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gitea/vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/map_codec.go

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8.3 KiB
Go

// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package bsoncodec
import (
"fmt"
"reflect"
"strconv"
"go.mongodb.org/mongo-driver/bson/bsonoptions"
"go.mongodb.org/mongo-driver/bson/bsonrw"
"go.mongodb.org/mongo-driver/bson/bsontype"
)
var defaultMapCodec = NewMapCodec()
// MapCodec is the Codec used for map values.
type MapCodec struct {
DecodeZerosMap bool
EncodeNilAsEmpty bool
EncodeKeysWithStringer bool
}
var _ ValueCodec = &MapCodec{}
// KeyMarshaler is the interface implemented by an object that can marshal itself into a string key.
// This applies to types used as map keys and is similar to encoding.TextMarshaler.
type KeyMarshaler interface {
MarshalKey() (key string, err error)
}
// KeyUnmarshaler is the interface implemented by an object that can unmarshal a string representation
// of itself. This applies to types used as map keys and is similar to encoding.TextUnmarshaler.
//
// UnmarshalKey must be able to decode the form generated by MarshalKey.
// UnmarshalKey must copy the text if it wishes to retain the text
// after returning.
type KeyUnmarshaler interface {
UnmarshalKey(key string) error
}
// NewMapCodec returns a MapCodec with options opts.
func NewMapCodec(opts ...*bsonoptions.MapCodecOptions) *MapCodec {
mapOpt := bsonoptions.MergeMapCodecOptions(opts...)
codec := MapCodec{}
if mapOpt.DecodeZerosMap != nil {
codec.DecodeZerosMap = *mapOpt.DecodeZerosMap
}
if mapOpt.EncodeNilAsEmpty != nil {
codec.EncodeNilAsEmpty = *mapOpt.EncodeNilAsEmpty
}
if mapOpt.EncodeKeysWithStringer != nil {
codec.EncodeKeysWithStringer = *mapOpt.EncodeKeysWithStringer
}
return &codec
}
// EncodeValue is the ValueEncoder for map[*]* types.
func (mc *MapCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
if !val.IsValid() || val.Kind() != reflect.Map {
return ValueEncoderError{Name: "MapEncodeValue", Kinds: []reflect.Kind{reflect.Map}, Received: val}
}
if val.IsNil() && !mc.EncodeNilAsEmpty {
// If we have a nil map but we can't WriteNull, that means we're probably trying to encode
// to a TopLevel document. We can't currently tell if this is what actually happened, but if
// there's a deeper underlying problem, the error will also be returned from WriteDocument,
// so just continue. The operations on a map reflection value are valid, so we can call
// MapKeys within mapEncodeValue without a problem.
err := vw.WriteNull()
if err == nil {
return nil
}
}
dw, err := vw.WriteDocument()
if err != nil {
return err
}
return mc.mapEncodeValue(ec, dw, val, nil)
}
// mapEncodeValue handles encoding of the values of a map. The collisionFn returns
// true if the provided key exists, this is mainly used for inline maps in the
// struct codec.
func (mc *MapCodec) mapEncodeValue(ec EncodeContext, dw bsonrw.DocumentWriter, val reflect.Value, collisionFn func(string) bool) error {
elemType := val.Type().Elem()
encoder, err := ec.LookupEncoder(elemType)
if err != nil && elemType.Kind() != reflect.Interface {
return err
}
keys := val.MapKeys()
for _, key := range keys {
keyStr, err := mc.encodeKey(key)
if err != nil {
return err
}
if collisionFn != nil && collisionFn(keyStr) {
return fmt.Errorf("Key %s of inlined map conflicts with a struct field name", key)
}
currEncoder, currVal, lookupErr := defaultValueEncoders.lookupElementEncoder(ec, encoder, val.MapIndex(key))
if lookupErr != nil && lookupErr != errInvalidValue {
return lookupErr
}
vw, err := dw.WriteDocumentElement(keyStr)
if err != nil {
return err
}
if lookupErr == errInvalidValue {
err = vw.WriteNull()
if err != nil {
return err
}
continue
}
if enc, ok := currEncoder.(ValueEncoder); ok {
err = enc.EncodeValue(ec, vw, currVal)
if err != nil {
return err
}
continue
}
err = encoder.EncodeValue(ec, vw, currVal)
if err != nil {
return err
}
}
return dw.WriteDocumentEnd()
}
// DecodeValue is the ValueDecoder for map[string/decimal]* types.
