1 files changed, 115 insertions, 0 deletions
diff --git a/app/models/packages/go/module_version.rb b/app/models/packages/go/module_version.rb
new file mode 100644
index 00000000000..a50c78f8e69
--- /dev/null
+++ b/app/models/packages/go/module_version.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+module Packages
+  module Go
+    class ModuleVersion
+      include Gitlab::Utils::StrongMemoize
+
+      VALID_TYPES = %i[ref commit pseudo].freeze
+
+      attr_reader :mod, :type, :ref, :commit
+
+      delegate :major, to: :@semver, allow_nil: true
+      delegate :minor, to: :@semver, allow_nil: true
+      delegate :patch, to: :@semver, allow_nil: true
+      delegate :prerelease, to: :@semver, allow_nil: true
+      delegate :build, to: :@semver, allow_nil: true
+
+      def initialize(mod, type, commit, name: nil, semver: nil, ref: nil)
+        raise ArgumentError.new("invalid type '#{type}'") unless VALID_TYPES.include? type
+        raise ArgumentError.new("mod is required") unless mod
+        raise ArgumentError.new("commit is required") unless commit
+
+        if type == :ref
+          raise ArgumentError.new("ref is required") unless ref
+        elsif type == :pseudo
+          raise ArgumentError.new("name is required") unless name
+          raise ArgumentError.new("semver is required") unless semver
+        end
+
+        @mod = mod
+        @type = type
+        @commit = commit
+        @name = name if name
+        @semver = semver if semver
+        @ref = ref if ref
+      end
+
+      def name
+        @name || @ref&.name
+      end
+
+      def full_name
+        "#{mod.name}@#{name || commit.sha}"
+      end
+
+      def gomod
+        strong_memoize(:gomod) do
+          if strong_memoized?(:blobs)
+            blob_at(@mod.path + '/go.mod')
+          elsif @mod.path.empty?
+            @mod.project.repository.blob_at(@commit.sha, 'go.mod')&.data
+          else
+            @mod.project.repository.blob_at(@commit.sha, @mod.path + '/go.mod')&.data
+          end
+        end
+      end
+
+      def archive
+        suffix_len = @mod.path == '' ? 0 : @mod.path.length + 1
+
+        Zip::OutputStream.write_buffer do |zip|
+          files.each do |file|
+            zip.put_next_entry "#{full_name}/#{file[suffix_len...]}"
+            zip.write blob_at(file)
+          end
+        end
+      end
+
+      def files
+        strong_memoize(:files) do
+          ls_tree.filter { |e| !excluded.any? { |n| e.start_with? n } }
+        end
+      end
+
+      def excluded
+        strong_memoize(:excluded) do
+          ls_tree
+            .filter { |f| f.end_with?('/go.mod') && f != @mod.path + '/go.mod' }
+            .map    { |f| f[0..-7] }
+        end
+      end
+
+      def valid?
+        @mod.path_valid?(major) && @mod.gomod_valid?(gomod)
+      end
+
+      private
+
+      def blob_at(path)
+        return if path.nil? || path.empty?
+
+        path = path[1..] if path.start_with? '/'
+
+        blobs.find { |x| x.path == path }&.data
+      end
+
+      def blobs
+        strong_memoize(:blobs) { @mod.project.repository.batch_blobs(files.map { |x| [@commit.sha, x] }) }
+      end
+
+      def ls_tree
+        strong_memoize(:ls_tree) do
+          path =
+            if @mod.path.empty?
+              '.'
+            else
+              @mod.path
+            end
+
+          @mod.project.repository.gitaly_repository_client.search_files_by_name(@commit.sha, path)
+        end
+      end
+    end
+  end
+end