/// <summary>
/// If there was no $end$ token, place it at the end of the snippet code. Otherwise, it
/// defaults to the beginning of the snippet code.
/// </summary>
private static bool SetEndPositionIfNoneSpecified(IExpansionSession pSession)
{
if (pSession.GetSnippetNode() is not XElement snippetNode)
{
return(false);
}
var ns = snippetNode.Name.NamespaceName;
var codeNode = snippetNode.Element(XName.Get("Code", ns));
if (codeNode == null)
{
return(false);
}
var delimiterAttribute = codeNode.Attribute("Delimiter");
var delimiter = delimiterAttribute != null ? delimiterAttribute.Value : "$";
if (codeNode.Value.IndexOf(string.Format("{0}end{0}", delimiter), StringComparison.OrdinalIgnoreCase) != -1)
{
return(false);
}
var snippetSpan = pSession.GetSnippetSpan();
var newEndSpan = new SnapshotSpan(snippetSpan.End, 0);
pSession.EndSpan = newEndSpan;
return(true);
}
public void FormatSpan(SnapshotSpan span)
{
// Formatting a snippet isn't cancellable.
var cancellationToken = CancellationToken.None;
// At this point, the $selection$ token has been replaced with the selected text and
// declarations have been replaced with their default text. We need to format the
// inserted snippet text while carefully handling $end$ position (where the caret goes
// after Return is pressed). The IExpansionSession keeps a tracking point for this
// position but we do the tracking ourselves to properly deal with virtual space. To
// ensure the end location is correct, we take three extra steps:
// 1. Insert an empty comment ("/**/" or "'") at the current $end$ position (prior
// to formatting), and keep a tracking span for the comment.
// 2. After formatting the new snippet text, find and delete the empty multiline
// comment (via the tracking span) and notify the IExpansionSession of the new
// $end$ location. If the line then contains only whitespace (due to the formatter
// putting the empty comment on its own line), then delete the white space and
// remember the indentation depth for that line.
// 3. When the snippet is finally completed (via Return), and PositionCaretForEditing()
// is called, check to see if the end location was on a line containing only white
// space in the previous step. If so, and if that line is still empty, then position
// the caret in virtual space.
// This technique ensures that a snippet like "if($condition$) { $end$ }" will end up
// as:
// if ($condition$)
// {
// $end$
// }
if (!TryGetSubjectBufferSpan(span, out var snippetSpan))
{
return;
}
// Insert empty comment and track end position
var snippetTrackingSpan = snippetSpan.CreateTrackingSpan(SpanTrackingMode.EdgeInclusive);
var fullSnippetSpan = ExpansionSession.GetSnippetSpan();
var isFullSnippetFormat = fullSnippetSpan == span;
var endPositionTrackingSpan = isFullSnippetFormat ? InsertEmptyCommentAndGetEndPositionTrackingSpan() : null;
var formattingSpan = CommonFormattingHelpers.GetFormattingSpan(SubjectBuffer.CurrentSnapshot, snippetTrackingSpan.GetSpan(SubjectBuffer.CurrentSnapshot));
SubjectBuffer.CurrentSnapshot.FormatAndApplyToBuffer(formattingSpan, CancellationToken.None);
if (isFullSnippetFormat)
{
CleanUpEndLocation(endPositionTrackingSpan);
// Unfortunately, this is the only place we can safely add references and imports
// specified in the snippet xml. In OnBeforeInsertion we have no guarantee that the
// snippet xml will be available, and changing the buffer during OnAfterInsertion can
// cause the underlying tracking spans to get out of sync.
var currentStartPosition = snippetTrackingSpan.GetStartPoint(SubjectBuffer.CurrentSnapshot).Position;
AddReferencesAndImports(
ExpansionSession, currentStartPosition, cancellationToken);
SetNewEndPosition(endPositionTrackingSpan);
}
}
