1 files changed, 35 insertions, 0 deletions
diff --git a/crates/shirabe/src/repository/canonical_packages_trait.rs b/crates/shirabe/src/repository/canonical_packages_trait.rs
index cefe02e..3fac07e 100644
--- a/crates/shirabe/src/repository/canonical_packages_trait.rs
+++ b/crates/shirabe/src/repository/canonical_packages_trait.rs
@@ -1 +1,36 @@
 //! ref: composer/src/Composer/Repository/CanonicalPackagesTrait.php
+
+use indexmap::IndexMap;
+use crate::package::package_interface::PackageInterface;
+
+/// Provides get_canonical_packages() to various repository implementations.
+pub trait CanonicalPackagesTrait {
+    fn get_packages(&self) -> Vec<Box<dyn PackageInterface>>;
+
+    /// Get unique packages (at most one package of each name), with aliases resolved and removed.
+    fn get_canonical_packages(&self) -> Vec<Box<dyn PackageInterface>> {
+        let packages = self.get_packages();
+
+        // get at most one package of each name, preferring non-aliased ones
+        let mut packages_by_name: IndexMap<String, Box<dyn PackageInterface>> = IndexMap::new();
+        for package in packages {
+            let name = package.get_name();
+            if !packages_by_name.contains_key(&name) || packages_by_name[&name].is_alias_package() {
+                packages_by_name.insert(name, package);
+            }
+        }
+
+        let mut canonical_packages = Vec::new();
+
+        // unfold aliased packages
+        for mut package in packages_by_name.into_values() {
+            while package.is_alias_package() {
+                package = package.get_alias_of();
+            }
+
+            canonical_packages.push(package);
+        }
+
+        canonical_packages
+    }
+}