mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/DiscussionTools
synced 2024-11-11 17:02:28 +00:00
142 lines
3.1 KiB
PHP
142 lines
3.1 KiB
PHP
<?php
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namespace MediaWiki\Extension\DiscussionTools;
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use DOMException;
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use Throwable;
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use Wikimedia\Parsoid\DOM\Node;
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/**
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* Partial implementation of W3 DOM4 TreeWalker interface.
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*
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* See also:
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* - https://dom.spec.whatwg.org/#interface-treewalker
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*
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* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
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*/
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class TreeWalker {
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public Node $root;
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public int $whatToShow;
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public Node $currentNode;
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/** @var callable|null */
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public $filter;
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private bool $isActive = false;
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/**
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* See https://dom.spec.whatwg.org/#interface-treewalker
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*/
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public function __construct(
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Node $root,
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int $whatToShow = NodeFilter::SHOW_ALL,
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?callable $filter = null
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) {
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$this->currentNode = $root;
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$this->filter = $filter;
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$this->root = $root;
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$this->whatToShow = $whatToShow;
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}
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/**
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* See https://dom.spec.whatwg.org/#dom-treewalker-nextnode
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*
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* @return Node|null The current node
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*/
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public function nextNode(): ?Node {
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$node = $this->currentNode;
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$result = NodeFilter::FILTER_ACCEPT;
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while ( true ) {
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while ( $result !== NodeFilter::FILTER_REJECT && $node->firstChild !== null ) {
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$node = $node->firstChild;
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$result = $this->filterNode( $node );
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if ( $result === NodeFilter::FILTER_ACCEPT ) {
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$this->currentNode = $node;
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return $node;
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}
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}
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$sibling = null;
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$temp = $node;
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while ( $temp !== null ) {
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if ( $temp === $this->root ) {
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return null;
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}
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$sibling = $temp->nextSibling;
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if ( $sibling !== null ) {
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$node = $sibling;
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break;
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}
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$temp = $temp->parentNode;
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}
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'@phan-var Node $node';
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$result = $this->filterNode( $node );
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if ( $result === NodeFilter::FILTER_ACCEPT ) {
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$this->currentNode = $node;
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return $node;
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}
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}
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}
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/**
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* Filters a node.
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*
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* @internal
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*
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* @see https://dom.spec.whatwg.org/#concept-node-filter
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*
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* @param Node $node The node to check.
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* @return int Returns one of NodeFilter's FILTER_* constants.
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* - NodeFilter::FILTER_ACCEPT
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* - NodeFilter::FILTER_REJECT
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* - NodeFilter::FILTER_SKIP
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*/
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private function filterNode( Node $node ): int {
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if ( $this->isActive ) {
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throw new DOMException( 'InvalidStateError' );
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}
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// Let n be node’s nodeType attribute value minus 1.
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$n = $node->nodeType - 1;
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// If the nth bit (where 0 is the least significant bit) of whatToShow
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// is not set, return FILTER_SKIP.
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if ( !( ( 1 << $n ) & $this->whatToShow ) ) {
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return NodeFilter::FILTER_SKIP;
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}
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// If filter is null, return FILTER_ACCEPT.
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if ( !$this->filter ) {
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return NodeFilter::FILTER_ACCEPT;
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}
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$this->isActive = true;
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try {
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// Let $result be the return value of call a user object's operation
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// with traverser's filter, "acceptNode", and Node. If this throws
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// an exception, then unset traverser's active flag and rethrow the
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// exception.
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$result = $this->filter instanceof NodeFilter
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? $this->filter->acceptNode( $node )
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: ( $this->filter )( $node );
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} catch ( Throwable $e ) {
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$this->isActive = false;
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throw $e;
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}
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$this->isActive = false;
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return $result;
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}
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}
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