public static SignatureHelpSession TryCreate(SnapshotPoint triggerPosition, SignatureHelpTriggerInfo triggerInfo, Lazy <ISignatureHelpBroker> signatureHelpBroker, ITextView textView)
{
var info = SignatureHelpInfo.Create(triggerPosition.Snapshot);
if (info == null)
{
return(null);
}
if (triggerInfo.TriggerReason == SignatureHelpTriggerReason.TypeCharCommand)
{
Debug.Assert(triggerInfo.TriggerCharacter != null);
if (triggerInfo.TriggerCharacter != null && !info.Value.SignatureHelpService.IsTriggerCharacter(triggerInfo.TriggerCharacter.Value))
{
return(null);
}
}
else if (triggerInfo.TriggerReason == SignatureHelpTriggerReason.RetriggerCommand)
{
if (triggerInfo.TriggerCharacter != null && !info.Value.SignatureHelpService.IsRetriggerCharacter(triggerInfo.TriggerCharacter.Value))
{
return(null);
}
}
return(new SignatureHelpSession(info.Value.SignatureHelpService, signatureHelpBroker, textView));
}
bool RestartCore(SnapshotPoint triggerPosition, SignatureHelpTriggerInfo triggerInfo)
{
var info = SignatureHelpInfo.Create(triggerPosition.Snapshot);
if (info == null)
{
return(false);
}
Start(info.Value, triggerPosition, triggerInfo);
return(true);
}
void Start(SignatureHelpInfo info, SnapshotPoint triggerPosition, SignatureHelpTriggerInfo triggerInfo)
{
CancelFetchItems();
Debug.Assert(cancellationTokenSource == null);
cancellationTokenSource = new CancellationTokenSource();
var cancellationTokenSourceTmp = cancellationTokenSource;
StartAsync(info, triggerPosition, triggerInfo, cancellationTokenSource.Token)
.ContinueWith(t => {
var ex = t.Exception;
// Free resources
if (cancellationTokenSource == cancellationTokenSourceTmp)
{
CancelFetchItems();
}
}, CancellationToken.None, TaskContinuationOptions.None, TaskScheduler.FromCurrentSynchronizationContext());
}
async Task StartAsync(SignatureHelpInfo info, SnapshotPoint triggerPosition, SignatureHelpTriggerInfo triggerInfo, CancellationToken cancellationToken)
{
// This helps a little to speed up the code
ProfileOptimizationHelper.StartProfile("roslyn-sighelp-" + info.SignatureHelpService.Language);
var result = await info.SignatureHelpService.GetItemsAsync(info.Document, triggerPosition.Position, triggerInfo, cancellationToken);
if (result == null)
{
Dispose();
return;
}
if (cancellationToken.IsCancellationRequested)
{
return;
}
StartSession(triggerPosition, result);
}
