third_party/WebKit/Source/web/WebPageSerializer.cpp

/*
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#include "config.h"
#include "public/web/WebPageSerializer.h"

#include "core/HTMLNames.h"
#include "core/dom/Document.h"
#include "core/dom/Element.h"
#include "core/frame/LocalFrame.h"
#include "core/html/HTMLAllCollection.h"
#include "core/html/HTMLFrameElementBase.h"
#include "core/html/HTMLFrameOwnerElement.h"
#include "core/html/HTMLInputElement.h"
#include "core/html/HTMLTableElement.h"
#include "core/loader/DocumentLoader.h"
#include "core/page/Page.h"
#include "core/page/PageSerializer.h"
#include "platform/SerializedResource.h"
#include "platform/mhtml/MHTMLArchive.h"
#include "platform/mhtml/MHTMLParser.h"
#include "platform/weborigin/KURL.h"
#include "public/platform/WebCString.h"
#include "public/platform/WebString.h"
#include "public/platform/WebURL.h"
#include "public/platform/WebVector.h"
#include "public/web/WebFrame.h"
#include "public/web/WebPageSerializerClient.h"
#include "public/web/WebView.h"
#include "web/WebLocalFrameImpl.h"
#include "web/WebPageSerializerImpl.h"
#include "web/WebViewImpl.h"
#include "wtf/Assertions.h"
#include "wtf/HashMap.h"
#include "wtf/Noncopyable.h"
#include "wtf/Vector.h"
#include "wtf/text/StringConcatenate.h"

namespace blink {

namespace {

using ContentIDMap = WillBeHeapHashMap<RawPtrWillBeMember<Frame>, String>;

class MHTMLPageSerializerDelegate final :
    public NoBaseWillBeGarbageCollected<MHTMLPageSerializerDelegate>,
    public PageSerializer::Delegate {
    WTF_MAKE_NONCOPYABLE(MHTMLPageSerializerDelegate);
public:
    MHTMLPageSerializerDelegate(const ContentIDMap& frameToContentID);
    bool shouldIgnoreAttribute(const Attribute&) override;
    bool rewriteLink(const Element&, String& rewrittenLink) override;

#if ENABLE(OILPAN)
    void trace(Visitor* visitor) { visitor->trace(m_frameToContentID); }
#endif

private:
    const ContentIDMap& m_frameToContentID;
};

MHTMLPageSerializerDelegate::MHTMLPageSerializerDelegate(
    const ContentIDMap& frameToContentID)
    : m_frameToContentID(frameToContentID)
{
}

bool MHTMLPageSerializerDelegate::shouldIgnoreAttribute(const Attribute& attribute)
{
    // TODO(fgorski): Presence of srcset attribute causes MHTML to not display images, as only the value of src
    // is pulled into the archive. Discarding srcset prevents the problem. Long term we should make sure to MHTML
    // plays nicely with srcset.
    return attribute.localName() == HTMLNames::srcsetAttr;
}

bool MHTMLPageSerializerDelegate::rewriteLink(
    const Element& element,
    String& rewrittenLink)
{
    if (!element.isFrameOwnerElement())
        return false;

    auto* frameOwnerElement = toHTMLFrameOwnerElement(&element);
    Frame* frame = frameOwnerElement->contentFrame();
    if (!frame)
        return false;

    KURL cidURI = MHTMLParser::convertContentIDToURI(m_frameToContentID.get(frame));
    ASSERT(cidURI.isValid());

    if (isHTMLFrameElementBase(&element)) {
        rewrittenLink = cidURI.string();
        return true;
    }

    if (isHTMLObjectElement(&element)) {
        Document* doc = frameOwnerElement->contentDocument();
        bool isHandledBySerializer = doc->isHTMLDocument()
            || doc->isXHTMLDocument() || doc->isImageDocument();
        if (isHandledBySerializer) {
            rewrittenLink = cidURI.string();
            return true;
        }
    }

    return false;
}

ContentIDMap generateFrameContentIDs(Page* page)
{
    ContentIDMap frameToContentID;
    int frameID = 0;
    for (Frame* frame = page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
        // TODO(lukasza): Move cid generation to the browser + use base/guid.h
        // (see the draft at crrev.com/1386873003).
        StringBuilder contentIDBuilder;
        contentIDBuilder.appendLiteral("<frame");
        contentIDBuilder.appendNumber(frameID++);
        contentIDBuilder.appendLiteral("@mhtml.blink>");

        frameToContentID.add(frame, contentIDBuilder.toString());
    }
    return frameToContentID;
}

