C++ AtomicString::isEmpty方法代码示例

void SVGFilterBuilder::add(const AtomicString& id, RefPtr<FilterEffect> effect)
{
    if (id.isEmpty()) {
        m_lastEffect = effect;
        return;
    }

    if (m_builtinEffects.contains(id))
        return;

    m_lastEffect = effect;
    m_namedEffects.set(id, m_lastEffect);
}

static URL getURLForImageElement(Element& element)
{
    // FIXME: Later this code should be shared with Chromium somehow. Chances are all platforms want it.
    AtomicString urlString;
    if (isHTMLImageElement(element) || isHTMLInputElement(element))
        urlString = element.getAttribute(HTMLNames::srcAttr);
    else if (element.hasTagName(SVGNames::imageTag))
        urlString = element.getAttribute(XLinkNames::hrefAttr);
    else if (element.hasTagName(HTMLNames::embedTag) || isHTMLObjectElement(element))
        urlString = element.imageSourceURL();

    return urlString.isEmpty() ? URL() : element.document().completeURL(stripLeadingAndTrailingHTMLSpaces(urlString));
}

void ImageLoader::updateFromElement()
{
    // If we're not making renderers for the page, then don't load images.  We don't want to slow
    // down the raw HTML parsing case by loading images we don't intend to display.
    Element* elem = element();
    Document* doc = elem->document();
    if (!doc->renderer())
        return;

    AtomicString attr = elem->getAttribute(elem->imageSourceAttributeName());

    if (attr == m_failedLoadURL)
        return;

    // Do not load any image if the 'src' attribute is missing or if it is
    // an empty string referring to a local file. The latter condition is
    // a quirk that preserves old behavior that Dashboard widgets
    // need (<rdar://problem/5994621>).
    CachedImage* newImage = 0;
    if (!(attr.isNull() || attr.isEmpty() && doc->baseURI().isLocalFile())) {
        if (m_loadManually) {
            doc->docLoader()->setAutoLoadImages(false);
            newImage = new CachedImage(sourceURI(attr));
            newImage->setLoading(true);
            newImage->setDocLoader(doc->docLoader());
            doc->docLoader()->m_documentResources.set(newImage->url(), newImage);
        } else
            newImage = doc->docLoader()->requestImage(sourceURI(attr));

        // If we do not have an image here, it means that a cross-site
        // violation occurred.
        m_failedLoadURL = !newImage ? attr : AtomicString();
    }
    
    CachedImage* oldImage = m_image.get();
    if (newImage != oldImage) {
        setLoadingImage(newImage);
        if (newImage)
            newImage->addClient(this);
        if (oldImage)
            oldImage->removeClient(this);
    }

    if (RenderObject* renderer = elem->renderer()) {
        if (!renderer->isImage())
            return;

        static_cast<RenderImage*>(renderer)->resetAnimation();
    }
}

const char* WebSocketHandshake::readHTTPHeaders(const char* start, const char* end)
{
    m_response.clearHeaderFields();

    AtomicString name;
    AtomicString value;
    bool sawSecWebSocketAcceptHeaderField = false;
    bool sawSecWebSocketProtocolHeaderField = false;
    const char* p = start;
    for (; p < end; p++) {
        size_t consumedLength = parseHTTPHeader(p, end - p, m_failureReason, name, value);
        if (!consumedLength)
            return 0;
        p += consumedLength;

        // Stop once we consumed an empty line.
        if (name.isEmpty())
            break;

