344 lines
10 KiB
Go
344 lines
10 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 bsoncodec
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import (
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"encoding"
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"errors"
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"fmt"
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"reflect"
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"strconv"
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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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)
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var defaultMapCodec = NewMapCodec()
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// MapCodec is the Codec used for map values.
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//
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// Deprecated: MapCodec will not be directly configurable in Go Driver 2.0. To
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// configure the map encode and decode behavior, use the configuration methods
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// on a [go.mongodb.org/mongo-driver/bson.Encoder] or
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// [go.mongodb.org/mongo-driver/bson.Decoder]. To configure the map encode and
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// decode behavior for a mongo.Client, use
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// [go.mongodb.org/mongo-driver/mongo/options.ClientOptions.SetBSONOptions].
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//
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// For example, to configure a mongo.Client to marshal nil Go maps as empty BSON
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// documents, use:
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//
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// opt := options.Client().SetBSONOptions(&options.BSONOptions{
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// NilMapAsEmpty: true,
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// })
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//
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// See the deprecation notice for each field in MapCodec for the corresponding
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// settings.
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type MapCodec struct {
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// DecodeZerosMap causes DecodeValue to delete any existing values from Go maps in the destination
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// value passed to Decode before unmarshaling BSON documents into them.
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//
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// Deprecated: Use bson.Decoder.ZeroMaps or options.BSONOptions.ZeroMaps instead.
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DecodeZerosMap bool
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// EncodeNilAsEmpty causes EncodeValue to marshal nil Go maps as empty BSON documents instead of
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// BSON null.
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//
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// Deprecated: Use bson.Encoder.NilMapAsEmpty or options.BSONOptions.NilMapAsEmpty instead.
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EncodeNilAsEmpty bool
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// EncodeKeysWithStringer causes the Encoder to convert Go map keys to BSON document field name
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// strings using fmt.Sprintf() instead of the default string conversion logic.
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//
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// Deprecated: Use bson.Encoder.StringifyMapKeysWithFmt or
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// options.BSONOptions.StringifyMapKeysWithFmt instead.
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EncodeKeysWithStringer bool
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}
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// KeyMarshaler is the interface implemented by an object that can marshal itself into a string key.
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// This applies to types used as map keys and is similar to encoding.TextMarshaler.
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type KeyMarshaler interface {
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MarshalKey() (key string, err error)
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}
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// KeyUnmarshaler is the interface implemented by an object that can unmarshal a string representation
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// of itself. This applies to types used as map keys and is similar to encoding.TextUnmarshaler.
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//
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// UnmarshalKey must be able to decode the form generated by MarshalKey.
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// UnmarshalKey must copy the text if it wishes to retain the text
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// after returning.
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type KeyUnmarshaler interface {
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UnmarshalKey(key string) error
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}
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// NewMapCodec returns a MapCodec with options opts.
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//
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// Deprecated: NewMapCodec will not be available in Go Driver 2.0. See
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// [MapCodec] for more details.
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func NewMapCodec(opts ...*bsonoptions.MapCodecOptions) *MapCodec {
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mapOpt := bsonoptions.MergeMapCodecOptions(opts...)
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codec := MapCodec{}
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if mapOpt.DecodeZerosMap != nil {
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codec.DecodeZerosMap = *mapOpt.DecodeZerosMap
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}
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if mapOpt.EncodeNilAsEmpty != nil {
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codec.EncodeNilAsEmpty = *mapOpt.EncodeNilAsEmpty
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}
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if mapOpt.EncodeKeysWithStringer != nil {
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codec.EncodeKeysWithStringer = *mapOpt.EncodeKeysWithStringer
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}
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return &codec
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}
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// EncodeValue is the ValueEncoder for map[*]* types.
