From d43747066e65157add02533fb55e815b9fa07859 Mon Sep 17 00:00:00 2001
From: inliquid <inliquid@users.noreply.github.com>
Date: Wed, 2 Jan 2019 20:27:48 +0300
Subject: [PATCH 1/2] - Implemented bson.Getter/Setter interfaces for correct
 marshaling/unmarshaling in MongoDB's BSON binary UUID format with Legacy UUID
 as default kind (0x03). - Introduced SetBSONKind function to make user able
 to set different BSON kind.

---
 codec.go | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/codec.go b/codec.go
index 656892c..b4fc6a2 100644
--- a/codec.go
+++ b/codec.go
@@ -24,7 +24,17 @@ package uuid
 import (
 	"bytes"
 	"encoding/hex"
+	"errors"
 	"fmt"
+
+	"gopkg.in/mgo.v2/bson"
+)
+
+var (
+	// By default Legacy UUID subtype (0x03) is used, see
+	// https://studio3t.com/knowledge-base/articles/mongodb-best-practices-uuid-data/#binary-subtypes-0x03-and-0x04 and
+	// http://bsonspec.org/spec.html for details. Can be changed with SetBSONKind.
+	bsonKind byte = 0x03
 )
 
 // FromBytes returns UUID converted from raw byte slice input.
@@ -204,3 +214,41 @@ func (u *UUID) UnmarshalBinary(data []byte) (err error) {
 
 	return
 }
+
+// GetBSON implements bson.Getter for marshaling UUID in BSON binary UUID format.
+// By default Kind of 0x03 (Legacy UUID) will be used. Can be changed with SetBSONKind.
+func (u UUID) GetBSON() (interface{}, error) {
+	toMarshal := bson.Binary{
+		Kind: bsonKind,
+		Data: u.Bytes(),
+	}
+
+	return toMarshal, nil
+}
+
+// SetBSON implements bson.Setter for unmarshaling UUID from BSON binary UUID format.
+// By default Kind of 0x03 (Legacy UUID) will be used. Can be changed with SetBSONKind.
+func (u *UUID) SetBSON(raw bson.Raw) error {
+	var toUnmarshal bson.Binary
+
+	err := raw.Unmarshal(&toUnmarshal)
+	if err != nil {
+		return err
+	}
+
+	*u, err = FromBytes(toUnmarshal.Data)
+
+	return err
+}
+
+// SetBSONKind changes BSON UUID Kind that will be used by GetBSON and SetBSON. Only value of
+// 0x03 (Legacy UUID) or 0x04 (UUID) can be used, SetBSONKind returns an error when requested value is different.
+func SetBSONKind(kind byte) error {
+	if kind < 0x03 || kind > 0x04 {
+		return errors.New("requested BSON UUID kind is not allowed")
+	}
+
+	bsonKind = kind
+
+	return nil
+}

From 186ab3502a6e4f26a34dbece9e80c1a79ad7ad92 Mon Sep 17 00:00:00 2001
From: inliquid <inliquid@users.noreply.github.com>
Date: Thu, 3 Jan 2019 16:54:20 +0300
Subject: [PATCH 2/2] - Default BSON kind changed to new UUID instead of Legacy
 UUID - Comments changed accordingly

---
 codec.go | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/codec.go b/codec.go
index b4fc6a2..0367fae 100644
--- a/codec.go
+++ b/codec.go
@@ -31,10 +31,10 @@ import (
 )
 
 var (
-	// By default Legacy UUID subtype (0x03) is used, see
+	// By default, new (recommended) UUID subtype/kind (0x04) is used, see
 	// https://studio3t.com/knowledge-base/articles/mongodb-best-practices-uuid-data/#binary-subtypes-0x03-and-0x04 and
 	// http://bsonspec.org/spec.html for details. Can be changed with SetBSONKind.
-	bsonKind byte = 0x03
+	bsonKind byte = 0x04
 )
 
 // FromBytes returns UUID converted from raw byte slice input.
@@ -216,7 +216,7 @@ func (u *UUID) UnmarshalBinary(data []byte) (err error) {
 }
 
 // GetBSON implements bson.Getter for marshaling UUID in BSON binary UUID format.
-// By default Kind of 0x03 (Legacy UUID) will be used. Can be changed with SetBSONKind.
+// By default Kind of 0x04 (new UUID) will be used. Can be changed with SetBSONKind.
 func (u UUID) GetBSON() (interface{}, error) {
 	toMarshal := bson.Binary{
 		Kind: bsonKind,
@@ -227,7 +227,7 @@ func (u UUID) GetBSON() (interface{}, error) {
 }
 
 // SetBSON implements bson.Setter for unmarshaling UUID from BSON binary UUID format.
-// By default Kind of 0x03 (Legacy UUID) will be used. Can be changed with SetBSONKind.
+// By default Kind of 0x04 (new UUID) will be used. Can be changed with SetBSONKind.
 func (u *UUID) SetBSON(raw bson.Raw) error {
 	var toUnmarshal bson.Binary
 
@@ -241,8 +241,8 @@ func (u *UUID) SetBSON(raw bson.Raw) error {
 	return err
 }
 
-// SetBSONKind changes BSON UUID Kind that will be used by GetBSON and SetBSON. Only value of
-// 0x03 (Legacy UUID) or 0x04 (UUID) can be used, SetBSONKind returns an error when requested value is different.
+// SetBSONKind changes BSON UUID Kind which will be used by GetBSON and SetBSON. Only values of
+// 0x03 (Legacy UUID) or 0x04 (new UUID) can be used, SetBSONKind returns error when requested kind is different.
 func SetBSONKind(kind byte) error {
 	if kind < 0x03 || kind > 0x04 {
 		return errors.New("requested BSON UUID kind is not allowed")