mirror of
https://github.com/golang/go
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508f945e1a
Like the previous change to the FIle interface, we treat Read as if it were an accessor, we remember the content part but not the error part, and we may fill it in asynchronously, so this change makes it explicit. In the future we should probably trap the error in the read and push it back through another channel though, it will be the root cause of later errors. Change-Id: I3d374dd557178b4e8c5544813cd77f5c0faefe5b Reviewed-on: https://go-review.googlesource.com/c/162403 Run-TryBot: Ian Cottrell <iancottrell@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rebecca Stambler <rstambler@golang.org>
102 lines
2.8 KiB
Go
102 lines
2.8 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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"go/token"
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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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)
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// Format formats a file with a given range.
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func Format(ctx context.Context, f File, rng Range) ([]TextEdit, error) {
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fAST := f.GetAST()
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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()
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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(rng, 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 Range) ([]TextEdit, error) {
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formatted, err := imports.Process(f.GetToken().Name(), f.GetContent(), 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(rng, f, string(formatted)), nil
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}
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func computeTextEdits(rng Range, file File, formatted string) (edits []TextEdit) {
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u := strings.SplitAfter(string(file.GetContent()), "\n")
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tok := file.GetToken()
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f := strings.SplitAfter(formatted, "\n")
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for _, op := range diff.Operations(u, f) {
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start := lineStart(tok, op.I1+1)
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if start == token.NoPos && op.I1 == len(u) {
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start = tok.Pos(tok.Size())
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}
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end := lineStart(tok, op.I2+1)
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if end == token.NoPos && op.I2 == len(u) {
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end = tok.Pos(tok.Size())
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}
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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{
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Range: Range{
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Start: start,
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End: end,
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},
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})
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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{
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Range: Range{
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Start: start,
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End: start,
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},
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NewText: op.Content,
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})
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}
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}
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return edits
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}
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