class Xcodeproj::Project::Object::AbstractBuildPhase

def add_file_reference(file)
  build_file = project.new(PBXBuildFile)
  build_file.file_ref = file
  files << build_file
  build_file
end

def clear_build_files
  files.objects.each do |bf|
    remove_build_file(bf)
  end
end

def files_references
  files.map { |bf| bf.file_ref }.uniq
end

def remove_build_file(build_file)
  build_file.file_ref = nil
  build_file.remove_from_project
end

def remove_file_reference(file)
  build_file = files.find { |bf| bf.file_ref == file }
  if build_file
    build_file.file_ref = nil
    build_file.remove_from_project
  end
end