schnutibox/vendor/github.com/jhump/protoreflect/dynamic/text.go
Marvin Steadfast ae35d9ab41
Some checks failed
continuous-integration/drone/push Build is failing
uses buf for compiling proto files and implements the server service
2021-05-05 11:14:17 +02:00

1178 lines
30 KiB
Go

package dynamic
// Marshalling and unmarshalling of dynamic messages to/from proto's standard text format
import (
"bytes"
"fmt"
"io"
"math"
"reflect"
"sort"
"strconv"
"strings"
"text/scanner"
"unicode"
"github.com/golang/protobuf/proto"
"github.com/golang/protobuf/protoc-gen-go/descriptor"
"github.com/jhump/protoreflect/codec"
"github.com/jhump/protoreflect/desc"
)
// MarshalText serializes this message to bytes in the standard text format,
// returning an error if the operation fails. The resulting bytes will be a
// valid UTF8 string.
//
// This method uses a compact form: no newlines, and spaces between field
// identifiers and values are elided.
func (m *Message) MarshalText() ([]byte, error) {
var b indentBuffer
b.indentCount = -1 // no indentation
if err := m.marshalText(&b); err != nil {
return nil, err
}
return b.Bytes(), nil
}
// MarshalTextIndent serializes this message to bytes in the standard text
// format, returning an error if the operation fails. The resulting bytes will
// be a valid UTF8 string.
//
// This method uses a "pretty-printed" form, with each field on its own line and
// spaces between field identifiers and values.
func (m *Message) MarshalTextIndent() ([]byte, error) {
var b indentBuffer
b.indent = " " // TODO: option for indent?
if err := m.marshalText(&b); err != nil {
return nil, err
}
return b.Bytes(), nil
}
func (m *Message) marshalText(b *indentBuffer) error {
// TODO: option for emitting extended Any format?
first := true
// first the known fields
for _, tag := range m.knownFieldTags() {
itag := int32(tag)
v := m.values[itag]
fd := m.FindFieldDescriptor(itag)
if fd.IsMap() {
md := fd.GetMessageType()
kfd := md.FindFieldByNumber(1)
vfd := md.FindFieldByNumber(2)
mp := v.(map[interface{}]interface{})
keys := make([]interface{}, 0, len(mp))
for k := range mp {
keys = append(keys, k)
}
sort.Sort(sortable(keys))
for _, mk := range keys {
mv := mp[mk]
err := b.maybeNext(&first)
if err != nil {
return err
}
err = marshalKnownFieldMapEntryText(b, fd, kfd, mk, vfd, mv)
if err != nil {
return err
}
}
} else if fd.IsRepeated() {
sl := v.([]interface{})
for _, slv := range sl {
err := b.maybeNext(&first)
if err != nil {
return err
}
err = marshalKnownFieldText(b, fd, slv)
if err != nil {
return err
}
}
} else {
err := b.maybeNext(&first)
if err != nil {
return err
}
err = marshalKnownFieldText(b, fd, v)
if err != nil {
return err
}
}
}
// then the unknown fields
for _, tag := range m.unknownFieldTags() {
itag := int32(tag)
ufs := m.unknownFields[itag]
for _, uf := range ufs {
err := b.maybeNext(&first)
if err != nil {
return err
}
_, err = fmt.Fprintf(b, "%d", tag)
if err != nil {
return err
}
if uf.Encoding == proto.WireStartGroup {
err = b.WriteByte('{')
if err != nil {
return err
}
err = b.start()
if err != nil {
return err
}
in := codec.NewBuffer(uf.Contents)
err = marshalUnknownGroupText(b, in, true)
if err != nil {
return err
}
err = b.end()
if err != nil {
return err
}
err = b.WriteByte('}')
if err != nil {
return err
}
} else {
err = b.sep()
if err != nil {
return err
}
if uf.Encoding == proto.WireBytes {
err = writeString(b, string(uf.Contents))
if err != nil {
return err
}
} else {
_, err = b.WriteString(strconv.FormatUint(uf.Value, 10))
if err != nil {
return err
}
}
}
}
}
return nil
