Backport: Use vendored go-swagger (#8087) (#8165)

* Use vendored go-swagger (#8087)

* Use vendored go-swagger

* vendor go-swagger

* revert un wanteed change

* remove un-needed GO111MODULE

* Update Makefile

Co-Authored-By: techknowlogick <matti@mdranta.net>

* re-generate swagger file

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

@@ -0,0 +1,163 @@
+// 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 "go.mongodb.org/mongo-driver/bson/bsoncodec"
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+)
+
+// Marshaler is an interface implemented by types that can marshal themselves
+// into a BSON document represented as bytes. The bytes returned must be a valid
+// BSON document if the error is nil.
+type Marshaler interface {
+	MarshalBSON() ([]byte, error)
+}
+
+// ValueMarshaler is an interface implemented by types that can marshal
+// themselves into a BSON value as bytes. The type must be the valid type for
+// the bytes returned. The bytes and byte type together must be valid if the
+// error is nil.
+type ValueMarshaler interface {
+	MarshalBSONValue() (bsontype.Type, []byte, error)
+}
+
+// Unmarshaler is an interface implemented by types that can unmarshal a BSON
+// document representation of themselves. The BSON bytes can be assumed to be
+// valid. UnmarshalBSON must copy the BSON bytes if it wishes to retain the data
+// after returning.
+type Unmarshaler interface {
+	UnmarshalBSON([]byte) error
+}
+
+// ValueUnmarshaler is an interface implemented by types that can unmarshal a
+// BSON value representaiton of themselves. The BSON bytes and type can be
+// assumed to be valid. UnmarshalBSONValue must copy the BSON value bytes if it
+// wishes to retain the data after returning.
+type ValueUnmarshaler interface {
+	UnmarshalBSONValue(bsontype.Type, []byte) error
+}
+
+// ValueEncoderError is an error returned from a ValueEncoder when the provided value can't be
+// encoded by the ValueEncoder.
+type ValueEncoderError struct {
+	Name     string
+	Types    []reflect.Type
+	Kinds    []reflect.Kind
+	Received reflect.Value
+}
+
+func (vee ValueEncoderError) Error() string {
+	typeKinds := make([]string, 0, len(vee.Types)+len(vee.Kinds))
+	for _, t := range vee.Types {
+		typeKinds = append(typeKinds, t.String())
+	}
+	for _, k := range vee.Kinds {
+		if k == reflect.Map {
+			typeKinds = append(typeKinds, "map[string]*")
+			continue
+		}
+		typeKinds = append(typeKinds, k.String())
+	}
+	received := vee.Received.Kind().String()
+	if vee.Received.IsValid() {
+		received = vee.Received.Type().String()
+	}
+	return fmt.Sprintf("%s can only encode valid %s, but got %s", vee.Name, strings.Join(typeKinds, ", "), received)
+}
+
+// ValueDecoderError is an error returned from a ValueDecoder when the provided value can't be
+// decoded by the ValueDecoder.
+type ValueDecoderError struct {
+	Name     string
+	Types    []reflect.Type
+	Kinds    []reflect.Kind
+	Received reflect.Value
+}
+
+func (vde ValueDecoderError) Error() string {
+	typeKinds := make([]string, 0, len(vde.Types)+len(vde.Kinds))
+	for _, t := range vde.Types {
+		typeKinds = append(typeKinds, t.String())
+	}
+	for _, k := range vde.Kinds {
+		if k == reflect.Map {
+			typeKinds = append(typeKinds, "map[string]*")
+			continue
+		}
+		typeKinds = append(typeKinds, k.String())
+	}
+	received := vde.Received.Kind().String()
+	if vde.Received.IsValid() {
+		received = vde.Received.Type().String()
+	}
+	return fmt.Sprintf("%s can only decode valid and settable %s, but got %s", vde.Name, strings.Join(typeKinds, ", "), received)
+}
+
+// EncodeContext is the contextual information required for a Codec to encode a
+// value.
+type EncodeContext struct {
+	*Registry
+	MinSize bool
+}
+
+// DecodeContext is the contextual information required for a Codec to decode a
+// value.
+type DecodeContext struct {
+	*Registry
+	Truncate bool
+	// Ancestor is the type of a containing document. This is mainly used to determine what type
+	// should be used when decoding an embedded document into an empty interface. For example, if
+	// Ancestor is a bson.M, BSON embedded document values being decoded into an empty interface
+	// will be decoded into a bson.M.
+	Ancestor reflect.Type
+}
+
+// ValueCodec is the interface that groups the methods to encode and decode
+// values.
+type ValueCodec interface {
+	ValueEncoder
+	ValueDecoder
+}
+
+// ValueEncoder is the interface implemented by types that can handle the encoding of a value.
+type ValueEncoder interface {
+	EncodeValue(EncodeContext, bsonrw.ValueWriter, reflect.Value) error
+}
+
+// ValueEncoderFunc is an adapter function that allows a function with the correct signature to be
+// used as a ValueEncoder.
+type ValueEncoderFunc func(EncodeContext, bsonrw.ValueWriter, reflect.Value) error
+
+// EncodeValue implements the ValueEncoder interface.
+func (fn ValueEncoderFunc) EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	return fn(ec, vw, val)
+}
+
+// ValueDecoder is the interface implemented by types that can handle the decoding of a value.
+type ValueDecoder interface {
+	DecodeValue(DecodeContext, bsonrw.ValueReader, reflect.Value) error
+}
+
+// ValueDecoderFunc is an adapter function that allows a function with the correct signature to be
+// used as a ValueDecoder.
+type ValueDecoderFunc func(DecodeContext, bsonrw.ValueReader, reflect.Value) error
+
+// DecodeValue implements the ValueDecoder interface.
+func (fn ValueDecoderFunc) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
+	return fn(dc, vr, val)
+}
+
+// CodecZeroer is the interface implemented by Codecs that can also determine if
+// a value of the type that would be encoded is zero.
+type CodecZeroer interface {
+	IsTypeZero(interface{}) bool
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/default_value_encoders.go

