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// 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 jsonpb
import (
"encoding/base64"
"fmt"
"sort"
"google.golang.org/protobuf/internal/encoding/json"
"google.golang.org/protobuf/internal/errors"
"google.golang.org/protobuf/internal/pragma"
"google.golang.org/protobuf/proto"
pref "google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/reflect/protoregistry"
)
// Marshal writes the given proto.Message in JSON format using default options.
func Marshal(m proto.Message) ([]byte, error) {
return MarshalOptions{}.Marshal(m)
}
// MarshalOptions is a configurable JSON format marshaler.
type MarshalOptions struct {
pragma.NoUnkeyedLiterals
// AllowPartial allows messages that have missing required fields to marshal
// without returning an error. If AllowPartial is false (the default),
// Marshal will return error if there are any missing required fields.
AllowPartial bool
// If Indent is a non-empty string, it causes entries for an Array or Object
// to be preceded by the indent and trailed by a newline. Indent can only be
// composed of space or tab characters.
Indent string
// Resolver is the registry used for type lookups when marshaling
// google.protobuf.Any messages. If Resolver is not set, marshaling will
// default to using protoregistry.GlobalTypes.
Resolver *protoregistry.Types
encoder *json.Encoder
}
// Marshal marshals the given proto.Message in the JSON format using options in
// MarshalOptions.
func (o MarshalOptions) Marshal(m proto.Message) ([]byte, error) {
var err error
o.encoder, err = json.NewEncoder(o.Indent)
if err != nil {
return nil, err
}
if o.Resolver == nil {
o.Resolver = protoregistry.GlobalTypes
}
var nerr errors.NonFatal
err = o.marshalMessage(m.ProtoReflect())
if !nerr.Merge(err) {
return nil, err
}
if !o.AllowPartial {
nerr.Merge(proto.IsInitialized(m))
}
return o.encoder.Bytes(), nerr.E
}
// marshalMessage marshals the given protoreflect.Message.
func (o MarshalOptions) marshalMessage(m pref.Message) error {
var nerr errors.NonFatal
if isCustomType(m.Descriptor().FullName()) {
return o.marshalCustomType(m)
}
o.encoder.StartObject()
defer o.encoder.EndObject()
if err := o.marshalFields(m); !nerr.Merge(err) {
return err
}
return nerr.E
}
// marshalFields marshals the fields in the given protoreflect.Message.
func (o MarshalOptions) marshalFields(m pref.Message) error {
var nerr errors.NonFatal
fieldDescs := m.Descriptor().Fields()
knownFields := m.KnownFields()
// Marshal out known fields.
for i := 0; i < fieldDescs.Len(); i++ {
fd := fieldDescs.Get(i)
num := fd.Number()
if !knownFields.Has(num) {
continue
}
name := fd.JSONName()
val := knownFields.Get(num)
if err := o.encoder.WriteName(name); !nerr.Merge(err) {
return err
}
if err := o.marshalValue(val, fd); !nerr.Merge(err) {
return err
}
}
// Marshal out extensions.
if err := o.marshalExtensions(knownFields); !nerr.Merge(err) {
return err
}
return nerr.E
}
// marshalValue marshals the given protoreflect.Value.
func (o MarshalOptions) marshalValue(val pref.Value, fd pref.FieldDescriptor) error {
switch {
case fd.IsList():
return o.marshalList(val.List(), fd)
case fd.IsMap():
return o.marshalMap(val.Map(), fd)
default:
return o.marshalSingular(val, fd)
}
}
// marshalSingular marshals the given non-repeated field value. This includes
// all scalar types, enums, messages, and groups.
func (o MarshalOptions) marshalSingular(val pref.Value, fd pref.FieldDescriptor) error {
var nerr errors.NonFatal
switch kind := fd.Kind(); kind {
case pref.BoolKind:
o.encoder.WriteBool(val.Bool())
case pref.StringKind:
if err := o.encoder.WriteString(val.String()); !nerr.Merge(err) {
return err
}
case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind:
o.encoder.WriteInt(val.Int())
case pref.Uint32Kind, pref.Fixed32Kind:
o.encoder.WriteUint(val.Uint())
case pref.Int64Kind, pref.Sint64Kind, pref.Uint64Kind,
pref.Sfixed64Kind, pref.Fixed64Kind:
// 64-bit integers are written out as JSON string.
o.encoder.WriteString(val.String())
case pref.FloatKind:
// Encoder.WriteFloat handles the special numbers NaN and infinites.
o.encoder.WriteFloat(val.Float(), 32)
case pref.DoubleKind:
// Encoder.WriteFloat handles the special numbers NaN and infinites.
