svguseelement.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
    Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <[e-mail]>
                  2004, 2005, 2006, 2007 Rob Buis <[e-mail]>

    This file is part of the KDE project

    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 "config.h"

// Dump SVGElementInstance object tree - useful to debug instanceRoot problems
// #define DUMP_INSTANCE_TREE

// Dump the deep-expanded shadow tree (where the renderes are built from)
// #define DUMP_SHADOW_TREE

#if ENABLE(SVG)
#include "SVGUseElement.h"

#include "CSSStyleSelector.h"
#include "CString.h"
#include "Document.h"
#include "Event.h"
#include "EventListener.h"
#include "HTMLNames.h"
#include "NodeRenderStyle.h"
#include "RegisteredEventListener.h"
#include "RenderSVGTransformableContainer.h"
#include "SVGElementInstance.h"
#include "SVGElementInstanceList.h"
#include "SVGGElement.h"
#include "SVGLength.h"
#include "SVGPreserveAspectRatio.h"
#include "SVGSMILElement.h"
#include "SVGSVGElement.h"
#include "SVGSymbolElement.h"
#include "XLinkNames.h"
#include "XMLSerializer.h"

namespace WebCore {

SVGUseElement::SVGUseElement(const QualifiedName& tagName, Document* doc)
    : SVGStyledTransformableElement(tagName, doc)
    , SVGTests()
    , SVGLangSpace()
    , SVGExternalResourcesRequired()
    , SVGURIReference()
    , m_x(this, SVGNames::xAttr, LengthModeWidth)
    , m_y(this, SVGNames::yAttr, LengthModeHeight)
    , m_width(this, SVGNames::widthAttr, LengthModeWidth)
    , m_height(this, SVGNames::heightAttr, LengthModeHeight)
{
}

SVGUseElement::~SVGUseElement()
{
}

SVGElementInstance* SVGUseElement::instanceRoot() const
{
    return m_targetElementInstance.get();
}

SVGElementInstance* SVGUseElement::animatedInstanceRoot() const
{
    // FIXME: Implement me.
    return 0;
}
 
void SVGUseElement::parseMappedAttribute(MappedAttribute* attr)
{
    if (attr->name() == SVGNames::xAttr)
        setXBaseValue(SVGLength(LengthModeWidth, attr->value()));
    else if (attr->name() == SVGNames::yAttr)
        setYBaseValue(SVGLength(LengthModeHeight, attr->value()));
    else if (attr->name() == SVGNames::widthAttr) {
        setWidthBaseValue(SVGLength(LengthModeWidth, attr->value()));
        if (widthBaseValue().value(this) < 0.0)
            document()->accessSVGExtensions()->reportError("A negative value for use attribute <width> is not allowed");
    } else if (attr->name() == SVGNames::heightAttr) {
        setHeightBaseValue(SVGLength(LengthModeHeight, attr->value()));
        if (heightBaseValue().value(this) < 0.0)
            document()->accessSVGExtensions()->reportError("A negative value for use attribute <height> is not allowed");
    } else {
        if (SVGTests::parseMappedAttribute(attr))
            return;
        if (SVGLangSpace::parseMappedAttribute(attr))
            return;
        if (SVGExternalResourcesRequired::parseMappedAttribute(attr))
            return;
        if (SVGURIReference::parseMappedAttribute(attr))
            return;
        SVGStyledTransformableElement::parseMappedAttribute(attr);
    }
}

void SVGUseElement::insertedIntoDocument()
{
    SVGElement::insertedIntoDocument();
    buildPendingResource();
}

void SVGUseElement::removedFromDocument()
{
    m_targetElementInstance = 0;
    m_shadowTreeRootElement = 0;
    SVGElement::removedFromDocument();
}

void SVGUseElement::svgAttributeChanged(const QualifiedName& attrName)
{
    SVGStyledTransformableElement::svgAttributeChanged(attrName);

    if (!attached())
        return;

    if (attrName == SVGNames::xAttr || attrName == SVGNames::yAttr ||
        attrName == SVGNames::widthAttr || attrName == SVGNames::heightAttr ||
        SVGTests::isKnownAttribute(attrName) ||
        SVGLangSpace::isKnownAttribute(attrName) ||
        SVGExternalResourcesRequired::isKnownAttribute(attrName) ||
        SVGURIReference::isKnownAttribute(attrName) ||
        SVGStyledTransformableElement::isKnownAttribute(attrName)) {
        buildPendingResource();

        if (m_shadowTreeRootElement)
            m_shadowTreeRootElement->setChanged();
    }
}

void SVGUseElement::childrenChanged(bool changedByParser, Node* beforeChange, Node* afterChange, int childCountDelta)
{
    SVGElement::childrenChanged(changedByParser, beforeChange, afterChange, childCountDelta);

    if (!attached())
        return;

    buildPendingResource();

    if (m_shadowTreeRootElement)
        m_shadowTreeRootElement->setChanged();
}
 
static bool shadowTreeContainsChangedNodes(SVGElementInstance* target)
{
    if (target->needsUpdate())
        return true;

    for (SVGElementInstance* instance = target->firstChild(); instance; instance = instance->nextSibling())
        if (shadowTreeContainsChangedNodes(instance))
            return true;

    return false;
}

void SVGUseElement::recalcStyle(StyleChange change)
{
    if (attached() && changed() && shadowTreeContainsChangedNodes(m_targetElementInstance.get())) {
        buildPendingResource();

        if (m_shadowTreeRootElement)
            m_shadowTreeRootElement->setChanged();
    }

