Optimize PackagesCollection.

src/packages/mod.rs

@@ -50,33 +50,44 @@ pub type PackageLibrary = Shared<Module>;
 /// Type containing a collection of `PackageLibrary` instances.
 /// All function and type iterator keys in the loaded packages are indexed for fast access.
 #[derive(Debug, Clone, Default)]
-pub(crate) struct PackagesCollection(StaticVec<PackageLibrary>);
+pub(crate) struct PackagesCollection(Option<StaticVec<PackageLibrary>>);
 
 impl PackagesCollection {
     /// Add a `PackageLibrary` into the `PackagesCollection`.
     ///
     /// Packages are searched in reverse order.
     pub fn add(&mut self, package: PackageLibrary) {
+        if self.0.is_none() {
+            self.0 = Some(Default::default());
+        }
         // Later packages override previous ones.
-        self.0.insert(0, package);
+        self.0.as_mut().unwrap().insert(0, package);
     }
     /// Does the specified function hash key exist in the `PackagesCollection`?
     #[allow(dead_code)]
     pub fn contains_fn(&self, hash: u64) -> bool {
-        self.0.iter().any(|p| p.contains_fn(hash, false))
+        self.0
+            .as_ref()
+            .map_or(false, |x| x.iter().any(|p| p.contains_fn(hash, false)))
     }
     /// Get specified function via its hash key.
     pub fn get_fn(&self, hash: u64) -> Option<&CallableFunction> {
-        self.0.iter().find_map(|p| p.get_fn(hash, false))
+        self.0
+            .as_ref()
+            .and_then(|x| x.iter().find_map(|p| p.get_fn(hash, false)))
     }
     /// Does the specified TypeId iterator exist in the `PackagesCollection`?
     #[allow(dead_code)]
     pub fn contains_iter(&self, id: TypeId) -> bool {
-        self.0.iter().any(|p| p.contains_iter(id))
+        self.0
+            .as_ref()
+            .map_or(false, |x| x.iter().any(|p| p.contains_iter(id)))
     }
     /// Get the specified TypeId iterator.
     pub fn get_iter(&self, id: TypeId) -> Option<IteratorFn> {
-        self.0.iter().find_map(|p| p.get_iter(id))
+        self.0
+            .as_ref()
+            .and_then(|x| x.iter().find_map(|p| p.get_iter(id)))
     }
 }