mutex revision 262801 
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
190class _LIBCPP_TYPE_VIS recursive_mutex
191{
192    pthread_mutex_t __m_;
193
194public:
195     recursive_mutex();
196     ~recursive_mutex();
197
198private:
199    recursive_mutex(const recursive_mutex&); // = delete;
200    recursive_mutex& operator=(const recursive_mutex&); // = delete;
201
202public:
203    void lock();
204    bool try_lock() _NOEXCEPT;
205    void unlock()  _NOEXCEPT;
206
207    typedef pthread_mutex_t* native_handle_type;
208    _LIBCPP_INLINE_VISIBILITY
209    native_handle_type native_handle() {return &__m_;}
210};
211
212class _LIBCPP_TYPE_VIS timed_mutex
213{
214    mutex              __m_;
215    condition_variable __cv_;
216    bool               __locked_;
217public:
218     timed_mutex();
219     ~timed_mutex();
220
221private:
222    timed_mutex(const timed_mutex&); // = delete;
223    timed_mutex& operator=(const timed_mutex&); // = delete;
224
225public:
226    void lock();
227    bool try_lock() _NOEXCEPT;
228    template <class _Rep, class _Period>
229        _LIBCPP_INLINE_VISIBILITY
230        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
231            {return try_lock_until(chrono::steady_clock::now() + __d);}
232    template <class _Clock, class _Duration>
233        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
234    void unlock() _NOEXCEPT;
235};
236
237template <class _Clock, class _Duration>
238bool
239timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
240{
241    using namespace chrono;
242    unique_lock<mutex> __lk(__m_);
243    bool no_timeout = _Clock::now() < __t;
244    while (no_timeout && __locked_)
245        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
246    if (!__locked_)
247    {
248        __locked_ = true;
249        return true;
250    }
251    return false;
252}
253
254class _LIBCPP_TYPE_VIS recursive_timed_mutex
255{
256    mutex              __m_;
257    condition_variable __cv_;
258    size_t             __count_;
259    pthread_t          __id_;
260public:
261     recursive_timed_mutex();
262     ~recursive_timed_mutex();
263
264private:
265    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
266    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
267
268public:
269    void lock();
270    bool try_lock() _NOEXCEPT;
271    template <class _Rep, class _Period>
272        _LIBCPP_INLINE_VISIBILITY
273        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
274            {return try_lock_until(chrono::steady_clock::now() + __d);}
275    template <class _Clock, class _Duration>
276        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
277    void unlock() _NOEXCEPT;
278};
279
280template <class _Clock, class _Duration>
281bool
282recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
283{
284    using namespace chrono;
285    pthread_t __id = pthread_self();
286    unique_lock<mutex> lk(__m_);
287    if (pthread_equal(__id, __id_))
288    {
289        if (__count_ == numeric_limits<size_t>::max())
290            return false;
291        ++__count_;
292        return true;
293    }
294    bool no_timeout = _Clock::now() < __t;
295    while (no_timeout && __count_ != 0)
296        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
297    if (__count_ == 0)
298    {
299        __count_ = 1;
300        __id_ = __id;
301        return true;
302    }
303    return false;
304}
305
306template <class _L0, class _L1>
307int
308try_lock(_L0& __l0, _L1& __l1)
309{
310    unique_lock<_L0> __u0(__l0, try_to_lock);
311    if (__u0.owns_lock())
312    {
313        if (__l1.try_lock())
314        {
315            __u0.release();
316            return -1;
317        }
318        else
319            return 1;
320    }
321    return 0;
322}
323
324#ifndef _LIBCPP_HAS_NO_VARIADICS
325
326template <class _L0, class _L1, class _L2, class... _L3>
327int
328try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
329{
330    int __r = 0;
331    unique_lock<_L0> __u0(__l0, try_to_lock);
332    if (__u0.owns_lock())
333    {
334        __r = try_lock(__l1, __l2, __l3...);
335        if (__r == -1)
336            __u0.release();
337        else
338            ++__r;
339    }
340    return __r;
341}
342
343#endif  // _LIBCPP_HAS_NO_VARIADICS
344
345template <class _L0, class _L1>
346void
347lock(_L0& __l0, _L1& __l1)
348{
349    while (true)
350    {
351        {
352            unique_lock<_L0> __u0(__l0);
353            if (__l1.try_lock())
354            {
355                __u0.release();
356                break;
357            }
358        }
359        sched_yield();
360        {
361            unique_lock<_L1> __u1(__l1);
362            if (__l0.try_lock())
363            {
364                __u1.release();
365                break;
366            }
367        }
368        sched_yield();
369    }
370}
371
372#ifndef _LIBCPP_HAS_NO_VARIADICS
373
374template <class _L0, class _L1, class _L2, class ..._L3>
375void
376__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
