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