QMessageBox: optimize textToCopy string construction

1. Keep 'separator' a QLatin1String.
   - saves at least two memory allocations
   - necessitates carrying the \n previously prepended to it
     around explicitly
2. Start adding to 'textToCopy' with op+=
   - saves one allocation, costs one -> ±0
   - preallocates more capacity than if we started with
     assignment
3. Collapse three unconditional op+= into one
   - more efficient usage of QStringBuilder
4. Don't collect button texts in a separate variable, but
   append to 'textToCopy' directly.
   - saves at least one memory allocation, probably more
     since the growth increments of 'textToCopy' should
     be larger (due to more content) than those of a new
     variable.

Also replace index-based iteration over the buttons with
C++11 range-for over a const QList. Avoids the detach that
happened previously, due to use of op[] instead of at(),
but frankly, I was just too lazy to separate this change.

Change-Id: I27a46a6a163c16d773124f140e085325b17ce5d1
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>

0 files changed, 0 insertions, 0 deletions