third_party/WebKit/Source/core/editing/RenderedPosition.cpp

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 */

#include "core/editing/RenderedPosition.h"

#include "core/editing/TextAffinity.h"
#include "core/editing/VisiblePosition.h"
#include "core/editing/VisibleUnits.h"
#include "core/layout/api/LineLayoutAPIShim.h"
#include "core/layout/compositing/CompositedSelectionBound.h"
#include "core/paint/PaintLayer.h"

namespace blink {

template <typename Strategy>
static inline LayoutObject* layoutObjectFromPosition(
    const PositionTemplate<Strategy>& position) {
  DCHECK(position.isNotNull());
  Node* layoutObjectNode = nullptr;
  switch (position.anchorType()) {
    case PositionAnchorType::OffsetInAnchor:
      layoutObjectNode = position.computeNodeAfterPosition();
      if (!layoutObjectNode || !layoutObjectNode->layoutObject())
        layoutObjectNode = position.anchorNode()->lastChild();
      break;

    case PositionAnchorType::BeforeAnchor:
    case PositionAnchorType::AfterAnchor:
      break;

    case PositionAnchorType::BeforeChildren:
      layoutObjectNode = Strategy::firstChild(*position.anchorNode());
      break;
    case PositionAnchorType::AfterChildren:
      layoutObjectNode = Strategy::lastChild(*position.anchorNode());
      break;
  }
  if (!layoutObjectNode || !layoutObjectNode->layoutObject())
    layoutObjectNode = position.anchorNode();
  return layoutObjectNode->layoutObject();
}

RenderedPosition::RenderedPosition(const VisiblePosition& position)
    : RenderedPosition(position.deepEquivalent(), position.affinity()) {}

RenderedPosition::RenderedPosition(const VisiblePositionInFlatTree& position)
    : RenderedPosition(position.deepEquivalent(), position.affinity()) {}

RenderedPosition::RenderedPosition(const Position& position,
                                   TextAffinity affinity)
    : m_layoutObject(nullptr),
      m_inlineBox(nullptr),
      m_offset(0),
      m_prevLeafChild(uncachedInlineBox()),
      m_nextLeafChild(uncachedInlineBox()) {
  if (position.isNull())
    return;
  InlineBoxPosition boxPosition = computeInlineBoxPosition(position, affinity);
  m_inlineBox = boxPosition.inlineBox;
  m_offset = boxPosition.offsetInBox;
  if (m_inlineBox)
    m_layoutObject =
        LineLayoutAPIShim::layoutObjectFrom(m_inlineBox->getLineLayoutItem());
  else
    m_layoutObject = layoutObjectFromPosition(position);
}

RenderedPosition::RenderedPosition(const PositionInFlatTree& position,
                                   TextAffinity affinity)
    : m_layoutObject(nullptr),
      m_inlineBox(nullptr),
      m_offset(0),
      m_prevLeafChild(uncachedInlineBox()),
      m_nextLeafChild(uncachedInlineBox()) {
  if (position.isNull())
    return;
  InlineBoxPosition boxPosition = computeInlineBoxPosition(position, affinity);
  m_inlineBox = boxPosition.inlineBox;
  m_offset = boxPosition.offsetInBox;
  if (m_inlineBox)
    m_layoutObject =
        LineLayoutAPIShim::layoutObjectFrom(m_inlineBox->getLineLayoutItem());
  else
    m_layoutObject = layoutObjectFromPosition(position);
}

InlineBox* RenderedPosition::prevLeafChild() const {
  if (m_prevLeafChild == uncachedInlineBox())
    m_prevLeafChild = m_inlineBox->prevLeafChildIgnoringLineBreak();
  return m_prevLeafChild;
}

