layout/generic/nsIStatefulFrame.h
author Gregory Szorc <gps@mozilla.com>
Wed, 28 Jan 2015 13:37:00 -0800
branchMOBILE140_2012062810_RELBRANCH
changeset 120206 b35ea06c61f7497f88f507c06ae65dea4c9c2544
parent 40660 7d2746bc747110f55a6674d032df402a8d506e0d
child 98529 f4157e8c410708d76703f19e4dfb61859bfe32d8
permissions -rw-r--r--
Close old release branch MOBILE140_2012062810_RELBRANCH

/*
 * 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 */