Add qHash(QVector)

QVectors can be compared for equality, so qHash should be overloaded, too.

[ChangeLog][QtCore][QVector] Added qHash(QVector).

Change-Id: I2aacce55d416abf2492631a504a02c6e8fc4ff1c
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

src/corelib/tools/qvector.cpp

@@ -338,6 +338,17 @@
     of \c operator<().
 */
 
+/*!
+    \fn uint qHash(const QVector<T> &key, uint seed = 0)
+    \since 5.6
+    \relates QVector
+
+    Returns the hash value for \a key,
+    using \a seed to seed the calculation.
+
+    This function requires qHash() to be overloaded for the value type \c T.
+*/
+
 /*! \fn int QVector::size() const
 
     Returns the number of items in the vector.

src/corelib/tools/qvector.h

@@ -39,6 +39,7 @@
 #include <QtCore/qlist.h>
 #include <QtCore/qrefcount.h>
 #include <QtCore/qarraydata.h>
+#include <QtCore/qhashfunctions.h>
 
 #include <iterator>
 #include <vector>
@@ -873,6 +874,13 @@ QList<T> QList<T>::fromVector(const QVector<T> &vector)
 Q_DECLARE_SEQUENTIAL_ITERATOR(Vector)
 Q_DECLARE_MUTABLE_SEQUENTIAL_ITERATOR(Vector)
 
+template <typename T>
+uint qHash(const QVector<T> &key, uint seed = 0)
+    Q_DECL_NOEXCEPT_EXPR(noexcept(qHashRange(key.cbegin(), key.cend(), seed)))
+{
+    return qHashRange(key.cbegin(), key.cend(), seed);
+}
+
 template <typename T>
 bool operator<(const QVector<T> &lhs, const QVector<T> &rhs)
     Q_DECL_NOEXCEPT_EXPR(noexcept(std::lexicographical_compare(lhs.begin(), lhs.end(),

tests/auto/corelib/tools/qvector/tst_qvector.cpp

@@ -86,6 +86,8 @@ private:
     }
 };
 
+inline uint qHash(const Movable &key, uint seed = 0) { return qHash(key.i, seed); }
+
 QAtomicInt Movable::counter = 0;
 QT_BEGIN_NAMESPACE
 Q_DECLARE_TYPEINFO(Movable, Q_MOVABLE_TYPE);
@@ -155,6 +157,8 @@ private:
 };
 QAtomicInt Custom::counter = 0;
 
+inline uint qHash(const Custom &key, uint seed = 0) { return qHash(key.i, seed); }
+
 Q_DECLARE_METATYPE(Custom);
 
 // tests depends on the fact that:
@@ -237,6 +241,9 @@ private slots:
     void prependInt() const;
     void prependMovable() const;
     void prependCustom() const;
+    void qhashInt() const { qhash<int>(); }
+    void qhashMovable() const { qhash<Movable>(); }
+    void qhashCustom() const { qhash<Custom>(); }
     void removeInt() const;
     void removeMovable() const;
     void removeCustom() const;
@@ -302,6 +309,7 @@ private:
     template<typename T> void fill() const;
     template<typename T> void fromList() const;
     template<typename T> void insert() const;
+    template<typename T> void qhash() const;
     template<typename T> void prepend() const;
     template<typename T> void remove() const;
     template<typename T> void size() const;
@@ -1445,6 +1453,16 @@ void tst_QVector::mid() const
     QCOMPARE(list.mid(4), QVector<QString>() << "buck" << "hello" << "kitty");
 }
 
+template <typename T>
+void tst_QVector::qhash() const
+{
+    QVector<T> l1, l2;
+    QCOMPARE(qHash(l1), qHash(l2));
+    l1 << SimpleValue<T>::at(0);
+    l2 << SimpleValue<T>::at(0);
+    QCOMPARE(qHash(l1), qHash(l2));
+}
+
 template<typename T>
 void tst_QVector::prepend() const
 {