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