DOMPostOrder.php
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DOMPostOrder.php
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	<?php
	declare( strict_types = 1 );

	namespace Wikimedia\Parsoid\Utils;

	use Wikimedia\Parsoid\DOM\Node;

	/**
	* Non-recursive post-order traversal of a DOM tree.
	*/
	class DOMPostOrder {
	/**
	* @suppress PhanEmptyPrivateMethod
	*/
	private function __construct() {
	/* Not meant to be instantiated. */
	}

	/**
	* Non-recursive post-order traversal of a DOM tree.
	* @param Node $root
	* @param callable $visitFunc Called in post-order on each node.
	*/
	public static function traverse( Node $root, callable $visitFunc ): void {
	$node = $root;
	while ( true ) {
	// Find leftmost (grand)child, and visit that first.
	while ( $node->firstChild ) {
	$node = $node->firstChild;
	}
	while ( true ) {
	$visitFunc( $node );
	if ( $node === $root ) {
	return; // Visiting the root is the last thing we do.
	}
	/* Look for right sibling to continue traversal. */
	if ( $node->nextSibling ) {
	$node = $node->nextSibling;
	/* Loop back and visit its leftmost (grand)child first. */
	break;
	}
	/* Visit parent only after we've run out of right siblings. */
	$node = $node->parentNode;
	}
	}
	}
	}