Transaktions-Rollback-Ausführung mit benutzerdefinierten Scope-Guards

pub struct RollbackGuard<'a, T: Clone> {
    value_ref: &'a mut T,
    backup: T,
    dismissed: bool,
}
 
impl<'a, T: Clone> RollbackGuard<'a, T> {
    pub fn new(value_ref: &'a mut T) -> Self {
        let backup = value_ref.clone();
        Self { value_ref, backup, dismissed: false }
    }
    pub fn commit(mut self) {
        self.dismissed = true;
    }
}
 
impl<'a, T: Clone> Drop for RollbackGuard<'a, T> {
    fn drop(&mut self) {
        if !self.dismissed {
            *self.value_ref = self.backup.clone();
        }
    }
}