endif
184#include <sched.h>
185
186#include <__undef_min_max>
187
188#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
189#pragma GCC system_header
190#endif
191
192_LIBCPP_BEGIN_NAMESPACE_STD
193
194#ifndef _LIBCPP_HAS_NO_THREADS
195
196class _LIBCPP_TYPE_VIS recursive_mutex
197{
198    pthread_mutex_t __m_;
199
200public:
201     recursive_mutex();
202     ~recursive_mutex();
203
204private:
205    recursive_mutex(const recursive_mutex&); // = delete;
206    recursive_mutex& operator=(const recursive_mutex&); // = delete;
207
208public:
209    void lock();
210    bool try_lock() _NOEXCEPT;
211    void unlock()  _NOEXCEPT;
212
213    typedef pthread_mutex_t* native_handle_type;
214    _LIBCPP_INLINE_VISIBILITY
215    native_handle_type native_handle() {return &__m_;}
216};
217
218class _LIBCPP_TYPE_VIS timed_mutex
219{
220    mutex              __m_;
221    condition_variable __cv_;
222    bool               __locked_;
223public:
224     timed_mutex();
225     ~timed_mutex();
226
227private:
228    timed_mutex(const timed_mutex&); // = delete;
229    timed_mutex& operator=(const timed_mutex&); // = delete;
230
231public:
232    void lock();
233    bool try_lock() _NOEXCEPT;
234    template <class _Rep, class _Period>
235        _LIBCPP_INLINE_VISIBILITY
236        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
237            {return try_lock_until(chrono::steady_clock::now() + __d);}
238    template <class _Clock, class _Duration>
239        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
240    void unlock() _NOEXCEPT;
241};
242
243template <class _Clock, class _Duration>
244bool
245timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
246{
247    using namespace chrono;
248    unique_lock<mutex> __lk(__m_);
249    bool no_timeout = _Clock::now() < __t;
250    while (no_timeout && __locked_)
251        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
252    if (!__locked_)
253    {
254        __locked_ = true;
255        return true;
256    }
257    return false;
258}
259
260class _LIBCPP_TYPE_VIS recursive_timed_mutex
261{
262    mutex              __m_;
263    condition_variable __cv_;
264    size_t             __count_;
265    pthread_t          __id_;
266public:
267     recursive_timed_mutex();
268     ~recursive_timed_mutex();
269
270private:
271    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
272    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
273
274public:
275    void lock();
276    bool try_lock() _NOEXCEPT;
277    template <class _Rep, class _Period>
278        _LIBCPP_INLINE_VISIBILITY
279        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
280            {return try_lock_until(chrono::steady_clock::now() + __d);}
281    template <class _Clock, class _Duration>
282        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
283    void unlock() _NOEXCEPT;
284};
285
286template <class _Clock, class _Duration>
287bool
288recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
289{
290    using namespace chrono;
291    pthread_t __id = pthread_self();
292    unique_lock<mutex> lk(__m_);
293    if (pthread_equal(__id, __id_))
294    {
295        if (__count_ == numeric_limits<size_t>::max())
296            return false;
297        ++__count_;
298        return true;
299    }
300    bool no_timeout = _Clock::now() < __t;
301    while (no_timeout && __count_ != 0)
302        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
303    if (__count_ == 0)
304    {
305        __count_ = 1;
306        __id_ = __id;
307        return true;
308    }
309    return false;
310}
311
312template <class _L0, class _L1>
313int
314try_lock(_L0& __l0, _L1& __l1)
315{
316    unique_lock<_L0> __u0(__l0, try_to_lock);
317    if (__u0.owns_lock())
318    {
319        if (__l1.try_lock())
320        {
321            __u0.release();
322            return -1;
323        }
324        else
325            return 1;
326    }
327    return 0;
328}
329
330#ifndef _LIBCPP_HAS_NO_VARIADICS
331
332template <class _L0, class _L1, class _L2, class... _L3>
333int
334try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
335{
336    int __r = 0;
337    unique_lock<_L0> __u0(__l0, try_to_lock);
338    if (__u0.owns_lock())
339    {
340        __r = try_lock(__l1, __l2, __l3...);
341        if (__r == -1)
342            __u0.release();
343        else
344            ++__r;
345    }
346    return __r;
347}
348
349#endif  // _LIBCPP_HAS_NO_VARIADICS
350
351template <class _L0, class _L1>
352void
353lock(_L0& __l0, _L1& __l1)
354{
355    while (true)
356    {
357        {
358            unique_lock<_L0> __u0(__l0);
359            if (__l1.try_lock())
360            {
361                __u0.release();
362                break;
363            }
364        }
365        sched_yield();
366        {
367            unique_lock<_L1> __u1(__l1);
368            if (__l0.try_lock())
369            {
370                __u1.release();
371                break;
372            }
373        }
374        sched_yield();
375    }
376}
377
378#ifndef _LIBCPP_HAS_NO_VARIADICS
379
380template <class _L0, class _L1, class _L2, class ..._L3>
381void
382__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
