root/Source/core/html/track/vtt/VTTParser.h

INCLUDED FROM

/*
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 * Redistribution and use in source and binary forms, with or without
 * 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 without specific prior written permission.
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#ifndef VTTParser_h
#define VTTParser_h

#include "HTMLNames.h"
#include "RuntimeEnabledFeatures.h"
#include "core/dom/DocumentFragment.h"
#include "core/html/parser/TextResourceDecoder.h"
#include "core/html/track/vtt/BufferedLineReader.h"
#include "core/html/track/vtt/VTTCue.h"
#include "core/html/track/vtt/VTTRegion.h"
#include "core/html/track/vtt/VTTTokenizer.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/text/StringBuilder.h"

namespace WebCore {

class Document;
class VTTScanner;

class VTTParserClient {
public:
    virtual ~VTTParserClient() { }

    virtual void newCuesParsed() = 0;
    virtual void newRegionsParsed() = 0;
    virtual void fileFailedToParse() = 0;
};

class VTTParser FINAL {
public:
    enum ParseState {
        Initial,
        Header,
        Id,
        TimingsAndSettings,
        CueText,
        BadCue
    };

    static PassOwnPtr<VTTParser> create(VTTParserClient* client, Document& document)
    {
        return adoptPtr(new VTTParser(client, document));
    }

    static inline bool isRecognizedTag(const AtomicString& tagName)
    {
        return tagName == HTMLNames::iTag
            || tagName == HTMLNames::bTag
            || tagName == HTMLNames::uTag
            || tagName == HTMLNames::rubyTag
            || tagName == HTMLNames::rtTag;
    }
    static inline bool isASpace(UChar c)
    {
        // WebVTT space characters are U+0020 SPACE, U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), and U+000D CARRIAGE RETURN    (CR).
        return c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r';
    }
    static inline bool isValidSettingDelimiter(UChar c)
    {
        // ... a WebVTT cue consists of zero or more of the following components, in any order, separated from each other by one or more
        // U+0020 SPACE characters or U+0009 CHARACTER TABULATION (tab) characters.
        return c == ' ' || c == '\t';
    }
    static bool collectTimeStamp(const String&, double& timeStamp);

    // Useful functions for parsing percentage settings.
    static bool parseFloatPercentageValue(VTTScanner& valueScanner, float& percentage);
    static bool parseFloatPercentageValuePair(VTTScanner&, char, FloatPoint&);

    // Create the DocumentFragment representation of the WebVTT cue text.
    static PassRefPtr<DocumentFragment> createDocumentFragmentFromCueText(Document&, const String&);

    // Input data to the parser to parse.
    void parseBytes(const char* data, unsigned length);
    void flush();

    // Transfers ownership of last parsed cues to caller.
    void getNewCues(Vector<RefPtr<VTTCue> >&);
    void getNewRegions(Vector<RefPtr<VTTRegion> >&);

private:
    VTTParser(VTTParserClient*, Document&);

    Document* m_document;
    ParseState m_state;

    void parse();
    void flushPendingCue();
    bool hasRequiredFileIdentifier(const String& line);
    ParseState collectCueId(const String&);
    ParseState collectTimingsAndSettings(const String&);
    ParseState collectCueText(const String&);
    ParseState recoverCue(const String&);
    ParseState ignoreBadCue(const String&);

    void createNewCue();
    void resetCueValues();

    void collectMetadataHeader(const String&);
    void createNewRegion(const String& headerValue);

    static bool collectTimeStamp(VTTScanner& input, double& timeStamp);

    BufferedLineReader m_lineReader;
    OwnPtr<TextResourceDecoder> m_decoder;
    AtomicString m_currentId;
    double m_currentStartTime;
    double m_currentEndTime;
    StringBuilder m_currentContent;
    String m_currentSettings;

    VTTParserClient* m_client;

    Vector<RefPtr<VTTCue> > m_cuelist;

    Vector<RefPtr<VTTRegion> > m_regionList;
};

} // namespace WebCore

#endif