}
func marshalKnownFieldMapEntryText(b *indentBuffer, fd *desc.FieldDescriptor, kfd *desc.FieldDescriptor, mk interface{}, vfd *desc.FieldDescriptor, mv interface{}) error {
var name string
if fd.IsExtension() {
name = fmt.Sprintf("[%s]", fd.GetFullyQualifiedName())
} else {
name = fd.GetName()
}
_, err := b.WriteString(name)
if err != nil {
return err
}
err = b.sep()
if err != nil {
return err
}
err = b.WriteByte('<')
if err != nil {
return err
}
err = b.start()
if err != nil {
return err
}
err = marshalKnownFieldText(b, kfd, mk)
if err != nil {
return err
}
err = b.next()
if err != nil {
return err
}
if !isNil(mv) {
err = marshalKnownFieldText(b, vfd, mv)
if err != nil {
return err
}
}
err = b.end()
if err != nil {
return err
}
return b.WriteByte('>')
}
func marshalKnownFieldText(b *indentBuffer, fd *desc.FieldDescriptor, v interface{}) error {
group := fd.GetType() == descriptor.FieldDescriptorProto_TYPE_GROUP
if group {
var name string
if fd.IsExtension() {
name = fmt.Sprintf("[%s]", fd.GetMessageType().GetFullyQualifiedName())
} else {
name = fd.GetMessageType().GetName()
}
_, err := b.WriteString(name)
if err != nil {
return err
}
} else {
var name string
if fd.IsExtension() {
name = fmt.Sprintf("[%s]", fd.GetFullyQualifiedName())
} else {
name = fd.GetName()
}
_, err := b.WriteString(name)
if err != nil {
return err
}
err = b.sep()
if err != nil {
return err
}
}
rv := reflect.ValueOf(v)
switch rv.Kind() {
case reflect.Int32, reflect.Int64:
ed := fd.GetEnumType()
if ed != nil {
n := int32(rv.Int())
vd := ed.FindValueByNumber(n)
if vd == nil {
_, err := b.WriteString(strconv.FormatInt(rv.Int(), 10))
return err
} else {
_, err := b.WriteString(vd.GetName())
return err
}
} else {
_, err := b.WriteString(strconv.FormatInt(rv.Int(), 10))
return err
}
case reflect.Uint32, reflect.Uint64:
_, err := b.WriteString(strconv.FormatUint(rv.Uint(), 10))
return err
case reflect.Float32, reflect.Float64:
f := rv.Float()
var str string
if math.IsNaN(f) {
str = "nan"
} else if math.IsInf(f, 1) {
str = "inf"
} else if math.IsInf(f, -1) {
str = "-inf"
} else {
var bits int
if rv.Kind() == reflect.Float32 {
bits = 32
} else {
bits = 64
}
str = strconv.FormatFloat(rv.Float(), 'g', -1, bits)
}
_, err := b.WriteString(str)
return err
case reflect.Bool:
_, err := b.WriteString(strconv.FormatBool(rv.Bool()))
return err
case reflect.Slice:
return writeString(b, string(rv.Bytes()))
case reflect.String:
return writeString(b, rv.String())
default:
var err error
if group {
err = b.WriteByte('{')
} else {
err = b.WriteByte('<')
}
if err != nil {
return err
}
err = b.start()
if err != nil {
return err
}
// must be a message
if dm, ok := v.(*Message); ok {
err = dm.marshalText(b)
if err != nil {
return err
}
} else {
err = proto.CompactText(b, v.(proto.Message))
if err != nil {
return err
}
}
err = b.end()
if err != nil {
return err
}
if group {
return b.WriteByte('}')
} else {
return b.WriteByte('>')
}
}
}
// writeString writes a string in the protocol buffer text format.
// It is similar to strconv.Quote except we don't use Go escape sequences,
// we treat the string as a byte sequence, and we use octal escapes.
// These differences are to maintain interoperability with the other
// languages' implementations of the text format.
func writeString(b *indentBuffer, s string) error {
// use WriteByte here to get any needed indent
if err := b.WriteByte('"'); err != nil {
return err
}
// Loop over the bytes, not the runes.
for i := 0; i < len(s); i++ {
var err error
// Divergence from C++: we don't escape apostrophes.
