mirror of
https://github.com/golang/go
synced 2024-10-01 12:48:33 -06:00
69a2705782
we don't really use them, only generate them in cases where the failure is way more fundamental, and then also fail to remember them for the next call to the same accessor. Better to not have them. Change-Id: I0e8abeda688f5cc2a932ed95a80d89225c399f93 Reviewed-on: https://go-review.googlesource.com/c/162399 Reviewed-by: Rebecca Stambler <rstambler@golang.org>
106 lines
3.0 KiB
Go
106 lines
3.0 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"
|
|
"go/token"
|
|
"strings"
|
|
|
|
"golang.org/x/tools/go/ast/astutil"
|
|
"golang.org/x/tools/imports"
|
|
"golang.org/x/tools/internal/lsp/diff"
|
|
)
|
|
|
|
// Format formats a file with a given range.
|
|
func Format(ctx context.Context, f File, rng Range) ([]TextEdit, error) {
|
|
fAST := f.GetAST()
|
|
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 := f.GetFileSet()
|
|
buf := &bytes.Buffer{}
|
|
if err := format.Node(buf, fset, node); err != nil {
|
|
return nil, err
|
|
}
|
|
content, err := f.Read()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
tok := f.GetToken()
|
|
return computeTextEdits(rng, tok, string(content), buf.String()), nil
|
|
}
|
|
|
|
// Imports formats a file using the goimports tool.
|
|
func Imports(ctx context.Context, tok *token.File, content []byte, rng Range) ([]TextEdit, error) {
|
|
formatted, err := imports.Process(tok.Name(), content, nil)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return computeTextEdits(rng, tok, string(content), string(formatted)), nil
|
|
}
|
|
|
|
func computeTextEdits(rng Range, tok *token.File, unformatted, formatted string) (edits []TextEdit) {
|
|
u := strings.SplitAfter(unformatted, "\n")
|
|
f := strings.SplitAfter(formatted, "\n")
|
|
for _, op := range diff.Operations(u, f) {
|
|
start := lineStart(tok, op.I1+1)
|
|
if start == token.NoPos && op.I1 == len(u) {
|
|
start = tok.Pos(tok.Size())
|
|
}
|
|
end := lineStart(tok, op.I2+1)
|
|
if end == token.NoPos && op.I2 == len(u) {
|
|
end = tok.Pos(tok.Size())
|
|
}
|
|
switch op.Kind {
|
|
case diff.Delete:
|
|
// Delete: unformatted[i1:i2] is deleted.
|
|
edits = append(edits, TextEdit{
|
|
Range: Range{
|
|
Start: start,
|
|
End: end,
|
|
},
|
|
})
|
|
case diff.Insert:
|
|
// Insert: formatted[j1:j2] is inserted at unformatted[i1:i1].
|
|
edits = append(edits, TextEdit{
|
|
Range: Range{
|
|
Start: start,
|
|
End: start,
|
|
},
|
|
NewText: op.Content,
|
|
})
|
|
}
|
|
}
|
|
return edits
|
|
}
|