gecko-dev/layout/base/nsFrameManagerBase.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim:cindent:ts=2:et:sw=2:
*
2012-05-21 11:12:37 +00:00
* 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 "nsDebug.h"
#include "pldhash.h"
class nsIFrame;
class nsIPresShell;
class nsStyleSet;
class nsFrameManagerBase
{
public:
nsFrameManagerBase()
: mPresShell(nullptr)
, mStyleSet(nullptr)
, mRootFrame(nullptr)
, mUndisplayedMap(nullptr)
, mDisplayContentsMap(nullptr)
, mIsDestroyingFrames(false)
{
}
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.
*/
nsIFrame* GetRootFrame() const { return mRootFrame; }
void SetRootFrame(nsIFrame* aRootFrame)
{
NS_ASSERTION(!mRootFrame, "already have a root frame");
mRootFrame = aRootFrame;
}
static uint32_t 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;
UndisplayedMap* mDisplayContentsMap;
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 uint32_t sGlobalGenerationNumber;
};
#endif