WebVTTParser::ParseState WebVTTParser::collectCueId(const String& line)
{
if (line.contains("-->"))
return collectTimingsAndSettings(line);
m_currentId = line;
return TimingsAndSettings;
}
void WebVTTParser::parseBytes(const char* data, unsigned length)
{
// 4.8.10.13.3 WHATWG WebVTT Parser algorithm.
// 1-3 - Initial setup.
unsigned position = 0;
while (position < length) {
String line = collectNextLine(data, length, &position);
switch (m_state) {
case Initial:
// Buffer up at least 9 bytes before proceeding with checking for the file identifier.
m_identifierData.append(data, length);
if (m_identifierData.size() < bomLength + fileIdentifierLength)
return;
// 4-12 - Collect the first line and check for "WEBVTT".
if (!hasRequiredFileIdentifier()) {
if (m_client)
m_client->fileFailedToParse();
return;
}
m_state = Header;
m_identifierData.clear();
break;
case Header:
// 13-18 - Allow a header (comment area) under the WEBVTT line.
if (line.isEmpty())
m_state = Id;
break;
case Id:
// 19-29 - Allow any number of line terminators, then initialize new cue values.
if (line.isEmpty())
break;
resetCueValues();
// 30-39 - Check if this line contains an optional identifier or timing data.
m_state = collectCueId(line);
break;
case TimingsAndSettings:
// 40 - Collect cue timings and settings.
m_state = collectTimingsAndSettings(line);
break;
case CueText:
// 41-53 - Collect the cue text, create a cue, and add it to the output.
m_state = collectCueText(line, length, position);
break;
case BadCue:
// 54-62 - Collect and discard the remaining cue.
m_state = ignoreBadCue(line);
break;
}
}
}
VTTParser::ParseState VTTParser::recoverCue(const String& line)
{
// Step 17 and 21.
resetCueValues();
// Step 22.
return collectTimingsAndSettings(line);
}
void VTTParser::parse()
{
// WebVTT parser algorithm. (5.1 WebVTT file parsing.)
// Steps 1 - 3 - Initial setup.
String line;
while (m_lineReader.getLine(line)) {
switch (m_state) {
case Initial:
// Steps 4 - 9 - Check for a valid WebVTT signature.
if (!hasRequiredFileIdentifier(line)) {
if (m_client)
m_client->fileFailedToParse();
return;
}
m_state = Header;
break;
case Header:
// Steps 10 - 14 - Allow a header (comment area) under the WEBVTT line.
collectMetadataHeader(line);
if (line.isEmpty()) {
if (m_client && m_regionList.size())
m_client->newRegionsParsed();
m_state = Id;
break;
}
// Step 15 - Break out of header loop if the line could be a timestamp line.
if (line.contains("-->"))
m_state = recoverCue(line);
// Step 16 - Line is not the empty string and does not contain "-->".
break;
case Id:
// Steps 17 - 20 - Allow any number of line terminators, then initialize new cue values.
if (line.isEmpty())
break;
// Step 21 - Cue creation (start a new cue).
resetCueValues();
// Steps 22 - 25 - Check if this line contains an optional identifier or timing data.
m_state = collectCueId(line);
break;
case TimingsAndSettings:
// Steps 26 - 27 - Discard current cue if the line is empty.
if (line.isEmpty()) {
m_state = Id;
break;
}
// Steps 28 - 29 - Collect cue timings and settings.
m_state = collectTimingsAndSettings(line);
break;
case CueText:
// Steps 31 - 41 - Collect the cue text, create a cue, and add it to the output.
m_state = collectCueText(line);
break;
case BadCue:
// Steps 42 - 48 - Discard lines until an empty line or a potential timing line is seen.
m_state = ignoreBadCue(line);
break;
}
}
}
