/
byte_slice_codec.go
138 lines (124 loc) · 4.29 KB
/
byte_slice_codec.go
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// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package bsoncodec
import (
"fmt"
"reflect"
"go.mongodb.org/mongo-driver/bson/bsonoptions"
"go.mongodb.org/mongo-driver/bson/bsonrw"
"go.mongodb.org/mongo-driver/bson/bsontype"
)
// ByteSliceCodec is the Codec used for []byte values.
//
// Deprecated: ByteSliceCodec will not be directly configurable in Go Driver
// 2.0. To configure the byte slice encode and decode behavior, use the
// configuration methods on a [go.mongodb.org/mongo-driver/bson.Encoder] or
// [go.mongodb.org/mongo-driver/bson.Decoder]. To configure the byte slice
// encode and decode behavior for a mongo.Client, use
// [go.mongodb.org/mongo-driver/mongo/options.ClientOptions.SetBSONOptions].
//
// For example, to configure a mongo.Client to encode nil byte slices as empty
// BSON binary values, use:
//
// opt := options.Client().SetBSONOptions(&options.BSONOptions{
// NilByteSliceAsEmpty: true,
// })
//
// See the deprecation notice for each field in ByteSliceCodec for the
// corresponding settings.
type ByteSliceCodec struct {
// EncodeNilAsEmpty causes EncodeValue to marshal nil Go byte slices as empty BSON binary values
// instead of BSON null.
//
// Deprecated: Use bson.Encoder.NilByteSliceAsEmpty or options.BSONOptions.NilByteSliceAsEmpty
// instead.
EncodeNilAsEmpty bool
}
var (
defaultByteSliceCodec = NewByteSliceCodec()
// Assert that defaultByteSliceCodec satisfies the typeDecoder interface, which allows it to be
// used by collection type decoders (e.g. map, slice, etc) to set individual values in a
// collection.
_ typeDecoder = defaultByteSliceCodec
)
// NewByteSliceCodec returns a ByteSliceCodec with options opts.
//
// Deprecated: NewByteSliceCodec will not be available in Go Driver 2.0. See
// [ByteSliceCodec] for more details.
func NewByteSliceCodec(opts ...*bsonoptions.ByteSliceCodecOptions) *ByteSliceCodec {
byteSliceOpt := bsonoptions.MergeByteSliceCodecOptions(opts...)
codec := ByteSliceCodec{}
if byteSliceOpt.EncodeNilAsEmpty != nil {
codec.EncodeNilAsEmpty = *byteSliceOpt.EncodeNilAsEmpty
}
return &codec
}
// EncodeValue is the ValueEncoder for []byte.
func (bsc *ByteSliceCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
if !val.IsValid() || val.Type() != tByteSlice {
return ValueEncoderError{Name: "ByteSliceEncodeValue", Types: []reflect.Type{tByteSlice}, Received: val}
}
if val.IsNil() && !bsc.EncodeNilAsEmpty && !ec.nilByteSliceAsEmpty {
return vw.WriteNull()
}
return vw.WriteBinary(val.Interface().([]byte))
}
func (bsc *ByteSliceCodec) decodeType(_ DecodeContext, vr bsonrw.ValueReader, t reflect.Type) (reflect.Value, error) {
if t != tByteSlice {
return emptyValue, ValueDecoderError{
Name: "ByteSliceDecodeValue",
Types: []reflect.Type{tByteSlice},
Received: reflect.Zero(t),
}
}
var data []byte
var err error
switch vrType := vr.Type(); vrType {
case bsontype.String:
str, err := vr.ReadString()
if err != nil {
return emptyValue, err
}
data = []byte(str)
case bsontype.Symbol:
sym, err := vr.ReadSymbol()
if err != nil {
return emptyValue, err
}
data = []byte(sym)
case bsontype.Binary:
var subtype byte
data, subtype, err = vr.ReadBinary()
if err != nil {
return emptyValue, err
}
if subtype != bsontype.BinaryGeneric && subtype != bsontype.BinaryBinaryOld {
return emptyValue, decodeBinaryError{subtype: subtype, typeName: "[]byte"}
}
case bsontype.Null:
err = vr.ReadNull()
case bsontype.Undefined:
err = vr.ReadUndefined()
default:
return emptyValue, fmt.Errorf("cannot decode %v into a []byte", vrType)
}
if err != nil {
return emptyValue, err
}
return reflect.ValueOf(data), nil
}
// DecodeValue is the ValueDecoder for []byte.
func (bsc *ByteSliceCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
if !val.CanSet() || val.Type() != tByteSlice {
return ValueDecoderError{Name: "ByteSliceDecodeValue", Types: []reflect.Type{tByteSlice}, Received: val}
}
elem, err := bsc.decodeType(dc, vr, tByteSlice)
if err != nil {
return err
}
val.Set(elem)
return nil
}