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func (mc *MapCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
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if !val.IsValid() || val.Kind() != reflect.Map {
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return ValueEncoderError{Name: "MapEncodeValue", Kinds: []reflect.Kind{reflect.Map}, Received: val}
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}
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if val.IsNil() && !mc.EncodeNilAsEmpty && !ec.nilMapAsEmpty {
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// If we have a nil map but we can't WriteNull, that means we're probably trying to encode
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// to a TopLevel document. We can't currently tell if this is what actually happened, but if
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// there's a deeper underlying problem, the error will also be returned from WriteDocument,
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// so just continue. The operations on a map reflection value are valid, so we can call
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// MapKeys within mapEncodeValue without a problem.
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err := vw.WriteNull()
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if err == nil {
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return nil
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}
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}
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dw, err := vw.WriteDocument()
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if err != nil {
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return err
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}
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return mc.mapEncodeValue(ec, dw, val, nil)
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}
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// mapEncodeValue handles encoding of the values of a map. The collisionFn returns
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// true if the provided key exists, this is mainly used for inline maps in the
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// struct codec.
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func (mc *MapCodec) mapEncodeValue(ec EncodeContext, dw bsonrw.DocumentWriter, val reflect.Value, collisionFn func(string) bool) error {
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elemType := val.Type().Elem()
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encoder, err := ec.LookupEncoder(elemType)
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if err != nil && elemType.Kind() != reflect.Interface {
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return err
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}
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keys := val.MapKeys()
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for _, key := range keys {
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keyStr, err := mc.encodeKey(key, ec.stringifyMapKeysWithFmt)
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if err != nil {
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return err
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}
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if collisionFn != nil && collisionFn(keyStr) {
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return fmt.Errorf("Key %s of inlined map conflicts with a struct field name", key)
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}
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currEncoder, currVal, lookupErr := defaultValueEncoders.lookupElementEncoder(ec, encoder, val.MapIndex(key))
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if lookupErr != nil && !errors.Is(lookupErr, errInvalidValue) {
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return lookupErr
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}
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vw, err := dw.WriteDocumentElement(keyStr)
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if err != nil {
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return err
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}
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if errors.Is(lookupErr, errInvalidValue) {
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err = vw.WriteNull()
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if err != nil {
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return err
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}
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continue
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}
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err = currEncoder.EncodeValue(ec, vw, currVal)
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if err != nil {
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return err
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}
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}
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return dw.WriteDocumentEnd()
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}
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// DecodeValue is the ValueDecoder for map[string/decimal]* types.
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func (mc *MapCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
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if val.Kind() != reflect.Map || (!val.CanSet() && val.IsNil()) {
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return ValueDecoderError{Name: "MapDecodeValue", Kinds: []reflect.Kind{reflect.Map}, Received: val}
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}
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switch vrType := vr.Type(); vrType {
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case bsontype.Type(0), bsontype.EmbeddedDocument:
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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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case bsontype.Undefined:
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val.Set(reflect.Zero(val.Type()))
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return vr.ReadUndefined()
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default:
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return fmt.Errorf("cannot decode %v into a %s", vrType, val.Type())
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}
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dr, err := vr.ReadDocument()
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if err != nil {
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return err
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}
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if val.IsNil() {
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val.Set(reflect.MakeMap(val.Type()))
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}
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if val.Len() > 0 && (mc.DecodeZerosMap || dc.zeroMaps) {
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clearMap(val)
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}
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eType := val.Type().Elem()
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decoder, err := dc.LookupDecoder(eType)
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if err != nil {
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return err
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}
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eTypeDecoder, _ := decoder.(typeDecoder)
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if eType == tEmpty {
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dc.Ancestor = val.Type()
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}
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keyType := val.Type().Key()
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for {
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key, vr, err := dr.ReadElement()
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if errors.Is(err, bsonrw.ErrEOD) {
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break
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}
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if err != nil {
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return err
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}
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k, err := mc.decodeKey(key, keyType)
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if err != nil {
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return err
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}
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elem, err := decodeTypeOrValueWithInfo(decoder, eTypeDecoder, dc, vr, eType, true)
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if err != nil {
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return newDecodeError(key, err)
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}
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val.SetMapIndex(k, elem)
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}
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return nil
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}
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func clearMap(m reflect.Value) {
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var none reflect.Value
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for _, k := range m.MapKeys() {
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m.SetMapIndex(k, none)
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}
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}
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func (mc *MapCodec) encodeKey(val reflect.Value, encodeKeysWithStringer bool) (string, error) {
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if mc.EncodeKeysWithStringer || encodeKeysWithStringer {
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return fmt.Sprint(val), nil
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}
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// keys of any string type are used directly
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if val.Kind() == reflect.String {
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return val.String(), nil
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}
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// KeyMarshalers are marshaled
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if km, ok := val.Interface().(KeyMarshaler); ok {
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if val.Kind() == reflect.Ptr && val.IsNil() {
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return "", nil
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}
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buf, err := km.MarshalKey()
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if err == nil {
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return buf, nil
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}
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return "", err
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}
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// keys implement encoding.TextMarshaler are marshaled.