377{
378    while (true)
379    {
380        switch (__i)
381        {
382        case 0:
383            {
384                unique_lock<_L0> __u0(__l0);
385                __i = try_lock(__l1, __l2, __l3...);
386                if (__i == -1)
387                {
388                    __u0.release();
389                    return;
390                }
391            }
392            ++__i;
393            sched_yield();
394            break;
395        case 1:
396            {
397                unique_lock<_L1> __u1(__l1);
398                __i = try_lock(__l2, __l3..., __l0);
399                if (__i == -1)
400                {
401                    __u1.release();
402                    return;
403                }
404            }
405            if (__i == sizeof...(_L3) + 1)
406                __i = 0;
407            else
408                __i += 2;
409            sched_yield();
410            break;
411        default:
412            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
413            return;
414        }
415    }
416}
417
418template <class _L0, class _L1, class _L2, class ..._L3>
419inline _LIBCPP_INLINE_VISIBILITY
420void
421lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
422{
423    __lock_first(0, __l0, __l1, __l2, __l3...);
424}
425
426#endif  // _LIBCPP_HAS_NO_VARIADICS
427
428struct _LIBCPP_TYPE_VIS once_flag;
429
430#ifndef _LIBCPP_HAS_NO_VARIADICS
431
432template<class _Callable, class... _Args>
433_LIBCPP_INLINE_VISIBILITY
434void call_once(once_flag&, _Callable&&, _Args&&...);
435
436#else  // _LIBCPP_HAS_NO_VARIADICS
437
438template<class _Callable>
439_LIBCPP_INLINE_VISIBILITY
440void call_once(once_flag&, _Callable);
441
442#endif  // _LIBCPP_HAS_NO_VARIADICS
443
444struct _LIBCPP_TYPE_VIS_ONLY once_flag
445{
446    _LIBCPP_INLINE_VISIBILITY
447    _LIBCPP_CONSTEXPR
448        once_flag() _NOEXCEPT : __state_(0) {}
449
450private:
451    once_flag(const once_flag&); // = delete;
452    once_flag& operator=(const once_flag&); // = delete;
453
454    unsigned long __state_;
455
456#ifndef _LIBCPP_HAS_NO_VARIADICS
457    template<class _Callable, class... _Args>
458    friend
459    void call_once(once_flag&, _Callable&&, _Args&&...);
460#else  // _LIBCPP_HAS_NO_VARIADICS
461    template<class _Callable>
462    friend
463    void call_once(once_flag&, _Callable);
464#endif  // _LIBCPP_HAS_NO_VARIADICS
465};
466
467#ifndef _LIBCPP_HAS_NO_VARIADICS
468
469template <class _Fp>
470class __call_once_param
471{
472    _Fp __f_;
473public:
474#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
475    _LIBCPP_INLINE_VISIBILITY
476    explicit __call_once_param(_Fp&& __f) : __f_(_VSTD::move(__f)) {}
477#else
478    _LIBCPP_INLINE_VISIBILITY
479    explicit __call_once_param(const _Fp& __f) : __f_(__f) {}
480#endif
481
482    _LIBCPP_INLINE_VISIBILITY
483    void operator()()
484    {
485        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
486        __execute(_Index());
487    }
488
489private:
490    template <size_t ..._Indices>
491    _LIBCPP_INLINE_VISIBILITY
492    void __execute(__tuple_indices<_Indices...>)
493    {
494        __invoke(_VSTD::move(_VSTD::get<0>(__f_)), _VSTD::move(_VSTD::get<_Indices>(__f_))...);
495    }
496};
497
498#else
499
500template <class _Fp>
501class __call_once_param
502{
503    _Fp __f_;
504public:
505#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
506    _LIBCPP_INLINE_VISIBILITY
507    explicit __call_once_param(_Fp&& __f) : __f_(_VSTD::move(__f)) {}
508#else
509    _LIBCPP_INLINE_VISIBILITY
510    explicit __call_once_param(const _Fp& __f) : __f_(__f) {}
511#endif
512
513    _LIBCPP_INLINE_VISIBILITY
514    void operator()()
515    {
516        __f_();
517    }
518};
519
520#endif
521
522template <class _Fp>
523void
524__call_once_proxy(void* __vp)
525{
526    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
527    (*__p)();
528}
529
530_LIBCPP_FUNC_VIS void __call_once(volatile unsigned long&, void*, void(*)(void*));
531
532#ifndef _LIBCPP_HAS_NO_VARIADICS
533
534template<class _Callable, class... _Args>
535inline _LIBCPP_INLINE_VISIBILITY
536void
537call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
538{
539    if (__flag.__state_ != ~0ul)
540    {
541        typedef tuple<typename decay<_Callable>::type, typename decay<_Args>::type...> _Gp;
542        __call_once_param<_Gp> __p(_Gp(__decay_copy(_VSTD::forward<_Callable>(__func)),
543                                __decay_copy(_VSTD::forward<_Args>(__args))...));
544        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
545    }
546}
547
548#else  // _LIBCPP_HAS_NO_VARIADICS
549
550template<class _Callable>
551inline _LIBCPP_INLINE_VISIBILITY
552void
553call_once(once_flag& __flag, _Callable __func)
554{
555    if (__flag.__state_ != ~0ul)
556    {
557        __call_once_param<_Callable> __p(__func);
558        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
559    }
560}
561
562#endif  // _LIBCPP_HAS_NO_VARIADICS
563
564_LIBCPP_END_NAMESPACE_STD
565
566#endif  // _LIBCPP_MUTEX
567