From 73f135fa5b19c9a278fcdf3167561c9c4250643a Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Wed, 18 Mar 2015 02:10:08 +0000
Subject: [PATCH] refs #356 Streaming ops for QJsonObject: value in pair should
 be a reference, to avoid unnecessary copying and object slicing.

---
 src/blackmisc/json.cpp        | 18 +++++++++---------
 src/blackmisc/json.h          | 20 ++++++++++----------
 src/blackmisc/tuple_private.h |  4 ++--
 src/blackmisc/valueobject.h   |  2 +-
 4 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/src/blackmisc/json.cpp b/src/blackmisc/json.cpp
index 428bdccba..011366448 100644
--- a/src/blackmisc/json.cpp
+++ b/src/blackmisc/json.cpp
@@ -167,55 +167,55 @@ QJsonArray &operator<<(QJsonArray &json, const QDateTime &value)
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, int> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const int &> &value)
 {
     json.insert(value.first, QJsonValue(value.second));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, qint16> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const qint16 &> &value)
 {
     json.insert(value.first, QJsonValue(value.second));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, qulonglong> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const qulonglong &> &value)
 {
     json.insert(value.first, QJsonValue(static_cast<int>(value.second)));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, qlonglong> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const qlonglong &> &value)
 {
     json.insert(value.first, QJsonValue(value.second));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, uint> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const uint &> &value)
 {
     json.insert(value.first, QJsonValue(static_cast<int>(value.second)));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, QString> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const QString &> &value)
 {
     json.insert(value.first, QJsonValue(value.second));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, double> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const double &> &value)
 {
     json.insert(value.first, QJsonValue(value.second));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, bool> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const bool &> &value)
 {
     json.insert(value.first, QJsonValue(value.second));
     return json;
 }
 
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, QDateTime> &value)
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const QDateTime &> &value)
 {
     json.insert(value.first, QJsonValue(value.second.toString()));
     return json;
diff --git a/src/blackmisc/json.h b/src/blackmisc/json.h
index 1562342ec..d9f1fa230 100644
--- a/src/blackmisc/json.h
+++ b/src/blackmisc/json.h
@@ -50,7 +50,7 @@ const QJsonValueRef &operator >>(const QJsonValueRef &json, QDateTime &value);
 //! \ingroup JSON
 template<class ENUM> typename
 std::enable_if<std::is_enum<ENUM>::value, QJsonObject>::type
-&operator<<(QJsonObject &json, std::pair<QString, ENUM> value)
+&operator<<(QJsonObject &json, std::pair<QString, const ENUM &> value)
 {
     json.insert(value.first, QJsonValue(static_cast<int>(value.second)));
     return json;
@@ -93,15 +93,15 @@ QJsonArray &operator<<(QJsonArray &json, const QDateTime &value);
 //! \name Streaming operators for QJsonObject (from value)
 //! \ingroup JSON
 //! @{
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, int> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, qint16> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, qlonglong> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, uint> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, qulonglong> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, QString> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, double> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, bool> &value);
-QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, QDateTime> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const int &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const qint16 &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const qlonglong &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const uint &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const qulonglong &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const QString &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const double &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const bool &> &value);
+QJsonObject &operator<<(QJsonObject &json, const std::pair<QString, const QDateTime &> &value);
 //! @}
 
 namespace BlackMisc
diff --git a/src/blackmisc/tuple_private.h b/src/blackmisc/tuple_private.h
index cf45bb962..4d8cc3be4 100644
--- a/src/blackmisc/tuple_private.h
+++ b/src/blackmisc/tuple_private.h
@@ -289,7 +289,7 @@ namespace BlackMisc
             template <class Tu, size_t... Is>
             static void serializeJson(QJsonObject &json, const QStringList &names, const Tu &tu, index_sequence<Is...>)
             {
-                serializeJsonImpl(json, std::make_pair(names[Is], std::get<Is>(tu))...);
+                serializeJsonImpl(json, std::make_pair(names[Is], get_ref<Is>(tu))...);
             }
 
             template <class Tu, size_t... Is>
@@ -301,7 +301,7 @@ namespace BlackMisc
             template <class Tu, size_t... Is>
             static void serializeJson(QJsonObject &json, const Tu &tu, index_sequence<Is...>)
             {
-                serializeJsonImpl(json, std::make_pair(std::get<Is>(tu).m_jsonName, std::get<Is>(tu).m_obj)...);
+                serializeJsonImpl(json, std::make_pair(std::get<Is>(tu).m_jsonName, get_ref<Is>(tu))...);
                 Q_UNUSED(tu); // avoid compiler warning when all attributes are JSON disabled
             }
 
diff --git a/src/blackmisc/valueobject.h b/src/blackmisc/valueobject.h
index abc2a72ac..0239229b7 100644
--- a/src/blackmisc/valueobject.h
+++ b/src/blackmisc/valueobject.h
@@ -292,7 +292,7 @@ namespace BlackMisc
         }
 
         //! operator << for JSON
-        friend QJsonObject& operator<<(QJsonObject &json, const std::pair<QString, Derived> &value)
+        friend QJsonObject& operator<<(QJsonObject &json, const std::pair<QString, const Derived &> &value)
         {
             json.insert(value.first, QJsonValue(value.second.toJson()));
             return json;