public CSharpMethodExtractor(CSharpSelectionResult result) :
base(result)
{
}
public override async Task <SelectionResult> GetValidSelectionAsync(CancellationToken cancellationToken)
{
if (!this.ContainsValidSelection)
{
return(NullSelection);
}
var text = this.SemanticDocument.Text;
var root = this.SemanticDocument.Root;
var model = this.SemanticDocument.SemanticModel;
var doc = this.SemanticDocument;
// go through pipe line and calculate information about the user selection
var selectionInfo = GetInitialSelectionInfo(root, text, cancellationToken);
selectionInfo = AssignInitialFinalTokens(selectionInfo, root, cancellationToken);
selectionInfo = AdjustFinalTokensBasedOnContext(selectionInfo, model, cancellationToken);
selectionInfo = AssignFinalSpan(selectionInfo, text, cancellationToken);
selectionInfo = ApplySpecialCases(selectionInfo, text, cancellationToken);
selectionInfo = CheckErrorCasesAndAppendDescriptions(selectionInfo, root, model, cancellationToken);
// there was a fatal error that we couldn't even do negative preview, return error result
if (selectionInfo.Status.FailedWithNoBestEffortSuggestion())
{
return(new ErrorSelectionResult(selectionInfo.Status));
}
var controlFlowSpan = GetControlFlowSpan(selectionInfo);
if (!selectionInfo.SelectionInExpression)
{
var statementRange = GetStatementRangeContainedInSpan <StatementSyntax>(root, controlFlowSpan, cancellationToken);
if (statementRange == null)
{
selectionInfo = selectionInfo.WithStatus(s => s.With(OperationStatusFlag.None, CSharpFeaturesResources.Can_t_determine_valid_range_of_statements_to_extract));
return(new ErrorSelectionResult(selectionInfo.Status));
}
var isFinalSpanSemanticallyValid = IsFinalSpanSemanticallyValidSpan(model, controlFlowSpan, statementRange, cancellationToken);
if (!isFinalSpanSemanticallyValid)
{
// check control flow only if we are extracting statement level, not expression
// level. you can not have goto that moves control out of scope in expression level
// (even in lambda)
selectionInfo = selectionInfo.WithStatus(s => s.With(OperationStatusFlag.BestEffort, CSharpFeaturesResources.Not_all_code_paths_return));
}
}
// Warn if local functions are in selection since data flow analysis
// cannot correctly analyze them
// https://github.com/dotnet/roslyn/issues/14214
if (SpanInvolvesLocalFunction(selectionInfo.FinalSpan, model, root))
{
selectionInfo = selectionInfo.WithStatus(s => s.With(
OperationStatusFlag.Succeeded | OperationStatusFlag.BestEffort,
CSharpFeaturesResources.Warning_Extracting_a_local_function_reference_may_produce_invalid_code));
var commonRoot = selectionInfo.CommonRootFromOriginalSpan;
var annotated = commonRoot.WithAdditionalAnnotations(
WarningAnnotation.Create(CSharpFeaturesResources.Warning_Extracting_a_local_function_reference_may_produce_invalid_code));
doc = await doc.WithSyntaxRootAsync(
root.ReplaceNode(commonRoot, annotated),
cancellationToken).ConfigureAwait(false);
selectionInfo.FirstTokenInOriginalSpan = doc.Root.FindToken(selectionInfo.FirstTokenInOriginalSpan.SpanStart);
selectionInfo.LastTokenInOriginalSpan = doc.Root.FindToken(selectionInfo.LastTokenInOriginalSpan.SpanStart);
selectionInfo.FirstTokenInFinalSpan = doc.Root.FindToken(selectionInfo.FirstTokenInFinalSpan.SpanStart);
selectionInfo.LastTokenInFinalSpan = doc.Root.FindToken(selectionInfo.LastTokenInFinalSpan.SpanStart);
}
return(await CSharpSelectionResult.CreateAsync(
selectionInfo.Status,
selectionInfo.OriginalSpan,
selectionInfo.FinalSpan,
this.Options,
selectionInfo.SelectionInExpression,
doc,
selectionInfo.FirstTokenInFinalSpan,
selectionInfo.LastTokenInFinalSpan,
cancellationToken).ConfigureAwait(false));
}