1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___MUTEX_BASE
11#define _LIBCPP___MUTEX_BASE
12
13#include <__config>
14#include <chrono>
15#include <system_error>
16#include <__threading_support>
17
18
19#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20#pragma GCC system_header
21#endif
22
23_LIBCPP_PUSH_MACROS
24#include <__undef_macros>
25
26
27_LIBCPP_BEGIN_NAMESPACE_STD
28
29#ifndef _LIBCPP_HAS_NO_THREADS
30
31#ifndef _LIBCPP_THREAD_SAFETY_ANNOTATION
32#  ifdef _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
33#    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x) __attribute__((x))
34#  else
35#    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x)
36#  endif
37#endif  // _LIBCPP_THREAD_SAFETY_ANNOTATION
38
39
40class _LIBCPP_TYPE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(capability("mutex")) mutex
41{
42    __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER;
43
44public:
45    _LIBCPP_INLINE_VISIBILITY
46    _LIBCPP_CONSTEXPR mutex() = default;
47
48    mutex(const mutex&) = delete;
49    mutex& operator=(const mutex&) = delete;
50
51#if defined(_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION)
52    ~mutex() = default;
53#else
54    ~mutex() _NOEXCEPT;
55#endif
56
57    void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability());
58    bool try_lock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_capability(true));
59    void unlock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability());
60
61    typedef __libcpp_mutex_t* native_handle_type;
62    _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__m_;}
63};
64
65static_assert(is_nothrow_default_constructible<mutex>::value,
66              "the default constructor for std::mutex must be nothrow");
67
68struct _LIBCPP_TYPE_VIS defer_lock_t {};
69struct _LIBCPP_TYPE_VIS try_to_lock_t {};
70struct _LIBCPP_TYPE_VIS adopt_lock_t {};
71
72#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
73
74extern _LIBCPP_EXPORTED_FROM_ABI const defer_lock_t  defer_lock;
75extern _LIBCPP_EXPORTED_FROM_ABI const try_to_lock_t try_to_lock;
76extern _LIBCPP_EXPORTED_FROM_ABI const adopt_lock_t  adopt_lock;
77
78#else
79
80/* _LIBCPP_INLINE_VAR */ constexpr defer_lock_t  defer_lock  = defer_lock_t();
81/* _LIBCPP_INLINE_VAR */ constexpr try_to_lock_t try_to_lock = try_to_lock_t();
82/* _LIBCPP_INLINE_VAR */ constexpr adopt_lock_t  adopt_lock  = adopt_lock_t();
83
84#endif
85
86template <class _Mutex>
87class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable)
88lock_guard
89{
90public:
91    typedef _Mutex mutex_type;
92
93private:
94    mutex_type& __m_;
95public:
96
97    _LIBCPP_INLINE_VISIBILITY
98    explicit lock_guard(mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
99        : __m_(__m) {__m_.lock();}
100    _LIBCPP_INLINE_VISIBILITY
101    lock_guard(mutex_type& __m, adopt_lock_t) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
102        : __m_(__m) {}
103    _LIBCPP_INLINE_VISIBILITY
104    ~lock_guard() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
105
106private:
107    lock_guard(lock_guard const&) _LIBCPP_EQUAL_DELETE;
108    lock_guard& operator=(lock_guard const&) _LIBCPP_EQUAL_DELETE;
109};
110_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(lock_guard);
111
112
113template <class _Mutex>
114class _LIBCPP_TEMPLATE_VIS unique_lock
115{
116public:
117    typedef _Mutex mutex_type;
118
119private:
120    mutex_type* __m_;
121    bool __owns_;
122
123public:
124    _LIBCPP_INLINE_VISIBILITY
125    unique_lock() _NOEXCEPT : __m_(nullptr), __owns_(false) {}
126    _LIBCPP_INLINE_VISIBILITY
127    explicit unique_lock(mutex_type& __m)
128        : __m_(_VSTD::addressof(__m)), __owns_(true) {__m_->lock();}
129    _LIBCPP_INLINE_VISIBILITY
130    unique_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
131        : __m_(_VSTD::addressof(__m)), __owns_(false) {}
132    _LIBCPP_INLINE_VISIBILITY
133    unique_lock(mutex_type& __m, try_to_lock_t)
134        : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock()) {}
135    _LIBCPP_INLINE_VISIBILITY
136    unique_lock(mutex_type& __m, adopt_lock_t)
137        : __m_(_VSTD::addressof(__m)), __owns_(true) {}
138    template <class _Clock, class _Duration>
139    _LIBCPP_INLINE_VISIBILITY
140        unique_lock(mutex_type& __m, const chrono::time_point<_Clock, _Duration>& __t)
141            : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_until(__t)) {}
142    template <class _Rep, class _Period>
143    _LIBCPP_INLINE_VISIBILITY
144        unique_lock(mutex_type& __m, const chrono::duration<_Rep, _Period>& __d)