@@ -0,0 +1,648 @@
+// 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 (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"math"
+	"net/url"
+	"reflect"
+	"sync"
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
+)
+
+var defaultValueEncoders DefaultValueEncoders
+
+var bvwPool = bsonrw.NewBSONValueWriterPool()
+
+var sliceWriterPool = sync.Pool{
+	New: func() interface{} {
+		sw := make(bsonrw.SliceWriter, 0, 0)
+		return &sw
+	},
+}
+
+func encodeElement(ec EncodeContext, dw bsonrw.DocumentWriter, e primitive.E) error {
+	vw, err := dw.WriteDocumentElement(e.Key)
+	if err != nil {
+		return err
+	}
+
+	if e.Value == nil {
+		return vw.WriteNull()
+	}
+	encoder, err := ec.LookupEncoder(reflect.TypeOf(e.Value))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeValue(ec, vw, reflect.ValueOf(e.Value))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// DefaultValueEncoders is a namespace type for the default ValueEncoders used
+// when creating a registry.
+type DefaultValueEncoders struct{}
+
+// RegisterDefaultEncoders will register the encoder methods attached to DefaultValueEncoders with
+// the provided RegistryBuilder.
+func (dve DefaultValueEncoders) RegisterDefaultEncoders(rb *RegistryBuilder) {
+	if rb == nil {
+		panic(errors.New("argument to RegisterDefaultEncoders must not be nil"))
+	}
+	rb.
+		RegisterEncoder(tByteSlice, ValueEncoderFunc(dve.ByteSliceEncodeValue)).
+		RegisterEncoder(tTime, ValueEncoderFunc(dve.TimeEncodeValue)).
+		RegisterEncoder(tEmpty, ValueEncoderFunc(dve.EmptyInterfaceEncodeValue)).
+		RegisterEncoder(tOID, ValueEncoderFunc(dve.ObjectIDEncodeValue)).
+		RegisterEncoder(tDecimal, ValueEncoderFunc(dve.Decimal128EncodeValue)).
+		RegisterEncoder(tJSONNumber, ValueEncoderFunc(dve.JSONNumberEncodeValue)).
+		RegisterEncoder(tURL, ValueEncoderFunc(dve.URLEncodeValue)).
+		RegisterEncoder(tValueMarshaler, ValueEncoderFunc(dve.ValueMarshalerEncodeValue)).
+		RegisterEncoder(tMarshaler, ValueEncoderFunc(dve.MarshalerEncodeValue)).
+		RegisterEncoder(tProxy, ValueEncoderFunc(dve.ProxyEncodeValue)).
+		RegisterEncoder(tJavaScript, ValueEncoderFunc(dve.JavaScriptEncodeValue)).
+		RegisterEncoder(tSymbol, ValueEncoderFunc(dve.SymbolEncodeValue)).
+		RegisterEncoder(tBinary, ValueEncoderFunc(dve.BinaryEncodeValue)).
+		RegisterEncoder(tUndefined, ValueEncoderFunc(dve.UndefinedEncodeValue)).
+		RegisterEncoder(tDateTime, ValueEncoderFunc(dve.DateTimeEncodeValue)).
+		RegisterEncoder(tNull, ValueEncoderFunc(dve.NullEncodeValue)).
+		RegisterEncoder(tRegex, ValueEncoderFunc(dve.RegexEncodeValue)).
+		RegisterEncoder(tDBPointer, ValueEncoderFunc(dve.DBPointerEncodeValue)).
+		RegisterEncoder(tTimestamp, ValueEncoderFunc(dve.TimestampEncodeValue)).
+		RegisterEncoder(tMinKey, ValueEncoderFunc(dve.MinKeyEncodeValue)).
+		RegisterEncoder(tMaxKey, ValueEncoderFunc(dve.MaxKeyEncodeValue)).
+		RegisterEncoder(tCoreDocument, ValueEncoderFunc(dve.CoreDocumentEncodeValue)).
+		RegisterEncoder(tCodeWithScope, ValueEncoderFunc(dve.CodeWithScopeEncodeValue)).
+		RegisterDefaultEncoder(reflect.Bool, ValueEncoderFunc(dve.BooleanEncodeValue)).
+		RegisterDefaultEncoder(reflect.Int, ValueEncoderFunc(dve.IntEncodeValue)).
+		RegisterDefaultEncoder(reflect.Int8, ValueEncoderFunc(dve.IntEncodeValue)).
+		RegisterDefaultEncoder(reflect.Int16, ValueEncoderFunc(dve.IntEncodeValue)).
+		RegisterDefaultEncoder(reflect.Int32, ValueEncoderFunc(dve.IntEncodeValue)).
+		RegisterDefaultEncoder(reflect.Int64, ValueEncoderFunc(dve.IntEncodeValue)).
+		RegisterDefaultEncoder(reflect.Uint, ValueEncoderFunc(dve.UintEncodeValue)).
+		RegisterDefaultEncoder(reflect.Uint8, ValueEncoderFunc(dve.UintEncodeValue)).
+		RegisterDefaultEncoder(reflect.Uint16, ValueEncoderFunc(dve.UintEncodeValue)).
+		RegisterDefaultEncoder(reflect.Uint32, ValueEncoderFunc(dve.UintEncodeValue)).
+		RegisterDefaultEncoder(reflect.Uint64, ValueEncoderFunc(dve.UintEncodeValue)).
+		RegisterDefaultEncoder(reflect.Float32, ValueEncoderFunc(dve.FloatEncodeValue)).
+		RegisterDefaultEncoder(reflect.Float64, ValueEncoderFunc(dve.FloatEncodeValue)).
+		RegisterDefaultEncoder(reflect.Array, ValueEncoderFunc(dve.ArrayEncodeValue)).
+		RegisterDefaultEncoder(reflect.Map, ValueEncoderFunc(dve.MapEncodeValue)).
+		RegisterDefaultEncoder(reflect.Slice, ValueEncoderFunc(dve.SliceEncodeValue)).
+		RegisterDefaultEncoder(reflect.String, ValueEncoderFunc(dve.StringEncodeValue)).
+		RegisterDefaultEncoder(reflect.Struct, &StructCodec{cache: make(map[reflect.Type]*structDescription), parser: DefaultStructTagParser}).
+		RegisterDefaultEncoder(reflect.Ptr, NewPointerCodec())
+}
+
+// BooleanEncodeValue is the ValueEncoderFunc for bool types.
+func (dve DefaultValueEncoders) BooleanEncodeValue(ectx EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Kind() != reflect.Bool {
+		return ValueEncoderError{Name: "BooleanEncodeValue", Kinds: []reflect.Kind{reflect.Bool}, Received: val}
+	}
+	return vw.WriteBoolean(val.Bool())
+}
+
+func fitsIn32Bits(i int64) bool {
+	return math.MinInt32 <= i && i <= math.MaxInt32
+}
+
+// IntEncodeValue is the ValueEncoderFunc for int types.
+func (dve DefaultValueEncoders) IntEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	switch val.Kind() {
+	case reflect.Int8, reflect.Int16, reflect.Int32:
+		return vw.WriteInt32(int32(val.Int()))
+	case reflect.Int:
+		i64 := val.Int()
+		if fitsIn32Bits(i64) {
+			return vw.WriteInt32(int32(i64))
+		}
+		return vw.WriteInt64(i64)
+	case reflect.Int64:
+		i64 := val.Int()
+		if ec.MinSize && fitsIn32Bits(i64) {
+			return vw.WriteInt32(int32(i64))
+		}
+		return vw.WriteInt64(i64)
+	}
+
+	return ValueEncoderError{
+		Name:     "IntEncodeValue",
+		Kinds:    []reflect.Kind{reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int},
+		Received: val,
+	}
+}
+
+// UintEncodeValue is the ValueEncoderFunc for uint types.
+func (dve DefaultValueEncoders) UintEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	switch val.Kind() {
+	case reflect.Uint8, reflect.Uint16:
+		return vw.WriteInt32(int32(val.Uint()))
+	case reflect.Uint, reflect.Uint32, reflect.Uint64:
+		u64 := val.Uint()
+		if ec.MinSize && u64 <= math.MaxInt32 {
+			return vw.WriteInt32(int32(u64))
+		}
+		if u64 > math.MaxInt64 {
+			return fmt.Errorf("%d overflows int64", u64)
+		}
+		return vw.WriteInt64(int64(u64))
+	}
+
+	return ValueEncoderError{
+		Name:     "UintEncodeValue",
+		Kinds:    []reflect.Kind{reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint},
+		Received: val,
+	}
+}
+
+// FloatEncodeValue is the ValueEncoderFunc for float types.
+func (dve DefaultValueEncoders) FloatEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	switch val.Kind() {
+	case reflect.Float32, reflect.Float64:
+		return vw.WriteDouble(val.Float())
+	}
+
+	return ValueEncoderError{Name: "FloatEncodeValue", Kinds: []reflect.Kind{reflect.Float32, reflect.Float64}, Received: val}
+}
+
+// StringEncodeValue is the ValueEncoderFunc for string types.
+func (dve DefaultValueEncoders) StringEncodeValue(ectx EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if val.Kind() != reflect.String {
+		return ValueEncoderError{
+			Name:     "StringEncodeValue",
+			Kinds:    []reflect.Kind{reflect.String},
+			Received: val,
+		}
+	}
+
+	return vw.WriteString(val.String())
+}
+
+// ObjectIDEncodeValue is the ValueEncoderFunc for primitive.ObjectID.
+func (dve DefaultValueEncoders) ObjectIDEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tOID {
+		return ValueEncoderError{Name: "ObjectIDEncodeValue", Types: []reflect.Type{tOID}, Received: val}
+	}
+	return vw.WriteObjectID(val.Interface().(primitive.ObjectID))
+}
+
+// Decimal128EncodeValue is the ValueEncoderFunc for primitive.Decimal128.
+func (dve DefaultValueEncoders) Decimal128EncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tDecimal {
+		return ValueEncoderError{Name: "Decimal128EncodeValue", Types: []reflect.Type{tDecimal}, Received: val}
+	}
+	return vw.WriteDecimal128(val.Interface().(primitive.Decimal128))
+}
+
+// JSONNumberEncodeValue is the ValueEncoderFunc for json.Number.
+func (dve DefaultValueEncoders) JSONNumberEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tJSONNumber {
+		return ValueEncoderError{Name: "JSONNumberEncodeValue", Types: []reflect.Type{tJSONNumber}, Received: val}
+	}
+	jsnum := val.Interface().(json.Number)
+
+	// Attempt int first, then float64
+	if i64, err := jsnum.Int64(); err == nil {
+		return dve.IntEncodeValue(ec, vw, reflect.ValueOf(i64))
+	}
+
+	f64, err := jsnum.Float64()
+	if err != nil {
+		return err
+	}
+
+	return dve.FloatEncodeValue(ec, vw, reflect.ValueOf(f64))
+}
+
+// URLEncodeValue is the ValueEncoderFunc for url.URL.
+func (dve DefaultValueEncoders) URLEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tURL {
+		return ValueEncoderError{Name: "URLEncodeValue", Types: []reflect.Type{tURL}, Received: val}
+	}
+	u := val.Interface().(url.URL)
+	return vw.WriteString(u.String())
+}
+
+// TimeEncodeValue is the ValueEncoderFunc for time.TIme.
+func (dve DefaultValueEncoders) TimeEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tTime {
+		return ValueEncoderError{Name: "TimeEncodeValue", Types: []reflect.Type{tTime}, Received: val}
+	}
+	tt := val.Interface().(time.Time)
+	return vw.WriteDateTime(tt.Unix()*1000 + int64(tt.Nanosecond()/1e6))
+}
+
+// ByteSliceEncodeValue is the ValueEncoderFunc for []byte.
+func (dve DefaultValueEncoders) ByteSliceEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tByteSlice {
+		return ValueEncoderError{Name: "ByteSliceEncodeValue", Types: []reflect.Type{tByteSlice}, Received: val}
+	}
+	if val.IsNil() {
+		return vw.WriteNull()
+	}
+	return vw.WriteBinary(val.Interface().([]byte))
+}
+
+// MapEncodeValue is the ValueEncoderFunc for map[string]* types.
+func (dve DefaultValueEncoders) MapEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Kind() != reflect.Map || val.Type().Key().Kind() != reflect.String {
+		return ValueEncoderError{Name: "MapEncodeValue", Kinds: []reflect.Kind{reflect.Map}, Received: val}
+	}
+
+	if val.IsNil() {
+		// If we have a nill 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 dve.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 (dve DefaultValueEncoders) mapEncodeValue(ec EncodeContext, dw bsonrw.DocumentWriter, val reflect.Value, collisionFn func(string) bool) error {
