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QMap: don't dereference nullptr II

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root(), leftNode() and rightNode() can be nullptr.
These pieces of code happened to work because the first thing lowerBound()
does is

   Node *n = this;
   // ...
   while (n)
     // ...

But that is _after_ dereferencing nullptr, which is undefined behavior.

So, check first, then deref.

This is the completion of I9137bf6e21014cd68404a7e49a748910b1d768cf:
all uses of root(), leftNode() and rightNode() have now been manually checked.

Change-Id: I3fcb958af9362104f94d6eea9c62da2ae07f1d5e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Marc Mutz 2013-09-15 18:51:36 +02:00 committed by The Qt Project
parent 250190b39b
commit bcb68461c9
1 changed files with 4 additions and 4 deletions
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8
src/corelib/tools/qmap.h
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@ -1054,7 +1054,7 @@ Q_OUTOFLINE_TEMPLATE QList<T> QMap<Key, T>::values(const Key &akey) const
template <class Key, class T> template <class Key, class T>
Q_INLINE_TEMPLATE typename QMap<Key, T>::const_iterator QMap<Key, T>::lowerBound(const Key &akey) const Q_INLINE_TEMPLATE typename QMap<Key, T>::const_iterator QMap<Key, T>::lowerBound(const Key &akey) const
{ {
Node *lb = d->root()->lowerBound(akey); Node *lb = d->root() ? d->root()->lowerBound(akey) : 0;
if (!lb) if (!lb)
lb = d->end(); lb = d->end();
return const_iterator(lb); return const_iterator(lb);
@ -1064,7 +1064,7 @@ template <class Key, class T>
Q_INLINE_TEMPLATE typename QMap<Key, T>::iterator QMap<Key, T>::lowerBound(const Key &akey) Q_INLINE_TEMPLATE typename QMap<Key, T>::iterator QMap<Key, T>::lowerBound(const Key &akey)
{ {
detach(); detach();
Node *lb = d->root()->lowerBound(akey); Node *lb = d->root() ? d->root()->lowerBound(akey) : 0;
if (!lb) if (!lb)
lb = d->end(); lb = d->end();
return iterator(lb); return iterator(lb);
@ -1074,7 +1074,7 @@ template <class Key, class T>
Q_INLINE_TEMPLATE typename QMap<Key, T>::const_iterator Q_INLINE_TEMPLATE typename QMap<Key, T>::const_iterator
QMap<Key, T>::upperBound(const Key &akey) const QMap<Key, T>::upperBound(const Key &akey) const
{ {
Node *ub = d->root()->upperBound(akey); Node *ub = d->root() ? d->root()->upperBound(akey) : 0;
if (!ub) if (!ub)
ub = d->end(); ub = d->end();
return const_iterator(ub); return const_iterator(ub);
@ -1084,7 +1084,7 @@ template <class Key, class T>
Q_INLINE_TEMPLATE typename QMap<Key, T>::iterator QMap<Key, T>::upperBound(const Key &akey) Q_INLINE_TEMPLATE typename QMap<Key, T>::iterator QMap<Key, T>::upperBound(const Key &akey)
{ {
detach(); detach();
Node *ub = d->root()->upperBound(akey); Node *ub = d->root() ? d->root()->upperBound(akey) : 0;
if (!ub) if (!ub)
ub = d->end(); ub = d->end();
return iterator(ub); return iterator(ub);