Reduce the number of submodule calls for diff filesid-submodule-url-graphql

Now 1 request is performed instead of 2 per submodule

3 files changed, 36 insertions, 16 deletions

diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index 87284776db0..a7d9ba51277 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -1071,7 +1071,8 @@ module Gitlab
 
         return unless commit_object && commit_object.type == :COMMIT
 
-        gitaly_submodule_urls_for(ref)[path]
+        urls = gitaly_submodule_urls_for(ref)
+        urls && urls[path]
       end
 
       def gitaly_submodule_urls_for(ref)
diff --git a/lib/gitlab/graphql/representation/submodule_tree_entry.rb b/lib/gitlab/graphql/representation/submodule_tree_entry.rb
index 80d254ce68a..65716dff75d 100644
--- a/lib/gitlab/graphql/representation/submodule_tree_entry.rb
+++ b/lib/gitlab/graphql/representation/submodule_tree_entry.rb
@@ -5,35 +5,28 @@ module Gitlab
     module Representation
       class SubmoduleTreeEntry < SimpleDelegator
         class << self
-          def decorate(tree)
+          def decorate(submodules, tree)
             repository = tree.repository
-            submodule_urls = repository.submodule_urls_for(tree.sha)
+            submodule_links = Gitlab::SubmoduleLinks.new(repository)
 
-            tree.submodules.map do |submodule|
-              self.new(submodule, submodule_urls[submodule.path], repository)
+            submodules.map do |submodule|
+              self.new(submodule, submodule_links.for(submodule, tree.sha))
             end
           end
         end
 
-        def initialize(submodule, submodule_url, repository)
-          @submodule_url = submodule_url
-          @repository = repository
+        def initialize(submodule, submodule_links)
+          @submodule_links = submodule_links
 
           super(submodule)
         end
 
         def web_url
-          submodule_links.first
+          @submodule_links.first
         end
 
         def tree_url
-          submodule_links.last
-        end
-
-        private
-
-        def submodule_links
-          @links ||= SubmoduleHelper.submodule_links_for_url(id, @submodule_url, @repository)
+          @submodule_links.last
         end
       end
     end
diff --git a/lib/gitlab/submodule_links.rb b/lib/gitlab/submodule_links.rb
new file mode 100644
index 00000000000..a6c0369d864
--- /dev/null
+++ b/lib/gitlab/submodule_links.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Gitlab
+  class SubmoduleLinks
+    include Gitlab::Utils::StrongMemoize
+
+    def initialize(repository)
+      @repository = repository
+    end
+
+    def for(submodule, sha)
+      submodule_url = submodule_url_for(sha)[submodule.path]
+      SubmoduleHelper.submodule_links_for_url(submodule.id, submodule_url, repository)
+    end
+
+    private
+
+    attr_reader :repository
+
+    def submodule_url_for(sha)
+      strong_memoize(:"submodule_links_for_#{sha}") do
+        repository.submodule_urls_for(sha)
+      end
+    end
+  end
+end