/* -*- 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/. */

/*

 * rendering object that is the root of the frame tree, which contains

 * the document's scrollbars and contains fixed-positioned elements

 */

#ifndef mozilla_ViewportFrame_h

#define mozilla_ViewportFrame_h

#include "mozilla/Attributes.h"

#include "nsContainerFrame.h"

class nsPresContext;

namespace mozilla {

class ServoRestyleState;

/**

  * ViewportFrame is the parent of a single child - the doc root frame or a scroll frame

  * containing the doc root frame. ViewportFrame stores this child in its primary child

  * list.

  */

class ViewportFrame : public nsContainerFrame

{

public:

  NS_DECL_QUERYFRAME

  NS_DECL_FRAMEARENA_HELPERS(ViewportFrame)

  explicit ViewportFrame(ComputedStyle* aStyle)

    : ViewportFrame(aStyle, kClassID)

  {}

  virtual ~ViewportFrame() { } // useful for debugging

  virtual void Init(nsIContent*       aContent,

                    nsContainerFrame* aParent,

                    nsIFrame*         aPrevInFlow) override;

#ifdef DEBUG

  virtual void AppendFrames(ChildListID     aListID,

                            nsFrameList&    aFrameList) override;

  virtual void InsertFrames(ChildListID     aListID,

                            nsIFrame*       aPrevFrame,

                            nsFrameList&    aFrameList) override;

  virtual void RemoveFrame(ChildListID     aListID,

                           nsIFrame*       aOldFrame) override;

#endif

  virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,

                                const nsDisplayListSet& aLists) override;

  void BuildDisplayListForTopLayer(nsDisplayListBuilder* aBuilder,

                                   nsDisplayList* aList);

  virtual nscoord GetMinISize(gfxContext *aRenderingContext) override;

  virtual nscoord GetPrefISize(gfxContext *aRenderingContext) override;

  virtual void Reflow(nsPresContext* aPresContext,

                      ReflowOutput& aDesiredSize,

                      const ReflowInput& aReflowInput,

                      nsReflowStatus& aStatus) override;

  virtual bool ComputeCustomOverflow(nsOverflowAreas& aOverflowAreas) override;

  /**

   * Adjust aReflowInput to account for scrollbars and pres shell

   * GetVisualViewportSizeSet and

   * GetContentDocumentFixedPositionMargins adjustments.

   * @return the rect to use as containing block rect

   */

  nsRect AdjustReflowInputAsContainingBlock(ReflowInput* aReflowInput) const;

  /**

   * Update our style (and recursively the styles of any anonymous boxes we

   * might own)

   */

  void UpdateStyle(ServoRestyleState& aStyleSet);

  /**

   * Return our single anonymous box child.

   */

  void AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult) override;

#ifdef DEBUG_FRAME_DUMP

  virtual nsresult GetFrameName(nsAString& aResult) const override;

#endif

protected:

  ViewportFrame(ComputedStyle* aStyle, ClassID aID)

    : nsContainerFrame(aStyle, aID)

    , mView(nullptr)

  {}

  /**

   * Calculate how much room is available for fixed frames. That means

   * determining if the viewport is scrollable and whether the vertical and/or

   * horizontal scrollbars are visible.  Adjust the computed width/height and

   * available width for aReflowInput accordingly.

   * @return the current scroll position, or 0,0 if not scrollable

   */

  nsPoint AdjustReflowInputForScrollbars(ReflowInput* aReflowInput) const;

  nsView* GetViewInternal() const override { return mView; }

  void SetViewInternal(nsView* aView) override { mView = aView; }

private:

  virtual mozilla::layout::FrameChildListID GetAbsoluteListID() const override { return kFixedList; }

  nsView* mView;

};

} // namespace mozilla

#endif // mozilla_ViewportFrame_h