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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 */
/* Owns the frame tree and provides APIs to manipulate it */
#ifndef _nsFrameManager_h_
#define _nsFrameManager_h_
#include "nsDebug.h"
#include "mozilla/Attributes.h"
#include "nsFrameList.h"
class nsContainerFrame;
class nsIFrame;
class nsILayoutHistoryState;
class nsPlaceholderFrame;
class nsWindowSizes;
namespace mozilla {
class PresShell;
} // namespace mozilla
* Frame manager interface. The frame manager owns the frame tree model, and
* handles structural manipulations to it, such as appending and inserting a
* list of frames to a parent frame, or removing a child frame from a parent
* frame.
class nsFrameManager {
typedef mozilla::PresShell PresShell;
typedef mozilla::layout::FrameChildListID ChildListID;
explicit nsFrameManager(PresShell* aPresShell)
: mPresShell(aPresShell), mRootFrame(nullptr) {
MOZ_ASSERT(mPresShell, "need a pres shell");
* 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;
* After Destroy is called, it is an error to call any FrameManager methods.
* Destroy should be called when the frame tree managed by the frame
* manager is no longer being displayed.
void Destroy();
// Functions for manipulating the frame model
void AppendFrames(nsContainerFrame* aParentFrame, ChildListID aListID,
nsFrameList& aFrameList);
void InsertFrames(nsContainerFrame* aParentFrame, ChildListID aListID,
nsIFrame* aPrevFrame, nsFrameList& aFrameList);
void RemoveFrame(ChildListID aListID, nsIFrame* aOldFrame);
* Capture/restore frame state for the frame subtree rooted at aFrame.
* aState is the document state storage object onto which each frame
* stores its state. Callers of CaptureFrameState are responsible for
* traversing next continuations of special siblings of aFrame as
* needed; this method will only work with actual frametree descendants
* of aFrame.
void CaptureFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
void RestoreFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
* Add/restore state for one frame
void CaptureFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
void RestoreFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
// weak link, because the pres shell owns us
PresShell* MOZ_NON_OWNING_REF mPresShell;
nsIFrame* mRootFrame;