You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: old_base36.rs
    path of file: ./repos/CYFS/src/component/cyfs-chunk-cache/src
    
    the code of the file until where you have to start completion: use cyfs_base::*;

use std::path::{Path, PathBuf};

trait ToOldBase36 {
    fn to_old_base36(&self) -> String;
}

const ALPHABET: &[u8] = b"0123456789abcdefghijklmnoqprstuvwxyz";

impl ToOldBase36 for [u8] {
    fn to_old_base36(&self) -> String {
        base_x::encode(ALPHABET, self)
    }
}

pub(super) struct ChunkStorageUpgrade {
    root: PathBuf,
}

impl ChunkStorageUpgrade {
    pub fn new(root: PathBuf) -> Self {
        Self { root }
    }

    fn get_old_full_path(&self, chunk_id: &ChunkId) -> PathBuf {
        let hash_str = chunk_id.as_slice().to_old_base36();
        let len = 3;

        let (tmp, first) = hash_str.split_at(hash_str.len() - len);
        let (left, second) = tmp.s
    
    pub fn try_update(&self, dest: &Path, chunk_id: &ChunkId) -> bool {
        let old_path = self.get_old_full_path(chunk_id);
        if !old_path.exists() {
            return false;
        }

        log::info!(
            "will update chunk file for error base36's bug! chunk={}, {} -> {}",
            chunk_id,
            old_path.display(),
            dest.display()
        );

        let dir = dest.parent().unwrap();
        if !dir.exists() {
            if let Err(e) = std::fs::create_dir_all(&dir) {
                log::error!(
                    "create dir for chunk error! path={}, {}",
                    dir.display(),
                    e
                );
            }
        }

        if let Err(e) = std::fs::rename(&old_path, &dest) {
            log::error!(
                "move chunk file error! object={}, {} -> {}, {}",
                chunk_id,
                old_path.display(),
                dest.display(),
                e,
            );
            return false;
        }

        true
    }