diff --git a/vendor/google.golang.org/protobuf/internal/encoding/text/decode_token.go b/vendor/google.golang.org/protobuf/internal/encoding/text/decode_token.go
new file mode 100644
index 0000000..83d2b0d
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/text/decode_token.go
@@ -0,0 +1,373 @@
+// 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 text
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+
+	"google.golang.org/protobuf/internal/flags"
+)
+
+// Kind represents a token kind expressible in the textproto format.
+type Kind uint8
+
+// Kind values.
+const (
+	Invalid Kind = iota
+	EOF
+	Name   // Name indicates the field name.
+	Scalar // Scalar are scalar values, e.g. "string", 47, ENUM_LITERAL, true.
+	MessageOpen
+	MessageClose
+	ListOpen
+	ListClose
+
+	// comma and semi-colon are only for parsing in between values and should not be exposed.
+	comma
+	semicolon
+
+	// bof indicates beginning of file, which is the default token
+	// kind at the beginning of parsing.
+	bof = Invalid
+)
+
+func (t Kind) String() string {
+	switch t {
+	case Invalid:
+		return "<invalid>"
+	case EOF:
+		return "eof"
+	case Scalar:
+		return "scalar"
+	case Name:
+		return "name"
+	case MessageOpen:
+		return "{"
+	case MessageClose:
+		return "}"
+	case ListOpen:
+		return "["
+	case ListClose:
+		return "]"
+	case comma:
+		return ","
+	case semicolon:
+		return ";"
+	default:
+		return fmt.Sprintf("<invalid:%v>", uint8(t))
+	}
+}
+
+// NameKind represents different types of field names.
+type NameKind uint8
+
+// NameKind values.
+const (
+	IdentName NameKind = iota + 1
+	TypeName
+	FieldNumber
+)
+
+func (t NameKind) String() string {
+	switch t {
+	case IdentName:
+		return "IdentName"
+	case TypeName:
+		return "TypeName"
+	case FieldNumber:
+		return "FieldNumber"
+	default:
+		return fmt.Sprintf("<invalid:%v>", uint8(t))
+	}
+}
+
+// Bit mask in Token.attrs to indicate if a Name token is followed by the
+// separator char ':'. The field name separator char is optional for message
+// field or repeated message field, but required for all other types. Decoder
+// simply indicates whether a Name token is followed by separator or not.  It is
+// up to the prototext package to validate.
+const hasSeparator = 1 << 7
+
+// Scalar value types.
+const (
+	numberValue = iota + 1
+	stringValue
+	literalValue
+)
+
+// Bit mask in Token.numAttrs to indicate that the number is a negative.
+const isNegative = 1 << 7
+
+// Token provides a parsed token kind and value. Values are provided by the
+// different accessor methods.
+type Token struct {
+	// Kind of the Token object.
+	kind Kind
+	// attrs contains metadata for the following Kinds:
+	// Name: hasSeparator bit and one of NameKind.
+	// Scalar: one of numberValue, stringValue, literalValue.
+	attrs uint8
+	// numAttrs contains metadata for numberValue:
+	// - highest bit is whether negative or positive.
+	// - lower bits indicate one of numDec, numHex, numOct, numFloat.
+	numAttrs uint8
+	// pos provides the position of the token in the original input.
+	pos int
+	// raw bytes of the serialized token.
+	// This is a subslice into the original input.
+	raw []byte
+	// str contains parsed string for the following:
+	// - stringValue of Scalar kind
+	// - numberValue of Scalar kind
+	// - TypeName of Name kind
+	str string
+}
+
+// Kind returns the token kind.
+func (t Token) Kind() Kind {
+	return t.kind
+}
+
+// RawString returns the read value in string.
+func (t Token) RawString() string {
+	return string(t.raw)
+}
+
+// Pos returns the token position from the input.
+func (t Token) Pos() int {
+	return t.pos
+}
+
+// NameKind returns IdentName, TypeName or FieldNumber.
