/* -*- 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 http://mozilla.org/MPL/2.0/. */

/* storage of the frame tree and information about it */

#ifndef _nsFrameManager_h_

#define _nsFrameManager_h_

#include "nsDebug.h"

#include "mozilla/Attributes.h"

#include "nsFrameList.h"

class nsContainerFrame;

class nsIFrame;

class nsILayoutHistoryState;

class nsIPresShell;

class nsPlaceholderFrame;

class nsWindowSizes;

/**

 * Frame manager interface. The frame manager serves one purpose:

 * <li>handles structural modifications to the frame model. If the frame model

 * lock can be acquired, then the changes are processed immediately; otherwise,

 * they're queued and processed later.

 *

 * FIXME(emilio): The comment above doesn't make any sense, there's no "frame

 * model lock" of any sort afaict.

 */

class nsFrameManager

{

  typedef mozilla::layout::FrameChildListID ChildListID;

public:

  explicit nsFrameManager(nsIPresShell* aPresShell)

    : mPresShell(aPresShell)

    , mRootFrame(nullptr)

  {

    MOZ_ASSERT(mPresShell, "need a pres shell");

  }

  ~nsFrameManager();

  /*

   * 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;

protected:

  // weak link, because the pres shell owns us

  nsIPresShell* MOZ_NON_OWNING_REF mPresShell;

  nsIFrame* mRootFrame;

};

#endif