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use std::io::{Read, Write};
use std::path::{Path, PathBuf};
use std::sync::{Arc, RwLock};
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use crate::error::Error;
use crate::migrate::Migrate;
pub struct Persister<T: Migrate> {
path: PathBuf,
_marker: std::marker::PhantomData<T>,
}
impl<T: Migrate> Persister<T> {
pub fn new(base_dir: &Path, file_name: &str) -> Self {
let mut path = base_dir.to_path_buf();
path.push(file_name);
Self {
path,
_marker: Default::default(),
}
}
fn decode(&self, bytes: &[u8]) -> Result<T, Error> {
match T::decode(bytes) {
Some(v) => Ok(v),
None => {
error!(
"Unable to decode persisted data file {}",
self.path.display()
);
for line in hexdump::hexdump_iter(bytes) {
debug!("{}", line);
}
Err(Error::Message(format!(
"Unable to decode persisted data file {}",
self.path.display()
)))
}
}
}
pub fn load(&self) -> Result<T, Error> {
let mut file = std::fs::OpenOptions::new().read(true).open(&self.path)?;
let mut bytes = vec![];
file.read_to_end(&mut bytes)?;
let value = self.decode(&bytes[..])?;
Ok(value)
}
pub fn save(&self, t: &T) -> Result<(), Error> {
let bytes = t.encode()?;
let mut file = std::fs::OpenOptions::new()
.write(true)
.create(true)
.truncate(true)
.open(&self.path)?;
file.write_all(&bytes[..])?;
Ok(())
}
pub async fn load_async(&self) -> Result<T, Error> {
let mut file = tokio::fs::File::open(&self.path).await?;
let mut bytes = vec![];
file.read_to_end(&mut bytes).await?;
let value = self.decode(&bytes[..])?;
Ok(value)
}
pub async fn save_async(&self, t: &T) -> Result<(), Error> {
let bytes = t.encode()?;
let mut file = tokio::fs::File::create(&self.path).await?;
file.write_all(&bytes[..]).await?;
Ok(())
}
}
pub struct PersisterShared<V: Migrate + Default>(Arc<(Persister<V>, RwLock<V>)>);
impl<V: Migrate + Default> Clone for PersisterShared<V> {
fn clone(&self) -> PersisterShared<V> {
PersisterShared(self.0.clone())
}
}
impl<V: Migrate + Default> PersisterShared<V> {
pub fn new(base_dir: &Path, file_name: &str) -> Self {
let persister = Persister::new(base_dir, file_name);
let value = persister.load().unwrap_or_default();
Self(Arc::new((persister, RwLock::new(value))))
}
pub fn get_with<F, R>(&self, f: F) -> R
where
F: FnOnce(&V) -> R,
{
let value = self.0 .1.read().unwrap();
f(&value)
}
pub fn set_with<F>(&self, f: F) -> Result<(), Error>
where
F: FnOnce(&mut V),
{
let mut value = self.0 .1.write().unwrap();
f(&mut value);
self.0 .0.save(&value)
}
}
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