Source/WebCore/page/PageSerializer.cpp

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 * in the documentation and/or other materials provided with the
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#include "config.h"
#include "PageSerializer.h"

#include "CSSImageValue.h"
#include "CSSImportRule.h"
#include "CSSStyleRule.h"
#include "CachedImage.h"
#include "Document.h"
#include "Element.h"
#include "HTMLFrameOwnerElement.h"
#include "HTMLHeadElement.h"
#include "HTMLImageElement.h"
#include "HTMLLinkElement.h"
#include "HTMLMetaCharsetParser.h"
#include "HTMLNames.h"
#include "HTMLStyleElement.h"
#include "HTTPParsers.h"
#include "Image.h"
#include "MIMETypeRegistry.h"
#include "MainFrame.h"
#include "MarkupAccumulator.h"
#include "Page.h"
#include "RenderElement.h"
#include "StyleCachedImage.h"
#include "StyleImage.h"
#include "StyleProperties.h"
#include "StyleRule.h"
#include "StyleSheetContents.h"
#include "Text.h"
#include "TextEncoding.h"
#include <wtf/text/CString.h>
#include <wtf/text/StringBuilder.h>
#include <wtf/text/WTFString.h>

namespace WebCore {

static bool isCharsetSpecifyingNode(const Node& node)
{
    if (!node.isHTMLElement())
        return false;

    const HTMLElement& element = toHTMLElement(node);
    if (!element.hasTagName(HTMLNames::metaTag))
        return false;
    HTMLMetaCharsetParser::AttributeList attributes;
    if (element.hasAttributes()) {
        for (unsigned i = 0; i < element.attributeCount(); ++i) {
            const Attribute& attribute = element.attributeAt(i);
            // FIXME: We should deal appropriately with the attribute if they have a namespace.
            attributes.append(std::make_pair(attribute.name().toString(), attribute.value().string()));
        }
    }
    TextEncoding textEncoding = HTMLMetaCharsetParser::encodingFromMetaAttributes(attributes);
    return textEncoding.isValid();
}

static bool shouldIgnoreElement(const Element& element)
{
    return element.hasTagName(HTMLNames::scriptTag) || element.hasTagName(HTMLNames::noscriptTag) || isCharsetSpecifyingNode(element);
}

static const QualifiedName& frameOwnerURLAttributeName(const HTMLFrameOwnerElement& frameOwner)
{
    // FIXME: We should support all frame owners including applets.
    return isHTMLObjectElement(frameOwner) ? HTMLNames::dataAttr : HTMLNames::srcAttr;
}

class SerializerMarkupAccumulator final : public WebCore::MarkupAccumulator {
public:
    SerializerMarkupAccumulator(PageSerializer&, Document&, Vector<Node*>*);
    virtual ~SerializerMarkupAccumulator();

private:
    PageSerializer& m_serializer;
    Document& m_document;

    virtual void appendText(StringBuilder&, const Text&) override;
    virtual void appendElement(StringBuilder&, const Element&, Namespaces*) override;
    virtual void appendCustomAttributes(StringBuilder&, const Element&, Namespaces*) override;
    virtual void appendEndTag(const Node&) override;
};

SerializerMarkupAccumulator::SerializerMarkupAccumulator(PageSerializer& serializer, Document& document, Vector<Node*>* nodes)
    : MarkupAccumulator(nodes, ResolveAllURLs)
    , m_serializer(serializer)
    , m_document(document)
{
    // MarkupAccumulator does not serialize the <?xml ... line, so we add it explicitely to ensure the right encoding is specified.
    if (m_document.isXHTMLDocument() || m_document.xmlStandalone() || m_document.isSVGDocument())
        appendString("<?xml version=\"" + m_document.xmlVersion() + "\" encoding=\"" + m_document.charset() + "\"?>");
}

SerializerMarkupAccumulator::~SerializerMarkupAccumulator()
{
}

void SerializerMarkupAccumulator::appendText(StringBuilder& out, const Text& text)
{
    Element* parent = text.parentElement();
    if (parent && !shouldIgnoreElement(*parent))
        MarkupAccumulator::appendText(out, text);
}

void SerializerMarkupAccumulator::appendElement(StringBuilder& out, const Element& element, Namespaces* namespaces)
{
    if (!shouldIgnoreElement(element))
        MarkupAccumulator::appendElement(out, element, namespaces);

    if (element.hasTagName(HTMLNames::headTag)) {
        out.append("<meta charset=\"");
        out.append(m_document.charset());
        out.append("\">");
    }