+
+	encoder, err := ec.LookupEncoder(val.Type().Elem())
+	if err != nil {
+		return err
+	}
+
+	keys := val.MapKeys()
+	for _, key := range keys {
+		if collisionFn != nil && collisionFn(key.String()) {
+			return fmt.Errorf("Key %s of inlined map conflicts with a struct field name", key)
+		}
+		vw, err := dw.WriteDocumentElement(key.String())
+		if err != nil {
+			return err
+		}
+
+		if enc, ok := encoder.(ValueEncoder); ok {
+			err = enc.EncodeValue(ec, vw, val.MapIndex(key))
+			if err != nil {
+				return err
+			}
+			continue
+		}
+		err = encoder.EncodeValue(ec, vw, val.MapIndex(key))
+		if err != nil {
+			return err
+		}
+	}
+
+	return dw.WriteDocumentEnd()
+}
+
+// ArrayEncodeValue is the ValueEncoderFunc for array types.
+func (dve DefaultValueEncoders) ArrayEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Kind() != reflect.Array {
+		return ValueEncoderError{Name: "ArrayEncodeValue", Kinds: []reflect.Kind{reflect.Array}, Received: val}
+	}
+
+	// If we have a []primitive.E we want to treat it as a document instead of as an array.
+	if val.Type().Elem() == tE {
+		dw, err := vw.WriteDocument()
+		if err != nil {
+			return err
+		}
+
+		for idx := 0; idx < val.Len(); idx++ {
+			e := val.Index(idx).Interface().(primitive.E)
+			err = encodeElement(ec, dw, e)
+			if err != nil {
+				return err
+			}
+		}
+
+		return dw.WriteDocumentEnd()
+	}
+
+	aw, err := vw.WriteArray()
+	if err != nil {
+		return err
+	}
+
+	encoder, err := ec.LookupEncoder(val.Type().Elem())
+	if err != nil {
+		return err
+	}
+
+	for idx := 0; idx < val.Len(); idx++ {
+		vw, err := aw.WriteArrayElement()
+		if err != nil {
+			return err
+		}
+
+		err = encoder.EncodeValue(ec, vw, val.Index(idx))
+		if err != nil {
+			return err
+		}
+	}
+	return aw.WriteArrayEnd()
+}
+
+// SliceEncodeValue is the ValueEncoderFunc for slice types.
+func (dve DefaultValueEncoders) SliceEncodeValue(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() {
+		return vw.WriteNull()
+	}
+
+	// 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
+	}
+
+	encoder, err := ec.LookupEncoder(val.Type().Elem())
+	if err != nil {
+		return err
+	}
+
+	for idx := 0; idx < val.Len(); idx++ {
+		vw, err := aw.WriteArrayElement()
+		if err != nil {
+			return err
+		}
+
+		err = encoder.EncodeValue(ec, vw, val.Index(idx))
+		if err != nil {
+			return err
+		}
+	}
+	return aw.WriteArrayEnd()
+}
+
+// EmptyInterfaceEncodeValue is the ValueEncoderFunc for interface{}.
+func (dve DefaultValueEncoders) EmptyInterfaceEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tEmpty {
+		return ValueEncoderError{Name: "EmptyInterfaceEncodeValue", Types: []reflect.Type{tEmpty}, Received: val}
+	}
+
+	if val.IsNil() {
+		return vw.WriteNull()
+	}
+	encoder, err := ec.LookupEncoder(val.Elem().Type())
+	if err != nil {
+		return err
+	}
+
+	return encoder.EncodeValue(ec, vw, val.Elem())
+}
+
+// ValueMarshalerEncodeValue is the ValueEncoderFunc for ValueMarshaler implementations.
+func (dve DefaultValueEncoders) ValueMarshalerEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || !val.Type().Implements(tValueMarshaler) {
+		return ValueEncoderError{Name: "ValueMarshalerEncodeValue", Types: []reflect.Type{tValueMarshaler}, Received: val}
+	}
+
+	fn := val.Convert(tValueMarshaler).MethodByName("MarshalBSONValue")
+	returns := fn.Call(nil)
+	if !returns[2].IsNil() {
+		return returns[2].Interface().(error)
+	}
+	t, data := returns[0].Interface().(bsontype.Type), returns[1].Interface().([]byte)
+	return bsonrw.Copier{}.CopyValueFromBytes(vw, t, data)
+}
+
+// MarshalerEncodeValue is the ValueEncoderFunc for Marshaler implementations.
+func (dve DefaultValueEncoders) MarshalerEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || !val.Type().Implements(tMarshaler) {
+		return ValueEncoderError{Name: "MarshalerEncodeValue", Types: []reflect.Type{tMarshaler}, Received: val}
+	}
+
+	fn := val.Convert(tMarshaler).MethodByName("MarshalBSON")
+	returns := fn.Call(nil)
+	if !returns[1].IsNil() {
+		return returns[1].Interface().(error)
+	}
+	data := returns[0].Interface().([]byte)
+	return bsonrw.Copier{}.CopyValueFromBytes(vw, bsontype.EmbeddedDocument, data)
+}
+
+// ProxyEncodeValue is the ValueEncoderFunc for Proxy implementations.
+func (dve DefaultValueEncoders) ProxyEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || !val.Type().Implements(tProxy) {
+		return ValueEncoderError{Name: "ProxyEncodeValue", Types: []reflect.Type{tProxy}, Received: val}
+	}
+
+	fn := val.Convert(tProxy).MethodByName("ProxyBSON")
+	returns := fn.Call(nil)
+	if !returns[1].IsNil() {
+		return returns[1].Interface().(error)
+	}
+	data := returns[0]
+	var encoder ValueEncoder
+	var err error
+	if data.Elem().IsValid() {
+		encoder, err = ec.LookupEncoder(data.Elem().Type())
+	} else {
+		encoder, err = ec.LookupEncoder(nil)
+	}
+	if err != nil {
+		return err
+	}
+	return encoder.EncodeValue(ec, vw, data.Elem())
+}
+
+// JavaScriptEncodeValue is the ValueEncoderFunc for the primitive.JavaScript type.
+func (DefaultValueEncoders) JavaScriptEncodeValue(ectx EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tJavaScript {
+		return ValueEncoderError{Name: "JavaScriptEncodeValue", Types: []reflect.Type{tJavaScript}, Received: val}
+	}
+
+	return vw.WriteJavascript(val.String())
+}
+
+// SymbolEncodeValue is the ValueEncoderFunc for the primitive.Symbol type.
+func (DefaultValueEncoders) SymbolEncodeValue(ectx EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tSymbol {
+		return ValueEncoderError{Name: "SymbolEncodeValue", Types: []reflect.Type{tSymbol}, Received: val}
+	}
+
+	return vw.WriteSymbol(val.String())
+}
+
+// BinaryEncodeValue is the ValueEncoderFunc for Binary.
+func (DefaultValueEncoders) BinaryEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tBinary {
+		return ValueEncoderError{Name: "BinaryEncodeValue", Types: []reflect.Type{tBinary}, Received: val}
+	}
+	b := val.Interface().(primitive.Binary)
+
+	return vw.WriteBinaryWithSubtype(b.Data, b.Subtype)
+}
+
+// UndefinedEncodeValue is the ValueEncoderFunc for Undefined.
+func (DefaultValueEncoders) UndefinedEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tUndefined {
+		return ValueEncoderError{Name: "UndefinedEncodeValue", Types: []reflect.Type{tUndefined}, Received: val}
+	}
+
+	return vw.WriteUndefined()
+}
+
+// DateTimeEncodeValue is the ValueEncoderFunc for DateTime.
+func (DefaultValueEncoders) DateTimeEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tDateTime {
+		return ValueEncoderError{Name: "DateTimeEncodeValue", Types: []reflect.Type{tDateTime}, Received: val}
+	}
+
+	return vw.WriteDateTime(val.Int())
+}
+
+// NullEncodeValue is the ValueEncoderFunc for Null.
+func (DefaultValueEncoders) NullEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tNull {
+		return ValueEncoderError{Name: "NullEncodeValue", Types: []reflect.Type{tNull}, Received: val}
+	}
+
+	return vw.WriteNull()
+}
+
+// RegexEncodeValue is the ValueEncoderFunc for Regex.
+func (DefaultValueEncoders) RegexEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tRegex {
+		return ValueEncoderError{Name: "RegexEncodeValue", Types: []reflect.Type{tRegex}, Received: val}
+	}
+
+	regex := val.Interface().(primitive.Regex)
+
+	return vw.WriteRegex(regex.Pattern, regex.Options)
+}
+
+// DBPointerEncodeValue is the ValueEncoderFunc for DBPointer.
+func (DefaultValueEncoders) DBPointerEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tDBPointer {
+		return ValueEncoderError{Name: "DBPointerEncodeValue", Types: []reflect.Type{tDBPointer}, Received: val}
+	}
+
+	dbp := val.Interface().(primitive.DBPointer)
+
+	return vw.WriteDBPointer(dbp.DB, dbp.Pointer)
+}
+
+// TimestampEncodeValue is the ValueEncoderFunc for Timestamp.
+func (DefaultValueEncoders) TimestampEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tTimestamp {
+		return ValueEncoderError{Name: "TimestampEncodeValue", Types: []reflect.Type{tTimestamp}, Received: val}
+	}
+
+	ts := val.Interface().(primitive.Timestamp)
+
+	return vw.WriteTimestamp(ts.T, ts.I)
+}
+
+// MinKeyEncodeValue is the ValueEncoderFunc for MinKey.
+func (DefaultValueEncoders) MinKeyEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tMinKey {
+		return ValueEncoderError{Name: "MinKeyEncodeValue", Types: []reflect.Type{tMinKey}, Received: val}
+	}
+
+	return vw.WriteMinKey()
+}
+
+// MaxKeyEncodeValue is the ValueEncoderFunc for MaxKey.
+func (DefaultValueEncoders) MaxKeyEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tMaxKey {
+		return ValueEncoderError{Name: "MaxKeyEncodeValue", Types: []reflect.Type{tMaxKey}, Received: val}
+	}
+
+	return vw.WriteMaxKey()
+}
+
+// CoreDocumentEncodeValue is the ValueEncoderFunc for bsoncore.Document.
+func (DefaultValueEncoders) CoreDocumentEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tCoreDocument {
+		return ValueEncoderError{Name: "CoreDocumentEncodeValue", Types: []reflect.Type{tCoreDocument}, Received: val}
+	}
+
+	cdoc := val.Interface().(bsoncore.Document)
+
+	return bsonrw.Copier{}.CopyDocumentFromBytes(vw, cdoc)
+}
+
+// CodeWithScopeEncodeValue is the ValueEncoderFunc for CodeWithScope.
+func (dve DefaultValueEncoders) CodeWithScopeEncodeValue(ec EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Type() != tCodeWithScope {
+		return ValueEncoderError{Name: "CodeWithScopeEncodeValue", Types: []reflect.Type{tCodeWithScope}, Received: val}
+	}
+
+	cws := val.Interface().(primitive.CodeWithScope)
+
+	dw, err := vw.WriteCodeWithScope(string(cws.Code))
+	if err != nil {
+		return err
+	}
+
+	sw := sliceWriterPool.Get().(*bsonrw.SliceWriter)
+	defer sliceWriterPool.Put(sw)
+	*sw = (*sw)[:0]
+
+	scopeVW := bvwPool.Get(sw)
+	defer bvwPool.Put(scopeVW)
+
+	encoder, err := ec.LookupEncoder(reflect.TypeOf(cws.Scope))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeValue(ec, scopeVW, reflect.ValueOf(cws.Scope))
+	if err != nil {
+		return err
+	}
+
+	err = bsonrw.Copier{}.CopyBytesToDocumentWriter(dw, *sw)
+	if err != nil {
+		return err
+	}
+	return dw.WriteDocumentEnd()
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/doc.go

