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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 (
"reflect"
"go.mongodb.org/mongo-driver/bson/bsonoptions"
"go.mongodb.org/mongo-driver/bson/bsonrw"
"go.mongodb.org/mongo-driver/bson/bsontype"
"go.mongodb.org/mongo-driver/bson/primitive"
)
// EmptyInterfaceCodec is the Codec used for interface{} values.
type EmptyInterfaceCodec struct {
DecodeBinaryAsSlice bool
}
var (
defaultEmptyInterfaceCodec = NewEmptyInterfaceCodec()
_ ValueCodec = defaultEmptyInterfaceCodec
_ typeDecoder = defaultEmptyInterfaceCodec
)
// NewEmptyInterfaceCodec returns a EmptyInterfaceCodec with options opts.
func NewEmptyInterfaceCodec(opts ...*bsonoptions.EmptyInterfaceCodecOptions) *EmptyInterfaceCodec {
interfaceOpt := bsonoptions.MergeEmptyInterfaceCodecOptions(opts...)
codec := EmptyInterfaceCodec{}
if interfaceOpt.DecodeBinaryAsSlice != nil {
codec.DecodeBinaryAsSlice = *interfaceOpt.DecodeBinaryAsSlice
}
return &codec
}
// EncodeValue is the ValueEncoderFunc for interface{}.
func (eic EmptyInterfaceCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
if !val.IsValid() || val.Type() != tEmpty {
return ValueEncoderError{Name: "EmptyInterfaceEncodeValue", Types: []reflect.Type{tEmpty}, Received: val}
}
if val.IsNil() {
return vw.WriteNull()
}
encoder, err := ec.LookupEncoder(val.Elem().Type())
if err != nil {
return err
}
return encoder.EncodeValue(ec, vw, val.Elem())
}
func (eic EmptyInterfaceCodec) getEmptyInterfaceDecodeType(dc DecodeContext, valueType bsontype.Type) (reflect.Type, error) {
isDocument := valueType == bsontype.Type(0) || valueType == bsontype.EmbeddedDocument
if isDocument && dc.Ancestor != nil {
// Using ancestor information rather than looking up the type map entry forces consistent decoding.
// If we're decoding into a bson.D, subdocuments should also be decoded as bson.D, even if a type map entry
// has been registered.
return dc.Ancestor, nil
}
rtype, err := dc.LookupTypeMapEntry(valueType)
if err == nil {
return rtype, nil
}
if isDocument {
// For documents, fallback to looking up a type map entry for bsontype.Type(0) or bsontype.EmbeddedDocument,
// depending on the original valueType.
var lookupType bsontype.Type
switch valueType {
case bsontype.Type(0):
lookupType = bsontype.EmbeddedDocument
case bsontype.EmbeddedDocument:
lookupType = bsontype.Type(0)
}
rtype, err = dc.LookupTypeMapEntry(lookupType)
if err == nil {
return rtype, nil
}
}
return nil, err
}
func (eic EmptyInterfaceCodec) decodeType(dc DecodeContext, vr bsonrw.ValueReader, t reflect.Type) (reflect.Value, error) {
if t != tEmpty {
return emptyValue, ValueDecoderError{Name: "EmptyInterfaceDecodeValue", Types: []reflect.Type{tEmpty}, Received: reflect.Zero(t)}
}
rtype, err := eic.getEmptyInterfaceDecodeType(dc, vr.Type())
if err != nil {
switch vr.Type() {
case bsontype.Null:
return reflect.Zero(t), vr.ReadNull()
default:
return emptyValue, err
}
}
decoder, err := dc.LookupDecoder(rtype)
if err != nil {
return emptyValue, err
}
elem, err := decodeTypeOrValue(decoder, dc, vr, rtype)
if err != nil {
return emptyValue, err
}
if eic.DecodeBinaryAsSlice && rtype == tBinary {
binElem := elem.Interface().(primitive.Binary)
if binElem.Subtype == bsontype.BinaryGeneric || binElem.Subtype == bsontype.BinaryBinaryOld {
elem = reflect.ValueOf(binElem.Data)
}
}
return elem, nil
}
// DecodeValue is the ValueDecoderFunc for interface{}.
func (eic EmptyInterfaceCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
if !val.CanSet() || val.Type() != tEmpty {
return ValueDecoderError{Name: "EmptyInterfaceDecodeValue", Types: []reflect.Type{tEmpty}, Received: val}
}
elem, err := eic.decodeType(dc, vr, val.Type())
if err != nil {
return err
}
val.Set(elem)
return nil
}
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