diff --git a/vendor/google.golang.org/protobuf/internal/encoding/json/decode.go b/vendor/google.golang.org/protobuf/internal/encoding/json/decode.go
new file mode 100644
index 0000000..b13fd29
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/json/decode.go
@@ -0,0 +1,340 @@
+// 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 json
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"regexp"
+	"unicode/utf8"
+
+	"google.golang.org/protobuf/internal/errors"
+)
+
+// call specifies which Decoder method was invoked.
+type call uint8
+
+const (
+	readCall call = iota
+	peekCall
+)
+
+const unexpectedFmt = "unexpected token %s"
+
+// ErrUnexpectedEOF means that EOF was encountered in the middle of the input.
+var ErrUnexpectedEOF = errors.New("%v", io.ErrUnexpectedEOF)
+
+// Decoder is a token-based JSON 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 ObjectOpen and ArrayOpen values. The
+	// top of stack represents the object or the array the current value is
+	// directly located in.
+	openStack []Kind
+
+	// 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}
+}
+
+// Peek looks ahead and returns the next token kind 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 JSON token.
+// It will return an error if there is no valid token.
+func (d *Decoder) Read() (Token, error) {
+	const scalar = Null | Bool | Number | String
+
+	defer func() { d.lastCall = readCall }()
+	if d.lastCall == peekCall {
+		return d.lastToken, d.lastErr
+	}
+
+	tok, err := d.parseNext()
+	if err != nil {
+		return Token{}, err
+	}
+
+	switch tok.kind {
+	case EOF:
+		if len(d.openStack) != 0 ||
+			d.lastToken.kind&scalar|ObjectClose|ArrayClose == 0 {
+			return Token{}, ErrUnexpectedEOF
+		}
+
+	case Null:
+		if !d.isValueNext() {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+
+	case Bool, Number:
+		if !d.isValueNext() {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+
+	case String:
+		if d.isValueNext() {
+			break
+		}
+		// This string token should only be for a field name.
+		if d.lastToken.kind&(ObjectOpen|comma) == 0 {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+		if len(d.in) == 0 {
+			return Token{}, ErrUnexpectedEOF
+		}
+		if c := d.in[0]; c != ':' {
+			return Token{}, d.newSyntaxError(d.currPos(), `unexpected character %s, missing ":" after field name`, string(c))
+		}
+		tok.kind = Name
+		d.consume(1)
+
+	case ObjectOpen, ArrayOpen:
+		if !d.isValueNext() {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+		d.openStack = append(d.openStack, tok.kind)
+
+	case ObjectClose:
+		if len(d.openStack) == 0 ||
+			d.lastToken.kind == comma ||
+			d.openStack[len(d.openStack)-1] != ObjectOpen {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+		d.openStack = d.openStack[:len(d.openStack)-1]
+
+	case ArrayClose:
+		if len(d.openStack) == 0 ||
+			d.lastToken.kind == comma ||
+			d.openStack[len(d.openStack)-1] != ArrayOpen {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+		d.openStack = d.openStack[:len(d.openStack)-1]
+
+	case comma:
+		if len(d.openStack) == 0 ||
+			d.lastToken.kind&(scalar|ObjectClose|ArrayClose) == 0 {
+			return Token{}, d.newSyntaxError(tok.pos, unexpectedFmt, tok.RawString())
+		}
+	}
+
+	// Update d.lastToken only after validating token to be in the right sequence.
+	d.lastToken = tok
+
+	if d.lastToken.kind == comma {
+		return d.Read()
+	}
+	return tok, nil
+}
+
+// Any sequence that looks like a non-delimiter (for error reporting).
+var errRegexp = regexp.MustCompile(`^([-+._a-zA-Z0-9]{1,32}|.)`)
+
+// parseNext parses for the next JSON token. It returns a Token object for
+// different types, except for Name. It does not handle whether the next token
+// is in a valid sequence or not.
+func (d *Decoder) parseNext() (Token, error) {
+	// Trim leading spaces.
