[wip] Update Join Game packet

Author: raqbit

go.mod

@@ -6,5 +6,6 @@ require (
 	github.com/dave/jennifer v1.4.1
 	github.com/google/uuid v1.1.1
 	github.com/stretchr/testify v1.7.0
+	github.com/yuin/stagparser v0.0.0-20181218160030-e10a81132760
 	golang.org/x/tools v0.1.0
 )

go.sum

@@ -10,6 +10,8 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+github.com/yuin/stagparser v0.0.0-20181218160030-e10a81132760 h1:i+m5+M2renk/OmDHvzRjlBQXm+5X6WR6xPjWfHNzvcM=
+github.com/yuin/stagparser v0.0.0-20181218160030-e10a81132760/go.mod h1:+qbo7cNcx8dT/77C41x4MZbasDrLuUDI/04ZGR/7IqM=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=

packet/client_settings.go

@@ -10,7 +10,7 @@ import (
 const ClientSettingsPacketID int32 = 0x05
 
 type ClientSettingsPacket struct {
-	Lang               enc.String
+	Locale             enc.String `pkt:"strLen(16)"`
 	ViewDistance       enc.Byte
 	ChatVisibility     enc.VarInt
 	EnableChatColors   enc.Bool

packet/client_settings_gen.go

@@ -12,7 +12,7 @@ const HandshakePacketID int32 = 0x00
 // https://wiki.vg/Protocol#Handshake
 type HandshakePacket struct {
 	ProtoVer   enc.VarInt
-	ServerAddr enc.String
+	ServerAddr enc.String `pkt:"strLen(255)"`
 	ServerPort enc.UnsignedShort
 	NextState  types.ConnectionState
 }

packet/handshake.go

@@ -5,20 +5,27 @@ import (
 	"github.com/Raqbit/mcproto/types"
 )
 
-//go:generate go run ../tools/genpacket/genpacket.go -packet=JoinGamePacket -output=join_game_gen.go
+//go:generate go run ../tools/genpacket -packet=JoinGamePacket -output=join_game_gen.go
 
 const JoinGamePacketID int32 = 0x26
 
 type JoinGamePacket struct {
-	PlayerID            enc.Int
-	GameMode            enc.UnsignedByte
-	Dimension           enc.Int
+	PlayerID         enc.Int
+	IsHardcore       enc.Bool
+	GameMode         enc.UnsignedByte
+	PreviousGameMode enc.Byte
+	WorldCount       enc.VarInt
+	WorldNames       []types.Identifier `pkt:"lenFrom(WorldCount)"`
+	//DimensionCodec nbt.Something // TODO
+	//Dimension nbt.Something // TODO
+	WorldName           types.Identifier
 	HashedSeed          enc.Long
 	MaxPlayers          enc.UnsignedByte
-	LevelType           enc.String `len:"16"`
 	ViewDistance        enc.VarInt
-	ReducedDebug        enc.Bool
+	ReducedDebugInfo    enc.Bool
 	EnableRespawnScreen enc.Bool
+	IsDebug             enc.Bool
+	IsFlat              enc.Bool
 }
 
 func (*JoinGamePacket) String() string {

packet/join_game.go

@@ -11,7 +11,7 @@ const LoginStartPacketID int32 = 0x00
 
 // https://wiki.vg/Protocol#Login_Start
 type LoginStartPacket struct {
-	Name enc.String
+	Name enc.String `pkt:"strLen(16)"`
 }
 
 func (*LoginStartPacket) Info() PacketInfo {

packet/join_game_gen.go

@@ -12,7 +12,7 @@ const LoginSuccessPacketID = 0x02
 // https://wiki.vg/Protocol#Login_Success
 type LoginSuccessPacket struct {
 	UUID     enc.UUID
-	Username enc.String
+	Username enc.String `pkt:"strLen(16)"`
 }
 
 func (*LoginSuccessPacket) Info() PacketInfo {

packet/login_start.go

@@ -20,6 +20,7 @@ const (
 	WriterName    = "w"
 	ReaderName    = "r"
 	Directory     = "."
+	SliceItemName = "v"
 )
 
 var (
@@ -124,14 +125,19 @@ func (g *Generator) generate(typeName string) error {
 		return fmt.Errorf("%s is not a struct type", typeName)
 	}
 
-	name := obj.Name()
-	idName := strings.ToLower(name[:1])
+	receiverName := strings.ToLower(typeName[:1])
+
+	//_, err := parsePacket(struc, typeName)
+
+	//if err != nil {
+	//	return fmt.Errorf("could not parse packet struct %s: %w", typeName, err)
+	//}
 
 	g.file.
 		Func().
 		Params(
-			jen.Id(idName).
-				Id("*" + obj.Name()),
+			jen.Id(receiverName).
+				Id("*" + typeName),
 		).
 		Id(FuncMarshal).
 		Params(jen.Id(WriterName).Qual("io", "Writer")).
@@ -143,18 +149,13 @@ func (g *Generator) generate(typeName string) error {
 
 			for i := 0; i < struc.NumFields(); i++ {
 				field := struc.Field(i)
+				_, isSlice := field.Type().(*types.Slice)
 
