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/*
* Copyright (C) 2008 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 COMPUTER, INC. ``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 COMPUTER, INC. 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 ContextLifecycleObserver_h
#define ContextLifecycleObserver_h
#include "core/CoreExport.h"
#include "core/dom/ExecutionContext.h"
#include "platform/LifecycleObserver.h"
namespace blink {
class LocalDOMWindow;
class LocalFrame;
// ContextClient and ContextLifecycleObserver are helpers to associate an
// object with an ExecutionContext.
//
// - getExecutionContext() returns null after the context is detached.
// - frame() is a syntax sugar for getExecutionContext()->frame(). It returns
// null after the context is detached or the context is not a Document.
class CORE_EXPORT ContextClient : public GarbageCollectedMixin {
public:
ExecutionContext* getExecutionContext() const;
LocalFrame* frame() const;
DECLARE_VIRTUAL_TRACE();
protected:
explicit ContextClient(ExecutionContext*);
explicit ContextClient(LocalFrame*);
private:
WeakMember<ExecutionContext> m_executionContext;
};
// ContextLifecycleObserver provides an additional contextDestroyed() hook
// to execute cleanup code when a context is destroyed. Prefer the simpler
// ContextClient when possible.
class CORE_EXPORT ContextLifecycleObserver
: public LifecycleObserver<ExecutionContext, ContextLifecycleObserver> {
public:
virtual void contextDestroyed(ExecutionContext*) {}
ExecutionContext* getExecutionContext() const { return lifecycleContext(); }
LocalFrame* frame() const;
enum Type {
GenericType,
SuspendableObjectType,
};
Type observerType() const { return m_observerType; }
protected:
explicit ContextLifecycleObserver(ExecutionContext* executionContext,
Type type = GenericType)
: LifecycleObserver(executionContext), m_observerType(type) {}
private:
Type m_observerType;
};
// DOMWindowClient is a helper to associate an object with a LocalDOMWindow.
//
// - domWindow() returns null after the window is detached.
// - frame() is a syntax sugar for domWindow()->frame(). It returns
// null after the window is detached.
//
// If the object is a per-ExecutionContext thing, use ContextClient/
// ContextLifecycleObserver. If the object is a per-DOMWindow thing, use
// DOMWindowClient. Basically, DOMWindowClient is expected to be used (only)
// for objects directly held by LocalDOMWindow. Other objects should use
// ContextClient/ContextLifecycleObserver.
//
// There is a subtle difference between the timing when the context gets
// detached and the timing when the window gets detached. In common cases,
// these two happen at the same timing. The only exception is a case where
// a frame navigates from an initial empty document to another same-origin
// document. In this case, a Document is recreated but a DOMWindow is reused.
// Hence, in the navigated document ContextClient::getExecutionContext()
// returns null while DOMWindowClient::domWindow() keeps returning the window.
class CORE_EXPORT DOMWindowClient : public GarbageCollectedMixin {
public:
LocalDOMWindow* domWindow() const;
LocalFrame* frame() const;
DECLARE_VIRTUAL_TRACE();
protected:
explicit DOMWindowClient(LocalDOMWindow*);
explicit DOMWindowClient(LocalFrame*);
private:
WeakMember<LocalDOMWindow> m_domWindow;
};
} // namespace blink
#endif // ContextLifecycleObserver_h
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