+	d.consume(0)
+
+	in := d.in
+	if len(in) == 0 {
+		return d.consumeToken(EOF, 0), nil
+	}
+
+	switch in[0] {
+	case 'n':
+		if n := matchWithDelim("null", in); n != 0 {
+			return d.consumeToken(Null, n), nil
+		}
+
+	case 't':
+		if n := matchWithDelim("true", in); n != 0 {
+			return d.consumeBoolToken(true, n), nil
+		}
+
+	case 'f':
+		if n := matchWithDelim("false", in); n != 0 {
+			return d.consumeBoolToken(false, n), nil
+		}
+
+	case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+		if n, ok := parseNumber(in); ok {
+			return d.consumeToken(Number, n), nil
+		}
+
+	case '"':
+		s, n, err := d.parseString(in)
+		if err != nil {
+			return Token{}, err
+		}
+		return d.consumeStringToken(s, n), nil
+
+	case '{':
+		return d.consumeToken(ObjectOpen, 1), nil
+
+	case '}':
+		return d.consumeToken(ObjectClose, 1), nil
+
+	case '[':
+		return d.consumeToken(ArrayOpen, 1), nil
+
+	case ']':
+		return d.consumeToken(ArrayClose, 1), nil
+
+	case ',':
+		return d.consumeToken(comma, 1), nil
+	}
+	return Token{}, d.newSyntaxError(d.currPos(), "invalid value %s", errRegexp.Find(in))
+}
+
+// newSyntaxError returns an error with line and column information useful for
+// syntax errors.
+func (d *Decoder) newSyntaxError(pos int, f string, x ...interface{}) error {
+	e := errors.New(f, x...)
+	line, column := d.Position(pos)
+	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
+}
+
+// currPos returns the current index position of d.in from d.orig.
+func (d *Decoder) currPos() int {
+	return len(d.orig) - len(d.in)
+}
+
+// matchWithDelim matches s with the input b and verifies that the match
+// terminates with a delimiter of some form (e.g., r"[^-+_.a-zA-Z0-9]").
+// As a special case, EOF is considered a delimiter. It returns the length of s
+// if there is a match, else 0.
+func matchWithDelim(s string, b []byte) int {
+	if !bytes.HasPrefix(b, []byte(s)) {
+		return 0
+	}
+
+	n := len(s)
+	if n < len(b) && isNotDelim(b[n]) {
+		return 0
+	}
+	return n
+}
+
+// isNotDelim returns true if given byte is a not delimiter character.
+func isNotDelim(c byte) bool {
+	return (c == '-' || c == '+' || c == '.' || c == '_' ||
+		('a' <= c && c <= 'z') ||
+		('A' <= c && c <= 'Z') ||
+		('0' <= c && c <= '9'))
+}
+
+// consume consumes n bytes of input and any subsequent whitespace.
+func (d *Decoder) consume(n int) {
+	d.in = d.in[n:]
+	for len(d.in) > 0 {
+		switch d.in[0] {
+		case ' ', '\n', '\r', '\t':
+			d.in = d.in[1:]
+		default:
+			return
+		}
+	}
+}
+
+// isValueNext returns true if next type should be a JSON value: Null,
+// Number, String or Bool.
+func (d *Decoder) isValueNext() bool {
+	if len(d.openStack) == 0 {
+		return d.lastToken.kind == 0
+	}
+
+	start := d.openStack[len(d.openStack)-1]
+	switch start {
+	case ObjectOpen:
+		return d.lastToken.kind&Name != 0
+	case ArrayOpen:
+		return d.lastToken.kind&(ArrayOpen|comma) != 0
+	}
+	panic(fmt.Sprintf(
+		"unreachable logic in Decoder.isValueNext, lastToken.kind: %v, openStack: %v",
+		d.lastToken.kind, start))
+}
+
+// consumeToken constructs a Token for given Kind with raw value derived from
+// current d.in and given size, and consumes the given size-lenght of it.
+func (d *Decoder) consumeToken(kind Kind, size int) Token {
+	tok := Token{
+		kind: kind,
+		raw:  d.in[:size],
+		pos:  len(d.orig) - len(d.in),
+	}
+	d.consume(size)
+	return tok
+}
+
+// consumeBoolToken constructs a Token for a Bool kind with raw value derived from
+// current d.in and given size.
