/**
* Schedule $callable for delayed execution.
*
* $callable will be executed after the response has been sent to the client.
* This is useful for expensive operations which do not need to send
* anything to the client.
*
* At the first call to defer, deferring will be "activated". This means that
* output buffering is enabled, keepalive disabled and user-abort is ignored.
* You can check to see if deferring is enabled by doing a truth check on
* gb::$deferred. The event "did-activate-deferring" is also posted.
*
* Use deferring wth caution.
*
* A good example of when delayed execution is a good idea, is how the
* email-notification plugin defers the mail action (this is actually part of
* GBMail but this plugin makes good use of it).
*
* Events:
*
* - "did-activate-deferring"
* Posted when defer is activated.
*
*/
static function defer($callable)
{
if (self::$deferred === null) {
if (headers_sent()) {
return false;
}
ob_start();
header('Transfer-Encoding: identity');
header('Connection: close');
self::$deferred = array();
register_shutdown_function(array('gb', 'run_deferred'));
ignore_user_abort(true);
gb::event('did-activate-deferring');
}
self::$deferred[] = array($callable, array_slice(func_get_args(), 1));
return true;
}