blob: 2ad5d265fc1668f91c182432daacb96304c3e6d8 [file] [log] [blame]
// 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 source
import (
"bytes"
"context"
"go/ast"
"go/format"
"go/token"
"go/types"
"regexp"
"strings"
"golang.org/x/tools/go/types/typeutil"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/lsp/diff"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/span"
"golang.org/x/tools/refactor/satisfy"
errors "golang.org/x/xerrors"
)
type renamer struct {
ctx context.Context
fset *token.FileSet
refs []*ReferenceInfo
objsToUpdate map[types.Object]bool
hadConflicts bool
errors string
from, to string
satisfyConstraints map[satisfy.Constraint]bool
packages map[*types.Package]Package // may include additional packages that are a rdep of pkg
msets typeutil.MethodSetCache
changeMethods bool
}
type PrepareItem struct {
Range protocol.Range
Text string
}
// PrepareRename searches for a valid renaming at position pp.
//
// The returned usererr is intended to be displayed to the user to explain why
// the prepare fails. Probably we could eliminate the redundancy in returning
// two errors, but for now this is done defensively.
func PrepareRename(ctx context.Context, snapshot Snapshot, f FileHandle, pp protocol.Position) (_ *PrepareItem, usererr, err error) {
ctx, done := event.Start(ctx, "source.PrepareRename")
defer done()
qos, err := qualifiedObjsAtProtocolPos(ctx, snapshot, f.URI(), pp)
if err != nil {
return nil, nil, err
}
node, obj, pkg := qos[0].node, qos[0].obj, qos[0].sourcePkg
if err := checkRenamable(obj); err != nil {
return nil, err, err
}
mr, err := posToMappedRange(snapshot, pkg, node.Pos(), node.End())
if err != nil {
return nil, nil, err
}
rng, err := mr.Range()
if err != nil {
return nil, nil, err
}
if _, isImport := node.(*ast.ImportSpec); isImport {
// We're not really renaming the import path.
rng.End = rng.Start
}
return &PrepareItem{
Range: rng,
Text: obj.Name(),
}, nil, nil
}
// checkRenamable verifies if an obj may be renamed.
func checkRenamable(obj types.Object) error {
if v, ok := obj.(*types.Var); ok && v.Embedded() {
return errors.New("can't rename embedded fields: rename the type directly or name the field")
}
if obj.Name() == "_" {
return errors.New("can't rename \"_\"")
}
return nil
}
// Rename returns a map of TextEdits for each file modified when renaming a
// given identifier within a package.
func Rename(ctx context.Context, s Snapshot, f FileHandle, pp protocol.Position, newName string) (map[span.URI][]protocol.TextEdit, error) {
ctx, done := event.Start(ctx, "source.Rename")
defer done()
qos, err := qualifiedObjsAtProtocolPos(ctx, s, f.URI(), pp)
if err != nil {
return nil, err
}
obj, pkg := qos[0].obj, qos[0].pkg
if err := checkRenamable(obj); err != nil {
return nil, err
}
if obj.Name() == newName {
return nil, errors.Errorf("old and new names are the same: %s", newName)
}
if !isValidIdentifier(newName) {
return nil, errors.Errorf("invalid identifier to rename: %q", newName)
}
if pkg == nil || pkg.IsIllTyped() {
return nil, errors.Errorf("package for %s is ill typed", f.URI())
}
refs, err := references(ctx, s, qos, true, false, true)
if err != nil {
return nil, err
}
r := renamer{
ctx: ctx,
fset: s.FileSet(),
refs: refs,
objsToUpdate: make(map[types.Object]bool),
from: obj.Name(),
to: newName,
packages: make(map[*types.Package]Package),
}
// A renaming initiated at an interface method indicates the
// intention to rename abstract and concrete methods as needed
// to preserve assignability.
for _, ref := range refs {
if obj, ok := ref.obj.(*types.Func); ok {
recv := obj.Type().(*types.Signature).Recv()
if recv != nil && IsInterface(recv.Type().Underlying()) {
r.changeMethods = true
break
}
}
}
for _, from := range refs {
r.packages[from.pkg.GetTypes()] = from.pkg
}
// Check that the renaming of the identifier is ok.
for _, ref := range refs {
r.check(ref.obj)
if r.hadConflicts { // one error is enough.
break
}
}
if r.hadConflicts {
return nil, errors.Errorf(r.errors)
}
changes, err := r.update()
if err != nil {
return nil, err
}
result := make(map[span.URI][]protocol.TextEdit)
for uri, edits := range changes {
// These edits should really be associated with FileHandles for maximal correctness.