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if km, ok := val.Interface().(encoding.TextMarshaler); ok {
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if val.Kind() == reflect.Ptr && val.IsNil() {
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return "", nil
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}
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buf, err := km.MarshalText()
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if err != nil {
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return "", err
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}
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return string(buf), nil
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}
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switch val.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return strconv.FormatInt(val.Int(), 10), nil
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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return strconv.FormatUint(val.Uint(), 10), nil
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}
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return "", fmt.Errorf("unsupported key type: %v", val.Type())
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}
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var keyUnmarshalerType = reflect.TypeOf((*KeyUnmarshaler)(nil)).Elem()
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var textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
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func (mc *MapCodec) decodeKey(key string, keyType reflect.Type) (reflect.Value, error) {
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keyVal := reflect.ValueOf(key)
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var err error
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switch {
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// First, if EncodeKeysWithStringer is not enabled, try to decode withKeyUnmarshaler
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case !mc.EncodeKeysWithStringer && reflect.PtrTo(keyType).Implements(keyUnmarshalerType):
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keyVal = reflect.New(keyType)
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v := keyVal.Interface().(KeyUnmarshaler)
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err = v.UnmarshalKey(key)
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keyVal = keyVal.Elem()
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// Try to decode encoding.TextUnmarshalers.
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case reflect.PtrTo(keyType).Implements(textUnmarshalerType):
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keyVal = reflect.New(keyType)
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v := keyVal.Interface().(encoding.TextUnmarshaler)
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err = v.UnmarshalText([]byte(key))
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keyVal = keyVal.Elem()
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// Otherwise, go to type specific behavior
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default:
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switch keyType.Kind() {
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case reflect.String:
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keyVal = reflect.ValueOf(key).Convert(keyType)
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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n, parseErr := strconv.ParseInt(key, 10, 64)
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if parseErr != nil || reflect.Zero(keyType).OverflowInt(n) {
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err = fmt.Errorf("failed to unmarshal number key %v", key)
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}
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keyVal = reflect.ValueOf(n).Convert(keyType)
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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n, parseErr := strconv.ParseUint(key, 10, 64)
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if parseErr != nil || reflect.Zero(keyType).OverflowUint(n) {
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err = fmt.Errorf("failed to unmarshal number key %v", key)
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break
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}
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keyVal = reflect.ValueOf(n).Convert(keyType)
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case reflect.Float32, reflect.Float64:
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if mc.EncodeKeysWithStringer {
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parsed, err := strconv.ParseFloat(key, 64)
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if err != nil {
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return keyVal, fmt.Errorf("Map key is defined to be a decimal type (%v) but got error %w", keyType.Kind(), err)
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}
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keyVal = reflect.ValueOf(parsed)
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break
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}
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fallthrough
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default:
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return keyVal, fmt.Errorf("unsupported key type: %v", keyType)
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}
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}
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return keyVal, err
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}
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