class Gem::Commands::WhichCommand

def arguments # :nodoc:
  "FILE          name of file to find"
end

def defaults_str # :nodoc:
  "--no-gems-first --no-all"
end

def description # :nodoc:
  <<-EOF
e which command is like the shell which command and shows you where
e file you wish to require lives.
u can use the which command to help determine why you are requiring a
rsion you did not expect or to look at the content of a file you are
quiring to see why it does not behave as you expect.
  EOF
end

def execute
  found = true
  options[:args].each do |arg|
    arg = arg.sub(/#{Regexp.union(*Gem.suffixes)}$/, '')
    dirs = $LOAD_PATH
    spec = Gem::Specification.find_by_path arg
    if spec
      if options[:search_gems_first]
        dirs = spec.full_require_paths + $LOAD_PATH
      else
        dirs = $LOAD_PATH + spec.full_require_paths
      end
    end
    paths = find_paths arg, dirs
    if paths.empty?
      alert_error "Can't find Ruby library file or shared library #{arg}"
      found = false
    else
      say paths
    end
  end
  terminate_interaction 1 unless found
end

def find_paths(package_name, dirs)
  result = []
  dirs.each do |dir|
    Gem.suffixes.each do |ext|
      full_path = File.join dir, "#{package_name}#{ext}"
      if File.exist? full_path and not File.directory? full_path
        result << full_path
        return result unless options[:show_all]
      end
    end
  end
  result
end

def initialize
  super 'which', 'Find the location of a library file you can require',
        :search_gems_first => false, :show_all => false
  add_option '-a', '--[no-]all', 'show all matching files' do |show_all, options|
    options[:show_all] = show_all
  end
  add_option '-g', '--[no-]gems-first',
             'search gems before non-gems' do |gems_first, options|
    options[:search_gems_first] = gems_first
  end
end

def usage # :nodoc:
  "#{program_name} FILE [FILE ...]"
end