/**
* Hashes a descriptive key to make it shorter and still unique.
* @param string|int $key
* @param cache_definition $definition
* @return string
*/
public static function hash_key($key, cache_definition $definition)
{
if ($definition->uses_simple_keys()) {
if (debugging() && preg_match('#[^a-zA-Z0-9_]#', $key)) {
throw new coding_exception('Cache definition ' . $definition->get_id() . ' requires simple keys. Invalid key provided.', $key);
}
// We put the key first so that we can be sure the start of the key changes.
return (string) $key . '-' . $definition->generate_single_key_prefix();
}
$key = $definition->generate_single_key_prefix() . '-' . $key;
return sha1($key);
}