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      1 // -*- C++ -*-
      2 //===----------------------------------------------------------------------===//
      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_BASE
     12 #define _LIBCPP___MUTEX_BASE
     13 
     14 #include <__config>
     15 #include <chrono>
     16 #include <system_error>
     17 #include <__threading_support>
     18 
     19 
     20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     21 #pragma GCC system_header
     22 #endif
     23 
     24 _LIBCPP_PUSH_MACROS
     25 #include <__undef_macros>
     26 
     27 
     28 _LIBCPP_BEGIN_NAMESPACE_STD
     29 
     30 #ifndef _LIBCPP_HAS_NO_THREADS
     31 
     32 #ifndef _LIBCPP_THREAD_SAFETY_ANNOTATION
     33 #  ifdef _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
     34 #    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x) __attribute__((x))
     35 #  else
     36 #    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x)
     37 #  endif
     38 #endif  // _LIBCPP_THREAD_SAFETY_ANNOTATION
     39 
     40 class _LIBCPP_TYPE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(capability("mutex")) mutex
     41 {
     42 #ifndef _LIBCPP_CXX03_LANG
     43     __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER;
     44 #else
     45     __libcpp_mutex_t __m_;
     46 #endif
     47 
     48 public:
     49     _LIBCPP_INLINE_VISIBILITY
     50 #ifndef _LIBCPP_CXX03_LANG
     51     constexpr mutex() = default;
     52 #else
     53     mutex() _NOEXCEPT {__m_ = (__libcpp_mutex_t)_LIBCPP_MUTEX_INITIALIZER;}
     54 #endif
     55     ~mutex();
     56 
     57 private:
     58     mutex(const mutex&);// = delete;
     59     mutex& operator=(const mutex&);// = delete;
     60 
     61 public:
     62     void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability());
     63     bool try_lock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_capability(true));
     64     void unlock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability());
     65 
     66     typedef __libcpp_mutex_t* native_handle_type;
     67     _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__m_;}
     68 };
     69 
     70 static_assert(is_nothrow_default_constructible<mutex>::value,
     71               "the default constructor for std::mutex must be nothrow");
     72 
     73 struct _LIBCPP_TYPE_VIS defer_lock_t {};
     74 struct _LIBCPP_TYPE_VIS try_to_lock_t {};
     75 struct _LIBCPP_TYPE_VIS adopt_lock_t {};
     76 
     77 #if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_MUTEX)
     78 
     79 extern const defer_lock_t  defer_lock;
     80 extern const try_to_lock_t try_to_lock;
     81 extern const adopt_lock_t  adopt_lock;
     82 
     83 #else
     84 
     85 /* _LIBCPP_INLINE_VAR */ constexpr defer_lock_t  defer_lock  = defer_lock_t();
     86 /* _LIBCPP_INLINE_VAR */ constexpr try_to_lock_t try_to_lock = try_to_lock_t();
     87 /* _LIBCPP_INLINE_VAR */ constexpr adopt_lock_t  adopt_lock  = adopt_lock_t();
     88 
     89 #endif
     90 
     91 template <class _Mutex>
     92 class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable)
     93 lock_guard
     94 {
     95 public:
     96     typedef _Mutex mutex_type;
     97 
     98 private:
     99     mutex_type& __m_;
    100 public:
    101 
    102     _LIBCPP_INLINE_VISIBILITY
    103     explicit lock_guard(mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
    104         : __m_(__m) {__m_.lock();}
    105     _LIBCPP_INLINE_VISIBILITY
    106     lock_guard(mutex_type& __m, adopt_lock_t) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
    107         : __m_(__m) {}
    108     _LIBCPP_INLINE_VISIBILITY
    109     ~lock_guard() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
    110 
    111 private:
    112     lock_guard(lock_guard const&) _LIBCPP_EQUAL_DELETE;
    113     lock_guard& operator=(lock_guard const&) _LIBCPP_EQUAL_DELETE;
    114 };
    115 
    116 template <class _Mutex>
    117 class _LIBCPP_TEMPLATE_VIS unique_lock
