Determine expiration time in the cache table of the cache type or CACHE_PERMANENT if item shouldn't be removed automatically from cache.
Plugins must override this to implement expiration in the cache table.
$type: The cache type, either 'query', 'result' or 'output'.
Overrides CachePluginBase::cacheSetExpire
protected function cacheSetExpire($type) {
$lifespan = $this
->getLifespan($type);
if ($lifespan) {
return time() + $lifespan;
}
else {
return CacheBackendInterface::CACHE_PERMANENT;
}
}