void SVGUseElement::expandUseElementsInShadowTree(Node* element)
{
// Why expand the <use> elements in the shadow tree here, and not just
// do this directly in buildShadowTree, if we encounter a <use> element?
//
// Short answer: Because we may miss to expand some elements. Ie. if a <symbol>
// contains <use> tags, we'd miss them. So once we're done with settin' up the
// actual shadow tree (after the special case modification for svg/symbol) we have
// to walk it completely and expand all <use> elements.
if (element->hasTagName(SVGNames::useTag)) {
SVGUseElement* use = static_cast<SVGUseElement*>(element);
String id = SVGURIReference::getTarget(use->href());
Element* targetElement = document()->getElementById(id);
SVGElement* target = 0;
if (targetElement && targetElement->isSVGElement())
target = static_cast<SVGElement*>(targetElement);
// Don't ASSERT(target) here, it may be "pending", too.
if (target) {
// Setup sub-shadow tree root node
RefPtr<SVGElement> cloneParent = new SVGGElement(SVGNames::gTag, document());
// Spec: In the generated content, the 'use' will be replaced by 'g', where all attributes from the
// 'use' element except for x, y, width, height and xlink:href are transferred to the generated 'g' element.
transferUseAttributesToReplacedElement(use, cloneParent.get());
// Spec: An additional transformation translate(x,y) is appended to the end
// (i.e., right-side) of the transform attribute on the generated 'g', where x
// and y represent the values of the x and y attributes on the 'use' element.
if (use->x().value() != 0.0 || use->y().value() != 0.0) {
if (!cloneParent->hasAttribute(SVGNames::transformAttr)) {
String transformString = String::format("translate(%f, %f)", use->x().value(), use->y().value());
cloneParent->setAttribute(SVGNames::transformAttr, transformString);
} else {
String transformString = String::format(" translate(%f, %f)", use->x().value(), use->y().value());
const AtomicString& transformAttribute = cloneParent->getAttribute(SVGNames::transformAttr);
cloneParent->setAttribute(SVGNames::transformAttr, transformAttribute + transformString);
}
}
ExceptionCode ec = 0;
// For instance <use> on <foreignObject> (direct case).
if (isDisallowedElement(target)) {
// We still have to setup the <use> replacment (<g>). Otherwhise
// associateInstancesWithShadowTreeElements() makes wrong assumptions.
// Replace <use> with referenced content.
ASSERT(use->parentNode());
use->parentNode()->replaceChild(cloneParent.release(), use, ec);
ASSERT(ec == 0);
return;
}
RefPtr<Node> newChild = target->cloneNode(true);
// We don't walk the target tree element-by-element, and clone each element,
// but instead use cloneNode(deep=true). This is an optimization for the common
// case where <use> doesn't contain disallowed elements (ie. <foreignObject>).
// Though if there are disallowed elements in the subtree, we have to remove them.
// For instance: <use> on <g> containing <foreignObject> (indirect case).
if (subtreeContainsDisallowedElement(newChild.get()))
removeDisallowedElementsFromSubtree(newChild.get());
SVGElement* newChildPtr = 0;
if (newChild->isSVGElement())
newChildPtr = static_cast<SVGElement*>(newChild.get());
ASSERT(newChildPtr);
cloneParent->appendChild(newChild.release(), ec);
ASSERT(ec == 0);
// Replace <use> with referenced content.
ASSERT(use->parentNode());
use->parentNode()->replaceChild(cloneParent.release(), use, ec);
ASSERT(ec == 0);
// Handle use referencing <svg> special case
if (target->hasTagName(SVGNames::svgTag))
alterShadowTreeForSVGTag(newChildPtr);
// Immediately stop here, and restart expanding.
expandUseElementsInShadowTree(m_shadowTreeRootElement.get());
return;
}
}
for (RefPtr<Node> child = element->firstChild(); child; child = child->nextSibling())
expandUseElementsInShadowTree(child.get());
}
