Add pk.Option API

bot/mcbot.go

@@ -79,22 +79,20 @@ func (c *Client) join(ctx context.Context, d *mcnet.Dialer, addr string) error {
 	}
 	// Login Start
 	c.KeyPair, err = user.GetOrFetchKeyPair(c.Auth.AsTk)
-	HasSignature := err == nil
+	KeyPair := pk.Option[keyPair]{
+		Has: err == nil,
+		Val: keyPair(c.KeyPair),
+	}
 	c.UUID, err = uuid.Parse(c.Auth.UUID)
-	HasPlayerUUID := err == nil
+	PlayerUUID := pk.Option[pk.UUID]{
+		Has: err == nil,
+		Val: pk.UUID(c.UUID),
+	}
 	err = c.Conn.WritePacket(pk.Marshal(
 		packetid.LoginStart,
 		pk.String(c.Auth.Name),
-		pk.Boolean(HasSignature),
+		KeyPair,
-		pk.Opt{
+		PlayerUUID,
-			Has:   HasSignature,
-			Field: keyPair(c.KeyPair),
-		},
-		pk.Boolean(HasPlayerUUID),
-		pk.Opt{
-			Has:   HasPlayerUUID,
-			Field: pk.UUID(c.UUID),
-		},
 	))
 	if err != nil {
 		return LoginErr{"login start", err}
@@ -148,9 +146,10 @@ func (c *Client) join(ctx context.Context, d *mcnet.Dialer, addr string) error {
 				return LoginErr{"Login Plugin", err}
 			}
 
-			handler, ok := c.LoginPlugin[string(channel)]
+			var PluginMessageData pk.Option[pk.PluginMessageData]
-			if ok {
+			if handler, ok := c.LoginPlugin[string(channel)]; ok {
-				data, err = handler(data)
+				PluginMessageData.Has = true
+				PluginMessageData.Val, err = handler(data)
 				if err != nil {
 					return LoginErr{"Login Plugin", err}
 				}
@@ -158,8 +157,7 @@ func (c *Client) join(ctx context.Context, d *mcnet.Dialer, addr string) error {
 
 			if err := c.Conn.WritePacket(pk.Marshal(
 				packetid.LoginPluginResponse,
-				msgid, pk.Boolean(ok),
+				msgid, PluginMessageData,
-				pk.Opt{Has: ok, Field: data},
 			)); err != nil {
 				return LoginErr{"login Plugin", err}
 			}

chat/message.go

@@ -11,6 +11,7 @@
 package chat
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -113,6 +114,7 @@ func (m Message) MarshalJSON() ([]byte, error) {
 
 // UnmarshalJSON decode json to Message
 func (m *Message) UnmarshalJSON(raw []byte) (err error) {
+	raw = bytes.TrimSpace(raw)
 	if len(raw) == 0 {
 		return io.EOF
 	}

net/packet/util.go

@@ -7,6 +7,12 @@ import (
 	"reflect"
 )
 
+var (
+	_ Field = (*Option[Field])(nil)
+	_ Field = (*Ary[VarInt])(nil)
+	_ Field = Tuple(nil)
+)
+
 // Ary is used to send or receive the packet field like "Array of X"
 // which has a count must be known from the context.
 //
@@ -19,16 +25,16 @@ import (
 // So it's allowed to directly set an integer type Len, but not a pointer.
 //
 // Note that Ary DO read or write the Len. You aren't need to do so by your self.
-type Ary[T VarInt | VarLong | Byte | UnsignedByte | Short | UnsignedShort | Int | Long] struct {
+type Ary[LEN VarInt | VarLong | Byte | UnsignedByte | Short | UnsignedShort | Int | Long] struct {
 	Ary interface{} // Slice or Pointer of Slice of FieldEncoder, FieldDecoder or both (Field)
 }
 
-func (a Ary[T]) WriteTo(w io.Writer) (n int64, err error) {
+func (a Ary[LEN]) WriteTo(w io.Writer) (n int64, err error) {
 	array := reflect.ValueOf(a.Ary)
 	for array.Kind() == reflect.Ptr {
 		array = array.Elem()
 	}
-	Len := T(array.Len())
+	Len := LEN(array.Len())
 	if nn, err := any(&Len).(FieldEncoder).WriteTo(w); err != nil {
 		return n, err
 	} else {
@@ -45,8 +51,8 @@ func (a Ary[T]) WriteTo(w io.Writer) (n int64, err error) {
 	return n, nil
 }
 
-func (a Ary[T]) ReadFrom(r io.Reader) (n int64, err error) {
+func (a Ary[LEN]) ReadFrom(r io.Reader) (n int64, err error) {
-	var Len T
+	var Len LEN
 	if nn, err := any(&Len).(FieldDecoder).ReadFrom(r); err != nil {
 		return nn, err
 	} else {
@@ -133,7 +139,33 @@ func (o Opt) ReadFrom(r io.Reader) (int64, error) {
 	return 0, nil
 }
 
