Function foreach

src/master/maintenance.cpp:51–57

  // Put the machines in the existing schedule into a set.
  hashset<MachineID> existing;
  foreach (const maintenance::Schedule& agenda, registry->schedules()) {
    foreach (const maintenance::Window& window, agenda.windows()) {
      foreach (const MachineID& id, window.machine_ids()) {
        existing.insert(id);
      }
    }
  }

  // Put the machines in the updated schedule into a set.
  // Keep the relevant unavailability to help update existing machines.