/**
* Create connection, with built-in pool.
* @param string $conn connection string, like `protocal://host:port`.
* @param mixed $arg external argument, fetched by `[[getExArg()]]`
* @return static the connection object, null if it reaches the upper limit of concurrent, or false on failure.
*/
public static function connect($conn, $arg = null)
{
$obj = null;
if (!isset(self::$_objs[$conn])) {
self::$_objs[$conn] = [];
}
foreach (self::$_objs[$conn] as $tmp) {
if (!($tmp->flag & self::FLAG_BUSY)) {
Client::debug('reuse conn \'', $tmp->conn, '\': ', $tmp->sock);
$obj = $tmp;
break;
}
}
if ($obj === null && count(self::$_objs[$conn]) < self::MAX_BURST) {
$obj = new self($conn);
self::$_objs[$conn][] = $obj;
Client::debug('create conn \'', $conn, '\'');
}
if ($obj !== null) {
if ($obj->flag & self::FLAG_OPENED) {
$obj->flag |= self::FLAG_REUSED;
} else {
if (!$obj->openSock()) {
return false;
}
}
$obj->flag |= self::FLAG_BUSY;
$obj->outBuf = null;
$obj->outLen = 0;
$obj->arg = $arg;
}
return $obj;
}
