Refactor adapter

adapter/handler.go

@@ -0,0 +1,117 @@
+package adapter
+
+import (
+	"context"
+	"net"
+
+	"github.com/sagernet/sing/common/buf"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+type (
+	ConnectionHandler interface {
+		NewConnection(ctx context.Context, conn net.Conn, metadata InboundContext) error
+	}
+	PacketHandler interface {
+		NewPacket(ctx context.Context, conn N.PacketConn, buffer *buf.Buffer, metadata InboundContext) error
+	}
+	PacketConnectionHandler interface {
+		NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata InboundContext) error
+	}
+	UpstreamHandlerAdapter interface {
+		N.TCPConnectionHandler
+		N.UDPConnectionHandler
+		E.Handler
+	}
+	ConnectionHandlerFunc       = func(ctx context.Context, conn net.Conn, metadata InboundContext) error
+	PacketConnectionHandlerFunc = func(ctx context.Context, conn N.PacketConn, metadata InboundContext) error
+)
+
+func NewUpstreamHandler(
+	metadata InboundContext,
+	connectionHandler ConnectionHandlerFunc,
+	packetHandler PacketConnectionHandlerFunc,
+	errorHandler E.Handler,
+) UpstreamHandlerAdapter {
+	return &myUpstreamHandlerWrapper{
+		metadata:          metadata,
+		connectionHandler: connectionHandler,
+		packetHandler:     packetHandler,
+		errorHandler:      errorHandler,
+	}
+}
+
+var _ UpstreamHandlerAdapter = (*myUpstreamHandlerWrapper)(nil)
+
+type myUpstreamHandlerWrapper struct {
+	metadata          InboundContext
+	connectionHandler ConnectionHandlerFunc
+	packetHandler     PacketConnectionHandlerFunc
+	errorHandler      E.Handler
+}
+
+func (w *myUpstreamHandlerWrapper) NewConnection(ctx context.Context, conn net.Conn, metadata M.Metadata) error {
+	w.metadata.Destination = metadata.Destination
+	return w.connectionHandler(ctx, conn, w.metadata)
+}
+
+func (w *myUpstreamHandlerWrapper) NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata M.Metadata) error {
+	w.metadata.Destination = metadata.Destination
+	return w.packetHandler(ctx, conn, w.metadata)
+}
+
+func (w *myUpstreamHandlerWrapper) NewError(ctx context.Context, err error) {
+	w.errorHandler.NewError(ctx, err)
+}
+
+var myContextType = (*MetadataContext)(nil)
+
+type MetadataContext struct {
+	context.Context
+	Metadata InboundContext
+}
+
+func (c *MetadataContext) Value(key any) any {
+	if key == myContextType {
+		return c
+	}
+	return c.Context.Value(key)
+}
+
+type myUpstreamContextHandlerWrapper struct {
+	connectionHandler ConnectionHandlerFunc
+	packetHandler     PacketConnectionHandlerFunc
+	errorHandler      E.Handler
+}
+
+func NewUpstreamContextHandler(
+	connectionHandler ConnectionHandlerFunc,
+	packetHandler PacketConnectionHandlerFunc,
+	errorHandler E.Handler,
+) UpstreamHandlerAdapter {
+	return &myUpstreamContextHandlerWrapper{
+		connectionHandler: connectionHandler,
+		packetHandler:     packetHandler,
+		errorHandler:      errorHandler,
+	}
+}
+
+func (w *myUpstreamContextHandlerWrapper) NewConnection(ctx context.Context, conn net.Conn, metadata M.Metadata) error {
+	myCtx := ctx.Value(myContextType).(*MetadataContext)
+	ctx = myCtx.Context
+	myCtx.Metadata.Destination = metadata.Destination
+	return w.connectionHandler(ctx, conn, myCtx.Metadata)
+}
+
+func (w *myUpstreamContextHandlerWrapper) NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata M.Metadata) error {
+	myCtx := ctx.Value(myContextType).(*MetadataContext)
+	ctx = myCtx.Context
+	myCtx.Metadata.Destination = metadata.Destination
+	return w.packetHandler(ctx, conn, myCtx.Metadata)
+}
+
+func (w *myUpstreamContextHandlerWrapper) NewError(ctx context.Context, err error) {
+	w.errorHandler.NewError(ctx, err)
+}