private void AddImportTags(ISmartTagSession session, IList<SmartTagActionSet> smartTagActionSets) {
var textBuffer = _textBuffer;
var span = session.CreateTrackingSpan(textBuffer);
var imports = textBuffer.CurrentSnapshot.GetMissingImports(_serviceProvider, span);
if (imports == MissingImportAnalysis.Empty) {
return;
}
SmartTagController controller;
session.Properties.TryGetProperty<SmartTagController>(typeof(SmartTagController), out controller);
if (controller == null) {
return;
}
var task = Volatile.Read(ref controller._curTask);
var origTask = task;
var snapshot = textBuffer.CurrentSnapshot;
if (task != null &&
task.ApplicableToSpan.GetSpan(snapshot) != imports.ApplicableToSpan.GetSpan(snapshot)) {
// Previous task is invalid, so abort it and we'll start a
// new one.
task.Abort();
session.Properties.RemoveProperty(typeof(SmartTagAugmentTask));
task = null;
}
if (task == null) {
task = new SmartTagAugmentTask(
_serviceProvider,
textBuffer,
session.TextView,
imports
);
if (Interlocked.CompareExchange(ref controller._curTask, task, origTask) != origTask) {
// Item has been changed by someone else, so abort
// Except we should always be on the UI thread here, so
// there should be no races.
Debug.Fail("Race in AugmentSmartTagSession");
return;
}
}
session.ApplicableToSpan = imports.ApplicableToSpan;
var result = task.GetResultIfComplete();
if (result != null && Interlocked.CompareExchange(ref controller._curTask, null, task) == task) {
// Provide results if we were the current task and we are
// now complete
smartTagActionSets.Add(result);
}
}