blob: 89142f420075f7334d21d5a7c18ad45d2b3eb51c [file] [log] [blame]
// Copyright 2022 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"
"fmt"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/gopls/internal/cache/parsego"
"golang.org/x/tools/gopls/internal/file"
"golang.org/x/tools/gopls/internal/protocol"
"golang.org/x/tools/internal/event"
)
// selectionRange defines the textDocument/selectionRange feature,
// which, given a list of positions within a file,
// reports a linked list of enclosing syntactic blocks, innermost first.
//
// See https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_selectionRange.
//
// This feature can be used by a client to implement "expand selection" in a
// language-aware fashion. Multiple input positions are supported to allow
// for multiple cursors, and the entire path up to the whole document is
// returned for each cursor to avoid multiple round-trips when the user is
// likely to issue this command multiple times in quick succession.
func (s *server) SelectionRange(ctx context.Context, params *protocol.SelectionRangeParams) ([]protocol.SelectionRange, error) {
ctx, done := event.Start(ctx, "lsp.Server.selectionRange")
defer done()
fh, snapshot, release, err := s.fileOf(ctx, params.TextDocument.URI)
if err != nil {
return nil, err
}
defer release()
if kind := snapshot.FileKind(fh); kind != file.Go {
return nil, fmt.Errorf("SelectionRange not supported for file of type %s", kind)
}
pgf, err := snapshot.ParseGo(ctx, fh, parsego.ParseFull)
if err != nil {
return nil, err
}
result := make([]protocol.SelectionRange, len(params.Positions))
for i, protocolPos := range params.Positions {
pos, err := pgf.PositionPos(protocolPos)
if err != nil {
return nil, err
}
path, _ := astutil.PathEnclosingInterval(pgf.File, pos, pos)
tail := &result[i] // tail of the Parent linked list, built head first
for j, node := range path {
rng, err := pgf.NodeRange(node)
if err != nil {
return nil, err
}
// Add node to tail.
if j > 0 {
tail.Parent = &protocol.SelectionRange{}
tail = tail.Parent
}
tail.Range = rng
}
}
return result, nil
}