    118 {
    119 public:
    120     typedef _Mutex mutex_type;
    121 
    122 private:
    123     mutex_type* __m_;
    124     bool __owns_;
    125 
    126 public:
    127     _LIBCPP_INLINE_VISIBILITY
    128     unique_lock() _NOEXCEPT : __m_(nullptr), __owns_(false) {}
    129     _LIBCPP_INLINE_VISIBILITY
    130     explicit unique_lock(mutex_type& __m)
    131         : __m_(_VSTD::addressof(__m)), __owns_(true) {__m_->lock();}
    132     _LIBCPP_INLINE_VISIBILITY
    133     unique_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
    134         : __m_(_VSTD::addressof(__m)), __owns_(false) {}
    135     _LIBCPP_INLINE_VISIBILITY
    136     unique_lock(mutex_type& __m, try_to_lock_t)
    137         : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock()) {}
    138     _LIBCPP_INLINE_VISIBILITY
    139     unique_lock(mutex_type& __m, adopt_lock_t)
    140         : __m_(_VSTD::addressof(__m)), __owns_(true) {}
    141     template <class _Clock, class _Duration>
    142     _LIBCPP_INLINE_VISIBILITY
    143         unique_lock(mutex_type& __m, const chrono::time_point<_Clock, _Duration>& __t)
    144             : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_until(__t)) {}
    145     template <class _Rep, class _Period>
    146     _LIBCPP_INLINE_VISIBILITY
    147         unique_lock(mutex_type& __m, const chrono::duration<_Rep, _Period>& __d)
    148             : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_for(__d)) {}
    149     _LIBCPP_INLINE_VISIBILITY
    150     ~unique_lock()
    151     {
    152         if (__owns_)
    153             __m_->unlock();
    154     }
    155 
    156 private:
    157     unique_lock(unique_lock const&); // = delete;
    158     unique_lock& operator=(unique_lock const&); // = delete;
    159 
    160 public:
    161 #ifndef _LIBCPP_CXX03_LANG
    162     _LIBCPP_INLINE_VISIBILITY
    163     unique_lock(unique_lock&& __u) _NOEXCEPT
    164         : __m_(__u.__m_), __owns_(__u.__owns_)
    165         {__u.__m_ = nullptr; __u.__owns_ = false;}
    166     _LIBCPP_INLINE_VISIBILITY
    167     unique_lock& operator=(unique_lock&& __u) _NOEXCEPT
    168         {
    169             if (__owns_)
    170                 __m_->unlock();
    171             __m_ = __u.__m_;
    172             __owns_ = __u.__owns_;
    173             __u.__m_ = nullptr;
    174             __u.__owns_ = false;
    175             return *this;
    176         }
    177 
    178 #endif  // _LIBCPP_CXX03_LANG
    179 
    180     void lock();
    181     bool try_lock();
    182 
    183     template <class _Rep, class _Period>
    184         bool try_lock_for(const chrono::duration<_Rep, _Period>& __d);
    185     template <class _Clock, class _Duration>
    186         bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
    187 
    188     void unlock();
    189 
    190     _LIBCPP_INLINE_VISIBILITY
    191     void swap(unique_lock& __u) _NOEXCEPT
    192     {
    193         _VSTD::swap(__m_, __u.__m_);
    194         _VSTD::swap(__owns_, __u.__owns_);
    195     }
    196     _LIBCPP_INLINE_VISIBILITY
    197     mutex_type* release() _NOEXCEPT
    198     {
    199         mutex_type* __m = __m_;
    200         __m_ = nullptr;
    201         __owns_ = false;
    202         return __m;
    203     }
    204 
    205     _LIBCPP_INLINE_VISIBILITY
    206     bool owns_lock() const _NOEXCEPT {return __owns_;}
    207     _LIBCPP_INLINE_VISIBILITY
    208     _LIBCPP_EXPLICIT
    209         operator bool () const _NOEXCEPT {return __owns_;}
    210     _LIBCPP_INLINE_VISIBILITY
    211     mutex_type* mutex() const _NOEXCEPT {return __m_;}
    212 };
    213 
    214 template <class _Mutex>
    215 void
    216 unique_lock<_Mutex>::lock()
    217 {
    218     if (__m_ == nullptr)
    219         __throw_system_error(EPERM, "unique_lock::lock: references null mutex");
    220     if (__owns_)
    221         __throw_system_error(EDEADLK, "unique_lock::lock: already locked");
    222     __m_->lock();