145            : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_for(__d)) {}
146    _LIBCPP_INLINE_VISIBILITY
147    ~unique_lock()
148    {
149        if (__owns_)
150            __m_->unlock();
151    }
152
153private:
154    unique_lock(unique_lock const&); // = delete;
155    unique_lock& operator=(unique_lock const&); // = delete;
156
157public:
158#ifndef _LIBCPP_CXX03_LANG
159    _LIBCPP_INLINE_VISIBILITY
160    unique_lock(unique_lock&& __u) _NOEXCEPT
161        : __m_(__u.__m_), __owns_(__u.__owns_)
162        {__u.__m_ = nullptr; __u.__owns_ = false;}
163    _LIBCPP_INLINE_VISIBILITY
164    unique_lock& operator=(unique_lock&& __u) _NOEXCEPT
165        {
166            if (__owns_)
167                __m_->unlock();
168            __m_ = __u.__m_;
169            __owns_ = __u.__owns_;
170            __u.__m_ = nullptr;
171            __u.__owns_ = false;
172            return *this;
173        }
174
175#endif  // _LIBCPP_CXX03_LANG
176
177    void lock();
178    bool try_lock();
179
180    template <class _Rep, class _Period>
181        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d);
182    template <class _Clock, class _Duration>
183        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
184
185    void unlock();
186
187    _LIBCPP_INLINE_VISIBILITY
188    void swap(unique_lock& __u) _NOEXCEPT
189    {
190        _VSTD::swap(__m_, __u.__m_);
191        _VSTD::swap(__owns_, __u.__owns_);
192    }
193    _LIBCPP_INLINE_VISIBILITY
194    mutex_type* release() _NOEXCEPT
195    {
196        mutex_type* __m = __m_;
197        __m_ = nullptr;
198        __owns_ = false;
199        return __m;
200    }
201
202    _LIBCPP_INLINE_VISIBILITY
203    bool owns_lock() const _NOEXCEPT {return __owns_;}
204    _LIBCPP_INLINE_VISIBILITY
205    _LIBCPP_EXPLICIT
206        operator bool () const _NOEXCEPT {return __owns_;}
207    _LIBCPP_INLINE_VISIBILITY
208    mutex_type* mutex() const _NOEXCEPT {return __m_;}
209};
210_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(unique_lock);
211
212template <class _Mutex>
213void
214unique_lock<_Mutex>::lock()
215{
216    if (__m_ == nullptr)
217        __throw_system_error(EPERM, "unique_lock::lock: references null mutex");
218    if (__owns_)
219        __throw_system_error(EDEADLK, "unique_lock::lock: already locked");
220    __m_->lock();
221    __owns_ = true;
222}
223
224template <class _Mutex>
225bool
226unique_lock<_Mutex>::try_lock()
227{
228    if (__m_ == nullptr)
229        __throw_system_error(EPERM, "unique_lock::try_lock: references null mutex");
230    if (__owns_)
231        __throw_system_error(EDEADLK, "unique_lock::try_lock: already locked");
232    __owns_ = __m_->try_lock();
233    return __owns_;
234}
235
236template <class _Mutex>
237template <class _Rep, class _Period>
238bool
239unique_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d)
240{
241    if (__m_ == nullptr)
242        __throw_system_error(EPERM, "unique_lock::try_lock_for: references null mutex");
243    if (__owns_)
244        __throw_system_error(EDEADLK, "unique_lock::try_lock_for: already locked");
245    __owns_ = __m_->try_lock_for(__d);
246    return __owns_;
247}
248
249template <class _Mutex>
250template <class _Clock, class _Duration>
251bool
252unique_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
253{
254    if (__m_ == nullptr)
255        __throw_system_error(EPERM, "unique_lock::try_lock_until: references null mutex");
256    if (__owns_)
257        __throw_system_error(EDEADLK, "unique_lock::try_lock_until: already locked");
258    __owns_ = __m_->try_lock_until(__t);
259    return __owns_;
260}
261
262template <class _Mutex>
263void
264unique_lock<_Mutex>::unlock()
265{
266    if (!__owns_)
267        __throw_system_error(EPERM, "unique_lock::unlock: not locked");
268    __m_->unlock();
269    __owns_ = false;
270}
271
272template <class _Mutex>
273inline _LIBCPP_INLINE_VISIBILITY
274void
275swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) _NOEXCEPT
276    {__x.swap(__y);}
277
278//enum class cv_status
279_LIBCPP_DECLARE_STRONG_ENUM(cv_status)
280{
281    no_timeout,
282    timeout
283};
284_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)
285
286class _LIBCPP_TYPE_VIS condition_variable
287{
288    __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
289public:
290    _LIBCPP_INLINE_VISIBILITY
291    _LIBCPP_CONSTEXPR condition_variable() _NOEXCEPT = default;
292
293#ifdef _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
294    ~condition_variable() = default;
295#else
296    ~condition_variable();
297#endif
298
