third_party/WebKit/Source/core/layout/HitTestResult.cpp

/*
 * Copyright (C) 2006, 2008, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
 *
 * 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.
 *
*/

#include "core/layout/HitTestResult.h"

#include "core/HTMLNames.h"
#include "core/InputTypeNames.h"
#include "core/dom/PseudoElement.h"
#include "core/dom/shadow/FlatTreeTraversal.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/editing/EditingUtilities.h"
#include "core/editing/FrameSelection.h"
#include "core/frame/LocalFrame.h"
#include "core/html/HTMLAreaElement.h"
#include "core/html/HTMLImageElement.h"
#include "core/html/HTMLInputElement.h"
#include "core/html/HTMLMapElement.h"
#include "core/html/HTMLMediaElement.h"
#include "core/html/HTMLTextAreaElement.h"
#include "core/html/parser/HTMLParserIdioms.h"
#include "core/layout/LayoutImage.h"
#include "core/svg/SVGElement.h"
#include "platform/geometry/Region.h"
#include "platform/scroll/Scrollbar.h"

namespace blink {

using namespace HTMLNames;

HitTestResult::HitTestResult()
    : m_hitTestRequest(HitTestRequest::ReadOnly | HitTestRequest::Active),
      m_cacheable(true),
      m_isOverWidget(false) {}

HitTestResult::HitTestResult(const HitTestRequest& request,
                             const LayoutPoint& point)
    : m_hitTestLocation(point),
      m_hitTestRequest(request),
      m_cacheable(true),
      m_pointInInnerNodeFrame(point),
      m_isOverWidget(false) {}

HitTestResult::HitTestResult(const HitTestRequest& request,
                             const LayoutPoint& centerPoint,
                             unsigned topPadding,
                             unsigned rightPadding,
                             unsigned bottomPadding,
                             unsigned leftPadding)
    : m_hitTestLocation(centerPoint,
                        topPadding,
                        rightPadding,
                        bottomPadding,
                        leftPadding),
      m_hitTestRequest(request),
      m_cacheable(true),
      m_pointInInnerNodeFrame(centerPoint),
      m_isOverWidget(false) {}

HitTestResult::HitTestResult(const HitTestRequest& otherRequest,
                             const HitTestLocation& other)
    : m_hitTestLocation(other),
      m_hitTestRequest(otherRequest),
      m_cacheable(true),
      m_pointInInnerNodeFrame(m_hitTestLocation.point()),
      m_isOverWidget(false) {}

HitTestResult::HitTestResult(const HitTestResult& other)
    : m_hitTestLocation(other.m_hitTestLocation),
      m_hitTestRequest(other.m_hitTestRequest),
      m_cacheable(other.m_cacheable),
      m_innerNode(other.innerNode()),
      m_innerPossiblyPseudoNode(other.m_innerPossiblyPseudoNode),
      m_pointInInnerNodeFrame(other.m_pointInInnerNodeFrame),
      m_localPoint(other.localPoint()),
      m_innerURLElement(other.URLElement()),
      m_scrollbar(other.scrollbar()),
      m_isOverWidget(other.isOverWidget()) {
  // Only copy the NodeSet in case of list hit test.
  m_listBasedTestResult = other.m_listBasedTestResult
                              ? new NodeSet(*other.m_listBasedTestResult)
                              : nullptr;
}

HitTestResult::~HitTestResult() {}

HitTestResult& HitTestResult::operator=(const HitTestResult& other) {
  m_hitTestLocation = other.m_hitTestLocation;
  m_hitTestRequest = other.m_hitTestRequest;
  populateFromCachedResult(other);

  return *this;
}

bool HitTestResult::equalForCacheability(const HitTestResult& other) const {
  return m_hitTestRequest.equalForCacheability(other.m_hitTestRequest) &&
         m_innerNode == other.innerNode() &&
         m_innerPossiblyPseudoNode == other.innerPossiblyPseudoNode() &&
         m_pointInInnerNodeFrame == other.m_pointInInnerNodeFrame &&
         m_localPoint == other.localPoint() &&
         m_innerURLElement == other.URLElement() &&
         m_scrollbar == other.scrollbar() &&
         m_isOverWidget == other.isOverWidget();
}

void HitTestResult::cacheValues(const HitTestResult& other) {
  *this = other;
  m_hitTestRequest =
      other.m_hitTestRequest.type() & ~HitTestRequest::AvoidCache;
}

void HitTestResult::populateFromCachedResult(const HitTestResult& other) {
  m_innerNode = other.innerNode();
  m_innerPossiblyPseudoNode = other.innerPossiblyPseudoNode();
  m_pointInInnerNodeFrame = other.m_pointInInnerNodeFrame;
  m_localPoint = other.localPoint();
  m_innerURLElement = other.URLElement();
  m_scrollbar = other.scrollbar();
  m_isOverWidget = other.isOverWidget();
  m_cacheable = other.m_cacheable;

