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mumbledj/vendor/github.com/golang/protobuf/jsonpb/jsonpb.go
2016-06-20 17:50:40 -07:00

800 lines
22 KiB
Go

// Go support for Protocol Buffers - Google's data interchange format
//
// Copyright 2015 The Go Authors. All rights reserved.
// https://github.com/golang/protobuf
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
/*
Package jsonpb provides marshaling and unmarshaling between protocol buffers and JSON.
It follows the specification at https://developers.google.com/protocol-buffers/docs/proto3#json.
This package produces a different output than the standard "encoding/json" package,
which does not operate correctly on protocol buffers.
*/
package jsonpb
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"reflect"
"sort"
"strconv"
"strings"
"time"
"github.com/golang/protobuf/proto"
)
// Marshaler is a configurable object for converting between
// protocol buffer objects and a JSON representation for them.
type Marshaler struct {
// Whether to render enum values as integers, as opposed to string values.
EnumsAsInts bool
// Whether to render fields with zero values.
EmitDefaults bool
// A string to indent each level by. The presence of this field will
// also cause a space to appear between the field separator and
// value, and for newlines to be appear between fields and array
// elements.
Indent string
// Whether to use the original (.proto) name for fields.
OrigName bool
}
// Marshal marshals a protocol buffer into JSON.
func (m *Marshaler) Marshal(out io.Writer, pb proto.Message) error {
writer := &errWriter{writer: out}
return m.marshalObject(writer, pb, "", "")
}
// MarshalToString converts a protocol buffer object to JSON string.
func (m *Marshaler) MarshalToString(pb proto.Message) (string, error) {
var buf bytes.Buffer
if err := m.Marshal(&buf, pb); err != nil {
return "", err
}
return buf.String(), nil
}
type int32Slice []int32
// For sorting extensions ids to ensure stable output.
func (s int32Slice) Len() int { return len(s) }
func (s int32Slice) Less(i, j int) bool { return s[i] < s[j] }
func (s int32Slice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
type wkt interface {
XXX_WellKnownType() string
}
// marshalObject writes a struct to the Writer.
func (m *Marshaler) marshalObject(out *errWriter, v proto.Message, indent, typeURL string) error {
s := reflect.ValueOf(v).Elem()
// Handle well-known types.
if wkt, ok := v.(wkt); ok {
switch wkt.XXX_WellKnownType() {
case "DoubleValue", "FloatValue", "Int64Value", "UInt64Value",
"Int32Value", "UInt32Value", "BoolValue", "StringValue", "BytesValue":
// "Wrappers use the same representation in JSON
// as the wrapped primitive type, ..."
sprop := proto.GetProperties(s.Type())
return m.marshalValue(out, sprop.Prop[0], s.Field(0), indent)
case "Any":
// Any is a bit more involved.
return m.marshalAny(out, v, indent)
case "Duration":
// "Generated output always contains 3, 6, or 9 fractional digits,
// depending on required precision."
s, ns := s.Field(0).Int(), s.Field(1).Int()
d := time.Duration(s)*time.Second + time.Duration(ns)*time.Nanosecond
x := fmt.Sprintf("%.9f", d.Seconds())
x = strings.TrimSuffix(x, "000")
x = strings.TrimSuffix(x, "000")
out.write(`"`)
out.write(x)
out.write(`s"`)
return out.err
case "Struct":
// Let marshalValue handle the `fields` map.
// TODO: pass the correct Properties if needed.
return m.marshalValue(out, &proto.Properties{}, s.Field(0), indent)
case "Timestamp":
// "RFC 3339, where generated output will always be Z-normalized
// and uses 3, 6 or 9 fractional digits."
s, ns := s.Field(0).Int(), s.Field(1).Int()
t := time.Unix(s, ns).UTC()
// time.RFC3339Nano isn't exactly right (we need to get 3/6/9 fractional digits).
x := t.Format("2006-01-02T15:04:05.000000000")
x = strings.TrimSuffix(x, "000")
x = strings.TrimSuffix(x, "000")
out.write(`"`)
out.write(x)
out.write(`Z"`)
return out.err
case "Value":
// Value has a single oneof.
kind := s.Field(0)
if kind.IsNil() {
// "absence of any variant indicates an error"
return errors.New("nil Value")
}
// oneof -> *T -> T -> T.F
x := kind.Elem().Elem().Field(0)
// TODO: pass the correct Properties if needed.
