From 5fdc64f5666d094e34e1373e75ae6e50239d9622 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Wed, 8 Apr 2015 19:44:48 +0200
Subject: [PATCH] Add qHash(QList)

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

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

Change-Id: I9ad91811f12479764cc17d87192539612ceb0b4c
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
---
 src/corelib/tools/qlist.cpp                  | 11 +++++++++++
 src/corelib/tools/qlist.h                    |  8 ++++++++
 tests/auto/corelib/tools/qlist/tst_qlist.cpp | 14 ++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/src/corelib/tools/qlist.cpp b/src/corelib/tools/qlist.cpp
index 126147716c..f4901d336e 100644
--- a/src/corelib/tools/qlist.cpp
+++ b/src/corelib/tools/qlist.cpp
@@ -632,6 +632,17 @@ void **QListData::erase(void **xi)
     of \c operator<().
 */
 
+/*!
+    \fn uint qHash(const QList<T> &key, uint seed = 0)
+    \since 5.6
+    \relates QList
+
+    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 QList::size() const
 
diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index 34ebedce3b..85e4570f45 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -38,6 +38,7 @@
 #include <QtCore/qiterator.h>
 #include <QtCore/qrefcount.h>
 #include <QtCore/qarraydata.h>
+#include <QtCore/qhashfunctions.h>
 
 #include <iterator>
 #include <list>
@@ -1021,6 +1022,13 @@ inline int QList<T>::count_impl(const T &t, QListData::ArrayCompatibleLayout) co
 Q_DECLARE_SEQUENTIAL_ITERATOR(List)
 Q_DECLARE_MUTABLE_SEQUENTIAL_ITERATOR(List)
 
+template <typename T>
+uint qHash(const QList<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 QList<T> &lhs, const QList<T> &rhs)
     Q_DECL_NOEXCEPT_EXPR(noexcept(std::lexicographical_compare(lhs.begin(), lhs.end(),
diff --git a/tests/auto/corelib/tools/qlist/tst_qlist.cpp b/tests/auto/corelib/tools/qlist/tst_qlist.cpp
index 9b12083b18..dd9371fbe1 100644
--- a/tests/auto/corelib/tools/qlist/tst_qlist.cpp
+++ b/tests/auto/corelib/tools/qlist/tst_qlist.cpp
@@ -399,6 +399,9 @@ private slots:
     void eraseValidIteratorsOnSharedList() const;
     void insertWithValidIteratorsOnSharedList() const;
 
+    void qhashOptimal() const { qhash<Optimal>(); }
+    void qhashMovable() const { qhash<Movable>(); }
+    void qhashComplex() const { qhash<Complex>(); }
     void reserve() const;
 private:
     template<typename T> void length() const;
@@ -415,6 +418,7 @@ private:
     template<typename T> void endsWith() const;
     template<typename T> void lastIndexOf() const;
     template<typename T> void move() const;
+    template<typename T> void qhash() const;
     template<typename T> void removeAll() const;
     template<typename T> void removeAt() const;
     template<typename T> void removeOne() const;
@@ -1908,6 +1912,16 @@ void tst_QList::insertWithValidIteratorsOnSharedList() const
     QCOMPARE(a.at(1), 15);
 }
 
+template <typename T>
+void tst_QList::qhash() const
+{
+    QList<T> l1, l2;
+    QCOMPARE(qHash(l1), qHash(l2));
+    l1 << T_BAR;
+    l2 << T_BAR;
+    QCOMPARE(qHash(l1), qHash(l2));
+}
+
 void tst_QList::reserve() const
 {
     // Note: