# compat.rb
# Copyright (C) 2010 Red Hat, Inc.

# Authors:
#   Akira TAGOH  <tagoh@redhat.com>

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.

begin
  Shellwords.escape("foo")
rescue NoMethodError
  module Shellwords
    #
    # Escapes a string so that it can be safely used in a Bourne shell
    # command line.
    #
    # Note that a resulted string should be used unquoted and is not
    # intended for use in double quotes nor in single quotes.
    #
    #   open("| grep #{Shellwords.escape(pattern)} file") { |pipe|
    #     # ...
    #   }
    #
    # +String#shellescape+ is a shorthand for this function.
    #
    #   open("| grep #{pattern.shellescape} file") { |pipe|
    #     # ...
    #   }
    #
    def shellescape(str)
      # An empty argument will be skipped, so return empty quotes.
      return "''" if str.empty?

      str = str.dup

      # Process as a single byte sequence because not all shell
      # implementations are multibyte aware.
      str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n])/n, "\\\\\\1")

      # A LF cannot be escaped with a backslash because a backslash + LF
      # combo is regarded as line continuation and simply ignored.
      str.gsub!(/\n/, "'\n'")

      return str
    end

    module_function :shellescape

    class << self
      alias escape shellescape
    end
  end # module Shellwords

  class String
    #
    # call-seq:
    #   str.shellescape => string
    #
    # Escapes +str+ so that it can be safely used in a Bourne shell
    # command line.  See +Shellwords::shellescape+ for details.
    #
    def shellescape
      Shellwords.escape(self)
    end
  end
end