return m.marshalValue(out, &proto.Properties{}, x, indent)
}
}
out.write("{")
if m.Indent != "" {
out.write("\n")
}
firstField := true
if typeURL != "" {
if err := m.marshalTypeURL(out, indent, typeURL); err != nil {
return err
}
firstField = false
}
for i := 0; i < s.NumField(); i++ {
value := s.Field(i)
valueField := s.Type().Field(i)
if strings.HasPrefix(valueField.Name, "XXX_") {
continue
}
// IsNil will panic on most value kinds.
switch value.Kind() {
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
if value.IsNil() {
continue
}
}
if !m.EmitDefaults {
switch value.Kind() {
case reflect.Bool:
if !value.Bool() {
continue
}
case reflect.Int32, reflect.Int64:
if value.Int() == 0 {
continue
}
case reflect.Uint32, reflect.Uint64:
if value.Uint() == 0 {
continue
}
case reflect.Float32, reflect.Float64:
if value.Float() == 0 {
continue
}
case reflect.String:
if value.Len() == 0 {
continue
}
}
}
// Oneof fields need special handling.
if valueField.Tag.Get("protobuf_oneof") != "" {
// value is an interface containing &T{real_value}.
sv := value.Elem().Elem() // interface -> *T -> T
value = sv.Field(0)
valueField = sv.Type().Field(0)
}
prop := jsonProperties(valueField, m.OrigName)
if !firstField {
m.writeSep(out)
}
if err := m.marshalField(out, prop, value, indent); err != nil {
return err
}
firstField = false
}
// Handle proto2 extensions.
if ep, ok := v.(proto.Message); ok {
extensions := proto.RegisteredExtensions(v)
// Sort extensions for stable output.
ids := make([]int32, 0, len(extensions))
for id, desc := range extensions {
if !proto.HasExtension(ep, desc) {
continue
}
ids = append(ids, id)
}
sort.Sort(int32Slice(ids))
for _, id := range ids {
desc := extensions[id]
if desc == nil {
// unknown extension
continue
}
ext, extErr := proto.GetExtension(ep, desc)
if extErr != nil {
return extErr
}
value := reflect.ValueOf(ext)
var prop proto.Properties
prop.Parse(desc.Tag)
prop.JSONName = fmt.Sprintf("[%s]", desc.Name)
if !firstField {
m.writeSep(out)
}
if err := m.marshalField(out, &prop, value, indent); err != nil {
return err
}
firstField = false
}
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
}
out.write("}")
return out.err
}
func (m *Marshaler) writeSep(out *errWriter) {
if m.Indent != "" {
out.write(",\n")
} else {
out.write(",")
}
}
func (m *Marshaler) marshalAny(out *errWriter, any proto.Message, indent string) error {
// "If the Any contains a value that has a special JSON mapping,
// it will be converted as follows: {"@type": xxx, "value": yyy}.
// Otherwise, the value will be converted into a JSON object,
// and the "@type" field will be inserted to indicate the actual data type."
v := reflect.ValueOf(any).Elem()
turl := v.Field(0).String()
val := v.Field(1).Bytes()
// Only the part of type_url after the last slash is relevant.
mname := turl
if slash := strings.LastIndex(mname, "/"); slash >= 0 {
mname = mname[slash+1:]
}
mt := proto.MessageType(mname)
if mt == nil {
return fmt.Errorf("unknown message type %q", mname)
}
msg := reflect.New(mt.Elem()).Interface().(proto.Message)
if err := proto.Unmarshal(val, msg); err != nil {
return err
}
if _, ok := msg.(wkt); ok {
out.write("{")
if m.Indent != "" {
out.write("\n")
}
if err := m.marshalTypeURL(out, indent, turl); err != nil {
return err
}
m.writeSep(out)
if m.Indent != "" {
out.write(indent)
out.write(m.Indent)
out.write(`"value": `)
} else {
out.write(`"value":`)
}
if err := m.marshalObject(out, msg, indent+m.Indent, ""); err != nil {
return err
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
}
out.write("}")
return out.err
}
return m.marshalObject(out, msg, indent, turl)
}
func (m *Marshaler) marshalTypeURL(out *errWriter, indent, typeURL string) error {
if m.Indent != "" {
out.write(indent)
out.write(m.Indent)
}
out.write(`"@type":`)
if m.Indent != "" {
out.write(" ")
}
b, err := json.Marshal(typeURL)
if err != nil {
return err
}
out.write(string(b))
return out.err
}
// marshalField writes field description and value to the Writer.
