/*
* Copyright (C) 2014 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef WTF_RawPtr_h
#define WTF_RawPtr_h
#include <algorithm>
#include <stdint.h>
#include "wtf/HashTableDeletedValueType.h"
// RawPtr is a simple wrapper for a raw pointer that provides the
// interface (get, clear) of other pointer types such as RefPtr,
// Persistent and Member. This is used for the Blink garbage
// collection work in order to be able to write shared code that will
// use reference counting or garbage collection based on a
// compile-time flag.
namespace WTF {
template<typename T>
class RawPtr {
WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(RawPtr);
WTF_DISALLOW_ZERO_ASSIGNMENT(RawPtr);
public:
RawPtr()
{
#ifndef NDEBUG
m_ptr = reinterpret_cast<T*>(rawPtrZapValue);
#endif
}
RawPtr(std::nullptr_t) : m_ptr(0) { }
RawPtr(T* ptr) : m_ptr(ptr) { }
explicit RawPtr(T& reference) : m_ptr(&reference) { }
RawPtr(const RawPtr& other)
: m_ptr(other.get())
{
}
template<typename U>
RawPtr(const RawPtr<U>& other)
: m_ptr(other.get())
{
}
// Hash table deleted values, which are only constructed and never copied or destroyed.
RawPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
T* get() const { return m_ptr; }
void clear() { m_ptr = 0; }
// FIXME: oilpan: Remove release and leakRef once we remove RefPtrWillBeRawPtr.
RawPtr<T> release()
{
RawPtr<T> tmp = m_ptr;
m_ptr = 0;
return tmp;
}
T* leakRef()
{
T* ptr = m_ptr;
m_ptr = 0;
return ptr;
}
template<typename U>
RawPtr& operator=(U* ptr)
{
m_ptr = ptr;
return *this;
}
template<typename U>
RawPtr& operator=(RawPtr<U> ptr)
{
m_ptr = ptr.get();
return *this;
}
RawPtr& operator=(std::nullptr_t)
{
m_ptr = 0;
return *this;
}
operator T*() const { return m_ptr; }
T& operator*() const { return *m_ptr; }
T* operator->() const { return m_ptr; }
bool operator!() const { return !m_ptr; }
void swap(RawPtr& o)
{
std::swap(m_ptr, o.m_ptr);
}
static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
private:
static const uintptr_t rawPtrZapValue = 0x3a3a3a3a;
T* m_ptr;
};
template<typename T, typename U> inline RawPtr<T> static_pointer_cast(const RawPtr<U>& p)
{
return RawPtr<T>(static_cast<T*>(p.get()));
}
template<typename T> inline T* getPtr(const RawPtr<T>& p)
{
return p.get();
}
} // namespace WTF
using WTF::RawPtr;
#endif