libcxx/include/__mutex/unique_lock.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___MUTEX_UNIQUE_LOCK_H
  10 #define _LIBCPP___MUTEX_UNIQUE_LOCK_H
  11
  12 #include <__chrono/duration.h>
  13 #include <__chrono/time_point.h>
  14 #include <__config>
  15 #include <__memory/addressof.h>
  16 #include <__mutex/tag_types.h>
  17 #include <__system_error/system_error.h>
  18 #include <__utility/swap.h>
  19 #include <cerrno>
  20
  21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  22 #  pragma GCC system_header
  23 #endif
  24
  25 #ifndef _LIBCPP_HAS_NO_THREADS
  26
  27 _LIBCPP_BEGIN_NAMESPACE_STD
  28
  29 template <class _Mutex>
  30 class _LIBCPP_TEMPLATE_VIS unique_lock {
  31 public:
  32   typedef _Mutex mutex_type;
  33
  34 private:
  35   mutex_type* __m_;
  36   bool __owns_;
  37
  38 public:
  39   _LIBCPP_HIDE_FROM_ABI unique_lock() _NOEXCEPT : __m_(nullptr), __owns_(false) {}
  40   _LIBCPP_HIDE_FROM_ABI explicit unique_lock(mutex_type& __m) : __m_(std::addressof(__m)), __owns_(true) {
  41     __m_->lock();
  42   }
  43
  44   _LIBCPP_HIDE_FROM_ABI unique_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
  45       : __m_(std::addressof(__m)),
  46         __owns_(false) {}
  47
  48   _LIBCPP_HIDE_FROM_ABI unique_lock(mutex_type& __m, try_to_lock_t)
  49       : __m_(std::addressof(__m)), __owns_(__m.try_lock()) {}
  50
  51   _LIBCPP_HIDE_FROM_ABI unique_lock(mutex_type& __m, adopt_lock_t) : __m_(std::addressof(__m)), __owns_(true) {}
  52
  53   template <class _Clock, class _Duration>
  54   _LIBCPP_HIDE_FROM_ABI unique_lock(mutex_type& __m, const chrono::time_point<_Clock, _Duration>& __t)
  55       : __m_(std::addressof(__m)), __owns_(__m.try_lock_until(__t)) {}
  56
  57   template <class _Rep, class _Period>
  58   _LIBCPP_HIDE_FROM_ABI unique_lock(mutex_type& __m, const chrono::duration<_Rep, _Period>& __d)
  59       : __m_(std::addressof(__m)), __owns_(__m.try_lock_for(__d)) {}
  60
  61   _LIBCPP_HIDE_FROM_ABI ~unique_lock() {
  62     if (__owns_)
  63       __m_->unlock();
  64   }
  65
  66   unique_lock(unique_lock const&)            = delete;
  67   unique_lock& operator=(unique_lock const&) = delete;
  68
  69   _LIBCPP_HIDE_FROM_ABI unique_lock(unique_lock&& __u) _NOEXCEPT : __m_(__u.__m_), __owns_(__u.__owns_) {
  70     __u.__m_    = nullptr;
  71     __u.__owns_ = false;
  72   }
  73
  74   _LIBCPP_HIDE_FROM_ABI unique_lock& operator=(unique_lock&& __u) _NOEXCEPT {
  75     if (__owns_)
  76       __m_->unlock();
  77
  78     __m_        = __u.__m_;
  79     __owns_     = __u.__owns_;
  80     __u.__m_    = nullptr;
  81     __u.__owns_ = false;
  82     return *this;
  83   }
  84
  85   void lock();
  86   bool try_lock();
  87
  88   template <class _Rep, class _Period>
  89   bool try_lock_for(const chrono::duration<_Rep, _Period>& __d);
  90
  91   template <class _Clock, class _Duration>
  92   bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
  93
  94   void unlock();
  95
  96   _LIBCPP_HIDE_FROM_ABI void swap(unique_lock& __u) _NOEXCEPT {
  97     std::swap(__m_, __u.__m_);
  98     std::swap(__owns_, __u.__owns_);
  99   }
 100
 101   _LIBCPP_HIDE_FROM_ABI mutex_type* release() _NOEXCEPT {
 102     mutex_type* __m = __m_;
 103     __m_            = nullptr;
 104     __owns_         = false;
 105     return __m;
 106   }
 107
 108   _LIBCPP_HIDE_FROM_ABI bool owns_lock() const _NOEXCEPT { return __owns_; }
 109   _LIBCPP_HIDE_FROM_ABI explicit operator bool() const _NOEXCEPT { return __owns_; }
 110   _LIBCPP_HIDE_FROM_ABI mutex_type* mutex() const _NOEXCEPT { return __m_; }
 111 };
 112 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(unique_lock);
 113
 114 template <class _Mutex>
 115 void unique_lock<_Mutex>::lock() {
 116   if (__m_ == nullptr)
 117     __throw_system_error(EPERM, "unique_lock::lock: references null mutex");
 118   if (__owns_)
 119     __throw_system_error(EDEADLK, "unique_lock::lock: already locked");
 120   __m_->lock();
 121   __owns_ = true;
 122 }
 123
 124 template <class _Mutex>
 125 bool unique_lock<_Mutex>::try_lock() {
 126   if (__m_ == nullptr)
 127     __throw_system_error(EPERM, "unique_lock::try_lock: references null mutex");
 128   if (__owns_)
 129     __throw_system_error(EDEADLK, "unique_lock::try_lock: already locked");
 130   __owns_ = __m_->try_lock();
 131   return __owns_;
 132 }
 133
 134 template <class _Mutex>
 135 template <class _Rep, class _Period>
 136 bool unique_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d) {
 137   if (__m_ == nullptr)
 138     __throw_system_error(EPERM, "unique_lock::try_lock_for: references null mutex");
 139   if (__owns_)
 140     __throw_system_error(EDEADLK, "unique_lock::try_lock_for: already locked");
 141   __owns_ = __m_->try_lock_for(__d);
 142   return __owns_;
 143 }
 144
 145 template <class _Mutex>
 146 template <class _Clock, class _Duration>
 147 bool unique_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t) {
 148   if (__m_ == nullptr)
 149     __throw_system_error(EPERM, "unique_lock::try_lock_until: references null mutex");
 150   if (__owns_)
 151     __throw_system_error(EDEADLK, "unique_lock::try_lock_until: already locked");
 152   __owns_ = __m_->try_lock_until(__t);
 153   return __owns_;
 154 }
 155
 156 template <class _Mutex>
 157 void unique_lock<_Mutex>::unlock() {
 158   if (!__owns_)
 159     __throw_system_error(EPERM, "unique_lock::unlock: not locked");
 160   __m_->unlock();
 161   __owns_ = false;
 162 }
 163
 164 template <class _Mutex>
 165 inline _LIBCPP_HIDE_FROM_ABI void swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) _NOEXCEPT {
 166   __x.swap(__y);
 167 }
 168
 169 _LIBCPP_END_NAMESPACE_STD
 170
 171 #endif // _LIBCPP_HAS_NO_THREADS
 172
 173 #endif // _LIBCPP___MUTEX_UNIQUE_LOCK_H