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pub use serde::de::DeserializeOwned;
pub use serde::ser::Serialize;
pub mod format;
#[derive(Debug)]
pub struct StringError(pub String);
impl std::fmt::Display for StringError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
self.0.fmt(f)
}
}
impl std::error::Error for StringError {}
#[derive(Debug)]
pub enum RemoveError {
IoError(Box<dyn std::error::Error>),
NoSuchKey,
}
#[derive(Debug)]
pub enum LoadRawError {
IoError(Box<dyn std::error::Error>),
NoSuchKey,
}
#[derive(Debug)]
pub enum LoadError<E> {
Raw(LoadRawError),
FormatError(E),
}
#[derive(Debug)]
pub enum StoreRawError {
IoError(Box<dyn std::error::Error>),
}
#[derive(Debug)]
pub enum StoreError<E> {
Raw(StoreRawError),
FormatError(E),
}
pub trait StorageFormat {
type SerializeError;
type DeserializeError;
fn to_vec<T: ?Sized>(value: &T) -> Result<Vec<u8>, Self::SerializeError>
where
T: Serialize;
fn from_slice<T>(v: &[u8]) -> Result<T, Self::DeserializeError>
where
T: DeserializeOwned;
}
pub trait Storage {
fn exists<K>(&self, key: K) -> bool
where
K: AsRef<str>;
fn clear(&mut self);
fn remove<K>(&mut self, key: K) -> Result<(), RemoveError>
where
K: AsRef<str>;
fn load_raw<K>(&self, key: K) -> Result<Vec<u8>, LoadRawError>
where
K: AsRef<str>;
fn store_raw<K, V>(&mut self, key: K, value: V) -> Result<(), StoreRawError>
where
K: AsRef<str>,
V: AsRef<[u8]>;
fn load<K, T, F>(&self, key: K, format: F) -> Result<T, LoadError<F::DeserializeError>>
where
K: AsRef<str>,
T: DeserializeOwned,
F: StorageFormat,
{
let _ = format;
self.load_raw(key)
.map_err(LoadError::Raw)
.and_then(|v| F::from_slice(&v).map_err(LoadError::FormatError))
}
fn store<K, T, F>(
&mut self,
key: K,
value: &T,
format: F,
) -> Result<(), StoreError<F::SerializeError>>
where
K: AsRef<str>,
T: Serialize,
F: StorageFormat,
{
let _ = format;
F::to_vec(value)
.map_err(StoreError::FormatError)
.and_then(|v| self.store_raw(key, v).map_err(StoreError::Raw))
}
}