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      1 /*
      2  * Copyright (C) 2011 Google Inc.  All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef VTTParser_h
     32 #define VTTParser_h
     33 
     34 #include "core/HTMLNames.h"
     35 #include "core/dom/DocumentFragment.h"
     36 #include "core/html/parser/TextResourceDecoder.h"
     37 #include "core/html/track/vtt/BufferedLineReader.h"
     38 #include "core/html/track/vtt/VTTCue.h"
     39 #include "core/html/track/vtt/VTTRegion.h"
     40 #include "core/html/track/vtt/VTTTokenizer.h"
     41 #include "platform/heap/Handle.h"
     42 #include "wtf/PassOwnPtr.h"
     43 #include "wtf/text/StringBuilder.h"
     44 
     45 namespace WebCore {
     46 
     47 class Document;
     48 class VTTScanner;
     49 
     50 class VTTParserClient {
     51 public:
     52     virtual ~VTTParserClient() { }
     53 
     54     virtual void newCuesParsed() = 0;
     55     virtual void newRegionsParsed() = 0;
     56     virtual void fileFailedToParse() = 0;
     57 };
     58 
     59 class VTTParser FINAL : public NoBaseWillBeGarbageCollectedFinalized<VTTParser> {
     60 public:
     61     enum ParseState {
     62         Initial,
     63         Header,
     64         Id,
     65         TimingsAndSettings,
     66         CueText,
     67         BadCue
     68     };
     69 
     70     static PassOwnPtrWillBeRawPtr<VTTParser> create(VTTParserClient* client, Document& document)
     71     {
     72         return adoptPtrWillBeNoop(new VTTParser(client, document));
     73     }
     74 
     75     static inline bool isRecognizedTag(const AtomicString& tagName)
     76     {
     77         return tagName == HTMLNames::iTag
     78             || tagName == HTMLNames::bTag
     79             || tagName == HTMLNames::uTag
     80             || tagName == HTMLNames::rubyTag
     81             || tagName == HTMLNames::rtTag;
     82     }
     83     static inline bool isASpace(UChar c)
     84     {
     85         // 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).
     86         return c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r';
     87     }
     88     static inline bool isValidSettingDelimiter(UChar c)
     89     {
     90         // ... a WebVTT cue consists of zero or more of the following components, in any order, separated from each other by one or more
     91         // U+0020 SPACE characters or U+0009 CHARACTER TABULATION (tab) characters.
     92         return c == ' ' || c == '\t';
     93     }
     94     static bool collectTimeStamp(const String&, double& timeStamp);
     95 
     96     // Useful functions for parsing percentage settings.
     97     static bool parseFloatPercentageValue(VTTScanner& valueScanner, float& percentage);
     98     static bool parseFloatPercentageValuePair(VTTScanner&, char, FloatPoint&);
     99 
    100     // Create the DocumentFragment representation of the WebVTT cue text.
    101     static PassRefPtrWillBeRawPtr<DocumentFragment> createDocumentFragmentFromCueText(Document&, const String&);
    102 
    103     // Input data to the parser to parse.
    104     void parseBytes(const char* data, unsigned length);
    105     void flush();
    106 
    107     // Transfers ownership of last parsed cues to caller.
    108     void getNewCues(WillBeHeapVector<RefPtrWillBeMember<VTTCue> >&);
    109     void getNewRegions(WillBeHeapVector<RefPtrWillBeMember<VTTRegion> >&);
    110 
    111     void trace(Visitor*);
    112 
    113 private:
    114     VTTParser(VTTParserClient*, Document&);
    115 
    116     RawPtrWillBeMember<Document> m_document;
    117     ParseState m_state;
    118 
    119     void parse();
    120     void flushPendingCue();
    121     bool hasRequiredFileIdentifier(const String& line);
    122     ParseState collectCueId(const String&);
    123     ParseState collectTimingsAndSettings(const String&);
    124     ParseState collectCueText(const String&);
    125     ParseState recoverCue(const String&);
    126     ParseState ignoreBadCue(const String&);
    127 
    128     void createNewCue();
    129     void resetCueValues();
    130 
    131     void collectMetadataHeader(const String&);
    132     void createNewRegion(const String& headerValue);
    133 
    134     static bool collectTimeStamp(VTTScanner& input, double& timeStamp);
    135 
    136     BufferedLineReader m_lineReader;
    137     OwnPtr<TextResourceDecoder> m_decoder;
    138     AtomicString m_currentId;
    139     double m_currentStartTime;
    140     double m_currentEndTime;
    141     StringBuilder m_currentContent;
    142     String m_currentSettings;
    143 
    144     VTTParserClient* m_client;
    145 
    146     WillBeHeapVector<RefPtrWillBeMember<VTTCue> > m_cueList;
    147 
    148     WillBeHeapVector<RefPtrWillBeMember<VTTRegion> > m_regionList;
    149 };
    150 
    151 } // namespace WebCore
    152 
    153 #endif
    154