// Support for concurrent programing -*- C++ -*- // Copyright (C) 2003-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** @file ext/concurrence.h * This file is a GNU extension to the Standard C++ Library. */ #ifndef _CONCURRENCE_H #define _CONCURRENCE_H 1 #pragma GCC system_header #include <exception> #include <bits/gthr.h> #include <bits/functexcept.h> #include <bits/cpp_type_traits.h> #include <ext/type_traits.h> namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION // Available locking policies: // _S_single single-threaded code that doesn't need to be locked. // _S_mutex multi-threaded code that requires additional support // from gthr.h or abstraction layers in concurrence.h. // _S_atomic multi-threaded code using atomic operations. enum _Lock_policy { _S_single, _S_mutex, _S_atomic }; // Compile time constant that indicates prefered locking policy in // the current configuration. static const _Lock_policy __default_lock_policy = #ifndef __GTHREADS _S_single; #elif defined _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY _S_atomic; #else _S_mutex; #endif // NB: As this is used in libsupc++, need to only depend on // exception. No stdexception classes, no use of std::string. class __concurrence_lock_error : public std::exception { public: virtual char const* what() const throw() { return "__gnu_cxx::__concurrence_lock_error"; } }; class __concurrence_unlock_error : public std::exception { public: virtual char const* what() const throw() { return "__gnu_cxx::__concurrence_unlock_error"; } }; class __concurrence_broadcast_error : public std::exception { public: virtual char const* what() const throw() { return "__gnu_cxx::__concurrence_broadcast_error"; } }; class __concurrence_wait_error : public std::exception { public: virtual char const* what() const throw() { return "__gnu_cxx::__concurrence_wait_error"; } }; // Substitute for concurrence_error object in the case of -fno-exceptions. inline void __throw_concurrence_lock_error() { _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); } inline void __throw_concurrence_unlock_error() { _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); } #ifdef __GTHREAD_HAS_COND inline void __throw_concurrence_broadcast_error() { _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); } inline void __throw_concurrence_wait_error() { _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); } #endif class __mutex { private: #if __GTHREADS && defined __GTHREAD_MUTEX_INIT __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT; #else __gthread_mutex_t _M_mutex; #endif __mutex(const __mutex&); __mutex& operator=(const __mutex&); public: __mutex() { #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT if (__gthread_active_p()) __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex); #endif } #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT ~__mutex() { if (__gthread_active_p()) __gthread_mutex_destroy(&_M_mutex); } #endif void lock() { #if __GTHREADS if (__gthread_active_p()) { if (__gthread_mutex_lock(&_M_mutex) != 0) __throw_concurrence_lock_error(); } #endif } void unlock() { #if __GTHREADS if (__gthread_active_p()) { if (__gthread_mutex_unlock(&_M_mutex) != 0) __throw_concurrence_unlock_error(); } #endif } __gthread_mutex_t* gthread_mutex(void) { return &_M_mutex; } }; class __recursive_mutex { private: #if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT; #else __gthread_recursive_mutex_t _M_mutex; #endif __recursive_mutex(const __recursive_mutex&); __recursive_mutex& operator=(const __recursive_mutex&); public: __recursive_mutex() { #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT if (__gthread_active_p()) __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex); #endif } #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT ~__recursive_mutex() { if (__gthread_active_p()) __gthread_recursive_mutex_destroy(&_M_mutex); } #endif void lock() { #if __GTHREADS if (__gthread_active_p()) { if (__gthread_recursive_mutex_lock(&_M_mutex) != 0) __throw_concurrence_lock_error(); } #endif } void unlock() { #if __GTHREADS if (__gthread_active_p()) { if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0) __throw_concurrence_unlock_error(); } #endif } __gthread_recursive_mutex_t* gthread_recursive_mutex(void) { return &_M_mutex; } }; /// Scoped lock idiom. // Acquire the mutex here with a constructor call, then release with // the destructor call in accordance with RAII style. class __scoped_lock { public: typedef __mutex __mutex_type; private: __mutex_type& _M_device; __scoped_lock(const __scoped_lock&); __scoped_lock& operator=(const __scoped_lock&); public: explicit __scoped_lock(__mutex_type& __name) : _M_device(__name) { _M_device.lock(); } ~__scoped_lock() throw() { _M_device.unlock(); } }; #ifdef __GTHREAD_HAS_COND class __cond { private: #if __GTHREADS && defined __GTHREAD_COND_INIT __gthread_cond_t _M_cond = __GTHREAD_COND_INIT; #else __gthread_cond_t _M_cond; #endif __cond(const __cond&); __cond& operator=(const __cond&); public: __cond() { #if __GTHREADS && ! defined __GTHREAD_COND_INIT if (__gthread_active_p()) __GTHREAD_COND_INIT_FUNCTION(&_M_cond); #endif } #if __GTHREADS && ! defined __GTHREAD_COND_INIT ~__cond() { if (__gthread_active_p()) __gthread_cond_destroy(&_M_cond); } #endif void broadcast() { #if __GTHREADS if (__gthread_active_p()) { if (__gthread_cond_broadcast(&_M_cond) != 0) __throw_concurrence_broadcast_error(); } #endif } void wait(__mutex *mutex) { #if __GTHREADS { if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0) __throw_concurrence_wait_error(); } #endif } void wait_recursive(__recursive_mutex *mutex) { #if __GTHREADS { if (__gthread_cond_wait_recursive(&_M_cond, mutex->gthread_recursive_mutex()) != 0) __throw_concurrence_wait_error(); } #endif } }; #endif _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif