feat: Export msgpack ext encode/decode functions

Fixes #420.

CHANGELOG.md

@@ -12,6 +12,9 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
 
 ### Changed
 
+- Made MessagePack extension encoding and decoding functions exportable, 
+  allowing users to reuse the logic for custom extensions (#421).
+
 ### Fixed
 
 ## [v2.2.0] - 2024-12-16

arrow/arrow.go

@@ -7,8 +7,8 @@ import (
 	"github.com/vmihailenco/msgpack/v5"
 )
 
-// Arrow MessagePack extension type.
-const arrowExtId = 8
+// ExtID represents the Arrow MessagePack extension type identifier.
+const ExtID = 8
 
 // Arrow struct wraps a raw arrow data buffer.
 type Arrow struct {
@@ -26,31 +26,31 @@ func (a Arrow) Raw() []byte {
 	return a.data
 }
 
-func arrowDecoder(d *msgpack.Decoder, v reflect.Value, extLen int) error {
+func DecodeExt(d *msgpack.Decoder, v reflect.Value, extLen int) error {
 	arrow := Arrow{
 		data: make([]byte, extLen),
 	}
 	n, err := d.Buffered().Read(arrow.data)
 	if err != nil {
-		return fmt.Errorf("arrowDecoder: can't read bytes on Arrow decode: %w", err)
+		return fmt.Errorf("decode: can't read bytes on Arrow decode: %w", err)
 	}
 	if n < extLen || n != len(arrow.data) {
-		return fmt.Errorf("arrowDecoder: unexpected end of stream after %d Arrow bytes", n)
+		return fmt.Errorf("decode: unexpected end of stream after %d Arrow bytes", n)
 	}
 
 	v.Set(reflect.ValueOf(arrow))
 	return nil
 }
 
-func arrowEncoder(e *msgpack.Encoder, v reflect.Value) ([]byte, error) {
+func EncodeExt(_ *msgpack.Encoder, v reflect.Value) ([]byte, error) {
 	arr, ok := v.Interface().(Arrow)
 	if !ok {
-		return []byte{}, fmt.Errorf("arrowEncoder: not an Arrow type")
+		return []byte{}, fmt.Errorf("encode: not an Arrow type")
 	}
 	return arr.data, nil
 }
 
 func init() {
-	msgpack.RegisterExtDecoder(arrowExtId, Arrow{}, arrowDecoder)
-	msgpack.RegisterExtEncoder(arrowExtId, Arrow{}, arrowEncoder)
+	msgpack.RegisterExtDecoder(ExtID, Arrow{}, DecodeExt)
+	msgpack.RegisterExtEncoder(ExtID, Arrow{}, EncodeExt)
 }

datetime/datetime.go

@@ -1,4 +1,4 @@
-// Package with support of Tarantool's datetime data type.
+// Package datetime provides support for Tarantool's datetime data type.
 //
 // Datetime data type supported in Tarantool since 2.10.
 //
@@ -34,9 +34,10 @@ import (
 // * [optional] all the other fields (nsec, tzoffset, tzindex) if any of them
 // were having not 0 value. They are packed naturally in little-endian order;
 
-// Datetime external type. Supported since Tarantool 2.10. See more details in
+// ExtID represents the Datetime MessagePack extension type identifier.
+// Supported since Tarantool 2.10. See more details in
 // issue https://github.com/tarantool/tarantool/issues/5946.
-const datetimeExtID = 4
+const ExtID = 4
 
 // datetime structure keeps a number of seconds and nanoseconds since Unix Epoch.
 // Time is normalized by UTC, so time-zone offset is informative only.
@@ -242,7 +243,7 @@ func (d *Datetime) ToTime() time.Time {
 	return d.time
 }
 
-func datetimeEncoder(e *msgpack.Encoder, v reflect.Value) ([]byte, error) {
+func EncodeExt(_ *msgpack.Encoder, v reflect.Value) ([]byte, error) {
 	dtime := v.Interface().(Datetime)
 	tm := dtime.ToTime()
 
@@ -275,7 +276,7 @@ func datetimeEncoder(e *msgpack.Encoder, v reflect.Value) ([]byte, error) {
 	return buf, nil
 }
 
-func datetimeDecoder(d *msgpack.Decoder, v reflect.Value, extLen int) error {
+func DecodeExt(d *msgpack.Decoder, v reflect.Value, extLen int) error {
 	if extLen != maxSize && extLen != secondsSize {
 		return fmt.Errorf("invalid data length: got %d, wanted %d or %d",
 			extLen, secondsSize, maxSize)
@@ -333,6 +334,6 @@ func datetimeDecoder(d *msgpack.Decoder, v reflect.Value, extLen int) error {
 }
 
 func init() {
-	msgpack.RegisterExtDecoder(datetimeExtID, Datetime{}, datetimeDecoder)
-	msgpack.RegisterExtEncoder(datetimeExtID, Datetime{}, datetimeEncoder)
+	msgpack.RegisterExtDecoder(ExtID, Datetime{}, DecodeExt)
+	msgpack.RegisterExtEncoder(ExtID, Datetime{}, EncodeExt)
 }

datetime/interval.go

@@ -8,7 +8,8 @@ import (
 	"github.com/vmihailenco/msgpack/v5"
 )
 
-const interval_extId = 6
+// IntervalExtID represents the Interval MessagePack extension type identifier.
+const IntervalExtID = 6
 
 const (
 	fieldYear   = 0
@@ -74,7 +75,7 @@ func encodeIntervalValue(e *msgpack.Encoder, typ uint64, value int64) (err error
 	if err == nil {
 		if value > 0 {
 			err = e.EncodeUint(uint64(value))
-		} else if value < 0 {
+		} else {
 			err = e.EncodeInt(value)
 		}
 	}
@@ -181,20 +182,22 @@ func decodeInterval(d *msgpack.Decoder, v reflect.Value) (err error) {
 	return nil
 }
 
-func init() {
-	msgpack.RegisterExtEncoder(interval_extId, Interval{},
-		func(e *msgpack.Encoder, v reflect.Value) (ret []byte, err error) {
-			var b bytes.Buffer
+func EncodeIntervalExt(_ *msgpack.Encoder, v reflect.Value) (ret []byte, err error) {
+	var b bytes.Buffer
 
-			enc := msgpack.NewEncoder(&b)
-			if err = encodeInterval(enc, v); err == nil {
-				ret = b.Bytes()
-			}
+	enc := msgpack.NewEncoder(&b)
+	if err = encodeInterval(enc, v); err == nil {
+		ret = b.Bytes()
+	}
 
-			return
-		})
-	msgpack.RegisterExtDecoder(interval_extId, Interval{},
-		func(d *msgpack.Decoder, v reflect.Value, extLen int) error {
-			return decodeInterval(d, v)
-		})
+	return
+}
+
+func DecodeIntervalExt(d *msgpack.Decoder, v reflect.Value, _ int) error {
+	return decodeInterval(d, v)
+}
+
+func init() {
+	msgpack.RegisterExtEncoder(IntervalExtID, Interval{}, EncodeIntervalExt)
+	msgpack.RegisterExtDecoder(IntervalExtID, Interval{}, DecodeIntervalExt)
 }

decimal/decimal.go

@@ -1,4 +1,4 @@
-// Package decimal with support of Tarantool's decimal data type.
+// Package decimal provides support for Tarantool's decimal data type.
 //
 // Decimal data type supported in Tarantool since 2.2.
 //
@@ -37,11 +37,10 @@ import (
 // - Tarantool module decimal:
 //   https://www.tarantool.io/en/doc/latest/reference/reference_lua/decimal/
 
-const (
-	// Decimal external type.
-	decimalExtID     = 1
-	decimalPrecision = 38
-)
+// ExtID represents the Decimal MessagePack extension type identifier.
+const ExtID = 1
+
+const decimalPrecision = 38
 
 var (
 	one decimal.Decimal = decimal.NewFromInt(1)
@@ -71,7 +70,7 @@ func MakeDecimalFromString(src string) (Decimal, error) {
 	return result, nil
 }
 
-func decimalEncoder(e *msgpack.Encoder, v reflect.Value) ([]byte, error) {
+func EncodeExt(_ *msgpack.Encoder, v reflect.Value) ([]byte, error) {
 	dec := v.Interface().(Decimal)
 	if dec.GreaterThan(maxSupportedDecimal) {
 		return nil,
@@ -94,7 +93,7 @@ func decimalEncoder(e *msgpack.Encoder, v reflect.Value) ([]byte, error) {
 	return bcdBuf, nil
 }
 
-func decimalDecoder(d *msgpack.Decoder, v reflect.Value, extLen int) error {
+func DecodeExt(d *msgpack.Decoder, v reflect.Value, extLen int) error {
 	b := make([]byte, extLen)
 	n, err := d.Buffered().Read(b)
 	if err != nil {
@@ -131,6 +130,6 @@ func decimalDecoder(d *msgpack.Decoder, v reflect.Value, extLen int) error {
 }
 
 func init() {
-	msgpack.RegisterExtDecoder(decimalExtID, Decimal{}, decimalDecoder)
-	msgpack.RegisterExtEncoder(decimalExtID, Decimal{}, decimalEncoder)
+	msgpack.RegisterExtDecoder(ExtID, Decimal{}, DecodeExt)
+	msgpack.RegisterExtEncoder(ExtID, Decimal{}, EncodeExt)
 }

uuid/uuid.go

@@ -1,4 +1,4 @@
-// Package with support of Tarantool's UUID data type.
+// Package uuid provides support for Tarantool's UUID data type.
 //
 // UUID data type supported in Tarantool since 2.4.1.
 //
@@ -24,8 +24,8 @@ import (
 	"github.com/vmihailenco/msgpack/v5"
 )
 
-// UUID external type.
-const uuid_extID = 2
+// ExtID represents the UUID MessagePack extension type identifier.
+const ExtID = 2
 
 func encodeUUID(e *msgpack.Encoder, v reflect.Value) error {
 	id := v.Interface().(uuid.UUID)
@@ -64,15 +64,17 @@ func decodeUUID(d *msgpack.Decoder, v reflect.Value) error {
 	return nil
 }
 
+func EncodeExt(_ *msgpack.Encoder, v reflect.Value) ([]byte, error) {
+	u := v.Interface().(uuid.UUID)
+	return u.MarshalBinary()
+}
+
+func DecodeExt(d *msgpack.Decoder, v reflect.Value, _ int) error {
+	return decodeUUID(d, v)
+}
+
 func init() {
 	msgpack.Register(reflect.TypeOf((*uuid.UUID)(nil)).Elem(), encodeUUID, decodeUUID)
-	msgpack.RegisterExtEncoder(uuid_extID, uuid.UUID{},
-		func(e *msgpack.Encoder, v reflect.Value) ([]byte, error) {
-			uuid := v.Interface().(uuid.UUID)
-			return uuid.MarshalBinary()
-		})
-	msgpack.RegisterExtDecoder(uuid_extID, uuid.UUID{},
-		func(d *msgpack.Decoder, v reflect.Value, extLen int) error {
-			return decodeUUID(d, v)
-		})
+	msgpack.RegisterExtEncoder(ExtID, uuid.UUID{}, EncodeExt)
+	msgpack.RegisterExtDecoder(ExtID, uuid.UUID{}, DecodeExt)
 }