func (m *Marshaler) marshalField(out *errWriter, prop *proto.Properties, v reflect.Value, indent string) error {
if m.Indent != "" {
out.write(indent)
out.write(m.Indent)
}
out.write(`"`)
out.write(prop.JSONName)
out.write(`":`)
if m.Indent != "" {
out.write(" ")
}
if err := m.marshalValue(out, prop, v, indent); err != nil {
return err
}
return nil
}
// marshalValue writes the value to the Writer.
func (m *Marshaler) marshalValue(out *errWriter, prop *proto.Properties, v reflect.Value, indent string) error {
var err error
v = reflect.Indirect(v)
// Handle repeated elements.
if v.Kind() == reflect.Slice && v.Type().Elem().Kind() != reflect.Uint8 {
out.write("[")
comma := ""
for i := 0; i < v.Len(); i++ {
sliceVal := v.Index(i)
out.write(comma)
if m.Indent != "" {
out.write("\n")
out.write(indent)
out.write(m.Indent)
out.write(m.Indent)
}
if err := m.marshalValue(out, prop, sliceVal, indent+m.Indent); err != nil {
return err
}
comma = ","
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
out.write(m.Indent)
}
out.write("]")
return out.err
}
// Handle well-known types.
// Most are handled up in marshalObject (because 99% are messages).
type wkt interface {
XXX_WellKnownType() string
}
if wkt, ok := v.Interface().(wkt); ok {
switch wkt.XXX_WellKnownType() {
case "NullValue":
out.write("null")
return out.err
}
}
// Handle enumerations.
if !m.EnumsAsInts && prop.Enum != "" {
// Unknown enum values will are stringified by the proto library as their
// value. Such values should _not_ be quoted or they will be interpreted
// as an enum string instead of their value.
enumStr := v.Interface().(fmt.Stringer).String()
var valStr string
if v.Kind() == reflect.Ptr {
valStr = strconv.Itoa(int(v.Elem().Int()))
} else {
valStr = strconv.Itoa(int(v.Int()))
}
isKnownEnum := enumStr != valStr
if isKnownEnum {
out.write(`"`)
}
out.write(enumStr)
if isKnownEnum {
out.write(`"`)
}
return out.err
}
// Handle nested messages.
if v.Kind() == reflect.Struct {
return m.marshalObject(out, v.Addr().Interface().(proto.Message), indent+m.Indent, "")
}
// Handle maps.
// Since Go randomizes map iteration, we sort keys for stable output.
if v.Kind() == reflect.Map {
out.write(`{`)
keys := v.MapKeys()
sort.Sort(mapKeys(keys))
for i, k := range keys {
if i > 0 {
out.write(`,`)
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
out.write(m.Indent)
out.write(m.Indent)
}
b, err := json.Marshal(k.Interface())
if err != nil {
return err
}
s := string(b)
// If the JSON is not a string value, encode it again to make it one.
if !strings.HasPrefix(s, `"`) {
b, err := json.Marshal(s)
if err != nil {
return err
}
s = string(b)
}
out.write(s)
out.write(`:`)
if m.Indent != "" {
out.write(` `)
}
if err := m.marshalValue(out, prop, v.MapIndex(k), indent+m.Indent); err != nil {
return err
}
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
out.write(m.Indent)
}
out.write(`}`)
return out.err
}
// Default handling defers to the encoding/json library.
b, err := json.Marshal(v.Interface())
if err != nil {
return err
}
needToQuote := string(b[0]) != `"` && (v.Kind() == reflect.Int64 || v.Kind() == reflect.Uint64)
if needToQuote {
out.write(`"`)
}
out.write(string(b))
if needToQuote {
out.write(`"`)
}
return out.err
}
// UnmarshalNext unmarshals the next protocol buffer from a JSON object stream.
