blob: cc7d72a1187044096da946fc4a0565283c4548ec [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 source provides core features for use by Go editors and tools.
package source
import (
"bytes"
"context"
"fmt"
"go/format"
"strings"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/go/packages"
"golang.org/x/tools/imports"
"golang.org/x/tools/internal/lsp/diff"
"golang.org/x/tools/internal/span"
)
// Format formats a file with a given range.
func Format(ctx context.Context, f File, rng span.Range) ([]TextEdit, error) {
pkg := f.GetPackage(ctx)
if hasParseErrors(pkg.GetErrors()) {
return nil, fmt.Errorf("%s has parse errors, not formatting", f.URI())
}
fAST := f.GetAST(ctx)
path, exact := astutil.PathEnclosingInterval(fAST, rng.Start, rng.End)
if !exact || len(path) == 0 {
return nil, fmt.Errorf("no exact AST node matching the specified range")
}
node := path[0]
// format.Node changes slightly from one release to another, so the version
// of Go used to build the LSP server will determine how it formats code.
// This should be acceptable for all users, who likely be prompted to rebuild
// the LSP server on each Go release.
fset := f.GetFileSet(ctx)
buf := &bytes.Buffer{}
if err := format.Node(buf, fset, node); err != nil {
return nil, err
}
return computeTextEdits(ctx, f, buf.String()), nil
}
func hasParseErrors(errors []packages.Error) bool {
for _, err := range errors {
if err.Kind == packages.ParseError {
return true
}
}
return false
}
// Imports formats a file using the goimports tool.
func Imports(ctx context.Context, f File, rng span.Range) ([]TextEdit, error) {
formatted, err := imports.Process(f.GetToken(ctx).Name(), f.GetContent(ctx), nil)
if err != nil {
return nil, err
}
return computeTextEdits(ctx, f, string(formatted)), nil
}
func computeTextEdits(ctx context.Context, file File, formatted string) (edits []TextEdit) {
u := strings.SplitAfter(string(file.GetContent(ctx)), "\n")
f := strings.SplitAfter(formatted, "\n")
for _, op := range diff.Operations(u, f) {
s := span.New(file.URI(), span.NewPoint(op.I1+1, 1, 0), span.NewPoint(op.I2+1, 1, 0))
switch op.Kind {
case diff.Delete:
// Delete: unformatted[i1:i2] is deleted.
edits = append(edits, TextEdit{Span: s})
case diff.Insert:
// Insert: formatted[j1:j2] is inserted at unformatted[i1:i1].
edits = append(edits, TextEdit{Span: s, NewText: strings.Join(op.Content, "")})
}
}
return edits
}