/// <summary>
/// Parses the stream of html tokens starting
/// from the name of top-level element.
/// Returns XmlElement representing the top-level
/// html element
/// </summary>
private XmlElement ParseHtmlContent()
{
// Create artificial root elelemt to be able to group multiple top-level elements
// We create "html" element which may be a duplicate of real HTML element, which is ok, as HtmlConverter will swallow it painlessly..
var htmlRootElement = _document.CreateElement("html", XhtmlNamespace);
OpenStructuringElement(htmlRootElement);
while (_htmlLexicalAnalyzer.NextTokenType != HtmlTokenType.Eof)
{
if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.OpeningTagStart)
{
_htmlLexicalAnalyzer.GetNextTagToken();
if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.Name)
{
var htmlElementName = _htmlLexicalAnalyzer.NextToken.ToLower();
_htmlLexicalAnalyzer.GetNextTagToken();
// Create an element
var htmlElement = _document.CreateElement(htmlElementName, XhtmlNamespace);
// Parse element attributes
ParseAttributes(htmlElement);
if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.EmptyTagEnd ||
HtmlSchema.IsEmptyElement(htmlElementName))
{
// It is an element without content (because of explicit slash or based on implicit knowledge aboout html)
AddEmptyElement(htmlElement);
}
else if (HtmlSchema.IsInlineElement(htmlElementName))
{
// Elements known as formatting are pushed to some special
// pending stack, which allows them to be transferred
// over block tags - by doing this we convert
// overlapping tags into normal heirarchical element structure.
OpenInlineElement(htmlElement);
}
else if (HtmlSchema.IsBlockElement(htmlElementName) ||
HtmlSchema.IsKnownOpenableElement(htmlElementName))
{
// This includes no-scope elements
OpenStructuringElement(htmlElement);
}
}
}
else if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.ClosingTagStart)
{
_htmlLexicalAnalyzer.GetNextTagToken();
if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.Name)
{
var htmlElementName = _htmlLexicalAnalyzer.NextToken.ToLower();
// Skip the name token. Assume that the following token is end of tag,
// but do not check this. If it is not true, we simply ignore one token
// - this is our recovery from bad xml in this case.
_htmlLexicalAnalyzer.GetNextTagToken();
CloseElement(htmlElementName);
}
}
else if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.Text)
{
AddTextContent(_htmlLexicalAnalyzer.NextToken);
}
else if (_htmlLexicalAnalyzer.NextTokenType == HtmlTokenType.Comment)
{
AddComment(_htmlLexicalAnalyzer.NextToken);
}
_htmlLexicalAnalyzer.GetNextContentToken();
}
// Get rid of the artificial root element
if (htmlRootElement.FirstChild is XmlElement &&
htmlRootElement.FirstChild == htmlRootElement.LastChild &&
htmlRootElement.FirstChild.LocalName.ToLower() == "html")
{
htmlRootElement = (XmlElement)htmlRootElement.FirstChild;
}
return(htmlRootElement);
}
// ---------------------------------------------------------------------
//
// Private methods
//
// ---------------------------------------------------------------------
#region Private Methods
/// <summary>
/// Advances a reading position by one character code
/// and reads the next availbale character from a stream.
/// This character becomes available as NextCharacter property.
/// </summary>
/// <remarks>
/// Throws InvalidOperationException if attempted to be called on EndOfStream
/// condition.
/// </remarks>
private void GetNextCharacter()
{
if (_nextCharacterCode == -1)
{
throw new InvalidOperationException("GetNextCharacter method called at the end of a stream");
}
_previousCharacter = NextCharacter;
NextCharacter = _lookAheadCharacter;
_nextCharacterCode = _lookAheadCharacterCode;
// next character not an entity as of now
IsNextCharacterEntity = false;
ReadLookAheadCharacter();
if (NextCharacter == '&')
{
if (_lookAheadCharacter == '#')
{
// numeric entity - parse digits - &#DDDDD;
int entityCode;
entityCode = 0;
ReadLookAheadCharacter();
// largest numeric entity is 7 characters
for (var i = 0; i < 7 && char.IsDigit(_lookAheadCharacter); i++)
{
entityCode = 10 * entityCode + (_lookAheadCharacterCode - '0');
ReadLookAheadCharacter();
}
if (_lookAheadCharacter == ';')
{
// correct format - advance
ReadLookAheadCharacter();
_nextCharacterCode = entityCode;
// if this is out of range it will set the character to '?'
NextCharacter = (char)_nextCharacterCode;
// as far as we are concerned, this is an entity
IsNextCharacterEntity = true;
}
else
{
// not an entity, set next character to the current lookahread character
// we would have eaten up some digits
NextCharacter = _lookAheadCharacter;
_nextCharacterCode = _lookAheadCharacterCode;
ReadLookAheadCharacter();
IsNextCharacterEntity = false;
}
}
else if (char.IsLetter(_lookAheadCharacter))
{
// entity is written as a string
var entity = "";
// maximum length of string entities is 10 characters
for (var i = 0;
i < 10 && (char.IsLetter(_lookAheadCharacter) || char.IsDigit(_lookAheadCharacter));
i++)
{
entity += _lookAheadCharacter;
ReadLookAheadCharacter();
}
if (_lookAheadCharacter == ';')
{
// advance
ReadLookAheadCharacter();
if (HtmlSchema.IsEntity(entity))
{
NextCharacter = HtmlSchema.EntityCharacterValue(entity);
_nextCharacterCode = NextCharacter;
IsNextCharacterEntity = true;
}
else
{
// just skip the whole thing - invalid entity
// move on to the next character
NextCharacter = _lookAheadCharacter;
_nextCharacterCode = _lookAheadCharacterCode;
ReadLookAheadCharacter();
// not an entity
IsNextCharacterEntity = false;
}
}
else
{
// skip whatever we read after the ampersand
// set next character and move on
NextCharacter = _lookAheadCharacter;
ReadLookAheadCharacter();
IsNextCharacterEntity = false;
}
}
}
}