Copied mongo repo (to patch it)

mongo/bson/mgocompat/doc.go

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+// Copyright (C) MongoDB, Inc. 2022-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 mgocompat provides Registry, a BSON registry compatible with globalsign/mgo's BSON,
+// with some remaining differences. It also provides RegistryRespectNilValues for compatibility
+// with mgo's BSON with RespectNilValues set to true. A registry can be configured on a
+// mongo.Client with the SetRegistry option. See the bsoncodec docs for more details on registries.
+//
+// Registry supports Getter and Setter equivalents by registering hooks. Note that if a value
+// matches the hook for bsoncodec.Marshaler, bsoncodec.ValueMarshaler, or bsoncodec.Proxy, that
+// hook will take priority over the Getter hook. The same is true for the hooks for
+// bsoncodec.Unmarshaler and bsoncodec.ValueUnmarshaler and the Setter hook.
+//
+// The functional differences between Registry and globalsign/mgo's BSON library are:
+//
+// 1) Registry errors instead of silently skipping mismatched types when decoding.
+//
+// 2) Registry does not have special handling for marshaling array ops ("$in", "$nin", "$all").
+//
+// The driver uses different types than mgo's bson. The differences are:
+//
+//  1. The driver's bson.RawValue is equivalent to mgo's bson.Raw, but uses Value instead of Data and uses Type,
+//     which is a bsontype.Type object that wraps a byte, instead of bson.Raw's Kind, a byte.
+//
+//  2. The driver uses primitive.ObjectID, which is a [12]byte instead of mgo's
+//     bson.ObjectId, a string. Due to this, the zero value marshals and unmarshals differently
+//     for Extended JSON, with the driver marshaling as {"ID":"000000000000000000000000"} and
+//     mgo as {"Id":""}. The driver can unmarshal {"ID":""} to a primitive.ObjectID.
+//
+//  3. The driver's primitive.Symbol is equivalent to mgo's bson.Symbol.
+//
+//  4. The driver uses primitive.Timestamp instead of mgo's bson.MongoTimestamp. While
+//     MongoTimestamp is an int64, primitive.Timestamp stores the time and counter as two separate
+//     uint32 values, T and I respectively.
+//
+//  5. The driver uses primitive.MinKey and primitive.MaxKey, which are struct{}, instead
+//     of mgo's bson.MinKey and bson.MaxKey, which are int64.
+//
+//  6. The driver's primitive.Undefined is equivalent to mgo's bson.Undefined.
+//
+//  7. The driver's primitive.Binary is equivalent to mgo's bson.Binary, with variables named Subtype
+//     and Data instead of Kind and Data.
+//
+//  8. The driver's primitive.Regex is equivalent to mgo's bson.RegEx.
+//
+//  9. The driver's primitive.JavaScript is equivalent to mgo's bson.JavaScript with no
+//     scope and primitive.CodeWithScope is equivalent to mgo's bson.JavaScript with scope.
+//
+//  10. The driver's primitive.DBPointer is equivalent to mgo's bson.DBPointer, with variables
+//     named DB and Pointer instead of Namespace and Id.
+//
+//  11. When implementing the Setter interface, mgocompat.ErrSetZero is equivalent to mgo's
+//     bson.ErrSetZero.
+package mgocompat

