| // Support for concurrent programing -*- C++ -*- |
| |
| // Copyright (C) 2003, 2004, 2005, 2006 |
| // 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 2, 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. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING. If not, write to the Free |
| // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, |
| // USA. |
| |
| // As a special exception, you may use this file as part of a free software |
| // library without restriction. Specifically, if other files instantiate |
| // templates or use macros or inline functions from this file, or you compile |
| // this file and link it with other files to produce an executable, this |
| // file does not by itself cause the resulting executable to be covered by |
| // the GNU General Public License. This exception does not however |
| // invalidate any other reasons why the executable file might be covered by |
| // the GNU General Public License. |
| |
| /** @file concurrence.h |
| * This is an internal header file, included by other library headers. |
| * You should not attempt to use it directly. |
| */ |
| |
| #ifndef _CONCURRENCE_H |
| #define _CONCURRENCE_H 1 |
| |
| #include <cstdlib> |
| #include <exception> |
| #include <bits/gthr.h> |
| #include <bits/functexcept.h> |
| |
| _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) |
| |
| // 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 concurrance.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 = |
| #ifdef __GTHREADS |
| // NB: This macro doesn't actually exist yet in the compiler, but is |
| // set somewhat haphazardly at configure time. |
| #ifdef _GLIBCXX_ATOMIC_BUILTINS |
| _S_atomic; |
| #else |
| _S_mutex; |
| #endif |
| #else |
| _S_single; |
| #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"; } |
| }; |
| |
| // Substitute for concurrence_error object in the case of -fno-exceptions. |
| inline void |
| __throw_concurrence_lock_error() |
| { |
| #if __EXCEPTIONS |
| throw __concurrence_lock_error(); |
| #else |
| std::abort(); |
| #endif |
| } |
| |
| inline void |
| __throw_concurrence_unlock_error() |
| { |
| #if __EXCEPTIONS |
| throw __concurrence_unlock_error(); |
| #else |
| std::abort(); |
| #endif |
| } |
| |
| class __mutex |
| { |
| private: |
| __gthread_mutex_t _M_mutex; |
| |
| __mutex(const __mutex&); |
| __mutex& operator=(const __mutex&); |
| |
| public: |
| __mutex() |
| { |
| #if __GTHREADS |
| if (__gthread_active_p()) |
| { |
| #if defined __GTHREAD_MUTEX_INIT |
| __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT; |
| _M_mutex = __tmp; |
| #else |
| __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex); |
| #endif |
| } |
| #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 |
| } |
| }; |
| |
| class __recursive_mutex |
| { |
| private: |
| __gthread_recursive_mutex_t _M_mutex; |
| |
| __recursive_mutex(const __recursive_mutex&); |
| __recursive_mutex& operator=(const __recursive_mutex&); |
| |
| public: |
| __recursive_mutex() |
| { |
| #if __GTHREADS |
| if (__gthread_active_p()) |
| { |
| #if defined __GTHREAD_RECURSIVE_MUTEX_INIT |
| __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT; |
| _M_mutex = __tmp; |
| #else |
| __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex); |
| #endif |
| } |
| #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 |
| } |
| }; |
| |
| /// @brief 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(); } |
| }; |
| |
| _GLIBCXX_END_NAMESPACE |
| |
| #endif |