QFileSystemWatcher: fix quadratic loop by porting away from QMutableListIterator

QMutableListIterator::remove() is linear, so called in a loop, the
loop potentially becomes quadratic.

Fix by porting to std::remove_if. In this case, since the old code
unconditionally detached, anyway, we use remove_copy_if to build a new
list. That's still more efficient than the old code, even if nothing
is removed. It also prepares the code for when Java-style iterators
will be deprecated.

Since the same code appears in two different functions, do an Extract
Method into a file-static function.

Lastly, restore NRVO for most compilers by returning the same object
from all return statements of the function.

Change-Id: I6909c6483d8f7acfd1bf381828f020038b04e431
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
 
 
 
 
 
 
 

0 files changed, 0 insertions, 0 deletions