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/*
* Copyright (C) 2013 Apple 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:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 RenderPtr_h
#define RenderPtr_h
#include <algorithm>
#include <cstddef>
#include <memory>
#include <wtf/Assertions.h>
#include <wtf/HashTraits.h>
namespace WebCore {
template<typename T> class RenderPtr {
public:
typedef T ValueType;
typedef ValueType* PtrType;
RenderPtr() : m_ptr(nullptr) { }
RenderPtr(std::nullptr_t) : m_ptr(nullptr) { }
explicit RenderPtr(T* ptr) : m_ptr(ptr) { }
~RenderPtr()
{
if (m_ptr)
m_ptr->destroy();
}
PtrType get() const { return m_ptr; }
void clear();
PtrType leakPtr() WARN_UNUSED_RETURN;
ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
bool operator!() const { return !m_ptr; }
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef PtrType RenderPtr::*UnspecifiedBoolType;
operator UnspecifiedBoolType() const { return m_ptr ? &RenderPtr::m_ptr : nullptr; }
RenderPtr& operator=(std::nullptr_t) { clear(); return *this; }
RenderPtr(RenderPtr&&);
template<typename U> RenderPtr(RenderPtr<U>&&);
RenderPtr& operator=(RenderPtr&&);
template<typename U> RenderPtr& operator=(RenderPtr<U>&&);
void swap(RenderPtr& o) { std::swap(m_ptr, o.m_ptr); }
private:
// We should never have two RenderPtrs for the same underlying object (otherwise we'll get
// double-destruction), so these equality operators should never be needed.
template<typename U> bool operator==(const RenderPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), RenderPtrs_should_never_be_equal); return false; }
template<typename U> bool operator!=(const RenderPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), RenderPtrs_should_never_be_equal); return false; }
PtrType m_ptr;
};
template<typename T> inline void RenderPtr<T>::clear()
{
if (m_ptr)
m_ptr->destroy();
m_ptr = nullptr;
}
template<typename T> inline typename RenderPtr<T>::PtrType RenderPtr<T>::leakPtr()
{
PtrType ptr = m_ptr;
m_ptr = nullptr;
return ptr;
}
template<typename T> inline RenderPtr<T>::RenderPtr(RenderPtr<T>&& o)
: m_ptr(o.leakPtr())
{
}
template<typename T> template<typename U> inline RenderPtr<T>::RenderPtr(RenderPtr<U>&& o)
: m_ptr(o.leakPtr())
{
}
template<typename T> inline auto RenderPtr<T>::operator=(RenderPtr&& o) -> RenderPtr&
{
ASSERT(!o || o != m_ptr);
RenderPtr ptr = WTFMove(o);
swap(ptr);
return *this;
}
template<typename T> template<typename U> inline auto RenderPtr<T>::operator=(RenderPtr<U>&& o) -> RenderPtr&
{
ASSERT(!o || o != m_ptr);
RenderPtr ptr = WTFMove(o);
swap(ptr);
return *this;
}
template<typename T> inline void swap(RenderPtr<T>& a, RenderPtr<T>& b)
{
a.swap(b);
}
template<typename T, typename U> inline bool operator==(const RenderPtr<T>& a, U* b)
{
return a.get() == b;
}
template<typename T, typename U> inline bool operator==(T* a, const RenderPtr<U>& b)
{
return a == b.get();
}
template<typename T, typename U> inline bool operator!=(const RenderPtr<T>& a, U* b)
{
return a.get() != b;
}
template<typename T, typename U> inline bool operator!=(T* a, const RenderPtr<U>& b)
{
return a != b.get();
}
template<typename T> inline typename RenderPtr<T>::PtrType getPtr(const RenderPtr<T>& p)
{
return p.get();
}
template<class T, class... Args> inline RenderPtr<T>
createRenderer(Args&&... args)
{
return RenderPtr<T>(new T(std::forward<Args>(args)...));
}
template<typename T, typename U> inline RenderPtr<T> static_pointer_cast(RenderPtr<U>&& p)
{
return RenderPtr<T>(static_cast<T*>(p.leakPtr()));
}
} // namespace WebCore
namespace WTF {
template<typename T> struct HashTraits<WebCore::RenderPtr<T>> : SimpleClassHashTraits<WebCore::RenderPtr<T>> {
typedef std::nullptr_t EmptyValueType;
static EmptyValueType emptyValue() { return nullptr; }
typedef T* PeekType;
static T* peek(const WebCore::RenderPtr<T>& value) { return value.get(); }
static T* peek(std::nullptr_t) { return nullptr; }
};
} // namespace WTF
#endif // RenderPtr_h
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