fn find_empty(&mut self) -> usize {
        if let Some(e) = self.empty_head {
            self.empty_head = self.entries[e].as_empty_mut().next_empty;
            return e;
        }

        self.entries
            .push(CacheEntry::Empty(EmptyEntry { next_empty: None }));
        self.entries.len() - 1
    }
/// Find an available empty index, or make one if necessary.
Find an available empty index, or make one if necessary.
Find an available empty index or make one if necessary .
fn find_empty(&mut self) -> usize {
        if let Some(e) = self.empty_head {
            self.empty_head = self.entries[e].as_empty_mut().next_empty;
            return e;
        }
        self.entries
            .push(CacheEntry::Empty(EmptyEntry { next_empty: None }));
        self.entries.len() - 1
    }
fn find_empty ( & mut self ) -> usize { if let Some ( e ) = self . empty_head { self . empty_head = self . entries [ e ] . as_empty_mut ( ) . next_empty ; return e ; } self . entries . push ( CacheEntry :: Empty ( EmptyEntry { next_empty : None } ) ) ; self . entries . len ( ) - 1 }
Find an available empty index, or make one if necessary.
Find an available empty index or make one if necessary .
&mut self
&mut self