+func (d *Decoder) consumeBoolToken(b bool, size int) Token {
+	tok := Token{
+		kind: Bool,
+		raw:  d.in[:size],
+		pos:  len(d.orig) - len(d.in),
+		boo:  b,
+	}
+	d.consume(size)
+	return tok
+}
+
+// consumeStringToken constructs a Token for a String kind with raw value derived
+// from current d.in and given size.
+func (d *Decoder) consumeStringToken(s string, size int) Token {
+	tok := Token{
+		kind: String,
+		raw:  d.in[:size],
+		pos:  len(d.orig) - len(d.in),
+		str:  s,
+	}
+	d.consume(size)
+	return tok
+}
+
+// Clone returns a copy of the Decoder for use in reading ahead the next JSON
+// object, array or other values without affecting current Decoder.
+func (d *Decoder) Clone() *Decoder {
+	ret := *d
+	ret.openStack = append([]Kind(nil), ret.openStack...)
+	return &ret
+}
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/json/decode_number.go b/vendor/google.golang.org/protobuf/internal/encoding/json/decode_number.go
new file mode 100644
index 0000000..2999d71
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/json/decode_number.go
@@ -0,0 +1,254 @@
+// 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 json
+
+import (
+	"bytes"
+	"strconv"
+)
+
+// parseNumber reads the given []byte for a valid JSON number. If it is valid,
+// it returns the number of bytes.  Parsing logic follows the definition in
+// https://tools.ietf.org/html/rfc7159#section-6, and is based off
+// encoding/json.isValidNumber function.
+func parseNumber(input []byte) (int, bool) {
+	var n int
+
+	s := input
+	if len(s) == 0 {
+		return 0, false
+	}
+
+	// Optional -
+	if s[0] == '-' {
+		s = s[1:]
+		n++
+		if len(s) == 0 {
+			return 0, false
+		}
+	}
+
+	// Digits
+	switch {
+	case s[0] == '0':
+		s = s[1:]
+		n++
+
+	case '1' <= s[0] && s[0] <= '9':
+		s = s[1:]
+		n++
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+			n++
+		}
+
+	default:
+		return 0, false
+	}
+
+	// . followed by 1 or more digits.
+	if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
+		s = s[2:]
+		n += 2
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+			n++
+		}
+	}
+
+	// e or E followed by an optional - or + and
+	// 1 or more digits.
+	if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
+		s = s[1:]
+		n++
+		if s[0] == '+' || s[0] == '-' {
+			s = s[1:]
+			n++
+			if len(s) == 0 {
+				return 0, false
+			}
+		}
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+			n++
+		}
+	}
+
+	// Check that next byte is a delimiter or it is at the end.
+	if n < len(input) && isNotDelim(input[n]) {
+		return 0, false
+	}
+
+	return n, true
+}
+
+// numberParts is the result of parsing out a valid JSON number. It contains
+// the parts of a number. The parts are used for integer conversion.
+type numberParts struct {
+	neg  bool
+	intp []byte
+	frac []byte
+	exp  []byte
+}
+
+// parseNumber constructs numberParts from given []byte. The logic here is
+// similar to consumeNumber above with the difference of having to construct
+// numberParts. The slice fields in numberParts are subslices of the input.
+func parseNumberParts(input []byte) (numberParts, bool) {
+	var neg bool
+	var intp []byte
+	var frac []byte
+	var exp []byte
+
+	s := input
+	if len(s) == 0 {
+		return numberParts{}, false
+	}
+
+	// Optional -
+	if s[0] == '-' {
+		neg = true
+		s = s[1:]
+		if len(s) == 0 {
+			return numberParts{}, false
+		}
+	}
+
+	// Digits
+	switch {
+	case s[0] == '0':
+		// Skip first 0 and no need to store.
+		s = s[1:]
+
+	case '1' <= s[0] && s[0] <= '9':
+		intp = s
+		n := 1
+		s = s[1:]
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+			n++
+		}
+		intp = intp[:n]
+
+	default:
+		return numberParts{}, false
+	}
+
+	// . followed by 1 or more digits.
