1 // Support for pointer abstractions -*- C++ -*- 2 3 // Copyright (C) 2011-2018 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 #include <memory> 26 27 #include "mutex_pool.h" 28 29 namespace __gnu_internal _GLIBCXX_VISIBILITY(hidden) 30 { 31 /* Returns different instances of __mutex depending on the passed index 32 * in order to limit contention. 33 */ 34 __gnu_cxx::__mutex& 35 get_mutex(unsigned char i) 36 { 37 static __gnu_cxx::__mutex m[mask + 1]; 38 return m[i]; 39 } 40 } 41 42 namespace std _GLIBCXX_VISIBILITY(default) 43 { 44 _GLIBCXX_BEGIN_NAMESPACE_VERSION 45 46 bad_weak_ptr::~bad_weak_ptr() noexcept = default; 47 48 char const* 49 bad_weak_ptr::what() const noexcept 50 { return "bad_weak_ptr"; } 51 52 #ifdef __GTHREADS 53 namespace 54 { 55 inline unsigned char key(const void* addr) 56 { return _Hash_impl::hash(addr) & __gnu_internal::mask; } 57 } 58 59 _Sp_locker::_Sp_locker(const void* p) noexcept 60 { 61 if (__gthread_active_p()) 62 { 63 _M_key1 = _M_key2 = key(p); 64 __gnu_internal::get_mutex(_M_key1).lock(); 65 } 66 else 67 _M_key1 = _M_key2 = __gnu_internal::invalid; 68 } 69 70 _Sp_locker::_Sp_locker(const void* p1, const void* p2) noexcept 71 { 72 if (__gthread_active_p()) 73 { 74 _M_key1 = key(p1); 75 _M_key2 = key(p2); 76 if (_M_key2 < _M_key1) 77 __gnu_internal::get_mutex(_M_key2).lock(); 78 __gnu_internal::get_mutex(_M_key1).lock(); 79 if (_M_key2 > _M_key1) 80 __gnu_internal::get_mutex(_M_key2).lock(); 81 } 82 else 83 _M_key1 = _M_key2 = __gnu_internal::invalid; 84 } 85 86 _Sp_locker::~_Sp_locker() 87 { 88 if (_M_key1 != __gnu_internal::invalid) 89 { 90 __gnu_internal::get_mutex(_M_key1).unlock(); 91 if (_M_key2 != _M_key1) 92 __gnu_internal::get_mutex(_M_key2).unlock(); 93 } 94 } 95 #endif 96 97 _GLIBCXX_END_NAMESPACE_VERSION 98 } // namespace 99