third_party/WebKit/Source/core/css/CSSCursorImageValue.cpp

/*
 * Copyright (C) 2006 Rob Buis <buis@kde.org>
 *           (C) 2008 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * 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/css/CSSCursorImageValue.h"

#include "core/SVGNames.h"
#include "core/css/CSSImageSetValue.h"
#include "core/fetch/ImageResource.h"
#include "core/style/StyleFetchedImage.h"
#include "core/style/StyleFetchedImageSet.h"
#include "core/style/StyleImage.h"
#include "core/svg/SVGCursorElement.h"
#include "core/svg/SVGLengthContext.h"
#include "core/svg/SVGURIReference.h"
#include "wtf/MathExtras.h"
#include "wtf/text/StringBuilder.h"
#include "wtf/text/WTFString.h"

namespace blink {

static inline SVGCursorElement* resourceReferencedByCursorElement(
    const String& url,
    const TreeScope& treeScope) {
  Element* element =
      SVGURIReference::targetElementFromIRIString(url, treeScope);
  return isSVGCursorElement(element) ? toSVGCursorElement(element) : nullptr;
}

CSSCursorImageValue::CSSCursorImageValue(CSSValue* imageValue,
                                         bool hotSpotSpecified,
                                         const IntPoint& hotSpot)
    : CSSValue(CursorImageClass),
      m_imageValue(imageValue),
      m_hotSpotSpecified(hotSpotSpecified),
      m_hotSpot(hotSpot),
      m_isCachePending(true) {}

CSSCursorImageValue::~CSSCursorImageValue() {}

String CSSCursorImageValue::customCSSText() const {
  StringBuilder result;
  result.append(m_imageValue->cssText());
  if (m_hotSpotSpecified) {
    result.append(' ');
    result.appendNumber(m_hotSpot.x());
    result.append(' ');
    result.appendNumber(m_hotSpot.y());
  }
  return result.toString();
}

SVGCursorElement* CSSCursorImageValue::getSVGCursorElement(
    Element* element) const {
  if (!element || !element->isSVGElement())
    return nullptr;

  if (!hasFragmentInURL())
    return nullptr;

  String url = toCSSImageValue(m_imageValue.get())->url();
  return resourceReferencedByCursorElement(url, element->treeScope());
}

bool CSSCursorImageValue::isCachePending(float deviceScaleFactor) const {
  // Need to delegate completely so that changes in device scale factor can be
  // handled appropriately.
  if (m_imageValue->isImageSetValue())
    return toCSSImageSetValue(*m_imageValue).isCachePending(deviceScaleFactor);
  return m_isCachePending;
}

StyleImage* CSSCursorImageValue::cachedImage(float deviceScaleFactor) const {
  ASSERT(!isCachePending(deviceScaleFactor));

  if (m_imageValue->isImageSetValue())
    return toCSSImageSetValue(*m_imageValue).cachedImage(deviceScaleFactor);
  return m_cachedImage.get();
}

StyleImage* CSSCursorImageValue::cacheImage(const Document& document,
                                            float deviceScaleFactor) {
  if (m_imageValue->isImageSetValue())
    return toCSSImageSetValue(*m_imageValue)
        .cacheImage(document, deviceScaleFactor);

  if (m_isCachePending) {
    m_isCachePending = false;

    // For SVG images we need to lazily substitute in the correct URL. Rather
    // than attempt to change the URL of the CSSImageValue (which would then
    // change behavior like cssText), we create an alternate CSSImageValue to
    // use.
    if (hasFragmentInURL()) {
      CSSImageValue* imageValue = toCSSImageValue(m_imageValue.get());
      // FIXME: This will fail if the <cursor> element is in a shadow DOM
      // (http://crbug/59827)
      if (SVGCursorElement* cursorElement =
              resourceReferencedByCursorElement(imageValue->url(), document)) {
        CSSImageValue* svgImageValue =
            CSSImageValue::create(document.completeURL(
                cursorElement->href()->currentValue()->value()));
        svgImageValue->setReferrer(imageValue->referrer());
        m_cachedImage = svgImageValue->cacheImage(document);
        return m_cachedImage.get();
      }
    }

    if (m_imageValue->isImageValue())
      m_cachedImage = toCSSImageValue(*m_imageValue).cacheImage(document);
  }

  if (m_cachedImage && m_cachedImage->isImageResource())
    return toStyleFetchedImage(m_cachedImage);
  return nullptr;
}

bool CSSCursorImageValue::hasFragmentInURL() const {
  if (m_imageValue->isImageValue()) {
    CSSImageValue* imageValue = toCSSImageValue(m_imageValue.get());
    KURL kurl(ParsedURLString, imageValue->url());
    return kurl.hasFragmentIdentifier();
  }
  return false;
}

String CSSCursorImageValue::cachedImageURL() const {
  if (!m_cachedImage || !m_cachedImage->isImageResource())
    return String();
  return toStyleFetchedImage(m_cachedImage)->cachedImage()->url().getString();
}

void CSSCursorImageValue::clearImageResource() const {
  m_cachedImage = nullptr;
  m_isCachePending = true;
}

bool CSSCursorImageValue::equals(const CSSCursorImageValue& other) const {
  return (m_hotSpotSpecified
              ? other.m_hotSpotSpecified && m_hotSpot == other.m_hotSpot
              : !other.m_hotSpotSpecified) &&
         compareCSSValuePtr(m_imageValue, other.m_imageValue);
}

DEFINE_TRACE_AFTER_DISPATCH(CSSCursorImageValue) {
  visitor->trace(m_imageValue);
  visitor->trace(m_cachedImage);
  CSSValue::traceAfterDispatch(visitor);
}

}  // namespace blink