bazzar/crates/cache-adapter/src/lib.rs

#![feature(box_into_inner)]

use std::borrow::Cow;

use async_trait::async_trait;
pub use config::PluginConfig;
use tracing::warn;

#[derive(Debug, thiserror::Error)]
pub enum Error {
    #[error("Unable to connect")]
    Connect,
    #[error("Entry is invalid")]
    InvalidEntry,
    #[error("Can't invalidate keys {0:?}")]
    Invalidate(Vec<String>),
    #[error("Failed to parse config")]
    InvalidConfig,
}

pub type CResult<T> = Result<T, Error>;

#[derive(Debug)]
pub enum InvalidatePattern<'s> {
    StartsWith(Cow<'s, str>),
    EndsWith(Cow<'s, str>),
    Contains(Cow<'s, str>),
    Const(Cow<'s, str>),
}

pub struct CacheObject(pub Option<Vec<u8>>);

impl CacheObject {
    pub fn into_inner<T>(self) -> CResult<Option<T>>
    where
        T: serde::de::DeserializeOwned,
    {
        let Some(data) = self.0 else {
            return Ok(None)
        };
        bincode::deserialize(&data)
            .map_err(|e| {
                warn!("Malformed cache entry: {e}");
                Error::InvalidEntry
            })
            .map(Some)
    }
}

#[async_trait]
pub trait CacheAdapter {
    async fn new(config: PluginConfig) -> CResult<Self>
    where
        Self: Sized;

    async fn read(&self, key: &str) -> CResult<CacheObject>;

    async fn set(
        &mut self,
        key: &str,
        data: &[u8],
        expires_in: Option<std::time::Duration>,
    ) -> CResult<()>;

    async fn invalidate(&mut self, pattern: InvalidatePattern<'_>) -> CResult<u64>;

    async fn clear(&mut self) -> CResult<u64>;
}