Use arc and rwlock

squid/src/helpers/database.rs

@@ -1,10 +1,11 @@
 use crate::models::database::Entity;
-use anyhow::Result;
+use anyhow::{anyhow, Result};
 use squid_algorithm::hashtable::MapAlgorithm;
 use squid_db::Instance;
+use std::sync::{Arc, RwLock};
 
 /// The algorithms managed by Squid.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub enum Algorithm {
     Map(MapAlgorithm),
 }
@@ -18,11 +19,17 @@ impl From<MapAlgorithm> for Algorithm {
 
 /// Adds a value to the database and the algorithm.
 pub fn set<A: Into<Algorithm>>(
-    instance: &mut Instance<Entity>,
+    instance: Arc<RwLock<Instance<Entity>>>,
     algorithm: A,
     value: Entity,
 ) -> Result<()> {
-    instance.set(value.clone())?;
+    instance
+        .write()
+        .map_err(|error| {
+            log::error!("Failed to mutate instance on `set`: {}", error);
+            anyhow!("cannot mutate instance")
+        })?
+        .set(value.clone())?;
 
     match algorithm.into() {
         Algorithm::Map(mut implementation) => {
@@ -37,11 +44,10 @@ pub fn set<A: Into<Algorithm>>(
 
 /// Rank the most used words.
 pub fn rank<A: Into<Algorithm>>(
-    instance: &mut Instance<Entity>,
     algorithm: A,
     length: usize,
-) -> Result<Vec<String>> {
+) -> Vec<(String, usize)> {
     match algorithm.into() {
-        Algorithm::Map(implementation) => Ok(implementation.rank(length)),
+        Algorithm::Map(implementation) => implementation.rank(length),
     }
 }