New git repository for release - version 0.2.0 tagged

node/SharedPtr.hpp

@@ -0,0 +1,133 @@
+/*
+ * ZeroTier One - Global Peer to Peer Ethernet
+ * Copyright (C) 2012-2013  ZeroTier Networks LLC
+ *
+ * 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/>.
+ *
+ * --
+ *
+ * ZeroTier may be used and distributed under the terms of the GPLv3, which
+ * are available at: http://www.gnu.org/licenses/gpl-3.0.html
+ *
+ * If you would like to embed ZeroTier into a commercial application or
+ * redistribute it in a modified binary form, please contact ZeroTier Networks
+ * LLC. Start here: http://www.zerotier.com/
+ */
+
+#ifndef _ZT_SHAREDPTR_HPP
+#define _ZT_SHAREDPTR_HPP
+
+#include "Mutex.hpp"
+#include "AtomicCounter.hpp"
+
+namespace ZeroTier {
+
+/**
+ * Simple reference counted pointer
+ *
+ * This is an introspective shared pointer. Classes that need to be reference
+ * counted must list this as a 'friend' and must have a private instance of
+ * AtomicCounter called __refCount. They should also have private destructors,
+ * since only this class should delete them.
+ *
+ * Because this is introspective, it is safe to apply to a naked pointer
+ * multiple times provided there is always at least one holding SharedPtr.
+ */
+template<typename T>
+class SharedPtr
+{
+public:
+	SharedPtr()
+		throw() :
+		_ptr((T *)0)
+	{
+	}
+
+	SharedPtr(T *obj)
+		throw() :
+		_ptr(obj)
+	{
+		++obj->__refCount;
+	}
+
+	SharedPtr(const SharedPtr &sp)
+		throw() :
+		_ptr(sp._getAndInc())
+	{
+	}
+
+	~SharedPtr()
+	{
+		if (_ptr) {
+			if (--_ptr->__refCount <= 0)
+				delete _ptr;
+		}
+	}
+
+	inline SharedPtr &operator=(const SharedPtr &sp)
+	{
+		if (_ptr != sp._ptr) {
+			T *p = sp._getAndInc();
+			if (_ptr) {
+				if (--_ptr->__refCount <= 0)
+					delete _ptr;
+			}
+			_ptr = p;
+		}
+		return *this;
+	}
+
+	inline operator bool() const throw() { return (_ptr); }
+	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; }
+
+	/**
+	 * Set this pointer to null
+	 */
+	inline void zero()
+	{
+		if (_ptr) {
+			if (--_ptr->__refCount <= 0)
+				delete _ptr;
+		}
+		_ptr = (T *)0;
+	}
+
+	inline bool operator==(const SharedPtr &sp) const throw() { return (_ptr == sp._ptr); }
+	inline bool operator!=(const SharedPtr &sp) const throw() { return (_ptr != sp._ptr); }
+	inline bool operator>(const SharedPtr &sp) const throw() { return (_ptr > sp._ptr); }
+	inline bool operator<(const SharedPtr &sp) const throw() { return (_ptr < sp._ptr); }
+	inline bool operator>=(const SharedPtr &sp) const throw() { return (_ptr >= sp._ptr); }
+	inline bool operator<=(const SharedPtr &sp) const throw() { return (_ptr <= sp._ptr); }
+
+private:
+	inline T *_getAndInc() const
+		throw()
+	{
+		if (_ptr)
+			++_ptr->__refCount;
+		return _ptr;
+	}
+
+	T *_ptr;
+};
+
+} // namespace ZeroTier
+
+#endif