Base TreeWalker implementation on PHPDOM

For consistency with other DOM implementations.

Change-Id: I20447d880ccd3b70b6694b36ea2f63dd0c42fa84
This commit is contained in:
Ed Sanders 2020-11-16 00:13:55 +00:00
parent 5a5b2e61f1
commit 763ce88021

View file

@ -4,6 +4,7 @@ namespace MediaWiki\Extension\DiscussionTools;
use DOMNode;
use Exception;
use Throwable;
/**
* Partial implementation of W3 DOM4 TreeWalker interface.
@ -11,7 +12,7 @@ use Exception;
* See also:
* - https://dom.spec.whatwg.org/#interface-treewalker
*
* Adapted from https://github.com/Krinkle/dom-TreeWalker-polyfill/blob/master/src/TreeWalker-polyfill.js
* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
*/
class TreeWalker {
@ -20,83 +21,24 @@ class TreeWalker {
public $currentNode;
public $filter;
/**
* See https://dom.spec.whatwg.org/#concept-node-filter
*
* @param TreeWalker $tw
* @param DOMNode $node
* @return int Constant NodeFilter::FILTER_ACCEPT,
* NodeFilter::FILTER_REJECT or NodeFilter::FILTER_SKIP.
*/
private function nodeFilter( TreeWalker $tw, DOMNode $node ) {
// Maps nodeType to whatToShow
if ( !( ( ( 1 << ( $node->nodeType - 1 ) ) & $tw->whatToShow ) ) ) {
return NodeFilter::FILTER_SKIP;
}
if ( $tw->filter === null ) {
return NodeFilter::FILTER_ACCEPT;
}
return $tw->filter->acceptNode( $node );
}
/**
* Based on WebKit's NodeTraversal::nextSkippingChildren
* https://trac.webkit.org/browser/trunk/Source/WebCore/dom/NodeTraversal.h?rev=137221#L103
*
* @param DOMNode $node
* @param DOMNode $stayWithin
* @return DOMNode|null
*/
private function nextSkippingChildren( DOMNode $node, DOMNode $stayWithin ) : ?DOMNode {
if ( $node === $stayWithin ) {
return null;
}
if ( $node->nextSibling !== null ) {
return $node->nextSibling;
}
/**
* Based on WebKit's NodeTraversal::nextAncestorSibling
* https://trac.webkit.org/browser/trunk/Source/WebCore/dom/NodeTraversal.cpp?rev=137221#L43
*/
while ( $node->parentNode !== null ) {
$node = $node->parentNode;
if ( $node === $stayWithin ) {
return null;
}
if ( $node->nextSibling !== null ) {
return $node->nextSibling;
}
}
return null;
}
private $isActive = false;
/**
* See https://dom.spec.whatwg.org/#interface-treewalker
*
* @param DOMNode $root
* @param int|null $whatToShow
* @param int $whatToShow
* @param callable|null $filter
* @throws Exception
*/
public function __construct( DOMNode $root, $whatToShow = null, callable $filter = null ) {
if ( !$root->nodeType ) {
throw new Exception( 'DOMException: NOT_SUPPORTED_ERR' );
}
$this->root = $root;
$this->whatToShow = (int)$whatToShow ?: 0;
public function __construct(
DOMNode $root,
int $whatToShow = NodeFilter::SHOW_ALL,
callable $filter = null
) {
$this->currentNode = $root;
if ( !$filter ) {
$this->filter = null;
} else {
$this->filter = new NodeFilter();
$this->filter->filter = $filter;
}
$this->filter = $filter;
$this->root = $root;
$this->whatToShow = $whatToShow;
}
/**
@ -111,23 +53,93 @@ class TreeWalker {
while ( true ) {
while ( $result !== NodeFilter::FILTER_REJECT && $node->firstChild !== null ) {
$node = $node->firstChild;
$result = $this->nodeFilter( $this, $node );
$result = $this->filterNode( $node );
if ( $result === NodeFilter::FILTER_ACCEPT ) {
$this->currentNode = $node;
return $node;
}
}
$following = $this->nextSkippingChildren( $node, $this->root );
if ( $following !== null ) {
$node = $following;
} else {
return null;
$sibling = null;
$temp = $node;
while ( $temp !== null ) {
if ( $temp === $this->root ) {
return null;
}
$sibling = $temp->nextSibling;
if ( $sibling !== null ) {
$node = $sibling;
break;
}
$temp = $temp->parentNode;
}
$result = $this->nodeFilter( $this, $node );
$result = $this->filterNode( $node );
if ( $result === NodeFilter::FILTER_ACCEPT ) {
$this->currentNode = $node;
return $node;
}
}
}
/**
* Filters a node.
*
* @internal
*
* @see https://dom.spec.whatwg.org/#concept-node-filter
*
* @param DOMNode $node The node to check.
* @return int Returns one of NodeFilter's FILTER_* constants.
* - NodeFilter::FILTER_ACCEPT
* - NodeFilter::FILTER_REJECT
* - NodeFilter::FILTER_SKIP
* @throws Exception
*/
private function filterNode( DOMNode $node ): int {
if ( $this->isActive ) {
throw new Exception( 'InvalidStateError' );
}
// Let n be nodes nodeType attribute value minus 1.
$n = $node->nodeType - 1;
// If the nth bit (where 0 is the least significant bit) of whatToShow
// is not set, return FILTER_SKIP.
if ( !( ( 1 << $n ) & $this->whatToShow ) ) {
return NodeFilter::FILTER_SKIP;
}
// If filter is null, return FILTER_ACCEPT.
if ( !$this->filter ) {
return NodeFilter::FILTER_ACCEPT;
}
$this->isActive = true;
try {
// Let $result be the return value of call a user object's operation
// with traverser's filter, "acceptNode", and Node. If this throws
// an exception, then unset traverser's active flag and rethrow the
// exception.
$result = $this->filter instanceof NodeFilter
? $this->filter->acceptNode( $node )
: ( $this->filter )( $node );
} catch ( Throwable $e ) {
$this->isActive = false;
throw $e;
}
$this->isActive = false;
return $result;
}
}