Macro safe_lock 

macro_rules! safe_lock {
    (clone: $lock_name:expr) => { ... };
    (set: $lock_name:expr, $value:expr) => { ... };
    (mem_take: $lock_name:expr) => { ... };
    (mem_take: $lock_name:expr, $field_name:ident) => { ... };
    (mem_replace: $lock_name:expr, $value:expr) => { ... };
    (mem_replace: $lock_name:expr, $field_name:ident, $value:expr) => { ... };
}