First implementation

vendor/github.com/eclipse/paho.mqtt.golang/trace.go

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2013 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Seth Hoenig
+ *    Allan Stockdill-Mander
+ *    Mike Robertson
+ */
+
+package mqtt
+
+type (
+	// Logger interface allows implementations to provide to this package any
+	// object that implements the methods defined in it.
+	Logger interface {
+		Println(v ...interface{})
+		Printf(format string, v ...interface{})
+	}
+
+	// NOOPLogger implements the logger that does not perform any operation
+	// by default. This allows us to efficiently discard the unwanted messages.
+	NOOPLogger struct{}
+)
+
+func (NOOPLogger) Println(v ...interface{}) {}
+func (NOOPLogger) Printf(format string, v ...interface{}) {}
+
+// Internal levels of library output that are initialised to not print
+// anything but can be overridden by programmer
+var (
+	ERROR    Logger = NOOPLogger{}
+	CRITICAL Logger = NOOPLogger{}
+	WARN     Logger = NOOPLogger{}
+	DEBUG    Logger = NOOPLogger{}
+)