+	if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
+		frac = s[1:]
+		n := 1
+		s = s[2:]
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+			n++
+		}
+		frac = frac[:n]
+	}
+
+	// e or E followed by an optional - or + and
+	// 1 or more digits.
+	if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
+		s = s[1:]
+		exp = s
+		n := 0
+		if s[0] == '+' || s[0] == '-' {
+			s = s[1:]
+			n++
+			if len(s) == 0 {
+				return numberParts{}, false
+			}
+		}
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+			n++
+		}
+		exp = exp[:n]
+	}
+
+	return numberParts{
+		neg:  neg,
+		intp: intp,
+		frac: bytes.TrimRight(frac, "0"), // Remove unnecessary 0s to the right.
+		exp:  exp,
+	}, true
+}
+
+// normalizeToIntString returns an integer string in normal form without the
+// E-notation for given numberParts. It will return false if it is not an
+// integer or if the exponent exceeds than max/min int value.
+func normalizeToIntString(n numberParts) (string, bool) {
+	intpSize := len(n.intp)
+	fracSize := len(n.frac)
+
+	if intpSize == 0 && fracSize == 0 {
+		return "0", true
+	}
+
+	var exp int
+	if len(n.exp) > 0 {
+		i, err := strconv.ParseInt(string(n.exp), 10, 32)
+		if err != nil {
+			return "", false
+		}
+		exp = int(i)
+	}
+
+	var num []byte
+	if exp >= 0 {
+		// For positive E, shift fraction digits into integer part and also pad
+		// with zeroes as needed.
+
+		// If there are more digits in fraction than the E value, then the
+		// number is not an integer.
+		if fracSize > exp {
+			return "", false
+		}
+
+		// Make sure resulting digits are within max value limit to avoid
+		// unnecessarily constructing a large byte slice that may simply fail
+		// later on.
+		const maxDigits = 20 // Max uint64 value has 20 decimal digits.
+		if intpSize+exp > maxDigits {
+			return "", false
+		}
+
+		// Set cap to make a copy of integer part when appended.
+		num = n.intp[:len(n.intp):len(n.intp)]
+		num = append(num, n.frac...)
+		for i := 0; i < exp-fracSize; i++ {
+			num = append(num, '0')
+		}
+	} else {
+		// For negative E, shift digits in integer part out.
+
+		// If there are fractions, then the number is not an integer.
+		if fracSize > 0 {
+			return "", false
+		}
+
+		// index is where the decimal point will be after adjusting for negative
+		// exponent.
+		index := intpSize + exp
+		if index < 0 {
+			return "", false
+		}
+
+		num = n.intp
+		// If any of the digits being shifted to the right of the decimal point
+		// is non-zero, then the number is not an integer.
+		for i := index; i < intpSize; i++ {
+			if num[i] != '0' {
+				return "", false
+			}
+		}
+		num = num[:index]
+	}
+
+	if n.neg {
+		return "-" + string(num), true
+	}
+	return string(num), true
+}
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/json/decode_string.go b/vendor/google.golang.org/protobuf/internal/encoding/json/decode_string.go
new file mode 100644
index 0000000..f7fea7d
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/json/decode_string.go
@@ -0,0 +1,91 @@
+// 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 json
+
+import (
+	"strconv"
+	"unicode"
+	"unicode/utf16"
+	"unicode/utf8"
+
+	"google.golang.org/protobuf/internal/strs"
+)
+
+func (d *Decoder) parseString(in []byte) (string, int, error) {
+	in0 := in
+	if len(in) == 0 {
+		return "", 0, ErrUnexpectedEOF
+	}
+	if in[0] != '"' {
+		return "", 0, d.newSyntaxError(d.currPos(), "invalid character %q at start of string", in[0])
+	}
+	in = in[1:]
+	i := indexNeedEscapeInBytes(in)
+	in, out := in[i:], in[:i:i] // set cap to prevent mutations
