-if (!is_array($crons) || $keys[0] > $local_time) {
- update_option('doing_cron', 0);
- return;
+if ( false === $crons = _get_cron_array() )
+ die();
+
+$keys = array_keys( $crons );
+$gmt_time = microtime( true );
+
+if ( isset($keys[0]) && $keys[0] > $gmt_time )
+ die();
+
+$doing_cron_transient = get_transient( 'doing_cron');
+
+// Use global $doing_wp_cron lock otherwise use the GET lock. If no lock, trying grabbing a new lock.
+if ( empty( $doing_wp_cron ) ) {
+ if ( empty( $_GET[ 'doing_wp_cron' ] ) ) {
+ // Called from external script/job. Try setting a lock.
+ if ( $doing_cron_transient && ( $doing_cron_transient + WP_CRON_LOCK_TIMEOUT > $gmt_time ) )
+ return;
+ $doing_cron_transient = $doing_wp_cron = sprintf( '%.22F', microtime( true ) );
+ set_transient( 'doing_cron', $doing_wp_cron );
+ } else {
+ $doing_wp_cron = $_GET[ 'doing_wp_cron' ];
+ }