Tidy up the Dialer interface

dialer.go

@@ -3,43 +3,32 @@ package torrent
 import (
 	"context"
 	"net"
-
-	"github.com/anacrolix/missinggo/perf"
 )
 
+// Dialers have the network locked in.
 type Dialer interface {
 	Dial(_ context.Context, addr string) (net.Conn, error)
 	DialerNetwork() string
 }
 
-type NetDialer struct {
-	Network string
-	Dialer  net.Dialer
+// An interface to ease wrapping dialers that explicitly include a network parameter.
+type DialContexter interface {
+	DialContext(ctx context.Context, network, addr string) (net.Conn, error)
 }
 
-func (me NetDialer) DialerNetwork() string {
+// Used by wrappers of standard library network types.
+var DefaultNetDialer = &net.Dialer{}
+
+// Adapts a DialContexter to the Dial interface in this package.
+type NetworkDialer struct {
+	Network string
+	Dialer  DialContexter
+}
+
+func (me NetworkDialer) DialerNetwork() string {
 	return me.Network
 }
 
-func (me NetDialer) Dial(ctx context.Context, addr string) (_ net.Conn, err error) {
-	defer perf.ScopeTimerErr(&err)()
+func (me NetworkDialer) Dial(ctx context.Context, addr string) (_ net.Conn, err error) {
 	return me.Dialer.DialContext(ctx, me.Network, addr)
 }
-
-func (me NetDialer) LocalAddr() net.Addr {
-	return netDialerLocalAddr{me.Network, me.Dialer.LocalAddr}
-}
-
-type netDialerLocalAddr struct {
-	network string
-	addr    net.Addr
-}
-
-func (me netDialerLocalAddr) Network() string { return me.network }
-
-func (me netDialerLocalAddr) String() string {
-	if me.addr == nil {
-		return ""
-	}
-	return me.addr.String()
-}

socket.go

@@ -39,15 +39,16 @@ func listenTcp(network, address string) (s socket, err error) {
 	l, err := net.Listen(network, address)
 	return tcpSocket{
 		Listener: l,
-		NetDialer: NetDialer{
+		NetworkDialer: NetworkDialer{
 			Network: network,
+			Dialer:  DefaultNetDialer,
 		},
 	}, err
 }
 
 type tcpSocket struct {
 	net.Listener
-	NetDialer
+	NetworkDialer
 }
 
 func listenAll(networks []network, getHost func(string) string, port int, f firewallCallback) ([]socket, error) {

test/unix_test.go

@@ -24,7 +24,7 @@ func TestUnixConns(t *testing.T) {
 			cfg.Debug = true
 		},
 		Client: func(cl *torrent.Client) {
-			cl.AddDialer(torrent.NetDialer{Network: "unix"})
+			cl.AddDialer(torrent.NetworkDialer{Network: "unix", Dialer: torrent.DefaultNetDialer})
 			l, err := net.Listen("unix", filepath.Join(t.TempDir(), "socket"))
 			if err != nil {
 				panic(err)