func (mc *MapCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
if val.Kind() != reflect.Map || (!val.CanSet() && val.IsNil()) {
return ValueDecoderError{Name: "MapDecodeValue", Kinds: []reflect.Kind{reflect.Map}, Received: val}
}
switch vrType := vr.Type(); vrType {
case bsontype.Type(0), bsontype.EmbeddedDocument:
case bsontype.Null:
val.Set(reflect.Zero(val.Type()))
return vr.ReadNull()
case bsontype.Undefined:
val.Set(reflect.Zero(val.Type()))
return vr.ReadUndefined()
default:
return fmt.Errorf("cannot decode %v into a %s", vrType, val.Type())
}
dr, err := vr.ReadDocument()
if err != nil {
return err
}
if val.IsNil() {
val.Set(reflect.MakeMap(val.Type()))
}
if val.Len() > 0 && mc.DecodeZerosMap {
clearMap(val)
}
eType := val.Type().Elem()
decoder, err := dc.LookupDecoder(eType)
if err != nil {
return err
}
eTypeDecoder, _ := decoder.(typeDecoder)
if eType == tEmpty {
dc.Ancestor = val.Type()
}
keyType := val.Type().Key()
for {
key, vr, err := dr.ReadElement()
if err == bsonrw.ErrEOD {
break
}
if err != nil {
return err
}
k, err := mc.decodeKey(key, keyType)
if err != nil {
return err
}
elem, err := decodeTypeOrValueWithInfo(decoder, eTypeDecoder, dc, vr, eType, true)
if err != nil {
return newDecodeError(key, err)
}
val.SetMapIndex(k, elem)
}
return nil
}
func clearMap(m reflect.Value) {
var none reflect.Value
for _, k := range m.MapKeys() {
m.SetMapIndex(k, none)
}
}
func (mc *MapCodec) encodeKey(val reflect.Value) (string, error) {
if mc.EncodeKeysWithStringer {
return fmt.Sprint(val), nil
}
// keys of any string type are used directly
if val.Kind() == reflect.String {
return val.String(), nil
}
// KeyMarshalers are marshaled
if km, ok := val.Interface().(KeyMarshaler); ok {
if val.Kind() == reflect.Ptr && val.IsNil() {
return "", nil
}
buf, err := km.MarshalKey()
if err == nil {
return buf, nil
}
return "", err
}
switch val.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return strconv.FormatInt(val.Int(), 10), nil
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return strconv.FormatUint(val.Uint(), 10), nil
}
return "", fmt.Errorf("unsupported key type: %v", val.Type())
}
var keyUnmarshalerType = reflect.TypeOf((*KeyUnmarshaler)(nil)).Elem()
func (mc *MapCodec) decodeKey(key string, keyType reflect.Type) (reflect.Value, error) {
keyVal := reflect.ValueOf(key)
var err error
switch {
// First, if EncodeKeysWithStringer is not enabled, try to decode withKeyUnmarshaler
case !mc.EncodeKeysWithStringer && reflect.PtrTo(keyType).Implements(keyUnmarshalerType):
keyVal = reflect.New(keyType)
v := keyVal.Interface().(KeyUnmarshaler)
err = v.UnmarshalKey(key)
keyVal = keyVal.Elem()
// Otherwise, go to type specific behavior
default:
switch keyType.Kind() {
case reflect.String:
keyVal = reflect.ValueOf(key).Convert(keyType)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
s := string(key)
n, parseErr := strconv.ParseInt(s, 10, 64)
if parseErr != nil || reflect.Zero(keyType).OverflowInt(n) {
err = fmt.Errorf("failed to unmarshal number key %v", s)
}
keyVal = reflect.ValueOf(n).Convert(keyType)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
s := string(key)
n, parseErr := strconv.ParseUint(s, 10, 64)
if parseErr != nil || reflect.Zero(keyType).OverflowUint(n) {
err = fmt.Errorf("failed to unmarshal number key %v", s)
break
}
keyVal = reflect.ValueOf(n).Convert(keyType)
case reflect.Float32, reflect.Float64:
if mc.EncodeKeysWithStringer {
parsed, err := strconv.ParseFloat(key, 64)
if err != nil {
return keyVal, fmt.Errorf("Map key is defined to be a decimal type (%v) but got error %v", keyType.Kind(), err)
}
keyVal = reflect.ValueOf(parsed)
break
}
fallthrough
default:
return keyVal, fmt.Errorf("unsupported key type: %v", keyType)
}
}
return keyVal, err
}