/**
* Wait for activity on one of several sockets.
*
* @param list List of sockets expected to become readable.
* @param list List of sockets expected to become writable.
* @param float Timeout, in seconds.
* @return void
*/
public static function waitForSockets(array $read_list, array $write_list, $timeout = 1)
{
if (!self::$handlerInstalled) {
// If we're spawning child processes, we need to install a signal handler
// here to catch cases like execing '(sleep 60 &) &' where the child
// exits but a socket is kept open. But we don't actually need to do
// anything because the SIGCHLD will interrupt the stream_select(), as
// long as we have a handler registered.
if (function_exists('pcntl_signal')) {
if (!pcntl_signal(SIGCHLD, array('Future', 'handleSIGCHLD'))) {
throw new Exception('Failed to install signal handler!');
}
}
self::$handlerInstalled = true;
}
$timeout_sec = (int) $timeout;
$timeout_usec = (int) (1000000 * ($timeout - $timeout_sec));
$exceptfds = array();
$ok = @stream_select($read_list, $write_list, $exceptfds, $timeout, $timeout_usec);
if ($ok === false) {
// Hopefully, means we received a SIGCHLD. In the worst case, we degrade
// to a busy wait.
}
}
