# Most functions in this file are based on those in Chris Wanstrath's
# excellent fakefs library (lib/fakefs/base.rb).
#
# The following is a verbatim copy of the original license:
#
#   Copyright (c) 2009 Chris Wanstrath
#
#   Permission is hereby granted, free of charge, to any person obtaining
#   a copy of this software and associated documentation files (the
#   "Software"), to deal in the Software without restriction, including
#   without limitation the rights to use, copy, modify, merge, publish,
#   distribute, sublicense, and/or sell copies of the Software, and to
#   permit persons to whom the Software is furnished to do so, subject to
#   the following conditions:
#
#   The above copyright notice and this permission notice shall be
#   included in all copies or substantial portions of the Software.
#
#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
#   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
#   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
#   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
#   LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
#   OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
#   WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

RealEtc = Etc

module FakeEtc
  @groups = {}

  def self.activated?
    @activated
  end

  def self.activate
    @activated = true
    Object.class_eval do
      remove_const :Etc
      const_set :Etc, FakeEtc
    end
  end

  def self.deactivate
    Object.class_eval do
      remove_const :Etc
      const_set :Etc, RealEtc
    end
    @activated = false
  end

  def self.with
    if activated?
      yield
    else
      begin
        activate
        yield
      ensure
        deactivate
      end
    end
  end

  def self.without
    if !activated?
      yield
    else
      begin
        deactivate
        yield
      ensure
        activate
      end
    end
  end
end

def FakeEtc(&block)
  return ::FakeEtc unless block
  ::FakeEtc.with(&block)
end