98 lines
2.7 KiB
Go
98 lines
2.7 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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"fmt"
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"reflect"
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)
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// byteSliceCodec is the Codec used for []byte values.
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type byteSliceCodec struct {
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// encodeNilAsEmpty causes EncodeValue to marshal nil Go byte slices as empty BSON binary values
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// instead of BSON null.
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encodeNilAsEmpty bool
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}
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// Assert that byteSliceCodec satisfies the typeDecoder interface, which allows it to be
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// 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 = &byteSliceCodec{}
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// EncodeValue is the ValueEncoder for []byte.
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func (bsc *byteSliceCodec) EncodeValue(ec EncodeContext, vw ValueWriter, val reflect.Value) error {
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if !val.IsValid() || val.Type() != tByteSlice {
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return ValueEncoderError{Name: "ByteSliceEncodeValue", Types: []reflect.Type{tByteSlice}, Received: val}
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}
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if val.IsNil() && !bsc.encodeNilAsEmpty && !ec.nilByteSliceAsEmpty {
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return vw.WriteNull()
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}
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return vw.WriteBinary(val.Interface().([]byte))
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}
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func (bsc *byteSliceCodec) decodeType(_ DecodeContext, vr ValueReader, t reflect.Type) (reflect.Value, error) {
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if t != tByteSlice {
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return emptyValue, ValueDecoderError{
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Name: "ByteSliceDecodeValue",
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Types: []reflect.Type{tByteSlice},
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Received: reflect.Zero(t),
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}
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}
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var data []byte
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var err error
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switch vrType := vr.Type(); vrType {
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case TypeString:
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str, err := vr.ReadString()
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if err != nil {
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return emptyValue, err
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}
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data = []byte(str)
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case TypeSymbol:
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sym, err := vr.ReadSymbol()
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if err != nil {
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return emptyValue, err
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}
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data = []byte(sym)
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case TypeBinary:
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var subtype byte
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data, subtype, err = vr.ReadBinary()
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if err != nil {
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return emptyValue, err
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}
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if subtype != TypeBinaryGeneric && subtype != TypeBinaryBinaryOld {
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return emptyValue, decodeBinaryError{subtype: subtype, typeName: "[]byte"}
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}
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case TypeNull:
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err = vr.ReadNull()
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case TypeUndefined:
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err = vr.ReadUndefined()
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default:
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return emptyValue, fmt.Errorf("cannot decode %v into a []byte", vrType)
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}
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if err != nil {
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return emptyValue, err
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}
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return reflect.ValueOf(data), nil
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}
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// DecodeValue is the ValueDecoder for []byte.
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func (bsc *byteSliceCodec) DecodeValue(dc DecodeContext, vr ValueReader, val reflect.Value) error {
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if !val.CanSet() || val.Type() != tByteSlice {
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return ValueDecoderError{Name: "ByteSliceDecodeValue", Types: []reflect.Type{tByteSlice}, Received: val}
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}
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elem, err := bsc.decodeType(dc, vr, tByteSlice)
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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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