Fix XMPP logger consistency

- Rename socketProxy to StreamLogger
- Ensure client send traffic through the logger

stream_logger.go

@@ -0,0 +1,53 @@
+package xmpp
+
+import (
+	"io"
+	"os"
+)
+
+// Mediated Read / Write on socket
+// Used if logFile from Config is not nil
+type streamLogger struct {
+	socket  io.ReadWriter // Actual connection
+	logFile *os.File
+}
+
+func newStreamLogger(conn io.ReadWriter, logFile *os.File) io.ReadWriter {
+	if logFile == nil {
+		return conn
+	} else {
+		return &streamLogger{conn, logFile}
+	}
+}
+
+func (sp *streamLogger) Read(p []byte) (n int, err error) {
+	n, err = sp.socket.Read(p)
+	if n > 0 {
+		sp.logFile.Write([]byte("RECV:\n")) // Prefix
+		if n, err := sp.logFile.Write(p[:n]); err != nil {
+			return n, err
+		}
+		sp.logFile.Write([]byte("\n\n")) // Separator
+	}
+	return
+}
+
+func (sp *streamLogger) Write(p []byte) (n int, err error) {
+	sp.logFile.Write([]byte("SEND:\n")) // Prefix
+	for _, w := range []io.Writer{sp.socket, sp.logFile} {
+		n, err = w.Write(p)
+		if err != nil {
+			return
+		}
+		if n != len(p) {
+			err = io.ErrShortWrite
+			return
+		}
+	}
+	sp.logFile.Write([]byte("\n\n")) // Separator
+	return len(p), nil
+}
+
+/*
+TODO: Make RECV, SEND prefixes +
+*/