/
binary.go
196 lines (182 loc) · 4.44 KB
/
binary.go
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package utils
// Adjusted from https://github.com/jhump/protoreflect/blob/d24a736ca94c38e8d70a2de6be6254aa99a5966b/dynamic/binary.go
import (
"fmt"
"io"
"github.com/golang/protobuf/proto"
"github.com/golang/protobuf/protoc-gen-go/descriptor"
"github.com/jhump/protoreflect/desc"
)
type decoder struct {
msgDesc *desc.MessageDescriptor
visitor func(pos int, len int, msgDesc *desc.MessageDescriptor)
}
func (d *decoder) Unmarshal(b []byte) error {
return d.unmarshal(newCodedBuffer(b), false)
}
func (d *decoder) unmarshal(buf *codedBuffer, isGroup bool) error {
for !buf.eof() {
tagNumber, wireType, err := buf.decodeTagAndWireType()
if err != nil {
return err
}
if wireType == proto.WireEndGroup {
if isGroup {
// finished parsing group
return nil
}
return proto.ErrInternalBadWireType
}
fd := d.msgDesc.FindFieldByNumber(tagNumber)
if fd == nil {
err := unmarshalUnknownField(wireType, buf)
if err != nil {
return err
}
} else {
err := d.unmarshalKnownField(fd, wireType, buf)
if err != nil {
return err
}
}
}
if isGroup {
return io.ErrUnexpectedEOF
}
return nil
}
func (d *decoder) unmarshalKnownField(fd *desc.FieldDescriptor, encoding int8, b *codedBuffer) error {
var err error
switch encoding {
case proto.WireFixed32:
_, err = b.decodeFixed32()
case proto.WireFixed64:
_, err = b.decodeFixed64()
case proto.WireVarint:
_, err = b.decodeVarint()
case proto.WireBytes:
start := b.index
_, err = b.decodeVarint()
if err == nil {
startData := b.index
b.index = start
var raw []byte
raw, err = b.decodeRawBytes(false)
if err == nil && (fd.GetType() == descriptor.FieldDescriptorProto_TYPE_MESSAGE || fd.GetType() == descriptor.FieldDescriptorProto_TYPE_GROUP) {
if fd.GetMessageType() == nil {
return fmt.Errorf("cannot parse field %s from byte-encoded wire type", fd.GetFullyQualifiedName())
}
visitor := func(pos int, len int, msgDesc *desc.MessageDescriptor) {
d.visitor(startData+pos, len, msgDesc)
}
newDecoder := &decoder{msgDesc: fd.GetMessageType(), visitor: visitor}
err = newDecoder.Unmarshal(raw)
if err == nil {
d.visitor(startData, len(raw), fd.GetMessageType())
}
}
}
case proto.WireStartGroup:
if fd.GetMessageType() == nil {
return fmt.Errorf("cannot parse field %s from group-encoded wire type", fd.GetFullyQualifiedName())
}
newDecoder := &decoder{msgDesc: fd.GetMessageType(), visitor: d.visitor}
before := b.index
err = newDecoder.unmarshal(b, true)
if err == nil {
d.visitor(before, b.index-before, fd.GetMessageType())
}
default:
return proto.ErrInternalBadWireType
}
if err != nil {
return err
}
return nil
}
func unmarshalUnknownField(encoding int8, b *codedBuffer) error {
var err error
switch encoding {
case proto.WireFixed32:
_, err = b.decodeFixed32()
case proto.WireFixed64:
_, err = b.decodeFixed64()
case proto.WireVarint:
_, err = b.decodeVarint()
case proto.WireBytes:
_, err = b.decodeRawBytes(false)
case proto.WireStartGroup:
var groupEnd int
groupEnd, _, err = skipGroup(b)
if err == nil {
b.index = groupEnd
}
default:
err = proto.ErrInternalBadWireType
}
if err != nil {
return err
}
return nil
}
func skipGroup(b *codedBuffer) (int, int, error) {
bs := b.buf
start := b.index
defer func() {
b.index = start
}()
for {
fieldStart := b.index
// read a field tag
_, wireType, err := b.decodeTagAndWireType()
if err != nil {
return 0, 0, err
}
// skip past the field's data
switch wireType {
case proto.WireFixed32:
if !b.skip(4) {
return 0, 0, io.ErrUnexpectedEOF
}
case proto.WireFixed64:
if !b.skip(8) {
return 0, 0, io.ErrUnexpectedEOF
}
case proto.WireVarint:
// skip varint by finding last byte (has high bit unset)
i := b.index
for {
if i >= len(bs) {
return 0, 0, io.ErrUnexpectedEOF
}
if bs[i]&0x80 == 0 {
break
}
i++
}
b.index++
case proto.WireBytes:
l, err := b.decodeVarint()
if err != nil {
return 0, 0, err
}
lInt := int(l)
if lInt < 0 {
return 0, 0, fmt.Errorf("proto: bad byte length %d", lInt)
}
if !b.skip(int(l)) {
return 0, 0, io.ErrUnexpectedEOF
}
case proto.WireStartGroup:
endIndex, _, err := skipGroup(b)
if err != nil {
return 0, 0, err
}
b.index = endIndex
case proto.WireEndGroup:
return b.index, fieldStart, nil
default:
return 0, 0, proto.ErrInternalBadWireType
}
}
}