// There's no need to escape them, and the C++ parser
// copes with a naked apostrophe.
switch c := s[i]; c {
case '\n':
_, err = b.WriteString("\\n")
case '\r':
_, err = b.WriteString("\\r")
case '\t':
_, err = b.WriteString("\\t")
case '"':
_, err = b.WriteString("\\\"")
case '\\':
_, err = b.WriteString("\\\\")
default:
if c >= 0x20 && c < 0x7f {
err = b.WriteByte(c)
} else {
_, err = fmt.Fprintf(b, "\\%03o", c)
}
}
if err != nil {
return err
}
}
return b.WriteByte('"')
}
func marshalUnknownGroupText(b *indentBuffer, in *codec.Buffer, topLevel bool) error {
first := true
for {
if in.EOF() {
if topLevel {
return nil
}
// this is a nested message: we are expecting an end-group tag, not EOF!
return io.ErrUnexpectedEOF
}
tag, wireType, err := in.DecodeTagAndWireType()
if err != nil {
return err
}
if wireType == proto.WireEndGroup {
return nil
}
err = b.maybeNext(&first)
if err != nil {
return err
}
_, err = fmt.Fprintf(b, "%d", tag)
if err != nil {
return err
}
if wireType == proto.WireStartGroup {
err = b.WriteByte('{')
if err != nil {
return err
}
err = b.start()
if err != nil {
return err
}
err = marshalUnknownGroupText(b, in, false)
if err != nil {
return err
}
err = b.end()
if err != nil {
return err
}
err = b.WriteByte('}')
if err != nil {
return err
}
continue
} else {
err = b.sep()
if err != nil {
return err
}
if wireType == proto.WireBytes {
contents, err := in.DecodeRawBytes(false)
if err != nil {
return err
}
err = writeString(b, string(contents))
if err != nil {
return err
}
} else {
var v uint64
switch wireType {
case proto.WireVarint:
v, err = in.DecodeVarint()
case proto.WireFixed32:
v, err = in.DecodeFixed32()
case proto.WireFixed64:
v, err = in.DecodeFixed64()
default:
return proto.ErrInternalBadWireType
}
if err != nil {
return err
}
_, err = b.WriteString(strconv.FormatUint(v, 10))
if err != nil {
return err
}
}
}
}
}
// UnmarshalText de-serializes the message that is present, in text format, in
// the given bytes into this message. It first resets the current message. It
// returns an error if the given bytes do not contain a valid encoding of this
// message type in the standard text format
func (m *Message) UnmarshalText(text []byte) error {
m.Reset()
if err := m.UnmarshalMergeText(text); err != nil {
return err
}
return m.Validate()
}
// UnmarshalMergeText de-serializes the message that is present, in text format,
// in the given bytes into this message. Unlike UnmarshalText, it does not first
// reset the message, instead merging the data in the given bytes into the
// existing data in this message.
