110 lines
2.8 KiB
Go
110 lines
2.8 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 (
|
||
|
|
"reflect"
|
||
|
|
"sync"
|
||
|
|
|
||
|
|
"go.mongodb.org/mongo-driver/bson/bsonrw"
|
||
|
|
"go.mongodb.org/mongo-driver/bson/bsontype"
|
||
|
|
)
|
||
|
|
|
||
|
|
var _ ValueEncoder = &PointerCodec{}
|
||
|
|
var _ ValueDecoder = &PointerCodec{}
|
||
|
|
|
||
|
|
// PointerCodec is the Codec used for pointers.
|
||
|
|
type PointerCodec struct {
|
||
|
|
ecache map[reflect.Type]ValueEncoder
|
||
|
|
dcache map[reflect.Type]ValueDecoder
|
||
|
|
l sync.RWMutex
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewPointerCodec returns a PointerCodec that has been initialized.
|
||
|
|
func NewPointerCodec() *PointerCodec {
|
||
|
|
return &PointerCodec{
|
||
|
|
ecache: make(map[reflect.Type]ValueEncoder),
|
||
|
|
dcache: make(map[reflect.Type]ValueDecoder),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// EncodeValue handles encoding a pointer by either encoding it to BSON Null if the pointer is nil
|
||
|
|
// or looking up an encoder for the type of value the pointer points to.
|
||
|
|
func (pc *PointerCodec) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
|
||
|
|
if val.Kind() != reflect.Ptr {
|
||
|
|
if !val.IsValid() {
|
||
|
|
return vw.WriteNull()
|
||
|
|
}
|
||
|
|
return ValueEncoderError{Name: "PointerCodec.EncodeValue", Kinds: []reflect.Kind{reflect.Ptr}, Received: val}
|
||
|
|
}
|
||
|
|
|
||
|
|
if val.IsNil() {
|
||
|
|
return vw.WriteNull()
|
||
|
|
}
|
||
|
|
|
||
|
|
pc.l.RLock()
|
||
|
|
enc, ok := pc.ecache[val.Type()]
|
||
|
|
pc.l.RUnlock()
|
||
|
|
if ok {
|
||
|
|
if enc == nil {
|
||
|
|
return ErrNoEncoder{Type: val.Type()}
|
||
|
|
}
|
||
|
|
return enc.EncodeValue(ec, vw, val.Elem())
|
||
|
|
}
|
||
|
|
|
||
|
|
enc, err := ec.LookupEncoder(val.Type().Elem())
|
||
|
|
pc.l.Lock()
|
||
|
|
pc.ecache[val.Type()] = enc
|
||
|
|
pc.l.Unlock()
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
return enc.EncodeValue(ec, vw, val.Elem())
|
||
|
|
}
|
||
|
|
|
||
|
|
// DecodeValue handles decoding a pointer by looking up a decoder for the type it points to and
|
||
|
|
// using that to decode. If the BSON value is Null, this method will set the pointer to nil.
|
||
|
|
func (pc *PointerCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
|
||
|
|
if !val.CanSet() || val.Kind() != reflect.Ptr {
|
||
|
|
return ValueDecoderError{Name: "PointerCodec.DecodeValue", Kinds: []reflect.Kind{reflect.Ptr}, Received: val}
|
||
|
|
}
|
||
|
|
|
||
|
|
if vr.Type() == bsontype.Null {
|
||
|
|
val.Set(reflect.Zero(val.Type()))
|
||
|
|
return vr.ReadNull()
|
||
|
|
}
|
||
|
|
if vr.Type() == bsontype.Undefined {
|
||
|
|
val.Set(reflect.Zero(val.Type()))
|
||
|
|
return vr.ReadUndefined()
|
||
|
|
}
|
||
|
|
|
||
|
|
if val.IsNil() {
|
||
|
|
val.Set(reflect.New(val.Type().Elem()))
|
||
|
|
}
|
||
|
|
|
||
|
|
pc.l.RLock()
|
||
|
|
dec, ok := pc.dcache[val.Type()]
|
||
|
|
pc.l.RUnlock()
|
||
|
|
if ok {
|
||
|
|
if dec == nil {
|
||
|
|
return ErrNoDecoder{Type: val.Type()}
|
||
|
|
}
|
||
|
|
return dec.DecodeValue(dc, vr, val.Elem())
|
||
|
|
}
|
||
|
|
|
||
|
|
dec, err := dc.LookupDecoder(val.Type().Elem())
|
||
|
|
pc.l.Lock()
|
||
|
|
pc.dcache[val.Type()] = dec
|
||
|
|
pc.l.Unlock()
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
return dec.DecodeValue(dc, vr, val.Elem())
|
||
|
|
}
|