+	for len(in) > 0 {
+		switch r, n := utf8.DecodeRune(in); {
+		case r == utf8.RuneError && n == 1:
+			return "", 0, d.newSyntaxError(d.currPos(), "invalid UTF-8 in string")
+		case r < ' ':
+			return "", 0, d.newSyntaxError(d.currPos(), "invalid character %q in string", r)
+		case r == '"':
+			in = in[1:]
+			n := len(in0) - len(in)
+			return string(out), n, nil
+		case r == '\\':
+			if len(in) < 2 {
+				return "", 0, ErrUnexpectedEOF
+			}
+			switch r := in[1]; r {
+			case '"', '\\', '/':
+				in, out = in[2:], append(out, r)
+			case 'b':
+				in, out = in[2:], append(out, '\b')
+			case 'f':
+				in, out = in[2:], append(out, '\f')
+			case 'n':
+				in, out = in[2:], append(out, '\n')
+			case 'r':
+				in, out = in[2:], append(out, '\r')
+			case 't':
+				in, out = in[2:], append(out, '\t')
+			case 'u':
+				if len(in) < 6 {
+					return "", 0, ErrUnexpectedEOF
+				}
+				v, err := strconv.ParseUint(string(in[2:6]), 16, 16)
+				if err != nil {
+					return "", 0, d.newSyntaxError(d.currPos(), "invalid escape code %q in string", in[:6])
+				}
+				in = in[6:]
+
+				r := rune(v)
+				if utf16.IsSurrogate(r) {
+					if len(in) < 6 {
+						return "", 0, ErrUnexpectedEOF
+					}
+					v, err := strconv.ParseUint(string(in[2:6]), 16, 16)
+					r = utf16.DecodeRune(r, rune(v))
+					if in[0] != '\\' || in[1] != 'u' ||
+						r == unicode.ReplacementChar || err != nil {
+						return "", 0, d.newSyntaxError(d.currPos(), "invalid escape code %q in string", in[:6])
+					}
+					in = in[6:]
+				}
+				out = append(out, string(r)...)
+			default:
+				return "", 0, d.newSyntaxError(d.currPos(), "invalid escape code %q in string", in[:2])
+			}
+		default:
+			i := indexNeedEscapeInBytes(in[n:])
+			in, out = in[n+i:], append(out, in[:n+i]...)
+		}
+	}
+	return "", 0, ErrUnexpectedEOF
+}
+
+// indexNeedEscapeInBytes returns the index of the character that needs
+// escaping. If no characters need escaping, this returns the input length.
+func indexNeedEscapeInBytes(b []byte) int { return indexNeedEscapeInString(strs.UnsafeString(b)) }
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/json/decode_token.go b/vendor/google.golang.org/protobuf/internal/encoding/json/decode_token.go
new file mode 100644
index 0000000..50578d6
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/json/decode_token.go
@@ -0,0 +1,192 @@
+// 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 json
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+)
+
+// Kind represents a token kind expressible in the JSON format.
+type Kind uint16
+
+const (
+	Invalid Kind = (1 << iota) / 2
+	EOF
+	Null
+	Bool
+	Number
+	String
+	Name
+	ObjectOpen
+	ObjectClose
+	ArrayOpen
+	ArrayClose
+
+	// comma is only for parsing in between tokens and
+	// does not need to be exported.
+	comma
+)
+
+func (k Kind) String() string {
+	switch k {
+	case EOF:
+		return "eof"
+	case Null:
+		return "null"
+	case Bool:
+		return "bool"
+	case Number:
+		return "number"
+	case String:
+		return "string"
+	case ObjectOpen:
+		return "{"
+	case ObjectClose:
+		return "}"
+	case Name:
+		return "name"
+	case ArrayOpen:
+		return "["
+	case ArrayClose:
+		return "]"
+	case comma:
+		return ","
+	}
+	return "<invalid>"
+}
+
+// Token provides a parsed token kind and value.
+//
+// Values are provided by the difference accessor methods. The accessor methods
+// Name, Bool, and ParsedString will panic if called on the wrong kind. There
+// are different accessor methods for the Number kind for converting to the
+// appropriate Go numeric type and those methods have the ok return value.
