core-bundle/src/Resources/contao/drivers/DC_Folder.php
protected function isMounted($strFolder)
	{
		if ($strFolder == '')
		{
			return false;
		}

		if (empty($this->arrFilemounts))
		{
			return true;
		}

		$path = $strFolder;

		while (\is_array($this->arrFilemounts) && substr_count($path, '/') > 0)
		{
			if (\in_array($path, $this->arrFilemounts))
			{
				return true;
			}

			$path = \dirname($path);
		}

		return false;
	}
protected function isMounted($strFolder)
	{
		if ($strFolder == '')
		{
			return false;
		}

		if (empty($this->arrFilemounts))
		{
			return true;
		}

		$path = $strFolder;

		while (\is_array($this->arrFilemounts) && substr_count($path, '/') > 0)
		{
			if (\in_array($path, $this->arrFilemounts))
			{
				return true;
			}

			$path = \dirname($path);
		}

		return false;
	}
Return true if the current folder is mounted

@param string $strFolder

@return boolean