gecko-dev/layout/base/nsFrameManagerBase.h
Jeff Muizelaar 6d2bb0d368 Bug 764188 - Expose a global frame tree generation number. r=dbaron
This generation number will be incremented every time that the frame
tree for a presshell changes. Callers need to deal with the case where
this value overflows. We use this to avoid a bunch of Android
screenshotting.
2012-07-04 11:42:29 -04:00

82 lines
2.6 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim:cindent:ts=2:et:sw=2:
*
* 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/.
*
* This Original Code has been modified by IBM Corporation. Modifications made
* by IBM described herein are Copyright (c) International Business Machines
* Corporation, 2000. Modifications to Mozilla code or documentation identified
* per MPL Section 3.3
*
* Date Modified by Description of modification
* 04/20/2000 IBM Corp. OS/2 VisualAge build.
*/
/* part of nsFrameManager, to work around header inclusionordering */
#ifndef _nsFrameManagerBase_h_
#define _nsFrameManagerBase_h_
#include "pldhash.h"
class nsIPresShell;
class nsStyleSet;
class nsIContent;
class nsPlaceholderFrame;
class nsIFrame;
class nsStyleContext;
class nsIAtom;
class nsStyleChangeList;
class nsILayoutHistoryState;
class nsFrameManagerBase
{
public:
nsFrameManagerBase()
{
memset(this, '\0', sizeof(nsFrameManagerBase));
}
bool IsDestroyingFrames() { return mIsDestroyingFrames; }
/*
* Gets and sets the root frame (typically the viewport). The lifetime of the
* root frame is controlled by the frame manager. When the frame manager is
* destroyed, it destroys the entire frame hierarchy.
*/
NS_HIDDEN_(nsIFrame*) GetRootFrame() const { return mRootFrame; }
NS_HIDDEN_(void) SetRootFrame(nsIFrame* aRootFrame)
{
NS_ASSERTION(!mRootFrame, "already have a root frame");
mRootFrame = aRootFrame;
}
static PRUint32 GetGlobalGenerationNumber() { return sGlobalGenerationNumber; }
protected:
class UndisplayedMap;
// weak link, because the pres shell owns us
nsIPresShell* mPresShell;
// the pres shell owns the style set
nsStyleSet* mStyleSet;
nsIFrame* mRootFrame;
PLDHashTable mPlaceholderMap;
UndisplayedMap* mUndisplayedMap;
bool mIsDestroyingFrames; // The frame manager is destroying some frame(s).
// The frame tree generation number
// We use this to avoid unnecessary screenshotting
// on Android. Unfortunately, this is static to match
// the single consumer which is also static. Keeping
// this the same greatly simplifies lifetime issues and
// makes sure we always using the correct number.
// A per PresContext generation number is available
// via nsPresContext::GetDOMGeneration
static PRUint32 sGlobalGenerationNumber;
};
#endif