108 lines
2.9 KiB
Go
108 lines
2.9 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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"errors"
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"fmt"
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"reflect"
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)
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// stringCodec is the Codec used for string values.
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type stringCodec struct{}
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// Assert that stringCodec 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 = &stringCodec{}
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// EncodeValue is the ValueEncoder for string types.
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func (sc *stringCodec) EncodeValue(_ EncodeContext, vw ValueWriter, val reflect.Value) error {
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if val.Kind() != reflect.String {
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return ValueEncoderError{
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Name: "StringEncodeValue",
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Kinds: []reflect.Kind{reflect.String},
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Received: val,
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}
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}
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return vw.WriteString(val.String())
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}
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func (sc *stringCodec) decodeType(dc DecodeContext, vr ValueReader, t reflect.Type) (reflect.Value, error) {
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if t.Kind() != reflect.String {
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return emptyValue, ValueDecoderError{
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Name: "StringDecodeValue",
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Kinds: []reflect.Kind{reflect.String},
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Received: reflect.Zero(t),
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}
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}
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var str string
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var err error
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switch vr.Type() {
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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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case TypeObjectID:
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if dc.objectIDAsHexString {
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oid, err := vr.ReadObjectID()
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if err != nil {
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return emptyValue, err
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}
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str = oid.Hex()
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} else {
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const msg = "decoding an object ID into a string is not supported by default " +
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"(set Decoder.ObjectIDAsHexString to enable decoding as a hexadecimal string)"
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return emptyValue, errors.New(msg)
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}
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case TypeSymbol:
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str, 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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case TypeBinary:
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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: "string"}
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}
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str = string(data)
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case TypeNull:
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if err = vr.ReadNull(); err != nil {
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return emptyValue, err
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}
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case TypeUndefined:
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if err = vr.ReadUndefined(); err != nil {
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return emptyValue, err
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}
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default:
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return emptyValue, fmt.Errorf("cannot decode %v into a string type", vr.Type())
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}
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return reflect.ValueOf(str), nil
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}
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// DecodeValue is the ValueDecoder for string types.
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func (sc *stringCodec) DecodeValue(dctx DecodeContext, vr ValueReader, val reflect.Value) error {
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if !val.CanSet() || val.Kind() != reflect.String {
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return ValueDecoderError{Name: "StringDecodeValue", Kinds: []reflect.Kind{reflect.String}, Received: val}
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}
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elem, err := sc.decodeType(dctx, 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.SetString(elem.String())
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return nil
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}
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