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Diffstat (limited to 'gcc-4.4.3/libstdc++-v3/include/tr1_impl/boost_sp_counted_base.h')
| -rw-r--r-- | gcc-4.4.3/libstdc++-v3/include/tr1_impl/boost_sp_counted_base.h | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/gcc-4.4.3/libstdc++-v3/include/tr1_impl/boost_sp_counted_base.h b/gcc-4.4.3/libstdc++-v3/include/tr1_impl/boost_sp_counted_base.h new file mode 100644 index 000000000..48e601f21 --- /dev/null +++ b/gcc-4.4.3/libstdc++-v3/include/tr1_impl/boost_sp_counted_base.h @@ -0,0 +1,239 @@ +// <tr1_impl/boost_sp_counted_base.h> -*- C++ -*- + +// Copyright (C) 2007, 2009 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/>. + +// shared_count.hpp +// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. + +// shared_ptr.hpp +// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes. +// Copyright (C) 2001, 2002, 2003 Peter Dimov + +// weak_ptr.hpp +// Copyright (C) 2001, 2002, 2003 Peter Dimov + +// enable_shared_from_this.hpp +// Copyright (C) 2002 Peter Dimov + +// Distributed under the Boost Software License, Version 1.0. (See +// accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) + +// GCC Note: based on version 1.32.0 of the Boost library. + +/** @file tr1_impl/boost_sp_counted_base.h + * This is an internal header file, included by other library headers. + * You should not attempt to use it directly. + */ + + +namespace std +{ +_GLIBCXX_BEGIN_NAMESPACE_TR1 + + class bad_weak_ptr : public std::exception + { + public: + virtual char const* + what() const throw() +#ifdef _GLIBCXX_INCLUDE_AS_CXX0X + { return "std::bad_weak_ptr"; } +#else + { return "tr1::bad_weak_ptr"; } +#endif + }; + + // Substitute for bad_weak_ptr object in the case of -fno-exceptions. + inline void + __throw_bad_weak_ptr() + { +#if __EXCEPTIONS + throw bad_weak_ptr(); +#else + __builtin_abort(); +#endif + } + + using __gnu_cxx::_Lock_policy; + using __gnu_cxx::__default_lock_policy; + using __gnu_cxx::_S_single; + using __gnu_cxx::_S_mutex; + using __gnu_cxx::_S_atomic; + + // Empty helper class except when the template argument is _S_mutex. + template<_Lock_policy _Lp> + class _Mutex_base + { + protected: + // The atomic policy uses fully-fenced builtins, single doesn't care. + enum { _S_need_barriers = 0 }; + }; + + template<> + class _Mutex_base<_S_mutex> + : public __gnu_cxx::__mutex + { + protected: + // This policy is used when atomic builtins are not available. + // The replacement atomic operations might not have the necessary + // memory barriers. + enum { _S_need_barriers = 1 }; + }; + + template<_Lock_policy _Lp = __default_lock_policy> + class _Sp_counted_base + : public _Mutex_base<_Lp> + { + public: + _Sp_counted_base() + : _M_use_count(1), _M_weak_count(1) { } + + virtual + ~_Sp_counted_base() // nothrow + { } + + // Called when _M_use_count drops to zero, to release the resources + // managed by *this. + virtual void + _M_dispose() = 0; // nothrow + + // Called when _M_weak_count drops to zero. + virtual void + _M_destroy() // nothrow + { delete this; } + + virtual void* + _M_get_deleter(const std::type_info&) = 0; + + void + _M_add_ref_copy() + { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); } + + void + _M_add_ref_lock(); + + void + _M_release() // nothrow + { + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1) + { + _M_dispose(); + // There must be a memory barrier between dispose() and destroy() + // to ensure that the effects of dispose() are observed in the + // thread that runs destroy(). + // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html + if (_Mutex_base<_Lp>::_S_need_barriers) + { + _GLIBCXX_READ_MEM_BARRIER; + _GLIBCXX_WRITE_MEM_BARRIER; + } + + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, + -1) == 1) + _M_destroy(); + } + } + + void + _M_weak_add_ref() // nothrow + { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); } + + void + _M_weak_release() // nothrow + { + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1) + { + if (_Mutex_base<_Lp>::_S_need_barriers) + { + // See _M_release(), + // destroy() must observe results of dispose() + _GLIBCXX_READ_MEM_BARRIER; + _GLIBCXX_WRITE_MEM_BARRIER; + } + _M_destroy(); + } + } + + long + _M_get_use_count() const // nothrow + { + // No memory barrier is used here so there is no synchronization + // with other threads. + return const_cast<const volatile _Atomic_word&>(_M_use_count); + } + + private: + _Sp_counted_base(_Sp_counted_base const&); + _Sp_counted_base& operator=(_Sp_counted_base const&); + + _Atomic_word _M_use_count; // #shared + _Atomic_word _M_weak_count; // #weak + (#shared != 0) + }; + + template<> + inline void + _Sp_counted_base<_S_single>:: + _M_add_ref_lock() + { + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0) + { + _M_use_count = 0; + __throw_bad_weak_ptr(); + } + } + + template<> + inline void + _Sp_counted_base<_S_mutex>:: + _M_add_ref_lock() + { + __gnu_cxx::__scoped_lock sentry(*this); + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0) + { + _M_use_count = 0; + __throw_bad_weak_ptr(); + } + } + + template<> + inline void + _Sp_counted_base<_S_atomic>:: + _M_add_ref_lock() + { + // Perform lock-free add-if-not-zero operation. + _Atomic_word __count; + do + { + __count = _M_use_count; + if (__count == 0) + __throw_bad_weak_ptr(); + + // Replace the current counter value with the old value + 1, as + // long as it's not changed meanwhile. + } + while (!__sync_bool_compare_and_swap(&_M_use_count, __count, + __count + 1)); + } + +_GLIBCXX_END_NAMESPACE_TR1 +} |