[Development] Feature Freeze Exception: QStringView

[Александр Волков]

01.02.2017 17:22, Marc Mutz пишет:
> Ah, nevermind, 'found' is a QString_List_.
>
> I'm curious how a non-implicitly-shared string type would help you there,
> though. You can always clear() (or, in case of QVector<QString>, std::move())
> the string, and capacity is left with the sole owner in the container.

     QString s1;
     s1.reserve(1024);
     s1.resize(100, '*');
     qDebug() << s1.capacity(); // 1024

     QString s2 = s1;
     s1[0] = '-';
     qDebug() << s1.capacity(); // 100
     qDebug() << s2.capacity(); // 1024

With non-implicitly-shared string the capacity of s1 won't change.

The idea of readLineInto() is to avoid memory allocations by writing 
into the pre-allocated buffer.
But when readLineInto() is trying to write into an implicitly shared 
string buffer,
then the content of the buffer is copied and readLineInto() writes into 
the copy.