mutex revision 232924 
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#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_VISIBLE 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();
205    void unlock();
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_VISIBLE 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();
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();
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_VISIBLE 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();
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();
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 once_flag;
429
430#ifndef _LIBCPP_HAS_NO_VARIADICS
431
432template<class _Callable, class... _Args>
433  void call_once(once_flag&, _Callable&&, _Args&&...);
434
435#else  // _LIBCPP_HAS_NO_VARIADICS
436
437template<class _Callable>
438  void call_once(once_flag&, _Callable);
439
440#endif  // _LIBCPP_HAS_NO_VARIADICS
441
442struct _LIBCPP_VISIBLE once_flag
443{
444    _LIBCPP_INLINE_VISIBILITY
445    // constexpr
446        once_flag() {}
447
448private:
449    once_flag(const once_flag&); // = delete;
450    once_flag& operator=(const once_flag&); // = delete;
451
452    unsigned long __state_;
453
454#ifndef _LIBCPP_HAS_NO_VARIADICS
455    template<class _Callable, class... _Args>
456    friend
457    void call_once(once_flag&, _Callable&&, _Args&&...);
458#else  // _LIBCPP_HAS_NO_VARIADICS
459    template<class _Callable>
460    friend
461    void call_once(once_flag&, _Callable);
462#endif  // _LIBCPP_HAS_NO_VARIADICS
463};
464
465#ifndef _LIBCPP_HAS_NO_VARIADICS
466
467template <class _Fp>
468class __call_once_param
469{
470    _Fp __f_;
471public:
472#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
473    _LIBCPP_INLINE_VISIBILITY
474    explicit __call_once_param(_Fp&& __f) : __f_(_VSTD::move(__f)) {}
475#else
476    _LIBCPP_INLINE_VISIBILITY
477    explicit __call_once_param(const _Fp& __f) : __f_(__f) {}
478#endif
479
480    _LIBCPP_INLINE_VISIBILITY
481    void operator()()
482    {
483        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
484        __execute(_Index());
485    }
486
487private:
488    template <size_t ..._Indices>
489    _LIBCPP_INLINE_VISIBILITY
490    void __execute(__tuple_indices<_Indices...>)
491    {
492        __invoke(_VSTD::move(_VSTD::get<0>(__f_)), _VSTD::move(_VSTD::get<_Indices>(__f_))...);
493    }
494};
495
496#else
497
498template <class _Fp>
499class __call_once_param
500{
501    _Fp __f_;
502public:
503#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
504    _LIBCPP_INLINE_VISIBILITY
505    explicit __call_once_param(_Fp&& __f) : __f_(_VSTD::move(__f)) {}
506#else
507    _LIBCPP_INLINE_VISIBILITY
508    explicit __call_once_param(const _Fp& __f) : __f_(__f) {}
509#endif
510
511    _LIBCPP_INLINE_VISIBILITY
512    void operator()()
513    {
514        __f_();
515    }
516};
517
518#endif
519
520template <class _Fp>
521void
522__call_once_proxy(void* __vp)
523{
524    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
525    (*__p)();
526}
527
528void __call_once(volatile unsigned long&, void*, void(*)(void*));
529
530#ifndef _LIBCPP_HAS_NO_VARIADICS
531
532template<class _Callable, class... _Args>
533inline _LIBCPP_INLINE_VISIBILITY
534void
535call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
536{
537    if (__flag.__state_ != ~0ul)
538    {
539        typedef tuple<typename decay<_Callable>::type, typename decay<_Args>::type...> _Gp;
540        __call_once_param<_Gp> __p(_Gp(__decay_copy(_VSTD::forward<_Callable>(__func)),
541                                __decay_copy(_VSTD::forward<_Args>(__args))...));
542        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
543    }
544}
545
546#else  // _LIBCPP_HAS_NO_VARIADICS
547
548template<class _Callable>
549inline _LIBCPP_INLINE_VISIBILITY
550void
551call_once(once_flag& __flag, _Callable __func)
552{
553    if (__flag.__state_ != ~0ul)
554    {
555        __call_once_param<_Callable> __p(__func);
556        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
557    }
558}
559
560#endif  // _LIBCPP_HAS_NO_VARIADICS
561
562_LIBCPP_END_NAMESPACE_STD
563
564#endif  // _LIBCPP_MUTEX
565