        // Sec-WebSocket-Extensions may be split. We parse and check the
        // header value every time the header appears.
        if (equalIgnoringCase("Sec-WebSocket-Extensions", name)) {
            if (!m_extensionDispatcher.processHeaderValue(value)) {
                m_failureReason = formatHandshakeFailureReason(m_extensionDispatcher.failureReason());
                return 0;
            }
        } else if (equalIgnoringCase("Sec-WebSocket-Accept", name)) {
            if (sawSecWebSocketAcceptHeaderField) {
                m_failureReason = formatHandshakeFailureReason("'Sec-WebSocket-Accept' header must not appear more than once in a response");
                return 0;
            }
            m_response.addHeaderField(name, value);
            sawSecWebSocketAcceptHeaderField = true;
        } else if (equalIgnoringCase("Sec-WebSocket-Protocol", name)) {
            if (sawSecWebSocketProtocolHeaderField) {
                m_failureReason = formatHandshakeFailureReason("'Sec-WebSocket-Protocol' header must not appear more than once in a response");
                return 0;
            }
            m_response.addHeaderField(name, value);
            sawSecWebSocketProtocolHeaderField = true;
        } else {
            m_response.addHeaderField(name, value);
        }
    }

    String extensions = m_extensionDispatcher.acceptedExtensions();
    if (!extensions.isEmpty())
        m_response.addHeaderField("Sec-WebSocket-Extensions", AtomicString(extensions));
    return p;
}

void SVGDocumentExtensions::addPendingResource(const AtomicString& id, Element* element)
{
    ASSERT(element);

    if (id.isEmpty())
        return;

    HashMap<AtomicString, OwnPtr<SVGPendingElements> >::AddResult result = m_pendingResources.add(id, nullptr);
    if (result.isNewEntry)
        result.iterator->value = adoptPtr(new SVGPendingElements);
    result.iterator->value->add(element);

    element->setHasPendingResources();
}

static void appendNamespace(Vector<UChar>& result, const AtomicString& prefix, const AtomicString& ns, HashMap<AtomicStringImpl*, AtomicStringImpl*>& namespaces)
{
    if (ns.isEmpty())
        return;

    // Use emptyAtoms's impl() for both null and empty strings since the HashMap can't handle 0 as a key
    AtomicStringImpl* pre = prefix.isEmpty() ? emptyAtom.impl() : prefix.impl();
    AtomicStringImpl* foundNS = namespaces.get(pre);
    if (foundNS != ns.impl()) {
        namespaces.set(pre, ns.impl());
        DEFINE_STATIC_LOCAL(const String, xmlns, ("xmlns"));
        result.append(' ');
        append(result, xmlns);
        if (!prefix.isEmpty()) {
            result.append(':');
            append(result, prefix);
        }

        result.append('=');
        result.append('"');
        appendAttributeValue(result, ns, false);
        result.append('"');
    }

void HTMLBRElement::collectStyleForPresentationAttribute(const QualifiedName& name, const AtomicString& value, MutableStyleProperties& style)
{
    if (name == clearAttr) {
        // If the string is empty, then don't add the clear property.
        // <br clear> and <br clear=""> are just treated like <br> by Gecko, Mac IE, etc. -dwh
        if (!value.isEmpty()) {
            if (equalIgnoringCase(value, "all"))
                addPropertyToPresentationAttributeStyle(style, CSSPropertyClear, CSSValueBoth);
            else
                addPropertyToPresentationAttributeStyle(style, CSSPropertyClear, value);
        }
    } else
        HTMLElement::collectStyleForPresentationAttribute(name, value, style);
}

void HTMLFontElement::collectStyleForPresentationAttribute(const QualifiedName& name, const AtomicString& value, MutableStylePropertySet* style)
{
    if (name == sizeAttr) {
        CSSValueID size = CSSValueInvalid;
        if (cssValueFromFontSizeNumber(value, size))
            addPropertyToPresentationAttributeStyle(style, CSSPropertyFontSize, size);
    } else if (name == colorAttr)
        addHTMLColorToStyle(style, CSSPropertyColor, value);
    else if (name == faceAttr && !value.isEmpty()) {
        if (RefPtrWillBeRawPtr<CSSValueList> fontFaceValue = cssValuePool().createFontFaceValue(value))
            style->setProperty(CSSProperty(CSSPropertyFontFamily, fontFaceValue.release()));
    } else
        HTMLElement::collectStyleForPresentationAttribute(name, value, style);
}