    // FIXME: For object (plugins) tags and video tag we could replace them by an image of their current contents.
}

void SerializerMarkupAccumulator::appendCustomAttributes(StringBuilder& out, const Element& element, Namespaces* namespaces)
{
    if (!element.isFrameOwnerElement())
        return;

    const HTMLFrameOwnerElement& frameOwner = toHTMLFrameOwnerElement(element);
    Frame* frame = frameOwner.contentFrame();
    if (!frame)
        return;

    URL url = frame->document()->url();
    if (url.isValid() && !url.isBlankURL())
        return;

    // We need to give a fake location to blank frames so they can be referenced by the serialized frame.
    url = m_serializer.urlForBlankFrame(frame);
    appendAttribute(out, element, Attribute(frameOwnerURLAttributeName(frameOwner), url.string()), namespaces);
}

void SerializerMarkupAccumulator::appendEndTag(const Node& node)
{
    if (node.isElementNode() && !shouldIgnoreElement(toElement(node)))
        MarkupAccumulator::appendEndTag(node);
}

PageSerializer::Resource::Resource()
{
}

PageSerializer::Resource::Resource(const URL& url, const String& mimeType, PassRefPtr<SharedBuffer> data)
    : url(url)
    , mimeType(mimeType)
    , data(data)
{
}

PageSerializer::PageSerializer(Vector<PageSerializer::Resource>* resources)
    : m_resources(resources)
    , m_blankFrameCounter(0)
{
}

void PageSerializer::serialize(Page* page)
{
    serializeFrame(&page->mainFrame());
}

void PageSerializer::serializeFrame(Frame* frame)
{
    Document* document = frame->document();
    URL url = document->url();
    if (!url.isValid() || url.isBlankURL()) {
        // For blank frames we generate a fake URL so they can be referenced by their containing frame.
        url = urlForBlankFrame(frame);
    }

    if (m_resourceURLs.contains(url)) {
        // FIXME: We could have 2 frame with the same URL but which were dynamically changed and have now
        // different content. So we should serialize both and somehow rename the frame src in the containing
        // frame. Arg!
        return;
    }

    Vector<Node*> nodes;
    SerializerMarkupAccumulator accumulator(*this, *document, &nodes);
    TextEncoding textEncoding(document->charset());
    CString data;
    if (!textEncoding.isValid()) {
        // FIXME: iframes used as images trigger this. We should deal with them correctly.
        return;
    }
    String text = accumulator.serializeNodes(*document->documentElement(), 0, IncludeNode);
    CString frameHTML = textEncoding.encode(text.deprecatedCharacters(), text.length(), EntitiesForUnencodables);
    m_resources->append(Resource(url, document->suggestedMIMEType(), SharedBuffer::create(frameHTML.data(), frameHTML.length())));
    m_resourceURLs.add(url);

    for (Vector<Node*>::iterator iter = nodes.begin(); iter != nodes.end(); ++iter) {
        Node* node = *iter;
        if (!node->isElementNode())
            continue;

        Element* element = toElement(node);
        // We have to process in-line style as it might contain some resources (typically background images).
        if (element->isStyledElement())
            retrieveResourcesForProperties(toStyledElement(element)->inlineStyle(), document);

        if (isHTMLImageElement(element)) {
            HTMLImageElement* imageElement = toHTMLImageElement(element);
            URL url = document->completeURL(imageElement->getAttribute(HTMLNames::srcAttr));
            CachedImage* cachedImage = imageElement->cachedImage();
            addImageToResources(cachedImage, imageElement->renderer(), url);
        } else if (element->hasTagName(HTMLNames::linkTag)) {
            HTMLLinkElement* linkElement = toHTMLLinkElement(element);
            if (CSSStyleSheet* sheet = linkElement->sheet()) {
                URL url = document->completeURL(linkElement->getAttribute(HTMLNames::hrefAttr));
                serializeCSSStyleSheet(sheet, url);
                ASSERT(m_resourceURLs.contains(url));
            }
        } else if (isHTMLStyleElement(element)) {
            if (CSSStyleSheet* sheet = toHTMLStyleElement(element)->sheet())
                serializeCSSStyleSheet(sheet, URL());
        }
    }

