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99 lines
2.9 KiB
99 lines
2.9 KiB
/* |
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* ZeroTier One - Network Virtualization Everywhere |
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* Copyright (C) 2011-2016 ZeroTier, Inc. https://www.zerotier.com/ |
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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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#ifndef ZT_LOCKINGPTR_HPP |
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#define ZT_LOCKINGPTR_HPP |
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#include "Mutex.hpp" |
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namespace ZeroTier { |
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/** |
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* A simple pointer that locks and holds a mutex until destroyed |
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* |
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* Care must be taken when using this. It's not very sophisticated and does |
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* not handle being copied except for the simple return use case. When it is |
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* copied it hands off the mutex to the copy and clears it in the original, |
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* meaning that the mutex is unlocked when the last LockingPtr<> in a chain |
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* of such handoffs is destroyed. If this chain of handoffs "forks" (more than |
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* one copy is made) then non-determinism may ensue. |
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* |
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* This does not delete or do anything else with the pointer. It also does not |
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* take care of locking the lock. That must be done beforehand. |
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*/ |
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template<typename T> |
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class LockingPtr |
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{ |
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public: |
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LockingPtr() : |
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_ptr((T *)0), |
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_lock((Mutex *)0) |
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{ |
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} |
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LockingPtr(T *obj,Mutex *lock) : |
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_ptr(obj), |
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_lock(lock) |
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{ |
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} |
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LockingPtr(const LockingPtr &p) : |
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_ptr(p._ptr), |
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_lock(p._lock) |
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{ |
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const_cast<LockingPtr *>(&p)->_lock = (Mutex *)0; |
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} |
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~LockingPtr() |
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{ |
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if (_lock) |
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_lock->unlock(); |
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} |
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inline LockingPtr &operator=(const LockingPtr &p) |
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{ |
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_ptr = p._ptr; |
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_lock = p._lock; |
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const_cast<LockingPtr *>(&p)->_lock = (Mutex *)0; |
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return *this; |
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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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inline bool operator==(const LockingPtr &sp) const throw() { return (_ptr == sp._ptr); } |
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inline bool operator!=(const LockingPtr &sp) const throw() { return (_ptr != sp._ptr); } |
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inline bool operator>(const LockingPtr &sp) const throw() { return (_ptr > sp._ptr); } |
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inline bool operator<(const LockingPtr &sp) const throw() { return (_ptr < sp._ptr); } |
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inline bool operator>=(const LockingPtr &sp) const throw() { return (_ptr >= sp._ptr); } |
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inline bool operator<=(const LockingPtr &sp) const throw() { return (_ptr <= sp._ptr); } |
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private: |
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T *_ptr; |
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Mutex *_lock; |
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}; |
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} // namespace ZeroTier |
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#endif
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