class vfsStreamPrintVisitor

class vfsStreamPrintVisitor extends vfsStreamAbstractVisitor {
    
    /**
     * target to write output to
     *
     * @type  resource
     */
    protected $out;
    
    /**
     * current depth in directory tree
     *
     * @type  int
     */
    protected $depth;
    
    /**
     * constructor
     *
     * If no file pointer given it will fall back to STDOUT.
     *
     * @param   resource  $out  optional
     * @throws  \InvalidArgumentException
     * @api
     */
    public function __construct($out = STDOUT) {
        if (is_resource($out) === false || get_resource_type($out) !== 'stream') {
            throw new \InvalidArgumentException('Given filepointer is not a resource of type stream');
        }
        $this->out = $out;
        $this->depth = 0;
    }
    
    /**
     * visit a file and process it
     *
     * @param   vfsStreamFile  $file
     * @return  vfsStreamPrintVisitor
     */
    public function visitFile(vfsStreamFile $file) {
        $this->printContent($file->getName());
        return $this;
    }
    
    /**
     * visit a block device and process it
     *
     * @param   vfsStreamBlock  $block
     * @return  vfsStreamPrintVisitor
     */
    public function visitBlockDevice(vfsStreamBlock $block) {
        $name = '[' . $block->getName() . ']';
        $this->printContent($name);
        return $this;
    }
    
    /**
     * visit a directory and process it
     *
     * @param   vfsStreamDirectory  $dir
     * @return  vfsStreamPrintVisitor
     */
    public function visitDirectory(vfsStreamDirectory $dir) {
        $this->printContent($dir->getName());
        $this->depth++;
        foreach ($dir as $child) {
            $this->visit($child);
        }
        $this->depth--;
        return $this;
    }
    
    /**
     * helper method to print the content
     *
     * @param  string   $name
     */
    protected function printContent($name) {
        fwrite($this->out, str_repeat('  ', $this->depth) . '- ' . $name . "\n");
    }

}