@@ -0,0 +1,61 @@
+// Package bsoncodec provides a system for encoding values to BSON representations and decoding
+// values from BSON representations. This package considers both binary BSON and ExtendedJSON as
+// BSON representations. The types in this package enable a flexible system for handling this
+// encoding and decoding.
+//
+// The codec system is composed of two parts:
+//
+// 1) ValueEncoders and ValueDecoders that handle encoding and decoding Go values to and from BSON
+// representations.
+//
+// 2) A Registry that holds these ValueEncoders and ValueDecoders and provides methods for
+// retrieving them.
+//
+// ValueEncoders and ValueDecoders
+//
+// The ValueEncoder interface is implemented by types that can encode a provided Go type to BSON.
+// The value to encode is provided as a reflect.Value and a bsonrw.ValueWriter is used within the
+// EncodeValue method to actually create the BSON representation. For convenience, ValueEncoderFunc
+// is provided to allow use of a function with the correct signature as a ValueEncoder. An
+// EncodeContext instance is provided to allow implementations to lookup further ValueEncoders and
+// to provide configuration information.
+//
+// The ValueDecoder interface is the inverse of the ValueEncoder. Implementations should ensure that
+// the value they receive is settable. Similar to ValueEncoderFunc, ValueDecoderFunc is provided to
+// allow the use of a function with the correct signature as a ValueDecoder. A DecodeContext
+// instance is provided and serves similar functionality to the EncodeContext.
+//
+// Registry and RegistryBuilder
+//
+// A Registry is an immutable store for ValueEncoders, ValueDecoders, and a type map. For looking up
+// ValueEncoders and Decoders the Registry first attempts to find a ValueEncoder or ValueDecoder for
+// the type provided; if one cannot be found it then checks to see if a registered ValueEncoder or
+// ValueDecoder exists for an interface the type implements. Finally, the reflect.Kind of the type
+// is used to lookup a default ValueEncoder or ValueDecoder for that kind. If no ValueEncoder or
+// ValueDecoder can be found, an error is returned.
+//
+// The Registry also holds a type map. This allows users to retrieve the Go type that should be used
+// when decoding a BSON value into an empty interface. This is primarily only used for the empty
+// interface ValueDecoder.
+//
+// A RegistryBuilder is used to construct a Registry. The Register methods are used to associate
+// either a reflect.Type or a reflect.Kind with a ValueEncoder or ValueDecoder. A RegistryBuilder
+// returned from NewRegistryBuilder contains no registered ValueEncoders nor ValueDecoders and
+// contains an empty type map.
+//
+// The RegisterTypeMapEntry method handles associating a BSON type with a Go type. For example, if
+// you want to decode BSON int64 and int32 values into Go int instances, you would do the following:
+//
+//  var regbuilder *RegistryBuilder = ... intType := reflect.TypeOf(int(0))
+//  regbuilder.RegisterTypeMapEntry(bsontype.Int64, intType).RegisterTypeMapEntry(bsontype.Int32,
+//  intType)
+//
+// DefaultValueEncoders and DefaultValueDecoders
+//
+// The DefaultValueEncoders and DefaultValueDecoders types provide a full set of ValueEncoders and
+// ValueDecoders for handling a wide range of Go types, including all of the types within the
+// primitive package. To make registering these codecs easier, a helper method on each type is
+// provided. For the DefaultValueEncoders type the method is called RegisterDefaultEncoders and for
+// the DefaultValueDecoders type the method is called RegisterDefaultDecoders, this method also
+// handles registering type map entries for each BSON type.
+package bsoncodec

