From 07e64099b1573a15768994555720bcf11112ae69 Mon Sep 17 00:00:00 2001
From: Mat Sutcliffe <oktal3700@gmail.com>
Date: Wed, 25 Sep 2019 21:11:19 +0100
Subject: [PATCH] Ref T725 Extend CLogMessage to allow ICoordinateGeodetic
 arguments, using a system of traits to select the stringifier corresponding
 to the argument type.

---
 src/blackmisc/geo/coordinategeodetic.h | 12 +++-
 src/blackmisc/statusmessage.h          | 21 ++----
 src/blackmisc/stringutils.h            | 97 ++++++++++++++++++++++++++
 src/blackmisc/typetraits.h             | 19 +++++
 4 files changed, 130 insertions(+), 19 deletions(-)

diff --git a/src/blackmisc/geo/coordinategeodetic.h b/src/blackmisc/geo/coordinategeodetic.h
index 307066dc9..e312355b4 100644
--- a/src/blackmisc/geo/coordinategeodetic.h
+++ b/src/blackmisc/geo/coordinategeodetic.h
@@ -20,6 +20,7 @@
 #include "blackmisc/math/mathutils.h"
 #include "blackmisc/metaclass.h"
 #include "blackmisc/propertyindex.h"
+#include "blackmisc/stringutils.h"
 #include "blackmisc/valueobject.h"
 #include "blackmisc/variant.h"
 #include "blackmisc/blackmiscexport.h"
@@ -135,9 +136,6 @@ namespace BlackMisc
             //! \copydoc Mixin::String::toQString
             QString convertToQString(bool i18n = false) const;
 
-            //! \copydoc Mixin::String::toQString
-            // QString toQString(bool i18n = false) const { return this->convertToQString(i18n); }
-
             //! Check values @{
             bool isNaNVector() const;
             bool isNaNVectorDouble() const;
@@ -353,6 +351,14 @@ namespace BlackMisc
             );
         };
     } // namespace
+
+    //! \cond
+    template <>
+    struct TString<Geo::ICoordinateGeodetic>
+    {
+        static QString toQString(const Geo::ICoordinateGeodetic &coord) { return coord.convertToQString(); }
+    };
+    //! \endcond
 } // namespace
 
 Q_DECLARE_METATYPE(BlackMisc::Geo::CCoordinateGeodetic)
diff --git a/src/blackmisc/statusmessage.h b/src/blackmisc/statusmessage.h
index d430ef357..f5df51ae6 100644
--- a/src/blackmisc/statusmessage.h
+++ b/src/blackmisc/statusmessage.h
@@ -16,6 +16,7 @@
 #include "orderable.h"
 #include "icon.h"
 #include "propertyindex.h"
+#include "stringutils.h"
 #include "typetraits.h"
 #include "blackmiscexport.h"
 
@@ -234,22 +235,10 @@ namespace BlackMisc
         //!          Otherwise, the streamed values will replace the place markers %1, %2, %3... in the format string.
         //! \see QString::arg
         //! @{
-        Derived &operator <<(const QString &v) { return arg(v); }
-        Derived &operator <<(const QStringRef &v) { return arg(v.toString()); }
-        Derived &operator <<(QStringView v) { return arg(v.toString()); }
-        Derived &operator <<(int v) { return arg(QString::number(v)); }
-        Derived &operator <<(uint v) { return arg(QString::number(v)); }
-        Derived &operator <<(long v) { return arg(QString::number(v)); }
-        Derived &operator <<(ulong v) { return arg(QString::number(v)); }
-        Derived &operator <<(qlonglong v) { return arg(QString::number(v)); }
-        Derived &operator <<(qulonglong v) { return arg(QString::number(v)); }
-        Derived &operator <<(short v) { return arg(QString::number(v)); }
-        Derived &operator <<(ushort v) { return arg(QString::number(v)); }
-        Derived &operator <<(QChar v) { return arg(v); }
-        Derived &operator <<(char v) { return arg(QChar(v)); }
-        Derived &operator <<(double v) { return arg(QString::number(v)); }
-        template <class T, class = std::enable_if_t<THasToQString<T>::value>>
-        Derived & operator <<(const T &v) { return arg(v.toQString()); }
+        template <class T, std::enable_if_t<TParameter<std::decay_t<T>>::passBy == ParameterPassBy::Value, int> = 0>
+        Derived &operator <<(T v) { return arg(TString<T>::toQString(v)); }
+        template <class T, std::enable_if_t<TParameter<std::decay_t<T>>::passBy == ParameterPassBy::ConstRef, int> = 0>
+        Derived &operator <<(const T &v) { return arg(TString<T>::toQString(v)); }
         //! @}
 
         //! Message empty
diff --git a/src/blackmisc/stringutils.h b/src/blackmisc/stringutils.h
index dbdbec302..c82847662 100644
--- a/src/blackmisc/stringutils.h
+++ b/src/blackmisc/stringutils.h
@@ -13,19 +13,23 @@
 
