Use peerID type more, and make its Stringer output nicer

client.go

@@ -43,7 +43,7 @@ type Client struct {
 	config Config
 
 	halfOpenLimit  int
-	peerID         [20]byte
+	peerID         peerID
 	defaultStorage *storage.Client
 	onClose        []func()
 	tcpListener    net.Listener

connection.go

@@ -73,7 +73,7 @@ type connection struct {
 	sentHaves        []bool
 
 	// Stuff controlled by the remote peer.
-	PeerID             [20]byte
+	PeerID             peerID
 	PeerInterested     bool
 	PeerChoked         bool
 	PeerRequests       map[request]struct{}
@@ -194,7 +194,7 @@ func (cn *connection) String() string {
 
 func (cn *connection) WriteStatus(w io.Writer, t *Torrent) {
 	// \t isn't preserved in <pre> blocks?
-	fmt.Fprintf(w, "%+q: %s-%s\n", cn.PeerID, cn.localAddr(), cn.remoteAddr())
+	fmt.Fprintf(w, "%-40s: %s-%s\n", cn.PeerID, cn.localAddr(), cn.remoteAddr())
 	fmt.Fprintf(w, "    last msg: %s, connected: %s, last useful chunk: %s\n",
 		eventAgeString(cn.lastMessageReceived),
 		eventAgeString(cn.completedHandshake),

handshake.go

@@ -36,7 +36,6 @@ func handshakeWriter(w io.Writer, bb <-chan []byte, done chan<- error) {
 
 type (
 	peerExtensionBytes [8]byte
-	peerID             [20]byte
 )
 
 func (pex peerExtensionBytes) SupportsExtended() bool {

peerid.go

@@ -0,0 +1,14 @@
+package torrent
+
+import (
+	"encoding/hex"
+)
+
+type peerID [20]byte
+
+func (me peerID) String() string {
+	if me[0] == '-' && me[7] == '-' {
+		return string(me[:8]) + hex.EncodeToString(me[8:])
+	}
+	return hex.EncodeToString(me[:])
+}

peerid_test.go

@@ -0,0 +1,22 @@
+package torrent
+
+import (
+	"testing"
+
+	"github.com/anacrolix/missinggo"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPeerIdString(t *testing.T) {
+	for _, _case := range []struct {
+		id string
+		s  string
+	}{
+		{"\x1cNJ}\x9c\xc7\xc4o\x94<\x9b\x8c\xc2!I\x1c\a\xec\x98n", "1c4e4a7d9cc7c46f943c9b8cc221491c07ec986e"},
+		{"-FD51W\xe4-LaZMk0N8ZLA7", "-FD51W\xe4-4c615a4d6b304e385a4c4137"},
+	} {
+		var pi peerID
+		missinggo.CopyExact(&pi, _case.id)
+		assert.EqualValues(t, _case.s, pi.String())
+	}
+}