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// Copyright 2019 CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package protobuf
import (
"bytes"
"fmt"
"os"
"path"
"path/filepath"
"sort"
"strconv"
"strings"
"text/scanner"
"unicode"
"github.com/emicklei/proto"
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/errors"
"cuelang.org/go/cue/parser"
"cuelang.org/go/cue/token"
"cuelang.org/go/internal/source"
)
func (s *Extractor) parse(filename string, src interface{}) (p *protoConverter, err error) {
if filename == "" {
return nil, errors.Newf(token.NoPos, "empty filename")
}
if r, ok := s.fileCache[filename]; ok {
return r.p, r.err
}
defer func() {
s.fileCache[filename] = result{p, err}
}()
b, err := source.Read(filename, src)
if err != nil {
return nil, err
}
parser := proto.NewParser(bytes.NewReader(b))
if filename != "" {
parser.Filename(filename)
}
d, err := parser.Parse()
if err != nil {
return nil, errors.Newf(token.NoPos, "protobuf: %v", err)
}
tfile := token.NewFile(filename, 0, len(b))
tfile.SetLinesForContent(b)
p = &protoConverter{
id: filename,
state: s,
tfile: tfile,
imported: map[string]bool{},
symbols: map[string]bool{},
aliases: map[string]string{},
}
defer func() {
switch x := recover().(type) {
case nil:
case protoError:
err = &protobufError{
path: p.path,
pos: p.toCUEPos(x.pos),
err: x.error,
}
default:
panic(x)
}
}()
p.file = &ast.File{Filename: filename}
p.addNames(d.Elements)
// Parse package definitions.
for _, e := range d.Elements {
switch x := e.(type) {
case *proto.Package:
p.protoPkg = x.Name
case *proto.Option:
if x.Name == "go_package" {
str, err := strconv.Unquote(x.Constant.SourceRepresentation())
if err != nil {
failf(x.Position, "unquoting package filed: %v", err)
}
split := strings.Split(str, ";")
switch {
case strings.Contains(split[0], "."):
p.cuePkgPath = split[0]
switch len(split) {
case 1:
p.shortPkgName = path.Base(str)
case 2:
p.shortPkgName = split[1]
default:
failf(x.Position, "unexpected ';' in %q", str)
}
case len(split) == 1:
p.shortPkgName = split[0]
default:
failf(x.Position, "malformed go_package clause %s", str)
}
// name.AddComment(comment(x.Comment, true))
// name.AddComment(comment(x.InlineComment, false))
}
}
}
if name := p.shortName(); name != "" {
p.file.Decls = append(p.file.Decls, &ast.Package{Name: ast.NewIdent(name)})
}
for _, e := range d.Elements {
switch x := e.(type) {
case *proto.Import:
if err := p.doImport(x); err != nil {
return nil, err
}
}
}
imports := &ast.ImportDecl{}
importIdx := len(p.file.Decls)
p.file.Decls = append(p.file.Decls, imports)
for _, e := range d.Elements {
p.topElement(e)
}
imported := []string{}
for k := range p.imported {
imported = append(imported, k)
}
sort.Strings(imported)
p.sorted = imported
for _, v := range imported {
spec := ast.NewImport(nil, v)
imports.Specs = append(imports.Specs, spec)
p.file.Imports = append(p.file.Imports, spec)
}
if len(imports.Specs) == 0 {
a := p.file.Decls
copy(a[importIdx:], a[importIdx+1:])
p.file.Decls = a[:len(a)-1]
}
return p, nil
}
// A protoConverter converts a proto definition to CUE. Proto files map to
// CUE files one to one.
type protoConverter struct {
state *Extractor
tfile *token.File
proto3 bool
id string
protoPkg string
shortPkgName string
cuePkgPath string
// w bytes.Buffer
file *ast.File
inBody bool
sorted []string
imported map[string]bool
path []string
scope []map[string]mapping // for symbols resolution within package.
symbols map[string]bool // symbols provided by package
aliases map[string]string // for shadowed packages
}
type mapping struct {
ref string
alias string // alias for the type, if exists.
