From 1173d0420e341dc6d38c89e5bc4295a57da7ea74 Mon Sep 17 00:00:00 2001
From: "Bradley T. Hughes" <bradley.hughes@nokia.com>
Date: Fri, 9 Sep 2011 11:18:28 +0200
Subject: Make QHashData::shared_null const

Similar to QLinkedList QList, QMap, QVector, QByteArray and QString,
keep the shared_null in shareable memory and never modify it.

Change-Id: Ia8b72ef0288575bed658153d9d54434580988bda
Reviewed-on: http://codereview.qt-project.org/4533
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
---
 src/corelib/tools/qhash.cpp | 4 ++--
 src/corelib/tools/qhash.h   | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/corelib/tools/qhash.cpp b/src/corelib/tools/qhash.cpp
index f43e888b61..2e60f40a9c 100644
--- a/src/corelib/tools/qhash.cpp
+++ b/src/corelib/tools/qhash.cpp
@@ -165,8 +165,8 @@ static int countBits(int hint)
 */
 const int MinNumBits = 4;
 
-QHashData QHashData::shared_null = {
-    0, 0, Q_BASIC_ATOMIC_INITIALIZER(1), 0, 0, MinNumBits, 0, 0, true, false, 0
+const QHashData QHashData::shared_null = {
+    0, 0, Q_REFCOUNT_INITIALIZER(-1), 0, 0, MinNumBits, 0, 0, true, false, 0
 };
 
 void *QHashData::allocateNode()
diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 55c3efa307..40a58fdbf8 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -42,11 +42,11 @@
 #ifndef QHASH_H
 #define QHASH_H
 
-#include <QtCore/qatomic.h>
 #include <QtCore/qchar.h>
 #include <QtCore/qiterator.h>
 #include <QtCore/qlist.h>
 #include <QtCore/qpair.h>
+#include <QtCore/qrefcount.h>
 
 QT_BEGIN_HEADER
 
@@ -118,7 +118,7 @@ struct Q_CORE_EXPORT QHashData
 
     Node *fakeNext;
     Node **buckets;
-    QBasicAtomicInt ref;
+    QtPrivate::RefCount ref;
     int size;
     int nodeSize;
     short userNumBits;
@@ -148,7 +148,7 @@ struct Q_CORE_EXPORT QHashData
     static Node *nextNode(Node *node);
     static Node *previousNode(Node *node);
 
-    static QHashData shared_null;
+    static const QHashData shared_null;
 };
 
 inline void QHashData::mightGrow() // ### Qt 5: eliminate
@@ -278,7 +278,7 @@ class QHash
 #endif
 
 public:
-    inline QHash() : d(&QHashData::shared_null) { d->ref.ref(); }
+    inline QHash() : d(const_cast<QHashData *>(&QHashData::shared_null)) { }
     inline QHash(const QHash<Key, T> &other) : d(other.d) { d->ref.ref(); if (!d->sharable) detach(); }
     inline ~QHash() { if (!d->ref.deref()) freeData(d); }
 
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