-type Tuple []interface{} // FieldEncoder, FieldDecoder or both (Field)
+type Option[T any] struct {
+	Has Boolean
+	Val T
+}
+
+func (o Option[T]) WriteTo(w io.Writer) (n int64, err error) {
+	n1, err := o.Has.WriteTo(w)
+	if err != nil || !o.Has {
+		return n1, err
+	}
+	n2, err := any(&o.Val).(FieldEncoder).WriteTo(w)
+	return n1 + n2, err
+}
+
+func (o *Option[T]) ReadFrom(r io.Reader) (n int64, err error) {
+	n1, err := o.Has.ReadFrom(r)
+	if err != nil || !o.Has {
+		return n1, err
+	}
+	// This lose performance, but current Golang doesn't provide any better solution.
+	// I hope Go support we declare type constraint like `Option[*T Field]` in the future
+	// and then we can prevent using any dynamic dispatch.
+	n2, err := any(&o.Val).(FieldDecoder).ReadFrom(r)
+	return n1 + n2, err
+}
+
+type Tuple []any // FieldEncoder, FieldDecoder or both (Field)
 
 // WriteTo write Tuple to io.Writer, panic when any of filed don't implement FieldEncoder
 func (t Tuple) WriteTo(w io.Writer) (n int64, err error) {

net/packet/util_test.go

@@ -138,7 +138,6 @@ func ExampleOpt_ReadFrom() {
 	// WILL NOT BE READ, WILL NOT BE COVERED
 }
 
-func ExampleOpt_ReadFrom_func() {
 // As an example, we define this packet as this:
 // +------+-----------------+----------------------------------+
 // | Name | Type            | Notes                            |
@@ -148,6 +147,7 @@ func ExampleOpt_ReadFrom_func() {
 // | User | Optional String | The player's name.               |
 // +------+-----------------+----------------------------------+
 // So we need a function to decide if the User field is present.
+func ExampleOpt_ReadFrom_func() {
 	var flag pk.Byte
 	var data pk.String
 	p := pk.Packet{Data: []byte{
@@ -188,3 +188,38 @@ func ExampleTuple_ReadFrom() {
 		panic(err)
 	}
 }
+
+// As an example, we define this packet as this:
+// +------+-----------------+-----------------------------------+
+// | Name | Type            | Notes                             |
+// +------+-----------------+-----------------------------------+
+// | Has  | Boolean         | True if the following is present. |
+// +------+-----------------+-----------------------------------+
+// | User | Optional String | The player's name.                |
+// +------+-----------------+-----------------------------------+
+// So we need a function to decide if the User field is present.
+func ExampleOption_ReadFrom_func() {
+	p1 := pk.Packet{Data: []byte{
+		0x01,                  // pk.Boolean(true)
+		4, 'T', 'n', 'z', 'e', // pk.String("Tnze")
+	}}
+	p2 := pk.Packet{Data: []byte{
+		0x00, // pk.Boolean(false)
+		// empty
+	}}
+
+	var User1, User2 pk.Option[pk.String]
+	if err := p1.Scan(&User1); err != nil {
+		panic(err)
+	}
+	if err := p2.Scan(&User2); err != nil {
+		panic(err)
+	}
+
+	fmt.Println(User1.Has, User1.Val)
+	fmt.Println(User2.Has, User2.Val)
+
+	// Output:
+	// true Tnze
+	// false
+}

server/keepalive.go

@@ -118,7 +118,6 @@ func (k *KeepAlive) tickPlayer(c KeepAliveClient) {
 	elem, ok := k.listIndex[c]
 	if !ok {
 		panic(errors.New("keepalive: fail to tick player: client not found"))
-		return
 	}
 	if elem.Prev() == nil {
 		if !k.waitTimer.Stop() {
@@ -156,7 +155,6 @@ func keepAliveSetTimer(l *list.List, timer *time.Timer, interval time.Duration)
 		}
 	}
 	timer.Reset(interval)
-	return
 }
 
 type keepAliveItem struct {

server/login.go

@@ -64,21 +64,13 @@ func (d *MojangLoginHandler) AcceptLogin(conn *net.Conn, protocol int32) (name s
 	}
 
 	var (
-		hasPubKey   pk.Boolean
+		pubKey      pk.Option[auth.PublicKey]
-		pubKey      auth.PublicKey
+		profileUUID pk.Option[pk.UUID] // ignored
-		hasUUID     pk.Boolean
-		profileUUID pk.UUID // ignored
 	)
 	err = p.Scan(
 		(*pk.String)(&name), // decode username as pk.String
-		&hasPubKey, pk.Opt{
+		&pubKey,
-			Has:   &hasPubKey,
+		&profileUUID,
-			Field: &pubKey,
-		},
-		&hasUUID, pk.Opt{
-			Has:   &hasUUID,
-			Field: &profileUUID,
-		},
 	)
 	if err != nil {
 		return
@@ -86,12 +78,12 @@ func (d *MojangLoginHandler) AcceptLogin(conn *net.Conn, protocol int32) (name s
 
 	// auth
 	if d.OnlineMode {
-		if hasPubKey {
+		if pubKey.Has {
-			if !pubKey.Verify() {
+			if !pubKey.Val.Verify() {
 				err = LoginFailErr{reason: chat.TranslateMsg("multiplayer.disconnect.invalid_public_key_signature")}
 				return
 			}
-			profilePubKey = &pubKey
+			profilePubKey = &pubKey.Val
 		} else if d.EnforceSecureProfile {
 			err = LoginFailErr{reason: chat.TranslateMsg("multiplayer.disconnect.missing_public_key")}
 			return
@@ -99,7 +91,7 @@ func (d *MojangLoginHandler) AcceptLogin(conn *net.Conn, protocol int32) (name s
 
 		var resp *auth.Resp
 		// Auth, Encrypt
-		resp, err = auth.Encrypt(conn, name, pubKey.PubKey)
+		resp, err = auth.Encrypt(conn, name, pubKey.Val.PubKey)
 		if err != nil {
 			return
 		}