    SVGStyledElement::recalcStyle(change);

    // The shadow tree root element is NOT a direct child element of us.
    // So we have to take care it receives style updates, manually.
    if (!m_shadowTreeRootElement || !m_shadowTreeRootElement->attached())
        return;

    // Mimic Element::recalcStyle(). The main difference is that we don't call attach() on the
    // shadow tree root element, but call attachShadowTree() here. Calling attach() will crash
    // as the shadow tree root element has no (direct) parent node. Yes, shadow trees are tricky.
    if (change >= Inherit || m_shadowTreeRootElement->changed()) {
        RefPtr<RenderStyle> newStyle = document()->styleSelector()->styleForElement(m_shadowTreeRootElement.get());
        StyleChange ch = Node::diff(m_shadowTreeRootElement->renderStyle(), newStyle.get());
        if (ch == Detach) {
            ASSERT(m_shadowTreeRootElement->attached());
            m_shadowTreeRootElement->detach();
            attachShadowTree();

            // attach recalulates the style for all children. No need to do it twice.
            m_shadowTreeRootElement->setChanged(NoStyleChange);
            m_shadowTreeRootElement->setHasChangedChild(false);
            return;
        }
    }

    // Only change==Detach needs special treatment, for anything else recalcStyle() works.
    m_shadowTreeRootElement->recalcStyle(change);
}

#ifdef DUMP_INSTANCE_TREE
void dumpInstanceTree(unsigned int& depth, String& text, SVGElementInstance* targetInstance)
{
    SVGElement* element = targetInstance->correspondingElement();
    ASSERT(element);

    String elementId = element->getIDAttribute();
    String elementNodeName = element->nodeName();
    String parentNodeName = element->parentNode() ? element->parentNode()->nodeName() : "null";
    String firstChildNodeName = element->firstChild() ? element->firstChild()->nodeName() : "null";

    for (unsigned int i = 0; i < depth; ++i)
        text += "  ";

    text += String::format("SVGElementInstance this=%p, (parentNode=%s, firstChild=%s, correspondingElement=%s (%p), shadowTreeElement=%p, id=%s)\n",
                           targetInstance, parentNodeName.latin1().data(), firstChildNodeName.latin1().data(), elementNodeName.latin1().data(),
                           element, targetInstance->shadowTreeElement(), elementId.latin1().data());

    for (unsigned int i = 0; i < depth; ++i)
        text += "  ";

    HashSet<SVGElementInstance*> elementInstances = element->instancesForElement();
    text += String::format("Corresponding element is associated with %i instance(s):\n", elementInstances.size());

    HashSet<SVGElementInstance*>::iterator end = elementInstances.end();
    for (HashSet<SVGElementInstance*>::iterator it = elementInstances.begin(); it != end; ++it) {
        for (unsigned int i = 0; i < depth; ++i)
            text += "  ";

        text += String::format(" -> SVGElementInstance this=%p, (refCount: %i, shadowTreeElement in document? %i)\n",
                               *it, (*it)->refCount(), (*it)->shadowTreeElement()->inDocument());
    }

    ++depth;

    for (SVGElementInstance* instance = targetInstance->firstChild(); instance; instance = instance->nextSibling())
        dumpInstanceTree(depth, text, instance);

    --depth;
}
#endif

static bool isDisallowedElement(Node* element)
{
#if ENABLE(SVG_FOREIGN_OBJECT)
    // <foreignObject> should never be contained in a <use> tree. Too dangerous side effects possible.
    if (element->hasTagName(SVGNames::foreignObjectTag))
        return true;
#endif
#if ENABLE(SVG_ANIMATION)
    if (SVGSMILElement::isSMILElement(element))
        return true;
#endif

    return false;
}

static bool subtreeContainsDisallowedElement(Node* start)
{
    if (isDisallowedElement(start))
        return true;

    for (Node* cur = start->firstChild(); cur; cur = cur->nextSibling()) {
        if (subtreeContainsDisallowedElement(cur))
            return true;
    }

    return false;
}

void SVGUseElement::buildPendingResource()
{
    String id = SVGURIReference::getTarget(href());
    Element* targetElement = document()->getElementById(id);

    if (!targetElement) {
        // TODO: We want to deregister as pending resource, if our href() changed!
        // TODO: Move to svgAttributeChanged, once we're fixing use & the new dynamic update concept.
        document()->accessSVGExtensions()->addPendingResource(id, this);
        return;
    }

    // Do not build the shadow/instance tree for <use> elements living in a shadow tree.
    // The will be expanded soon anyway - see expandUseElementsInShadowTree().
    Node* parent = parentNode();
    while (parent) {
        if (parent->isShadowNode())