func (m *Message) UnmarshalMergeText(text []byte) error {
return m.unmarshalText(newReader(text), tokenEOF)
}
func (m *Message) unmarshalText(tr *txtReader, end tokenType) error {
for {
tok := tr.next()
if tok.tokTyp == end {
return nil
}
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
}
var fd *desc.FieldDescriptor
var extendedAnyType *desc.MessageDescriptor
if tok.tokTyp == tokenInt {
// tag number (indicates unknown field)
tag, err := strconv.ParseInt(tok.val.(string), 10, 32)
if err != nil {
return err
}
itag := int32(tag)
fd = m.FindFieldDescriptor(itag)
if fd == nil {
// can't parse the value w/out field descriptor, so skip it
tok = tr.next()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
} else if tok.tokTyp == tokenOpenBrace {
if err := skipMessageText(tr, true); err != nil {
return err
}
} else if tok.tokTyp == tokenColon {
if err := skipFieldValueText(tr); err != nil {
return err
}
} else {
return textError(tok, "Expecting a colon ':' or brace '{'; instead got %q", tok.txt)
}
tok = tr.peek()
if tok.tokTyp.IsSep() {
tr.next() // consume separator
}
continue
}
} else {
fieldName, err := unmarshalFieldNameText(tr, tok)
if err != nil {
return err
}
fd = m.FindFieldDescriptorByName(fieldName)
if fd == nil {
// See if it's a group name
for _, field := range m.md.GetFields() {
if field.GetType() == descriptor.FieldDescriptorProto_TYPE_GROUP && field.GetMessageType().GetName() == fieldName {
fd = field
break
}
}
if fd == nil {
// maybe this is an extended Any
if m.md.GetFullyQualifiedName() == "google.protobuf.Any" && fieldName[0] == '[' && strings.Contains(fieldName, "/") {
// strip surrounding "[" and "]" and extract type name from URL
typeUrl := fieldName[1 : len(fieldName)-1]
mname := typeUrl
if slash := strings.LastIndex(mname, "/"); slash >= 0 {
mname = mname[slash+1:]
}
// TODO: add a way to weave an AnyResolver to this point
extendedAnyType = findMessageDescriptor(mname, m.md.GetFile())
if extendedAnyType == nil {
return textError(tok, "could not parse Any with unknown type URL %q", fieldName)
}
// field 1 is "type_url"
typeUrlField := m.md.FindFieldByNumber(1)
if err := m.TrySetField(typeUrlField, typeUrl); err != nil {
return err
}
} else {
// TODO: add a flag to just ignore unrecognized field names
return textError(tok, "%q is not a recognized field name of %q", fieldName, m.md.GetFullyQualifiedName())
}
}
}
}
tok = tr.next()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
}
if extendedAnyType != nil {
// consume optional colon; make sure this is a "start message" token
if tok.tokTyp == tokenColon {
tok = tr.next()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
}
}
if tok.tokTyp.EndToken() == tokenError {
return textError(tok, "Expecting a '<' or '{'; instead got %q", tok.txt)
}
// TODO: use mf.NewMessage and, if not a dynamic message, use proto.UnmarshalText to unmarshal it
g := m.mf.NewDynamicMessage(extendedAnyType)
if err := g.unmarshalText(tr, tok.tokTyp.EndToken()); err != nil {
return err
}
// now we marshal the message to bytes and store in the Any
b, err := g.Marshal()
if err != nil {
return err
}
// field 2 is "value"
anyValueField := m.md.FindFieldByNumber(2)
if err := m.TrySetField(anyValueField, b); err != nil {
return err
}
} else if (fd.GetType() == descriptor.FieldDescriptorProto_TYPE_GROUP ||
fd.GetType() == descriptor.FieldDescriptorProto_TYPE_MESSAGE) &&
tok.tokTyp.EndToken() != tokenError {
// TODO: use mf.NewMessage and, if not a dynamic message, use proto.UnmarshalText to unmarshal it
g := m.mf.NewDynamicMessage(fd.GetMessageType())
if err := g.unmarshalText(tr, tok.tokTyp.EndToken()); err != nil {
return err
}
if fd.IsRepeated() {
if err := m.TryAddRepeatedField(fd, g); err != nil {
return err
}
} else {
if err := m.TrySetField(fd, g); err != nil {
return err
}
}
} else {
if tok.tokTyp != tokenColon {
return textError(tok, "Expecting a colon ':'; instead got %q", tok.txt)
}
if err := m.unmarshalFieldValueText(fd, tr); err != nil {
return err
}
}
tok = tr.peek()
if tok.tokTyp.IsSep() {
tr.next() // consume separator
}
}
}
func findMessageDescriptor(name string, fd *desc.FileDescriptor) *desc.MessageDescriptor {
md := findMessageInTransitiveDeps(name, fd, map[*desc.FileDescriptor]struct{}{})
if md == nil {
// couldn't find it; see if we have this message linked in
md, _ = desc.LoadMessageDescriptor(name)
}
return md
}
func findMessageInTransitiveDeps(name string, fd *desc.FileDescriptor, seen map[*desc.FileDescriptor]struct{}) *desc.MessageDescriptor {
if _, ok := seen[fd]; ok {
// already checked this file
return nil
}
seen[fd] = struct{}{}
md := fd.FindMessage(name)
if md != nil {
return md
}
// not in this file so recursively search its deps
for _, dep := range fd.GetDependencies() {
md = findMessageInTransitiveDeps(name, dep, seen)
if md != nil {
return md
}
}
// couldn't find it
return nil
}
func textError(tok *token, format string, args ...interface{}) error {
var msg string
if tok.tokTyp == tokenError {
msg = tok.val.(error).Error()
} else {
msg = fmt.Sprintf(format, args...)