+type Token struct {
+	// Token kind.
+	kind Kind
+	// 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
+	// boo is parsed boolean value.
+	boo bool
+	// str is parsed string value.
+	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
+}
+
+// Name returns the object name if token is Name, else it panics.
+func (t Token) Name() string {
+	if t.kind == Name {
+		return t.str
+	}
+	panic(fmt.Sprintf("Token is not a Name: %v", t.RawString()))
+}
+
+// Bool returns the bool value if token kind is Bool, else it panics.
+func (t Token) Bool() bool {
+	if t.kind == Bool {
+		return t.boo
+	}
+	panic(fmt.Sprintf("Token is not a Bool: %v", t.RawString()))
+}
+
+// ParsedString returns the string value for a JSON string token or the read
+// value in string if token is not a string.
+func (t Token) ParsedString() string {
+	if t.kind == String {
+		return t.str
+	}
+	panic(fmt.Sprintf("Token is not a String: %v", t.RawString()))
+}
+
+// Float returns the floating-point number if token kind is Number.
+//
+// The floating-point precision is specified by the bitSize parameter: 32 for
+// float32 or 64 for float64. If bitSize=32, the result still has type float64,
+// but it will be convertible to float32 without changing its value. It will
+// return false if the number exceeds the floating point limits for given
+// bitSize.
+func (t Token) Float(bitSize int) (float64, bool) {
+	if t.kind != Number {
+		return 0, false
+	}
+	f, err := strconv.ParseFloat(t.RawString(), bitSize)
+	if err != nil {
+		return 0, false
+	}
+	return f, true
+}
+
+// Int returns the signed integer number if token is Number.
+//
+// The given bitSize specifies the integer type that the result must fit into.
+// It returns false if the number is not an integer value or if the result
+// exceeds the limits for given bitSize.
+func (t Token) Int(bitSize int) (int64, bool) {
+	s, ok := t.getIntStr()
+	if !ok {
+		return 0, false
+	}
+	n, err := strconv.ParseInt(s, 10, bitSize)
+	if err != nil {
+		return 0, false
+	}
+	return n, true
+}
+
+// Uint returns the signed integer number if token is Number.
+//
+// The given bitSize specifies the unsigned integer type that the result must
+// fit into. It returns false if the number is not an unsigned integer value
+// or if the result exceeds the limits for given bitSize.
+func (t Token) Uint(bitSize int) (uint64, bool) {
+	s, ok := t.getIntStr()
+	if !ok {
+		return 0, false
+	}
+	n, err := strconv.ParseUint(s, 10, bitSize)
+	if err != nil {
+		return 0, false
+	}
+	return n, true
+}
+
+func (t Token) getIntStr() (string, bool) {
+	if t.kind != Number {
+		return "", false
+	}
+	parts, ok := parseNumberParts(t.raw)
+	if !ok {
+		return "", false
+	}
+	return normalizeToIntString(parts)
+}
+
+// TokenEquals returns true if given Tokens are equal, else false.
+func TokenEquals(x, y Token) bool {
+	return x.kind == y.kind &&
+		x.pos == y.pos &&
+		bytes.Equal(x.raw, y.raw) &&
+		x.boo == y.boo &&
+		x.str == y.str
+}
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/json/encode.go b/vendor/google.golang.org/protobuf/internal/encoding/json/encode.go
new file mode 100644
index 0000000..fbdf348
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/encoding/json/encode.go
@@ -0,0 +1,276 @@
+// 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 json
+
+import (
+	"math"
+	"math/bits"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+
+	"google.golang.org/protobuf/internal/detrand"
+	"google.golang.org/protobuf/internal/errors"
+)
+
+// kind represents an encoding type.
+type kind uint8
+
+const (
+	_ kind = (1 << iota) / 2
+	name
+	scalar
+	objectOpen
+	objectClose
+	arrayOpen
+	arrayClose
+)
+
+// Encoder provides methods to write out JSON constructs and values. The user is
+// responsible for producing valid sequences of JSON constructs and values.
+type Encoder struct {
+	indent   string
+	lastKind kind
+	indents  []byte
+	out      []byte
+}
+
+// NewEncoder returns an Encoder.
