126 lines
3.6 KiB
Go
126 lines
3.6 KiB
Go
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// Copyright (C) MongoDB, Inc. 2017-present.
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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package bsoncodec
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import (
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"reflect"
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"go.mongodb.org/mongo-driver/bson/bsonoptions"
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"go.mongodb.org/mongo-driver/bson/bsonrw"
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"go.mongodb.org/mongo-driver/bson/bsontype"
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"go.mongodb.org/mongo-driver/bson/primitive"
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)
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var defaultEmptyInterfaceCodec = NewEmptyInterfaceCodec()
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// EmptyInterfaceCodec is the Codec used for interface{} values.
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type EmptyInterfaceCodec struct {
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DecodeBinaryAsSlice bool
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}
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var _ ValueCodec = &EmptyInterfaceCodec{}
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// NewEmptyInterfaceCodec returns a EmptyInterfaceCodec with options opts.
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func NewEmptyInterfaceCodec(opts ...*bsonoptions.EmptyInterfaceCodecOptions) *EmptyInterfaceCodec {
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interfaceOpt := bsonoptions.MergeEmptyInterfaceCodecOptions(opts...)
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codec := EmptyInterfaceCodec{}
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if interfaceOpt.DecodeBinaryAsSlice != nil {
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codec.DecodeBinaryAsSlice = *interfaceOpt.DecodeBinaryAsSlice
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}
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return &codec
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}
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// EncodeValue is the ValueEncoderFunc for interface{}.
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func (eic EmptyInterfaceCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
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if !val.IsValid() || val.Type() != tEmpty {
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return ValueEncoderError{Name: "EmptyInterfaceEncodeValue", Types: []reflect.Type{tEmpty}, Received: val}
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}
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if val.IsNil() {
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return vw.WriteNull()
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}
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encoder, err := ec.LookupEncoder(val.Elem().Type())
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if err != nil {
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return err
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}
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return encoder.EncodeValue(ec, vw, val.Elem())
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}
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func (eic EmptyInterfaceCodec) getEmptyInterfaceDecodeType(dc DecodeContext, valueType bsontype.Type) (reflect.Type, error) {
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isDocument := valueType == bsontype.Type(0) || valueType == bsontype.EmbeddedDocument
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if isDocument && dc.Ancestor != nil {
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// Using ancestor information rather than looking up the type map entry forces consistent decoding.
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// If we're decoding into a bson.D, subdocuments should also be decoded as bson.D, even if a type map entry
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// has been registered.
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return dc.Ancestor, nil
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}
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rtype, err := dc.LookupTypeMapEntry(valueType)
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if err == nil {
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return rtype, nil
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}
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if isDocument {
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// For documents, fallback to looking up a type map entry for bsontype.Type(0) or bsontype.EmbeddedDocument,
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// depending on the original valueType.
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var lookupType bsontype.Type
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switch valueType {
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case bsontype.Type(0):
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lookupType = bsontype.EmbeddedDocument
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case bsontype.EmbeddedDocument:
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lookupType = bsontype.Type(0)
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}
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rtype, err = dc.LookupTypeMapEntry(lookupType)
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if err == nil {
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return rtype, nil
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}
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}
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return nil, err
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}
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// DecodeValue is the ValueDecoderFunc for interface{}.
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func (eic EmptyInterfaceCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
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if !val.CanSet() || val.Type() != tEmpty {
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return ValueDecoderError{Name: "EmptyInterfaceDecodeValue", Types: []reflect.Type{tEmpty}, Received: val}
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}
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rtype, err := eic.getEmptyInterfaceDecodeType(dc, vr.Type())
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if err != nil {
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switch vr.Type() {
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case bsontype.Null:
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val.Set(reflect.Zero(val.Type()))
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return vr.ReadNull()
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default:
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return err
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}
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}
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decoder, err := dc.LookupDecoder(rtype)
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if err != nil {
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return err
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}
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elem := reflect.New(rtype).Elem()
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err = decoder.DecodeValue(dc, vr, elem)
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if err != nil {
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return err
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}
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if eic.DecodeBinaryAsSlice && rtype == tBinary {
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binElem := elem.Interface().(primitive.Binary)
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if binElem.Subtype == bsontype.BinaryGeneric || binElem.Subtype == bsontype.BinaryBinaryOld {
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elem = reflect.ValueOf(binElem.Data)
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}
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}
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val.Set(elem)
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return nil
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}
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