Merge remote-tracking branch 'origin/tl-decoder'

liteclient/decoder.go

@@ -0,0 +1,56 @@
+package liteclient
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"github.com/tonkeeper/tongo/tl"
+	"reflect"
+)
+
+func pointer[T any](t T) *T {
+	return &t
+}
+
+type RequestName = string
+
+const (
+	UnknownRequest RequestName = "Unknown"
+)
+
+func decodeRequest(tag uint32, name RequestName, msgType any) reqDecoderFunc {
+	return func(b []byte) (*RequestName, any, error) {
+		if len(b) < 4 {
+			return nil, nil, errors.New("message too short")
+		}
+		readTag := binary.LittleEndian.Uint32(b[:4])
+		if readTag != tag {
+			return nil, nil, fmt.Errorf("invalid tag")
+		}
+		body := reflect.New(reflect.TypeOf(msgType))
+		reader := bytes.NewReader(b[4:])
+		err := tl.Unmarshal(reader, body.Interface())
+		if err == nil {
+			return pointer(name), body.Elem().Interface(), nil
+		}
+		return nil, nil, err
+	}
+}
+
+type reqDecoderFunc func(b []byte) (*RequestName, any, error)
+
+func LiteapiRequestDecoder(b []byte) (uint32, *RequestName, any, error) {
+	if len(b) < 4 {
+		return 0, nil, nil, errors.New("message too short")
+	}
+	tag := binary.LittleEndian.Uint32(b[:4])
+	f := taggedRequestDecodeFunctions[tag]
+	if f != nil {
+		o, d, err := f(b)
+		if err == nil {
+			return tag, o, d, nil
+		}
+	}
+	return tag, pointer(UnknownRequest), nil, nil
+}