garage/src/util/background/vars.rs

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Rust
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use std::collections::HashMap;
use std::str::FromStr;
use crate::error::{Error, OkOrMessage};
use crate::migrate::Migrate;
use crate::persister::PersisterShared;
pub struct BgVars {
vars: HashMap<&'static str, Box<dyn BgVarTrait>>,
}
impl BgVars {
pub fn new() -> Self {
Self {
vars: HashMap::new(),
}
}
pub fn register_rw<V, T, GF, SF>(
&mut self,
p: &PersisterShared<V>,
name: &'static str,
get_fn: GF,
set_fn: SF,
) where
V: Migrate + Default + Send + Sync,
T: FromStr + ToString + Send + Sync + 'static,
GF: Fn(&PersisterShared<V>) -> T + Send + Sync + 'static,
SF: Fn(&PersisterShared<V>, T) -> Result<(), Error> + Send + Sync + 'static,
{
let p1 = p.clone();
let get_fn = move || get_fn(&p1);
let p2 = p.clone();
let set_fn = move |v| set_fn(&p2, v);
self.vars.insert(name, Box::new(BgVar { get_fn, set_fn }));
}
pub fn register_ro<V, T, GF>(&mut self, p: &PersisterShared<V>, name: &'static str, get_fn: GF)
where
V: Migrate + Default + Send + Sync,
T: FromStr + ToString + Send + Sync + 'static,
GF: Fn(&PersisterShared<V>) -> T + Send + Sync + 'static,
{
let p1 = p.clone();
let get_fn = move || get_fn(&p1);
let set_fn = move |_| Err(Error::Message(format!("Cannot set value of {}", name)));
self.vars.insert(name, Box::new(BgVar { get_fn, set_fn }));
}
pub fn get(&self, var: &str) -> Result<String, Error> {
Ok(self
.vars
.get(var)
.ok_or_message("variable does not exist")?
.get())
}
pub fn get_all(&self) -> Vec<(&'static str, String)> {
self.vars.iter().map(|(k, v)| (*k, v.get())).collect()
}
pub fn set(&self, var: &str, val: &str) -> Result<(), Error> {
self.vars
.get(var)
.ok_or_message("variable does not exist")?
.set(val)
}
}
2023-01-04 12:25:57 +00:00
impl Default for BgVars {
fn default() -> Self {
Self::new()
}
}
// ----
trait BgVarTrait: Send + Sync + 'static {
fn get(&self) -> String;
fn set(&self, v: &str) -> Result<(), Error>;
}
struct BgVar<T, GF, SF>
where
T: FromStr + ToString + Send + Sync + 'static,
GF: Fn() -> T + Send + Sync + 'static,
SF: Fn(T) -> Result<(), Error> + Sync + Send + 'static,
{
get_fn: GF,
set_fn: SF,
}
impl<T, GF, SF> BgVarTrait for BgVar<T, GF, SF>
where
T: FromStr + ToString + Sync + Send + 'static,
GF: Fn() -> T + Sync + Send + 'static,
SF: Fn(T) -> Result<(), Error> + Sync + Send + 'static,
{
fn get(&self) -> String {
(self.get_fn)().to_string()
}
fn set(&self, vstr: &str) -> Result<(), Error> {
let value = vstr
.parse()
.map_err(|_| Error::Message(format!("invalid value: {}", vstr)))?;
(self.set_fn)(value)
}
}