383{
384    while (true)
385    {
386        switch (__i)
387        {
388        case 0:
389            {
390                unique_lock<_L0> __u0(__l0);
391                __i = try_lock(__l1, __l2, __l3...);
392                if (__i == -1)
393                {
394                    __u0.release();
395                    return;
396                }
397            }
398            ++__i;
399            sched_yield();
400            break;
401        case 1:
402            {
403                unique_lock<_L1> __u1(__l1);
404                __i = try_lock(__l2, __l3..., __l0);
405                if (__i == -1)
406                {
407                    __u1.release();
408                    return;
409                }
410            }
411            if (__i == sizeof...(_L3) + 1)
412                __i = 0;
413            else
414                __i += 2;
415            sched_yield();
416            break;
417        default:
418            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
419            return;
420        }
421    }
422}
423
424template <class _L0, class _L1, class _L2, class ..._L3>
425inline _LIBCPP_INLINE_VISIBILITY
426void
427lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
428{
429    __lock_first(0, __l0, __l1, __l2, __l3...);
430}
431
432#endif  // _LIBCPP_HAS_NO_VARIADICS
433
434#endif // !_LIBCPP_HAS_NO_THREADS
435
436struct _LIBCPP_TYPE_VIS_ONLY once_flag;
437
438#ifndef _LIBCPP_HAS_NO_VARIADICS
439
440template<class _Callable, class... _Args>
441_LIBCPP_INLINE_VISIBILITY
442void call_once(once_flag&, _Callable&&, _Args&&...);
443
444#else  // _LIBCPP_HAS_NO_VARIADICS
445
446template<class _Callable>
447_LIBCPP_INLINE_VISIBILITY
448void call_once(once_flag&, _Callable&);
449
450template<class _Callable>
451_LIBCPP_INLINE_VISIBILITY
452void call_once(once_flag&, const _Callable&);
453
454#endif  // _LIBCPP_HAS_NO_VARIADICS
455
456struct _LIBCPP_TYPE_VIS_ONLY once_flag
457{
458    _LIBCPP_INLINE_VISIBILITY
459    _LIBCPP_CONSTEXPR
460        once_flag() _NOEXCEPT : __state_(0) {}
461
462private:
463    once_flag(const once_flag&); // = delete;
464    once_flag& operator=(const once_flag&); // = delete;
465
466    unsigned long __state_;
467
468#ifndef _LIBCPP_HAS_NO_VARIADICS
469    template<class _Callable, class... _Args>
470    friend
471    void call_once(once_flag&, _Callable&&, _Args&&...);
472#else  // _LIBCPP_HAS_NO_VARIADICS
473    template<class _Callable>
474    friend
475    void call_once(once_flag&, _Callable&);
476
477    template<class _Callable>
478    friend
479    void call_once(once_flag&, const _Callable&);
480#endif  // _LIBCPP_HAS_NO_VARIADICS
481};
482
483#ifndef _LIBCPP_HAS_NO_VARIADICS
484
485template <class _Fp>
486class __call_once_param
487{
488    _Fp& __f_;
489public:
490    _LIBCPP_INLINE_VISIBILITY
491    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
492
493    _LIBCPP_INLINE_VISIBILITY
494    void operator()()
495    {
496        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
497        __execute(_Index());
498    }
499
500private:
501    template <size_t ..._Indices>
502    _LIBCPP_INLINE_VISIBILITY
503    void __execute(__tuple_indices<_Indices...>)
504    {
505        __invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
506    }
507};
508
509#else
510
511template <class _Fp>
512class __call_once_param
513{
514    _Fp& __f_;
515public:
516    _LIBCPP_INLINE_VISIBILITY
517    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
518
519    _LIBCPP_INLINE_VISIBILITY
520    void operator()()
521    {
522        __f_();
523    }
524};
525
526#endif
527
528template <class _Fp>
529void
530__call_once_proxy(void* __vp)
531{
532    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
533    (*__p)();
534}
535
536_LIBCPP_FUNC_VIS void __call_once(volatile unsigned long&, void*, void(*)(void*));
537
538#ifndef _LIBCPP_HAS_NO_VARIADICS
539
540template<class _Callable, class... _Args>
541inline _LIBCPP_INLINE_VISIBILITY
542void
543call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
544{
545    if (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
546    {
547        typedef tuple<_Callable&&, _Args&&...> _Gp;
548        _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
549        __call_once_param<_Gp> __p(__f);
550        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
551    }
552}
553
554#else  // _LIBCPP_HAS_NO_VARIADICS
555
556template<class _Callable>
557inline _LIBCPP_INLINE_VISIBILITY
558void
559call_once(once_flag& __flag, _Callable& __func)
560{
561    if (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
562    {
563        __call_once_param<_Callable> __p(__func);
564        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
565    }
566}
567
568template<class _Callable>
569inline _LIBCPP_INLINE_VISIBILITY
570void
571call_once(once_flag& __flag, const _Callable& __func)
572{
573    if (__flag.__state_ != ~0ul)
574    {
575        __call_once_param<const _Callable> __p(__func);
576        __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
577    }
578}
579
580#endif  // _LIBCPP_HAS_NO_VARIADICS
581
582_LIBCPP_END_NAMESPACE_STD
583
584#endif  // _LIBCPP_MUTEX
585