diff options
author | Marc Mutz <marc.mutz@kdab.com> | 2014-08-09 21:25:57 +0200 |
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committer | Marc Mutz <marc.mutz@kdab.com> | 2014-08-26 09:07:25 +0200 |
commit | 2d4954810bbfe22a38fea8cb056f4961e4e524b3 (patch) | |
tree | ba7dbc22c5b2ffb98e719b6b95d61da2a075360f /src/widgets/itemviews/qdatawidgetmapper.cpp | |
parent | 1c73a237cebe5ed0fb975cb33133316b278b9c9e (diff) |
QDataWidgetMapper: micro-optimize clearMapping()
QList<WidgetMapper>::takeLast() is a needlessly expensive operation
(involves copying a QPersistentModelIndex and a QPointer).
Instead of looping over takeLast() until empty, reverse-iterate
over the list and call removeEventFilter(), then clear the whole
list.
We reverse-iterate to preserve existing behavior. Also, since the
original code popped the WidgetMapper instance before calling
removeEventFilter(), we move the whole list into a local copy
before iterating. There's little chance that a removeEventFilter()
call will cause reentrancy into QDataWidgetMapper, but better safe
than sorry.
This and the previous change together save 448 bytes of text size in
libQt5Widgets.
Change-Id: I1bfe907751659f31e618aa05bbb7b840f0aa61f4
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Diffstat (limited to 'src/widgets/itemviews/qdatawidgetmapper.cpp')
-rw-r--r-- | src/widgets/itemviews/qdatawidgetmapper.cpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/widgets/itemviews/qdatawidgetmapper.cpp b/src/widgets/itemviews/qdatawidgetmapper.cpp index 8b9d6f9d6c..4158e00dfc 100644 --- a/src/widgets/itemviews/qdatawidgetmapper.cpp +++ b/src/widgets/itemviews/qdatawidgetmapper.cpp @@ -762,10 +762,11 @@ void QDataWidgetMapper::clearMapping() { Q_D(QDataWidgetMapper); - while (!d->widgetMap.isEmpty()) { - QWidget *w = d->widgetMap.takeLast().widget; - if (w) - w->removeEventFilter(d->delegate); + QList<QDataWidgetMapperPrivate::WidgetMapper> copy; + d->widgetMap.swap(copy); // a C++98 move + for (std::reverse_iterator<QList<QDataWidgetMapperPrivate::WidgetMapper>::const_iterator> it(copy.cend()), end(copy.cbegin()); it != end; ++it) { + if (it->widget) + it->widget->removeEventFilter(d->delegate); } } |