mongo/bson/mgocompat/registry.go

@@ -0,0 +1,114 @@
+// 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 mgocompat
+
+import (
+	"errors"
+	"reflect"
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/bsoncodec"
+	"go.mongodb.org/mongo-driver/bson/bsonoptions"
+	"go.mongodb.org/mongo-driver/bson/bsontype"
+)
+
+var (
+	// ErrSetZero may be returned from a SetBSON method to have the value set to its respective zero value.
+	ErrSetZero = errors.New("set to zero")
+
+	tInt            = reflect.TypeOf(int(0))
+	tTime           = reflect.TypeOf(time.Time{})
+	tM              = reflect.TypeOf(bson.M{})
+	tInterfaceSlice = reflect.TypeOf([]interface{}{})
+	tByteSlice      = reflect.TypeOf([]byte{})
+	tEmpty          = reflect.TypeOf((*interface{})(nil)).Elem()
+	tGetter         = reflect.TypeOf((*Getter)(nil)).Elem()
+	tSetter         = reflect.TypeOf((*Setter)(nil)).Elem()
+)
+
+// Registry is the mgo compatible bsoncodec.Registry. It contains the default and
+// primitive codecs with mgo compatible options.
+var Registry = NewRegistryBuilder().Build()
+
+// RegistryRespectNilValues is the bsoncodec.Registry compatible with mgo withSetRespectNilValues set to true.
+var RegistryRespectNilValues = NewRespectNilValuesRegistryBuilder().Build()
+
+// NewRegistryBuilder creates a new bsoncodec.RegistryBuilder configured with the default encoders and
+// decoders from the bsoncodec.DefaultValueEncoders and bsoncodec.DefaultValueDecoders types and the
+// PrimitiveCodecs type in this package.
+func NewRegistryBuilder() *bsoncodec.RegistryBuilder {
+	rb := bsoncodec.NewRegistryBuilder()
+	bsoncodec.DefaultValueEncoders{}.RegisterDefaultEncoders(rb)
+	bsoncodec.DefaultValueDecoders{}.RegisterDefaultDecoders(rb)
+	bson.PrimitiveCodecs{}.RegisterPrimitiveCodecs(rb)
+
+	structcodec, _ := bsoncodec.NewStructCodec(bsoncodec.DefaultStructTagParser,
+		bsonoptions.StructCodec().
+			SetDecodeZeroStruct(true).
+			SetEncodeOmitDefaultStruct(true).
+			SetOverwriteDuplicatedInlinedFields(false).
+			SetAllowUnexportedFields(true))
+	emptyInterCodec := bsoncodec.NewEmptyInterfaceCodec(
+		bsonoptions.EmptyInterfaceCodec().
+			SetDecodeBinaryAsSlice(true))
+	mapCodec := bsoncodec.NewMapCodec(
+		bsonoptions.MapCodec().
+			SetDecodeZerosMap(true).
+			SetEncodeNilAsEmpty(true).
+			SetEncodeKeysWithStringer(true))
+	uintcodec := bsoncodec.NewUIntCodec(bsonoptions.UIntCodec().SetEncodeToMinSize(true))
+
+	rb.RegisterTypeDecoder(tEmpty, emptyInterCodec).
+		RegisterDefaultDecoder(reflect.String, bsoncodec.NewStringCodec(bsonoptions.StringCodec().SetDecodeObjectIDAsHex(false))).
+		RegisterDefaultDecoder(reflect.Struct, structcodec).
+		RegisterDefaultDecoder(reflect.Map, mapCodec).
+		RegisterTypeEncoder(tByteSlice, bsoncodec.NewByteSliceCodec(bsonoptions.ByteSliceCodec().SetEncodeNilAsEmpty(true))).
+		RegisterDefaultEncoder(reflect.Struct, structcodec).
+		RegisterDefaultEncoder(reflect.Slice, bsoncodec.NewSliceCodec(bsonoptions.SliceCodec().SetEncodeNilAsEmpty(true))).
+		RegisterDefaultEncoder(reflect.Map, mapCodec).
+		RegisterDefaultEncoder(reflect.Uint, uintcodec).
+		RegisterDefaultEncoder(reflect.Uint8, uintcodec).
+		RegisterDefaultEncoder(reflect.Uint16, uintcodec).
+		RegisterDefaultEncoder(reflect.Uint32, uintcodec).
+		RegisterDefaultEncoder(reflect.Uint64, uintcodec).
+		RegisterTypeMapEntry(bsontype.Int32, tInt).
+		RegisterTypeMapEntry(bsontype.DateTime, tTime).
+		RegisterTypeMapEntry(bsontype.Array, tInterfaceSlice).
+		RegisterTypeMapEntry(bsontype.Type(0), tM).
+		RegisterTypeMapEntry(bsontype.EmbeddedDocument, tM).
+		RegisterHookEncoder(tGetter, bsoncodec.ValueEncoderFunc(GetterEncodeValue)).
+		RegisterHookDecoder(tSetter, bsoncodec.ValueDecoderFunc(SetterDecodeValue))
+
+	return rb
+}
+
+// NewRespectNilValuesRegistryBuilder creates a new bsoncodec.RegistryBuilder configured to behave like mgo/bson
+// with RespectNilValues set to true.
+func NewRespectNilValuesRegistryBuilder() *bsoncodec.RegistryBuilder {
+	rb := NewRegistryBuilder()
+
+	structcodec, _ := bsoncodec.NewStructCodec(bsoncodec.DefaultStructTagParser,
+		bsonoptions.StructCodec().
+			SetDecodeZeroStruct(true).
+			SetEncodeOmitDefaultStruct(true).
+			SetOverwriteDuplicatedInlinedFields(false).
+			SetAllowUnexportedFields(true))
+	mapCodec := bsoncodec.NewMapCodec(
+		bsonoptions.MapCodec().
+			SetDecodeZerosMap(true).
+			SetEncodeNilAsEmpty(false))
+
+	rb.RegisterDefaultDecoder(reflect.Struct, structcodec).
+		RegisterDefaultDecoder(reflect.Map, mapCodec).
+		RegisterTypeEncoder(tByteSlice, bsoncodec.NewByteSliceCodec(bsonoptions.ByteSliceCodec().SetEncodeNilAsEmpty(false))).
+		RegisterDefaultEncoder(reflect.Struct, structcodec).
+		RegisterDefaultEncoder(reflect.Slice, bsoncodec.NewSliceCodec(bsonoptions.SliceCodec().SetEncodeNilAsEmpty(false))).
+		RegisterDefaultEncoder(reflect.Map, mapCodec)
+
+	return rb
+}

