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Diffstat (limited to 'attic')
-rw-r--r-- | attic/LockingPtr.hpp | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/attic/LockingPtr.hpp b/attic/LockingPtr.hpp new file mode 100644 index 00000000..c373129a --- /dev/null +++ b/attic/LockingPtr.hpp @@ -0,0 +1,99 @@ +/* + * ZeroTier One - Network Virtualization Everywhere + * Copyright (C) 2011-2016 ZeroTier, Inc. https://www.zerotier.com/ + * + * This program 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 of the License, or + * (at your option) any later version. + * + * This program 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 program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef ZT_LOCKINGPTR_HPP +#define ZT_LOCKINGPTR_HPP + +#include "Mutex.hpp" + +namespace ZeroTier { + +/** + * A simple pointer that locks and holds a mutex until destroyed + * + * Care must be taken when using this. It's not very sophisticated and does + * not handle being copied except for the simple return use case. When it is + * copied it hands off the mutex to the copy and clears it in the original, + * meaning that the mutex is unlocked when the last LockingPtr<> in a chain + * of such handoffs is destroyed. If this chain of handoffs "forks" (more than + * one copy is made) then non-determinism may ensue. + * + * This does not delete or do anything else with the pointer. It also does not + * take care of locking the lock. That must be done beforehand. + */ +template<typename T> +class LockingPtr +{ +public: + LockingPtr() : + _ptr((T *)0), + _lock((Mutex *)0) + { + } + + LockingPtr(T *obj,Mutex *lock) : + _ptr(obj), + _lock(lock) + { + } + + LockingPtr(const LockingPtr &p) : + _ptr(p._ptr), + _lock(p._lock) + { + const_cast<LockingPtr *>(&p)->_lock = (Mutex *)0; + } + + ~LockingPtr() + { + if (_lock) + _lock->unlock(); + } + + inline LockingPtr &operator=(const LockingPtr &p) + { + _ptr = p._ptr; + _lock = p._lock; + const_cast<LockingPtr *>(&p)->_lock = (Mutex *)0; + return *this; + } + + inline operator bool() const throw() { return (_ptr != (T *)0); } + inline T &operator*() const throw() { return *_ptr; } + inline T *operator->() const throw() { return _ptr; } + + /** + * @return Raw pointer to held object + */ + inline T *ptr() const throw() { return _ptr; } + + inline bool operator==(const LockingPtr &sp) const throw() { return (_ptr == sp._ptr); } + inline bool operator!=(const LockingPtr &sp) const throw() { return (_ptr != sp._ptr); } + inline bool operator>(const LockingPtr &sp) const throw() { return (_ptr > sp._ptr); } + inline bool operator<(const LockingPtr &sp) const throw() { return (_ptr < sp._ptr); } + inline bool operator>=(const LockingPtr &sp) const throw() { return (_ptr >= sp._ptr); } + inline bool operator<=(const LockingPtr &sp) const throw() { return (_ptr <= sp._ptr); } + +private: + T *_ptr; + Mutex *_lock; +}; + +} // namespace ZeroTier + +#endif |