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go/internal/lsp/source/format.go
Rebecca Stambler 57eff0d8ac internal/lsp: add support for running goimports as a code action
This change adds support for goimports as a code action that can be run
on save. However, there do appear to be issues with the propagation of
the context.Only field of the CodeActionParams, so we treat every
codeAction as an organizeImports action - this should be fixed in the
next vscode-languageclient release
(https://github.com/Microsoft/vscode-languageserver-node/issues/442).

Change-Id: I64ca0034c393762248fde6521aba86ed9d41bf70
Reviewed-on: https://go-review.googlesource.com/c/154338
Reviewed-by: Ian Cottrell <iancottrell@google.com>
2018-12-17 20:01:16 +00:00

79 lines
2.2 KiB
Go

// 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/ast"
"go/format"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/imports"
)
// Format formats a file with a given range.
func Format(ctx context.Context, f File, rng Range) ([]TextEdit, error) {
fAST, err := f.GetAST()
if err != nil {
return nil, err
}
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 can fail when the AST contains a bad expression or
// statement. For now, we preemptively check for one.
// TODO(rstambler): This should really return an error from format.Node.
var isBad bool
ast.Inspect(node, func(n ast.Node) bool {
switch n.(type) {
case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
isBad = true
return false
default:
return true
}
})
if isBad {
return nil, fmt.Errorf("unable to format file due to a badly formatted AST")
}
// 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, err := f.GetFileSet()
if err != nil {
return nil, err
}
buf := &bytes.Buffer{}
if err := format.Node(buf, fset, node); err != nil {
return nil, err
}
return computeTextEdits(rng, buf.String()), nil
}
// Imports formats a file using the goimports tool.
func Imports(ctx context.Context, filename string, content []byte, rng Range) ([]TextEdit, error) {
content, err := imports.Process(filename, content, nil)
if err != nil {
return nil, err
}
return computeTextEdits(rng, string(content)), nil
}
// TODO(rstambler): Compute text edits instead of replacing whole file.
func computeTextEdits(rng Range, content string) []TextEdit {
return []TextEdit{
{
Range: rng,
NewText: content,
},
}
}