diff --git a/vendor/google.golang.org/protobuf/internal/encoding/text/decode.go b/vendor/google.golang.org/protobuf/internal/encoding/text/decode.go
new file mode 100644
index 0000000..eb10ea1
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/text/decode.go
@@ -0,0 +1,665 @@
+// 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"
+	"io"
+	"regexp"
+	"strconv"
+	"unicode/utf8"
+
+	"google.golang.org/protobuf/internal/errors"
+)
+
+// Decoder is a token-based textproto decoder.
+type Decoder struct {
+	// lastCall is last method called, either readCall or peekCall.
+	// Initial value is readCall.
+	lastCall call
+
+	// lastToken contains the last read token.
+	lastToken Token
+
+	// lastErr contains the last read error.
+	lastErr error
+
+	// openStack is a stack containing the byte characters for MessageOpen and
+	// ListOpen kinds. The top of stack represents the message or the list that
+	// the current token is nested in. An empty stack means the current token is
+	// at the top level message. The characters '{' and '<' both represent the
+	// MessageOpen kind.
+	openStack []byte
+
+	// orig is used in reporting line and column.
+	orig []byte
+	// in contains the unconsumed input.
+	in []byte
+}
+
+// NewDecoder returns a Decoder to read the given []byte.
+func NewDecoder(b []byte) *Decoder {
+	return &Decoder{orig: b, in: b}
+}
+
+// ErrUnexpectedEOF means that EOF was encountered in the middle of the input.
+var ErrUnexpectedEOF = errors.New("%v", io.ErrUnexpectedEOF)
+
+// call specifies which Decoder method was invoked.
+type call uint8
+
+const (
+	readCall call = iota
+	peekCall
+)
+
+// Peek looks ahead and returns the next token and error without advancing a read.
+func (d *Decoder) Peek() (Token, error) {
+	defer func() { d.lastCall = peekCall }()
+	if d.lastCall == readCall {
+		d.lastToken, d.lastErr = d.Read()
+	}
+	return d.lastToken, d.lastErr
+}
+
+// Read returns the next token.
+// It will return an error if there is no valid token.
+func (d *Decoder) Read() (Token, error) {
+	defer func() { d.lastCall = readCall }()
+	if d.lastCall == peekCall {
+		return d.lastToken, d.lastErr
+	}
+
+	tok, err := d.parseNext(d.lastToken.kind)
+	if err != nil {
+		return Token{}, err
+	}
+
+	switch tok.kind {
+	case comma, semicolon:
+		tok, err = d.parseNext(tok.kind)
+		if err != nil {
+			return Token{}, err
+		}
+	}
+	d.lastToken = tok
+	return tok, nil
+}
+
+const (
+	mismatchedFmt = "mismatched close character %q"
+	unexpectedFmt = "unexpected character %q"
+)
+
+// parseNext parses the next Token based on given last kind.
+func (d *Decoder) parseNext(lastKind Kind) (Token, error) {
+	// Trim leading spaces.
+	d.consume(0)
+	isEOF := false
+	if len(d.in) == 0 {
+		isEOF = true
+	}
+
+	switch lastKind {
+	case EOF:
+		return d.consumeToken(EOF, 0, 0), nil
+
+	case bof:
+		// Start of top level message. Next token can be EOF or Name.
+		if isEOF {
+			return d.consumeToken(EOF, 0, 0), nil
+		}
+		return d.parseFieldName()
+
+	case Name:
+		// Next token can be MessageOpen, ListOpen or Scalar.
+		if isEOF {
+			return Token{}, ErrUnexpectedEOF
+		}
+		switch ch := d.in[0]; ch {
+		case '{', '<':
+			d.pushOpenStack(ch)
+			return d.consumeToken(MessageOpen, 1, 0), nil
+		case '[':
+			d.pushOpenStack(ch)
+			return d.consumeToken(ListOpen, 1, 0), nil
+		default:
+			return d.parseScalar()
+		}
+
+	case Scalar:
+		openKind, closeCh := d.currentOpenKind()
+		switch openKind {
+		case bof:
+			// Top level message.