void MarkupAccumulator::appendNamespace(StringBuilder& result, const AtomicString& prefix, const AtomicString& namespaceURI, Namespaces& namespaces, bool allowEmptyDefaultNS)
{
    namespaces.checkConsistency();
    if (namespaceURI.isEmpty()) {
        // http://www.whatwg.org/specs/web-apps/current-work/multipage/the-xhtml-syntax.html#xml-fragment-serialization-algorithm
        if (allowEmptyDefaultNS && namespaces.get(emptyAtom.impl())) {
            result.append(' ');
            result.append(xmlnsAtom.string());
            result.appendLiteral("=\"\"");
        }
        return;
    }

    // Use emptyAtoms's impl() for both null and empty strings since the HashMap can't handle 0 as a key
    AtomicStringImpl* pre = prefix.isEmpty() ? emptyAtom.impl() : prefix.impl();
    AtomicStringImpl* foundNS = namespaces.get(pre);
    if (foundNS != namespaceURI.impl()) {
        namespaces.set(pre, namespaceURI.impl());
        // Add namespace to prefix pair so we can do constraint checking later.
        if (inXMLFragmentSerialization() && !prefix.isEmpty())
            namespaces.set(namespaceURI.impl(), pre);
        // Make sure xml prefix and namespace are always known to uphold the constraints listed at http://www.w3.org/TR/xml-names11/#xmlReserved.
        if (namespaceURI.impl() == XMLNames::xmlNamespaceURI.impl())
            return;
        result.append(' ');
        result.append(xmlnsAtom.string());
        if (!prefix.isEmpty()) {
            result.append(':');
            result.append(prefix);
        }

        result.append('=');
        result.append('"');
        appendAttributeValue(result, namespaceURI, false);
        result.append('"');
    }
}

bool SelectorChecker::checkPseudoClass(const CSSSelector& selector)
{
    switch (selector.pseudoType()) {
    case CSSSelector::PseudoFocus:
        m_matchedFocusSelector = true;
        return matchesFocusPseudoClass(m_element);

    case CSSSelector::PseudoHover:
        m_matchedHoverSelector = true;
        return m_element.hovered();

    case CSSSelector::PseudoActive:
        m_matchedActiveSelector = true;
        return m_element.active();

    case CSSSelector::PseudoLang:
    {
        AtomicString value = m_element.computeInheritedLanguage();
        const AtomicString& argument = selector.argument();
        if (value.isEmpty() || !value.startsWith(argument, false))
            break;
        if (value.length() != argument.length() && value[argument.length()] != '-')
            break;
        return true;
    }

    case CSSSelector::PseudoHost:
    {
        // We can only get here if the selector was defined in the right
        // scope so we don't need to check it.

        // For empty parameter case, i.e. just :host or :host().
        if (!selector.selectorList())
            return true;
        for (const CSSSelector* current = selector.selectorList()->first(); current; current = CSSSelectorList::next(*current)) {
            if (match(*current))
                return true;
        }
        return false;
    }

    case CSSSelector::PseudoUnknown:
    case CSSSelector::PseudoNotParsed:
    case CSSSelector::PseudoUserAgentCustomElement:
        return false;
    }
    ASSERT_NOT_REACHED();
    return false;
}

void SearchPopupMenu::saveRecentSearches(const AtomicString& name, const Vector<String>& searchItems)
{
    String fileName = String("PROGDIR:Searches");
    if (!name.isEmpty())
        fileName = fileName + "_" + name;

    FILE *file = fopen(fileName.latin1().data(), "w");
    if (file) {
        Vector<String>::iterator end = (Vector<String>::iterator)searchItems.end();
        for (Vector<String>::iterator it = (Vector<String>::iterator)searchItems.begin(); it < end; it++)
            fprintf(file, "%s\n", (*it).utf8().data());

        fclose(file);
    }
}

void MarkupAccumulator::appendNamespace(StringBuilder& result, const AtomicString& prefix, const AtomicString& namespaceURI, Namespaces& namespaces)
{
    namespaces.checkConsistency();
    if (namespaceURI.isEmpty())
        return;
        
