forked from ruiaylin/pgparser
/
marshaler.go
92 lines (80 loc) · 2.95 KB
/
marshaler.go
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// Copyright 2016 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0, included in the file
// licenses/APL.txt.
package protoutil
import (
"io"
"io/ioutil"
"github.com/cockroachdb/errors"
"github.com/gogo/protobuf/proto"
gwruntime "github.com/grpc-ecosystem/grpc-gateway/runtime"
)
var _ gwruntime.Marshaler = (*ProtoPb)(nil)
// ProtoPb is a gwruntime.Marshaler that uses github.com/gogo/protobuf/proto.
type ProtoPb struct{}
// ContentType implements gwruntime.Marshaler.
func (*ProtoPb) ContentType() string {
// NB: This is the same as httputil.ProtoContentType which we can't use due
// to an import cycle.
const ProtoContentType = "application/x-protobuf"
return ProtoContentType
}
// Marshal implements gwruntime.Marshaler.
func (*ProtoPb) Marshal(v interface{}) ([]byte, error) {
// NB: we use proto.Message here because grpc-gateway passes us protos that
// we don't control and thus don't implement protoutil.Message.
if p, ok := v.(proto.Message); ok {
return proto.Marshal(p)
}
return nil, errors.Errorf("unexpected type %T does not implement %s", v, typeProtoMessage)
}
// Unmarshal implements gwruntime.Marshaler.
func (*ProtoPb) Unmarshal(data []byte, v interface{}) error {
// NB: we use proto.Message here because grpc-gateway passes us protos that
// we don't control and thus don't implement protoutil.Message.
if p, ok := v.(proto.Message); ok {
return proto.Unmarshal(data, p)
}
return errors.Errorf("unexpected type %T does not implement %s", v, typeProtoMessage)
}
// NewDecoder implements gwruntime.Marshaler.
func (*ProtoPb) NewDecoder(r io.Reader) gwruntime.Decoder {
return gwruntime.DecoderFunc(func(v interface{}) error {
// NB: we use proto.Message here because grpc-gateway passes us protos that
// we don't control and thus don't implement protoutil.Message.
if p, ok := v.(proto.Message); ok {
bytes, err := ioutil.ReadAll(r)
if err == nil {
err = proto.Unmarshal(bytes, p)
}
return err
}
return errors.Errorf("unexpected type %T does not implement %s", v, typeProtoMessage)
})
}
// NewEncoder implements gwruntime.Marshaler.
func (*ProtoPb) NewEncoder(w io.Writer) gwruntime.Encoder {
return gwruntime.EncoderFunc(func(v interface{}) error {
// NB: we use proto.Message here because grpc-gateway passes us protos that
// we don't control and thus don't implement protoutil.Message.
if p, ok := v.(proto.Message); ok {
bytes, err := proto.Marshal(p)
if err == nil {
_, err = w.Write(bytes)
}
return err
}
return errors.Errorf("unexpected type %T does not implement %s", v, typeProtoMessage)
})
}
var _ gwruntime.Delimited = (*ProtoPb)(nil)
// Delimiter implements gwruntime.Delimited.
func (*ProtoPb) Delimiter() []byte {
return nil
}