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/mode.go

@@ -0,0 +1,65 @@
+// 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"
+
+type mode int
+
+const (
+	_ mode = iota
+	mTopLevel
+	mDocument
+	mArray
+	mValue
+	mElement
+	mCodeWithScope
+	mSpacer
+)
+
+func (m mode) String() string {
+	var str string
+
+	switch m {
+	case mTopLevel:
+		str = "TopLevel"
+	case mDocument:
+		str = "DocumentMode"
+	case mArray:
+		str = "ArrayMode"
+	case mValue:
+		str = "ValueMode"
+	case mElement:
+		str = "ElementMode"
+	case mCodeWithScope:
+		str = "CodeWithScopeMode"
+	case mSpacer:
+		str = "CodeWithScopeSpacerFrame"
+	default:
+		str = "UnknownMode"
+	}
+
+	return str
+}
+
+// TransitionError is an error returned when an invalid progressing a
+// ValueReader or ValueWriter state machine occurs.
+type TransitionError struct {
+	parent      mode
+	current     mode
+	destination mode
+}
+
+func (te TransitionError) Error() string {
+	if te.destination == mode(0) {
+		return fmt.Sprintf("invalid state transition: cannot read/write value while in %s", te.current)
+	}
+	if te.parent == mode(0) {
+		return fmt.Sprintf("invalid state transition: %s -> %s", te.current, te.destination)
+	}
+	return fmt.Sprintf("invalid state transition: %s -> %s; parent %s", te.current, te.destination, te.parent)
+}

vendor/go.mongodb.org/mongo-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"
+
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
+	"go.mongodb.org/mongo-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())
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/proxy.go

@@ -0,0 +1,14 @@
+// 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
+
+// Proxy is an interface implemented by types that cannot themselves be directly encoded. Types
+// that implement this interface with have ProxyBSON called during the encoding process and that
+// value will be encoded in place for the implementer.
+type Proxy interface {
+	ProxyBSON() (interface{}, error)
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/registry.go

