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/*
* Copyright (C) 2010 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 WebPrivatePtr_h
#define WebPrivatePtr_h
#include "WebCommon.h"
#if INSIDE_BLINK
#include "wtf/PassRefPtr.h"
#endif
namespace blink {
// This class is an implementation detail of the WebKit API. It exists
// to help simplify the implementation of WebKit interfaces that merely
// wrap a reference counted WebCore class.
//
// A typical implementation of a class which uses WebPrivatePtr might look like
// this:
// class WebFoo {
// public:
// virtual ~WebFoo() { } // Only necessary if WebFoo will be used as a
// // base class.
// WebFoo() { }
// WebFoo(const WebFoo& other) { assign(other); }
// WebFoo& operator=(const WebFoo& other)
// {
// assign(other);
// return *this;
// }
// BLINK_EXPORT void assign(const WebFoo&); // Implemented in the body.
//
// // Methods that are exposed to Chromium and which are specific to
// // WebFoo go here.
// BLINK_EXPORT doWebFooThing();
//
// // Methods that are used only by other WebKit/chromium API classes
// // should only be declared when INSIDE_BLINK is set.
// #if INSIDE_BLINK
// WebFoo(const WTF::PassRefPtr<WebCore::Foo>&);
// #endif
//
// private:
// WebPrivatePtr<WebCore::Foo> m_private;
// };
//
template <typename T>
class WebPrivatePtr {
public:
WebPrivatePtr() : m_ptr(0) { }
~WebPrivatePtr() { BLINK_ASSERT(!m_ptr); }
bool isNull() const { return !m_ptr; }
#if INSIDE_BLINK
WebPrivatePtr(const PassRefPtr<T>& prp)
: m_ptr(prp.leakRef())
{
}
void reset()
{
assign(0);
}
WebPrivatePtr<T>& operator=(const WebPrivatePtr<T>& other)
{
T* p = other.m_ptr;
if (p)
p->ref();
assign(p);
return *this;
}
WebPrivatePtr<T>& operator=(const PassRefPtr<T>& prp)
{
assign(prp.leakRef());
return *this;
}
T* get() const
{
return m_ptr;
}
T* operator->() const
{
ASSERT(m_ptr);
return m_ptr;
}
#endif
private:
#if INSIDE_BLINK
void assign(T* p)
{
// p is already ref'd for us by the caller
if (m_ptr)
m_ptr->deref();
m_ptr = p;
}
#else
// Disable the assignment operator; we define it above for when
// INSIDE_BLINK is set, but we need to make sure that it is not
// used outside there; the compiler-provided version won't handle reference
// counting properly.
WebPrivatePtr<T>& operator=(const WebPrivatePtr<T>& other);
#endif
// Disable the copy constructor; classes that contain a WebPrivatePtr
// should implement their copy constructor using assign().
WebPrivatePtr(const WebPrivatePtr<T>&);
T* m_ptr;
};
} // namespace blink
#endif
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