InlineBox* RenderedPosition::nextLeafChild() const {
  if (m_nextLeafChild == uncachedInlineBox())
    m_nextLeafChild = m_inlineBox->nextLeafChildIgnoringLineBreak();
  return m_nextLeafChild;
}

bool RenderedPosition::isEquivalent(const RenderedPosition& other) const {
  return (m_layoutObject == other.m_layoutObject &&
          m_inlineBox == other.m_inlineBox && m_offset == other.m_offset) ||
         (atLeftmostOffsetInBox() && other.atRightmostOffsetInBox() &&
          prevLeafChild() == other.m_inlineBox) ||
         (atRightmostOffsetInBox() && other.atLeftmostOffsetInBox() &&
          nextLeafChild() == other.m_inlineBox);
}

unsigned char RenderedPosition::bidiLevelOnLeft() const {
  InlineBox* box = atLeftmostOffsetInBox() ? prevLeafChild() : m_inlineBox;
  return box ? box->bidiLevel() : 0;
}

unsigned char RenderedPosition::bidiLevelOnRight() const {
  InlineBox* box = atRightmostOffsetInBox() ? nextLeafChild() : m_inlineBox;
  return box ? box->bidiLevel() : 0;
}

RenderedPosition RenderedPosition::leftBoundaryOfBidiRun(
    unsigned char bidiLevelOfRun) {
  if (!m_inlineBox || bidiLevelOfRun > m_inlineBox->bidiLevel())
    return RenderedPosition();

  InlineBox* box = m_inlineBox;
  do {
    InlineBox* prev = box->prevLeafChildIgnoringLineBreak();
    if (!prev || prev->bidiLevel() < bidiLevelOfRun)
      return RenderedPosition(
          LineLayoutAPIShim::layoutObjectFrom(box->getLineLayoutItem()), box,
          box->caretLeftmostOffset());
    box = prev;
  } while (box);

  NOTREACHED();
  return RenderedPosition();
}

RenderedPosition RenderedPosition::rightBoundaryOfBidiRun(
    unsigned char bidiLevelOfRun) {
  if (!m_inlineBox || bidiLevelOfRun > m_inlineBox->bidiLevel())
    return RenderedPosition();

  InlineBox* box = m_inlineBox;
  do {
    InlineBox* next = box->nextLeafChildIgnoringLineBreak();
    if (!next || next->bidiLevel() < bidiLevelOfRun)
      return RenderedPosition(
          LineLayoutAPIShim::layoutObjectFrom(box->getLineLayoutItem()), box,
          box->caretRightmostOffset());
    box = next;
  } while (box);

  NOTREACHED();
  return RenderedPosition();
}

bool RenderedPosition::atLeftBoundaryOfBidiRun(
    ShouldMatchBidiLevel shouldMatchBidiLevel,
    unsigned char bidiLevelOfRun) const {
  if (!m_inlineBox)
    return false;

  if (atLeftmostOffsetInBox()) {
    if (shouldMatchBidiLevel == IgnoreBidiLevel)
      return !prevLeafChild() ||
             prevLeafChild()->bidiLevel() < m_inlineBox->bidiLevel();
    return m_inlineBox->bidiLevel() >= bidiLevelOfRun &&
           (!prevLeafChild() || prevLeafChild()->bidiLevel() < bidiLevelOfRun);
  }

  if (atRightmostOffsetInBox()) {
    if (shouldMatchBidiLevel == IgnoreBidiLevel)
      return nextLeafChild() &&
             m_inlineBox->bidiLevel() < nextLeafChild()->bidiLevel();
    return nextLeafChild() && m_inlineBox->bidiLevel() < bidiLevelOfRun &&
           nextLeafChild()->bidiLevel() >= bidiLevelOfRun;
  }

  return false;
}

bool RenderedPosition::atRightBoundaryOfBidiRun(
    ShouldMatchBidiLevel shouldMatchBidiLevel,
    unsigned char bidiLevelOfRun) const {
  if (!m_inlineBox)
    return false;

  if (atRightmostOffsetInBox()) {
    if (shouldMatchBidiLevel == IgnoreBidiLevel)
      return !nextLeafChild() ||
             nextLeafChild()->bidiLevel() < m_inlineBox->bidiLevel();
    return m_inlineBox->bidiLevel() >= bidiLevelOfRun &&
           (!nextLeafChild() || nextLeafChild()->bidiLevel() < bidiLevelOfRun);
  }

