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https://github.com/golang/go
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b184d1ccfc
This also means we don't need the J2 becasue it is implied by len(Content) Change-Id: I04e2cbaa3e1faa1e3add22ec2d478821b9062419 Reviewed-on: https://go-review.googlesource.com/c/tools/+/170878 Run-TryBot: Ian Cottrell <iancottrell@google.com> Reviewed-by: Rebecca Stambler <rstambler@golang.org>
83 lines
2.6 KiB
Go
83 lines
2.6 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package source provides core features for use by Go editors and tools.
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package source
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import (
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"bytes"
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"context"
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"fmt"
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"go/ast"
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"go/format"
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"strings"
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"golang.org/x/tools/go/ast/astutil"
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"golang.org/x/tools/imports"
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"golang.org/x/tools/internal/lsp/diff"
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"golang.org/x/tools/internal/span"
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)
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// Format formats a file with a given range.
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func Format(ctx context.Context, f File, rng span.Range) ([]TextEdit, error) {
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fAST := f.GetAST(ctx)
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path, exact := astutil.PathEnclosingInterval(fAST, rng.Start, rng.End)
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if !exact || len(path) == 0 {
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return nil, fmt.Errorf("no exact AST node matching the specified range")
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}
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node := path[0]
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// format.Node can fail when the AST contains a bad expression or
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// statement. For now, we preemptively check for one.
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// TODO(rstambler): This should really return an error from format.Node.
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var isBad bool
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ast.Inspect(node, func(n ast.Node) bool {
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switch n.(type) {
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case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
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isBad = true
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return false
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default:
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return true
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}
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})
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if isBad {
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return nil, fmt.Errorf("unable to format file due to a badly formatted AST")
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}
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// format.Node changes slightly from one release to another, so the version
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// of Go used to build the LSP server will determine how it formats code.
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// This should be acceptable for all users, who likely be prompted to rebuild
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// the LSP server on each Go release.
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fset := f.GetFileSet(ctx)
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buf := &bytes.Buffer{}
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if err := format.Node(buf, fset, node); err != nil {
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return nil, err
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}
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return computeTextEdits(ctx, f, buf.String()), nil
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}
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// Imports formats a file using the goimports tool.
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func Imports(ctx context.Context, f File, rng span.Range) ([]TextEdit, error) {
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formatted, err := imports.Process(f.GetToken(ctx).Name(), f.GetContent(ctx), nil)
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if err != nil {
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return nil, err
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}
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return computeTextEdits(ctx, f, string(formatted)), nil
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}
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func computeTextEdits(ctx context.Context, file File, formatted string) (edits []TextEdit) {
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u := strings.SplitAfter(string(file.GetContent(ctx)), "\n")
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f := strings.SplitAfter(formatted, "\n")
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for _, op := range diff.Operations(u, f) {
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s := span.New(file.URI(), span.NewPoint(op.I1+1, 1, 0), span.NewPoint(op.I2+1, 1, 0))
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switch op.Kind {
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case diff.Delete:
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// Delete: unformatted[i1:i2] is deleted.
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edits = append(edits, TextEdit{Span: s})
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case diff.Insert:
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// Insert: formatted[j1:j2] is inserted at unformatted[i1:i1].
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edits = append(edits, TextEdit{Span: s, NewText: strings.Join(op.Content, "")})
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}
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}
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return edits
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}
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