QTranslator: Extract Method is_readable_file from find_translation()

The old code re-used a QFileInfo object, repeatedly
setting new file names with QFileInfo::setFile(QString).

But QFileInfo::setFile() simply assigns itself a
new QFileInfo object:
    *this = QFileInfo(...)
so it's just as efficient to re-create a new QFIleInfo
object for every file name under test.

To avoid extra {} for object lifetime scoping, factor
the repeated evaluation of isReadable() && isFile()
into a small helper function, which also creates and
destroys the QFileInfo object.

The deeper significance of this change is that it
avoids implicit sharing of 'realname', which is
permanently modified. A later patch will make
changes that make 'realname' re-use its capacity
through the lifetime of the find_translation()
function, and sharing the variable implicitly will
nip any auch attempts in the bud.

Force the compiler to not inline the new function.
There's really no point in spending ~0.5KiB in text
size on inlining the code; the miniscule speed
improvement is dwarfed by the memory allocation of
the QFileInfo ctor, anyway.

As a consequence, this change even saves 96b in text
size on optimized GCC 4.9 Linux AMD64 builds, even
though that wasn't even the goal.

Change-Id: I08c5cbb7b6f1ba59440a1597e28d962ce63a7c65
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions