Stop using setSharable in the Java-style mutable iterators

First and foremost, the STL-style iterators don't do this. Those don't
provide a guarantee that the container won't get shared again while the
iterator is active.

Second, there's no protection against a second mutable iterator being
created and resetting the sharable flag back to true.

[ChangeLog][Important behavior changes] The mutable Java-style iterators
like QListMutableIterator and QHashMutableIterator no longer set the
parent container to unsharable mode. If you create a copy of the
container being iterated on after the iterator, any changes done with
the iterator might affect the copy too.

Discussed-on: http://lists.qt-project.org/pipermail/development/2014-February/015724.html
Change-Id: Iccfe411d5558c85ae459cff944215614c392388e
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>

3 files changed, 6 insertions, 34 deletions

diff --git a/src/corelib/tools/qiterator.h b/src/corelib/tools/qiterator.h
index 3b86edd750..86b78eb522 100644
--- a/src/corelib/tools/qiterator.h
+++ b/src/corelib/tools/qiterator.h
@@ -87,12 +87,9 @@ class QMutable##C##Iterator \
 public: \
     inline QMutable##C##Iterator(Q##C<T> &container) \
         : c(&container) \
-    { c->setSharable(false); i = c->begin(); n = c->end(); } \
-    inline ~QMutable##C##Iterator() \
-    { c->setSharable(true); } \
+    { i = c->begin(); n = c->end(); } \
     inline QMutable##C##Iterator &operator=(Q##C<T> &container) \
-    { c->setSharable(true); c = &container; c->setSharable(false); \
-      i = c->begin(); n = c->end(); return *this; } \
+    { c = &container; i = c->begin(); n = c->end(); return *this; } \
     inline void toFront() { i = c->begin(); n = c->end(); } \
     inline void toBack() { i = c->end(); n = i; } \
     inline bool hasNext() const { return c->constEnd() != const_iterator(i); } \
@@ -160,11 +157,9 @@ class QMutable##C##Iterator \
 public: \
     inline QMutable##C##Iterator(Q##C<Key,T> &container) \
         : c(&container) \
-    { c->setSharable(false); i = c->begin(); n = c->end(); } \
-    inline ~QMutable##C##Iterator() \
-    { c->setSharable(true); } \
+    { i = c->begin(); n = c->end(); } \
     inline QMutable##C##Iterator &operator=(Q##C<Key,T> &container) \
-    { c->setSharable(true); c = &container; c->setSharable(false); i = c->begin(); n = c->end(); return *this; } \
+    { c = &container; i = c->begin(); n = c->end(); return *this; } \
     inline void toFront() { i = c->begin(); n = c->end(); } \
     inline void toBack() { i = c->end(); n = c->end(); } \
     inline bool hasNext() const { return const_iterator(i) != c->constEnd(); } \
diff --git a/src/corelib/tools/qiterator.qdoc b/src/corelib/tools/qiterator.qdoc
index 1ae9c58daa..f140af152d 100644
--- a/src/corelib/tools/qiterator.qdoc
+++ b/src/corelib/tools/qiterator.qdoc
@@ -501,17 +501,6 @@
     \sa operator=()
 */
 
-/*!
-    \fn QMutableListIterator::~QMutableListIterator()
-    \fn QMutableLinkedListIterator::~QMutableLinkedListIterator()
-    \fn QMutableVectorIterator::~QMutableVectorIterator()
-    \fn QMutableSetIterator::~QMutableSetIterator()
-
-    Destroys the iterator.
-
-    \sa operator=()
-*/
-
 /*! \fn QMutableListIterator &QMutableListIterator::operator=(QList<T> &list)
     \fn QMutableLinkedListIterator &QMutableLinkedListIterator::operator=(QLinkedList<T> &list)
     \fn QListIterator &QListIterator::operator=(const QList<T> &list)
@@ -1121,15 +1110,6 @@
     \sa operator=()
 */
 
-/*!
-    \fn QMutableMapIterator::~QMutableMapIterator()
-    \fn QMutableHashIterator::~QMutableHashIterator()
-
-    Destroys the iterator.
-
-    \sa operator=()
-*/
-
 /*! \fn QMapIterator &QMapIterator::operator=(const QMap<Key, T> &map)
     \fn QMutableMapIterator &QMutableMapIterator::operator=(QMap<Key, T> &map)
 
diff --git a/src/corelib/tools/qset.h b/src/corelib/tools/qset.h
index 992243def6..9682c97fec 100644
--- a/src/corelib/tools/qset.h
+++ b/src/corelib/tools/qset.h
@@ -356,12 +356,9 @@ class QMutableSetIterator
 public:
     inline QMutableSetIterator(QSet<T> &container)
         : c(&container)
-    { c->setSharable(false); i = c->begin(); n = c->end(); }
-    inline ~QMutableSetIterator()
-    { c->setSharable(true); }
+    { i = c->begin(); n = c->end(); }
     inline QMutableSetIterator &operator=(QSet<T> &container)
-    { c->setSharable(true); c = &container; c->setSharable(false);
-      i = c->begin(); n = c->end(); return *this; }
+    { c = &container; i = c->begin(); n = c->end(); return *this; }
     inline void toFront() { i = c->begin(); n = c->end(); }
     inline void toBack() { i = c->end(); n = i; }
     inline bool hasNext() const { return c->constEnd() != i; }