/// <summary>
/// Parses the link target.
/// For reference link definition, this is the bit after "[id]: thisbit"
/// For inline link, this is the bit in the parens: [link text](thisbit)
/// </summary>
/// <param name="p">The p.</param>
/// <param name="id">The identifier.</param>
/// <param name="ExtraMode">if set to <c>true</c> [extra mode].</param>
/// <returns>LinkDefinition.</returns>
internal static LinkDefinition ParseLinkTarget(StringScanner p, string id, bool ExtraMode)
{
// Skip whitespace
p.SkipWhitespace();
// End of string?
if (p.eol)
{
return(null);
}
// Create the link definition
var r = new LinkDefinition(id);
// Is the url enclosed in angle brackets
if (p.SkipChar('<'))
{
// Extract the url
p.Mark();
// Find end of the url
while (p.current != '>')
{
if (p.eof)
{
return(null);
}
p.SkipEscapableChar(ExtraMode);
}
string url = p.Extract();
if (!p.SkipChar('>'))
{
return(null);
}
// Unescape it
r.url = Utils.UnescapeString(url.Trim(), ExtraMode);
// Skip whitespace
p.SkipWhitespace();
}
else
{
// Find end of the url
p.Mark();
int paren_depth = 1;
while (!p.eol)
{
char ch = p.current;
if (char.IsWhiteSpace(ch))
{
break;
}
if (id == null)
{
if (ch == '(')
{
paren_depth++;
}
else if (ch == ')')
{
paren_depth--;
if (paren_depth == 0)
{
break;
}
}
}
p.SkipEscapableChar(ExtraMode);
}
r.url = Utils.UnescapeString(p.Extract().Trim(), ExtraMode);
}
p.SkipLinespace();
// End of inline target
if (p.DoesMatch(')'))
{
return(r);
}
bool bOnNewLine = p.eol;
int posLineEnd = p.position;
if (p.eol)
{
p.SkipEol();
p.SkipLinespace();
}
// Work out what the title is delimited with
char delim;
switch (p.current)
{
case '\'':
case '\"':
delim = p.current;
break;
case '(':
delim = ')';
break;
default:
if (bOnNewLine)
{
p.position = posLineEnd;
return(r);
}
else
{
return(null);
}
}
// Skip the opening title delimiter
p.SkipForward(1);
// Find the end of the title
p.Mark();
while (true)
{
if (p.eol)
{
return(null);
}
if (p.current == delim)
{
if (delim != ')')
{
int savepos = p.position;
// Check for embedded quotes in title
// Skip the quote and any trailing whitespace
p.SkipForward(1);
p.SkipLinespace();
// Next we expect either the end of the line for a link definition
// or the close bracket for an inline link
if ((id == null && p.current != ')') ||
(id != null && !p.eol))
{
continue;
}
p.position = savepos;
}
// End of title
break;
}
p.SkipEscapableChar(ExtraMode);
}
// Store the title
r.title = Utils.UnescapeString(p.Extract(), ExtraMode);
// Skip closing quote
p.SkipForward(1);
// Done!
return(r);
}
// Process [link] and ![image] directives
Token ProcessLinkOrImageOrFootnote()
{
// Link or image?
TokenType token_type = SkipChar('!') ? TokenType.img : TokenType.link;
// Opening '['
if (!SkipChar('['))
{
return(null);
}
// Is it a foonote?
var savepos = position;
if (m_Markdown.ExtraMode && token_type == TokenType.link && SkipChar('^'))
{
SkipLinespace();
// Parse it
string id;
if (SkipFootnoteID(out id) && SkipChar(']'))
{
// Look it up and create footnote reference token
int footnote_index = m_Markdown.ClaimFootnote(id);
if (footnote_index >= 0)
{
// Yes it's a footnote
return(CreateToken(TokenType.footnote, new FootnoteReference(footnote_index, id)));
}
}
// Rewind
position = savepos;
}
if (DisableLinks && token_type == TokenType.link)
{
return(null);
}
bool ExtraMode = m_Markdown.ExtraMode;
// Find the closing square bracket, allowing for nesting, watching for
// escapable characters
Mark();
int depth = 1;
while (!eof)
{
char ch = current;
if (ch == '[')
{
depth++;
}
else if (ch == ']')
{
depth--;
if (depth == 0)
{
break;
}
}
this.SkipEscapableChar(ExtraMode);
}
// Quit if end
if (eof)
{
return(null);
}
// Get the link text and unescape it
string link_text = Utils.UnescapeString(Extract(), ExtraMode);
// The closing ']'
SkipForward(1);
// Save position in case we need to rewind
savepos = position;
// Inline links must follow immediately
if (SkipChar('('))
{
// Extract the url and title
var link_def = LinkDefinition.ParseLinkTarget(this, null, m_Markdown.ExtraMode);
if (link_def == null)
{
return(null);
}
// Closing ')'
SkipWhitespace();
if (!SkipChar(')'))
{
return(null);
}
// Create the token
return(CreateToken(token_type, new LinkInfo(link_def, link_text)));
}
// Optional space or tab
if (!SkipChar(' '))
{
SkipChar('\t');
}
// If there's line end, we're allow it and as must line space as we want
// before the link id.
if (eol)
{
SkipEol();
SkipLinespace();
}
// Reference link?
string link_id = null;
if (current == '[')
{
// Skip the opening '['
SkipForward(1);
// Find the start/end of the id
Mark();
if (!Find(']'))
{
return(null);
}
// Extract the id
link_id = Extract();
// Skip closing ']'
SkipForward(1);
}
else
{
// Rewind to just after the closing ']'
position = savepos;
}
// Link id not specified?
if (string.IsNullOrEmpty(link_id))
{
// Use the link text (implicit reference link)
link_id = Utils.NormalizeLineEnds(link_text);
// If the link text has carriage returns, normalize
// to spaces
if (!object.ReferenceEquals(link_id, link_text))
{
while (link_id.Contains(" \n"))
{
link_id = link_id.Replace(" \n", "\n");
}
link_id = link_id.Replace("\n", " ");
}
}
// Find the link definition abort if not defined
var def = m_Markdown.GetLinkDefinition(link_id);
if (def == null)
{
return(null);
}
// Create a token
return(CreateToken(token_type, new LinkInfo(def, link_text)));
}
// Add a link definition
internal void AddLinkDefinition(LinkDefinition link)
{
// Store it
m_LinkDefinitions[link.id] = link;
}
/// <summary>
/// Initializes a new instance of the <see cref="LinkInfo"/> class.
/// </summary>
/// <param name="def">The definition.</param>
/// <param name="link_text">The link text.</param>
public LinkInfo(LinkDefinition def, string link_text)
{
this.def = def;
this.link_text = link_text;
}