module Gem::Util

def self.gunzip(data)
  require 'zlib'
  require 'stringio'
  data = StringIO.new(data, 'r')
  unzipped = Zlib::GzipReader.new(data).read
  unzipped.force_encoding Encoding::BINARY if Object.const_defined? :Encoding
  unzipped
end

def self.gzip(data)
  require 'zlib'
  require 'stringio'
  zipped = StringIO.new(String.new, 'w')
  zipped.set_encoding Encoding::BINARY if Object.const_defined? :Encoding
  Zlib::GzipWriter.wrap zipped do |io| io.write data end
  zipped.string
end

def self.inflate(data)
  require 'zlib'
  Zlib::Inflate.inflate data
end

def self.popen *command
  IO.popen command, &:read
rescue TypeError # ruby 1.8 only supports string command
  r, w = IO.pipe
  pid = fork do
    STDIN.close
    STDOUT.reopen w
    exec(*command)
  end
  w.close
  begin
    return r.read
  ensure
    Process.wait pid
  end
end

def self.silent_system *command
  opt = {:out => NULL_DEVICE, :err => [:child, :out]}
  if Hash === command.last
    opt.update(command.last)
    cmds = command[0...-1]
  else
    cmds = command.dup
  end
  return system(*(cmds << opt))
rescue TypeError
  require 'thread'
  @silent_mutex ||= Mutex.new
  null_device = NULL_DEVICE
  @silent_mutex.synchronize do
    begin
      stdout = STDOUT.dup
      stderr = STDERR.dup
      STDOUT.reopen null_device, 'w'
      STDERR.reopen null_device, 'w'
      return system(*command)
    ensure
      STDOUT.reopen stdout
      STDERR.reopen stderr
      stdout.close
      stderr.close
    end
  end
end

def self.traverse_parents directory
  return enum_for __method__, directory unless block_given?
  here = File.expand_path directory
  start = here
  Dir.chdir start
  begin
    loop do
      yield here
      Dir.chdir '..'
      return if Dir.pwd == here # toplevel
      here = Dir.pwd
    end
  ensure
    Dir.chdir start
  end
end