    // Use emptyAtoms's impl() for both null and empty strings since the HashMap can't handle 0 as a key
    AtomicStringImpl* pre = prefix.isEmpty() ? emptyAtom.impl() : prefix.impl();
    AtomicStringImpl* foundNS = namespaces.get(pre);
    if (foundNS != namespaceURI.impl()) {
        namespaces.set(pre, namespaceURI.impl());
        result.append(' ');
        result.append(xmlnsAtom.string());
        if (!prefix.isEmpty()) {
            result.append(':');
            result.append(prefix);
        }

        result.append('=');
        result.append('"');
        appendAttributeValue(result, namespaceURI, false);
        result.append('"');
    }
}

void Attr::setPrefix(const AtomicString& prefix, ExceptionCode& ec)
{
    ec = 0;
    checkSetPrefix(prefix, ec);
    if (ec)
        return;

    if ((prefix == xmlnsAtom && namespaceURI() != XMLNSNames::xmlnsNamespaceURI)
        || static_cast<Attr*>(this)->qualifiedName() == xmlnsAtom) {
        ec = NAMESPACE_ERR;
        return;
    }

    m_attribute->setPrefix(prefix.isEmpty() ? AtomicString() : prefix);
}

void SVGDocumentExtensions::addPendingResource(const AtomicString& id, Element* element)
{
    ASSERT(element);
    ASSERT(element->inDocument());

    if (id.isEmpty())
        return;

    WillBeHeapHashMap<AtomicString, OwnPtrWillBeMember<SVGPendingElements>>::AddResult result = m_pendingResources.add(id, nullptr);
    if (result.isNewEntry)
        result.storedValue->value = adoptPtrWillBeNoop(new SVGPendingElements);
    result.storedValue->value->add(element);

    element->setHasPendingResources();
}

AtomicString FrameTree::uniqueChildName(const AtomicString& requestedName) const
{
    if (!requestedName.isEmpty() && !child(requestedName) && requestedName != "_blank")
        return requestedName;

    // Create a repeatable name for a child about to be added to us. The name must be
    // unique within the frame tree. The string we generate includes a "path" of names
    // from the root frame down to us. For this path to be unique, each set of siblings must
    // contribute a unique name to the path, which can't collide with any HTML-assigned names.
    // We generate this path component by index in the child list along with an unlikely
    // frame name that can't be set in HTML because it collides with comment syntax.

    const char framePathPrefix[] = "<!--framePath ";
    const int framePathPrefixLength = 14;
    const int framePathSuffixLength = 3;

    // Find the nearest parent that has a frame with a path in it.
    Vector<Frame*, 16> chain;
    Frame* frame;
    for (frame = m_thisFrame; frame; frame = frame->tree()->parent()) {
        if (frame->tree()->name().startsWith(framePathPrefix))
            break;
        chain.append(frame);
    }
    String name;
    name += framePathPrefix;
    if (frame)
        name += frame->tree()->name().domString().substring(framePathPrefixLength,
            frame->tree()->name().length() - framePathPrefixLength - framePathSuffixLength);
    for (int i = chain.size() - 1; i >= 0; --i) {
        frame = chain[i];
        name += "/";
        name += frame->tree()->name();
    }

    // Suffix buffer has more than enough space for:
    //     10 characters before the number
    //     a number (3 digits for the highest this gets in practice, 20 digits for the largest 64-bit integer)
    //     6 characters after the number
    //     trailing null byte
    // But we still use snprintf just to be extra-safe.
    char suffix[40];
    snprintf(suffix, sizeof(suffix), "/<!--frame%u-->-->", childCount());

    name += suffix;

    return AtomicString(name);
}