    223     __owns_ = true;
    224 }
    225 
    226 template <class _Mutex>
    227 bool
    228 unique_lock<_Mutex>::try_lock()
    229 {
    230     if (__m_ == nullptr)
    231         __throw_system_error(EPERM, "unique_lock::try_lock: references null mutex");
    232     if (__owns_)
    233         __throw_system_error(EDEADLK, "unique_lock::try_lock: already locked");
    234     __owns_ = __m_->try_lock();
    235     return __owns_;
    236 }
    237 
    238 template <class _Mutex>
    239 template <class _Rep, class _Period>
    240 bool
    241 unique_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d)
    242 {
    243     if (__m_ == nullptr)
    244         __throw_system_error(EPERM, "unique_lock::try_lock_for: references null mutex");
    245     if (__owns_)
    246         __throw_system_error(EDEADLK, "unique_lock::try_lock_for: already locked");
    247     __owns_ = __m_->try_lock_for(__d);
    248     return __owns_;
    249 }
    250 
    251 template <class _Mutex>
    252 template <class _Clock, class _Duration>
    253 bool
    254 unique_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
    255 {
    256     if (__m_ == nullptr)
    257         __throw_system_error(EPERM, "unique_lock::try_lock_until: references null mutex");
    258     if (__owns_)
    259         __throw_system_error(EDEADLK, "unique_lock::try_lock_until: already locked");
    260     __owns_ = __m_->try_lock_until(__t);
    261     return __owns_;
    262 }
    263 
    264 template <class _Mutex>
    265 void
    266 unique_lock<_Mutex>::unlock()
    267 {
    268     if (!__owns_)
    269         __throw_system_error(EPERM, "unique_lock::unlock: not locked");
    270     __m_->unlock();
    271     __owns_ = false;
    272 }
    273 
    274 template <class _Mutex>
    275 inline _LIBCPP_INLINE_VISIBILITY
    276 void
    277 swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) _NOEXCEPT
    278     {__x.swap(__y);}
    279 
    280 //enum class cv_status
    281 _LIBCPP_DECLARE_STRONG_ENUM(cv_status)
    282 {
    283     no_timeout,
    284     timeout
    285 };
    286 _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)
    287 
    288 class _LIBCPP_TYPE_VIS condition_variable
    289 {
    290 #ifndef _LIBCPP_CXX03_LANG
    291     __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
    292 #else
    293     __libcpp_condvar_t __cv_;
    294 #endif
    295 
    296 public:
    297     _LIBCPP_INLINE_VISIBILITY
    298 #ifndef _LIBCPP_CXX03_LANG
    299     constexpr condition_variable() _NOEXCEPT = default;
    300 #else
    301     condition_variable() _NOEXCEPT {__cv_ = (__libcpp_condvar_t)_LIBCPP_CONDVAR_INITIALIZER;}
    302 #endif
    303     ~condition_variable();
    304 
    305 private:
    306     condition_variable(const condition_variable&); // = delete;
    307     condition_variable& operator=(const condition_variable&); // = delete;
    308 
    309 public:
    310     void notify_one() _NOEXCEPT;
    311     void notify_all() _NOEXCEPT;
    312 
    313     void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
    314     template <class _Predicate>
    315         _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
    316         void wait(unique_lock<mutex>& __lk, _Predicate __pred);
    317 
    318     template <class _Clock, class _Duration>
    319         _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
    320         cv_status
    321         wait_until(unique_lock<mutex>& __lk,
    322                    const chrono::time_point<_Clock, _Duration>& __t);
    323 
    324     template <class _Clock, class _Duration, class _Predicate>
    325         _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
    326         bool
    327         wait_until(unique_lock<mutex>& __lk,
    328                    const chrono::time_point<_Clock, _Duration>& __t,
    329                    _Predicate __pred);
    330 
    331     template <class _Rep, class _Period>
    332         _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
