Add multiLess and use it for worseConn

multiless.go

@@ -0,0 +1,46 @@
+package torrent
+
+func strictCmp(same, less bool) cmper {
+	return func() (bool, bool) { return same, less }
+}
+
+type (
+	cmper     func() (same, less bool)
+	multiLess struct {
+		ok   bool
+		less bool
+	}
+)
+
+func (me *multiLess) Final() bool {
+	if !me.ok {
+		panic("undetermined")
+	}
+	return me.less
+}
+
+func (me *multiLess) FinalOk() (left, ok bool) {
+	return me.less, me.ok
+}
+
+func (me *multiLess) Next(f cmper) {
+	if me.ok {
+		return
+	}
+	same, less := f()
+	if same {
+		return
+	}
+	me.ok, me.less = true, less
+}
+
+func (me *multiLess) StrictNext(same, less bool) {
+	if same {
+		return
+	}
+	me.ok, me.less = true, less
+}
+
+func (me *multiLess) NextBool(l, r bool) {
+	me.StrictNext(l == r, l)
+}

worst_conns.go

@@ -3,13 +3,15 @@ package torrent
 import "container/heap"
 
 func worseConn(l, r *connection) bool {
-	if l.useful() != r.useful() {
-		return r.useful()
-	}
-	if !l.lastHelpful().Equal(r.lastHelpful()) {
-		return l.lastHelpful().Before(r.lastHelpful())
-	}
-	return l.completedHandshake.Before(r.completedHandshake)
+	var ml multiLess
+	ml.NextBool(!l.useful(), !r.useful())
+	ml.StrictNext(
+		l.lastHelpful().Equal(r.lastHelpful()),
+		l.lastHelpful().Before(r.lastHelpful()))
+	ml.StrictNext(
+		l.completedHandshake.Equal(r.completedHandshake),
+		l.completedHandshake.Before(r.completedHandshake))
+	return ml.Final()
 }
 
 type worseConnSlice struct {