diff options
author | Olivier Goffart <ogoffart@woboq.com> | 2014-07-03 13:38:59 +0200 |
---|---|---|
committer | Olivier Goffart <ogoffart@woboq.com> | 2014-07-08 16:13:17 +0200 |
commit | 813af5f0655c332b2853d156b91c5265b85cbc70 (patch) | |
tree | e5d7337b93fbf436dc5b8e811de19cae752681b4 /src/corelib/tools | |
parent | 84e189502ac5849d89dedff491b1a5d9c5de793e (diff) |
Remove QHashDummyNode and avoid undifined behavior
A lot of code in QHash is doing casting to QHashNode while the pointer
may be of type QHashDummyNode. This is a lot of undefined behavior.
Remove QHashDummyNode and specialize QHashNode for QHashDummyValue instead.
QHashDummyValue is the only type for which QTypeInfo::isDummy is true.
Q_DUMMY and QTypeInfo::isDummy are internal API, so is QHashDummyNode, so
we can remove them.
Task-number: QTBUG-40029
Change-Id: I60c2ff0933075b9202bde89a9992746052f75133
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib/tools')
-rw-r--r-- | src/corelib/tools/qhash.h | 41 |
1 files changed, 16 insertions, 25 deletions
diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h index 1d76a2b3d1..db2d084035 100644 --- a/src/corelib/tools/qhash.h +++ b/src/corelib/tools/qhash.h @@ -217,17 +217,23 @@ private: Q_DISABLE_COPY(QHashNode) }; -template <class Key, class T> -struct QHashDummyNode +// Specialize for QHashDummyValue in order to save some memory +template <class Key> +struct QHashNode<Key, QHashDummyValue> { - QHashNode<Key, T> *next; + union { + QHashNode *next; + QHashDummyValue value; + }; const uint h; const Key key; - inline QHashDummyNode(const Key &key0, uint hash, QHashNode<Key, T> *n) : next(n), h(hash), key(key0) {} + inline QHashNode(const Key &key0, const QHashDummyValue &, uint hash, QHashNode *n) + : next(n), h(hash), key(key0) {} + inline bool same_key(uint h0, const Key &key0) const { return h0 == h && key0 == key; } private: - Q_DISABLE_COPY(QHashDummyNode) + Q_DISABLE_COPY(QHashNode) }; @@ -276,7 +282,6 @@ Q_HASH_DECLARE_INT_NODES(uint); template <class Key, class T> class QHash { - typedef QHashDummyNode<Key, T> DummyNode; typedef QHashNode<Key, T> Node; union { @@ -289,7 +294,6 @@ class QHash } static inline int alignOfNode() { return qMax<int>(sizeof(void*), Q_ALIGNOF(Node)); } - static inline int alignOfDummyNode() { return qMax<int>(sizeof(void*), Q_ALIGNOF(DummyNode)); } public: inline QHash() : d(const_cast<QHashData *>(&QHashData::shared_null)) { } @@ -554,25 +558,14 @@ template <class Key, class T> Q_INLINE_TEMPLATE void QHash<Key, T>::duplicateNode(QHashData::Node *node, void *newNode) { Node *concreteNode = concrete(node); - if (QTypeInfo<T>::isDummy) { - (void) new (newNode) DummyNode(concreteNode->key, concreteNode->h, 0); - } else { - (void) new (newNode) Node(concreteNode->key, concreteNode->value, concreteNode->h, 0); - } + new (newNode) Node(concreteNode->key, concreteNode->value, concreteNode->h, 0); } template <class Key, class T> Q_INLINE_TEMPLATE typename QHash<Key, T>::Node * QHash<Key, T>::createNode(uint ah, const Key &akey, const T &avalue, Node **anextNode) { - Node *node; - - if (QTypeInfo<T>::isDummy) { - node = reinterpret_cast<Node *>(new (d->allocateNode(alignOfDummyNode())) DummyNode(akey, ah, *anextNode)); - } else { - node = new (d->allocateNode(alignOfNode())) Node(akey, avalue, ah, *anextNode); - } - + Node *node = new (d->allocateNode(alignOfNode())) Node(akey, avalue, ah, *anextNode); *anextNode = node; ++d->size; return node; @@ -605,9 +598,7 @@ Q_INLINE_TEMPLATE void QHash<Key, T>::clear() template <class Key, class T> Q_OUTOFLINE_TEMPLATE void QHash<Key, T>::detach_helper() { - QHashData *x = d->detach_helper(duplicateNode, deleteNode2, - QTypeInfo<T>::isDummy ? sizeof(DummyNode) : sizeof(Node), - QTypeInfo<T>::isDummy ? alignOfDummyNode() : alignOfNode()); + QHashData *x = d->detach_helper(duplicateNode, deleteNode2, sizeof(Node), alignOfNode()); if (!d->ref.deref()) freeData(d); d = x; @@ -789,7 +780,7 @@ Q_INLINE_TEMPLATE typename QHash<Key, T>::iterator QHash<Key, T>::insert(const K return iterator(createNode(h, akey, avalue, node)); } - if (!QTypeInfo<T>::isDummy) + if (!QtPrivate::is_same<T, QHashDummyValue>::value) (*node)->value = avalue; return iterator(*node); } @@ -958,7 +949,7 @@ Q_OUTOFLINE_TEMPLATE bool QHash<Key, T>::operator==(const QHash<Key, T> &other) do { if (it2 == other.end() || !(it2.key() == akey)) return false; - if (!QTypeInfo<T>::isDummy && !(it.value() == it2.value())) + if (!(it.value() == it2.value())) return false; ++it; ++it2; |