Fix overwrite of existing cookiejar.

libkiwi.go

@@ -21,25 +21,25 @@ type KF struct {
 }
 
 // Supply your own http.Client to route through any proxies.
-func NewKF(hc http.Client, host *url.URL) (*KF, error) {
+func NewKF(hc http.Client, host *url.URL) (KF, error) {
 	u, err := url.Parse(fmt.Sprintf("https://%s", host.Hostname()))
 	if err != nil {
-		return nil, err
+		return KF{}, err
 	}
 
-	jar, err := cookiejar.New(nil)
-	if err != nil {
-		return nil, err
+	if hc.Jar == nil {
+		jar, err := cookiejar.New(nil)
+		if err != nil {
+			return KF{}, err
+		}
+
+		hc.Jar = jar
 	}
 
-	hc.Jar = jar
-
-	kf := &KF{
+	return KF{
 		client: hc,
 		domain: u,
-	}
-
-	return kf, nil
+	}, nil
 }
 
 type User struct {