blob: 06af1bdaec0da4f71a52b0d62452a45d22de2505 [file] [log] [blame]
// 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 lsp
import (
"context"
"fmt"
"strings"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/lsp/debug/tag"
"golang.org/x/tools/internal/lsp/lsppos"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/lsp/source/completion"
"golang.org/x/tools/internal/lsp/template"
"golang.org/x/tools/internal/lsp/work"
)
func (s *Server) completion(ctx context.Context, params *protocol.CompletionParams) (*protocol.CompletionList, error) {
snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.UnknownKind)
defer release()
if !ok {
return nil, err
}
var candidates []completion.CompletionItem
var surrounding *completion.Selection
switch snapshot.View().FileKind(fh) {
case source.Go:
candidates, surrounding, err = completion.Completion(ctx, snapshot, fh, params.Position, params.Context)
case source.Mod:
candidates, surrounding = nil, nil
case source.Work:
cl, err := work.Completion(ctx, snapshot, fh, params.Position)
if err != nil {
break
}
return cl, nil
case source.Tmpl:
var cl *protocol.CompletionList
cl, err = template.Completion(ctx, snapshot, fh, params.Position, params.Context)
if err != nil {
break // use common error handling, candidates==nil
}
return cl, nil
}
if err != nil {
event.Error(ctx, "no completions found", err, tag.Position.Of(params.Position))
}
if candidates == nil {
return &protocol.CompletionList{
IsIncomplete: true,
Items: []protocol.CompletionItem{},
}, nil
}
// Map positions to LSP positions using the original content, rather than
// internal/span, as the latter treats end of file as the beginning of the
// next line, even when it's not newline-terminated. See golang/go#41029 for
// more details.
src, err := fh.Read()
if err != nil {
return nil, err
}
tf := snapshot.FileSet().File(surrounding.Start())
mapper := lsppos.NewTokenMapper(src, tf)
rng, err := mapper.Range(surrounding.Start(), surrounding.End())
if err != nil {
return nil, err
}
// When using deep completions/fuzzy matching, report results as incomplete so
// client fetches updated completions after every key stroke.
options := snapshot.View().Options()
incompleteResults := options.DeepCompletion || options.Matcher == source.Fuzzy
items := toProtocolCompletionItems(candidates, rng, options)
return &protocol.CompletionList{
IsIncomplete: incompleteResults,
Items: items,
}, nil
}
func toProtocolCompletionItems(candidates []completion.CompletionItem, rng protocol.Range, options *source.Options) []protocol.CompletionItem {
var (
items = make([]protocol.CompletionItem, 0, len(candidates))
numDeepCompletionsSeen int
)
for i, candidate := range candidates {
// Limit the number of deep completions to not overwhelm the user in cases
// with dozens of deep completion matches.
if candidate.Depth > 0 {
if !options.DeepCompletion {
continue
}
if numDeepCompletionsSeen >= completion.MaxDeepCompletions {
continue
}
numDeepCompletionsSeen++
}
insertText := candidate.InsertText
if options.InsertTextFormat == protocol.SnippetTextFormat {
insertText = candidate.Snippet()
}
// This can happen if the client has snippets disabled but the
// candidate only supports snippet insertion.
if insertText == "" {
continue
}
item := protocol.CompletionItem{
Label: candidate.Label,
Detail: candidate.Detail,
Kind: candidate.Kind,
TextEdit: &protocol.TextEdit{
NewText: insertText,
Range: rng,
},
InsertTextFormat: options.InsertTextFormat,
AdditionalTextEdits: candidate.AdditionalTextEdits,
// This is a hack so that the client sorts completion results in the order
// according to their score. This can be removed upon the resolution of
// https://github.com/Microsoft/language-server-protocol/issues/348.
SortText: fmt.Sprintf("%05d", i),
// Trim operators (VSCode doesn't like weird characters in
// filterText).
FilterText: strings.TrimLeft(candidate.InsertText, "&*"),
Preselect: i == 0,
Documentation: candidate.Documentation,
Tags: candidate.Tags,
Deprecated: candidate.Deprecated,
}
items = append(items, item)
}
return items
}