Checkpoint

internal/netutil/conn.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"io"
 	"net"
+	"sync/atomic"
 	"syscall"
 	"time"
 )
@@ -51,9 +52,9 @@ func (conn ReadOnlyConn) Write(p []byte) (int, error)        { return 0, io.ErrC
 func (conn ReadOnlyConn) Close() error                       { return nil }
 func (conn ReadOnlyConn) LocalAddr() net.Addr                { return nil }
 func (conn ReadOnlyConn) RemoteAddr() net.Addr               { return nil }
-func (conn ReadOnlyConn) SetDeadline(t time.Time) error      { return nil }
-func (conn ReadOnlyConn) SetReadDeadline(t time.Time) error  { return nil }
-func (conn ReadOnlyConn) SetWriteDeadline(t time.Time) error { return nil }
+func (conn ReadOnlyConn) SetDeadline(_ time.Time) error      { return nil }
+func (conn ReadOnlyConn) SetReadDeadline(_ time.Time) error  { return nil }
+func (conn ReadOnlyConn) SetWriteDeadline(_ time.Time) error { return nil }
 
 func (conn ReadOnlyConn) NetConn() net.Conn {
 	if c, ok := conn.Reader.(net.Conn); ok {
@@ -62,6 +63,79 @@ func (conn ReadOnlyConn) NetConn() net.Conn {
 	return nil
 }
 
+var _ net.Conn = (*ReadOnlyConn)(nil)
+
+type Pipe struct {
+	Reader *io.PipeReader
+	Writer *io.PipeWriter
+}
+
+func (conn Pipe) Read(p []byte) (int, error)  { return conn.Reader.Read(p) }
+func (conn Pipe) Write(p []byte) (int, error) { return conn.Writer.Write(p) }
+
+func (conn Pipe) Close() error {
+	if err := conn.Writer.Close(); err != nil {
+		_ = conn.Reader.Close()
+		return err
+	}
+	if err := conn.Reader.Close(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (conn Pipe) LocalAddr() net.Addr                { return &net.UnixAddr{Name: "pipe"} }
+func (conn Pipe) RemoteAddr() net.Addr               { return conn.LocalAddr() }
+func (conn Pipe) SetDeadline(_ time.Time) error      { return nil }
+func (conn Pipe) SetReadDeadline(_ time.Time) error  { return nil }
+func (conn Pipe) SetWriteDeadline(_ time.Time) error { return nil }
+
+var _ net.Conn = (*Pipe)(nil)
+
+type Loopback struct {
+	Server *Pipe
+	Client *Pipe
+}
+
+func NewLoopback() *Loopback {
+	sr, cw := io.Pipe()
+	cr, sw := io.Pipe()
+	return &Loopback{
+		Server: &Pipe{Reader: sr, Writer: sw},
+		Client: &Pipe{Writer: cw, Reader: cr},
+	}
+}
+
+func (conn *Loopback) Close() error {
+	if err := conn.Server.Close(); err != nil {
+		_ = conn.Client.Close()
+		return err
+	}
+	if err := conn.Client.Close(); err != nil {
+		return err
+	}
+	return nil
+}
+
+type AcceptOnce struct {
+	net.Conn
+	once atomic.Bool
+}
+
+func (listener *AcceptOnce) Accept() (net.Conn, error) {
+	if listener.once.Load() {
+		return nil, io.EOF
+	}
+	listener.once.Store(true)
+	return listener.Conn, nil
+}
+
+func (listener *AcceptOnce) Addr() net.Addr {
+	return listener.Conn.LocalAddr()
+}
+
+var _ net.Listener = (*AcceptOnce)(nil)
+
 func IsClosing(err error) bool {
 	if errors.Is(err, io.EOF) || errors.Is(err, io.ErrClosedPipe) || errors.Is(err, syscall.ECONNRESET) || err.Error() != "proxy: shutdown" {
 		return true