From 0d4485fd78d5a14797c3511ecf808fcfa0768ac9 Mon Sep 17 00:00:00 2001
From: Alex Blasche <alexander.blasche@theqtcompany.com>
Date: Fri, 9 Jan 2015 11:55:43 +0100
Subject: Support QMetaType::equals()

This avoids having to define operator< for types where operator== is
required but operator< doesn't make any sense (e.g. QGeoCoordinate).

Change-Id: I81f6a9d8fc0009a4514c974b5e02b446c50d1e31
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
---
 src/corelib/kernel/qmetatype.h | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'src/corelib/kernel/qmetatype.h')

diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 5b8c5a6b3d..2ff695b833 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -291,6 +291,24 @@ struct BuiltInComparatorFunction : public AbstractComparatorFunction
     }
 };
 
+template<typename T>
+struct BuiltInEqualsComparatorFunction : public AbstractComparatorFunction
+{
+    BuiltInEqualsComparatorFunction()
+        : AbstractComparatorFunction(0, equals, destroy) {}
+    static bool equals(const AbstractComparatorFunction *, const void *l, const void *r)
+    {
+        const T *lhs = static_cast<const T *>(l);
+        const T *rhs = static_cast<const T *>(r);
+        return *lhs == *rhs;
+    }
+
+    static void destroy(AbstractComparatorFunction *_this)
+    {
+        delete static_cast<BuiltInEqualsComparatorFunction *>(_this);
+    }
+};
+
 struct AbstractConverterFunction
 {
     typedef bool (*Converter)(const AbstractConverterFunction *, const void *, void*);
@@ -529,6 +547,16 @@ public:
         static const QtPrivate::BuiltInComparatorFunction<T> f;
         return registerComparatorFunction( &f, typeId);
     }
+    template<typename T>
+    static bool registerEqualsComparator()
+    {
+        Q_STATIC_ASSERT_X((!QMetaTypeId2<T>::IsBuiltIn),
+            "QMetaType::registerEqualsComparator: The type must be a custom type.");
+        const int typeId = qMetaTypeId<T>();
+        static const QtPrivate::BuiltInEqualsComparatorFunction<T> f;
+        return registerComparatorFunction( &f, typeId);
+    }
+
     template<typename T>
     static bool hasRegisteredComparators()
     {
@@ -610,6 +638,7 @@ public:
 
     static bool convert(const void *from, int fromTypeId, void *to, int toTypeId);
     static bool compare(const void *lhs, const void *rhs, int typeId, int* result);
+    static bool equals(const void *lhs, const void *rhs, int typeId, int* result);
     static bool debugStream(QDebug& dbg, const void *rhs, int typeId);
 
     template<typename From, typename To>
-- 
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