diff --git a/vendor/github.com/mongodb/mongo-go-driver/bson/bsoncodec/pointer_codec.go b/vendor/github.com/mongodb/mongo-go-driver/bson/bsoncodec/pointer_codec.go
new file mode 100644
index 0000000..b78ec0a
--- /dev/null
+++ b/vendor/github.com/mongodb/mongo-go-driver/bson/bsoncodec/pointer_codec.go
@@ -0,0 +1,110 @@
+// 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"
+
+	"github.com/mongodb/mongo-go-driver/bson/bsonrw"
+	"github.com/mongodb/mongo-go-driver/bson/bsontype"
+)
+
+var defaultPointerCodec = &PointerCodec{
+	ecache: make(map[reflect.Type]ValueEncoder),
+	dcache: make(map[reflect.Type]ValueDecoder),
+}
+
+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 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())
+}