Retrieves the current batch.
function &batch_get() {
// Not drupal_static(), because Batch API operates at a lower level than most
// use-cases for resetting static variables, and we specifically do not want a
// global drupal_static_reset() resetting the batch information. Functions
// that are part of the Batch API and need to reset the batch information may
// call batch_get() and manipulate the result by reference. Functions that are
// not part of the Batch API can also do this, but shouldn't.
static $batch = array();
return $batch;
}