Centralize, rather than keeping adding constructors from any
array-like container.
A more robust implementation, likely following the converting
constructor for std::span ([span.cons]), is out of scope for C++17
and will require C++20's ranges and concepts.
[ChangeLog][QtCore][QStringView] QStringView can now be constructed
from any contiguous container, as long as they hold string-like data.
For instance, it's now possible to create a QStringView object
from a std::vector<char16_t>, a QVarLengthArray<ushort> and so on.
Change-Id: I7043eb194f617e98bd1f8af1237777a93a6c5e75
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
wchar_t hasn't been QStringView's storage_type for a very long time
(at least since 5.10). And in Qt 6, we require char16_t support not
only in the compiler, but also in the stdlib, so drop the guards and
the alternative code paths.
Change-Id: I99f28b575f61c16a2497840708beaa4b54a80f57
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
They don't work with std::span, since std::span has neither
const_iterator nor cbegin()/cend().
To fix, perfectly forward the return type with decltype(auto) instead
of mentioning T::const_iterator, and rely on the const-qualfication of
the help::c{r,}{begin,end}() functions' arguments to select the
correct T::{r,}{begin,end}() overload.
Change-Id: I4992d4bd521d2dc0f9ea51ae70cde8286ae543a5
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
In the presence of multiple overloads of a function taking either
QString or QStringView, QStringView should always be preferred.
The rationale is that the QStringView overload may have been
added "later" (read: the function was written when QStringView
was not available yet, so it took QString), and the fact that
a function with the _same name_ offers a QStringView overload
implies the function never needed to store/own the string in
the first place.
Add a (compile-time) test for this preference. This is in
preparation for a future QString(char16_t*) constructor
(in Qt 5.15 / Qt 6).
Change-Id: I60a435e494b653548f8f8d52c5d7e7cac2cc875a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
As a macro, we can't directly deprecate it, but need to make it call
something deprecated. That is a new ctor with a new enum type
added. The type might be useful for other such ventures, so put it
into qglobal.h
Remove the QT_NO_UNICODE_LITERAL protection, as it's always false
these days, and QT_UNICODE_LITERAL is unconditionally #defined a 20
lines above.
[ChangeLog][QtCore][QStringView] Deprecated the (undocumented)
QStringViewLiteral macro. Just use u"" or QStringView(u"") instead.
Change-Id: I9141320225037e1bc6b7f920bf01a9d0144fdac2
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Now that all our supported compilers know char16_t, we no longer need
QStringViewLiteral, whose only purpose in life was to turn u"" into
L"" for MSVC < 2015.
Change-Id: I25a094fe7992d9d5dbeb4a524d9e99e043dcb8ce
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