+// It panics if type is not Name.
+func (t Token) NameKind() NameKind {
+	if t.kind == Name {
+		return NameKind(t.attrs &^ hasSeparator)
+	}
+	panic(fmt.Sprintf("Token is not a Name type: %s", t.kind))
+}
+
+// HasSeparator returns true if the field name is followed by the separator char
+// ':', else false. It panics if type is not Name.
+func (t Token) HasSeparator() bool {
+	if t.kind == Name {
+		return t.attrs&hasSeparator != 0
+	}
+	panic(fmt.Sprintf("Token is not a Name type: %s", t.kind))
+}
+
+// IdentName returns the value for IdentName type.
+func (t Token) IdentName() string {
+	if t.kind == Name && t.attrs&uint8(IdentName) != 0 {
+		return string(t.raw)
+	}
+	panic(fmt.Sprintf("Token is not an IdentName: %s:%s", t.kind, NameKind(t.attrs&^hasSeparator)))
+}
+
+// TypeName returns the value for TypeName type.
+func (t Token) TypeName() string {
+	if t.kind == Name && t.attrs&uint8(TypeName) != 0 {
+		return t.str
+	}
+	panic(fmt.Sprintf("Token is not a TypeName: %s:%s", t.kind, NameKind(t.attrs&^hasSeparator)))
+}
+
+// FieldNumber returns the value for FieldNumber type. It returns a
+// non-negative int32 value. Caller will still need to validate for the correct
+// field number range.
+func (t Token) FieldNumber() int32 {
+	if t.kind != Name || t.attrs&uint8(FieldNumber) == 0 {
+		panic(fmt.Sprintf("Token is not a FieldNumber: %s:%s", t.kind, NameKind(t.attrs&^hasSeparator)))
+	}
+	// Following should not return an error as it had already been called right
+	// before this Token was constructed.
+	num, _ := strconv.ParseInt(string(t.raw), 10, 32)
+	return int32(num)
+}
+
+// String returns the string value for a Scalar type.
+func (t Token) String() (string, bool) {
+	if t.kind != Scalar || t.attrs != stringValue {
+		return "", false
+	}
+	return t.str, true
+}
+
+// Enum returns the literal value for a Scalar type for use as enum literals.
+func (t Token) Enum() (string, bool) {
+	if t.kind != Scalar || t.attrs != literalValue || (len(t.raw) > 0 && t.raw[0] == '-') {
+		return "", false
+	}
+	return string(t.raw), true
+}
+
+// Bool returns the bool value for a Scalar type.
+func (t Token) Bool() (bool, bool) {
+	if t.kind != Scalar {
+		return false, false
+	}
+	switch t.attrs {
+	case literalValue:
+		if b, ok := boolLits[string(t.raw)]; ok {
+			return b, true
+		}
+	case numberValue:
+		// Unsigned integer representation of 0 or 1 is permitted: 00, 0x0, 01,
+		// 0x1, etc.
+		n, err := strconv.ParseUint(t.str, 0, 64)
+		if err == nil {
+			switch n {
+			case 0:
+				return false, true
+			case 1:
+				return true, true
+			}
+		}
+	}
+	return false, false
+}
+
+// These exact boolean literals are the ones supported in C++.
+var boolLits = map[string]bool{
+	"t":     true,
+	"true":  true,
+	"True":  true,
+	"f":     false,
+	"false": false,
+	"False": false,
+}
+
+// Uint64 returns the uint64 value for a Scalar type.
+func (t Token) Uint64() (uint64, bool) {
+	if t.kind != Scalar || t.attrs != numberValue ||
+		t.numAttrs&isNegative > 0 || t.numAttrs&numFloat > 0 {
+		return 0, false
+	}
+	n, err := strconv.ParseUint(t.str, 0, 64)
+	if err != nil {
+		return 0, false
+	}
+	return n, true
+}
+
+// Uint32 returns the uint32 value for a Scalar type.
