private static Task<Document> GetTransformedDocumentAsync(Document document, SyntaxNode syntaxRoot, CancellationToken cancellationToken)
{
var compilationUnit = (CompilationUnitSyntax)syntaxRoot;
var indentationOptions = IndentationOptions.FromDocument(document);
var usingsHelper = new UsingsHelper(compilationUnit);
var namespaceCount = CountNamespaces(compilationUnit.Members);
// Only move using declarations inside the namespace when
// - SA1200 is enabled
// - There are no global attributes
// - There is only a single namespace declared at the top level
var moveInsideNamespace =
!document.IsAnalyzerSuppressed(SA1200UsingDirectivesMustBePlacedWithinNamespace.DiagnosticId)
&& !compilationUnit.AttributeLists.Any()
&& compilationUnit.Members.Count == 1
&& namespaceCount == 1;
string usingsIndentation;
if (moveInsideNamespace)
{
var rootNamespace = compilationUnit.Members.OfType<NamespaceDeclarationSyntax>().First();
var indentationLevel = IndentationHelper.GetIndentationSteps(indentationOptions, rootNamespace);
usingsIndentation = IndentationHelper.GenerateIndentationString(indentationOptions, indentationLevel + 1);
}
else
{
usingsIndentation = string.Empty;
}
// - The strategy is to strip all using directive that are not inside a conditional directive and replace them later with a sorted list at the correct spot
// - The using directives that are inside a conditional directive are replaced (in sorted order) on the spot.
// - Conditional directives are not moved, as correctly parsing them is too tricky
// - No using directives will be stripped when there are multiple namespaces. In that case everything is replaced on the spot.
List<UsingDirectiveSyntax> stripList;
var replaceMap = new Dictionary<UsingDirectiveSyntax, UsingDirectiveSyntax>();
// When there are multiple namespaces, do not move using statements outside of them, only sort.
if (namespaceCount > 1)
{
BuildReplaceMapForNamespaces(usingsHelper, replaceMap, indentationOptions);
stripList = new List<UsingDirectiveSyntax>();
}
else
{
stripList = usingsHelper.GetContainedUsings(usingsHelper.RootSpan);
}
BuildReplaceMapForConditionalDirectives(usingsHelper, replaceMap, indentationOptions, usingsHelper.RootSpan);
var usingSyntaxRewriter = new UsingSyntaxRewriter(stripList, replaceMap);
var newSyntaxRoot = usingSyntaxRewriter.Visit(syntaxRoot);
if (moveInsideNamespace)
{
newSyntaxRoot = AddUsingsToNamespace(newSyntaxRoot, usingsHelper, usingsIndentation, replaceMap.Any());
}
else if (namespaceCount <= 1)
{
newSyntaxRoot = AddUsingsToCompilationRoot(newSyntaxRoot, usingsHelper, usingsIndentation, replaceMap.Any());
}
newSyntaxRoot = ReAddFileHeader(syntaxRoot, newSyntaxRoot);
var newDocument = document.WithSyntaxRoot(newSyntaxRoot.WithoutFormatting());
return Task.FromResult(newDocument);
}
public UsingsHelper(Document document, CompilationUnitSyntax compilationUnit)
{
this.conditionalDirectiveTree = DirectiveSpan.BuildConditionalDirectiveTree(compilationUnit);
this.separateSystemDirectives = !document.IsAnalyzerSuppressed(SA1208SystemUsingDirectivesMustBePlacedBeforeOtherUsingDirectives.DiagnosticId);
this.ProcessUsingDirectives(compilationUnit.Usings);
this.ProcessMembers(compilationUnit.Members);
}