public async Task <LSP.CompletionList?> HandleRequestAsync(LSP.CompletionParams request, RequestContext context, CancellationToken cancellationToken)
{
var document = context.Document;
if (document == null)
{
return(null);
}
// C# and VB share the same LSP language server, and thus share the same default trigger characters.
// We need to ensure the trigger character is valid in the document's language. For example, the '{'
// character, while a trigger character in VB, is not a trigger character in C#.
var triggerCharacter = char.Parse(request.Context.TriggerCharacter);
if (request.Context.TriggerKind == LSP.CompletionTriggerKind.TriggerCharacter && !char.IsLetterOrDigit(triggerCharacter) &&
!IsValidTriggerCharacterForDocument(document, request.Context.TriggerCharacter))
{
return(null);
}
var position = await document.GetPositionFromLinePositionAsync(ProtocolConversions.PositionToLinePosition(request.Position), cancellationToken).ConfigureAwait(false);
// Filter out snippets as they are not supported in the LSP client
// https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1139740
// Filter out unimported types for now as there are two issues with providing them:
// 1. LSP client does not currently provide a way to provide detail text on the completion item to show the namespace.
// https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1076759
// 2. We need to figure out how to provide the text edits along with the completion item or provide them in the resolve request.
// https://devdiv.visualstudio.com/DevDiv/_workitems/edit/985860/
// 3. LSP client should support completion filters / expanders
var documentOptions = await document.GetOptionsAsync(cancellationToken).ConfigureAwait(false);
var completionOptions = documentOptions
.WithChangedOption(CompletionOptions.SnippetsBehavior, SnippetsRule.NeverInclude)
.WithChangedOption(CompletionOptions.ShowItemsFromUnimportedNamespaces, false)
.WithChangedOption(CompletionServiceOptions.IsExpandedCompletion, false)
.WithChangedOption(CompletionServiceOptions.DisallowAddingImports, true);
var completionService = document.Project.LanguageServices.GetRequiredService <CompletionService>();
// TO-DO: More LSP.CompletionTriggerKind mappings are required to properly map to Roslyn CompletionTriggerKinds.
// https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1178726
var triggerKind = ProtocolConversions.LSPToRoslynCompletionTriggerKind(request.Context.TriggerKind);
var completionTrigger = new CompletionTrigger(triggerKind, triggerCharacter);
var list = await completionService.GetCompletionsAsync(document, position, completionTrigger, options : completionOptions, cancellationToken : cancellationToken).ConfigureAwait(false);
if (list == null)
{
return(null);
}
var lspVSClientCapability = context.ClientCapabilities?.HasVisualStudioLspCapability() == true;
var commitCharactersRuleCache = new Dictionary <ImmutableArray <CharacterSetModificationRule>, ImmutableArray <string> >();
return(new LSP.VSCompletionList
{
Items = list.Items.Select(item => CreateLSPCompletionItem(request, item, lspVSClientCapability, completionTrigger, commitCharactersRuleCache)).ToArray(),
SuggesstionMode = list.SuggestionModeItem != null,
});
// Local functions
bool IsValidTriggerCharacterForDocument(Document document, string triggerCharacter)
{
if (document.Project.Language == LanguageNames.CSharp)
{
return(_csharpTriggerCharacters.Contains(triggerCharacter));
}
else if (document.Project.Language == LanguageNames.VisualBasic)
{
return(_vbTriggerCharacters.Contains(triggerCharacter));
}
// Typescript still calls into this for completion.
// Since we don't know what their trigger characters are, just return true.
return(true);
}