+			// 	Next token can be EOF, comma, semicolon or Name.
+			if isEOF {
+				return d.consumeToken(EOF, 0, 0), nil
+			}
+			switch d.in[0] {
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			case ';':
+				return d.consumeToken(semicolon, 1, 0), nil
+			default:
+				return d.parseFieldName()
+			}
+
+		case MessageOpen:
+			// Next token can be MessageClose, comma, semicolon or Name.
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case closeCh:
+				d.popOpenStack()
+				return d.consumeToken(MessageClose, 1, 0), nil
+			case otherCloseChar[closeCh]:
+				return Token{}, d.newSyntaxError(mismatchedFmt, ch)
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			case ';':
+				return d.consumeToken(semicolon, 1, 0), nil
+			default:
+				return d.parseFieldName()
+			}
+
+		case ListOpen:
+			// Next token can be ListClose or comma.
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case ']':
+				d.popOpenStack()
+				return d.consumeToken(ListClose, 1, 0), nil
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			default:
+				return Token{}, d.newSyntaxError(unexpectedFmt, ch)
+			}
+		}
+
+	case MessageOpen:
+		// Next token can be MessageClose or Name.
+		if isEOF {
+			return Token{}, ErrUnexpectedEOF
+		}
+		_, closeCh := d.currentOpenKind()
+		switch ch := d.in[0]; ch {
+		case closeCh:
+			d.popOpenStack()
+			return d.consumeToken(MessageClose, 1, 0), nil
+		case otherCloseChar[closeCh]:
+			return Token{}, d.newSyntaxError(mismatchedFmt, ch)
+		default:
+			return d.parseFieldName()
+		}
+
+	case MessageClose:
+		openKind, closeCh := d.currentOpenKind()
+		switch openKind {
+		case bof:
+			// Top level message.
+			// Next token can be EOF, comma, semicolon or Name.
+			if isEOF {
+				return d.consumeToken(EOF, 0, 0), nil
+			}
+			switch ch := d.in[0]; ch {
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			case ';':
+				return d.consumeToken(semicolon, 1, 0), nil
+			default:
+				return d.parseFieldName()
+			}
+
+		case MessageOpen:
+			// Next token can be MessageClose, comma, semicolon or Name.
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case closeCh:
+				d.popOpenStack()
+				return d.consumeToken(MessageClose, 1, 0), nil
+			case otherCloseChar[closeCh]:
+				return Token{}, d.newSyntaxError(mismatchedFmt, ch)
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			case ';':
+				return d.consumeToken(semicolon, 1, 0), nil
+			default:
+				return d.parseFieldName()
+			}
+
+		case ListOpen:
+			// Next token can be ListClose or comma
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case closeCh:
+				d.popOpenStack()
+				return d.consumeToken(ListClose, 1, 0), nil
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			default:
+				return Token{}, d.newSyntaxError(unexpectedFmt, ch)
+			}
+		}
+
+	case ListOpen:
+		// Next token can be ListClose, MessageStart or Scalar.
+		if isEOF {
+			return Token{}, ErrUnexpectedEOF
+		}
+		switch ch := d.in[0]; ch {
+		case ']':
+			d.popOpenStack()
+			return d.consumeToken(ListClose, 1, 0), nil
+		case '{', '<':
+			d.pushOpenStack(ch)
+			return d.consumeToken(MessageOpen, 1, 0), nil
+		default:
+			return d.parseScalar()
+		}
+
+	case ListClose:
+		openKind, closeCh := d.currentOpenKind()
+		switch openKind {
+		case bof:
+			// Top level message.
+			// Next token can be EOF, comma, semicolon or Name.
+			if isEOF {
+				return d.consumeToken(EOF, 0, 0), nil
+			}
+			switch ch := d.in[0]; ch {
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			case ';':
+				return d.consumeToken(semicolon, 1, 0), nil
+			default:
+				return d.parseFieldName()
+			}
+
+		case MessageOpen:
+			// Next token can be MessageClose, comma, semicolon or Name.
