--- /dev/null
+// Copyright 2019 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 cmd
+
+import (
+ "context"
+ "flag"
+ "fmt"
+ "io/ioutil"
+
+ "golang.org/x/tools/internal/lsp/diff"
+ "golang.org/x/tools/internal/lsp/protocol"
+ "golang.org/x/tools/internal/lsp/source"
+ "golang.org/x/tools/internal/span"
+ errors "golang.org/x/xerrors"
+)
+
+// format implements the format verb for gopls.
+type format struct {
+ Diff bool `flag:"d" help:"display diffs instead of rewriting files"`
+ Write bool `flag:"w" help:"write result to (source) file instead of stdout"`
+ List bool `flag:"l" help:"list files whose formatting differs from gofmt's"`
+
+ app *Application
+}
+
+func (c *format) Name() string { return "format" }
+func (c *format) Usage() string { return "<filerange>" }
+func (c *format) ShortHelp() string { return "format the code according to the go standard" }
+func (c *format) DetailedHelp(f *flag.FlagSet) {
+ fmt.Fprint(f.Output(), `
+The arguments supplied may be simple file names, or ranges within files.
+
+Example: reformat this file:
+
+ $ gopls format -w internal/lsp/cmd/check.go
+
+ gopls format flags are:
+`)
+ f.PrintDefaults()
+}
+
+// Run performs the check on the files specified by args and prints the
+// results to stdout.
+func (c *format) Run(ctx context.Context, args ...string) error {
+ if len(args) == 0 {
+ // no files, so no results
+ return nil
+ }
+ // now we ready to kick things off
+ conn, err := c.app.connect(ctx)
+ if err != nil {
+ return err
+ }
+ defer conn.terminate(ctx)
+ for _, arg := range args {
+ spn := span.Parse(arg)
+ file := conn.AddFile(ctx, spn.URI())
+ if file.err != nil {
+ return file.err
+ }
+ filename := spn.URI().Filename()
+ loc, err := file.mapper.Location(spn)
+ if err != nil {
+ return err
+ }
+ if loc.Range.Start != loc.Range.End {
+ return errors.Errorf("only full file formatting supported")
+ }
+ p := protocol.DocumentFormattingParams{
+ TextDocument: protocol.TextDocumentIdentifier{URI: loc.URI},
+ }
+ edits, err := conn.Formatting(ctx, &p)
+ if err != nil {
+ return errors.Errorf("%v: %v", spn, err)
+ }
+ sedits, err := source.FromProtocolEdits(file.mapper, edits)
+ if err != nil {
+ return errors.Errorf("%v: %v", spn, err)
+ }
+ formatted := diff.ApplyEdits(string(file.mapper.Content), sedits)
+ printIt := true
+ if c.List {
+ printIt = false
+ if len(edits) > 0 {
+ fmt.Println(filename)
+ }
+ }
+ if c.Write {
+ printIt = false
+ if len(edits) > 0 {
+ ioutil.WriteFile(filename, []byte(formatted), 0644)
+ }
+ }
+ if c.Diff {
+ printIt = false
+ u := diff.ToUnified(filename+".orig", filename, string(file.mapper.Content), sedits)
+ fmt.Print(u)
+ }
+ if printIt {
+ fmt.Print(formatted)
+ }
+ }
+ return nil
+}