blob: aa485a53107d9e2b9492a2a05301296e955b13ad [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"
"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 GoFile, rng span.Range) ([]TextEdit, error) {
file := f.GetAST(ctx)
if file == nil {
return nil, fmt.Errorf("no AST for %s", f.URI())
}
pkg := f.GetPackage(ctx)
if hasListErrors(pkg.GetErrors()) || hasParseErrors(pkg.GetErrors()) {
return nil, fmt.Errorf("%s has parse errors, not formatting", f.URI())
}
path, exact := astutil.PathEnclosingInterval(file, 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.FileSet()
buf := &bytes.Buffer{}
if err := format.Node(buf, fset, node); err != nil {
return nil, err
}
return computeTextEdits(ctx, f, buf.String()), nil
}
// Imports formats a file using the goimports tool.
func Imports(ctx context.Context, f GoFile, rng span.Range) ([]TextEdit, error) {
data, _, err := f.Handle(ctx).Read(ctx)
if err != nil {
return nil, err
}
pkg := f.GetPackage(ctx)
if pkg == nil || pkg.IsIllTyped() {
return nil, fmt.Errorf("no package for file %s", f.URI())
}
if hasListErrors(pkg.GetErrors()) {
return nil, fmt.Errorf("%s has list errors, not running goimports", f.URI())
}
formatted, err := imports.Process(f.URI().Filename(), data, nil)
if err != nil {
return nil, err
}
return computeTextEdits(ctx, f, string(formatted)), nil
}
func hasParseErrors(errors []packages.Error) bool {
for _, err := range errors {
if err.Kind == packages.ParseError {
return true
}
}
return false
}
func hasListErrors(errors []packages.Error) bool {
for _, err := range errors {
if err.Kind == packages.ListError {
return true
}
}
return false
}
func computeTextEdits(ctx context.Context, file File, formatted string) (edits []TextEdit) {
data, _, err := file.Handle(ctx).Read(ctx)
if err != nil {
file.View().Session().Logger().Errorf(ctx, "Cannot compute text edits: %v", err)
return nil
}
u := diff.SplitLines(string(data))
f := diff.SplitLines(formatted)
return DiffToEdits(file.URI(), diff.Operations(u, f))
}