WP_Query_Posts_Iterator - External Iterator for posts of WP_Query

WP_Query_Posts_Iterator.php

<?php
/**
 * Class WP_Query_Posts_Iterator
 *
 * External Iterator for posts of WP_Query.
 */
class WP_Query_Posts_Iterator implements iterator {
    /**
     * @var WP_Query
     */
    private $query;
    /**
     * @var int|NULL
     */
    private $index;
    /**
     * @var WP_Post|NULL
     */
    private $post;

    function __construct(WP_Query $query) {
        $this->query = $query;
    }

    /**
     * @return WP_Query
     */
    public function getQuery() {
        return $this->query;
    }

    public function rewind() {
        $this->index = 0;
        $this->setCurrentPost();
    }

    public function valid() {
        $count = (int) $this->query->post_count;
        return $count > 0 and $this->index < $count;
    }

    /**
     * @return WP_Post
     */
    public function current() {
        return $this->post;
    }

    public function key() {
        return $this->index;
    }

    public function next() {
        if ($this->valid() and ++$this->index) {
            $this->setCurrentPost();
        }
    }

    private function setCurrentPost() {
        $has        = $this->index < (int) $this->query->post_count;
        $this->post = $has ? $this->query->posts[$this->index] : NULL;
    }
}