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case closeCh:
+				d.popOpenStack()
+				return d.consumeToken(MessageClose, 1, 0), nil
+			case otherCloseChar[closeCh]:
+				return Token{}, d.newSyntaxError(mismatchedFmt, ch)
+			case ',':
+				return d.consumeToken(comma, 1, 0), nil
+			case ';':
+				return d.consumeToken(semicolon, 1, 0), nil
+			default:
+				return d.parseFieldName()
+			}
+
+		default:
+			// It is not possible to have this case. Let it panic below.
+		}
+
+	case comma, semicolon:
+		openKind, closeCh := d.currentOpenKind()
+		switch openKind {
+		case bof:
+			// Top level message. Next token can be EOF or Name.
+			if isEOF {
+				return d.consumeToken(EOF, 0, 0), nil
+			}
+			return d.parseFieldName()
+
+		case MessageOpen:
+			// Next token can be MessageClose or Name.
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case closeCh:
+				d.popOpenStack()
+				return d.consumeToken(MessageClose, 1, 0), nil
+			case otherCloseChar[closeCh]:
+				return Token{}, d.newSyntaxError(mismatchedFmt, ch)
+			default:
+				return d.parseFieldName()
+			}
+
+		case ListOpen:
+			if lastKind == semicolon {
+				// It is not be possible to have this case as logic here
+				// should not have produced a semicolon Token when inside a
+				// list. Let it panic below.
+				break
+			}
+			// Next token can be MessageOpen or Scalar.
+			if isEOF {
+				return Token{}, ErrUnexpectedEOF
+			}
+			switch ch := d.in[0]; ch {
+			case '{', '<':
+				d.pushOpenStack(ch)
+				return d.consumeToken(MessageOpen, 1, 0), nil
+			default:
+				return d.parseScalar()
+			}
+		}
+	}
+
+	line, column := d.Position(len(d.orig) - len(d.in))
+	panic(fmt.Sprintf("Decoder.parseNext: bug at handling line %d:%d with lastKind=%v", line, column, lastKind))
+}
+
+var otherCloseChar = map[byte]byte{
+	'}': '>',
+	'>': '}',
+}
+
+// currentOpenKind indicates whether current position is inside a message, list
+// or top-level message by returning MessageOpen, ListOpen or bof respectively.
+// If the returned kind is either a MessageOpen or ListOpen, it also returns the
+// corresponding closing character.
+func (d *Decoder) currentOpenKind() (Kind, byte) {
+	if len(d.openStack) == 0 {
+		return bof, 0
+	}
+	openCh := d.openStack[len(d.openStack)-1]
+	switch openCh {
+	case '{':
+		return MessageOpen, '}'
+	case '<':
+		return MessageOpen, '>'
+	case '[':
+		return ListOpen, ']'
+	}
+	panic(fmt.Sprintf("Decoder: openStack contains invalid byte %s", string(openCh)))
+}
+
+func (d *Decoder) pushOpenStack(ch byte) {
+	d.openStack = append(d.openStack, ch)
+}
+
+func (d *Decoder) popOpenStack() {
+	d.openStack = d.openStack[:len(d.openStack)-1]
+}
+
+// parseFieldName parses field name and separator.
+func (d *Decoder) parseFieldName() (tok Token, err error) {
+	defer func() {
+		if err == nil && d.tryConsumeChar(':') {
+			tok.attrs |= hasSeparator
+		}
+	}()
+
+	// Extension or Any type URL.
+	if d.in[0] == '[' {
+		return d.parseTypeName()
+	}
+
+	// Identifier.
+	if size := parseIdent(d.in, false); size > 0 {
+		return d.consumeToken(Name, size, uint8(IdentName)), nil
+	}
+
+	// Field number. Identify if input is a valid number that is not negative
+	// and is decimal integer within 32-bit range.