}
return fmt.Errorf("line %d, col %d: %s", tok.pos.Line, tok.pos.Column, msg)
}
type setFunction func(*Message, *desc.FieldDescriptor, interface{}) error
func (m *Message) unmarshalFieldValueText(fd *desc.FieldDescriptor, tr *txtReader) error {
var set setFunction
if fd.IsRepeated() {
set = (*Message).addRepeatedField
} else {
set = mergeField
}
tok := tr.peek()
if tok.tokTyp == tokenOpenBracket {
tr.next() // consume tok
for {
if err := m.unmarshalFieldElementText(fd, tr, set); err != nil {
return err
}
tok = tr.peek()
if tok.tokTyp == tokenCloseBracket {
tr.next() // consume tok
return nil
} else if tok.tokTyp.IsSep() {
tr.next() // consume separator
}
}
}
return m.unmarshalFieldElementText(fd, tr, set)
}
func (m *Message) unmarshalFieldElementText(fd *desc.FieldDescriptor, tr *txtReader, set setFunction) error {
tok := tr.next()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
}
var expected string
switch fd.GetType() {
case descriptor.FieldDescriptorProto_TYPE_BOOL:
if tok.tokTyp == tokenIdent {
if tok.val.(string) == "true" {
return set(m, fd, true)
} else if tok.val.(string) == "false" {
return set(m, fd, false)
}
}
expected = "boolean value"
case descriptor.FieldDescriptorProto_TYPE_BYTES:
if tok.tokTyp == tokenString {
return set(m, fd, []byte(tok.val.(string)))
}
expected = "bytes string value"
case descriptor.FieldDescriptorProto_TYPE_STRING:
if tok.tokTyp == tokenString {
return set(m, fd, tok.val)
}
expected = "string value"
case descriptor.FieldDescriptorProto_TYPE_FLOAT:
switch tok.tokTyp {
case tokenFloat:
return set(m, fd, float32(tok.val.(float64)))
case tokenInt:
if f, err := strconv.ParseFloat(tok.val.(string), 32); err != nil {
return err
} else {
return set(m, fd, float32(f))
}
case tokenIdent:
ident := strings.ToLower(tok.val.(string))
if ident == "inf" {
return set(m, fd, float32(math.Inf(1)))
} else if ident == "nan" {
return set(m, fd, float32(math.NaN()))
}
case tokenMinus:
peeked := tr.peek()
if peeked.tokTyp == tokenIdent {
ident := strings.ToLower(peeked.val.(string))
if ident == "inf" {
tr.next() // consume peeked token
return set(m, fd, float32(math.Inf(-1)))
}
}
}
expected = "float value"
case descriptor.FieldDescriptorProto_TYPE_DOUBLE:
switch tok.tokTyp {
case tokenFloat:
return set(m, fd, tok.val)
case tokenInt:
if f, err := strconv.ParseFloat(tok.val.(string), 64); err != nil {
return err
} else {
return set(m, fd, f)
}
case tokenIdent:
ident := strings.ToLower(tok.val.(string))
if ident == "inf" {
return set(m, fd, math.Inf(1))
} else if ident == "nan" {
return set(m, fd, math.NaN())
}
case tokenMinus:
peeked := tr.peek()
if peeked.tokTyp == tokenIdent {
ident := strings.ToLower(peeked.val.(string))
if ident == "inf" {
tr.next() // consume peeked token
return set(m, fd, math.Inf(-1))
}
}
}
expected = "float value"
case descriptor.FieldDescriptorProto_TYPE_INT32,
descriptor.FieldDescriptorProto_TYPE_SINT32,
descriptor.FieldDescriptorProto_TYPE_SFIXED32:
if tok.tokTyp == tokenInt {
if i, err := strconv.ParseInt(tok.val.(string), 10, 32); err != nil {
return err
} else {
return set(m, fd, int32(i))
}
}
expected = "int value"
case descriptor.FieldDescriptorProto_TYPE_INT64,
descriptor.FieldDescriptorProto_TYPE_SINT64,
descriptor.FieldDescriptorProto_TYPE_SFIXED64:
if tok.tokTyp == tokenInt {
if i, err := strconv.ParseInt(tok.val.(string), 10, 64); err != nil {