pkg *protoConverter
}
func (p *protoConverter) importPath() string {
if p.cuePkgPath == "" && p.protoPkg != "" {
dir := strings.Replace(p.protoPkg, ".", "/", -1)
p.cuePkgPath = path.Join("googleapis.com", dir)
}
return p.cuePkgPath
}
func (p *protoConverter) shortName() string {
if p.shortPkgName == "" && p.protoPkg != "" {
split := strings.Split(p.protoPkg, ".")
p.shortPkgName = split[len(split)-1]
}
return p.shortPkgName
}
func (p *protoConverter) toCUEPos(pos scanner.Position) token.Pos {
return p.tfile.Pos(pos.Offset, 0)
}
func (p *protoConverter) addRef(pos scanner.Position, from, to string) {
top := p.scope[len(p.scope)-1]
if _, ok := top[from]; ok {
failf(pos, "entity %q already defined", from)
}
top[from] = mapping{ref: to}
}
func (p *protoConverter) addNames(elems []proto.Visitee) {
p.scope = append(p.scope, map[string]mapping{})
for _, e := range elems {
var pos scanner.Position
var name string
switch x := e.(type) {
case *proto.Message:
if x.IsExtend {
continue
}
name = x.Name
pos = x.Position
case *proto.Enum:
name = x.Name
pos = x.Position
case *proto.NormalField:
name = x.Name
pos = x.Position
case *proto.MapField:
name = x.Name
pos = x.Position
case *proto.Oneof:
name = x.Name
pos = x.Position
default:
continue
}
sym := strings.Join(append(p.path, name), ".")
p.symbols[sym] = true
p.addRef(pos, name, strings.Join(append(p.path, name), "_"))
}
}
func (p *protoConverter) popNames() {
p.scope = p.scope[:len(p.scope)-1]
}
func (p *protoConverter) uniqueTop(name string) string {
a := strings.SplitN(name, ".", 2)
for i := len(p.scope) - 1; i > 0; i-- {
if _, ok := p.scope[i][a[0]]; ok {
first := a[0]
alias, ok := p.aliases[first]
if !ok {
// TODO: this is likely to be okay, but find something better.
alias = "_" + first + "_"
p.file.Decls = append(p.file.Decls, &ast.Alias{
Ident: ast.NewIdent(alias),
Expr: ast.NewIdent(first),
})
p.aliases[first] = alias
}
if len(a) > 1 {
alias += "." + a[1]
}
return alias
}
}
return name
}
func (p *protoConverter) toExpr(pos scanner.Position, name string) (expr ast.Expr) {
expr, err := parser.ParseExpr("", name, parser.ParseComments)
if err != nil {
panic(err)
}
ast.SetPos(expr, p.toCUEPos(pos))
return expr
}
func (p *protoConverter) resolve(pos scanner.Position, name string, options []*proto.Option) string {
if s, ok := protoToCUE(name, options); ok {
return p.uniqueTop(s)
}
if strings.HasPrefix(name, ".") {
return p.resolveTopScope(pos, name[1:], options)
}
for i := len(p.scope) - 1; i > 0; i-- {
if m, ok := p.scope[i][name]; ok {
cueName := strings.Replace(m.ref, ".", "_", -1)
return cueName
}
}
return p.resolveTopScope(pos, name, options)
}
func (p *protoConverter) resolveTopScope(pos scanner.Position, name string, options []*proto.Option) string {
for i := 0; i < len(name); i++ {
k := strings.IndexByte(name[i:], '.')
i += k
if k == -1 {
i = len(name)
}
if m, ok := p.scope[0][name[:i]]; ok {
if m.pkg != nil {
p.imported[m.pkg.importPath()] = true
// TODO: do something more principled.
}
cueName := strings.Replace(name[i:], ".", "_", -1)
return p.uniqueTop(m.ref + cueName)
}
}
failf(pos, "name %q not found", name)
return ""
}
func (p *protoConverter) doImport(v *proto.Import) error {
if v.Filename == "cue/cue.proto" {
return nil
}
filename := ""
for _, p := range p.state.paths {
name := filepath.Join(p, v.Filename)
_, err := os.Stat(name)
if err != nil {
continue
}
filename = name
break
}
if filename == "" {
err := errors.Newf(p.toCUEPos(v.Position), "could not find import %q", v.Filename)
p.state.addErr(err)
return err
}
if !p.mapBuiltinPackage(v.Position, v.Filename, filename == "") {
return nil
}
imp, err := p.state.parse(filename, nil)
if err != nil {
fail(v.Position, err)
}
prefix := ""
if imp.importPath() != p.importPath() {
prefix = imp.shortName() + "."
