/indra/llcommon/llsafehandle.h
https://bitbucket.org/lindenlab/viewer-beta/ · C++ Header · 162 lines · 105 code · 22 blank · 35 comment · 15 complexity · e6764e641a721797257134582db6a696 MD5 · raw file
- /**
- * @file llsafehandle.h
- * @brief Reference-counted object where Object() is valid, not NULL.
- *
- * $LicenseInfo:firstyear=2002&license=viewerlgpl$
- * Second Life Viewer Source Code
- * Copyright (C) 2010, Linden Research, Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation;
- * version 2.1 of the License only.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
- * $/LicenseInfo$
- */
- #ifndef LLSAFEHANDLE_H
- #define LLSAFEHANDLE_H
- #include "llerror.h" // *TODO: consider eliminating this
- // Expands LLPointer to return a pointer to a special instance of class Type instead of NULL.
- // This is useful in instances where operations on NULL pointers are semantically safe and/or
- // when error checking occurs at a different granularity or in a different part of the code
- // than when referencing an object via a LLSafeHandle.
- template <class Type>
- class LLSafeHandle
- {
- public:
- LLSafeHandle() :
- mPointer(NULL)
- {
- }
- LLSafeHandle(Type* ptr) :
- mPointer(NULL)
- {
- assign(ptr);
- }
- LLSafeHandle(const LLSafeHandle<Type>& ptr) :
- mPointer(NULL)
- {
- assign(ptr.mPointer);
- }
- // support conversion up the type hierarchy. See Item 45 in Effective C++, 3rd Ed.
- template<typename Subclass>
- LLSafeHandle(const LLSafeHandle<Subclass>& ptr) :
- mPointer(NULL)
- {
- assign(ptr.get());
- }
- ~LLSafeHandle()
- {
- unref();
- }
- const Type* operator->() const { return nonNull(mPointer); }
- Type* operator->() { return nonNull(mPointer); }
- Type* get() const { return mPointer; }
- void clear() { assign(NULL); }
- // we disallow these operations as they expose our null objects to direct manipulation
- // and bypass the reference counting semantics
- //const Type& operator*() const { return *nonNull(mPointer); }
- //Type& operator*() { return *nonNull(mPointer); }
- operator BOOL() const { return mPointer != NULL; }
- operator bool() const { return mPointer != NULL; }
- bool operator!() const { return mPointer == NULL; }
- bool isNull() const { return mPointer == NULL; }
- bool notNull() const { return mPointer != NULL; }
- operator Type*() const { return mPointer; }
- operator const Type*() const { return mPointer; }
- bool operator !=(Type* ptr) const { return (mPointer != ptr); }
- bool operator ==(Type* ptr) const { return (mPointer == ptr); }
- bool operator ==(const LLSafeHandle<Type>& ptr) const { return (mPointer == ptr.mPointer); }
- bool operator < (const LLSafeHandle<Type>& ptr) const { return (mPointer < ptr.mPointer); }
- bool operator > (const LLSafeHandle<Type>& ptr) const { return (mPointer > ptr.mPointer); }
- LLSafeHandle<Type>& operator =(Type* ptr)
- {
- assign(ptr);
- return *this;
- }
- LLSafeHandle<Type>& operator =(const LLSafeHandle<Type>& ptr)
- {
- assign(ptr.mPointer);
- return *this;
- }
- // support assignment up the type hierarchy. See Item 45 in Effective C++, 3rd Ed.
- template<typename Subclass>
- LLSafeHandle<Type>& operator =(const LLSafeHandle<Subclass>& ptr)
- {
- assign(ptr.get());
- return *this;
- }
- public:
- typedef Type* (*NullFunc)();
- static const NullFunc sNullFunc;
- protected:
- void ref()
- {
- if (mPointer)
- {
- mPointer->ref();
- }
- }
- void unref()
- {
- if (mPointer)
- {
- Type *tempp = mPointer;
- mPointer = NULL;
- tempp->unref();
- if (mPointer != NULL)
- {
- llwarns << "Unreference did assignment to non-NULL because of destructor" << llendl;
- unref();
- }
- }
- }
- void assign(Type* ptr)
- {
- if( mPointer != ptr )
- {
- unref();
- mPointer = ptr;
- ref();
- }
- }
- static Type* nonNull(Type* ptr)
- {
- return ptr == NULL ? sNullFunc() : ptr;
- }
- protected:
- Type* mPointer;
- };
- #endif