From 14de1eda09a5994a3df186693298f6625a6e917a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Szikszai=20Guszt=C3=A1v?= <guszti5@hotmail.com>
Date: Fri, 15 Sep 2017 10:50:11 +0200
Subject: [PATCH] Cache Elm versions of package versions.

Fixes #42
---
 lib/elm_install/git_source.rb | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/lib/elm_install/git_source.rb b/lib/elm_install/git_source.rb
index b78efe7..13ed7e1 100644
--- a/lib/elm_install/git_source.rb
+++ b/lib/elm_install/git_source.rb
@@ -68,6 +68,18 @@ def copy_to(version, directory)
       nil
     end
 
+    Contract String => String
+    # Returns the supported Elm version the given ref.
+    #
+    # @param ref [String] The ref
+    #
+    # @return [Array] The version
+    def elm_version_of(ref)
+      @@elm_versions ||= {}
+      @@elm_versions[url] ||= {}
+      @@elm_versions[url][ref] ||= identifier.elm_version(fetch(ref))
+    end
+
     Contract ArrayOf[Solve::Constraint], String => ArrayOf[Semverse::Version]
     # Returns the available versions for a repository
     #
@@ -101,7 +113,7 @@ def matching_versions(constraints, elm_version)
       repository
         .versions
         .select do |version|
-          identifier.elm_version(fetch(version.to_s)) == elm_version &&
+          elm_version_of(version.to_s) == elm_version &&
             constraints.all? { |constraint| constraint.satisfies?(version) }
         end
         .sort