  // Only copy the NodeSet in case of list hit test.
  m_listBasedTestResult = other.m_listBasedTestResult
                              ? new NodeSet(*other.m_listBasedTestResult)
                              : nullptr;
}

DEFINE_TRACE(HitTestResult) {
  visitor->trace(m_innerNode);
  visitor->trace(m_innerPossiblyPseudoNode);
  visitor->trace(m_innerURLElement);
  visitor->trace(m_scrollbar);
  visitor->trace(m_listBasedTestResult);
}

PositionWithAffinity HitTestResult::position() const {
  if (!m_innerPossiblyPseudoNode)
    return PositionWithAffinity();
  LayoutObject* layoutObject = this->layoutObject();
  if (!layoutObject)
    return PositionWithAffinity();
  if (m_innerPossiblyPseudoNode->isPseudoElement() &&
      m_innerPossiblyPseudoNode->getPseudoId() == PseudoIdBefore)
    return mostForwardCaretPosition(
        Position(m_innerNode, PositionAnchorType::BeforeChildren));
  return layoutObject->positionForPoint(localPoint());
}

LayoutObject* HitTestResult::layoutObject() const {
  return m_innerNode ? m_innerNode->layoutObject() : 0;
}

void HitTestResult::setToShadowHostIfInUserAgentShadowRoot() {
  if (Node* node = innerNode()) {
    if (ShadowRoot* containingShadowRoot = node->containingShadowRoot()) {
      if (containingShadowRoot->type() == ShadowRootType::UserAgent)
        setInnerNode(node->ownerShadowHost());
    }
  }
}

HTMLAreaElement* HitTestResult::imageAreaForImage() const {
  ASSERT(m_innerNode);
  HTMLImageElement* imageElement = nullptr;
  if (isHTMLImageElement(m_innerNode)) {
    imageElement = toHTMLImageElement(m_innerNode);
  } else if (m_innerNode->isInShadowTree()) {
    if (m_innerNode->containingShadowRoot()->type() ==
        ShadowRootType::UserAgent) {
      if (isHTMLImageElement(m_innerNode->ownerShadowHost()))
        imageElement = toHTMLImageElement(m_innerNode->ownerShadowHost());
    }
  }

  if (!imageElement || !imageElement->layoutObject() ||
      !imageElement->layoutObject()->isBox())
    return nullptr;

  HTMLMapElement* map = imageElement->treeScope().getImageMap(
      imageElement->fastGetAttribute(usemapAttr));
  if (!map)
    return nullptr;

  return map->areaForPoint(localPoint(), imageElement->layoutObject());
}

void HitTestResult::setInnerNode(Node* n) {
  m_innerPossiblyPseudoNode = n;
  if (n && n->isPseudoElement())
    n = toPseudoElement(n)->findAssociatedNode();
  m_innerNode = n;
  if (HTMLAreaElement* area = imageAreaForImage()) {
    m_innerNode = area;
    m_innerPossiblyPseudoNode = area;
  }
}

void HitTestResult::setURLElement(Element* n) {
  m_innerURLElement = n;
}

void HitTestResult::setScrollbar(Scrollbar* s) {
  m_scrollbar = s;
}

LocalFrame* HitTestResult::innerNodeFrame() const {
  if (m_innerNode)
    return m_innerNode->document().frame();
  return nullptr;
}

bool HitTestResult::isSelected() const {
  if (!m_innerNode)
    return false;

  if (LocalFrame* frame = m_innerNode->document().frame())
    return frame->selection().contains(m_hitTestLocation.point());
  return false;
}