@@ -0,0 +1,384 @@
+// 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 (
+	"errors"
+	"reflect"
+	"sync"
+
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+)
+
+// ErrNilType is returned when nil is passed to either LookupEncoder or LookupDecoder.
+var ErrNilType = errors.New("cannot perform a decoder lookup on <nil>")
+
+// ErrNotPointer is returned when a non-pointer type is provided to LookupDecoder.
+var ErrNotPointer = errors.New("non-pointer provided to LookupDecoder")
+
+// ErrNoEncoder is returned when there wasn't an encoder available for a type.
+type ErrNoEncoder struct {
+	Type reflect.Type
+}
+
+func (ene ErrNoEncoder) Error() string {
+	if ene.Type == nil {
+		return "no encoder found for <nil>"
+	}
+	return "no encoder found for " + ene.Type.String()
+}
+
+// ErrNoDecoder is returned when there wasn't a decoder available for a type.
+type ErrNoDecoder struct {
+	Type reflect.Type
+}
+
+func (end ErrNoDecoder) Error() string {
+	return "no decoder found for " + end.Type.String()
+}
+
+// ErrNoTypeMapEntry is returned when there wasn't a type available for the provided BSON type.
+type ErrNoTypeMapEntry struct {
+	Type bsontype.Type
+}
+
+func (entme ErrNoTypeMapEntry) Error() string {
+	return "no type map entry found for " + entme.Type.String()
+}
+
+// ErrNotInterface is returned when the provided type is not an interface.
+var ErrNotInterface = errors.New("The provided type is not an interface")
+
+var defaultRegistry *Registry
+
+func init() {
+	defaultRegistry = buildDefaultRegistry()
+}
+
+// A RegistryBuilder is used to build a Registry. This type is not goroutine
+// safe.
+type RegistryBuilder struct {
+	typeEncoders      map[reflect.Type]ValueEncoder
+	interfaceEncoders []interfaceValueEncoder
+	kindEncoders      map[reflect.Kind]ValueEncoder
+
+	typeDecoders      map[reflect.Type]ValueDecoder
+	interfaceDecoders []interfaceValueDecoder
+	kindDecoders      map[reflect.Kind]ValueDecoder
+
+	typeMap map[bsontype.Type]reflect.Type
+}
+
+// A Registry is used to store and retrieve codecs for types and interfaces. This type is the main
+// typed passed around and Encoders and Decoders are constructed from it.
+type Registry struct {
+	typeEncoders map[reflect.Type]ValueEncoder
+	typeDecoders map[reflect.Type]ValueDecoder
+
+	interfaceEncoders []interfaceValueEncoder
+	interfaceDecoders []interfaceValueDecoder
+
+	kindEncoders map[reflect.Kind]ValueEncoder
+	kindDecoders map[reflect.Kind]ValueDecoder
+
+	typeMap map[bsontype.Type]reflect.Type
+
+	mu sync.RWMutex
+}
+
+// NewRegistryBuilder creates a new empty RegistryBuilder.
+func NewRegistryBuilder() *RegistryBuilder {
+	return &RegistryBuilder{
+		typeEncoders: make(map[reflect.Type]ValueEncoder),
+		typeDecoders: make(map[reflect.Type]ValueDecoder),
+
+		interfaceEncoders: make([]interfaceValueEncoder, 0),
+		interfaceDecoders: make([]interfaceValueDecoder, 0),
+
+		kindEncoders: make(map[reflect.Kind]ValueEncoder),
+		kindDecoders: make(map[reflect.Kind]ValueDecoder),
+
+		typeMap: make(map[bsontype.Type]reflect.Type),
+	}
+}
+
+func buildDefaultRegistry() *Registry {
+	rb := NewRegistryBuilder()
+	defaultValueEncoders.RegisterDefaultEncoders(rb)
+	defaultValueDecoders.RegisterDefaultDecoders(rb)
+	return rb.Build()
+}
+
+// RegisterCodec will register the provided ValueCodec for the provided type.
+func (rb *RegistryBuilder) RegisterCodec(t reflect.Type, codec ValueCodec) *RegistryBuilder {
+	rb.RegisterEncoder(t, codec)
+	rb.RegisterDecoder(t, codec)
+	return rb
+}
+
+// RegisterEncoder will register the provided ValueEncoder to the provided type.
+//
+// The type registered will be used directly, so an encoder can be registered for a type and a
+// different encoder can be registered for a pointer to that type.
+func (rb *RegistryBuilder) RegisterEncoder(t reflect.Type, enc ValueEncoder) *RegistryBuilder {
+	if t == tEmpty {
+		rb.typeEncoders[t] = enc
+		return rb
+	}
+	switch t.Kind() {
+	case reflect.Interface:
+		for idx, ir := range rb.interfaceEncoders {
+			if ir.i == t {
+				rb.interfaceEncoders[idx].ve = enc
+				return rb
+			}
+		}
+
+		rb.interfaceEncoders = append(rb.interfaceEncoders, interfaceValueEncoder{i: t, ve: enc})
+	default:
+		rb.typeEncoders[t] = enc
+	}
+	return rb
+}
+
+// RegisterDecoder will register the provided ValueDecoder to the provided type.
+//
+// The type registered will be used directly, so a decoder can be registered for a type and a
+// different decoder can be registered for a pointer to that type.
+func (rb *RegistryBuilder) RegisterDecoder(t reflect.Type, dec ValueDecoder) *RegistryBuilder {
+	if t == nil {
+		rb.typeDecoders[nil] = dec
+		return rb
+	}
+	if t == tEmpty {
+		rb.typeDecoders[t] = dec
+		return rb
+	}
+	switch t.Kind() {
+	case reflect.Interface:
+		for idx, ir := range rb.interfaceDecoders {
+			if ir.i == t {
+				rb.interfaceDecoders[idx].vd = dec
+				return rb
+			}
+		}
+
+		rb.interfaceDecoders = append(rb.interfaceDecoders, interfaceValueDecoder{i: t, vd: dec})
+	default:
+		rb.typeDecoders[t] = dec
+	}
+	return rb
+}
+
+// RegisterDefaultEncoder will registr the provided ValueEncoder to the provided
+// kind.
+func (rb *RegistryBuilder) RegisterDefaultEncoder(kind reflect.Kind, enc ValueEncoder) *RegistryBuilder {
+	rb.kindEncoders[kind] = enc
+	return rb
+}
+
+// RegisterDefaultDecoder will register the provided ValueDecoder to the
+// provided kind.
+func (rb *RegistryBuilder) RegisterDefaultDecoder(kind reflect.Kind, dec ValueDecoder) *RegistryBuilder {
+	rb.kindDecoders[kind] = dec
+	return rb
+}
+
+// RegisterTypeMapEntry will register the provided type to the BSON type. The primary usage for this
+// mapping is decoding situations where an empty interface is used and a default type needs to be
+// created and decoded into.
+//
+// NOTE: It is unlikely that registering a type for BSON Embedded Document is actually desired. By
+// registering a type map entry for BSON Embedded Document the type registered will be used in any
+// case where a BSON Embedded Document will be decoded into an empty interface. For example, if you
+// register primitive.M, the EmptyInterface decoder will always use primitive.M, even if an ancestor
+// was a primitive.D.
+func (rb *RegistryBuilder) RegisterTypeMapEntry(bt bsontype.Type, rt reflect.Type) *RegistryBuilder {
+	rb.typeMap[bt] = rt
+	return rb
+}
+
+// Build creates a Registry from the current state of this RegistryBuilder.
+func (rb *RegistryBuilder) Build() *Registry {
+	registry := new(Registry)
+
+	registry.typeEncoders = make(map[reflect.Type]ValueEncoder)
+	for t, enc := range rb.typeEncoders {
+		registry.typeEncoders[t] = enc
+	}
+
+	registry.typeDecoders = make(map[reflect.Type]ValueDecoder)
+	for t, dec := range rb.typeDecoders {
+		registry.typeDecoders[t] = dec
+	}
+
+	registry.interfaceEncoders = make([]interfaceValueEncoder, len(rb.interfaceEncoders))
+	copy(registry.interfaceEncoders, rb.interfaceEncoders)
+
+	registry.interfaceDecoders = make([]interfaceValueDecoder, len(rb.interfaceDecoders))
+	copy(registry.interfaceDecoders, rb.interfaceDecoders)
+
+	registry.kindEncoders = make(map[reflect.Kind]ValueEncoder)
+	for kind, enc := range rb.kindEncoders {
+		registry.kindEncoders[kind] = enc
+	}
+
+	registry.kindDecoders = make(map[reflect.Kind]ValueDecoder)
+	for kind, dec := range rb.kindDecoders {
+		registry.kindDecoders[kind] = dec
+	}
+
+	registry.typeMap = make(map[bsontype.Type]reflect.Type)
+	for bt, rt := range rb.typeMap {
+		registry.typeMap[bt] = rt
+	}
+
+	return registry
+}
+
+// LookupEncoder will inspect the registry for an encoder that satisfies the
+// type provided. An encoder registered for a specific type will take
+// precedence over an encoder registered for an interface the type satisfies,
+// which takes precedence over an encoder for the reflect.Kind of the value. If
+// no encoder can be found, an error is returned.
+func (r *Registry) LookupEncoder(t reflect.Type) (ValueEncoder, error) {
+	encodererr := ErrNoEncoder{Type: t}
+	r.mu.RLock()
+	enc, found := r.lookupTypeEncoder(t)
+	r.mu.RUnlock()
+	if found {
+		if enc == nil {
+			return nil, ErrNoEncoder{Type: t}
+		}
+		return enc, nil
+	}
+
+	enc, found = r.lookupInterfaceEncoder(t)
+	if found {
+		r.mu.Lock()
+		r.typeEncoders[t] = enc
+		r.mu.Unlock()
+		return enc, nil
+	}
+
+	if t == nil {
+		r.mu.Lock()
+		r.typeEncoders[t] = nil
+		r.mu.Unlock()
+		return nil, encodererr
+	}
+
+	enc, found = r.kindEncoders[t.Kind()]
+	if !found {
+		r.mu.Lock()
+		r.typeEncoders[t] = nil
+		r.mu.Unlock()
+		return nil, encodererr
+	}
+
+	r.mu.Lock()
+	r.typeEncoders[t] = enc
+	r.mu.Unlock()
+	return enc, nil
+}
+
+func (r *Registry) lookupTypeEncoder(t reflect.Type) (ValueEncoder, bool) {
+	enc, found := r.typeEncoders[t]
+	return enc, found
+}
+
+func (r *Registry) lookupInterfaceEncoder(t reflect.Type) (ValueEncoder, bool) {
+	if t == nil {
+		return nil, false
+	}
+	for _, ienc := range r.interfaceEncoders {
+		if !t.Implements(ienc.i) {
+			continue
+		}
+
+		return ienc.ve, true
+	}
+	return nil, false
+}
+
+// LookupDecoder will inspect the registry for a decoder that satisfies the
+// type provided. A decoder registered for a specific type will take
+// precedence over a decoder registered for an interface the type satisfies,
+// which takes precedence over a decoder for the reflect.Kind of the value. If
+// no decoder can be found, an error is returned.
+func (r *Registry) LookupDecoder(t reflect.Type) (ValueDecoder, error) {
+	if t == nil {
+		return nil, ErrNilType
+	}
+	decodererr := ErrNoDecoder{Type: t}
+	r.mu.RLock()
+	dec, found := r.lookupTypeDecoder(t)
+	r.mu.RUnlock()
+	if found {
+		if dec == nil {
+			return nil, ErrNoDecoder{Type: t}
+		}
+		return dec, nil
+	}
+
+	dec, found = r.lookupInterfaceDecoder(t)
+	if found {
+		r.mu.Lock()
+		r.typeDecoders[t] = dec
+		r.mu.Unlock()
+		return dec, nil
+	}
+
+	dec, found = r.kindDecoders[t.Kind()]
+	if !found {
+		r.mu.Lock()
+		r.typeDecoders[t] = nil
+		r.mu.Unlock()
+		return nil, decodererr
+	}
+
+	r.mu.Lock()
+	r.typeDecoders[t] = dec
+	r.mu.Unlock()
+	return dec, nil
+}
+
+func (r *Registry) lookupTypeDecoder(t reflect.Type) (ValueDecoder, bool) {
+	dec, found := r.typeDecoders[t]
+	return dec, found
+}
+
+func (r *Registry) lookupInterfaceDecoder(t reflect.Type) (ValueDecoder, bool) {
+	for _, idec := range r.interfaceDecoders {
+		if !t.Implements(idec.i) && !reflect.PtrTo(t).Implements(idec.i) {
+			continue
+		}
+
+		return idec.vd, true
+	}
+	return nil, false
+}
+
+// LookupTypeMapEntry inspects the registry's type map for a Go type for the corresponding BSON
+// type. If no type is found, ErrNoTypeMapEntry is returned.
+func (r *Registry) LookupTypeMapEntry(bt bsontype.Type) (reflect.Type, error) {
+	t, ok := r.typeMap[bt]
+	if !ok || t == nil {
+		return nil, ErrNoTypeMapEntry{Type: bt}
+	}
+	return t, nil
+}
+
+type interfaceValueEncoder struct {
+	i  reflect.Type
+	ve ValueEncoder
+}
+
+type interfaceValueDecoder struct {
+	i  reflect.Type
+	vd ValueDecoder
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/struct_codec.go

