| // Copyright 2018 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package server |
| |
| import ( |
| "context" |
| |
| "golang.org/x/tools/gopls/internal/file" |
| "golang.org/x/tools/gopls/internal/golang" |
| "golang.org/x/tools/gopls/internal/protocol" |
| "golang.org/x/tools/internal/event" |
| "golang.org/x/tools/internal/event/tag" |
| ) |
| |
| func (s *server) SignatureHelp(ctx context.Context, params *protocol.SignatureHelpParams) (*protocol.SignatureHelp, error) { |
| ctx, done := event.Start(ctx, "lsp.Server.signatureHelp", tag.URI.Of(params.TextDocument.URI)) |
| defer done() |
| |
| fh, snapshot, release, err := s.fileOf(ctx, params.TextDocument.URI) |
| if err != nil { |
| return nil, err |
| } |
| defer release() |
| |
| if snapshot.FileKind(fh) != file.Go { |
| return nil, nil // empty result |
| } |
| |
| info, activeParameter, err := golang.SignatureHelp(ctx, snapshot, fh, params.Position) |
| if err != nil { |
| event.Error(ctx, "no signature help", err, tag.Position.Of(params.Position)) |
| return nil, nil // sic? There could be many reasons for failure. |
| } |
| return &protocol.SignatureHelp{ |
| Signatures: []protocol.SignatureInformation{*info}, |
| ActiveParameter: uint32(activeParameter), |
| }, nil |
| } |