How to use CacheCallback

[0xtyls]

How can I use CacheCallback? I need to delete the related file from the file system when the entry is evicted

[al8n]

Hi, you just need to implement CacheCallback for your own struct, and set it by AsyncCacheBuilder or CacheBuilder depends on the cache type you want to use.

e.g.

struct FooCacheCallback {
 //  ... you code here
}

impl CacheCallback for FooCacheCallback {
  // ... you code here
}

fn main() {
  let cache = CacheBuilder::new(cap, max_cost)
        .set_callback(FooCacheCallback::new())
        .finalize()
        .expect("failed to create cache");
}

[0xtyls]

I'm using AsyncCache and get this compiling error:

expected struct DefaultCacheCallback, found struct FooCacheCallback

[0xtyls]

I figured it out. Instead of using type AsyncCache<String, PathBuf>, I need to use AsyncCache<String, PathBuf, DefaultKeyBuilder, DefaultCoster, DefaultUpdateValidator, FooCacheCallback>