blob: de886e77ee54aaa0d087dc82b98b4d2dec537d96 [file] [log] [blame]
// Copyright (c) 2018, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
import 'package:analysis_server/lsp_protocol/protocol_special.dart';
import 'package:analysis_server/src/computer/computer_signature.dart';
import 'package:analysis_server/src/lsp/handlers/handlers.dart';
import 'package:analysis_server/src/lsp/lsp_analysis_server.dart';
import 'package:analysis_server/src/lsp/mapping.dart';
class SignatureHelpHandler
extends MessageHandler<SignatureHelpParams, SignatureHelp> {
SignatureHelpHandler(LspAnalysisServer server) : super(server);
Method get handlesMessage => Method.textDocument_signatureHelp;
LspJsonHandler<SignatureHelpParams> get jsonHandler =>
Future<ErrorOr<SignatureHelp>> handle(
SignatureHelpParams params, CancellationToken token) async {
if (!isDartDocument(params.textDocument)) {
return success(null);
// If triggered automatically by pressing the trigger character, we will
// only provide results if the character we typed was the one that actually
// starts the argument list. This is to avoid popping open signature help
// whenever the user types a `(` that might not be the start of an argument
// list, as the client does not have any context and will always send the
// request.
final autoTriggered = params.context?.triggerKind ==
SignatureHelpTriggerKind.TriggerCharacter &&
// Retriggers can be ignored (treated as manual invocations) as it's
// fine to always generate results if the signature help is already
// visible on the client (it will just update, it doesn't pop up new UI).
params.context?.isRetrigger == false;
final pos = params.position;
final path = pathOfDoc(params.textDocument);
final unit = await path.mapResult(requireResolvedUnit);
final offset = await unit.mapResult((unit) => toOffset(unit.lineInfo, pos));
return offset.mapResult((offset) {
final computer = DartUnitSignatureComputer(
if (!computer.offsetIsValid) {
return success(); // No error, just no valid hover.
final signature = computer.compute();
if (signature == null) {
return success(); // No error, just no valid hover.
// Skip results if this was an auto-trigger but not from the start of the
// argument list.
// The ArgumentList's offset is before the paren, but the request offset
// will be after.
if (autoTriggered &&
computer.argumentList != null &&
offset != computer.argumentList.offset + 1) {
return success();
final formats = server?.clientCapabilities?.textDocument?.signatureHelp
return success(toSignatureHelp(formats, signature));