QtBase: avoid uses of Java-style iterators [QHash, QMap]

Java-style iterators are slower than STL-style ones, so
they should not be used in library code.

Replaced them with C++11 range-for, STL iterators or, in
one case, qDeleteAll().

In one case, avoid a double hash lookup by using erase(it)
instead of remove(it.key()), which we can now do without
detaching, due to the new erase() taking const_iterator.

Change-Id: I96174657fed70f76120b2c9d8190b4e70d5d8179
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/src/widgets/itemviews/qcolumnview.cpp b/src/widgets/itemviews/qcolumnview.cpp
index bc8a9d38d8..cba7e8aacc 100644
--- a/src/widgets/itemviews/qcolumnview.cpp
+++ b/src/widgets/itemviews/qcolumnview.cpp
@@ -793,11 +793,8 @@ void QColumnView::initializeColumn(QAbstractItemView *column) const
     column->setModel(model());
 
     // Copy the custom delegate per row
-    QMapIterator<int, QPointer<QAbstractItemDelegate> > i(d->rowDelegates);
-    while (i.hasNext()) {
-        i.next();
+    for (auto i = d->rowDelegates.cbegin(), end = d->rowDelegates.cend(); i != end; ++i)
         column->setItemDelegateForRow(i.key(), i.value());
-    }
 
     // set the delegate to be the columnview delegate
     QAbstractItemDelegate *delegate = column->itemDelegate();