o.encoder.WriteFloat(val.Float(), 64)
case pref.BytesKind:
err := o.encoder.WriteString(base64.StdEncoding.EncodeToString(val.Bytes()))
if !nerr.Merge(err) {
return err
}
case pref.EnumKind:
if fd.Enum().FullName() == "google.protobuf.NullValue" {
o.encoder.WriteNull()
} else if desc := fd.Enum().Values().ByNumber(val.Enum()); desc != nil {
err := o.encoder.WriteString(string(desc.Name()))
if !nerr.Merge(err) {
return err
}
} else {
// Use numeric value if there is no enum value descriptor.
o.encoder.WriteInt(int64(val.Enum()))
}
case pref.MessageKind, pref.GroupKind:
if err := o.marshalMessage(val.Message()); !nerr.Merge(err) {
return err
}
default:
panic(fmt.Sprintf("%v has unknown kind: %v", fd.FullName(), kind))
}
return nerr.E
}
// marshalList marshals the given protoreflect.List.
func (o MarshalOptions) marshalList(list pref.List, fd pref.FieldDescriptor) error {
o.encoder.StartArray()
defer o.encoder.EndArray()
var nerr errors.NonFatal
for i := 0; i < list.Len(); i++ {
item := list.Get(i)
if err := o.marshalSingular(item, fd); !nerr.Merge(err) {
return err
}
}
return nerr.E
}
type mapEntry struct {
key pref.MapKey
value pref.Value
}
// marshalMap marshals given protoreflect.Map.
func (o MarshalOptions) marshalMap(mmap pref.Map, fd pref.FieldDescriptor) error {
o.encoder.StartObject()
defer o.encoder.EndObject()
// Get a sorted list based on keyType first.
entries := make([]mapEntry, 0, mmap.Len())
mmap.Range(func(key pref.MapKey, val pref.Value) bool {
entries = append(entries, mapEntry{key: key, value: val})
return true
})
sortMap(fd.MapKey().Kind(), entries)
// Write out sorted list.
var nerr errors.NonFatal
for _, entry := range entries {
if err := o.encoder.WriteName(entry.key.String()); !nerr.Merge(err) {
return err
}
if err := o.marshalSingular(entry.value, fd.MapValue()); !nerr.Merge(err) {
return err
}
}
return nerr.E
}
// sortMap orders list based on value of key field for deterministic ordering.
func sortMap(keyKind pref.Kind, values []mapEntry) {
sort.Slice(values, func(i, j int) bool {
switch keyKind {
case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind,
pref.Int64Kind, pref.Sint64Kind, pref.Sfixed64Kind:
return values[i].key.Int() < values[j].key.Int()
case pref.Uint32Kind, pref.Fixed32Kind,
pref.Uint64Kind, pref.Fixed64Kind:
return values[i].key.Uint() < values[j].key.Uint()
}
return values[i].key.String() < values[j].key.String()
})
}
// marshalExtensions marshals extension fields.
func (o MarshalOptions) marshalExtensions(knownFields pref.KnownFields) error {
type xtEntry struct {
key string
value pref.Value
xtType pref.ExtensionType
}
xtTypes := knownFields.ExtensionTypes()
// Get a sorted list based on field key first.
entries := make([]xtEntry, 0, xtTypes.Len())
xtTypes.Range(func(xt pref.ExtensionType) bool {
name := xt.Descriptor().FullName()
// If extended type is a MessageSet, set field name to be the message type name.
if isMessageSetExtension(xt) {
name = xt.Descriptor().Message().FullName()
}
num := xt.Descriptor().Number()
if knownFields.Has(num) {
// Use [name] format for JSON field name.
pval := knownFields.Get(num)
entries = append(entries, xtEntry{
key: string(name),
value: pval,
xtType: xt,
})
}
return true
})
// Sort extensions lexicographically.
sort.Slice(entries, func(i, j int) bool {
return entries[i].key < entries[j].key
})
// Write out sorted list.
var nerr errors.NonFatal
for _, entry := range entries {
// JSON field name is the proto field name enclosed in [], similar to
// textproto. This is consistent with Go v1 lib. C++ lib v3.7.0 does not
// marshal out extension fields.
if err := o.encoder.WriteName("[" + entry.key + "]"); !nerr.Merge(err) {
return err
}
if err := o.marshalValue(entry.value, entry.xtType.Descriptor()); !nerr.Merge(err) {
return err
}
}
return nerr.E
}
// isMessageSetExtension reports whether extension extends a message set.
func isMessageSetExtension(xt pref.ExtensionType) bool {
xd := xt.Descriptor()
if xd.Name() != "message_set_extension" {
return false
}
md := xd.Message()
if md == nil {
return false
}
if xd.FullName().Parent() != md.FullName() {
return false
}
xmd, ok := xd.ContainingMessage().(interface{ IsMessageSet() bool })
return ok && xmd.IsMessageSet()
}