protected function checkEnvironment()
    {
        // Check chunk folder is writable.
        // If not, give feedback!
        $chunkFolder = $this->config->getChunkDir();
        if (is_writeable($chunkFolder) === false) {
            $chunkFolder = $this->fileService->filterFilePath($chunkFolder);
            $this->messages->addMessage('chunksNotWritable', array($chunkFolder));
            // We can work without chunks, but this will require much more memory!
            $this->chunks->setUseChunks(false);
        }

        // Check if the log folder is writable.
        // If not, give feedback!
        $logFolder = $this->config->getLogDir();
        if (is_writeable($logFolder) === false) {
            $logFolder = $this->fileService->filterFilePath($logFolder);
            $this->messages->addMessage('logNotWritable', array($logFolder));
            // Tell the chunk output that we have no write access in the logging
            // folder.
            $this->chunks->setUseLogging(false);
        }

        // At this point, we won't inform the dev right away. The error message
        // will pop up, when kreXX is actually displayed, no need to bother the
        // dev just now.
    }