class Gem::Ext::Builder

def self.class_name
  name =~ /Ext::(.*)Builder/
  $1.downcase
end

def self.make(dest_path, results, make_dir = Dir.pwd)
  unless File.exist? File.join(make_dir, 'Makefile')
    raise Gem::InstallError, 'Makefile not found'
  end
  # try to find make program from Ruby configure arguments first
  RbConfig::CONFIG['configure_args'] =~ /with-make-prog\=(\w+)/
  make_program = ENV['MAKE'] || ENV['make'] || $1
  unless make_program
    make_program = (/mswin/ =~ RUBY_PLATFORM) ? 'nmake' : 'make'
  end
  destdir = '"DESTDIR=%s"' % ENV['DESTDIR']
  ['clean', '', 'install'].each do |target|
    # Pass DESTDIR via command line to override what's in MAKEFLAGS
    cmd = [
      make_program,
      destdir,
      target,
    ].join(' ').rstrip
    begin
      run(cmd, results, "make #{target}".rstrip, make_dir)
    rescue Gem::InstallError
      raise unless target == 'clean' # ignore clean failure
    end
  end
end

def self.run(command, results, command_name = nil, dir = Dir.pwd)
  verbose = Gem.configuration.really_verbose
  begin
    rubygems_gemdeps, ENV['RUBYGEMS_GEMDEPS'] = ENV['RUBYGEMS_GEMDEPS'], nil
    if verbose
      puts("current directory: #{dir}")
      p(command)
    end
    results << "current directory: #{dir}"
    results << (command.respond_to?(:shelljoin) ? command.shelljoin : command)
    require "open3"
    # Set $SOURCE_DATE_EPOCH for the subprocess.
    env = {'SOURCE_DATE_EPOCH' => Gem.source_date_epoch_string}
    output, status = Open3.capture2e(env, *command, :chdir => dir)
    if verbose
      puts output
    else
      results << output
    end
  rescue => error
    raise Gem::InstallError, "#{command_name || class_name} failed#{error.message}"
  ensure
    ENV['RUBYGEMS_GEMDEPS'] = rubygems_gemdeps
  end
  unless status.success?
    results << "Building has failed. See above output for more information on the failure." if verbose
  end
  yield(status, results) if block_given?
  unless status.success?
    exit_reason =
      if status.exited?
        ", exit code #{status.exitstatus}"
      elsif status.signaled?
        ", uncaught signal #{status.termsig}"
      end
    raise Gem::InstallError, "#{command_name || class_name} failed#{exit_reason}"
  end
end

def build_error(output, backtrace = nil) # :nodoc:
  gem_make_out = write_gem_make_out output
  message = <<-EOF
ROR: Failed to build gem native extension.
  #{output}
m files will remain installed in #{@gem_dir} for inspection.
sults logged to #{gem_make_out}
F
  raise Gem::Ext::BuildError, message, backtrace
end

def build_extension(extension, dest_path) # :nodoc:
  results = []
  builder = builder_for(extension)
  extension_dir =
    File.expand_path File.join(@gem_dir, File.dirname(extension))
  lib_dir = File.join @spec.full_gem_path, @spec.raw_require_paths.first
  begin
    FileUtils.mkdir_p dest_path
    results = builder.build(extension, dest_path,
                            results, @build_args, lib_dir, extension_dir)
    verbose { results.join("\n") }
    write_gem_make_out results.join "\n"
  rescue => e
    results << e.message
    build_error(results.join("\n"), $@)
  end
end

def build_extensions
  return if @spec.extensions.empty?
  if @build_args.empty?
    say "Building native extensions. This could take a while..."
  else
    say "Building native extensions with: '#{@build_args.join ' '}'"
    say "This could take a while..."
  end
  dest_path = @spec.extension_dir
  require "fileutils"
  FileUtils.rm_f @spec.gem_build_complete_path
  @spec.extensions.each do |extension|
    break if @ran_rake
    build_extension extension, dest_path
  end
  FileUtils.touch @spec.gem_build_complete_path
end

def builder_for(extension) # :nodoc:
  case extension
  when /extconf/ then
    Gem::Ext::ExtConfBuilder
  when /configure/ then
    Gem::Ext::ConfigureBuilder
  when /rakefile/i, /mkrf_conf/i then
    @ran_rake = true
    Gem::Ext::RakeBuilder
  when /CMakeLists.txt/ then
    Gem::Ext::CmakeBuilder
  else
    build_error("No builder for extension '#{extension}'")
  end
end

def initialize(spec, build_args = spec.build_args)
  @spec       = spec
  @build_args = build_args
  @gem_dir    = spec.full_gem_path
  @ran_rake = false
end

def write_gem_make_out(output) # :nodoc:
  destination = File.join @spec.extension_dir, 'gem_make.out'
  FileUtils.mkdir_p @spec.extension_dir
  File.open destination, 'wb' do |io|
    io.puts output
  end
  destination
end