class Object

def cucumber_arity(block)
  a = block.arity
  Cucumber::RUBY_1_8_7 ? (a == -1 ? 0 : a) : a
end

def cucumber_compatible_arity?(args, block)
  ari = cucumber_arity(block)
  len = args.length
  return true if ari == len or ari < 0 && len >= ari.abs-1
  false
end

def cucumber_instance_exec(check_arity, pseudo_method, *args, &block)
  cucumber_run_with_backtrace_filtering(pseudo_method) do
    if check_arity && !cucumber_compatible_arity?(args, block)
      instance_exec do
        ari = cucumber_arity(block)
        ari = ari < 0 ? (ari.abs-1).to_s+"+" : ari
        s1 = ari == 1 ? "" : "s"
        s2 = args.length == 1 ? "" : "s"
        raise Cucumber::ArityMismatchError.new(
          "Your block takes #{ari} argument#{s1}, but the Regexp matched #{args.length} argument#{s2}."
        )
      end
    else
      instance_exec(*args, &block)
    end
  end
end

def cucumber_run_with_backtrace_filtering(pseudo_method)
  begin
    yield
  rescue Exception => e
    instance_exec_invocation_line = "#{__FILE__}:#{__LINE__ - 2}:in `cucumber_run_with_backtrace_filtering'"
    replace_instance_exec_invocation_line!((e.backtrace || []), instance_exec_invocation_line, pseudo_method)
    raise e
  end
end

def instance_exec(*args, &block)
  begin
    old_critical, Thread.critical = Thread.critical, true
    n = 0
    n += 1 while respond_to?(mname="__instance_exec#{n}")
    InstanceExecHelper.module_eval{ define_method(mname, &block) }
  ensure
    Thread.critical = old_critical
  end
  begin
    ret = send(mname, *args)
  ensure
    InstanceExecHelper.module_eval{ remove_method(mname) } rescue nil
  end
  ret
end

def replace_instance_exec_invocation_line!(backtrace, instance_exec_invocation_line, pseudo_method)
  return if Cucumber.use_full_backtrace
  instance_exec_pos = backtrace.index(instance_exec_invocation_line)
  if instance_exec_pos
    replacement_line = instance_exec_pos + INSTANCE_EXEC_OFFSET
    if Cucumber::RUBY_1_8_7
      backtrace[replacement_line] += ":in `#{pseudo_method}'" if pseudo_method
    else
      backtrace[replacement_line].gsub!(/`.*'/, "`#{pseudo_method}'") if pseudo_method
    end
    depth = backtrace.count { |line| line == instance_exec_invocation_line }
    end_pos = depth > 1 ? instance_exec_pos : -1
    backtrace[replacement_line+1..end_pos] = nil
    backtrace.compact!
  else
    # This happens with rails, because they screw up the backtrace
    # before we get here (injecting erb stacktrace and such)
  end
end