String HitTestResult::title(TextDirection& dir) const {
  dir = LTR;
  // Find the title in the nearest enclosing DOM node.
  // For <area> tags in image maps, walk the tree for the <area>, not the <img> using it.
  if (m_innerNode.get())
    m_innerNode->updateDistribution();
  for (Node* titleNode = m_innerNode.get(); titleNode;
       titleNode = FlatTreeTraversal::parent(*titleNode)) {
    if (titleNode->isElementNode()) {
      String title = toElement(titleNode)->title();
      if (!title.isNull()) {
        if (LayoutObject* layoutObject = titleNode->layoutObject())
          dir = layoutObject->style()->direction();
        return title;
      }
    }
  }
  return String();
}

const AtomicString& HitTestResult::altDisplayString() const {
  Node* innerNodeOrImageMapImage = this->innerNodeOrImageMapImage();
  if (!innerNodeOrImageMapImage)
    return nullAtom;

  if (isHTMLImageElement(*innerNodeOrImageMapImage)) {
    HTMLImageElement& image = toHTMLImageElement(*innerNodeOrImageMapImage);
    return image.getAttribute(altAttr);
  }

  if (isHTMLInputElement(*innerNodeOrImageMapImage)) {
    HTMLInputElement& input = toHTMLInputElement(*innerNodeOrImageMapImage);
    return input.alt();
  }

  return nullAtom;
}

Image* HitTestResult::image() const {
  Node* innerNodeOrImageMapImage = this->innerNodeOrImageMapImage();
  if (!innerNodeOrImageMapImage)
    return nullptr;

  LayoutObject* layoutObject = innerNodeOrImageMapImage->layoutObject();
  if (layoutObject && layoutObject->isImage()) {
    LayoutImage* image = toLayoutImage(layoutObject);
    if (image->cachedImage() && !image->cachedImage()->errorOccurred())
      return image->cachedImage()->getImage();
  }

  return nullptr;
}

IntRect HitTestResult::imageRect() const {
  if (!image())
    return IntRect();
  return innerNodeOrImageMapImage()
      ->layoutBox()
      ->absoluteContentQuad()
      .enclosingBoundingBox();
}

KURL HitTestResult::absoluteImageURL() const {
  Node* innerNodeOrImageMapImage = this->innerNodeOrImageMapImage();
  if (!innerNodeOrImageMapImage)
    return KURL();

  AtomicString urlString;
  // Always return a url for image elements and input elements with type=image, even if they
  // don't have a LayoutImage (e.g. because the image didn't load and we are using an alt container).
  // For other elements we don't create alt containers so ensure they contain a loaded image.
  if (isHTMLImageElement(*innerNodeOrImageMapImage) ||
      (isHTMLInputElement(*innerNodeOrImageMapImage) &&
       toHTMLInputElement(innerNodeOrImageMapImage)->type() ==
           InputTypeNames::image))
    urlString = toElement(*innerNodeOrImageMapImage).imageSourceURL();
  else if ((innerNodeOrImageMapImage->layoutObject() &&
            innerNodeOrImageMapImage->layoutObject()->isImage()) &&
           (isHTMLEmbedElement(*innerNodeOrImageMapImage) ||
            isHTMLObjectElement(*innerNodeOrImageMapImage) ||
            isSVGImageElement(*innerNodeOrImageMapImage)))
    urlString = toElement(*innerNodeOrImageMapImage).imageSourceURL();
  if (urlString.isEmpty())
    return KURL();

  return innerNodeOrImageMapImage->document().completeURL(
      stripLeadingAndTrailingHTMLSpaces(urlString));
}

KURL HitTestResult::absoluteMediaURL() const {
  if (HTMLMediaElement* mediaElt = mediaElement())
    return mediaElt->currentSrc();
  return KURL();
}

HTMLMediaElement* HitTestResult::mediaElement() const {
  if (!m_innerNode)
    return nullptr;

  if (!(m_innerNode->layoutObject() && m_innerNode->layoutObject()->isMedia()))
    return nullptr;

  if (isHTMLMediaElement(*m_innerNode))
    return toHTMLMediaElement(m_innerNode);
  return nullptr;
}

KURL HitTestResult::absoluteLinkURL() const {
  if (!m_innerURLElement)
    return KURL();
  return m_innerURLElement->hrefURL();
}

bool HitTestResult::isLiveLink() const {
  return m_innerURLElement && m_innerURLElement->isLiveLink();
}

bool HitTestResult::isOverLink() const {
  return m_innerURLElement && m_innerURLElement->isLink();
}

String HitTestResult::textContent() const {
  if (!m_innerURLElement)
    return String();
  return m_innerURLElement->textContent();
}