return err
} else {
return set(m, fd, i)
}
}
expected = "int value"
case descriptor.FieldDescriptorProto_TYPE_UINT32,
descriptor.FieldDescriptorProto_TYPE_FIXED32:
if tok.tokTyp == tokenInt {
if i, err := strconv.ParseUint(tok.val.(string), 10, 32); err != nil {
return err
} else {
return set(m, fd, uint32(i))
}
}
expected = "unsigned int value"
case descriptor.FieldDescriptorProto_TYPE_UINT64,
descriptor.FieldDescriptorProto_TYPE_FIXED64:
if tok.tokTyp == tokenInt {
if i, err := strconv.ParseUint(tok.val.(string), 10, 64); err != nil {
return err
} else {
return set(m, fd, i)
}
}
expected = "unsigned int value"
case descriptor.FieldDescriptorProto_TYPE_ENUM:
if tok.tokTyp == tokenIdent {
// TODO: add a flag to just ignore unrecognized enum value names?
vd := fd.GetEnumType().FindValueByName(tok.val.(string))
if vd != nil {
return set(m, fd, vd.GetNumber())
}
} else if tok.tokTyp == tokenInt {
if i, err := strconv.ParseInt(tok.val.(string), 10, 32); err != nil {
return err
} else {
return set(m, fd, int32(i))
}
}
expected = fmt.Sprintf("enum %s value", fd.GetEnumType().GetFullyQualifiedName())
case descriptor.FieldDescriptorProto_TYPE_MESSAGE,
descriptor.FieldDescriptorProto_TYPE_GROUP:
endTok := tok.tokTyp.EndToken()
if endTok != tokenError {
dm := m.mf.NewDynamicMessage(fd.GetMessageType())
if err := dm.unmarshalText(tr, endTok); err != nil {
return err
}
// TODO: ideally we would use mf.NewMessage and, if not a dynamic message, use
// proto package to unmarshal it. But the text parser isn't particularly amenable
// to that, so we instead convert a dynamic message to a generated one if the
// known-type registry knows about the generated type...
var ktr *KnownTypeRegistry
if m.mf != nil {
ktr = m.mf.ktr
}
pm := ktr.CreateIfKnown(fd.GetMessageType().GetFullyQualifiedName())
if pm != nil {
if err := dm.ConvertTo(pm); err != nil {
return set(m, fd, pm)
}
}
return set(m, fd, dm)
}
expected = fmt.Sprintf("message %s value", fd.GetMessageType().GetFullyQualifiedName())
default:
return fmt.Errorf("field %q of message %q has unrecognized type: %v", fd.GetFullyQualifiedName(), m.md.GetFullyQualifiedName(), fd.GetType())
}
// if we get here, token was wrong type; create error message
var article string
if strings.Contains("aieou", expected[0:1]) {
article = "an"
} else {
article = "a"
}
return textError(tok, "Expecting %s %s; got %q", article, expected, tok.txt)
}
func unmarshalFieldNameText(tr *txtReader, tok *token) (string, error) {
if tok.tokTyp == tokenOpenBracket || tok.tokTyp == tokenOpenParen {
// extension name
var closeType tokenType
var closeChar string
if tok.tokTyp == tokenOpenBracket {
closeType = tokenCloseBracket
closeChar = "close bracket ']'"
} else {
closeType = tokenCloseParen
closeChar = "close paren ')'"
}
// must be followed by an identifier
idents := make([]string, 0, 1)
for {
tok = tr.next()
if tok.tokTyp == tokenEOF {
return "", io.ErrUnexpectedEOF
} else if tok.tokTyp != tokenIdent {
return "", textError(tok, "Expecting an identifier; instead got %q", tok.txt)
}
idents = append(idents, tok.val.(string))
// and then close bracket/paren, or "/" to keep adding URL elements to name
tok = tr.next()
if tok.tokTyp == tokenEOF {
return "", io.ErrUnexpectedEOF
} else if tok.tokTyp == closeType {
break
} else if tok.tokTyp != tokenSlash {