+func (t Token) Uint32() (uint32, bool) {
+	if t.kind != Scalar || t.attrs != numberValue ||
+		t.numAttrs&isNegative > 0 || t.numAttrs&numFloat > 0 {
+		return 0, false
+	}
+	n, err := strconv.ParseUint(t.str, 0, 32)
+	if err != nil {
+		return 0, false
+	}
+	return uint32(n), true
+}
+
+// Int64 returns the int64 value for a Scalar type.
+func (t Token) Int64() (int64, bool) {
+	if t.kind != Scalar || t.attrs != numberValue || t.numAttrs&numFloat > 0 {
+		return 0, false
+	}
+	if n, err := strconv.ParseInt(t.str, 0, 64); err == nil {
+		return n, true
+	}
+	// C++ accepts large positive hex numbers as negative values.
+	// This feature is here for proto1 backwards compatibility purposes.
+	if flags.ProtoLegacy && (t.numAttrs == numHex) {
+		if n, err := strconv.ParseUint(t.str, 0, 64); err == nil {
+			return int64(n), true
+		}
+	}
+	return 0, false
+}
+
+// Int32 returns the int32 value for a Scalar type.
+func (t Token) Int32() (int32, bool) {
+	if t.kind != Scalar || t.attrs != numberValue || t.numAttrs&numFloat > 0 {
+		return 0, false
+	}
+	if n, err := strconv.ParseInt(t.str, 0, 32); err == nil {
+		return int32(n), true
+	}
+	// C++ accepts large positive hex numbers as negative values.
+	// This feature is here for proto1 backwards compatibility purposes.
+	if flags.ProtoLegacy && (t.numAttrs == numHex) {
+		if n, err := strconv.ParseUint(t.str, 0, 32); err == nil {
+			return int32(n), true
+		}
+	}
+	return 0, false
+}
+
+// Float64 returns the float64 value for a Scalar type.
+func (t Token) Float64() (float64, bool) {
+	if t.kind != Scalar {
+		return 0, false
+	}
+	switch t.attrs {
+	case literalValue:
+		if f, ok := floatLits[strings.ToLower(string(t.raw))]; ok {
+			return f, true
+		}
+	case numberValue:
+		n, err := strconv.ParseFloat(t.str, 64)
+		if err == nil {
+			return n, true
+		}
+		nerr := err.(*strconv.NumError)
+		if nerr.Err == strconv.ErrRange {
+			return n, true
+		}
+	}
+	return 0, false
+}
+
+// Float32 returns the float32 value for a Scalar type.
+func (t Token) Float32() (float32, bool) {
+	if t.kind != Scalar {
+		return 0, false
+	}
+	switch t.attrs {
+	case literalValue:
+		if f, ok := floatLits[strings.ToLower(string(t.raw))]; ok {
+			return float32(f), true
+		}
+	case numberValue:
+		n, err := strconv.ParseFloat(t.str, 64)
+		if err == nil {
+			// Overflows are treated as (-)infinity.
+			return float32(n), true
+		}
+		nerr := err.(*strconv.NumError)
+		if nerr.Err == strconv.ErrRange {
+			return float32(n), true
+		}
+	}
+	return 0, false
+}
+
+// These are the supported float literals which C++ permits case-insensitive
+// variants of these.
+var floatLits = map[string]float64{
+	"nan":       math.NaN(),
+	"inf":       math.Inf(1),
+	"infinity":  math.Inf(1),
+	"-inf":      math.Inf(-1),
+	"-infinity": math.Inf(-1),
+}
+
+// TokenEquals returns true if given Tokens are equal, else false.
+func TokenEquals(x, y Token) bool {
+	return x.kind == y.kind &&
+		x.attrs == y.attrs &&
+		x.numAttrs == y.numAttrs &&
+		x.pos == y.pos &&
+		bytes.Equal(x.raw, y.raw) &&
+		x.str == y.str
+}