private function filterBodyNodes(Twig_Node $node)
{
// check that the body does not contain non-empty output nodes
if ($node instanceof Twig_Node_Text && !ctype_space($node->getAttribute('data')) || !$node instanceof Twig_Node_Text && !$node instanceof Twig_Node_BlockReference && $node instanceof Twig_NodeOutputInterface) {
if (false !== strpos((string) $node, chr(0xef) . chr(0xbb) . chr(0xbf))) {
throw new Twig_Error_Syntax('A template that extends another one cannot start with a byte order mark (BOM); it must be removed.', $node->getLine(), $this->getFilename());
}
throw new Twig_Error_Syntax('A template that extends another one cannot include contents outside Twig blocks. Did you forget to put the contents inside a {% block %} tag?', $node->getLine(), $this->getFilename());
}
// bypass "set" nodes as they "capture" the output
if ($node instanceof Twig_Node_Set) {
return $node;
}
if ($node instanceof Twig_NodeOutputInterface) {
return;
}
foreach ($node as $k => $n) {
if (null !== $n && null === $this->filterBodyNodes($n)) {
$node->removeNode($k);
}
}
return $node;
}