}
pkgNamespace := strings.Split(imp.protoPkg, ".")
curNamespace := strings.Split(p.protoPkg, ".")
for {
for k := range imp.symbols {
ref := k
if len(pkgNamespace) > 0 {
ref = strings.Join(append(pkgNamespace, k), ".")
}
if _, ok := p.scope[0][ref]; !ok {
pkg := imp
if imp.importPath() == p.importPath() {
pkg = nil
}
p.scope[0][ref] = mapping{prefix + k, "", pkg}
}
}
if len(pkgNamespace) == 0 {
break
}
if len(curNamespace) == 0 || pkgNamespace[0] != curNamespace[0] {
break
}
pkgNamespace = pkgNamespace[1:]
curNamespace = curNamespace[1:]
}
return nil
}
func (p *protoConverter) stringLit(pos scanner.Position, s string) *ast.BasicLit {
return &ast.BasicLit{
ValuePos: p.toCUEPos(pos),
Kind: token.STRING,
Value: strconv.Quote(s)}
}
func (p *protoConverter) ident(pos scanner.Position, name string) *ast.Ident {
return &ast.Ident{NamePos: p.toCUEPos(pos), Name: labelName(name)}
}
func (p *protoConverter) ref(pos scanner.Position) *ast.Ident {
return &ast.Ident{NamePos: p.toCUEPos(pos), Name: strings.Join(p.path, "_")}
}
func (p *protoConverter) subref(pos scanner.Position, name string) *ast.Ident {
return &ast.Ident{
NamePos: p.toCUEPos(pos),
Name: strings.Join(append(p.path, name), "_"),
}
}
func (p *protoConverter) addTag(f *ast.Field, body string) {
tag := "@protobuf(" + body + ")"
f.Attrs = append(f.Attrs, &ast.Attribute{Text: tag})
}
func (p *protoConverter) topElement(v proto.Visitee) {
switch x := v.(type) {
case *proto.Syntax:
p.proto3 = x.Value == "proto3"
case *proto.Comment:
if p.inBody {
p.file.Decls = append(p.file.Decls, comment(x, true))
} else {
addComments(p.file, 0, x, nil)
}
case *proto.Enum:
p.enum(x)
case *proto.Package:
if doc := x.Doc(); doc != nil {
addComments(p.file, 0, doc, nil)
}
// p.inBody bool
case *proto.Message:
p.message(x)
case *proto.Option:
case *proto.Import:
// already handled.
case *proto.Service:
// TODO: handle services.
case *proto.Extensions, *proto.Reserved:
// no need to handle
default:
failf(scanner.Position{}, "unsupported type %T", x)
}
}
func (p *protoConverter) message(v *proto.Message) {
if v.IsExtend {
// TODO: we are not handling extensions as for now.
return
}
defer func(saved []string) { p.path = saved }(p.path)
p.path = append(p.path, v.Name)
p.addNames(v.Elements)
defer p.popNames()
// TODO: handle IsExtend/ proto2
s := &ast.StructLit{
Lbrace: p.toCUEPos(v.Position),
// TOOD: set proto file position.
Rbrace: token.Newline.Pos(),
}
ref := p.ref(v.Position)
if v.Comment == nil {
ref.NamePos = newSection
}
f := &ast.Field{Label: ref, Value: s}
addComments(f, 1, v.Comment, nil)
p.file.Decls = append(p.file.Decls, f)
for i, e := range v.Elements {
p.messageField(s, i, e)
}
}
func (p *protoConverter) messageField(s *ast.StructLit, i int, v proto.Visitee) {
switch x := v.(type) {
case *proto.Comment:
s.Elts = append(s.Elts, comment(x, true))
case *proto.NormalField:
f := p.parseField(s, i, x.Field)
if x.Repeated {
f.Value = &ast.ListLit{
Lbrack: p.toCUEPos(x.Position),
Elts: []ast.Expr{&ast.Ellipsis{Type: f.Value}},
}
}
case *proto.MapField:
defer func(saved []string) { p.path = saved }(p.path)
p.path = append(p.path, x.Name)
f := &ast.Field{}
// All keys are converted to strings.
