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
111template <class _Mutex>
112class _LIBCPP_TEMPLATE_VIS unique_lock
113{
114public:
115    typedef _Mutex mutex_type;
116
117private:
118    mutex_type* __m_;
119    bool __owns_;
120
121public:
122    _LIBCPP_INLINE_VISIBILITY
123    unique_lock() _NOEXCEPT : __m_(nullptr), __owns_(false) {}
124    _LIBCPP_INLINE_VISIBILITY
125    explicit unique_lock(mutex_type& __m)
126        : __m_(_VSTD::addressof(__m)), __owns_(true) {__m_->lock();}
127    _LIBCPP_INLINE_VISIBILITY
128    unique_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
129        : __m_(_VSTD::addressof(__m)), __owns_(false) {}
130    _LIBCPP_INLINE_VISIBILITY
131    unique_lock(mutex_type& __m, try_to_lock_t)
132        : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock()) {}
133    _LIBCPP_INLINE_VISIBILITY
134    unique_lock(mutex_type& __m, adopt_lock_t)
135        : __m_(_VSTD::addressof(__m)), __owns_(true) {}
136    template <class _Clock, class _Duration>
137    _LIBCPP_INLINE_VISIBILITY
138        unique_lock(mutex_type& __m, const chrono::time_point<_Clock, _Duration>& __t)
139            : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_until(__t)) {}
140    template <class _Rep, class _Period>
141    _LIBCPP_INLINE_VISIBILITY
142        unique_lock(mutex_type& __m, const chrono::duration<_Rep, _Period>& __d)
143            : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_for(__d)) {}
144    _LIBCPP_INLINE_VISIBILITY
145    ~unique_lock()
146    {
147        if (__owns_)
148            __m_->unlock();
149    }
150
151private:
152    unique_lock(unique_lock const&); // = delete;
153    unique_lock& operator=(unique_lock const&); // = delete;
154
155public:
156#ifndef _LIBCPP_CXX03_LANG
157    _LIBCPP_INLINE_VISIBILITY
158    unique_lock(unique_lock&& __u) _NOEXCEPT
159        : __m_(__u.__m_), __owns_(__u.__owns_)
160        {__u.__m_ = nullptr; __u.__owns_ = false;}
161    _LIBCPP_INLINE_VISIBILITY
162    unique_lock& operator=(unique_lock&& __u) _NOEXCEPT
163        {
164            if (__owns_)
165                __m_->unlock();
166            __m_ = __u.__m_;
167            __owns_ = __u.__owns_;
168            __u.__m_ = nullptr;
169            __u.__owns_ = false;
170            return *this;
171        }
172
173#endif  // _LIBCPP_CXX03_LANG
174
175    void lock();
176    bool try_lock();
177
178    template <class _Rep, class _Period>
179        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d);
180    template <class _Clock, class _Duration>
181        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
182
183    void unlock();
184
185    _LIBCPP_INLINE_VISIBILITY
186    void swap(unique_lock& __u) _NOEXCEPT
187    {
188        _VSTD::swap(__m_, __u.__m_);
189        _VSTD::swap(__owns_, __u.__owns_);
190    }
191    _LIBCPP_INLINE_VISIBILITY
192    mutex_type* release() _NOEXCEPT
193    {
194        mutex_type* __m = __m_;
195        __m_ = nullptr;
196        __owns_ = false;
197        return __m;
198    }
199
200    _LIBCPP_INLINE_VISIBILITY
201    bool owns_lock() const _NOEXCEPT {return __owns_;}
202    _LIBCPP_INLINE_VISIBILITY
203    _LIBCPP_EXPLICIT
204        operator bool () const _NOEXCEPT {return __owns_;}
205    _LIBCPP_INLINE_VISIBILITY
206    mutex_type* mutex() const _NOEXCEPT {return __m_;}
207};
208
209template <class _Mutex>
210void
211unique_lock<_Mutex>::lock()
212{
213    if (__m_ == nullptr)
214        __throw_system_error(EPERM, "unique_lock::lock: references null mutex");
215    if (__owns_)
216        __throw_system_error(EDEADLK, "unique_lock::lock: already locked");
217    __m_->lock();
218    __owns_ = true;
219}
220
221template <class _Mutex>
222bool
223unique_lock<_Mutex>::try_lock()
224{
225    if (__m_ == nullptr)
226        __throw_system_error(EPERM, "unique_lock::try_lock: references null mutex");
227    if (__owns_)
228        __throw_system_error(EDEADLK, "unique_lock::try_lock: already locked");
229    __owns_ = __m_->try_lock();
230    return __owns_;
231}
232
233template <class _Mutex>
234template <class _Rep, class _Period>
235bool
236unique_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d)
237{
238    if (__m_ == nullptr)
239        __throw_system_error(EPERM, "unique_lock::try_lock_for: references null mutex");
240    if (__owns_)
241        __throw_system_error(EDEADLK, "unique_lock::try_lock_for: already locked");
242    __owns_ = __m_->try_lock_for(__d);
243    return __owns_;
244}
245
246template <class _Mutex>
247template <class _Clock, class _Duration>
248bool
249unique_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
250{
251    if (__m_ == nullptr)
252        __throw_system_error(EPERM, "unique_lock::try_lock_until: references null mutex");
253    if (__owns_)
254        __throw_system_error(EDEADLK, "unique_lock::try_lock_until: already locked");
255    __owns_ = __m_->try_lock_until(__t);
256    return __owns_;
257}
258
259template <class _Mutex>
260void
261unique_lock<_Mutex>::unlock()
262{
263    if (!__owns_)
264        __throw_system_error(EPERM, "unique_lock::unlock: not locked");
265    __m_->unlock();
266    __owns_ = false;
267}
268
269template <class _Mutex>
270inline _LIBCPP_INLINE_VISIBILITY
271void
272swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) _NOEXCEPT
273    {__x.swap(__y);}
274
275//enum class cv_status
276_LIBCPP_DECLARE_STRONG_ENUM(cv_status)
277{
278    no_timeout,
279    timeout
280};
281_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)
282
283class _LIBCPP_TYPE_VIS condition_variable
284{
285    __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
286public:
287    _LIBCPP_INLINE_VISIBILITY
288    _LIBCPP_CONSTEXPR condition_variable() _NOEXCEPT = default;
289
290#ifdef _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
291    ~condition_variable() = default;
292#else
293    ~condition_variable();
294#endif
295
296    condition_variable(const condition_variable&) = delete;
297    condition_variable& operator=(const condition_variable&) = delete;
298
299    void notify_one() _NOEXCEPT;
300    void notify_all() _NOEXCEPT;
301
302    void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
303    template <class _Predicate>
304        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
305        void wait(unique_lock<mutex>& __lk, _Predicate __pred);
306
307    template <class _Clock, class _Duration>
308        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
309        cv_status
310        wait_until(unique_lock<mutex>& __lk,
311                   const chrono::time_point<_Clock, _Duration>& __t);
312
313    template <class _Clock, class _Duration, class _Predicate>
314        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
315        bool
316        wait_until(unique_lock<mutex>& __lk,
317                   const chrono::time_point<_Clock, _Duration>& __t,
318                   _Predicate __pred);
319
320    template <class _Rep, class _Period>
321        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
322        cv_status
323        wait_for(unique_lock<mutex>& __lk,
324                 const chrono::duration<_Rep, _Period>& __d);
325
326    template <class _Rep, class _Period, class _Predicate>
327        bool
328        _LIBCPP_INLINE_VISIBILITY
329        wait_for(unique_lock<mutex>& __lk,
330                 const chrono::duration<_Rep, _Period>& __d,
331                 _Predicate __pred);
332
333    typedef __libcpp_condvar_t* native_handle_type;
334    _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__cv_;}
335
336private:
337    void __do_timed_wait(unique_lock<mutex>& __lk,
338       chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;
339};
340#endif // !_LIBCPP_HAS_NO_THREADS
341
342template <class _To, class _Rep, class _Period>
343inline _LIBCPP_INLINE_VISIBILITY
344typename enable_if
345<
346    chrono::__is_duration<_To>::value,
347    _To
348>::type
349__ceil(chrono::duration<_Rep, _Period> __d)
350{
351    using namespace chrono;
352    _To __r = duration_cast<_To>(__d);
353    if (__r < __d)
354        ++__r;
355    return __r;
356}
357
358#ifndef _LIBCPP_HAS_NO_THREADS
359template <class _Predicate>
360void
361condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred)
362{
363    while (!__pred())
364        wait(__lk);
365}
366
367template <class _Clock, class _Duration>
368cv_status
369condition_variable::wait_until(unique_lock<mutex>& __lk,
370                               const chrono::time_point<_Clock, _Duration>& __t)
371{
372    using namespace chrono;
373    wait_for(__lk, __t - _Clock::now());
374    return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout;
375}
376
377template <class _Clock, class _Duration, class _Predicate>
378bool
379condition_variable::wait_until(unique_lock<mutex>& __lk,
380                   const chrono::time_point<_Clock, _Duration>& __t,
381                   _Predicate __pred)
382{
383    while (!__pred())
384    {
385        if (wait_until(__lk, __t) == cv_status::timeout)
386            return __pred();
387    }
388    return true;
389}
390
391template <class _Rep, class _Period>
392cv_status
393condition_variable::wait_for(unique_lock<mutex>& __lk,
394                             const chrono::duration<_Rep, _Period>& __d)
395{
396    using namespace chrono;
397    if (__d <= __d.zero())
398        return cv_status::timeout;
399    typedef time_point<system_clock, duration<long double, nano> > __sys_tpf;
400    typedef time_point<system_clock, nanoseconds> __sys_tpi;
401    __sys_tpf _Max = __sys_tpi::max();
402    steady_clock::time_point __c_now = steady_clock::now();
403    system_clock::time_point __s_now = system_clock::now();
404    if (_Max - __d > __s_now)
405        __do_timed_wait(__lk, __s_now + __ceil<nanoseconds>(__d));
406    else
407        __do_timed_wait(__lk, __sys_tpi::max());
408    return steady_clock::now() - __c_now < __d ? cv_status::no_timeout :
409                                                 cv_status::timeout;
410}
411
412template <class _Rep, class _Period, class _Predicate>
413inline
414bool
415condition_variable::wait_for(unique_lock<mutex>& __lk,
416                             const chrono::duration<_Rep, _Period>& __d,
417                             _Predicate __pred)
418{
419    return wait_until(__lk, chrono::steady_clock::now() + __d,
420                      _VSTD::move(__pred));
421}
422
423#endif // !_LIBCPP_HAS_NO_THREADS
424
425_LIBCPP_END_NAMESPACE_STD
426
427_LIBCPP_POP_MACROS
428
429#endif  // _LIBCPP___MUTEX_BASE
430