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- // -*- C++ -*-
- // Module: Log4CPLUS
- // File: pointer.h
- // Created: 6/2001
- // Author: Tad E. Smith
- //
- //
- // Copyright 2001-2015 Tad E. Smith
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
- //
- // Note: Some of this code uses ideas from "More Effective C++" by Scott
- // Myers, Addison Wesley Longmain, Inc., (c) 1996, Chapter 29, pp. 183-213
- //
- /** @file */
- #ifndef LOG4CPLUS_HELPERS_POINTERS_HEADER_
- #define LOG4CPLUS_HELPERS_POINTERS_HEADER_
- #include <log4cplus/config.hxx>
- #if defined (LOG4CPLUS_HAVE_PRAGMA_ONCE)
- #pragma once
- #endif
- #include <log4cplus/thread/syncprims.h>
- #include <algorithm>
- #include <cassert>
- #if ! defined (LOG4CPLUS_SINGLE_THREADED) \
- && defined (LOG4CPLUS_HAVE_CXX11_ATOMICS)
- #include <atomic>
- #endif
- namespace log4cplus {
- namespace helpers {
- /******************************************************************************
- * Class SharedObject (from pp. 204-205) *
- ******************************************************************************/
- class LOG4CPLUS_EXPORT SharedObject
- {
- public:
- void addReference() const;
- void removeReference() const;
- protected:
- // Ctor
- SharedObject()
- : access_mutex()
- , count(0)
- { }
- SharedObject(const SharedObject&)
- : access_mutex()
- , count(0)
- { }
- // Dtor
- virtual ~SharedObject();
- // Operators
- SharedObject& operator=(const SharedObject&) { return *this; }
- public:
- thread::Mutex access_mutex;
- private:
- #if defined (LOG4CPLUS_SINGLE_THREADED)
- typedef unsigned count_type;
- #elif defined (LOG4CPLUS_HAVE_CXX11_ATOMICS)
- typedef std::atomic<unsigned> count_type;
- #elif defined (_WIN32) || defined (__CYGWIN__)
- typedef long count_type;
- #else
- typedef unsigned count_type;
- #endif
- mutable count_type count;
- };
- /******************************************************************************
- * Template Class SharedObjectPtr (from pp. 203, 206) *
- ******************************************************************************/
- template<class T>
- class SharedObjectPtr
- {
- public:
- // Ctor
- explicit
- SharedObjectPtr(T* realPtr = 0)
- : pointee(realPtr)
- {
- addref ();
- }
- SharedObjectPtr(const SharedObjectPtr& rhs)
- : pointee(rhs.pointee)
- {
- addref ();
- }
- #if defined (LOG4CPLUS_HAVE_RVALUE_REFS)
- SharedObjectPtr(SharedObjectPtr && rhs)
- : pointee (std::move (rhs.pointee))
- {
- rhs.pointee = 0;
- }
- SharedObjectPtr & operator = (SharedObjectPtr && rhs)
- {
- rhs.swap (*this);
- return *this;
- }
- #endif
- // Dtor
- ~SharedObjectPtr()
- {
- if (pointee)
- pointee->removeReference();
- }
- // Operators
- bool operator==(const SharedObjectPtr& rhs) const { return (pointee == rhs.pointee); }
- bool operator!=(const SharedObjectPtr& rhs) const { return (pointee != rhs.pointee); }
- bool operator==(const T* rhs) const { return (pointee == rhs); }
- bool operator!=(const T* rhs) const { return (pointee != rhs); }
- T* operator->() const {assert (pointee); return pointee; }
- T& operator*() const {assert (pointee); return *pointee; }
- SharedObjectPtr& operator=(const SharedObjectPtr& rhs)
- {
- return this->operator = (rhs.pointee);
- }
- SharedObjectPtr& operator=(T* rhs)
- {
- SharedObjectPtr<T> (rhs).swap (*this);
- return *this;
- }
- // Methods
- T* get() const { return pointee; }
- void swap (SharedObjectPtr & other) throw ()
- {
- std::swap (pointee, other.pointee);
- }
- typedef T * (SharedObjectPtr:: * unspec_bool_type) () const;
- operator unspec_bool_type () const
- {
- return pointee ? &SharedObjectPtr::get : 0;
- }
- bool operator ! () const
- {
- return ! pointee;
- }
- private:
- // Methods
- void addref() const
- {
- if (pointee)
- pointee->addReference();
- }
- // Data
- T* pointee;
- };
- //! Boost `intrusive_ptr` helpers.
- //! @{
- inline
- void
- intrusive_ptr_add_ref (SharedObject const * so)
- {
- so->addReference();
- }
- inline
- void
- intrusive_ptr_release (SharedObject const * so)
- {
- so->removeReference();
- }
- //! @}
- } // end namespace helpers
- } // end namespace log4cplus
- #endif // LOG4CPLUS_HELPERS_POINTERS_HEADER_
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