mutex revision 288943 
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#include <memory>
179#ifndef _LIBCPP_HAS_NO_VARIADICS
180#include <tuple>
181#endif
182#include <sched.h>
183
184#include <__undef_min_max>
185
186#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
187#pragma GCC system_header
188#endif
189
190_LIBCPP_BEGIN_NAMESPACE_STD
191
192#ifndef _LIBCPP_HAS_NO_THREADS
193
194class _LIBCPP_TYPE_VIS recursive_mutex
195{
196    pthread_mutex_t __m_;
197
198public:
199     recursive_mutex();
200     ~recursive_mutex();
201
202private:
203    recursive_mutex(const recursive_mutex&); // = delete;
204    recursive_mutex& operator=(const recursive_mutex&); // = delete;
205
206public:
207    void lock();
208    bool try_lock() _NOEXCEPT;
209    void unlock()  _NOEXCEPT;
210
211    typedef pthread_mutex_t* native_handle_type;
212    _LIBCPP_INLINE_VISIBILITY
213    native_handle_type native_handle() {return &__m_;}
214};
215
216class _LIBCPP_TYPE_VIS timed_mutex
217{
218    mutex              __m_;
219    condition_variable __cv_;
220    bool               __locked_;
221public:
222     timed_mutex();
223     ~timed_mutex();
224
225private:
226    timed_mutex(const timed_mutex&); // = delete;
227    timed_mutex& operator=(const timed_mutex&); // = delete;
228
229public:
230    void lock();
231    bool try_lock() _NOEXCEPT;
232    template <class _Rep, class _Period>
233        _LIBCPP_INLINE_VISIBILITY
234        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
235            {return try_lock_until(chrono::steady_clock::now() + __d);}
236    template <class _Clock, class _Duration>
237        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
238    void unlock() _NOEXCEPT;
239};
240
241template <class _Clock, class _Duration>
242bool
243timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
244{
245    using namespace chrono;
246    unique_lock<mutex> __lk(__m_);
247    bool no_timeout = _Clock::now() < __t;
248    while (no_timeout && __locked_)
249        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
250    if (!__locked_)
251    {
252        __locked_ = true;
253        return true;
254    }
255    return false;
256}
257
258class _LIBCPP_TYPE_VIS recursive_timed_mutex
259{
260    mutex              __m_;
261    condition_variable __cv_;
262    size_t             __count_;
263    pthread_t          __id_;
264public:
265     recursive_timed_mutex();
266     ~recursive_timed_mutex();
267
268private:
269    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
270    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
271
272public:
273    void lock();
274    bool try_lock() _NOEXCEPT;
275    template <class _Rep, class _Period>
276        _LIBCPP_INLINE_VISIBILITY
277        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
278            {return try_lock_until(chrono::steady_clock::now() + __d);}
279    template <class _Clock, class _Duration>
280        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
281    void unlock() _NOEXCEPT;
282};
283
284template <class _Clock, class _Duration>
285bool
286recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
287{
288    using namespace chrono;
289    pthread_t __id = pthread_self();
290    unique_lock<mutex> lk(__m_);
291    if (pthread_equal(__id, __id_))
292    {
293        if (__count_ == numeric_limits<size_t>::max())
294            return false;
295        ++__count_;
296        return true;
297    }
298    bool no_timeout = _Clock::now() < __t;
299    while (no_timeout && __count_ != 0)
300        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
301    if (__count_ == 0)
302    {
303        __count_ = 1;
304        __id_ = __id;
305        return true;
306    }
307    return false;
308}
309
310template <class _L0, class _L1>
311int
312try_lock(_L0& __l0, _L1& __l1)
313{
314    unique_lock<_L0> __u0(__l0, try_to_lock);
315    if (__u0.owns_lock())
316    {
317        if (__l1.try_lock())
318        {
319            __u0.release();
320            return -1;
321        }
322        else
323            return 1;
324    }
325    return 0;
326}
327
328#ifndef _LIBCPP_HAS_NO_VARIADICS
329
330template <class _L0, class _L1, class _L2, class... _L3>
331int
332try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
333{
334    int __r = 0;
335    unique_lock<_L0> __u0(__l0, try_to_lock);
336    if (__u0.owns_lock())
337    {
338        __r = try_lock(__l1, __l2, __l3...);
339        if (__r == -1)
340            __u0.release();
341        else
342            ++__r;
343    }
344    return __r;
345}
346
347#endif  // _LIBCPP_HAS_NO_VARIADICS
348
349template <class _L0, class _L1>
350void
351lock(_L0& __l0, _L1& __l1)
352{
353    while (true)
354    {
355        {
356            unique_lock<_L0> __u0(__l0);
357            if (__l1.try_lock())
358            {
359                __u0.release();
360                break;
361            }
