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// 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"
"go.mongodb.org/mongo-driver/bson/bsonoptions"
"go.mongodb.org/mongo-driver/bson/bsonrw"
"go.mongodb.org/mongo-driver/bson/bsontype"
"go.mongodb.org/mongo-driver/bson/primitive"
)
var defaultSliceCodec = NewSliceCodec()
// SliceCodec is the Codec used for slice values.
type SliceCodec struct {
EncodeNilAsEmpty bool
}
var _ ValueCodec = &MapCodec{}
// NewSliceCodec returns a MapCodec with options opts.
func NewSliceCodec(opts ...*bsonoptions.SliceCodecOptions) *SliceCodec {
sliceOpt := bsonoptions.MergeSliceCodecOptions(opts...)
codec := SliceCodec{}
if sliceOpt.EncodeNilAsEmpty != nil {
codec.EncodeNilAsEmpty = *sliceOpt.EncodeNilAsEmpty
}
return &codec
}
// EncodeValue is the ValueEncoder for slice types.
func (sc SliceCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
if !val.IsValid() || val.Kind() != reflect.Slice {
return ValueEncoderError{Name: "SliceEncodeValue", Kinds: []reflect.Kind{reflect.Slice}, Received: val}
}
if val.IsNil() && !sc.EncodeNilAsEmpty {
return vw.WriteNull()
}
// If we have a []byte we want to treat it as a binary instead of as an array.
if val.Type().Elem() == tByte {
var byteSlice []byte
for idx := 0; idx < val.Len(); idx++ {
byteSlice = append(byteSlice, val.Index(idx).Interface().(byte))
}
return vw.WriteBinary(byteSlice)
}
// If we have a []primitive.E we want to treat it as a document instead of as an array.
if val.Type().ConvertibleTo(tD) {
d := val.Convert(tD).Interface().(primitive.D)
dw, err := vw.WriteDocument()
if err != nil {
return err
}
for _, e := range d {
err = encodeElement(ec, dw, e)
if err != nil {
return err
}
}
return dw.WriteDocumentEnd()
}
aw, err := vw.WriteArray()
if err != nil {
return err
}
elemType := val.Type().Elem()
encoder, err := ec.LookupEncoder(elemType)
if err != nil && elemType.Kind() != reflect.Interface {
return err
}
for idx := 0; idx < val.Len(); idx++ {
currEncoder, currVal, lookupErr := defaultValueEncoders.lookupElementEncoder(ec, encoder, val.Index(idx))
if lookupErr != nil && lookupErr != errInvalidValue {
return lookupErr
}
vw, err := aw.WriteArrayElement()
if err != nil {
return err
}
if lookupErr == errInvalidValue {
err = vw.WriteNull()
if err != nil {
return err
}
continue
}
err = currEncoder.EncodeValue(ec, vw, currVal)
if err != nil {
return err
}
}
return aw.WriteArrayEnd()
}
// DecodeValue is the ValueDecoder for slice types.
func (sc *SliceCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
if !val.CanSet() || val.Kind() != reflect.Slice {
return ValueDecoderError{Name: "SliceDecodeValue", Kinds: []reflect.Kind{reflect.Slice}, Received: val}
}
switch vrType := vr.Type(); vrType {
case bsontype.Array:
case bsontype.Null:
val.Set(reflect.Zero(val.Type()))
return vr.ReadNull()
case bsontype.Undefined:
val.Set(reflect.Zero(val.Type()))
return vr.ReadUndefined()
case bsontype.Type(0), bsontype.EmbeddedDocument:
if val.Type().Elem() != tE {
return fmt.Errorf("cannot decode document into %s", val.Type())
}
case bsontype.Binary:
if val.Type().Elem() != tByte {
return fmt.Errorf("SliceDecodeValue can only decode a binary into a byte array, got %v", vrType)
}
data, subtype, err := vr.ReadBinary()
if err != nil {
return err
}
if subtype != bsontype.BinaryGeneric && subtype != bsontype.BinaryBinaryOld {
return fmt.Errorf("SliceDecodeValue can only be used to decode subtype 0x00 or 0x02 for %s, got %v", bsontype.Binary, subtype)
}
if val.IsNil() {
val.Set(reflect.MakeSlice(val.Type(), 0, len(data)))
}
val.SetLen(0)
for _, elem := range data {
val.Set(reflect.Append(val, reflect.ValueOf(elem)))
}
return nil
case bsontype.String:
if sliceType := val.Type().Elem(); sliceType != tByte {
return fmt.Errorf("SliceDecodeValue can only decode a string into a byte array, got %v", sliceType)
}
str, err := vr.ReadString()
if err != nil {
return err
}
byteStr := []byte(str)
if val.IsNil() {
val.Set(reflect.MakeSlice(val.Type(), 0, len(byteStr)))
}
val.SetLen(0)
for _, elem := range byteStr {
val.Set(reflect.Append(val, reflect.ValueOf(elem)))
}
return nil
default:
return fmt.Errorf("cannot decode %v into a slice", vrType)
}
var elemsFunc func(DecodeContext, bsonrw.ValueReader, reflect.Value) ([]reflect.Value, error)
switch val.Type().Elem() {
case tE:
dc.Ancestor = val.Type()
elemsFunc = defaultValueDecoders.decodeD
default:
elemsFunc = defaultValueDecoders.decodeDefault
}
elems, err := elemsFunc(dc, vr, val)
if err != nil {
return err
}
if val.IsNil() {
val.Set(reflect.MakeSlice(val.Type(), 0, len(elems)))
}
val.SetLen(0)
val.Set(reflect.Append(val, elems...))
return nil
}
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