    333         cv_status
    334         wait_for(unique_lock<mutex>& __lk,
    335                  const chrono::duration<_Rep, _Period>& __d);
    336 
    337     template <class _Rep, class _Period, class _Predicate>
    338         bool
    339         _LIBCPP_INLINE_VISIBILITY
    340         wait_for(unique_lock<mutex>& __lk,
    341                  const chrono::duration<_Rep, _Period>& __d,
    342                  _Predicate __pred);
    343 
    344     typedef __libcpp_condvar_t* native_handle_type;
    345     _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__cv_;}
    346 
    347 private:
    348     void __do_timed_wait(unique_lock<mutex>& __lk,
    349        chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;
    350 };
    351 #endif // !_LIBCPP_HAS_NO_THREADS
    352 
    353 template <class _To, class _Rep, class _Period>
    354 inline _LIBCPP_INLINE_VISIBILITY
    355 typename enable_if
    356 <
    357     chrono::__is_duration<_To>::value,
    358     _To
    359 >::type
    360 __ceil(chrono::duration<_Rep, _Period> __d)
    361 {
    362     using namespace chrono;
    363     _To __r = duration_cast<_To>(__d);
    364     if (__r < __d)
    365         ++__r;
    366     return __r;
    367 }
    368 
    369 #ifndef _LIBCPP_HAS_NO_THREADS
    370 template <class _Predicate>
    371 void
    372 condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred)
    373 {
    374     while (!__pred())
    375         wait(__lk);
    376 }
    377 
    378 template <class _Clock, class _Duration>
    379 cv_status
    380 condition_variable::wait_until(unique_lock<mutex>& __lk,
    381                                const chrono::time_point<_Clock, _Duration>& __t)
    382 {
    383     using namespace chrono;
    384     wait_for(__lk, __t - _Clock::now());
    385     return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout;
    386 }
    387 
    388 template <class _Clock, class _Duration, class _Predicate>
    389 bool
    390 condition_variable::wait_until(unique_lock<mutex>& __lk,
    391                    const chrono::time_point<_Clock, _Duration>& __t,
    392                    _Predicate __pred)
    393 {
    394     while (!__pred())
    395     {
    396         if (wait_until(__lk, __t) == cv_status::timeout)
    397             return __pred();
    398     }
    399     return true;
    400 }
    401 
    402 template <class _Rep, class _Period>
    403 cv_status
    404 condition_variable::wait_for(unique_lock<mutex>& __lk,
    405                              const chrono::duration<_Rep, _Period>& __d)
    406 {
    407     using namespace chrono;
    408     if (__d <= __d.zero())
    409         return cv_status::timeout;
    410     typedef time_point<system_clock, duration<long double, nano> > __sys_tpf;
    411     typedef time_point<system_clock, nanoseconds> __sys_tpi;
    412     __sys_tpf _Max = __sys_tpi::max();
    413     steady_clock::time_point __c_now = steady_clock::now();
    414     system_clock::time_point __s_now = system_clock::now();
    415     if (_Max - __d > __s_now)
    416         __do_timed_wait(__lk, __s_now + __ceil<nanoseconds>(__d));
    417     else
    418         __do_timed_wait(__lk, __sys_tpi::max());
    419     return steady_clock::now() - __c_now < __d ? cv_status::no_timeout :
    420                                                  cv_status::timeout;
    421 }
    422 
    423 template <class _Rep, class _Period, class _Predicate>
    424 inline
    425 bool
    426 condition_variable::wait_for(unique_lock<mutex>& __lk,
    427                              const chrono::duration<_Rep, _Period>& __d,
    428                              _Predicate __pred)
    429 {
    430     return wait_until(__lk, chrono::steady_clock::now() + __d,
    431                       _VSTD::move(__pred));
    432 }
    433 
    434 #endif // !_LIBCPP_HAS_NO_THREADS
    435 
    436 _LIBCPP_END_NAMESPACE_STD
    437 
    438 _LIBCPP_POP_MACROS
    439 
    440 #endif  // _LIBCPP___MUTEX_BASE
    441