+//
+// If indent is a non-empty string, it causes every entry for an Array or Object
+// to be preceded by the indent and trailed by a newline.
+func NewEncoder(indent string) (*Encoder, error) {
+	e := &Encoder{}
+	if len(indent) > 0 {
+		if strings.Trim(indent, " \t") != "" {
+			return nil, errors.New("indent may only be composed of space or tab characters")
+		}
+		e.indent = indent
+	}
+	return e, nil
+}
+
+// Bytes returns the content of the written bytes.
+func (e *Encoder) Bytes() []byte {
+	return e.out
+}
+
+// WriteNull writes out the null value.
+func (e *Encoder) WriteNull() {
+	e.prepareNext(scalar)
+	e.out = append(e.out, "null"...)
+}
+
+// WriteBool writes out the given boolean value.
+func (e *Encoder) WriteBool(b bool) {
+	e.prepareNext(scalar)
+	if b {
+		e.out = append(e.out, "true"...)
+	} else {
+		e.out = append(e.out, "false"...)
+	}
+}
+
+// WriteString writes out the given string in JSON string value. Returns error
+// if input string contains invalid UTF-8.
+func (e *Encoder) WriteString(s string) error {
+	e.prepareNext(scalar)
+	var err error
+	if e.out, err = appendString(e.out, s); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Sentinel error used for indicating invalid UTF-8.
+var errInvalidUTF8 = errors.New("invalid UTF-8")
+
+func appendString(out []byte, in string) ([]byte, error) {
+	out = append(out, '"')
+	i := indexNeedEscapeInString(in)
+	in, out = in[i:], append(out, in[:i]...)
+	for len(in) > 0 {
+		switch r, n := utf8.DecodeRuneInString(in); {
+		case r == utf8.RuneError && n == 1:
+			return out, errInvalidUTF8
+		case r < ' ' || r == '"' || r == '\\':
+			out = append(out, '\\')
+			switch r {
+			case '"', '\\':
+				out = append(out, byte(r))
+			case '\b':
+				out = append(out, 'b')
+			case '\f':
+				out = append(out, 'f')
+			case '\n':
+				out = append(out, 'n')
+			case '\r':
+				out = append(out, 'r')
+			case '\t':
+				out = append(out, 't')
+			default:
+				out = append(out, 'u')
+				out = append(out, "0000"[1+(bits.Len32(uint32(r))-1)/4:]...)
+				out = strconv.AppendUint(out, uint64(r), 16)
+			}
+			in = in[n:]
+		default:
+			i := indexNeedEscapeInString(in[n:])
+			in, out = in[n+i:], append(out, in[:n+i]...)
+		}
+	}
+	out = append(out, '"')
+	return out, nil
+}
+
+// indexNeedEscapeInString returns the index of the character that needs
+// escaping. If no characters need escaping, this returns the input length.
+func indexNeedEscapeInString(s string) int {
+	for i, r := range s {
+		if r < ' ' || r == '\\' || r == '"' || r == utf8.RuneError {
+			return i
+		}
+	}
+	return len(s)
+}
+
+// WriteFloat writes out the given float and bitSize in JSON number value.
+func (e *Encoder) WriteFloat(n float64, bitSize int) {
+	e.prepareNext(scalar)
+	e.out = appendFloat(e.out, n, bitSize)
+}
+
+// appendFloat formats given float in bitSize, and appends to the given []byte.
+func appendFloat(out []byte, n float64, bitSize int) []byte {
+	switch {
+	case math.IsNaN(n):
+		return append(out, `"NaN"`...)
+	case math.IsInf(n, +1):
+		return append(out, `"Infinity"`...)
+	case math.IsInf(n, -1):
+		return append(out, `"-Infinity"`...)
+	}
+
+	// JSON number formatting logic based on encoding/json.
+	// See floatEncoder.encode for reference.
