private void LexBlock(SnapshotSpan span, TrackedBlock block, bool cache)
{
this.InvalidateBlockEdge(span, block);
block.ClearCache();
block.Version = span.Snapshot.Version;
Span textSpan = block.Block.GetSpan(span.Snapshot);
string text = span.Snapshot.GetText(textSpan);
this.lexer.Reset();
this.lexer.SetInputStream(new AntlrInputStream(text));
if (block.StartState == null)
{
block.StartState = this.SaveLexerState();
}
else
{
block.StartState.Restore(this.lexer);
}
IToken token = null;
int tokenType = -1;
int startPosition = textSpan.Start;
int endPosition = startPosition;
int blockEnd = startPosition + BlockSize;
do
{
LexerState state = this.SaveLexerState();
token = lexer.NextToken();
if (lexer._hitEOF)
{
tokenType = -1;
endPosition = textSpan.End;
}
else if (token != null)
{
tokenType = token.Type;
endPosition += token.StopIndex - token.StartIndex + 1;
}
if (token == null || tokenType < 0)
{
int textLength = endPosition - startPosition;
int delta = 0;
tokenType = -1;
while (tokenType < 0 && startPosition + textLength < span.Snapshot.Length)
{
delta += 1024;
textLength += Math.Min(span.Snapshot.Length - startPosition - textLength, delta);
string currentText = span.Snapshot.GetText(startPosition, textLength);
textLength = currentText.Length;
this.lexer.Reset();
this.lexer.SetInputStream(new AntlrInputStream(currentText));
state.Restore(this.lexer);
token = lexer.NextToken();
if (lexer._hitEOF)
{
endPosition = startPosition + textLength;
}
else if (token != null)
{
tokenType = token.Type;
endPosition = startPosition + token.StopIndex - token.StartIndex + 1;
}
else
{
endPosition = startPosition + textLength;
}
}
}
if (cache)
{
var classification = this.GetClassificationType(tokenType, this.lexer._mode);
var tokenSpan = this.CreateSnapshotSpan(span, startPosition, endPosition);
var classificationSpan = new ClassificationSpan(tokenSpan, classification);
block.CacheClassification(classificationSpan);
}
startPosition = endPosition;
}while (token != null && startPosition < textSpan.End && startPosition < blockEnd);
Span blockSpan = Span.FromBounds(textSpan.Start, endPosition);
block.Block = span.Snapshot.CreateTrackingSpan(blockSpan, textSpan.Start == 0 ? SpanTrackingMode.EdgeInclusive : SpanTrackingMode.EdgePositive);
block.EndState = this.SaveLexerState();
this.InvalidateBlockEdge(span, block);
}
protected virtual LexerState SaveLexerState()
{
LexerState state = new LexerState(this.lexer);
return(state);
}
