Source/core/html/track/WebVTTParser.h

/*
 * Copyright (C) 2011 Google Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 */

#ifndef WebVTTParser_h
#define WebVTTParser_h

#include "HTMLNames.h"
#include "RuntimeEnabledFeatures.h"
#include "core/dom/DocumentFragment.h"
#include "core/fetch/TextResourceDecoder.h"
#include "core/html/track/TextTrackCue.h"
#include "core/html/track/VTTRegion.h"
#include "core/html/track/WebVTTTokenizer.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/text/StringBuilder.h"

namespace WebCore {

using namespace HTMLNames;

class Document;

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

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

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

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

    static inline bool isRecognizedTag(const AtomicString& tagName)
    {
        return tagName == iTag
            || tagName == bTag
            || tagName == uTag
            || tagName == rubyTag
            || tagName == rtTag;
    }

    static inline bool isASpace(char 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(char 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 String collectDigits(const String&, unsigned*);
    static String collectWord(const String&, unsigned*);
    static double collectTimeStamp(const String&, unsigned*);

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

    // 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);

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

private:
    WebVTTParser(WebVTTParserClient*, Document&);

    Document* m_document;
    ParseState m_state;

    bool hasRequiredFileIdentifier(const String& line);
    ParseState collectCueId(const String&);
    ParseState collectTimingsAndSettings(const String&);
    ParseState collectCueText(const String&, bool);
    ParseState ignoreBadCue(const String&);

    void createNewCue();
    void resetCueValues();

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

    void skipWhiteSpace(const String&, unsigned*);
    static void skipLineTerminator(const String& data, unsigned*);
    static String collectNextLine(const String& data, unsigned*);

    String m_currentHeaderName;
    String m_currentHeaderValue;

    RefPtr<TextResourceDecoder> m_decoder;
    String m_currentId;
    double m_currentStartTime;
    double m_currentEndTime;
    StringBuilder m_currentContent;
    String m_currentSettings;

    WebVTTParserClient* m_client;

    Vector<RefPtr<TextTrackCue> > m_cuelist;

    Vector<RefPtr<VTTRegion> > m_regionList;
};

} // namespace WebCore

#endif