goext/mongo/bson/bsoncodec/string_codec.go

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2023-06-18 15:50:55 +02:00
// 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"
)
// StringCodec is the Codec used for struct values.
type StringCodec struct {
DecodeObjectIDAsHex bool
}
var (
defaultStringCodec = NewStringCodec()
_ ValueCodec = defaultStringCodec
_ typeDecoder = defaultStringCodec
)
// NewStringCodec returns a StringCodec with options opts.
func NewStringCodec(opts ...*bsonoptions.StringCodecOptions) *StringCodec {
stringOpt := bsonoptions.MergeStringCodecOptions(opts...)
return &StringCodec{*stringOpt.DecodeObjectIDAsHex}
}
// EncodeValue is the ValueEncoder for string types.
func (sc *StringCodec) EncodeValue(ectx EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
if val.Kind() != reflect.String {
return ValueEncoderError{
Name: "StringEncodeValue",
Kinds: []reflect.Kind{reflect.String},
Received: val,
}
}
return vw.WriteString(val.String())
}
func (sc *StringCodec) decodeType(dc DecodeContext, vr bsonrw.ValueReader, t reflect.Type) (reflect.Value, error) {
if t.Kind() != reflect.String {
return emptyValue, ValueDecoderError{
Name: "StringDecodeValue",
Kinds: []reflect.Kind{reflect.String},
Received: reflect.Zero(t),
}
}
var str string
var err error
switch vr.Type() {
case bsontype.String:
str, err = vr.ReadString()
if err != nil {
return emptyValue, err
}
case bsontype.ObjectID:
oid, err := vr.ReadObjectID()
if err != nil {
return emptyValue, err
}
if sc.DecodeObjectIDAsHex {
str = oid.Hex()
} else {
byteArray := [12]byte(oid)
str = string(byteArray[:])
}
case bsontype.Symbol:
str, err = vr.ReadSymbol()
if err != nil {
return emptyValue, err
}
case bsontype.Binary:
data, subtype, err := vr.ReadBinary()
if err != nil {
return emptyValue, err
}
if subtype != bsontype.BinaryGeneric && subtype != bsontype.BinaryBinaryOld {
return emptyValue, decodeBinaryError{subtype: subtype, typeName: "string"}
}
str = string(data)
case bsontype.Null:
if err = vr.ReadNull(); err != nil {
return emptyValue, err
}
case bsontype.Undefined:
if err = vr.ReadUndefined(); err != nil {
return emptyValue, err
}
default:
return emptyValue, fmt.Errorf("cannot decode %v into a string type", vr.Type())
}
return reflect.ValueOf(str), nil
}
// DecodeValue is the ValueDecoder for string types.
func (sc *StringCodec) DecodeValue(dctx DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
if !val.CanSet() || val.Kind() != reflect.String {
return ValueDecoderError{Name: "StringDecodeValue", Kinds: []reflect.Kind{reflect.String}, Received: val}
}
elem, err := sc.decodeType(dctx, vr, val.Type())
if err != nil {
return err
}
val.SetString(elem.String())
return nil
}