Generate a new DBFile instance using the given callback if it hasn't been created yet, or return the existing one if it has.
Signature
public function manipulate(string
$variant,
callable
$callback )
Parameters
$variant
—
string
name of the variant to create
$callback
—
object
Callback which should return a new tuple as an array. This callback will be passed the backend, filename, hash, and variant This will not be called if the file does not need to be created.