third_party/WebKit/Source/core/editing/LayoutSelection.h

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2006 Apple Computer, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef LayoutSelection_h
#define LayoutSelection_h

#include "core/editing/Position.h"
#include "core/editing/VisibleSelection.h"
#include "platform/heap/Handle.h"

namespace blink {

class FrameSelection;

// This class represents a selection range in layout tree for painting and
// paint invalidation.
// The current selection to be painted is represented as 2 pairs of
// (LayoutObject, offset).
// 2 LayoutObjects are only valid for |Text| node without 'transform' or
// 'first-letter'.
// TODO(editing-dev): Clarify the meaning of "offset".
// editing/ passes them as offsets in the DOM tree but layout uses them as
// offset in the layout tree. This doesn't work in the cases of
// CSS first-letter or character transform. See crbug.com/17528.
class SelectionPaintRange {
  DISALLOW_NEW();

 public:
  SelectionPaintRange() = default;
  SelectionPaintRange(LayoutObject* start_layout_object,
                      int start_offset,
                      LayoutObject* end_layout_object,
                      int end_offset);

  bool operator==(const SelectionPaintRange& other) const;

  LayoutObject* StartLayoutObject() const;
  int StartOffset() const;
  LayoutObject* EndLayoutObject() const;
  int EndOffset() const;

  bool IsNull() const { return !start_layout_object_; }

 private:
  LayoutObject* start_layout_object_ = nullptr;
  int start_offset_ = -1;
  LayoutObject* end_layout_object_ = nullptr;
  int end_offset_ = -1;
};

class LayoutSelection final : public GarbageCollected<LayoutSelection> {
 public:
  static LayoutSelection* Create(FrameSelection& frame_selection) {
    return new LayoutSelection(frame_selection);
  }

  bool HasPendingSelection() const { return has_pending_selection_; }
  void SetHasPendingSelection() { has_pending_selection_ = true; }
  void Commit();

  IntRect SelectionBounds();
  void InvalidatePaintForSelection();
  enum SelectionPaintInvalidationMode {
    kPaintInvalidationNewXOROld,
    kPaintInvalidationNewMinusOld
  };
  void SetSelection(
      const SelectionPaintRange&,
      SelectionPaintInvalidationMode = kPaintInvalidationNewXOROld);
  void ClearSelection();
  std::pair<int, int> SelectionStartEnd();
  void OnDocumentShutdown();

  DECLARE_TRACE();

 private:
  LayoutSelection(FrameSelection&);

  SelectionInFlatTree CalcVisibleSelection(
      const VisibleSelectionInFlatTree&) const;

  Member<FrameSelection> frame_selection_;
  bool has_pending_selection_ : 1;

  SelectionPaintRange paint_range_;
};

}  // namespace blink

#endif