299    condition_variable(const condition_variable&) = delete;
300    condition_variable& operator=(const condition_variable&) = delete;
301
302    void notify_one() _NOEXCEPT;
303    void notify_all() _NOEXCEPT;
304
305    void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
306    template <class _Predicate>
307        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
308        void wait(unique_lock<mutex>& __lk, _Predicate __pred);
309
310    template <class _Clock, class _Duration>
311        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
312        cv_status
313        wait_until(unique_lock<mutex>& __lk,
314                   const chrono::time_point<_Clock, _Duration>& __t);
315
316    template <class _Clock, class _Duration, class _Predicate>
317        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
318        bool
319        wait_until(unique_lock<mutex>& __lk,
320                   const chrono::time_point<_Clock, _Duration>& __t,
321                   _Predicate __pred);
322
323    template <class _Rep, class _Period>
324        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
325        cv_status
326        wait_for(unique_lock<mutex>& __lk,
327                 const chrono::duration<_Rep, _Period>& __d);
328
329    template <class _Rep, class _Period, class _Predicate>
330        bool
331        _LIBCPP_INLINE_VISIBILITY
332        wait_for(unique_lock<mutex>& __lk,
333                 const chrono::duration<_Rep, _Period>& __d,
334                 _Predicate __pred);
335
336    typedef __libcpp_condvar_t* native_handle_type;
337    _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__cv_;}
338
339private:
340    void __do_timed_wait(unique_lock<mutex>& __lk,
341       chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;
342};
343#endif // !_LIBCPP_HAS_NO_THREADS
344
345template <class _To, class _Rep, class _Period>
346inline _LIBCPP_INLINE_VISIBILITY
347typename enable_if
348<
349    chrono::__is_duration<_To>::value,
350    _To
351>::type
352__ceil(chrono::duration<_Rep, _Period> __d)
353{
354    using namespace chrono;
355    _To __r = duration_cast<_To>(__d);
356    if (__r < __d)
357        ++__r;
358    return __r;
359}
360
361#ifndef _LIBCPP_HAS_NO_THREADS
362template <class _Predicate>
363void
364condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred)
365{
366    while (!__pred())
367        wait(__lk);
368}
369
370template <class _Clock, class _Duration>
371cv_status
372condition_variable::wait_until(unique_lock<mutex>& __lk,
373                               const chrono::time_point<_Clock, _Duration>& __t)
374{
375    using namespace chrono;
376    wait_for(__lk, __t - _Clock::now());
377    return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout;
378}
379
380template <class _Clock, class _Duration, class _Predicate>
381bool
382condition_variable::wait_until(unique_lock<mutex>& __lk,
383                   const chrono::time_point<_Clock, _Duration>& __t,
384                   _Predicate __pred)
385{
386    while (!__pred())
387    {
388        if (wait_until(__lk, __t) == cv_status::timeout)
389            return __pred();
390    }
391    return true;
392}
393
394template <class _Rep, class _Period>
395cv_status
396condition_variable::wait_for(unique_lock<mutex>& __lk,
397                             const chrono::duration<_Rep, _Period>& __d)
398{
399    using namespace chrono;
400    if (__d <= __d.zero())
401        return cv_status::timeout;
402    typedef time_point<system_clock, duration<long double, nano> > __sys_tpf;
403    typedef time_point<system_clock, nanoseconds> __sys_tpi;
404    __sys_tpf _Max = __sys_tpi::max();
405    steady_clock::time_point __c_now = steady_clock::now();
406    system_clock::time_point __s_now = system_clock::now();
407    if (_Max - __d > __s_now)
408        __do_timed_wait(__lk, __s_now + __ceil<nanoseconds>(__d));
409    else
410        __do_timed_wait(__lk, __sys_tpi::max());
411    return steady_clock::now() - __c_now < __d ? cv_status::no_timeout :
412                                                 cv_status::timeout;
413}
414
415template <class _Rep, class _Period, class _Predicate>
416inline
417bool
418condition_variable::wait_for(unique_lock<mutex>& __lk,
419                             const chrono::duration<_Rep, _Period>& __d,
420                             _Predicate __pred)
421{
422    return wait_until(__lk, chrono::steady_clock::now() + __d,
423                      _VSTD::move(__pred));
424}
425
426#endif // !_LIBCPP_HAS_NO_THREADS
427
428_LIBCPP_END_NAMESPACE_STD
429
430_LIBCPP_POP_MACROS
431
432#endif  // _LIBCPP___MUTEX_BASE
433