+	if num := parseNumber(d.in); num.size > 0 {
+		if !num.neg && num.kind == numDec {
+			if _, err := strconv.ParseInt(string(d.in[:num.size]), 10, 32); err == nil {
+				return d.consumeToken(Name, num.size, uint8(FieldNumber)), nil
+			}
+		}
+		return Token{}, d.newSyntaxError("invalid field number: %s", d.in[:num.size])
+	}
+
+	return Token{}, d.newSyntaxError("invalid field name: %s", errRegexp.Find(d.in))
+}
+
+// parseTypeName parses Any type URL or extension field name. The name is
+// enclosed in [ and ] characters. The C++ parser does not handle many legal URL
+// strings. This implementation is more liberal and allows for the pattern
+// ^[-_a-zA-Z0-9]+([./][-_a-zA-Z0-9]+)*`). Whitespaces and comments are allowed
+// in between [ ], '.', '/' and the sub names.
+func (d *Decoder) parseTypeName() (Token, error) {
+	startPos := len(d.orig) - len(d.in)
+	// Use alias s to advance first in order to use d.in for error handling.
+	// Caller already checks for [ as first character.
+	s := consume(d.in[1:], 0)
+	if len(s) == 0 {
+		return Token{}, ErrUnexpectedEOF
+	}
+
+	var name []byte
+	for len(s) > 0 && isTypeNameChar(s[0]) {
+		name = append(name, s[0])
+		s = s[1:]
+	}
+	s = consume(s, 0)
+
+	var closed bool
+	for len(s) > 0 && !closed {
+		switch {
+		case s[0] == ']':
+			s = s[1:]
+			closed = true
+
+		case s[0] == '/', s[0] == '.':
+			if len(name) > 0 && (name[len(name)-1] == '/' || name[len(name)-1] == '.') {
+				return Token{}, d.newSyntaxError("invalid type URL/extension field name: %s",
+					d.orig[startPos:len(d.orig)-len(s)+1])
+			}
+			name = append(name, s[0])
+			s = s[1:]
+			s = consume(s, 0)
+			for len(s) > 0 && isTypeNameChar(s[0]) {
+				name = append(name, s[0])
+				s = s[1:]
+			}
+			s = consume(s, 0)
+
+		default:
+			return Token{}, d.newSyntaxError(
+				"invalid type URL/extension field name: %s", d.orig[startPos:len(d.orig)-len(s)+1])
+		}
+	}
+
+	if !closed {
+		return Token{}, ErrUnexpectedEOF
+	}
+
+	// First character cannot be '.'. Last character cannot be '.' or '/'.
+	size := len(name)
+	if size == 0 || name[0] == '.' || name[size-1] == '.' || name[size-1] == '/' {
+		return Token{}, d.newSyntaxError("invalid type URL/extension field name: %s",
+			d.orig[startPos:len(d.orig)-len(s)])
+	}
+
+	d.in = s
+	endPos := len(d.orig) - len(d.in)
+	d.consume(0)
+
+	return Token{
+		kind:  Name,
+		attrs: uint8(TypeName),
+		pos:   startPos,
+		raw:   d.orig[startPos:endPos],
+		str:   string(name),
+	}, nil
+}
+
+func isTypeNameChar(b byte) bool {
+	return (b == '-' || b == '_' ||
+		('0' <= b && b <= '9') ||
+		('a' <= b && b <= 'z') ||
+		('A' <= b && b <= 'Z'))
+}
+
+func isWhiteSpace(b byte) bool {
+	switch b {
+	case ' ', '\n', '\r', '\t':
+		return true
+	default:
+		return false
+	}
+}
+
+// parseIdent parses an unquoted proto identifier and returns size.
+// If allowNeg is true, it allows '-' to be the first character in the
+// identifier. This is used when parsing literal values like -infinity, etc.
+// Regular expression matches an identifier: `^[_a-zA-Z][_a-zA-Z0-9]*`
+func parseIdent(input []byte, allowNeg bool) int {
+	var size int
+
+	s := input
+	if len(s) == 0 {
+		return 0
+	}
+
+	if allowNeg && s[0] == '-' {
+		s = s[1:]
+		size++
+		if len(s) == 0 {
+			return 0
+		}
+	}
+
+	switch {
+	case s[0] == '_',
+		'a' <= s[0] && s[0] <= 'z',
+		'A' <= s[0] && s[0] <= 'Z':
+		s = s[1:]
+		size++
+	default:
+		return 0
+	}
+
+	for len(s) > 0 && (s[0] == '_' ||
+		'a' <= s[0] && s[0] <= 'z' ||
+		'A' <= s[0] && s[0] <= 'Z' ||
+		'0' <= s[0] && s[0] <= '9') {
+		s = s[1:]
+		size++
+	}
+
+	if len(s) > 0 && !isDelim(s[0]) {
+		return 0
+	}
+
+	return size
+}
+
+// parseScalar parses for a string, literal or number value.
