gecko-dev/layout/generic/nsIStatefulFrame.h

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* interface for rendering objects whose state is saved in
* session-history (back-forward navigation)
*/
#ifndef _nsIStatefulFrame_h
#define _nsIStatefulFrame_h
#include "nsQueryFrame.h"
class nsPresState;
class nsIStatefulFrame
{
public:
NS_DECL_QUERYFRAME_TARGET(nsIStatefulFrame)
// If you create a special type stateful frame (e.g. scroll) that needs
// to be captured outside of the standard pass through the frames, you'll need
// a special ID by which to refer to that type.
enum SpecialStateID {eNoID=0, eDocumentScrollState};
// Save the state for this frame. Some implementations may choose to return
// different states depending on the value of aStateID. If this method
// succeeds, the caller is responsible for deleting the resulting state when
// done with it.
NS_IMETHOD SaveState(SpecialStateID aStateID, nsPresState** aState) = 0;
// Restore the state for this frame from aState
NS_IMETHOD RestoreState(nsPresState* aState) = 0;
};
#endif /* _nsIStatefulFrame_h */