rtcache 0.1.1

A read-through/write-back cache
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47

# rtcache

A read-through/write-back caching library.

To create a cache, first define a store and implement the `Store` trait:

```rust
struct TestStore {
    data: Arc<Mutex<HashMap<i32, String>>>,
}

impl TestStore {
    fn new(data: Arc<Mutex<HashMap<i32, String>>>) -> Self {
        Self { data }
    }
}

#[async_trait]
impl Store<i32, Mutex<String>> for TestStore {
    async fn fetch(&self, key: &i32) -> anyhow::Result<Mutex<String>> {
        if let Some(value) = self.data.lock().await.get(key) {
            Ok(Mutex::new(value.clone()))
        } else {
            Err(anyhow::anyhow!("Key not found"))
        }
    }

    // Optional
    async fn update(&self, key: i32, value: Mutex<String>) {
        self.data.lock().await.insert(key, value.into_inner());
    }
}
```

Then, initialize the cache:

```rust
let mut data = HashMap::new();
data.insert(1, String::from("Hello"));
let data = Arc::new(Mutex::new(data));

let mut cache = Cache::new(TestStore::new(data.clone()), Duration::from_secs(60)).await;
```

See examples/examples.rb for more.

The cache internally stores values in `Arc`s and `Cache::get` returns a cloned pointer. If an `Arc<V>` has a reference count more than one, the `Arc` is in use outside of the cache and the key/value pair will not be evicted from the cache.