void ms::SurfaceStack::raise(SurfaceSet const& ss)
{
bool surfaces_reordered{false};
{
std::lock_guard<decltype(guard)> ul(guard);
auto const old_surfaces = surfaces;
std::stable_partition(
begin(surfaces), end(surfaces),
[&](std::weak_ptr<Surface> const& s) { return !ss.count(s); });
if (old_surfaces != surfaces)
surfaces_reordered = true;
}
if (surfaces_reordered)
observers.surfaces_reordered();
}
