Replaced log.Logger parameter by interface (#20)

conn_opt.go

@@ -2,10 +2,15 @@ package jsonrpc2
 
 import (
 	"encoding/json"
-	"log"
 	"sync"
 )
 
+// Logger interface implements one method - Printf.
+// You can use the stdlib logger *log.Logger
+type Logger interface {
+	Printf(format string, v ...interface{})
+}
+
 // ConnOpt is the type of function that can be passed to NewConn to
 // customize the Conn before it is created.
 type ConnOpt func(*Conn)
@@ -24,7 +29,7 @@ func OnSend(f func(*Request, *Response)) ConnOpt {
 
 // LogMessages causes all messages sent and received on conn to be
 // logged using the provided logger.
-func LogMessages(log *log.Logger) ConnOpt {
+func LogMessages(log Logger) ConnOpt {
 	return func(c *Conn) {
 		// Remember reqs we have received so we can helpfully show the
 		// request method in OnSend for responses.