yess

proto/connection.go

@@ -0,0 +1,154 @@
+package proto
+
+import (
+	"bytes"
+	"compress/zlib"
+	"errors"
+	"io"
+	"net"
+
+	"github.com/admin-else/strom/event"
+	"github.com/admin-else/strom/proto_base"
+	"github.com/admin-else/strom/proto_generated"
+)
+
+var BadPacketTypeError = errors.New("bad packet type")
+
+// UnCodablePacket represents a packet that could not be decoded due to proto_generated not supporting all packets.
+type UnCodablePacket struct {
+	Err     error
+	Partial any
+	Data    []byte
+}
+
+type Conn struct {
+	net.Conn
+	R                                io.Reader
+	W                                io.Writer
+	CompressionThreshold             int32
+	State                            proto_base.State
+	Actor                            proto_base.Actor
+	Version                          string
+	DontDecodePacketsWithoutHandlers bool
+}
+
+func (c *Conn) Send(packet any) (err error) {
+	var rawPacketBytes []byte
+	switch packet := packet.(type) {
+	case UnCodablePacket:
+		rawPacketBytes = packet.Data
+	default:
+		packetIdentifier := proto_generated.TypeToPacketIdentifier(c.Version, c.Actor.SendDirection(), c.State, packet)
+		if packetIdentifier == "" {
+			err = BadPacketTypeError
+			return
+		}
+		rawPacketBuffer := bytes.NewBuffer(nil)
+		err = proto_generated.EncodePacket(c.Version, c.Actor.SendDirection(), c.State, packetIdentifier, packet, rawPacketBuffer)
+		if err != nil {
+			return
+		}
+		rawPacketBytes = rawPacketBuffer.Bytes()
+	}
+	var packetBytes []byte
+	if c.CompressionThreshold > 0 {
+		packetBuffer := bytes.NewBuffer(nil)
+		if int32(len(packetBytes)) >= c.CompressionThreshold {
+			err = proto_base.VarInt(len(packetBytes)).Encode(packetBuffer)
+			if err != nil {
+				return
+			}
+			_, err = zlib.NewWriter(packetBuffer).Write(rawPacketBytes)
+			if err != nil {
+				return
+			}
+		} else {
+			err = proto_base.VarInt(0).Encode(packetBuffer)
+			if err != nil {
+				return
+			}
+			_, err = packetBuffer.Write(rawPacketBytes)
+			if err != nil {
+				return
+			}
+		}
+		packetBytes = packetBuffer.Bytes()
+	} else {
+		packetBytes = rawPacketBytes
+	}
+	err = proto_base.VarInt(len(packetBytes)).Encode(c.W)
+	if err != nil {
+		return
+	}
+	_, err = c.W.Write(packetBytes)
+	return
+}
+
+func (c *Conn) Receive() (packet any, err error) {
+	var rawPacketLen proto_base.VarInt
+	rawPacketLen, err = rawPacketLen.Decode(c.R)
+	if err != nil {
+		return
+	}
+	rawPacketBytes, err := io.ReadAll(io.LimitReader(c.R, int64(rawPacketLen)))
+	if err != nil {
+		return
+	}
+	rawPacketBuffer := bytes.NewBuffer(rawPacketBytes)
+	var packetBytes []byte
+	if c.CompressionThreshold > 0 {
+		var packetLen proto_base.VarInt
+		packetLen, err = packetLen.Decode(rawPacketBuffer)
+		if err != nil {
+			return
+		}
+		if packetLen == 0 {
+			packetBytes, err = io.ReadAll(rawPacketBuffer)
+			if err != nil {
+				return
+			}
+		} else {
+			var zReader io.ReadCloser
+			zReader, err = zlib.NewReader(rawPacketBuffer)
+			if err != nil {
+				return
+			}
+			defer zReader.Close()
+			packetBytes, err = io.ReadAll(zReader)
+			if err != nil {
+				return
+			}
+		}
+	} else {
+		packetBytes = rawPacketBytes
+	}
+	packetBuff := bytes.NewBuffer(packetBytes)
+	packet, err = proto_generated.DecodePacket(c.Version, c.Actor.ReceiveDirection(), c.State, packetBuff)
+	if err != nil {
+		packet = UnCodablePacket{Err: err, Data: packetBytes, Partial: packet}
+		err = nil
+	}
+	return
+}
+
+func (c *Conn) Start(inst event.HandlerInst) (err error) {
+	_ = *c // exit early on nil connection
+	handlers := event.FindHandlers(inst)
+	err = event.Fire(inst, event.OnStart{}, handlers)
+	for err == nil {
+		var packet any
+		packet, err = c.Receive()
+		if err != nil {
+			return
+		}
+		err = event.Fire(inst, packet, handlers)
+		if err != nil {
+			break
+		}
+		err = event.Fire(inst, event.OnLoopCycle{}, handlers)
+	}
+	if errors.Is(err, event.HandlerDone) {
+		err = nil
+	}
+	return
+}