    for (Frame* childFrame = frame->tree().firstChild(); childFrame; childFrame = childFrame->tree().nextSibling())
        serializeFrame(childFrame);
}

void PageSerializer::serializeCSSStyleSheet(CSSStyleSheet* styleSheet, const URL& url)
{
    StringBuilder cssText;
    for (unsigned i = 0; i < styleSheet->length(); ++i) {
        CSSRule* rule = styleSheet->item(i);
        String itemText = rule->cssText();
        if (!itemText.isEmpty()) {
            cssText.append(itemText);
            if (i < styleSheet->length() - 1)
                cssText.append("\n\n");
        }
        Document* document = styleSheet->ownerDocument();
        // Some rules have resources associated with them that we need to retrieve.
        if (rule->type() == CSSRule::IMPORT_RULE) {
            CSSImportRule* importRule = static_cast<CSSImportRule*>(rule);
            URL importURL = document->completeURL(importRule->href());
            if (m_resourceURLs.contains(importURL))
                continue;
            serializeCSSStyleSheet(importRule->styleSheet(), importURL);
        } else if (rule->type() == CSSRule::FONT_FACE_RULE) {
            // FIXME: Add support for font face rule. It is not clear to me at this point if the actual otf/eot file can
            // be retrieved from the CSSFontFaceRule object.
        } else if (rule->type() == CSSRule::STYLE_RULE)
            retrieveResourcesForRule(static_cast<CSSStyleRule*>(rule)->styleRule(), document);
    }

    if (url.isValid() && !m_resourceURLs.contains(url)) {
        // FIXME: We should check whether a charset has been specified and if none was found add one.
        TextEncoding textEncoding(styleSheet->contents().charset());
        ASSERT(textEncoding.isValid());
        String textString = cssText.toString();
        CString text = textEncoding.encode(textString.deprecatedCharacters(), textString.length(), EntitiesForUnencodables);
        m_resources->append(Resource(url, String("text/css"), SharedBuffer::create(text.data(), text.length())));
        m_resourceURLs.add(url);
    }
}

void PageSerializer::addImageToResources(CachedImage* image, RenderElement* imageRenderer, const URL& url)
{
    if (!url.isValid() || m_resourceURLs.contains(url))
        return;

    if (!image || image->image() == Image::nullImage())
        return;

    RefPtr<SharedBuffer> data = imageRenderer ? image->imageForRenderer(imageRenderer)->data() : 0;
    if (!data)
        data = image->image()->data();

    if (!data) {
        LOG_ERROR("No data for image %s", url.string().utf8().data());
        return;
    }

    String mimeType = image->response().mimeType();
    m_resources->append(Resource(url, mimeType, data));
    m_resourceURLs.add(url);
}

void PageSerializer::retrieveResourcesForRule(StyleRule* rule, Document* document)
{
    retrieveResourcesForProperties(&rule->properties(), document);
}

void PageSerializer::retrieveResourcesForProperties(const StyleProperties* styleDeclaration, Document* document)
{
    if (!styleDeclaration)
        return;

    // The background-image and list-style-image (for ul or ol) are the CSS properties
    // that make use of images. We iterate to make sure we include any other
    // image properties there might be.
    unsigned propertyCount = styleDeclaration->propertyCount();
    for (unsigned i = 0; i < propertyCount; ++i) {
        RefPtr<CSSValue> cssValue = styleDeclaration->propertyAt(i).value();
        if (!cssValue->isImageValue())
            continue;

        StyleImage* styleImage = toCSSImageValue(cssValue.get())->cachedOrPendingImage();
        // Non cached-images are just place-holders and do not contain data.
        if (!styleImage || !styleImage->isCachedImage())
            continue;

        CachedImage* image = static_cast<StyleCachedImage*>(styleImage)->cachedImage();

        URL url = document->completeURL(image->url());
        addImageToResources(image, 0, url);
    }
}

URL PageSerializer::urlForBlankFrame(Frame* frame)
{
    HashMap<Frame*, URL>::iterator iter = m_blankFrameURLs.find(frame);
    if (iter != m_blankFrameURLs.end())
        return iter->value;
    String url = "wyciwyg://frame/" + String::number(m_blankFrameCounter++);
    URL fakeURL(ParsedURLString, url);
    m_blankFrameURLs.add(frame, fakeURL);

    return fakeURL;
}

}