Source/core/html/track/WebVTTTokenizer.cpp

/*
 * 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.
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 * 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
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "config.h"

#include "core/html/track/WebVTTTokenizer.h"

#include "core/xml/parser/MarkupTokenizerInlines.h"

namespace WebCore {

#define WEBVTT_BEGIN_STATE(stateName) BEGIN_STATE(WebVTTTokenizerState, stateName)
#define WEBVTT_ADVANCE_TO(stateName) ADVANCE_TO(WebVTTTokenizerState, stateName)

WebVTTTokenizer::WebVTTTokenizer()
    : m_inputStreamPreprocessor(this)
{
    reset();
}

template <typename CharacterType>
inline bool vectorEqualsString(const Vector<CharacterType, 32>& vector, const String& string)
{
    if (vector.size() != string.length())
        return false;

    if (!string.length())
        return true;

    return equal(string.impl(), vector.data(), vector.size());
}

void WebVTTTokenizer::reset()
{
    m_state = WebVTTTokenizerState::DataState;
    m_token = 0;
    m_buffer.clear();
}

bool WebVTTTokenizer::nextToken(SegmentedString& source, WebVTTToken& token)
{
    // If we have a token in progress, then we're supposed to be called back
    // with the same token so we can finish it.
    ASSERT(!m_token || m_token == &token || token.type() == WebVTTTokenTypes::Uninitialized);
    m_token = &token;

    if (source.isEmpty() || !m_inputStreamPreprocessor.peek(source))
        return haveBufferedCharacterToken();

    UChar cc = m_inputStreamPreprocessor.nextInputCharacter();

    // 4.8.10.13.4 WebVTT cue text tokenizer
    switch (m_state) {
    WEBVTT_BEGIN_STATE(DataState) {
        if (cc == '&') {
            m_buffer.append(static_cast<LChar>(cc));
            WEBVTT_ADVANCE_TO(EscapeState);
        } else if (cc == '<') {
            // FIXME: the explicit Vector conversion copies into a temporary
            // and is wasteful.
            if (m_token->type() == WebVTTTokenTypes::Uninitialized
                || vectorEqualsString<UChar>(Vector<UChar, 32>(m_token->characters()), emptyString()))
                WEBVTT_ADVANCE_TO(TagState);
            else
                return emitAndResumeIn(source, WebVTTTokenizerState::TagState);
        } else if (cc == kEndOfFileMarker)
            return emitEndOfFile(source);
        else {
            bufferCharacter(cc);
            WEBVTT_ADVANCE_TO(DataState);
        }
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(EscapeState) {
        if (cc == ';') {
            if (vectorEqualsString(m_buffer, "&amp"))
                bufferCharacter('&');
            else if (vectorEqualsString(m_buffer, "&lt"))
                bufferCharacter('<');
            else if (vectorEqualsString(m_buffer, "&gt"))
                bufferCharacter('>');
            else {
                m_buffer.append(static_cast<LChar>(cc));
                m_token->appendToCharacter(m_buffer);
            }
            m_buffer.clear();
            WEBVTT_ADVANCE_TO(DataState);
        } else if (isASCIIAlphanumeric(cc)) {
            m_buffer.append(static_cast<LChar>(cc));
            WEBVTT_ADVANCE_TO(EscapeState);
        } else if (cc == kEndOfFileMarker) {
            m_token->appendToCharacter(m_buffer);
            return emitEndOfFile(source);
        } else {
            if (!vectorEqualsString(m_buffer, "&"))
                m_token->appendToCharacter(m_buffer);
            m_buffer.clear();
            WEBVTT_ADVANCE_TO(DataState);
        }
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(TagState) {
        if (isTokenizerWhitespace(cc)) {
            m_token->beginEmptyStartTag();
            WEBVTT_ADVANCE_TO(StartTagAnnotationState);
        } else if (cc == '.') {
            m_token->beginEmptyStartTag();
            WEBVTT_ADVANCE_TO(StartTagClassState);
        } else if (cc == '/') {
            WEBVTT_ADVANCE_TO(EndTagOpenState);
        } else if (WTF::isASCIIDigit(cc)) {
            m_token->beginTimestampTag(cc);
            WEBVTT_ADVANCE_TO(TimestampTagState);
        } else if (cc == '>' || cc == kEndOfFileMarker) {
            m_token->beginEmptyStartTag();
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        } else {
            m_token->beginStartTag(cc);
            WEBVTT_ADVANCE_TO(StartTagState);
        }
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(StartTagState) {
        if (isTokenizerWhitespace(cc))
            WEBVTT_ADVANCE_TO(StartTagAnnotationState);
        else if (cc == '.')
            WEBVTT_ADVANCE_TO(StartTagClassState);
        else if (cc == '>' || cc == kEndOfFileMarker)
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        else {
            m_token->appendToName(cc);
            WEBVTT_ADVANCE_TO(StartTagState);
        }
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(StartTagClassState) {
        if (isTokenizerWhitespace(cc)) {
            m_token->addNewClass();
            WEBVTT_ADVANCE_TO(StartTagAnnotationState);
        } else if (cc == '.') {
            m_token->addNewClass();
            WEBVTT_ADVANCE_TO(StartTagClassState);
        } else if (cc == '>' || cc == kEndOfFileMarker) {
            m_token->addNewClass();
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        } else {
            m_token->appendToClass(cc);
            WEBVTT_ADVANCE_TO(StartTagClassState);
        }

    }
    END_STATE()

    WEBVTT_BEGIN_STATE(StartTagAnnotationState) {
        if (cc == '>' || cc == kEndOfFileMarker) {
            m_token->addNewAnnotation();
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        }
        m_token->appendToAnnotation(cc);
        WEBVTT_ADVANCE_TO(StartTagAnnotationState);
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(EndTagOpenState) {
        if (cc == '>' || cc == kEndOfFileMarker) {
            m_token->beginEndTag('\0');
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        }
        m_token->beginEndTag(cc);
        WEBVTT_ADVANCE_TO(EndTagState);
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(EndTagState) {
        if (cc == '>' || cc == kEndOfFileMarker)
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        m_token->appendToName(cc);
        WEBVTT_ADVANCE_TO(EndTagState);
    }
    END_STATE()

    WEBVTT_BEGIN_STATE(TimestampTagState) {
        if (cc == '>' || cc == kEndOfFileMarker)
            return emitAndResumeIn(source, WebVTTTokenizerState::DataState);
        m_token->appendToTimestamp(cc);
        WEBVTT_ADVANCE_TO(TimestampTagState);
    }
    END_STATE()

    }

    ASSERT_NOT_REACHED();
    return false;
}

}