return "", textError(tok, "Expecting a %s; instead got %q", closeChar, tok.txt)
}
}
return "[" + strings.Join(idents, "/") + "]", nil
} else if tok.tokTyp == tokenIdent {
// normal field name
return tok.val.(string), nil
} else {
return "", textError(tok, "Expecting an identifier or tag number; instead got %q", tok.txt)
}
}
func skipFieldNameText(tr *txtReader) error {
tok := tr.next()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
} else if tok.tokTyp == tokenInt || tok.tokTyp == tokenIdent {
return nil
} else {
_, err := unmarshalFieldNameText(tr, tok)
return err
}
}
func skipFieldValueText(tr *txtReader) error {
tok := tr.peek()
if tok.tokTyp == tokenOpenBracket {
tr.next() // consume tok
for {
if err := skipFieldElementText(tr); err != nil {
return err
}
tok = tr.peek()
if tok.tokTyp == tokenCloseBracket {
tr.next() // consume tok
return nil
} else if tok.tokTyp.IsSep() {
tr.next() // consume separator
}
}
}
return skipFieldElementText(tr)
}
func skipFieldElementText(tr *txtReader) error {
tok := tr.next()
switch tok.tokTyp {
case tokenEOF:
return io.ErrUnexpectedEOF
case tokenInt, tokenFloat, tokenString, tokenIdent:
return nil
case tokenOpenAngle:
return skipMessageText(tr, false)
default:
return textError(tok, "Expecting an angle bracket '<' or a value; instead got %q", tok.txt)
}
}
func skipMessageText(tr *txtReader, isGroup bool) error {
for {
tok := tr.peek()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
} else if isGroup && tok.tokTyp == tokenCloseBrace {
return nil
} else if !isGroup && tok.tokTyp == tokenCloseAngle {
return nil
}
// field name or tag
if err := skipFieldNameText(tr); err != nil {
return err
}
// field value
tok = tr.next()
if tok.tokTyp == tokenEOF {
return io.ErrUnexpectedEOF
} else if tok.tokTyp == tokenOpenBrace {
if err := skipMessageText(tr, true); err != nil {
return err
}
} else if tok.tokTyp == tokenColon {
if err := skipFieldValueText(tr); err != nil {
return err
}
} else {
return textError(tok, "Expecting a colon ':' or brace '{'; instead got %q", tok.txt)
}
tok = tr.peek()
if tok.tokTyp.IsSep() {
tr.next() // consume separator
}
}
}
type tokenType int
const (
tokenError tokenType = iota
tokenEOF
tokenIdent
tokenString
tokenInt
tokenFloat
tokenColon
tokenComma
tokenSemiColon
tokenOpenBrace
tokenCloseBrace
tokenOpenBracket
tokenCloseBracket
tokenOpenAngle
tokenCloseAngle
tokenOpenParen
tokenCloseParen
tokenSlash
tokenMinus
)
func (t tokenType) IsSep() bool {
return t == tokenComma || t == tokenSemiColon
}
func (t tokenType) EndToken() tokenType {
switch t {
case tokenOpenAngle:
return tokenCloseAngle
case tokenOpenBrace:
return tokenCloseBrace
default:
return tokenError
}
}
type token struct {
tokTyp tokenType
val interface{}
txt string
pos scanner.Position
}
type txtReader struct {
scanner scanner.Scanner
peeked token
havePeeked bool
}
func newReader(text []byte) *txtReader {
sc := scanner.Scanner{}
sc.Init(bytes.NewReader(text))
sc.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanFloats | scanner.ScanChars |
scanner.ScanStrings | scanner.ScanComments | scanner.SkipComments
// identifiers are same restrictions as Go identifiers, except we also allow dots since
// we accept fully-qualified names
sc.IsIdentRune = func(ch rune, i int) bool {
return ch == '_' || unicode.IsLetter(ch) ||
(i > 0 && unicode.IsDigit(ch)) ||
(i > 0 && ch == '.')