 #include "blackmisc/blackmiscexport.h"
 #include "blackmisc/range.h"
+#include "blackmisc/typetraits.h"
 
 #include <QByteArray>
 #include <QDataStream>
 #include <QDateTime>
 #include <QDebug>
+#include <QFlags>
 #include <QList>
 #include <QMapIterator>
 #include <QString>
 #include <QStringRef>
+#include <QStringView>
 #include <QTextStream>
 #include <QtGlobal>
 #include <QSet>
 #include <QMap>
+#include <atomic>
 #include <iosfwd>
 #include <string>
 #include <algorithm>
@@ -372,6 +376,99 @@ namespace BlackMisc
             using ::BlackMisc::Mixin::String<DERIVED>::stringForStreaming;
         // *INDENT-ON*
     } // ns
+
+    /*!
+     * Stringification traits class.
+     */
+    template <typename T, typename = void> struct TString;
+
+    // Stringification traits specializations.
+    //! \cond
+    template <> struct TString<QString>
+    {
+        static QString toQString(const QString &s) { return s; }
+    };
+    template <> struct TString<QStringRef>
+    {
+        static QString toQString(const QStringRef &sr) { return sr.toString(); }
+    };
+    template <> struct TString<QStringView>
+    {
+        static QString toQString(QStringView sv) { return sv.toString(); }
+    };
+    template <> struct TString<QChar>
+    {
+        static QString toQString(QChar c) { return c; }
+    };
+    template <> struct TString<char>
+    {
+        static QString toQString(char c) { return QChar(c); }
+    };
+    template <> struct TString<bool>
+    {
+        static QString toQString(bool n) { return QString::number(n); }
+    };
+    template <> struct TString<int>
+    {
+        static QString toQString(int n) { return QString::number(n); }
+    };
+    template <> struct TString<uint>
+    {
+        static QString toQString(uint n) { return QString::number(n); }
+    };
+    template <> struct TString<long>
+    {
+        static QString toQString(long n) { return QString::number(n); }
+    };
+    template <> struct TString<ulong>
+    {
+        static QString toQString(ulong n) { return QString::number(n); }
+    };
+    template <> struct TString<qlonglong>
+    {
+        static QString toQString(qlonglong n) { return QString::number(n); }
+    };
+    template <> struct TString<qulonglong>
+    {
+        static QString toQString(qulonglong n) { return QString::number(n); }
+    };
+    template <> struct TString<short>
+    {
+        static QString toQString(short n) { return QString::number(n); }
+    };
+    template <> struct TString<ushort>
+    {
+        static QString toQString(ushort n) { return QString::number(n); }
+    };
+    template <> struct TString<float>
+    {
+        static QString toQString(float n) { return QString::number(n); }
+    };
+    template <> struct TString<double>
+    {
+        static QString toQString(double n) { return QString::number(n); }
+    };
+    template <typename T> struct TString<T, std::enable_if_t<std::is_enum<T>::value>>
+    {
+        static QString toQString(T e) { return QString::number(e); }
+    };
+    template <typename T> struct TString<T, std::enable_if_t<std::is_convertible<T, QString>::value>>
+    {
+        static QString toQString(const T &v) { return v; }
+    };
+    template <typename T> struct TString<T, std::enable_if_t<THasToQString<T>::value>>
+    {
+        static QString toQString(const T &v) { return v.toQString(); }
+    };
+    template <typename T> struct TString<QFlags<T>>
+    {
+        static QString toQString(QFlags<T> n) { return TString<typename QFlags<T>::Int>::toQString(n); }
+    };
+    template <typename T> struct TString<std::atomic<T>>
+    {
+        static QString toQString(const std::atomic<T> &n) { return TString<T>::toQString(n); }
+    };
+    //! \endcond
 } // ns
 
 #endif // guard
diff --git a/src/blackmisc/typetraits.h b/src/blackmisc/typetraits.h
index e2e124489..1ef431926 100644
--- a/src/blackmisc/typetraits.h
+++ b/src/blackmisc/typetraits.h
@@ -52,6 +52,25 @@ namespace BlackMisc
         //! \endcond
     }
 
+    /*!
+     * Whether an input parameter type should be passed by value or by const reference.
+     */
+    enum class ParameterPassBy
+    {
+        Value,
+        ConstRef
+    };
+
+    /*!
+     * Trait to detect properties of function parameter types.
+     */
+    template <typename T>
+    struct TParameter
+    {
+        //! Whether the input parameter type T should be passed by value or by const reference.
+        static constexpr ParameterPassBy passBy = (sizeof(T) <= 16 && std::is_trivially_copy_constructible<T>::value && std::is_trivially_destructible<T>::value) ? ParameterPassBy::Value : ParameterPassBy::ConstRef;
+    };
+
     /*!
      * Trait to detect whether T contains a member function toQString.
      */