crashing on saves

[DevinBayly]

There are two separate issues that cause crashes when saving a file with vixi.

1

event_controller/view.rs line 48

    pub fn lines_availables_after(&self, start: u32) -> u32 {
        (self.lines.len() as u32) - start
    }

start is frequently larger than what lines len gets set to when working with a file over 100 lines

2

same file line 172.

    pub fn update_buffer(&mut self, operations: Vec<Operation>) {
      .
      .
      .
      .

                        let old_buffer = &self.buffer.lines[old_idx + i];
                        new_buffer.lines.push(Line {
                            raw: old_buffer.raw.clone(),
                            ln: operation.ln.map(|ln| ln + i),
                            is_dirty,
                        });
                        new_idx += 1;
                    }

                    old_idx += operation.n;
                }

indexing into buffer.lines is often at a value too high for the actual length of the vector.

These issues seem related to something elsewhere that prevents the buffer from having an accurate count of its lines.