cache rhai function parsing

Cargo.toml

@@ -89,6 +89,7 @@ merge = "0.1"
 once_cell = "1.19"
 self_update = { version = "0.39", default-features = false, optional = true, features = ["rustls", "archive-tar", "compression-flate2"] }
 toml = "0.8"
+cached = "0.49.3"
 
 [dev-dependencies]
 abscissa_core = { version = "0.7.0", default-features = false, features = ["testing"] }

src/filtering.rs

@@ -4,6 +4,7 @@ use log::warn;
 use rustic_core::{repofile::SnapshotFile, StringList};
 use std::{error::Error, str::FromStr};
 
+use cached::proc_macro::cached;
 use rhai::{serde::to_dynamic, Dynamic, Engine, FnPtr, AST};
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, DisplayFromStr};
@@ -24,6 +25,17 @@ impl FromStr for SnapshotFn {
     }
 }
 
+#[cached(key = "String", convert = r#"{ s.to_string() }"#, size = 1)]
+fn string_to_fn(s: &str) -> Option<SnapshotFn> {
+    match SnapshotFn::from_str(s) {
+        Ok(filter_fn) => Some(filter_fn),
+        Err(err) => {
+            warn!("Error evaluating filter-fn {s}: {err}",);
+            None
+        }
+    }
+}
+
 impl SnapshotFn {
     /// Call the function with a [`SnapshotFile`]
     ///
@@ -87,20 +99,19 @@ impl SnapshotFilter {
     #[must_use]
     pub fn matches(&self, snapshot: &SnapshotFile) -> bool {
         if let Some(filter_fn) = &self.filter_fn {
-            match SnapshotFn::from_str(filter_fn)
-                .unwrap()
-                .call::<bool>(snapshot)
-            {
-                Ok(result) => {
-                    if !result {
-                        return false;
+            if let Some(func) = string_to_fn(filter_fn) {
+                match func.call::<bool>(snapshot) {
+                    Ok(result) => {
+                        if !result {
+                            return false;
+                        }
+                    }
+                    Err(err) => {
+                        warn!(
+                            "Error evaluating filter-fn for snapshot {}: {err}",
+                            snapshot.id
+                        );
                     }
-                }
-                Err(err) => {
-                    warn!(
-                        "Error evaluating filter-fn for snapshot {}: {err}",
-                        snapshot.id
-                    );
                 }
             }
         }