}
// ignore errors; we handle them if/when we see malformed tokens
sc.Error = func(s *scanner.Scanner, msg string) {}
return &txtReader{scanner: sc}
}
func (p *txtReader) peek() *token {
if p.havePeeked {
return &p.peeked
}
t := p.scanner.Scan()
if t == scanner.EOF {
p.peeked.tokTyp = tokenEOF
p.peeked.val = nil
p.peeked.txt = ""
p.peeked.pos = p.scanner.Position
} else if err := p.processToken(t, p.scanner.TokenText(), p.scanner.Position); err != nil {
p.peeked.tokTyp = tokenError
p.peeked.val = err
}
p.havePeeked = true
return &p.peeked
}
func (p *txtReader) processToken(t rune, text string, pos scanner.Position) error {
p.peeked.pos = pos
p.peeked.txt = text
switch t {
case scanner.Ident:
p.peeked.tokTyp = tokenIdent
p.peeked.val = text
case scanner.Int:
p.peeked.tokTyp = tokenInt
p.peeked.val = text // can't parse the number because we don't know if it's signed or unsigned
case scanner.Float:
p.peeked.tokTyp = tokenFloat
var err error
if p.peeked.val, err = strconv.ParseFloat(text, 64); err != nil {
return err
}
case scanner.Char, scanner.String:
p.peeked.tokTyp = tokenString
var err error
if p.peeked.val, err = strconv.Unquote(text); err != nil {
return err
}
case '-': // unary minus, for negative ints and floats
ch := p.scanner.Peek()
if ch < '0' || ch > '9' {
p.peeked.tokTyp = tokenMinus
p.peeked.val = '-'
} else {
t := p.scanner.Scan()
if t == scanner.EOF {
return io.ErrUnexpectedEOF
} else if t == scanner.Float {
p.peeked.tokTyp = tokenFloat
text += p.scanner.TokenText()
p.peeked.txt = text
var err error
if p.peeked.val, err = strconv.ParseFloat(text, 64); err != nil {
p.peeked.pos = p.scanner.Position
return err
}
} else if t == scanner.Int {
p.peeked.tokTyp = tokenInt
text += p.scanner.TokenText()
p.peeked.txt = text
p.peeked.val = text // can't parse the number because we don't know if it's signed or unsigned
} else {
p.peeked.pos = p.scanner.Position
return fmt.Errorf("expecting an int or float but got %q", p.scanner.TokenText())
}
}
case ':':
p.peeked.tokTyp = tokenColon
p.peeked.val = ':'
case ',':
p.peeked.tokTyp = tokenComma
p.peeked.val = ','
case ';':
p.peeked.tokTyp = tokenSemiColon
p.peeked.val = ';'
case '{':
p.peeked.tokTyp = tokenOpenBrace
p.peeked.val = '{'
case '}':
p.peeked.tokTyp = tokenCloseBrace
p.peeked.val = '}'
case '<':
p.peeked.tokTyp = tokenOpenAngle
p.peeked.val = '<'
case '>':
p.peeked.tokTyp = tokenCloseAngle
p.peeked.val = '>'
case '[':
p.peeked.tokTyp = tokenOpenBracket
p.peeked.val = '['
case ']':
p.peeked.tokTyp = tokenCloseBracket
p.peeked.val = ']'
case '(':
p.peeked.tokTyp = tokenOpenParen
p.peeked.val = '('
case ')':
p.peeked.tokTyp = tokenCloseParen
p.peeked.val = ')'
case '/':
// only allowed to separate URL components in expanded Any format
p.peeked.tokTyp = tokenSlash
p.peeked.val = '/'
default:
return fmt.Errorf("invalid character: %c", t)
}
return nil
}
func (p *txtReader) next() *token {
t := p.peek()
if t.tokTyp != tokenEOF && t.tokTyp != tokenError {
p.havePeeked = false
}
return t
}