[Development] Feature Freeze Exception: QStringView

[Kevin Kofler]

Marc Mutz wrote:
> QStringLiteral is not what most people use. It's too verbose.

#define U(x) QStringLiteral(x)
or some other 1-letter macro or even $ (which most compilers will let you 
get away with).

> They use "&OK",

We really need a plan to deprecate implicit casts between QString and ASCII. 
They are not only the source of such inefficiencies from inexperienced or 
lazy programmers, but also of encoding-related bugs. If you need to convert 
between 8-bit encodings and QString, you should always use a function that 
specifies the correct encoding for the context (e.g. fromLocal8Bit). If your 
string is constant, you should use QStringLiteral.

> and if we hopefully get SSO, QStringView-setter overhead will be greatly
> reduced.

The overhead compared to using QString will be reduced, but only part of it 
(the avoided memory allocation) is really an optimization. The rest of the 
"reduced" overhead is because QString will get the same overhead bloated 
onto it (copying the entire string). So, sure, technically, QStringView will 
have less overhead over QString, but the way you achieved that is 
counterproductive. And all this is only valid for very short strings, longer 
strings will still behave the same as before, except for the overhead of the 
unused SSO array in both cases.

        Kevin Kofler