// This function is lenient and will decode any options permutations of the
// related Marshaler.
func UnmarshalNext(dec *json.Decoder, pb proto.Message) error {
inputValue := json.RawMessage{}
if err := dec.Decode(&inputValue); err != nil {
return err
}
return unmarshalValue(reflect.ValueOf(pb).Elem(), inputValue, nil)
}
// Unmarshal unmarshals a JSON object stream into a protocol
// buffer. This function is lenient and will decode any options
// permutations of the related Marshaler.
func Unmarshal(r io.Reader, pb proto.Message) error {
dec := json.NewDecoder(r)
return UnmarshalNext(dec, pb)
}
// UnmarshalString will populate the fields of a protocol buffer based
// on a JSON string. This function is lenient and will decode any options
// permutations of the related Marshaler.
func UnmarshalString(str string, pb proto.Message) error {
return Unmarshal(strings.NewReader(str), pb)
}
// unmarshalValue converts/copies a value into the target.
// prop may be nil.
func unmarshalValue(target reflect.Value, inputValue json.RawMessage, prop *proto.Properties) error {
targetType := target.Type()
// Allocate memory for pointer fields.
if targetType.Kind() == reflect.Ptr {
target.Set(reflect.New(targetType.Elem()))
return unmarshalValue(target.Elem(), inputValue, prop)
}
// Handle well-known types.
type wkt interface {
XXX_WellKnownType() string
}
if wkt, ok := target.Addr().Interface().(wkt); ok {
switch wkt.XXX_WellKnownType() {
case "DoubleValue", "FloatValue", "Int64Value", "UInt64Value",
"Int32Value", "UInt32Value", "BoolValue", "StringValue", "BytesValue":
// "Wrappers use the same representation in JSON
// as the wrapped primitive type, except that null is allowed."
// encoding/json will turn JSON `null` into Go `nil`,
// so we don't have to do any extra work.
return unmarshalValue(target.Field(0), inputValue, prop)
case "Any":
return fmt.Errorf("unmarshaling Any not supported yet")
case "Duration":
unq, err := strconv.Unquote(string(inputValue))
if err != nil {
return err
}
d, err := time.ParseDuration(unq)
if err != nil {
return fmt.Errorf("bad Duration: %v", err)
}
ns := d.Nanoseconds()
s := ns / 1e9
ns %= 1e9
target.Field(0).SetInt(s)
target.Field(1).SetInt(ns)
return nil
case "Timestamp":
unq, err := strconv.Unquote(string(inputValue))
if err != nil {
return err
}
t, err := time.Parse(time.RFC3339Nano, unq)
if err != nil {
return fmt.Errorf("bad Timestamp: %v", err)
}
ns := t.UnixNano()
s := ns / 1e9
ns %= 1e9
target.Field(0).SetInt(s)
target.Field(1).SetInt(ns)
return nil
}
}
// Handle enums, which have an underlying type of int32,
// and may appear as strings.
// The case of an enum appearing as a number is handled
// at the bottom of this function.
if inputValue[0] == '"' && prop != nil && prop.Enum != "" {
vmap := proto.EnumValueMap(prop.Enum)
// Don't need to do unquoting; valid enum names
// are from a limited character set.
s := inputValue[1 : len(inputValue)-1]
n, ok := vmap[string(s)]
if !ok {
return fmt.Errorf("unknown value %q for enum %s", s, prop.Enum)
}
if target.Kind() == reflect.Ptr { // proto2
target.Set(reflect.New(targetType.Elem()))
target = target.Elem()
}
target.SetInt(int64(n))
return nil
}
// Handle nested messages.
if targetType.Kind() == reflect.Struct {
var jsonFields map[string]json.RawMessage
if err := json.Unmarshal(inputValue, &jsonFields); err != nil {
return err
}
consumeField := func(prop *proto.Properties) (json.RawMessage, bool) {
// Be liberal in what names we accept; both orig_name and camelName are okay.
fieldNames := acceptedJSONFieldNames(prop)
vOrig, okOrig := jsonFields[fieldNames.orig]
vCamel, okCamel := jsonFields[fieldNames.camel]
if !okOrig && !okCamel {
return nil, false
}
// If, for some reason, both are present in the data, favour the camelName.
var raw json.RawMessage
if okOrig {
raw = vOrig
delete(jsonFields, fieldNames.orig)
}
if okCamel {
raw = vCamel
delete(jsonFields, fieldNames.camel)
}
return raw, true
}
sprops := proto.GetProperties(targetType)
for i := 0; i < target.NumField(); i++ {
ft := target.Type().Field(i)
if strings.HasPrefix(ft.Name, "XXX_") {
continue
}
valueForField, ok := consumeField(sprops.Prop[i])
if !ok {
continue
}
if err := unmarshalValue(target.Field(i), valueForField, sprops.Prop[i]); err != nil {
return err
}
}
// Check for any oneof fields.
