/// <summary>Calculates the position, the caret should be set to, after the
/// code fix was applied.</summary>
/// <param name="changedSolution">The changed solution (code fix applied).</param>
/// <param name="originalDocument">The original document (code fix not applied).</param>
/// <param name="diagnostic">The diagnosted code fix.</param>
/// <param name="cancellationToken">A cancellation token to cancel the calculation.</param>
/// <returns>The position , the caret should be set to, after the code fix
/// was applied. Null if the caret should not be moved.</returns>
private static async Task <NavigationTarget> CalculateNavigationTarget(Solution changedSolution, Document originalDocument, Diagnostic diagnostic, CancellationToken cancellationToken)
{
MemberDeclarationSyntax originalDeclaration;
MemberDeclarationSyntax changedDeclaration;
SyntaxNode originalSyntaxRoot;
SyntaxNode changedSyntaxRoot;
Document changedDocument;
int targetPosition;
NavigationTarget result = null;
// Get syntax root of the original document
originalSyntaxRoot = await originalDocument.GetSyntaxRootAsync(cancellationToken)
.ConfigureAwait(false);
// Get the original declaration that was diagnosted
originalDeclaration = originalSyntaxRoot.FindToken(diagnostic.Location.SourceSpan.Start)
.Parent
.AncestorsAndSelf()
.OfType <MemberDeclarationSyntax>()
.First();
// Get the changed document
changedDocument = changedSolution.GetDocument(originalDocument.Id);
// Get syntax root of the changed document
changedSyntaxRoot = await changedDocument.GetSyntaxRootAsync(cancellationToken)
.ConfigureAwait(false);
// Find declaration in changed document
changedDeclaration = changedSyntaxRoot.DescendantNodes()
.OfType <MemberDeclarationSyntax>()
.FirstOrDefault(newNode => SyntaxFactory.AreEquivalent(newNode, originalDeclaration));
// Get the target position in the the XML documentation header of the
// changed declaration inside the changed document
targetPosition = DocumentationHelper.GetPositionOfFirstEmptyDocumentationTag(changedDeclaration);
// targetPosition is less than zero if no empty documentation tag was found.
if (targetPosition > 0)
{
result = new NavigationTarget(changedDocument.Id, targetPosition);
}
return(result);
}
