C++ SVGResources::buildSetOfResources方法代码示例

void SVGResourcesCache::addResourcesFromRenderObject(RenderObject* object, const RenderStyle* style)
{
    ASSERT(object);
    ASSERT(style);
    ASSERT(!m_cache.contains(object));

    const SVGRenderStyle* svgStyle = style->svgStyle();
    ASSERT(svgStyle);

    // Build a list of all resources associated with the passed RenderObject
    SVGResources* resources = new SVGResources;
    if (!resources->buildCachedResources(object, svgStyle)) {
        delete resources;
        return;
    }

    // Put object in cache.
    m_cache.set(object, resources);

    // Run cycle-detection _afterwards_, so self-references can be caught as well.
    SVGResourcesCycleSolver solver(object, resources);
    solver.resolveCycles();

    // Walk resources and register the render object at each resources.
    HashSet<RenderSVGResourceContainer*> resourceSet;
    resources->buildSetOfResources(resourceSet);

    HashSet<RenderSVGResourceContainer*>::iterator end = resourceSet.end();
    for (HashSet<RenderSVGResourceContainer*>::iterator it = resourceSet.begin(); it != end; ++it)
        (*it)->addClient(object);
}

bool SVGResourcesCycleSolver::resourceContainsCycles(RenderObject* renderer) const
{
    ASSERT(renderer);

    // First (first loop iteration) operate on the resources of the given
    // renderer.
    // <marker id="a"> <path marker-start="url(#b)"/> ...
    // <marker id="b" marker-start="url(#a)"/>
    // Then operate on the child resources of the given renderer.
    // <marker id="a"> <path marker-start="url(#b)"/> ...
    // <marker id="b"> <path marker-start="url(#a)"/> ...
    for (RenderObject* child = renderer; child; child = child->nextInPreOrder(renderer)) {
        SVGResources* childResources = SVGResourcesCache::cachedResourcesForRenderObject(child);
        if (!childResources)
            continue;

        // A child of the given 'resource' contains resources.
        HashSet<RenderSVGResourceContainer*> childSet;
        childResources->buildSetOfResources(childSet);

        // Walk all child resources and check whether they reference any resource contained in the resources set.
        HashSet<RenderSVGResourceContainer*>::iterator end = childSet.end();
        for (HashSet<RenderSVGResourceContainer*>::iterator it = childSet.begin(); it != end; ++it) {
            if (m_allResources.contains(*it))
                return true;
        }
    }
    return false;
}

void SVGResourcesCache::addResourcesFromLayoutObject(LayoutObject* object, const ComputedStyle& style)
{
    ASSERT(object);
    ASSERT(!m_cache.contains(object));

    const SVGComputedStyle& svgStyle = style.svgStyle();

    // Build a list of all resources associated with the passed LayoutObject
    OwnPtr<SVGResources> newResources = SVGResources::buildResources(object, svgStyle);
    if (!newResources)
        return;

    // Put object in cache.
    SVGResources* resources = m_cache.set(object, newResources.release()).storedValue->value.get();

    // Run cycle-detection _afterwards_, so self-references can be caught as well.
    SVGResourcesCycleSolver solver(object, resources);
    solver.resolveCycles();

    // Walk resources and register the layout object at each resources.
    HashSet<LayoutSVGResourceContainer*> resourceSet;
    resources->buildSetOfResources(resourceSet);

    for (auto* resourceContainer : resourceSet)
        resourceContainer->addClient(object);
}

void SVGResourcesCache::removeResourcesFromRenderObject(RenderObject* object)
{
    if (!m_cache.contains(object))
        return;

    SVGResources* resources = m_cache.get(object);

    // Walk resources and register the render object at each resources.
    HashSet<RenderSVGResourceContainer*> resourceSet;
    resources->buildSetOfResources(resourceSet);

    HashSet<RenderSVGResourceContainer*>::iterator end = resourceSet.end();
    for (HashSet<RenderSVGResourceContainer*>::iterator it = resourceSet.begin(); it != end; ++it)
        (*it)->removeClient(object);

    delete m_cache.take(object);
}

bool SVGResourcesCycleSolver::resourceContainsCycles(RenderElement& renderer) const
{
    // First operate on the resources of the given renderer.
    // <marker id="a"> <path marker-start="url(#b)"/> ...
    // <marker id="b" marker-start="url(#a)"/>
    if (SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer)) {
        HashSet<RenderSVGResourceContainer*> resourceSet;
        resources->buildSetOfResources(resourceSet);

        // Walk all resources and check wheter they reference any resource contained in the resources set.
        for (auto* resource : resourceSet) {
            if (m_allResources.contains(resource))
                return true;
        }
    }

    // Then operate on the child resources of the given renderer.
    // <marker id="a"> <path marker-start="url(#b)"/> ...
    // <marker id="b"> <path marker-start="url(#a)"/> ...
    for (auto& child : childrenOfType<RenderElement>(renderer)) {
        SVGResources* childResources = SVGResourcesCache::cachedResourcesForRenderObject(child);
        if (!childResources)
            continue;
        
        // A child of the given 'resource' contains resources. 
        HashSet<RenderSVGResourceContainer*> childResourceSet;
        childResources->buildSetOfResources(childResourceSet);

        // Walk all child resources and check wheter they reference any resource contained in the resources set.
        for (auto* resource : childResourceSet) {
            if (m_allResources.contains(resource))
                return true;
        }

        // Walk children recursively, stop immediately if we found a cycle
        if (resourceContainsCycles(child))
            return true;
    }

    return false;
}