362        }
363        sched_yield();
364        {
365            unique_lock<_L1> __u1(__l1);
366            if (__l0.try_lock())
367            {
368                __u1.release();
369                break;
370            }
371        }
372        sched_yield();
373    }
374}
375
376#ifndef _LIBCPP_HAS_NO_VARIADICS
377
378template <class _L0, class _L1, class _L2, class ..._L3>
379void
380__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
381{
382    while (true)
383    {
384        switch (__i)
385        {
386        case 0:
387            {
388                unique_lock<_L0> __u0(__l0);
389                __i = try_lock(__l1, __l2, __l3...);
390                if (__i == -1)
391                {
392                    __u0.release();
393                    return;
394                }
395            }
396            ++__i;
397            sched_yield();
398            break;
399        case 1:
400            {
401                unique_lock<_L1> __u1(__l1);
402                __i = try_lock(__l2, __l3..., __l0);
403                if (__i == -1)
404                {
405                    __u1.release();
406                    return;
407                }
408            }
409            if (__i == sizeof...(_L3) + 1)
410                __i = 0;
411            else
412                __i += 2;
413            sched_yield();
414            break;
415        default:
416            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
417            return;
418        }
419    }
420}
421
422template <class _L0, class _L1, class _L2, class ..._L3>
423inline _LIBCPP_INLINE_VISIBILITY
424void
425lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
426{
427    __lock_first(0, __l0, __l1, __l2, __l3...);
428}
429
430#endif  // _LIBCPP_HAS_NO_VARIADICS
431
432#endif // !_LIBCPP_HAS_NO_THREADS
433
434struct _LIBCPP_TYPE_VIS_ONLY once_flag;
435
436#ifndef _LIBCPP_HAS_NO_VARIADICS
437
438template<class _Callable, class... _Args>
439_LIBCPP_INLINE_VISIBILITY
440void call_once(once_flag&, _Callable&&, _Args&&...);
441
442#else  // _LIBCPP_HAS_NO_VARIADICS
443
444template<class _Callable>
445_LIBCPP_INLINE_VISIBILITY
446void call_once(once_flag&, _Callable&);
447
448template<class _Callable>
449_LIBCPP_INLINE_VISIBILITY
450void call_once(once_flag&, const _Callable&);
451
452#endif  // _LIBCPP_HAS_NO_VARIADICS
453
454struct _LIBCPP_TYPE_VIS_ONLY once_flag
455{
456    _LIBCPP_INLINE_VISIBILITY
457    _LIBCPP_CONSTEXPR
458        once_flag() _NOEXCEPT : __state_(0) {}
459
460private:
461    once_flag(const once_flag&); // = delete;
462    once_flag& operator=(const once_flag&); // = delete;
463
464    unsigned long __state_;
465
466#ifndef _LIBCPP_HAS_NO_VARIADICS
467    template<class _Callable, class... _Args>
468    friend
469    void call_once(once_flag&, _Callable&&, _Args&&...);
470#else  // _LIBCPP_HAS_NO_VARIADICS
471    template<class _Callable>
472    friend
473    void call_once(once_flag&, _Callable&);
474
475    template<class _Callable>
476    friend
477    void call_once(once_flag&, const _Callable&);
478#endif  // _LIBCPP_HAS_NO_VARIADICS
479};
480
481#ifndef _LIBCPP_HAS_NO_VARIADICS
482
483template <class _Fp>
484class __call_once_param
485{
486    _Fp& __f_;
487public:
488    _LIBCPP_INLINE_VISIBILITY
489    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
490
491    _LIBCPP_INLINE_VISIBILITY
492    void operator()()
493    {
494        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
495        __execute(_Index());
496    }
497
498private:
499    template <size_t ..._Indices>
500    _LIBCPP_INLINE_VISIBILITY
501    void __execute(__tuple_indices<_Indices...>)
502    {
503        __invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
504    }
505};
506
507#else
508
509template <class _Fp>
510class __call_once_param
511{
512    _Fp& __f_;
513public:
514    _LIBCPP_INLINE_VISIBILITY
515    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
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 (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
544    {
545        typedef tuple<_Callable&&, _Args&&...> _Gp;
546        _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
547        __call_once_param<_Gp> __p(__f);
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 (__libcpp_relaxed_load(&__flag.__state_) != ~0ul)
560    {
561        __call_once_param<_Callable> __p(__func);
562        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
563    }
564}
565
566template<class _Callable>
567inline _LIBCPP_INLINE_VISIBILITY
568void
569call_once(once_flag& __flag, const _Callable& __func)
570{
571    if (__flag.__state_ != ~0ul)
572    {
573        __call_once_param<const _Callable> __p(__func);
574        __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
575    }
576}
577
578#endif  // _LIBCPP_HAS_NO_VARIADICS
579
580_LIBCPP_END_NAMESPACE_STD
581
582#endif  // _LIBCPP_MUTEX
583