Handling basic unrecoverable errors

Fix #43

conn_error.go

@@ -0,0 +1,33 @@
+package xmpp // import "gosrc.io/xmpp"
+
+import (
+	"fmt"
+
+	"golang.org/x/xerrors"
+)
+
+type ConnError struct {
+	frame xerrors.Frame
+	err   error
+	// Permanent will be true if error is not recoverable
+	Permanent bool
+}
+
+func NewConnError(err error, permanent bool) ConnError {
+	return ConnError{err: err, frame: xerrors.Caller(1), Permanent: permanent}
+}
+
+func (e ConnError) Format(s fmt.State, verb rune) {
+	xerrors.FormatError(e, s, verb)
+}
+
+func (e ConnError) FormatError(p xerrors.Printer) error {
+	e.frame.Format(p)
+	return e.err
+}
+
+func (e ConnError) Error() string {
+	return fmt.Sprint(e)
+}
+
+func (e ConnError) Unwrap() error { return e.err }