+	fmt := byte('f')
+	if abs := math.Abs(n); abs != 0 {
+		if bitSize == 64 && (abs < 1e-6 || abs >= 1e21) ||
+			bitSize == 32 && (float32(abs) < 1e-6 || float32(abs) >= 1e21) {
+			fmt = 'e'
+		}
+	}
+	out = strconv.AppendFloat(out, n, fmt, -1, bitSize)
+	if fmt == 'e' {
+		n := len(out)
+		if n >= 4 && out[n-4] == 'e' && out[n-3] == '-' && out[n-2] == '0' {
+			out[n-2] = out[n-1]
+			out = out[:n-1]
+		}
+	}
+	return out
+}
+
+// WriteInt writes out the given signed integer in JSON number value.
+func (e *Encoder) WriteInt(n int64) {
+	e.prepareNext(scalar)
+	e.out = append(e.out, strconv.FormatInt(n, 10)...)
+}
+
+// WriteUint writes out the given unsigned integer in JSON number value.
+func (e *Encoder) WriteUint(n uint64) {
+	e.prepareNext(scalar)
+	e.out = append(e.out, strconv.FormatUint(n, 10)...)
+}
+
+// StartObject writes out the '{' symbol.
+func (e *Encoder) StartObject() {
+	e.prepareNext(objectOpen)
+	e.out = append(e.out, '{')
+}
+
+// EndObject writes out the '}' symbol.
+func (e *Encoder) EndObject() {
+	e.prepareNext(objectClose)
+	e.out = append(e.out, '}')
+}
+
+// WriteName writes out the given string in JSON string value and the name
+// separator ':'. Returns error if input string contains invalid UTF-8, which
+// should not be likely as protobuf field names should be valid.
+func (e *Encoder) WriteName(s string) error {
+	e.prepareNext(name)
+	var err error
+	// Append to output regardless of error.
+	e.out, err = appendString(e.out, s)
+	e.out = append(e.out, ':')
+	return err
+}
+
+// StartArray writes out the '[' symbol.
+func (e *Encoder) StartArray() {
+	e.prepareNext(arrayOpen)
+	e.out = append(e.out, '[')
+}
+
+// EndArray writes out the ']' symbol.
+func (e *Encoder) EndArray() {
+	e.prepareNext(arrayClose)
+	e.out = append(e.out, ']')
+}
+
+// prepareNext adds possible comma and indentation for the next value based
+// on last type and indent option. It also updates lastKind to next.
+func (e *Encoder) prepareNext(next kind) {
+	defer func() {
+		// Set lastKind to next.
+		e.lastKind = next
+	}()
+
+	if len(e.indent) == 0 {
+		// Need to add comma on the following condition.
+		if e.lastKind&(scalar|objectClose|arrayClose) != 0 &&
+			next&(name|scalar|objectOpen|arrayOpen) != 0 {
+			e.out = append(e.out, ',')
+			// For single-line output, add a random extra space after each
+			// comma to make output unstable.
+			if detrand.Bool() {
+				e.out = append(e.out, ' ')
+			}
+		}
+		return
+	}
+
+	switch {
+	case e.lastKind&(objectOpen|arrayOpen) != 0:
+		// If next type is NOT closing, add indent and newline.
+		if next&(objectClose|arrayClose) == 0 {
+			e.indents = append(e.indents, e.indent...)
+			e.out = append(e.out, '\n')
+			e.out = append(e.out, e.indents...)
+		}
+
+	case e.lastKind&(scalar|objectClose|arrayClose) != 0:
+		switch {
+		// If next type is either a value or name, add comma and newline.
+		case next&(name|scalar|objectOpen|arrayOpen) != 0:
+			e.out = append(e.out, ',', '\n')
+
+		// If next type is a closing object or array, adjust indentation.
+		case next&(objectClose|arrayClose) != 0:
+			e.indents = e.indents[:len(e.indents)-len(e.indent)]
+			e.out = append(e.out, '\n')
+		}
+		e.out = append(e.out, e.indents...)
+
+	case e.lastKind&name != 0:
+		e.out = append(e.out, ' ')
+		// For multi-line output, add a random extra space after key: to make
+		// output unstable.
+		if detrand.Bool() {
+			e.out = append(e.out, ' ')
+		}
+	}
+}