-				group.If(
-					jen.Err().
-						Op("=").
-						Id(idName).
-						Dot(field.Name()).
-						Dot("Write").
-						Call(
-							jen.Id(WriterName),
-						),
-					jen.Err().Op("!=").Nil(),
-				).Block(jen.Return().Err())
+				if isSlice {
+					genSliceFieldWrite(group, receiverName, field)
+				} else {
+					genFieldWrite(group, receiverName, field)
+				}
 			}
 
 			group.Return().Nil()
@@ -163,7 +164,7 @@ func (g *Generator) generate(typeName string) error {
 	g.file.
 		Func().
 		Params(
-			jen.Id(idName).
+			jen.Id(receiverName).
 				Id("*" + obj.Name()),
 		).
 		Id(FuncUnmarshal).
@@ -177,17 +178,7 @@ func (g *Generator) generate(typeName string) error {
 			for i := 0; i < struc.NumFields(); i++ {
 				field := struc.Field(i)
 
-				group.If(
-					jen.Err().
-						Op("=").
-						Id(idName).
-						Dot(field.Name()).
-						Dot("Read").
-						Call(
-							jen.Id(ReaderName),
-						),
-					jen.Err().Op("!=").Nil(),
-				).Block(jen.Return().Err())
+				genFieldRead(group, receiverName, field)
 			}
 
 			group.Return().Nil()
@@ -196,6 +187,46 @@ func (g *Generator) generate(typeName string) error {
 	return nil
 }
 
-func unqualified(*types.Package) string {
-	return ""
+func genSliceFieldWrite(group *jen.Group, receiverName string, field *types.Var) {
+	group.For(jen.List(jen.Id("_"), jen.Id(SliceItemName)).
+		Op(":=").
+		Range().
+		Id(receiverName).
+		Dot(field.Name()).
+		BlockFunc(func(group *jen.Group) {
+			group.If(jen.Err().Op("=").Id(SliceItemName).Dot("Write").
+				Call(
+					jen.Id(WriterName),
+				),
+				jen.Err().Op("!=").Nil(),
+			).Block(jen.Return().Err())
+		}))
+}
+
+func genFieldWrite(group *jen.Group, receiverName string, field *types.Var) {
+	group.If(
+		jen.Err().
+			Op("=").
+			Id(receiverName).
+			Dot(field.Name()).
+			Dot("Write").
+			Call(
+				jen.Id(WriterName),
+			),
+		jen.Err().Op("!=").Nil(),
+	).Block(jen.Return().Err())
+}
+
+func genFieldRead(group *jen.Group, receiverName string, field *types.Var) {
+	group.If(
+		jen.Err().
+			Op("=").
+			Id(receiverName).
+			Dot(field.Name()).
+			Dot("Read").
+			Call(
+				jen.Id(ReaderName),
+			),
+		jen.Err().Op("!=").Nil(),
+	).Block(jen.Return().Err())
 }

packet/login_success.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"fmt"
+	"github.com/yuin/stagparser"
+	"go/types"
+	"strings"
+)
+
+type param struct {
+	name  string
+	value interface{}
+}
+
+type field struct {
+	name   string
+	params []param
+}
+
+type packet struct {
+	name   string
+	fields []field
+}
+
+func (p *packet) String() string {
+	sb := strings.Builder{}
+	sb.WriteString(fmt.Sprintf("packet %s {\n", p.name))
+	for _, fld := range p.fields {
+		sb.WriteString(fmt.Sprintf("\t%s (", fld.name))
+		for _, prm := range fld.params {
+			sb.WriteString(fmt.Sprintf("%s=%s,", prm.name, prm.value))
+		}
+		sb.WriteString(")")
+	}
+	sb.WriteString("}\n")
+
+	return sb.String()
+}
+
+func parsePacket(packetType *types.Struct, structName string) (packet, error) {
+	fields := make([]field, packetType.NumFields())
+
+	for i := 0; i < packetType.NumFields(); i++ {
+		f := packetType.Field(i)
+		t := packetType.Tag(i)
+
+		// TODO: stagparser expects us to give it one "value" of a struct tag (`key:"value"`)
+		// TODO: this is hard to do as the parser for it is only really present in reflect, not AST.
+		// TODO: a custom tag parser will probably have to be implemented
+		defs, err := stagparser.ParseTag(t, structName)
+
+		if err != nil {
+			return packet{}, fmt.Errorf("could not parse struct tag for field %s: %w", f.Name(), err)
+		}
+
+		params := make([]param, len(defs))
+
+		for j, def := range defs {
+			for name, value := range def.Attributes() {
+				params[j] = param{
+					name:  name,
+					value: value,
+				}
+			}
+		}
+
+		fields[i] = field{
+			name:   f.Name(),
+			params: make([]param, 0),
+		}
+
+	}
+
+	return packet{
+		name:   structName,
+		fields: fields,
+	}, nil
+}