Introduce HashedPath class

This class centralizes the business logic of
disk path for a given uploader.

app/uploaders/job_artifact_uploader.rb

@@ -36,15 +36,10 @@ class JobArtifactUploader < GitlabUploader
   end
 
   def hashed_path
-    File.join(disk_hash[0..1], disk_hash[2..3], disk_hash,
-      model.created_at.utc.strftime('%Y_%m_%d'), model.job_id.to_s, model.id.to_s)
+    Gitlab::HashedPath.new(model.created_at.utc.strftime('%Y_%m_%d'), model.job_id, model.id, root_hash: model.project_id)
   end
 
   def legacy_path
     File.join(model.created_at.utc.strftime('%Y_%m'), model.project_id.to_s, model.job_id.to_s)
   end
-
-  def disk_hash
-    @disk_hash ||= Digest::SHA2.hexdigest(model.project_id.to_s)
-  end
 end

app/uploaders/packages/package_file_uploader.rb

@@ -20,11 +20,6 @@ class Packages::PackageFileUploader < GitlabUploader
   private
 
   def dynamic_segment
-    File.join(disk_hash[0..1], disk_hash[2..3], disk_hash,
-              'packages', model.package.id.to_s, 'files', model.id.to_s)
-  end
-
-  def disk_hash
-    @disk_hash ||= Digest::SHA2.hexdigest(model.package.project_id.to_s)
+    Gitlab::HashedPath.new('packages', model.package.id, 'files', model.id, root_hash: model.package.project_id)
   end
 end

ee/app/uploaders/dependency_proxy/file_uploader.rb

@@ -18,11 +18,6 @@ class DependencyProxy::FileUploader < GitlabUploader
   private
 
   def dynamic_segment
-    File.join(disk_hash[0..1], disk_hash[2..3], disk_hash,
-              'dependency_proxy', model.group_id.to_s, 'files', model.id.to_s)
-  end
-
-  def disk_hash
-    @disk_hash ||= Digest::SHA2.hexdigest(model.group_id.to_s)
+    Gitlab::HashedPath.new('dependency_proxy', model.group_id, 'files', model.id, root_hash: model.group_id)
   end
 end

lib/gitlab/hashed_path.rb

+# frozen_string_literal: true
+
+# Class that returns the disk path for a model using hashed storage
+
+module Gitlab
+  class HashedPath
+    def initialize(*paths, root_hash:)
+      @paths = paths
+      @root_hash = root_hash
+    end
+
+    def to_s
+      File.join(disk_hash[0..1], disk_hash[2..3], disk_hash, @paths.map(&:to_s))
+    end
+
+    alias_method :to_str, :to_s
+
+    private
+
+    def disk_hash
+      @disk_hash ||= Digest::SHA2.hexdigest(@root_hash.to_s)
+    end
+  end
+end

spec/lib/gitlab/hashed_path_spec.rb

+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+RSpec.describe Gitlab::HashedPath do
+  let(:root_hash) { 1 }
+  let(:hashed_path) { described_class.new(*path, root_hash: root_hash) }
+
+  describe '#to_s' do
+    subject { hashed_path }
+
+    context 'when path contains a single value' do
+      let(:path) { 'path' }
+
+      it 'returns the disk path' do
+        expect(subject).to match(%r[\h{2}/\h{2}/\h{64}/path])
+      end
+    end
+
+    context 'when path contains multiple values' do
+      let(:path) { %w(path1 path2) }
+
+      it 'returns the disk path' do
+        expect(subject).to match(%r[\h{2}/\h{2}/\h{64}/path1/path2])
+      end
+    end
+  end
+end