+func (d *Decoder) parseScalar() (Token, error) {
+	if d.in[0] == '"' || d.in[0] == '\'' {
+		return d.parseStringValue()
+	}
+
+	if tok, ok := d.parseLiteralValue(); ok {
+		return tok, nil
+	}
+
+	if tok, ok := d.parseNumberValue(); ok {
+		return tok, nil
+	}
+
+	return Token{}, d.newSyntaxError("invalid scalar value: %s", errRegexp.Find(d.in))
+}
+
+// parseLiteralValue parses a literal value. A literal value is used for
+// bools, special floats and enums. This function simply identifies that the
+// field value is a literal.
+func (d *Decoder) parseLiteralValue() (Token, bool) {
+	size := parseIdent(d.in, true)
+	if size == 0 {
+		return Token{}, false
+	}
+	return d.consumeToken(Scalar, size, literalValue), true
+}
+
+// consumeToken constructs a Token for given Kind from d.in and consumes given
+// size-length from it.
+func (d *Decoder) consumeToken(kind Kind, size int, attrs uint8) Token {
+	// Important to compute raw and pos before consuming.
+	tok := Token{
+		kind:  kind,
+		attrs: attrs,
+		pos:   len(d.orig) - len(d.in),
+		raw:   d.in[:size],
+	}
+	d.consume(size)
+	return tok
+}
+
+// newSyntaxError returns a syntax error with line and column information for
+// current position.
+func (d *Decoder) newSyntaxError(f string, x ...interface{}) error {
+	e := errors.New(f, x...)
+	line, column := d.Position(len(d.orig) - len(d.in))
+	return errors.New("syntax error (line %d:%d): %v", line, column, e)
+}
+
+// Position returns line and column number of given index of the original input.
+// It will panic if index is out of range.
+func (d *Decoder) Position(idx int) (line int, column int) {
+	b := d.orig[:idx]
+	line = bytes.Count(b, []byte("\n")) + 1
+	if i := bytes.LastIndexByte(b, '\n'); i >= 0 {
+		b = b[i+1:]
+	}
+	column = utf8.RuneCount(b) + 1 // ignore multi-rune characters
+	return line, column
+}
+
+func (d *Decoder) tryConsumeChar(c byte) bool {
+	if len(d.in) > 0 && d.in[0] == c {
+		d.consume(1)
+		return true
+	}
+	return false
+}
+
+// consume consumes n bytes of input and any subsequent whitespace or comments.
+func (d *Decoder) consume(n int) {
+	d.in = consume(d.in, n)
+	return
+}
+
+// consume consumes n bytes of input and any subsequent whitespace or comments.
+func consume(b []byte, n int) []byte {
+	b = b[n:]
+	for len(b) > 0 {
+		switch b[0] {
+		case ' ', '\n', '\r', '\t':
+			b = b[1:]
+		case '#':
+			if i := bytes.IndexByte(b, '\n'); i >= 0 {
+				b = b[i+len("\n"):]
+			} else {
+				b = nil
+			}
+		default:
+			return b
+		}
+	}
+	return b
+}
+
+// Any sequence that looks like a non-delimiter (for error reporting).
+var errRegexp = regexp.MustCompile(`^([-+._a-zA-Z0-9\/]+|.)`)
+
+// isDelim returns true if given byte is a delimiter character.
+func isDelim(c byte) bool {
+	return !(c == '-' || c == '+' || c == '.' || c == '_' ||
+		('a' <= c && c <= 'z') ||
+		('A' <= c && c <= 'Z') ||
+		('0' <= c && c <= '9'))
+}