mox!

smtpserver/limitwriter.go

@@ -0,0 +1,25 @@
+package smtpserver
+
+import (
+	"errors"
+	"io"
+)
+
+var errMessageTooLarge = errors.New("maximum message size exceeded")
+
+type limitWriter struct {
+	maxSize int64
+	w       io.Writer
+	written int64
+}
+
+func (w *limitWriter) Write(buf []byte) (int, error) {
+	if w.written+int64(len(buf)) > w.maxSize {
+		return 0, errMessageTooLarge
+	}
+	n, err := w.w.Write(buf)
+	if n > 0 {
+		w.written += int64(n)
+	}
+	return n, err
+}