128 lines
3.6 KiB
Go
128 lines
3.6 KiB
Go
// 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 bson
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import (
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"reflect"
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)
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// emptyInterfaceCodec is the Codec used for interface{} values.
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type emptyInterfaceCodec struct {
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// decodeBinaryAsSlice causes DecodeValue to unmarshal BSON binary field values that are the
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// "Generic" or "Old" BSON binary subtype as a Go byte slice instead of a Binary.
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decodeBinaryAsSlice bool
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}
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// Assert that emptyInterfaceCodec satisfies the typeDecoder interface, which allows it
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// to be used by collection type decoders (e.g. map, slice, etc) to set individual values in a
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// collection.
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var _ typeDecoder = &emptyInterfaceCodec{}
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// EncodeValue is the ValueEncoderFunc for interface{}.
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func (eic *emptyInterfaceCodec) EncodeValue(ec EncodeContext, vw 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 Type) (reflect.Type, error) {
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isDocument := valueType == Type(0) || valueType == TypeEmbeddedDocument
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if isDocument {
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if dc.defaultDocumentType != nil {
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// If the bsontype is an embedded document and the DocumentType is set on the DecodeContext, then return
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// that type.
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return dc.defaultDocumentType, nil
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}
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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 Type(0) or TypeEmbeddedDocument,
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// depending on the original valueType.
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var lookupType Type
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switch valueType {
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case Type(0):
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lookupType = TypeEmbeddedDocument
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case TypeEmbeddedDocument:
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lookupType = 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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// fallback to bson.D
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return tD, nil
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}
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return nil, err
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}
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func (eic *emptyInterfaceCodec) decodeType(dc DecodeContext, vr ValueReader, t reflect.Type) (reflect.Value, error) {
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if t != tEmpty {
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return emptyValue, ValueDecoderError{Name: "EmptyInterfaceDecodeValue", Types: []reflect.Type{tEmpty}, Received: reflect.Zero(t)}
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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 TypeNull:
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return reflect.Zero(t), vr.ReadNull()
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default:
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return emptyValue, 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 emptyValue, err
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}
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elem, err := decodeTypeOrValueWithInfo(decoder, dc, vr, rtype)
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if err != nil {
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return emptyValue, err
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}
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if (eic.decodeBinaryAsSlice || dc.binaryAsSlice) && rtype == tBinary {
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binElem := elem.Interface().(Binary)
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if binElem.Subtype == TypeBinaryGeneric || binElem.Subtype == TypeBinaryBinaryOld {
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elem = reflect.ValueOf(binElem.Data)
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}
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}
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return elem, nil
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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 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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elem, err := eic.decodeType(dc, vr, val.Type())
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if err != nil {
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return err
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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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