@@ -0,0 +1,359 @@
+// 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 (
+	"errors"
+	"fmt"
+	"reflect"
+	"sync"
+
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+)
+
+var defaultStructCodec = &StructCodec{
+	cache:  make(map[reflect.Type]*structDescription),
+	parser: DefaultStructTagParser,
+}
+
+// Zeroer allows custom struct types to implement a report of zero
+// state. All struct types that don't implement Zeroer or where IsZero
+// returns false are considered to be not zero.
+type Zeroer interface {
+	IsZero() bool
+}
+
+// StructCodec is the Codec used for struct values.
+type StructCodec struct {
+	cache  map[reflect.Type]*structDescription
+	l      sync.RWMutex
+	parser StructTagParser
+}
+
+var _ ValueEncoder = &StructCodec{}
+var _ ValueDecoder = &StructCodec{}
+
+// NewStructCodec returns a StructCodec that uses p for struct tag parsing.
+func NewStructCodec(p StructTagParser) (*StructCodec, error) {
+	if p == nil {
+		return nil, errors.New("a StructTagParser must be provided to NewStructCodec")
+	}
+
+	return &StructCodec{
+		cache:  make(map[reflect.Type]*structDescription),
+		parser: p,
+	}, nil
+}
+
+// EncodeValue handles encoding generic struct types.
+func (sc *StructCodec) EncodeValue(r EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Kind() != reflect.Struct {
+		return ValueEncoderError{Name: "StructCodec.EncodeValue", Kinds: []reflect.Kind{reflect.Struct}, Received: val}
+	}
+
+	sd, err := sc.describeStruct(r.Registry, val.Type())
+	if err != nil {
+		return err
+	}
+
+	dw, err := vw.WriteDocument()
+	if err != nil {
+		return err
+	}
+	var rv reflect.Value
+	for _, desc := range sd.fl {
+		if desc.inline == nil {
+			rv = val.Field(desc.idx)
+		} else {
+			rv = val.FieldByIndex(desc.inline)
+		}
+
+		if desc.encoder == nil {
+			return ErrNoEncoder{Type: rv.Type()}
+		}
+
+		encoder := desc.encoder
+
+		iszero := sc.isZero
+		if iz, ok := encoder.(CodecZeroer); ok {
+			iszero = iz.IsTypeZero
+		}
+
+		if desc.omitEmpty && iszero(rv.Interface()) {
+			continue
+		}
+
+		vw2, err := dw.WriteDocumentElement(desc.name)
+		if err != nil {
+			return err
+		}
+
+		ectx := EncodeContext{Registry: r.Registry, MinSize: desc.minSize}
+		err = encoder.EncodeValue(ectx, vw2, rv)
+		if err != nil {
+			return err
+		}
+	}
+
+	if sd.inlineMap >= 0 {
+		rv := val.Field(sd.inlineMap)
+		collisionFn := func(key string) bool {
+			_, exists := sd.fm[key]
+			return exists
+		}
+
+		return defaultValueEncoders.mapEncodeValue(r, dw, rv, collisionFn)
+	}
+
+	return dw.WriteDocumentEnd()
+}
+
+// DecodeValue implements the Codec interface.
+// By default, map types in val will not be cleared. If a map has existing key/value pairs, it will be extended with the new ones from vr.
+// For slices, the decoder will set the length of the slice to zero and append all elements. The underlying array will not be cleared.
+func (sc *StructCodec) DecodeValue(r DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
+	if !val.CanSet() || val.Kind() != reflect.Struct {
+		return ValueDecoderError{Name: "StructCodec.DecodeValue", Kinds: []reflect.Kind{reflect.Struct}, Received: val}
+	}
+
+	switch vr.Type() {
+	case bsontype.Type(0), bsontype.EmbeddedDocument:
+	default:
+		return fmt.Errorf("cannot decode %v into a %s", vr.Type(), val.Type())
+	}
+
+	sd, err := sc.describeStruct(r.Registry, val.Type())
+	if err != nil {
+		return err
+	}
+
+	var decoder ValueDecoder
+	var inlineMap reflect.Value
+	if sd.inlineMap >= 0 {
+		inlineMap = val.Field(sd.inlineMap)
+		if inlineMap.IsNil() {
+			inlineMap.Set(reflect.MakeMap(inlineMap.Type()))
+		}
+		decoder, err = r.LookupDecoder(inlineMap.Type().Elem())
+		if err != nil {
+			return err
+		}
+	}
+
+	dr, err := vr.ReadDocument()
+	if err != nil {
+		return err
+	}
+
+	for {
+		name, vr, err := dr.ReadElement()
+		if err == bsonrw.ErrEOD {
+			break
+		}
+		if err != nil {
+			return err
+		}
+
+		fd, exists := sd.fm[name]
+		if !exists {
+			if sd.inlineMap < 0 {
+				// The encoding/json package requires a flag to return on error for non-existent fields.
+				// This functionality seems appropriate for the struct codec.
+				err = vr.Skip()
+				if err != nil {
+					return err
+				}
+				continue
+			}
+
+			elem := reflect.New(inlineMap.Type().Elem()).Elem()
+			err = decoder.DecodeValue(r, vr, elem)
+			if err != nil {
+				return err
+			}
+			inlineMap.SetMapIndex(reflect.ValueOf(name), elem)
+			continue
+		}
+
+		var field reflect.Value
+		if fd.inline == nil {
+			field = val.Field(fd.idx)
+		} else {
+			field = val.FieldByIndex(fd.inline)
+		}
+
+		if !field.CanSet() { // Being settable is a super set of being addressable.
+			return fmt.Errorf("cannot decode element '%s' into field %v; it is not settable", name, field)
+		}
+		if field.Kind() == reflect.Ptr && field.IsNil() {
+			field.Set(reflect.New(field.Type().Elem()))
+		}
+		field = field.Addr()
+
+		dctx := DecodeContext{Registry: r.Registry, Truncate: fd.truncate}
+		if fd.decoder == nil {
+			return ErrNoDecoder{Type: field.Elem().Type()}
+		}
+
+		if decoder, ok := fd.decoder.(ValueDecoder); ok {
+			err = decoder.DecodeValue(dctx, vr, field.Elem())
+			if err != nil {
+				return err
+			}
+			continue
+		}
+		err = fd.decoder.DecodeValue(dctx, vr, field)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (sc *StructCodec) isZero(i interface{}) bool {
+	v := reflect.ValueOf(i)
+
+	// check the value validity
+	if !v.IsValid() {
+		return true
+	}
+
+	if z, ok := v.Interface().(Zeroer); ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
+		return z.IsZero()
+	}
+
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+
+	return false
+}
+
+type structDescription struct {
+	fm        map[string]fieldDescription
+	fl        []fieldDescription
+	inlineMap int
+}
+
+type fieldDescription struct {
+	name      string
+	idx       int
+	omitEmpty bool
+	minSize   bool
+	truncate  bool
+	inline    []int
+	encoder   ValueEncoder
+	decoder   ValueDecoder
+}
+
+func (sc *StructCodec) describeStruct(r *Registry, t reflect.Type) (*structDescription, error) {
+	// We need to analyze the struct, including getting the tags, collecting
+	// information about inlining, and create a map of the field name to the field.
+	sc.l.RLock()
+	ds, exists := sc.cache[t]
+	sc.l.RUnlock()
+	if exists {
+		return ds, nil
+	}
+
+	numFields := t.NumField()
+	sd := &structDescription{
+		fm:        make(map[string]fieldDescription, numFields),
+		fl:        make([]fieldDescription, 0, numFields),
+		inlineMap: -1,
+	}
+
+	for i := 0; i < numFields; i++ {
+		sf := t.Field(i)
+		if sf.PkgPath != "" {
+			// unexported, ignore
+			continue
+		}
+
+		encoder, err := r.LookupEncoder(sf.Type)
+		if err != nil {
+			encoder = nil
+		}
+		decoder, err := r.LookupDecoder(sf.Type)
+		if err != nil {
+			decoder = nil
+		}
+
+		description := fieldDescription{idx: i, encoder: encoder, decoder: decoder}
+
+		stags, err := sc.parser.ParseStructTags(sf)
+		if err != nil {
+			return nil, err
+		}
+		if stags.Skip {
+			continue
+		}
+		description.name = stags.Name
+		description.omitEmpty = stags.OmitEmpty
+		description.minSize = stags.MinSize
+		description.truncate = stags.Truncate
+
+		if stags.Inline {
+			switch sf.Type.Kind() {
+			case reflect.Map:
+				if sd.inlineMap >= 0 {
+					return nil, errors.New("(struct " + t.String() + ") multiple inline maps")
+				}
+				if sf.Type.Key() != tString {
+					return nil, errors.New("(struct " + t.String() + ") inline map must have a string keys")
+				}
+				sd.inlineMap = description.idx
+			case reflect.Struct:
+				inlinesf, err := sc.describeStruct(r, sf.Type)
+				if err != nil {
+					return nil, err
+				}
+				for _, fd := range inlinesf.fl {
+					if _, exists := sd.fm[fd.name]; exists {
+						return nil, fmt.Errorf("(struct %s) duplicated key %s", t.String(), fd.name)
+					}
+					if fd.inline == nil {
+						fd.inline = []int{i, fd.idx}
+					} else {
+						fd.inline = append([]int{i}, fd.inline...)
+					}
+					sd.fm[fd.name] = fd
+					sd.fl = append(sd.fl, fd)
+				}
+			default:
+				return nil, fmt.Errorf("(struct %s) inline fields must be either a struct or a map", t.String())
+			}
+			continue
+		}
+
+		if _, exists := sd.fm[description.name]; exists {
+			return nil, fmt.Errorf("struct %s) duplicated key %s", t.String(), description.name)
+		}
+
+		sd.fm[description.name] = description
+		sd.fl = append(sd.fl, description)
+	}
+
+	sc.l.Lock()
+	sc.cache[t] = sd
+	sc.l.Unlock()
+
+	return sd, nil
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/struct_tag_parser.go

