class Xcodeproj::Helper::TargetDiff

def initialize(project, target1_name, target2_name)
  @project = project
  unless @target1 = @project.targets.find { |target| target.name == target1_name }
    raise ArgumentError, "Target 1 by name `#{target1_name}' not found in the project."
  end
  unless @target2 = @project.targets.find { |target| target.name == target2_name }
    raise ArgumentError, "Target 1 by name `#{target2_name}' not found in the project."
  end
end

def new_source_build_files
  @target2.source_build_phase.files.reject do |target2_build_file|
    @target1.source_build_phase.files.any? do |target1_build_file|
      target1_build_file.file_ref.path == target2_build_file.file_ref.path
    end
  end.sort_by { |build_file| build_file.file_ref.path }
end