public async Task <AggregatedCompletionContext> GetAggregatedCompletionContextAsync(ITextView textView, CompletionTrigger trigger, SnapshotPoint triggerLocation, CancellationToken token)
{
if (token.IsCancellationRequested || textView.IsClosed)
{
return(AggregatedCompletionContext.Empty);
}
var telemetryHost = GetOrCreateTelemetry(textView);
var telemetry = new CompletionSessionTelemetry(telemetryHost, headless: true);
// ----- GetCompletionSources and GetRootSnapshot need to be run on the UI thread:
await JoinableTaskContext.Factory.SwitchToMainThreadAsync();
if (token.IsCancellationRequested || textView.IsClosed)
{
return(AggregatedCompletionContext.Empty);
}
var rootSnapshot = GetRootSnapshot(textView);
GetCompletionSources(triggerLocation, GetItemSourceProviders, rootSnapshot, textView, textView.BufferGraph, trigger, telemetry, token,
out var sourcesWithLocations, out var applicableToSpan);
// ----- Go back to background thread to continue processing
await TaskScheduler.Default;
if (token.IsCancellationRequested || textView.IsClosed)
{
return(AggregatedCompletionContext.Empty);
}
// No source declared an appropriate ApplicableToSpan
if (applicableToSpan == default)
{
return(AggregatedCompletionContext.Empty);
}
// No source wishes to participate
if (!sourcesWithLocations.Any())
{
return(null);
}
var aggregatingSession = AsyncCompletionSession.CreateAggregatingSession(applicableToSpan, JoinableTaskContext, sourcesWithLocations, this, textView, telemetry, GuardedOperations);
var completionData = await aggregatingSession.ConnectToCompletionSources(trigger, triggerLocation, rootSnapshot, token).ConfigureAwait(true);
if (completionData.IsCanceled)
{
return(AggregatedCompletionContext.Empty);
}
var aggregateCompletionContext = new CompletionContext(
completionData.InitialCompletionItems,
completionData.RequestedSuggestionItemOptions,
completionData.InitialSelectionHint);
return(new AggregatedCompletionContext(aggregateCompletionContext, aggregatingSession));
}
public IAsyncCompletionSession TriggerCompletion(ITextView textView, CompletionTrigger trigger, SnapshotPoint triggerLocation, CancellationToken token)
{
var session = GetSession(textView);
if (session != null)
{
return(session);
}
// This is a simple check that only queries the feature service.
// If it succeeds, we will map triggerLocation to available buffers to discover MEF parts.
// This is expensive but projected languages require it to discover parts in all available buffers.
// To avoid doing this work, call IsCompletionSupported with appropriate IContentType prior to calling TriggerCompletion
if (!CompletionAvailability.IsCurrentlyAvailable(textView))
{
return(null);
}
if (textView.IsClosed)
{
return(null);
}
if (!JoinableTaskContext.IsOnMainThread)
{
throw new InvalidOperationException($"This method must be callled on the UI thread.");
}
var telemetryHost = GetOrCreateTelemetry(textView);
var telemetry = new CompletionSessionTelemetry(telemetryHost);
var rootSnapshot = GetRootSnapshot(textView);
if (token.IsCancellationRequested || textView.IsClosed)
{
return(null);
}
// See if we can use more aggressive cancellation token for typing scenarios
if (trigger.Reason == CompletionTriggerReason.Insertion)
{
token = CompletionUtilities.GetResponsiveToken(textView, token);
}
GetCompletionSources(triggerLocation, GetItemSourceProviders, rootSnapshot, textView, textView.BufferGraph, trigger, telemetry, token,
out var sourcesWithLocations, out var applicableToSpan);
if (token.IsCancellationRequested || textView.IsClosed)
{
return(null);
}
// No source declared an appropriate ApplicableToSpan
if (applicableToSpan == default)
{
return(null);
}
// No source wishes to participate
if (!sourcesWithLocations.Any())
{
return(null);
}
// Some of our extensions need to initialize the source providers before they initialize commit manager providers.
// Therefore, it is important to invoke GetCommitManagerProviders after invoking GetItemSourceProviders.
GetCommitManagersAndChars(triggerLocation, GetCommitManagerProviders, rootSnapshot, textView, telemetry,
out var managersWithBuffers, out var potentialCommitChars);
if (_contentTypeComparer == null)
{
_contentTypeComparer = new StableContentTypeComparer(ContentTypeRegistryService);
}
var itemManager = GetItemManager(triggerLocation, GetItemManagerProviders, rootSnapshot, textView, _contentTypeComparer);
var presenterProvider = GetPresenterProvider(triggerLocation, GetPresenters, rootSnapshot, textView.Roles, _contentTypeComparer);
if (token.IsCancellationRequested || textView.IsClosed)
{
return(null);
}
session = new AsyncCompletionSession(applicableToSpan, potentialCommitChars, JoinableTaskContext, presenterProvider, sourcesWithLocations, managersWithBuffers, itemManager, this, textView, telemetry, GuardedOperations);
textView.Properties.AddProperty(typeof(IAsyncCompletionSession), session);
textView.Closed += DismissSessionOnViewClosed;
EmulateLegacyCompletionTelemetry(textView);
GuardedOperations.RaiseEvent(this, CompletionTriggered, new CompletionTriggeredEventArgs(session, textView));
return(session);
}