private static void AddTagDirectives(TagDirectiveCollection directives, IEnumerable <TagDirective> source)
{
foreach (var directive in source)
{
if (!directives.Contains(directive))
{
directives.Add(directive);
}
}
}
/// <summary>
/// Parse directives.
/// </summary>
private VersionDirective ProcessDirectives(TagDirectiveCollection tags)
{
VersionDirective version = null;
bool hasOwnDirectives = false;
while (true)
{
VersionDirective currentVersion;
TagDirective tag;
if ((currentVersion = GetCurrentToken() as VersionDirective) != null)
{
if (version != null)
{
throw new SemanticErrorException(currentVersion.Start, currentVersion.End, "Found duplicate %YAML directive.");
}
if (currentVersion.Version.Major != Constants.MajorVersion || currentVersion.Version.Minor != Constants.MinorVersion)
{
throw new SemanticErrorException(currentVersion.Start, currentVersion.End, "Found incompatible YAML document.");
}
version = currentVersion;
hasOwnDirectives = true;
}
else if ((tag = GetCurrentToken() as TagDirective) != null)
{
if (tags.Contains(tag.Handle))
{
throw new SemanticErrorException(tag.Start, tag.End, "Found duplicate %TAG directive.");
}
tags.Add(tag);
hasOwnDirectives = true;
}
else
{
break;
}
Skip();
}
AddTagDirectives(tags, Constants.DefaultTagDirectives);
if (hasOwnDirectives)
{
tagDirectives.Clear();
}
AddTagDirectives(tagDirectives, tags);
return(version);
}
/// <summary>
/// Parse the productions:
/// implicit_document ::= block_node DOCUMENT-END*
/// *
/// explicit_document ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
/// *************************
/// </summary>
private ParsingEvent ParseDocumentStart(bool isImplicit)
{
// Parse extra document end indicators.
if (!isImplicit)
{
while (GetCurrentToken() is DocumentEnd)
{
Skip();
}
}
// Parse an isImplicit document.
if (isImplicit && !(GetCurrentToken() is VersionDirective || GetCurrentToken() is TagDirective || GetCurrentToken() is DocumentStart || GetCurrentToken() is StreamEnd))
{
var directives = new TagDirectiveCollection();
ProcessDirectives(directives);
states.Push(ParserState.DocumentEnd);
state = ParserState.BlockNode;
return(new Events.DocumentStart(null, directives, true, GetCurrentToken().Start, GetCurrentToken().End));
}
// Parse an explicit document.
else if (!(GetCurrentToken() is StreamEnd))
{
Mark start = GetCurrentToken().Start;
var directives = new TagDirectiveCollection();
var versionDirective = ProcessDirectives(directives);
var current = GetCurrentToken();
if (!(current is DocumentStart))
{
throw new SemanticErrorException(current.Start, current.End, "Did not find expected <document start>.");
}
states.Push(ParserState.DocumentEnd);
state = ParserState.DocumentContent;
ParsingEvent evt = new Events.DocumentStart(versionDirective, directives, false, start, current.End);
Skip();
return(evt);
}
// Parse the stream end.
else
{
state = ParserState.StreamEnd;
ParsingEvent evt = new Events.StreamEnd(GetCurrentToken().Start, GetCurrentToken().End);
// Do not call skip here because that would throw an exception
if (scanner.MoveNextWithoutConsuming())
{
throw new InvalidOperationException("The scanner should contain no more tokens.");
}
return(evt);
}
}