// FIXME: This function needs a better name and may belong in a different class. It's not
// really isContentEditable(); it's more like needsEditingContextMenu(). In many ways, this
// function would make more sense in the ContextMenu class, except that WebElementDictionary
// hooks into it. Anyway, we should architect this better.
bool HitTestResult::isContentEditable() const {
  if (!m_innerNode)
    return false;

  if (isHTMLTextAreaElement(*m_innerNode))
    return !toHTMLTextAreaElement(*m_innerNode).isDisabledOrReadOnly();

  if (isHTMLInputElement(*m_innerNode)) {
    HTMLInputElement& inputElement = toHTMLInputElement(*m_innerNode);
    return !inputElement.isDisabledOrReadOnly() && inputElement.isTextField();
  }

  return hasEditableStyle(*m_innerNode);
}

ListBasedHitTestBehavior HitTestResult::addNodeToListBasedTestResult(
    Node* node,
    const HitTestLocation& location,
    const LayoutRect& rect) {
  // If not a list-based test, stop testing because the hit has been found.
  if (!hitTestRequest().listBased())
    return StopHitTesting;

  if (!node)
    return ContinueHitTesting;

  mutableListBasedTestResult().add(node);

  if (hitTestRequest().penetratingList())
    return ContinueHitTesting;

  return rect.contains(LayoutRect(location.boundingBox())) ? StopHitTesting
                                                           : ContinueHitTesting;
}

ListBasedHitTestBehavior HitTestResult::addNodeToListBasedTestResult(
    Node* node,
    const HitTestLocation& location,
    const Region& region) {
  // If not a list-based test, stop testing because the hit has been found.
  if (!hitTestRequest().listBased())
    return StopHitTesting;

  if (!node)
    return ContinueHitTesting;

  mutableListBasedTestResult().add(node);

  if (hitTestRequest().penetratingList())
    return ContinueHitTesting;

  return region.contains(location.boundingBox()) ? StopHitTesting
                                                 : ContinueHitTesting;
}

void HitTestResult::append(const HitTestResult& other) {
  ASSERT(hitTestRequest().listBased());

  if (!m_scrollbar && other.scrollbar()) {
    setScrollbar(other.scrollbar());
  }

  if (!m_innerNode && other.innerNode()) {
    m_innerNode = other.innerNode();
    m_innerPossiblyPseudoNode = other.innerPossiblyPseudoNode();
    m_localPoint = other.localPoint();
    m_pointInInnerNodeFrame = other.m_pointInInnerNodeFrame;
    m_innerURLElement = other.URLElement();
    m_isOverWidget = other.isOverWidget();
  }

  if (other.m_listBasedTestResult) {
    NodeSet& set = mutableListBasedTestResult();
    for (NodeSet::const_iterator it = other.m_listBasedTestResult->begin(),
                                 last = other.m_listBasedTestResult->end();
         it != last; ++it)
      set.add(it->get());
  }
}

const HitTestResult::NodeSet& HitTestResult::listBasedTestResult() const {
  if (!m_listBasedTestResult)
    m_listBasedTestResult = new NodeSet;
  return *m_listBasedTestResult;
}

HitTestResult::NodeSet& HitTestResult::mutableListBasedTestResult() {
  if (!m_listBasedTestResult)
    m_listBasedTestResult = new NodeSet;
  return *m_listBasedTestResult;
}

void HitTestResult::resolveRectBasedTest(
    Node* resolvedInnerNode,
    const LayoutPoint& resolvedPointInMainFrame) {
  ASSERT(isRectBasedTest());
  ASSERT(m_hitTestLocation.containsPoint(FloatPoint(resolvedPointInMainFrame)));
  m_hitTestLocation = HitTestLocation(resolvedPointInMainFrame);
  m_pointInInnerNodeFrame = resolvedPointInMainFrame;
  m_innerNode = nullptr;
  m_innerPossiblyPseudoNode = nullptr;
  m_listBasedTestResult = nullptr;

  // Update the HitTestResult as if the supplied node had been hit in normal point-based hit-test.
  // Note that we don't know the local point after a rect-based hit-test, but we never use
  // it so shouldn't bother with the cost of computing it.
  resolvedInnerNode->layoutObject()->updateHitTestResult(*this, LayoutPoint());
  ASSERT(!isRectBasedTest());
}

Element* HitTestResult::innerElement() const {
  for (Node* node = m_innerNode.get(); node;
       node = FlatTreeTraversal::parent(*node)) {
    if (node->isElementNode())
      return toElement(node);
  }

  return nullptr;
}

Node* HitTestResult::innerNodeOrImageMapImage() const {
  if (!m_innerNode)
    return nullptr;

  HTMLImageElement* imageMapImageElement = nullptr;
  if (isHTMLAreaElement(m_innerNode))
    imageMapImageElement = toHTMLAreaElement(m_innerNode)->imageElement();
  else if (isHTMLMapElement(m_innerNode))
    imageMapImageElement = toHTMLMapElement(m_innerNode)->imageElement();

  if (!imageMapImageElement)
    return m_innerNode.get();

  return imageMapImageElement;
}

}  // namespace blink