// For now, this is good enough.
fh, err := s.GetFile(ctx, uri)
if err != nil {
return nil, err
}
data, err := fh.Read()
if err != nil {
return nil, err
}
converter := span.NewContentConverter(uri.Filename(), data)
m := &protocol.ColumnMapper{
URI: uri,
Converter: converter,
Content: data,
}
// Sort the edits first.
diff.SortTextEdits(edits)
protocolEdits, err := ToProtocolEdits(m, edits)
if err != nil {
return nil, err
}
result[uri] = protocolEdits
}
return result, nil
}
// Rename all references to the identifier.
func (r *renamer) update() (map[span.URI][]diff.TextEdit, error) {
result := make(map[span.URI][]diff.TextEdit)
seen := make(map[span.Span]bool)
docRegexp, err := regexp.Compile(`\b` + r.from + `\b`)
if err != nil {
return nil, err
}
for _, ref := range r.refs {
refSpan, err := ref.spanRange.Span()
if err != nil {
return nil, err
}
if seen[refSpan] {
continue
}
seen[refSpan] = true
// Renaming a types.PkgName may result in the addition or removal of an identifier,
// so we deal with this separately.
if pkgName, ok := ref.obj.(*types.PkgName); ok && ref.isDeclaration {
edit, err := r.updatePkgName(pkgName)
if err != nil {
return nil, err
}
result[refSpan.URI()] = append(result[refSpan.URI()], *edit)
continue
}
// Replace the identifier with r.to.
edit := diff.TextEdit{
Span: refSpan,
NewText: r.to,
}
result[refSpan.URI()] = append(result[refSpan.URI()], edit)
if !ref.isDeclaration || ref.ident == nil { // uses do not have doc comments to update.
continue
}
doc := r.docComment(ref.pkg, ref.ident)
if doc == nil {
continue
}
// Perform the rename in doc comments declared in the original package.
// go/parser strips out \r\n returns from the comment text, so go
// line-by-line through the comment text to get the correct positions.
for _, comment := range doc.List {
if isDirective(comment.Text) {
continue
}
lines := strings.Split(comment.Text, "\n")
tok := r.fset.File(comment.Pos())
commentLine := tok.Position(comment.Pos()).Line
for i, line := range lines {
lineStart := comment.Pos()
if i > 0 {
lineStart = tok.LineStart(commentLine + i)
}
for _, locs := range docRegexp.FindAllIndex([]byte(line), -1) {
rng := span.NewRange(r.fset, lineStart+token.Pos(locs[0]), lineStart+token.Pos(locs[1]))
spn, err := rng.Span()
if err != nil {
return nil, err
}
result[spn.URI()] = append(result[spn.URI()], diff.TextEdit{
Span: spn,
NewText: r.to,
})
}
}
}
}
return result, nil
}
// docComment returns the doc for an identifier.
func (r *renamer) docComment(pkg Package, id *ast.Ident) *ast.CommentGroup {
_, nodes, _ := pathEnclosingInterval(r.fset, pkg, id.Pos(), id.End())
for _, node := range nodes {
switch decl := node.(type) {
case *ast.FuncDecl:
return decl.Doc
case *ast.Field:
return decl.Doc
case *ast.GenDecl:
return decl.Doc
// For {Type,Value}Spec, if the doc on the spec is absent,
// search for the enclosing GenDecl
case *ast.TypeSpec:
if decl.Doc != nil {
return decl.Doc
}
case *ast.ValueSpec:
if decl.Doc != nil {
return decl.Doc
}
case *ast.Ident:
case *ast.AssignStmt:
// *ast.AssignStmt doesn't have an associated comment group.
// So, we try to find a comment just before the identifier.
// Try to find a comment group only for short variable declarations (:=).
if decl.Tok != token.DEFINE {
return nil
}
var file *ast.File
for _, f := range pkg.GetSyntax() {
if f.Pos() <= id.Pos() && id.Pos() <= f.End() {
file = f
break
}
}
if file == nil {
return nil
}
identLine := r.fset.Position(id.Pos()).Line
for _, comment := range file.Comments {
if comment.Pos() > id.Pos() {
// Comment is after the identifier.
continue
}
lastCommentLine := r.fset.Position(comment.End()).Line
if lastCommentLine+1 == identLine {
return comment
}
}
default:
return nil
}
}
return nil
}
// updatePkgName returns the updates to rename a pkgName in the import spec
func (r *renamer) updatePkgName(pkgName *types.PkgName) (*diff.TextEdit, error) {
// Modify ImportSpec syntax to add or remove the Name as needed.
pkg := r.packages[pkgName.Pkg()]
_, path, _ := pathEnclosingInterval(r.fset, pkg, pkgName.Pos(), pkgName.Pos())
if len(path) < 2 {
return nil, errors.Errorf("no path enclosing interval for %s", pkgName.Name())
}
spec, ok := path[1].(*ast.ImportSpec)
if !ok {
return nil, errors.Errorf("failed to update PkgName for %s", pkgName.Name())
}
var astIdent *ast.Ident // will be nil if ident is removed
if pkgName.Imported().Name() != r.to {
// ImportSpec.Name needed
astIdent = &ast.Ident{NamePos: spec.Path.Pos(), Name: r.to}
}
// Make a copy of the ident that just has the name and path.
updated := &ast.ImportSpec{
Name: astIdent,
Path: spec.Path,
EndPos: spec.EndPos,
}
rng := span.NewRange(r.fset, spec.Pos(), spec.End())
spn, err := rng.Span()
if err != nil {
return nil, err
}
var buf bytes.Buffer
format.Node(&buf, r.fset, updated)
newText := buf.String()
return &diff.TextEdit{
Span: spn,
NewText: newText,
}, nil
}