@@ -0,0 +1,119 @@
+// 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"
+	"strings"
+)
+
+// StructTagParser returns the struct tags for a given struct field.
+type StructTagParser interface {
+	ParseStructTags(reflect.StructField) (StructTags, error)
+}
+
+// StructTagParserFunc is an adapter that allows a generic function to be used
+// as a StructTagParser.
+type StructTagParserFunc func(reflect.StructField) (StructTags, error)
+
+// ParseStructTags implements the StructTagParser interface.
+func (stpf StructTagParserFunc) ParseStructTags(sf reflect.StructField) (StructTags, error) {
+	return stpf(sf)
+}
+
+// StructTags represents the struct tag fields that the StructCodec uses during
+// the encoding and decoding process.
+//
+// In the case of a struct, the lowercased field name is used as the key for each exported
+// field but this behavior may be changed using a struct tag. The tag may also contain flags to
+// adjust the marshalling behavior for the field.
+//
+// The properties are defined below:
+//
+//     OmitEmpty  Only include the field if it's not set to the zero value for the type or to
+//                empty slices or maps.
+//
+//     MinSize    Marshal an integer of a type larger than 32 bits value as an int32, if that's
+//                feasible while preserving the numeric value.
+//
+//     Truncate   When unmarshaling a BSON double, it is permitted to lose precision to fit within
+//                a float32.
+//
+//     Inline     Inline the field, which must be a struct or a map, causing all of its fields
+//                or keys to be processed as if they were part of the outer struct. For maps,
+//                keys must not conflict with the bson keys of other struct fields.
+//
+//     Skip       This struct field should be skipped. This is usually denoted by parsing a "-"
+//                for the name.
+//
+// TODO(skriptble): Add tags for undefined as nil and for null as nil.
+type StructTags struct {
+	Name      string
+	OmitEmpty bool
+	MinSize   bool
+	Truncate  bool
+	Inline    bool
+	Skip      bool
+}
+
+// DefaultStructTagParser is the StructTagParser used by the StructCodec by default.
+// It will handle the bson struct tag. See the documentation for StructTags to see
+// what each of the returned fields means.
+//
+// If there is no name in the struct tag fields, the struct field name is lowercased.
+// The tag formats accepted are:
+//
+//     "[<key>][,<flag1>[,<flag2>]]"
+//
+//     `(...) bson:"[<key>][,<flag1>[,<flag2>]]" (...)`
+//
+// An example:
+//
+//     type T struct {
+//         A bool
+//         B int    "myb"
+//         C string "myc,omitempty"
+//         D string `bson:",omitempty" json:"jsonkey"`
+//         E int64  ",minsize"
+//         F int64  "myf,omitempty,minsize"
+//     }
+//
+// A struct tag either consisting entirely of '-' or with a bson key with a
+// value consisting entirely of '-' will return a StructTags with Skip true and
+// the remaining fields will be their default values.
+var DefaultStructTagParser StructTagParserFunc = func(sf reflect.StructField) (StructTags, error) {
+	key := strings.ToLower(sf.Name)
+	tag, ok := sf.Tag.Lookup("bson")
+	if !ok && !strings.Contains(string(sf.Tag), ":") && len(sf.Tag) > 0 {
+		tag = string(sf.Tag)
+	}
+	var st StructTags
+	if tag == "-" {
+		st.Skip = true
+		return st, nil
+	}
+
+	for idx, str := range strings.Split(tag, ",") {
+		if idx == 0 && str != "" {
+			key = str
+		}
+		switch str {
+		case "omitempty":
+			st.OmitEmpty = true
+		case "minsize":
+			st.MinSize = true
+		case "truncate":
+			st.Truncate = true
+		case "inline":
+			st.Inline = true
+		}
+	}
+
+	st.Name = key
+
+	return st, nil
+}

vendor/go.mongodb.org/mongo-driver/bson/bsoncodec/types.go

@@ -0,0 +1,80 @@
+// 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 (
+	"encoding/json"
+	"net/url"
+	"reflect"
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
+)
+
+var ptBool = reflect.TypeOf((*bool)(nil))
+var ptInt8 = reflect.TypeOf((*int8)(nil))
+var ptInt16 = reflect.TypeOf((*int16)(nil))
+var ptInt32 = reflect.TypeOf((*int32)(nil))
+var ptInt64 = reflect.TypeOf((*int64)(nil))
+var ptInt = reflect.TypeOf((*int)(nil))
+var ptUint8 = reflect.TypeOf((*uint8)(nil))
+var ptUint16 = reflect.TypeOf((*uint16)(nil))
+var ptUint32 = reflect.TypeOf((*uint32)(nil))
+var ptUint64 = reflect.TypeOf((*uint64)(nil))
+var ptUint = reflect.TypeOf((*uint)(nil))
+var ptFloat32 = reflect.TypeOf((*float32)(nil))
+var ptFloat64 = reflect.TypeOf((*float64)(nil))
+var ptString = reflect.TypeOf((*string)(nil))
+
+var tBool = reflect.TypeOf(false)
+var tFloat32 = reflect.TypeOf(float32(0))
+var tFloat64 = reflect.TypeOf(float64(0))
+var tInt = reflect.TypeOf(int(0))
+var tInt8 = reflect.TypeOf(int8(0))
+var tInt16 = reflect.TypeOf(int16(0))
+var tInt32 = reflect.TypeOf(int32(0))
+var tInt64 = reflect.TypeOf(int64(0))
+var tString = reflect.TypeOf("")
+var tTime = reflect.TypeOf(time.Time{})
+var tUint = reflect.TypeOf(uint(0))
+var tUint8 = reflect.TypeOf(uint8(0))
+var tUint16 = reflect.TypeOf(uint16(0))
+var tUint32 = reflect.TypeOf(uint32(0))
+var tUint64 = reflect.TypeOf(uint64(0))
+
+var tEmpty = reflect.TypeOf((*interface{})(nil)).Elem()
+var tByteSlice = reflect.TypeOf([]byte(nil))
+var tByte = reflect.TypeOf(byte(0x00))
+var tURL = reflect.TypeOf(url.URL{})
+var tJSONNumber = reflect.TypeOf(json.Number(""))
+
+var tValueMarshaler = reflect.TypeOf((*ValueMarshaler)(nil)).Elem()
+var tValueUnmarshaler = reflect.TypeOf((*ValueUnmarshaler)(nil)).Elem()
+var tMarshaler = reflect.TypeOf((*Marshaler)(nil)).Elem()
+var tUnmarshaler = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
+var tProxy = reflect.TypeOf((*Proxy)(nil)).Elem()
+
+var tBinary = reflect.TypeOf(primitive.Binary{})
+var tUndefined = reflect.TypeOf(primitive.Undefined{})
+var tOID = reflect.TypeOf(primitive.ObjectID{})
+var tDateTime = reflect.TypeOf(primitive.DateTime(0))
+var tNull = reflect.TypeOf(primitive.Null{})
+var tRegex = reflect.TypeOf(primitive.Regex{})
+var tCodeWithScope = reflect.TypeOf(primitive.CodeWithScope{})
+var tDBPointer = reflect.TypeOf(primitive.DBPointer{})
+var tJavaScript = reflect.TypeOf(primitive.JavaScript(""))
+var tSymbol = reflect.TypeOf(primitive.Symbol(""))
+var tTimestamp = reflect.TypeOf(primitive.Timestamp{})
+var tDecimal = reflect.TypeOf(primitive.Decimal128{})
+var tMinKey = reflect.TypeOf(primitive.MinKey{})
+var tMaxKey = reflect.TypeOf(primitive.MaxKey{})
+var tD = reflect.TypeOf(primitive.D{})
+var tA = reflect.TypeOf(primitive.A{})
+var tE = reflect.TypeOf(primitive.E{})
+
+var tCoreDocument = reflect.TypeOf(bsoncore.Document{})