// TODO: support integer keys.
f.Label = ast.NewList(ast.NewIdent("string"))
f.Value = p.toExpr(x.Position, p.resolve(x.Position, x.Type, x.Options))
name := p.ident(x.Position, x.Name)
f = &ast.Field{
Label: name,
Value: &ast.StructLit{Elts: []ast.Decl{f}},
}
addComments(f, i, x.Comment, x.InlineComment)
o := optionParser{message: s, field: f}
o.tags = fmt.Sprintf("%d,type=map<%s,%s>", x.Sequence, x.KeyType, x.Type)
if x.Name != name.Name {
o.tags += "," + x.Name
}
s.Elts = append(s.Elts, f)
o.parse(x.Options)
p.addTag(f, o.tags)
if !o.required {
f.Optional = token.NoSpace.Pos()
}
case *proto.Enum:
p.enum(x)
case *proto.Message:
p.message(x)
case *proto.Oneof:
p.oneOf(x)
case *proto.Extensions, *proto.Reserved:
// no need to handle
default:
failf(scanner.Position{}, "unsupported field type %T", v)
}
}
// enum converts a proto enum definition to CUE.
//
// An enum will generate two top-level definitions:
//
// Enum:
// "Value1" |
// "Value2" |
// "Value3"
//
// and
//
// Enum_value: {
// "Value1": 0
// "Value2": 1
// }
//
// Enums are always defined at the top level. The name of a nested enum
// will be prefixed with the name of its parent and an underscore.
func (p *protoConverter) enum(x *proto.Enum) {
if len(x.Elements) == 0 {
failf(x.Position, "empty enum")
}
name := p.subref(x.Position, x.Name)
defer func(saved []string) { p.path = saved }(p.path)
p.path = append(p.path, x.Name)
p.addNames(x.Elements)
if len(p.path) == 0 {
defer func() { p.path = p.path[:0] }()
p.path = append(p.path, x.Name)
}
// Top-level enum entry.
enum := &ast.Field{Label: name}
addComments(enum, 1, x.Comment, nil)
// Top-level enum values entry.
valueName := ast.NewIdent(name.Name + "_value")
valueName.NamePos = newSection
valueMap := &ast.StructLit{}
d := &ast.Field{Label: valueName, Value: valueMap}
// addComments(valueMap, 1, x.Comment, nil)
if strings.Contains(name.Name, "google") {
panic(name.Name)
}
p.file.Decls = append(p.file.Decls, enum, d)
numEnums := 0
for _, v := range x.Elements {
if _, ok := v.(*proto.EnumField); ok {
numEnums++
}
}
// The line comments for an enum field need to attach after the '|', which
// is only known at the next iteration.
var lastComment *proto.Comment
for i, v := range x.Elements {
switch y := v.(type) {
case *proto.EnumField:
// Add enum value to map
f := &ast.Field{
Label: p.stringLit(y.Position, y.Name),
Value: &ast.BasicLit{Value: strconv.Itoa(y.Integer)},
}
valueMap.Elts = append(valueMap.Elts, f)
// add to enum disjunction
value := p.stringLit(y.Position, y.Name)
var e ast.Expr = value
// Make the first value the default value.
if i > 0 {
value.ValuePos = newline
}
addComments(e, i, y.Comment, nil)
if enum.Value != nil {
e = &ast.BinaryExpr{X: enum.Value, Op: token.OR, Y: e}
if cg := comment(lastComment, false); cg != nil {
cg.Position = 2
e.AddComment(cg)
}
}
enum.Value = e
if y.Comment != nil {
lastComment = nil
addComments(f, 0, nil, y.InlineComment)
} else {
lastComment = y.InlineComment
}
// a := fmt.Sprintf("@protobuf(enum,name=%s)", y.Name)
// f.Attrs = append(f.Attrs, &ast.Attribute{Text: a})
}
}
addComments(enum.Value, 1, nil, lastComment)
}
// oneOf converts a Proto OneOf field to CUE. Note that Protobuf defines
// a oneOf to be at most one of the fields. Rather than making each field
// optional, we define oneOfs as all required fields, but add one more
// disjunction allowing no fields. This makes it easier to constrain the
// result to include at least one of the values.
