D17028: Loader: Avoid Q_FOREACH

[loh tar]

loh.tar added inline comments.

INLINE COMMENTS

> davidedmundson wrote in loader.cpp:273
> > Probably, yes. But Qt docu always says, "thanks to implicit sharing copying a container is very fast"
> 
> That's mixing up docs.
> 
> foreach() always does a const copy of the list. This is a cheap implicitly shared copy.
> when we loop we're never detaching this list because it's const.
> 
> for() does not
> So when we loop if we call begin() we might get the non-const version. If this list is used elsewhere that means we detach and that causes a deep-copy. This is expensive.
> 
> In this specific case language() returns a new QStringList (.keys() generates a new list) so I /think/ it is fine,
> 
> but it's definitely ambiguous. A qAsConst would make sense here.

> A qAsConst would make sense here.

In which way? This is not working:

  for (const QString &langCode : qAsConst(languages()))

So you like to see this?

  const QStringList constLanguages = languages();
  for (const QString &langCode : constLanguages) {

REPOSITORY
  R246 Sonnet

REVISION DETAIL
  https://phabricator.kde.org/D17028

To: loh.tar, davidedmundson
Cc: smartins, kde-frameworks-devel, michaelh, ngraham, bruns
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