if len(jsonFields) > 0 {
for _, oop := range sprops.OneofTypes {
raw, ok := consumeField(oop.Prop)
if !ok {
continue
}
nv := reflect.New(oop.Type.Elem())
target.Field(oop.Field).Set(nv)
if err := unmarshalValue(nv.Elem().Field(0), raw, oop.Prop); err != nil {
return err
}
}
}
if len(jsonFields) > 0 {
// Pick any field to be the scapegoat.
var f string
for fname := range jsonFields {
f = fname
break
}
return fmt.Errorf("unknown field %q in %v", f, targetType)
}
return nil
}
// Handle arrays (which aren't encoded bytes)
if targetType.Kind() == reflect.Slice && targetType.Elem().Kind() != reflect.Uint8 {
var slc []json.RawMessage
if err := json.Unmarshal(inputValue, &slc); err != nil {
return err
}
len := len(slc)
target.Set(reflect.MakeSlice(targetType, len, len))
for i := 0; i < len; i++ {
if err := unmarshalValue(target.Index(i), slc[i], prop); err != nil {
return err
}
}
return nil
}
// Handle maps (whose keys are always strings)
if targetType.Kind() == reflect.Map {
var mp map[string]json.RawMessage
if err := json.Unmarshal(inputValue, &mp); err != nil {
return err
}
target.Set(reflect.MakeMap(targetType))
var keyprop, valprop *proto.Properties
if prop != nil {
// These could still be nil if the protobuf metadata is broken somehow.
// TODO: This won't work because the fields are unexported.
// We should probably just reparse them.
//keyprop, valprop = prop.mkeyprop, prop.mvalprop
}
for ks, raw := range mp {
// Unmarshal map key. The core json library already decoded the key into a
// string, so we handle that specially. Other types were quoted post-serialization.
var k reflect.Value
if targetType.Key().Kind() == reflect.String {
k = reflect.ValueOf(ks)
} else {
k = reflect.New(targetType.Key()).Elem()
if err := unmarshalValue(k, json.RawMessage(ks), keyprop); err != nil {
return err
}
}
// Unmarshal map value.
v := reflect.New(targetType.Elem()).Elem()
if err := unmarshalValue(v, raw, valprop); err != nil {
return err
}
target.SetMapIndex(k, v)
}
return nil
}
// 64-bit integers can be encoded as strings. In this case we drop
// the quotes and proceed as normal.
isNum := targetType.Kind() == reflect.Int64 || targetType.Kind() == reflect.Uint64
if isNum && strings.HasPrefix(string(inputValue), `"`) {
inputValue = inputValue[1 : len(inputValue)-1]
}
// Use the encoding/json for parsing other value types.
return json.Unmarshal(inputValue, target.Addr().Interface())
}
// jsonProperties returns parsed proto.Properties for the field and corrects JSONName attribute.
func jsonProperties(f reflect.StructField, origName bool) *proto.Properties {
var prop proto.Properties
prop.Init(f.Type, f.Name, f.Tag.Get("protobuf"), &f)
if origName || prop.JSONName == "" {
prop.JSONName = prop.OrigName
}
return &prop
}
type fieldNames struct {
orig, camel string
}
func acceptedJSONFieldNames(prop *proto.Properties) fieldNames {
opts := fieldNames{orig: prop.OrigName, camel: prop.OrigName}
if prop.JSONName != "" {
opts.camel = prop.JSONName
}
return opts
}
// Writer wrapper inspired by https://blog.golang.org/errors-are-values
type errWriter struct {
writer io.Writer
err error
}
func (w *errWriter) write(str string) {
if w.err != nil {
return
}
_, w.err = w.writer.Write([]byte(str))
}
// Map fields may have key types of non-float scalars, strings and enums.
// The easiest way to sort them in some deterministic order is to use fmt.
// If this turns out to be inefficient we can always consider other options,
// such as doing a Schwartzian transform.
type mapKeys []reflect.Value
func (s mapKeys) Len() int { return len(s) }
func (s mapKeys) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s mapKeys) Less(i, j int) bool {
return fmt.Sprint(s[i].Interface()) < fmt.Sprint(s[j].Interface())
}