internal SnapshotSpan?GetExpressionAtPointWorker(SnapshotSpan span, GetExpressionOptions options)
{
// First do some very quick tokenization to save a full analysis
if (!IsPossibleExpressionAtPoint(span.Start))
{
return(null);
}
if (span.End.GetContainingLine() != span.Start.GetContainingLine() &&
!IsPossibleExpressionAtPoint(span.End))
{
return(null);
}
var sourceSpan = new SnapshotSpanSourceCodeReader(
new SnapshotSpan(span.Snapshot, 0, span.End.Position)
);
PythonAst ast;
using (var parser = Parser.CreateParser(sourceSpan, LanguageVersion)) {
ast = parser.ParseFile();
}
var finder = new ExpressionFinder(ast, options);
var actualExpr = finder.GetExpressionSpan(span.ToSourceSpan());
return(actualExpr?.ToSnapshotSpan(span.Snapshot));
}
/// <summary>
/// Gets the smallest expression that fully contains the span.
/// </summary>
/// <remarks>
/// When options specifies the member target, rather than the
/// full expression, only the start of the span is used.
/// </remarks>
public SnapshotSpan?GetExpressionAtPoint(SnapshotSpan span, GetExpressionOptions options)
{
var timer = new Stopwatch();
timer.Start();
bool hasError = true, hasResult = false;
try {
var r = GetExpressionAtPointWorker(span, options);
hasResult = r != null;
hasError = false;
return(r);
} finally {
timer.Stop();
try {
int elapsed = (int)Math.Min(timer.ElapsedMilliseconds, int.MaxValue);
if (elapsed > 10)
{
Services.Python.Logger.LogEvent(Logging.PythonLogEvent.GetExpressionAtPoint, new Logging.GetExpressionAtPointInfo {
Milliseconds = elapsed,
PartialAstLength = span.End.Position,
ExpressionFound = hasResult,
Success = !hasError
});
}
} catch (Exception ex) {
Debug.Fail(ex.ToUnhandledExceptionMessage(GetType()));
}
}
}
private static PythonAstAndSource Parse(string code, GetExpressionOptions options)
{
code += "\n";
var parser = Parser.CreateParser(new StringReader(code), PythonLanguageVersion.V35, new ParserOptions {
Verbatim = true
});
return(new PythonAstAndSource {
Ast = parser.ParseFile(), Source = code, Options = options
});
}
