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authorAlex Auvolat <alex@adnab.me>2023-01-04 13:07:13 +0100
committerAlex Auvolat <alex@adnab.me>2023-01-04 13:07:13 +0100
commitf3f27293df83986ba29fb03f8af26a2177518e20 (patch)
treeaebfa6b6936a974d40846a4c56b17aefac4f2526 /src/util/background/vars.rs
parent13c554988623663a9416439baf4f85f6fa91e502 (diff)
downloadgarage-f3f27293df83986ba29fb03f8af26a2177518e20.tar.gz
garage-f3f27293df83986ba29fb03f8af26a2177518e20.zip
Uniform framework for bg variable management
Diffstat (limited to 'src/util/background/vars.rs')
-rw-r--r--src/util/background/vars.rs107
1 files changed, 107 insertions, 0 deletions
diff --git a/src/util/background/vars.rs b/src/util/background/vars.rs
new file mode 100644
index 00000000..fe54268e
--- /dev/null
+++ b/src/util/background/vars.rs
@@ -0,0 +1,107 @@
+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)
+ }
+}
+
+// ----
+
+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)
+ }
+}