  if (atLeftmostOffsetInBox()) {
    if (shouldMatchBidiLevel == IgnoreBidiLevel)
      return prevLeafChild() &&
             m_inlineBox->bidiLevel() < prevLeafChild()->bidiLevel();
    return prevLeafChild() && m_inlineBox->bidiLevel() < bidiLevelOfRun &&
           prevLeafChild()->bidiLevel() >= bidiLevelOfRun;
  }

  return false;
}

Position RenderedPosition::positionAtLeftBoundaryOfBiDiRun() const {
  DCHECK(atLeftBoundaryOfBidiRun());

  if (atLeftmostOffsetInBox())
    return Position::editingPositionOf(m_layoutObject->node(), m_offset);

  return Position::editingPositionOf(
      nextLeafChild()->getLineLayoutItem().node(),
      nextLeafChild()->caretLeftmostOffset());
}

Position RenderedPosition::positionAtRightBoundaryOfBiDiRun() const {
  DCHECK(atRightBoundaryOfBidiRun());

  if (atRightmostOffsetInBox())
    return Position::editingPositionOf(m_layoutObject->node(), m_offset);

  return Position::editingPositionOf(
      prevLeafChild()->getLineLayoutItem().node(),
      prevLeafChild()->caretRightmostOffset());
}

IntRect RenderedPosition::absoluteRect(
    LayoutUnit* extraWidthToEndOfLine) const {
  if (isNull())
    return IntRect();

  IntRect localRect = pixelSnappedIntRect(m_layoutObject->localCaretRect(
      m_inlineBox, m_offset, extraWidthToEndOfLine));
  return localRect == IntRect()
             ? IntRect()
             : m_layoutObject->localToAbsoluteQuad(FloatRect(localRect))
                   .enclosingBoundingBox();
}

void RenderedPosition::positionInGraphicsLayerBacking(
    CompositedSelectionBound& bound,
    bool selectionStart) const {
  bound.layer = nullptr;
  bound.edgeTopInLayer = bound.edgeBottomInLayer = FloatPoint();

  if (isNull())
    return;

  LayoutRect rect = m_layoutObject->localCaretRect(m_inlineBox, m_offset);
  PaintLayer* layer = nullptr;
  if (m_layoutObject->style()->isHorizontalWritingMode()) {
    bound.edgeTopInLayer = m_layoutObject->localToInvalidationBackingPoint(
        rect.minXMinYCorner(), &layer);
    bound.edgeBottomInLayer = m_layoutObject->localToInvalidationBackingPoint(
        rect.minXMaxYCorner(), nullptr);
  } else {
    bound.edgeTopInLayer = m_layoutObject->localToInvalidationBackingPoint(
        rect.minXMinYCorner(), &layer);
    bound.edgeBottomInLayer = m_layoutObject->localToInvalidationBackingPoint(
        rect.maxXMinYCorner(), nullptr);

    // When text is vertical, it looks better for the start handle baseline to
    // be at the starting edge, to enclose the selection fully between the
    // handles.
    if (selectionStart) {
      float xSwap = bound.edgeBottomInLayer.x();
      bound.edgeBottomInLayer.setX(bound.edgeTopInLayer.x());
      bound.edgeTopInLayer.setX(xSwap);
    }

    // Flipped blocks writing mode is not only vertical but also right to left.
    bound.isTextDirectionRTL = m_layoutObject->hasFlippedBlocksWritingMode();
  }

  bound.layer = layer ? layer->graphicsLayerBacking() : nullptr;
}

bool layoutObjectContainsPosition(LayoutObject* target,
                                  const Position& position) {
  for (LayoutObject* layoutObject = layoutObjectFromPosition(position);
       layoutObject && layoutObject->node();
       layoutObject = layoutObject->parent()) {
    if (layoutObject == target)
      return true;
  }
  return false;
}

}  // namespace blink