func (p *protoConverter) oneOf(x *proto.Oneof) {
f := &ast.Field{
Label: p.ref(x.Position),
// TODO: Once we have closed structs, a oneOf is represented as a
// disjunction of empty structs and closed structs with required fields.
// For now we just specify the required fields. This is not correct
// but more practical.
// Value: &ast.StructLit{}, // Remove to make at least one required.
}
f.AddComment(comment(x.Comment, true))
p.file.Decls = append(p.file.Decls, f)
for _, v := range x.Elements {
s := &ast.StructLit{
// TODO: make this the default in the formatter.
Rbrace: token.Newline.Pos(),
}
switch x := v.(type) {
case *proto.OneOfField:
oneOf := p.parseField(s, 0, x.Field)
oneOf.Optional = token.NoPos
default:
p.messageField(s, 1, v)
}
var e ast.Expr = s
if f.Value != nil {
e = &ast.BinaryExpr{X: f.Value, Op: token.OR, Y: s}
}
f.Value = e
}
}
func (p *protoConverter) parseField(s *ast.StructLit, i int, x *proto.Field) *ast.Field {
defer func(saved []string) { p.path = saved }(p.path)
p.path = append(p.path, x.Name)
f := &ast.Field{}
addComments(f, i, x.Comment, x.InlineComment)
name := p.ident(x.Position, x.Name)
f.Label = name
typ := p.resolve(x.Position, x.Type, x.Options)
f.Value = p.toExpr(x.Position, typ)
s.Elts = append(s.Elts, f)
o := optionParser{message: s, field: f}
// body of @protobuf tag: sequence[,type][,name=<name>][,...]
o.tags += fmt.Sprint(x.Sequence)
if x.Type != typ {
o.tags += ",type=" + x.Type
}
if x.Name != name.Name {
o.tags += ",name=" + x.Name
}
o.parse(x.Options)
p.addTag(f, o.tags)
if !o.required {
f.Optional = token.NoSpace.Pos()
}
return f
}
type optionParser struct {
message *ast.StructLit
field *ast.Field
required bool
tags string
}
func (p *optionParser) parse(options []*proto.Option) {
// TODO: handle options
// - translate options to tags
// - interpret CUE options.
for _, o := range options {
switch o.Name {
case "(cue_opt).required":
p.required = true
// TODO: Dropping comments. Maybe add a dummy tag?
case "(cue.val)":
// TODO: set filename and base offset.
expr, err := parser.ParseExpr("", o.Constant.Source)
if err != nil {
failf(o.Position, "invalid cue.val value: %v", err)
}
// Any further checks will be done at the end.
constraint := &ast.Field{Label: p.field.Label, Value: expr}
addComments(constraint, 1, o.Comment, o.InlineComment)
p.message.Elts = append(p.message.Elts, constraint)
if !p.required {
constraint.Optional = token.NoSpace.Pos()
}
default:
// TODO: dropping comments. Maybe add dummy tag?
// TODO: should CUE support nested attributes?
source := o.Constant.SourceRepresentation()
p.tags += ","
switch source {
case "true":
p.tags += quoteOption(o.Name)
default:
p.tags += quoteOption(o.Name + "=" + source)
}
}
}
}
func quoteOption(s string) string {
needQuote := false
for _, r := range s {
if !unicode.In(r, unicode.L, unicode.N) {
needQuote = true
break
}
}
if !needQuote {
return s
}
if !strings.ContainsAny(s, `"\`) {
return strconv.Quote(s)
}
esc := `\#`
for strings.Contains(s, esc) {
esc += "#"
}
return esc[1:] + `"` + s + `"` + esc[1:]
}