fn update_direction()

in common/rusty_leveldb_sgx/src/merging_iter.rs [52:97]

• 40 lines of code
• 14 McCabe index (conditional complexity)

    fn update_direction(&mut self, d: Direction) {
        if self.direction == d {
            return;
        }

        let mut keybuf = vec![];
        let mut valbuf = vec![];

        if let Some((key, _)) = current_key_val(self) {
            if let Some(current) = self.current {
                match d {
                    Direction::Forward if self.direction == Direction::Reverse => {
                        self.direction = Direction::Forward;
                        for i in 0..self.iters.len() {
                            if i != current {
                                self.iters[i].seek(&key);
                                // This doesn't work if two iterators are returning the exact same
                                // keys. However, in reality, two entries will always have differing
                                // sequence numbers.
                                if self.iters[i].current(&mut keybuf, &mut valbuf) {
                                    if self.cmp.cmp(&keybuf, &key) == Ordering::Equal {
                                        self.iters[i].advance();
                                    }
                                }
                            }
                        }
                    }
                    Direction::Reverse if self.direction == Direction::Forward => {
                        self.direction = Direction::Reverse;
                        for i in 0..self.iters.len() {
                            if i != current {
                                self.iters[i].seek(&key);
                                if self.iters[i].valid() {
                                    self.iters[i].prev();
                                } else {
                                    // seek to last.
                                    while self.iters[i].advance() {}
                                }
                            }
                        }
                    }
                    _ => {}
                }
            }
        }
    }