HTML-DOM/lib/NodeList.php

<?php
/**
 * @license MIT
 * Copyright 2017 Dustin Wilson, J. King, et al.
 * See LICENSE and AUTHORS files for details
 */

declare(strict_types=1);
namespace MensBeam\HTML\DOM;
use MensBeam\Framework\MagicProperties;


# A NodeList object is a collection of nodes.
#
# A collection is an object that represents a list of nodes. A collection can be
# either live or static. Unless otherwise stated, a collection must be live.
#
# If a collection is live, then the attributes and methods on that object must
# operate on the actual underlying data, not a snapshot of the data.
#
# When a collection is created, a filter and a root are associated with it.
#
# The collection then represents a view of the subtree rooted at the
# collection’s root, containing only nodes that match the given filter. The view
# is linear. In the absence of specific requirements to the contrary, the nodes
# within the collection must be sorted in tree order.
class NodeList implements \ArrayAccess, \Countable, \Iterator {
    use MagicProperties;

    protected ?\Closure $filter = null;
    protected int $_length = 0;
    protected ?array $nodeArray = null;
    protected int $position = 0;


    protected function __get_length(): int {
        # The length attribute must return the number of nodes represented by the
        # collection.
        return $this->count();
    }


    protected function __construct(array|\Closure $arrayOrClosure = []) {
        // In this implementation the root part of the creation is handled either before
        // the NodeList is created (array) or within the filter (\Closure).
        if ($arrayOrClosure === null) {
            $arrayOrClosure = [];
        }

        if (is_callable($arrayOrClosure)) {
            $this->filter = $arrayOrClosure;
        } else {
            // Check types while also unpacking the iterable.
            $array = [];
            foreach ($arrayOrClosure as $i) {
                if (!$i instanceof Node) {
                    $type = gettype($i);
                    if ($type === 'object') {
                        $type = get_class($i);
                    }
                    throw new Exception(Exception::ARGUMENT_TYPE_ERROR, 1, 'arrayOrClosure', 'array<Node>|\\Closure<array<Node>>', $type);
                }

                $array[] = $i;
            }

            $this->nodeArray = $array;
            $this->_length = count($array);
        }
    }

    public function count(): int {
        if ($this->nodeArray !== null) {
            return $this->_length;
        }

        $nodeArray = ($this->filter)();
        return count($nodeArray);
    }

    public function current(): ?Node {
        return $this->item($this->position);
    }

    public function item(int $index): ?Node {
        # The item(index) method must return the indexth node in the collection. If
        # there is no indexth node in the collection, then the method must return null.
        if ($index >= $this->count()) {
            return null;
        }

        $nodeArray = ($this->nodeArray !== null) ? $this->nodeArray : ($this->filter)();
        if (array_key_exists($index, $nodeArray)) {
            return $nodeArray[$index];
        }

        return null;
    }

    public function key(): int {
        return $this->position;
    }

    public function next(): void {
        $this->position++;
    }

    public function rewind(): void {
        $this->position = 0;
    }

    public function offsetExists($offset): bool {
        $nodeArray = ($this->nodeArray !== null) ? $this->nodeArray : ($this->filter)();
        return array_key_exists($offset, $nodeArray);
    }

    public function offsetGet($offset): ?Node {
        return $this->item($offset);
    }

    public function offsetSet($offset, $value): void {
        // NodeLists are immutable; the spec is ambiguous as to what to do here.
        // Browsers silently fail here, so that's what we're going to do.
    }

    public function offsetUnset($offset): void {
        // NodeLists are immutable; the spec is ambiguous as to what to do here.
        // Browsers silently fail here, so that's what we're going to do.
    }

    public function valid() {
        $this->offsetExists($this->position);
    }
}