function d8cache_root_transaction_end in Drupal 8 Cache Backport 7

Callback to invalidate cache tags at the end of a transaction.

1 string reference to 'd8cache_root_transaction_end'

d8cache_invalidate_cache_tags in ./d8cache.module

Implements hook_invalidate_cache_tags().

File

./d8cache.module, line 193

Main module file for the D8 caching system backport.

Code

function d8cache_root_transaction_end($committed = NULL) {
  $deferred_tags =& drupal_static('d8cache_deferred_tags', array());
  if ($committed === NULL || $committed === TRUE) {

    // If the commit is presumed successful, proceed with the invalidation.
    d8cache_do_invalidate_cache_tags(array_keys($deferred_tags));
  }
  else {

    // Since the transaction was rolled back, the deferred tags no longer
    // match reality. Since the end result of this transaction was nothing,
    // we should also do nothing, to eliminate side effects.
    // Whatever transaction beat us to the commit will have also done its
    // own invalidation as appropriate, and attempting to invalidate
    // things ourselves will just cause additional contention for no reason.
    // Therefore, we do not want to act on the deferred tags at all.
    //
    // @todo Check transaction isolation level and invalidate anyway if the
    // database is operating in a non-isolated mode?
  }

  // In both cases, we reset the deferred_tags list.
  $deferred_tags = array();
}