PassRefPtr<SharedBuffer> serializePageToMHTML(Page* page, MHTMLArchive::EncodingPolicy encodingPolicy)
{
    Vector<SerializedResource> resources;
    ContentIDMap frameToContentID = generateFrameContentIDs(page);
    MHTMLPageSerializerDelegate delegate(frameToContentID);
    PageSerializer serializer(resources, &delegate);

    RefPtr<SharedBuffer> output = SharedBuffer::create();
    String boundary = MHTMLArchive::generateMHTMLBoundary();

    Document* document = page->deprecatedLocalMainFrame()->document();
    MHTMLArchive::generateMHTMLHeader(
        boundary, document->title(), document->suggestedMIMEType(), *output);

    for (Frame* frame = page->deprecatedLocalMainFrame(); frame; frame = frame->tree().traverseNext()) {
        // TODO(lukasza): This causes incomplete MHTML for OOPIFs.
        // (crbug.com/538766)
        if (!frame->isLocalFrame())
            continue;

        resources.clear();
        serializer.serializeFrame(*toLocalFrame(frame));

        bool isFirstResource = true;
        for (const SerializedResource& resource : resources) {
            // Frame is the 1st resource (see PageSerializer::serializeFrame doc
            // comment). Frames need a Content-ID header.
            String contentID = isFirstResource ? frameToContentID.get(frame) : String();

            MHTMLArchive::generateMHTMLPart(
                boundary, contentID, encodingPolicy, resource, *output);

            isFirstResource = false;
        }
    }

    MHTMLArchive::generateMHTMLFooter(boundary, *output);
    return output.release();
}

} // namespace

WebCString WebPageSerializer::serializeToMHTML(WebView* view)
{
    RefPtr<SharedBuffer> mhtml = serializePageToMHTML(toWebViewImpl(view)->page(), MHTMLArchive::UseDefaultEncoding);
    // FIXME: we are copying all the data here. Idealy we would have a WebSharedData().
    return WebCString(mhtml->data(), mhtml->size());
}

WebCString WebPageSerializer::serializeToMHTMLUsingBinaryEncoding(WebView* view)
{
    RefPtr<SharedBuffer> mhtml = serializePageToMHTML(toWebViewImpl(view)->page(), MHTMLArchive::UseBinaryEncoding);
    // FIXME: we are copying all the data here. Idealy we would have a WebSharedData().
    return WebCString(mhtml->data(), mhtml->size());
}

bool WebPageSerializer::serialize(
    WebLocalFrame* frame,
    WebPageSerializerClient* client,
    const WebVector<std::pair<WebURL, WebString>>& urlsToLocalPaths)
{
    WebPageSerializerImpl serializerImpl(frame, client, urlsToLocalPaths);
    return serializerImpl.serialize();
}

WebString WebPageSerializer::generateMetaCharsetDeclaration(const WebString& charset)
{
    // TODO(yosin) We should call |PageSerializer::metaCharsetDeclarationOf()|.
    String charsetString = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=" + static_cast<const String&>(charset) + "\">";
    return charsetString;
}

WebString WebPageSerializer::generateMarkOfTheWebDeclaration(const WebURL& url)
{
    StringBuilder builder;
    builder.append("\n<!-- ");
    builder.append(PageSerializer::markOfTheWebDeclaration(url));
    builder.append(" -->\n");
    return builder.toString();
}

WebString WebPageSerializer::generateBaseTagDeclaration(const WebString& baseTarget)
{
    // TODO(yosin) We should call |PageSerializer::baseTagDeclarationOf()|.
    if (baseTarget.isEmpty())
        return String("<base href=\".\">");
    String baseString = "<base href=\".\" target=\"" + static_cast<const String&>(baseTarget) + "\">";
    return baseString;
}

} // namespace blink