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

// A frame for CSS multi-column layout that wraps nsColumnSetFrames and
// column-span frames.

#ifndef mozilla_ColumnSetWrapperFrame_h
#define mozilla_ColumnSetWrapperFrame_h

#include "nsBlockFrame.h"

namespace mozilla {

// This class is a wrapper for nsColumnSetFrames and column-span frame.
// Essentially, we divide the *original* nsColumnSetFrame into multiple
// nsColumnSetFrames on the basis of the number and position of spanning
// elements.
//
// This wrapper is necessary for implementing column-span as it allows us to
// maintain each nsColumnSetFrame as an independent set of columns, and each
// column-span element then becomes just a block level element.
//
class ColumnSetWrapperFrame final : public nsBlockFrame
{
public:
  NS_DECL_FRAMEARENA_HELPERS(ColumnSetWrapperFrame)
  NS_DECL_QUERYFRAME

  friend nsBlockFrame* ::NS_NewColumnSetWrapperFrame(nsIPresShell* aPresShell,
                                                     ComputedStyle* aStyle,
                                                     nsFrameState aStateFlags);

#ifdef DEBUG_FRAME_DUMP
  nsresult GetFrameName(nsAString& aResult) const override;
#endif

  void AppendFrames(ChildListID aListID, nsFrameList& aFrameList) override;

  void InsertFrames(ChildListID aListID,
                    nsIFrame* aPrevFrame,
                    nsFrameList& aFrameList) override;

  void RemoveFrame(ChildListID aListID, nsIFrame* aOldFrame) override;

private:
  explicit ColumnSetWrapperFrame(ComputedStyle* aStyle);
  ~ColumnSetWrapperFrame() override = default;
};

} // namespace mozilla

#endif // mozilla_ColumnSetWrapperFrame_h