mongo/bson/mgocompat/setter_getter.go

@@ -0,0 +1,127 @@
+// 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 mgocompat
+
+import (
+	"reflect"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/bsoncodec"
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
+)
+
+// Setter interface: a value implementing the bson.Setter interface will receive the BSON
+// value via the SetBSON method during unmarshaling, and the object
+// itself will not be changed as usual.
+//
+// If setting the value works, the method should return nil or alternatively
+// mgocompat.ErrSetZero to set the respective field to its zero value (nil for
+// pointer types). If SetBSON returns a non-nil error, the unmarshalling
+// procedure will stop and error out with the provided value.
+//
+// This interface is generally useful in pointer receivers, since the method
+// will want to change the receiver. A type field that implements the Setter
+// interface doesn't have to be a pointer, though.
+//
+// For example:
+//
+//	type MyString string
+//
+//	func (s *MyString) SetBSON(raw bson.RawValue) error {
+//	    return raw.Unmarshal(s)
+//	}
+type Setter interface {
+	SetBSON(raw bson.RawValue) error
+}
+
+// Getter interface: a value implementing the bson.Getter interface will have its GetBSON
+// method called when the given value has to be marshalled, and the result
+// of this method will be marshaled in place of the actual object.
+//
+// If GetBSON returns return a non-nil error, the marshalling procedure
+// will stop and error out with the provided value.
+type Getter interface {
+	GetBSON() (interface{}, error)
+}
+
+// SetterDecodeValue is the ValueDecoderFunc for Setter types.
+func SetterDecodeValue(dc bsoncodec.DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
+	if !val.IsValid() || (!val.Type().Implements(tSetter) && !reflect.PtrTo(val.Type()).Implements(tSetter)) {
+		return bsoncodec.ValueDecoderError{Name: "SetterDecodeValue", Types: []reflect.Type{tSetter}, Received: val}
+	}
+
+	if val.Kind() == reflect.Ptr && val.IsNil() {
+		if !val.CanSet() {
+			return bsoncodec.ValueDecoderError{Name: "SetterDecodeValue", Types: []reflect.Type{tSetter}, Received: val}
+		}
+		val.Set(reflect.New(val.Type().Elem()))
+	}
+
+	if !val.Type().Implements(tSetter) {
+		if !val.CanAddr() {
+			return bsoncodec.ValueDecoderError{Name: "ValueUnmarshalerDecodeValue", Types: []reflect.Type{tSetter}, Received: val}
+		}
+		val = val.Addr() // If the type doesn't implement the interface, a pointer to it must.
+	}
+
+	t, src, err := bsonrw.Copier{}.CopyValueToBytes(vr)
+	if err != nil {
+		return err
+	}
+
+	fn := val.Convert(tSetter).MethodByName("SetBSON")
+
+	errVal := fn.Call([]reflect.Value{reflect.ValueOf(bson.RawValue{Type: t, Value: src})})[0]
+	if !errVal.IsNil() {
+		err = errVal.Interface().(error)
+		if err == ErrSetZero {
+			val.Set(reflect.Zero(val.Type()))
+			return nil
+		}
+		return err
+	}
+	return nil
+}
+
+// GetterEncodeValue is the ValueEncoderFunc for Getter types.
+func GetterEncodeValue(ec bsoncodec.EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	// Either val or a pointer to val must implement Getter
+	switch {
+	case !val.IsValid():
+		return bsoncodec.ValueEncoderError{Name: "GetterEncodeValue", Types: []reflect.Type{tGetter}, Received: val}
+	case val.Type().Implements(tGetter):
+		// If Getter is implemented on a concrete type, make sure that val isn't a nil pointer
+		if isImplementationNil(val, tGetter) {
+			return vw.WriteNull()
+		}
+	case reflect.PtrTo(val.Type()).Implements(tGetter) && val.CanAddr():
+		val = val.Addr()
+	default:
+		return bsoncodec.ValueEncoderError{Name: "GetterEncodeValue", Types: []reflect.Type{tGetter}, Received: val}
+	}
+
+	fn := val.Convert(tGetter).MethodByName("GetBSON")
+	returns := fn.Call(nil)
+	if !returns[1].IsNil() {
+		return returns[1].Interface().(error)
+	}
+	intermediate := returns[0]
+	encoder, err := ec.Registry.LookupEncoder(intermediate.Type())
+	if err != nil {
+		return err
+	}
+	return encoder.EncodeValue(ec, vw, intermediate)
+}
+
+// isImplementationNil returns if val is a nil pointer and inter is implemented on a concrete type
+func isImplementationNil(val reflect.Value, inter reflect.Type) bool {
+	vt := val.Type()
+	for vt.Kind() == reflect.Ptr {
+		vt = vt.Elem()
+	}
+	return vt.Implements(inter) && val.Kind() == reflect.Ptr && val.IsNil()
+}