/// <summary>
/// Parses the contents of an HTML tag. The current position should be at the first
/// character following the tag's opening less-than character.
///
/// Note: We parse to the end of the tag even if this tag was not requested by the
/// caller. This ensures subsequent parsing takes place after this tag
/// </summary>
/// <param name="reqName">Name of the tag the caller is requesting, or "*" if caller
/// is requesting all tags</param>
/// <param name="tag">Returns information on this tag if it's one the caller is
/// requesting</param>
/// <param name="inScript">Returns true if tag began, and did not end, and script
/// block</param>
/// <returns>True if data is being returned for a tag requested by the caller
/// or false otherwise</returns>
protected bool ParseTag(string reqName, ref HtmlTag tag, out bool inScript)
{
bool doctype, requested;
doctype = inScript = requested = false;
// Get name of this tag
string name = ParseTagName();
// Special handling
if (String.Compare(name, "!DOCTYPE", true) == 0)
doctype = true;
else if (String.Compare(name, "script", true) == 0)
inScript = true;
// Is this a tag requested by caller?
if (reqName == "*" || String.Compare(name, reqName, true) == 0)
{
// Yes
requested = true;
// Create new tag object
tag = new HtmlTag();
tag.Name = name;
tag.Attributes = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
}
// Parse attributes
MovePastWhitespace();
while (Peek() != '>' && Peek() != NullChar)
{
if (Peek() == '/')
{
// Handle trailing forward slash
if (requested)
tag.TrailingSlash = true;
MoveAhead();
MovePastWhitespace();
// If this is a script tag, it was closed
inScript = false;
}
else
{
// Parse attribute name
name = (!doctype) ? ParseAttributeName() : ParseAttributeValue();
MovePastWhitespace();
// Parse attribute value
string value = String.Empty;
if (Peek() == '=')
{
MoveAhead();
MovePastWhitespace();
value = ParseAttributeValue();
MovePastWhitespace();
}
// Add attribute to collection if requested tag
if (requested)
{
// This tag replaces existing tags with same name
if (tag.Attributes.ContainsKey(name))
tag.Attributes.Remove(name);
tag.Attributes.Add(name, value);
}
}
}
// Skip over closing '>'
MoveAhead();
return requested;
}
/// <summary>
/// Parses the next tag that matches the specified tag name
/// </summary>
/// <param name="name">Name of the tags to parse ("*" = parse all tags)</param>
/// <param name="tag">Returns information on the next occurrence of the specified tag or null if none found</param>
/// <returns>True if a tag was parsed or false if the end of the document was reached</returns>
public bool ParseNext(string name, out HtmlTag tag)
{
// Must always set out parameter
tag = null;
// Nothing to do if no tag specified
if (String.IsNullOrEmpty(name))
return false;
// Loop until match is found or no more tags
MoveTo('<');
while (!EndOfText)
{
// Skip over opening '<'
MoveAhead();
// Examine first tag character
char c = Peek();
if (c == '!' && Peek(1) == '-' && Peek(2) == '-')
{
// Skip over comments
const string endComment = "-->";
MoveTo(endComment);
MoveAhead(endComment.Length);
}
else if (c == '/')
{
// Skip over closing tags
MoveTo('>');
MoveAhead();
}
else
{
bool result, inScript;
// Parse tag
result = ParseTag(name, ref tag, out inScript);
// Because scripts may contain tag characters, we have special
// handling to skip over script contents
if (inScript)
MovePastScript();
// Return true if requested tag was found
if (result)
return true;
}
// Find next tag
MoveTo('<');
}
// No more matching tags found
return false;
}