tools: simplify on/off attribute printing

refs #4004

Change-Id: Idb666ff4dbeddc37f1cb10710ba3d75f7fe8bdb5

tests/tools/nfdc/format-helpers.t.cpp

@@ -118,6 +118,14 @@ BOOST_AUTO_TEST_CASE(ItemAttributesMultiLine)
   BOOST_CHECK(os.is_equal(" id=500\nuri=udp4://192.0.2.1:6363\n"));
 }
 
+BOOST_AUTO_TEST_CASE(OnOff)
+{
+  output_test_stream os;
+  os << 'A' << text::OnOff{true} << 'B' << text::OnOff{false} << 'C';
+
+  BOOST_CHECK(os.is_equal("AonBoffC"));
+}
+
 BOOST_AUTO_TEST_SUITE_END() // Text
 
 BOOST_AUTO_TEST_SUITE_END() // TestFormatHelpers

tools/nfdc/face-module.cpp

@@ -509,8 +509,8 @@ FaceModule::formatItemText(std::ostream& os, const FaceStatus& item, bool wantMu
 void
 FaceModule::printFaceParams(std::ostream& os, text::ItemAttributes& ia, const ControlParameters& resp)
 {
-  os << ia("reliability") << (resp.getFlagBit(ndn::nfd::BIT_LP_RELIABILITY_ENABLED) ? "on" : "off")
-     << ia("congestion-marking") << (resp.getFlagBit(ndn::nfd::BIT_CONGESTION_MARKING_ENABLED) ? "on" : "off");
+  os << ia("reliability") << text::OnOff{resp.getFlagBit(ndn::nfd::BIT_LP_RELIABILITY_ENABLED)}
+     << ia("congestion-marking") << text::OnOff{resp.getFlagBit(ndn::nfd::BIT_CONGESTION_MARKING_ENABLED)};
   if (resp.hasBaseCongestionMarkingInterval()) {
     os << ia("congestion-marking-interval")
        << text::formatDuration<time::milliseconds>(resp.getBaseCongestionMarkingInterval());

tools/nfdc/format-helpers.cpp

@@ -177,6 +177,12 @@ operator<<(std::ostream& os, const ItemAttributes::Attribute& attr)
   return os << attr.attribute << '=';
 }
 
+std::ostream&
+operator<<(std::ostream& os, OnOff v)
+{
+  return os << (v.flag ? "on" : "off");
+}
+
 std::string
 formatTimestamp(time::system_clock::TimePoint t)
 {

tools/nfdc/format-helpers.hpp

@@ -165,6 +165,16 @@ private:
 std::ostream&
 operator<<(std::ostream& os, const ItemAttributes::Attribute& attr);
 
+/** \brief print boolean as 'on' or 'off'
+ */
+struct OnOff
+{
+  bool flag;
+};
+
+std::ostream&
+operator<<(std::ostream& os, OnOff v);
+
 namespace detail {
 
 template<typename DurationT>