libstdc++
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00001 // std::unique_lock implementation -*- C++ -*- 00002 00003 // Copyright (C) 2008-2019 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file bits/unique_lock.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{mutex} 00028 */ 00029 00030 #ifndef _GLIBCXX_UNIQUE_LOCK_H 00031 #define _GLIBCXX_UNIQUE_LOCK_H 1 00032 00033 #pragma GCC system_header 00034 00035 #if __cplusplus < 201103L 00036 # include <bits/c++0x_warning.h> 00037 #else 00038 00039 #include <chrono> 00040 #include <bits/move.h> // for std::swap 00041 00042 namespace std _GLIBCXX_VISIBILITY(default) 00043 { 00044 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00045 00046 /** 00047 * @ingroup mutexes 00048 * @{ 00049 */ 00050 00051 /** @brief A movable scoped lock type. 00052 * 00053 * A unique_lock controls mutex ownership within a scope. Ownership of the 00054 * mutex can be delayed until after construction and can be transferred 00055 * to another unique_lock by move construction or move assignment. If a 00056 * mutex lock is owned when the destructor runs ownership will be released. 00057 */ 00058 template<typename _Mutex> 00059 class unique_lock 00060 { 00061 public: 00062 typedef _Mutex mutex_type; 00063 00064 unique_lock() noexcept 00065 : _M_device(0), _M_owns(false) 00066 { } 00067 00068 explicit unique_lock(mutex_type& __m) 00069 : _M_device(std::__addressof(__m)), _M_owns(false) 00070 { 00071 lock(); 00072 _M_owns = true; 00073 } 00074 00075 unique_lock(mutex_type& __m, defer_lock_t) noexcept 00076 : _M_device(std::__addressof(__m)), _M_owns(false) 00077 { } 00078 00079 unique_lock(mutex_type& __m, try_to_lock_t) 00080 : _M_device(std::__addressof(__m)), _M_owns(_M_device->try_lock()) 00081 { } 00082 00083 unique_lock(mutex_type& __m, adopt_lock_t) noexcept 00084 : _M_device(std::__addressof(__m)), _M_owns(true) 00085 { 00086 // XXX calling thread owns mutex 00087 } 00088 00089 template<typename _Clock, typename _Duration> 00090 unique_lock(mutex_type& __m, 00091 const chrono::time_point<_Clock, _Duration>& __atime) 00092 : _M_device(std::__addressof(__m)), 00093 _M_owns(_M_device->try_lock_until(__atime)) 00094 { } 00095 00096 template<typename _Rep, typename _Period> 00097 unique_lock(mutex_type& __m, 00098 const chrono::duration<_Rep, _Period>& __rtime) 00099 : _M_device(std::__addressof(__m)), 00100 _M_owns(_M_device->try_lock_for(__rtime)) 00101 { } 00102 00103 ~unique_lock() 00104 { 00105 if (_M_owns) 00106 unlock(); 00107 } 00108 00109 unique_lock(const unique_lock&) = delete; 00110 unique_lock& operator=(const unique_lock&) = delete; 00111 00112 unique_lock(unique_lock&& __u) noexcept 00113 : _M_device(__u._M_device), _M_owns(__u._M_owns) 00114 { 00115 __u._M_device = 0; 00116 __u._M_owns = false; 00117 } 00118 00119 unique_lock& operator=(unique_lock&& __u) noexcept 00120 { 00121 if(_M_owns) 00122 unlock(); 00123 00124 unique_lock(std::move(__u)).swap(*this); 00125 00126 __u._M_device = 0; 00127 __u._M_owns = false; 00128 00129 return *this; 00130 } 00131 00132 void 00133 lock() 00134 { 00135 if (!_M_device) 00136 __throw_system_error(int(errc::operation_not_permitted)); 00137 else if (_M_owns) 00138 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00139 else 00140 { 00141 _M_device->lock(); 00142 _M_owns = true; 00143 } 00144 } 00145 00146 bool 00147 try_lock() 00148 { 00149 if (!_M_device) 00150 __throw_system_error(int(errc::operation_not_permitted)); 00151 else if (_M_owns) 00152 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00153 else 00154 { 00155 _M_owns = _M_device->try_lock(); 00156 return _M_owns; 00157 } 00158 } 00159 00160 template<typename _Clock, typename _Duration> 00161 bool 00162 try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime) 00163 { 00164 if (!_M_device) 00165 __throw_system_error(int(errc::operation_not_permitted)); 00166 else if (_M_owns) 00167 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00168 else 00169 { 00170 _M_owns = _M_device->try_lock_until(__atime); 00171 return _M_owns; 00172 } 00173 } 00174 00175 template<typename _Rep, typename _Period> 00176 bool 00177 try_lock_for(const chrono::duration<_Rep, _Period>& __rtime) 00178 { 00179 if (!_M_device) 00180 __throw_system_error(int(errc::operation_not_permitted)); 00181 else if (_M_owns) 00182 __throw_system_error(int(errc::resource_deadlock_would_occur)); 00183 else 00184 { 00185 _M_owns = _M_device->try_lock_for(__rtime); 00186 return _M_owns; 00187 } 00188 } 00189 00190 void 00191 unlock() 00192 { 00193 if (!_M_owns) 00194 __throw_system_error(int(errc::operation_not_permitted)); 00195 else if (_M_device) 00196 { 00197 _M_device->unlock(); 00198 _M_owns = false; 00199 } 00200 } 00201 00202 void 00203 swap(unique_lock& __u) noexcept 00204 { 00205 std::swap(_M_device, __u._M_device); 00206 std::swap(_M_owns, __u._M_owns); 00207 } 00208 00209 mutex_type* 00210 release() noexcept 00211 { 00212 mutex_type* __ret = _M_device; 00213 _M_device = 0; 00214 _M_owns = false; 00215 return __ret; 00216 } 00217 00218 bool 00219 owns_lock() const noexcept 00220 { return _M_owns; } 00221 00222 explicit operator bool() const noexcept 00223 { return owns_lock(); } 00224 00225 mutex_type* 00226 mutex() const noexcept 00227 { return _M_device; } 00228 00229 private: 00230 mutex_type* _M_device; 00231 bool _M_owns; 00232 }; 00233 00234 /// Swap overload for unique_lock objects. 00235 template<typename _Mutex> 00236 inline void 00237 swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept 00238 { __x.swap(__y); } 00239 00240 // @} group mutexes 00241 _GLIBCXX_END_NAMESPACE_VERSION 00242 } // namespace 00243 00244 #endif // C++11 00245 #endif // _GLIBCXX_UNIQUE_LOCK_H