mirror of
https://github.com/zerotier/ZeroTierOne.git
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145 lines
3.5 KiB
C++
145 lines
3.5 KiB
C++
/*
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* ZeroTier One - Global Peer to Peer Ethernet
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* Copyright (C) 2011-2014 ZeroTier Networks LLC
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* --
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*
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* ZeroTier may be used and distributed under the terms of the GPLv3, which
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* are available at: http://www.gnu.org/licenses/gpl-3.0.html
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*
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* If you would like to embed ZeroTier into a commercial application or
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* redistribute it in a modified binary form, please contact ZeroTier Networks
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* LLC. Start here: http://www.zerotier.com/
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*/
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#ifndef ZT_SHAREDPTR_HPP
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#define ZT_SHAREDPTR_HPP
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#include "Mutex.hpp"
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#include "AtomicCounter.hpp"
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namespace ZeroTier {
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/**
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* Simple reference counted pointer
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*
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* This is an introspective shared pointer. Classes that need to be reference
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* counted must list this as a 'friend' and must have a private instance of
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* AtomicCounter called __refCount. They should also have private destructors,
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* since only this class should delete them.
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*
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* Because this is introspective, it is safe to apply to a naked pointer
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* multiple times provided there is always at least one holding SharedPtr.
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*
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* Once C++11 is ubiquitous, this and a few other things like Thread might get
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* torn out for their standard equivalents.
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*/
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template<typename T>
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class SharedPtr
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{
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public:
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SharedPtr()
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throw() :
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_ptr((T *)0)
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{
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}
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SharedPtr(T *obj)
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throw() :
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_ptr(obj)
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{
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++obj->__refCount;
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}
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SharedPtr(const SharedPtr &sp)
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throw() :
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_ptr(sp._getAndInc())
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{
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}
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~SharedPtr()
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{
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if (_ptr) {
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if (--_ptr->__refCount <= 0)
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delete _ptr;
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}
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}
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inline SharedPtr &operator=(const SharedPtr &sp)
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{
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if (_ptr != sp._ptr) {
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T *p = sp._getAndInc();
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if (_ptr) {
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if (--_ptr->__refCount <= 0)
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delete _ptr;
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}
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_ptr = p;
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}
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return *this;
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}
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inline void swap(SharedPtr &with)
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throw()
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{
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T *tmp = _ptr;
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_ptr = with._ptr;
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with._ptr = tmp;
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}
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inline operator bool() const throw() { return (_ptr != (T *)0); }
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inline T &operator*() const throw() { return *_ptr; }
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inline T *operator->() const throw() { return _ptr; }
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/**
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* @return Raw pointer to held object
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*/
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inline T *ptr() const throw() { return _ptr; }
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/**
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* Set this pointer to null
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*/
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inline void zero()
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{
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if (_ptr) {
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if (--_ptr->__refCount <= 0)
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delete _ptr;
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}
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_ptr = (T *)0;
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}
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inline bool operator==(const SharedPtr &sp) const throw() { return (_ptr == sp._ptr); }
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inline bool operator!=(const SharedPtr &sp) const throw() { return (_ptr != sp._ptr); }
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inline bool operator>(const SharedPtr &sp) const throw() { return (_ptr > sp._ptr); }
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inline bool operator<(const SharedPtr &sp) const throw() { return (_ptr < sp._ptr); }
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inline bool operator>=(const SharedPtr &sp) const throw() { return (_ptr >= sp._ptr); }
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inline bool operator<=(const SharedPtr &sp) const throw() { return (_ptr <= sp._ptr); }
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private:
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inline T *_getAndInc() const
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throw()
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{
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if (_ptr)
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++_ptr->__refCount;
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return _ptr;
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}
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T *_ptr;
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};
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} // namespace ZeroTier
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#endif
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