/// <summary>
/// Add a using directive.
/// </summary>
/// <param name="compilationUnit">The <see cref="CompilationUnitSyntax"/>.</param>
/// <param name="usingDirective">The <see cref="UsingDirectiveSyntax"/>.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/>.</param>
/// <returns>The updated <see cref="CompilationUnitSyntax"/>.</returns>
public static CompilationUnitSyntax AddUsing(this CompilationUnitSyntax compilationUnit, UsingDirectiveSyntax usingDirective, SemanticModel semanticModel)
{
if (compilationUnit is null)
{
throw new System.ArgumentNullException(nameof(compilationUnit));
}
if (semanticModel is null)
{
throw new System.ArgumentNullException(nameof(semanticModel));
}
if (usingDirective is null)
{
throw new System.ArgumentNullException(nameof(usingDirective));
}
if (compilationUnit.Members.TrySingleOfType <MemberDeclarationSyntax, NamespaceDeclarationSyntax>(out NamespaceDeclarationSyntax? ns) &&
UsingDirectiveComparer.IsSameOrContained(ns, usingDirective))
{
return(compilationUnit);
}
using (var walker = UsingDirectiveWalker.Borrow(compilationUnit))
{
if (walker.UsingDirectives.Count == 0)
{
if (walker.NamespaceDeclarations.TryFirst(out var namespaceDeclaration))
{
if (CodeStyle.UsingDirectivesInsideNamespace(semanticModel) != CodeStyleResult.No)
{
return(compilationUnit.ReplaceNode(namespaceDeclaration, namespaceDeclaration.WithUsings(SyntaxFactory.SingletonList(usingDirective))));
}
return(compilationUnit.ReplaceNode(compilationUnit, compilationUnit.WithUsings(SyntaxFactory.SingletonList(usingDirective))));
}
return(compilationUnit);
}
UsingDirectiveSyntax?previous = null;
foreach (var directive in walker.UsingDirectives)
{
var compare = UsingDirectiveComparer.Compare(directive, usingDirective);
if (compare == 0)
{
return(compilationUnit);
}
if (compare > 0)
{
return(compilationUnit.InsertNodesBefore(directive, new[] { usingDirective.WithTrailingElasticLineFeed() }));
}
previous = directive;
}
return(compilationUnit.InsertNodesAfter(previous, new[] { usingDirective.WithTrailingElasticLineFeed() }));
}
}