mediawiki-extensions-Discus.../includes/ImmutableRange.php
Ed Sanders ff46f37b56 ImmutableRange: Port over changes from upstream
* Explode boundary point tuples passed to computePosition
* Note that we won't use previousSibling instead of array_reverse
* Simplify logic using xor

Change-Id: I927256e31b5e441aade91b4fd0d83d8f0d89afbe
2021-10-21 12:42:27 +01:00

492 lines
14 KiB
PHP

<?php
namespace MediaWiki\Extension\DiscussionTools;
use Error;
use Exception;
use Wikimedia\Parsoid\DOM\Comment;
use Wikimedia\Parsoid\DOM\DocumentFragment;
use Wikimedia\Parsoid\DOM\DocumentType;
use Wikimedia\Parsoid\DOM\Node;
use Wikimedia\Parsoid\DOM\ProcessingInstruction;
use Wikimedia\Parsoid\DOM\Text;
/**
* ImmutableRange has a similar API to the DOM Range class.
*
* start/endContainer and offsets can be accessed, as can commonAncestorContainer
* which is lazy evaluated.
*
* setStart and setEnd are still available but return a cloned range.
*/
class ImmutableRange {
private $mCollapsed;
private $mCommonAncestorContainer;
private $mEndContainer;
private $mEndOffset;
private $mStartContainer;
private $mStartOffset;
/**
* Find the common ancestor container of two nodes
*
* @param Node $a
* @param Node $b
* @return Node Common ancestor container
*/
private static function findCommonAncestorContainer( Node $a, Node $b ): Node {
$ancestorsA = [];
$ancestorsB = [];
do {
$ancestorsA[] = $a;
} while ( ( $a = $a->parentNode ) );
do {
$ancestorsB[] = $b;
} while ( ( $b = $b->parentNode ) );
$node = null;
while ( end( $ancestorsA ) && end( $ancestorsA ) === end( $ancestorsB ) ) {
$node = end( $ancestorsA );
array_pop( $ancestorsA );
array_pop( $ancestorsB );
}
if ( !$node ) {
throw new Error( 'Nodes are not in the same document' );
}
return $node;
}
/**
* Get the root ancestor of a node
*
* @param Node $node
* @return Node
*/
private static function getRootNode( Node $node ): Node {
while ( $node->parentNode ) {
$node = $node->parentNode;
'@phan-var Node $node';
}
return $node;
}
/**
* @param Node $startNode
* @param int $startOffset
* @param Node $endNode
* @param int $endOffset
*/
public function __construct(
Node $startNode, int $startOffset, Node $endNode, int $endOffset
) {
$this->mStartContainer = $startNode;
$this->mStartOffset = $startOffset;
$this->mEndContainer = $endNode;
$this->mEndOffset = $endOffset;
}
/**
* @param string $field Field name
* @return mixed
*/
public function __get( string $field ) {
switch ( $field ) {
case 'collapsed':
return $this->mStartContainer === $this->mEndContainer &&
$this->mStartOffset === $this->mEndOffset;
case 'commonAncestorContainer':
if ( !$this->mCommonAncestorContainer ) {
$this->mCommonAncestorContainer =
self::findCommonAncestorContainer( $this->mStartContainer, $this->mEndContainer );
}
return $this->mCommonAncestorContainer;
case 'endContainer':
return $this->mEndContainer;
case 'endOffset':
return $this->mEndOffset;
case 'startContainer':
return $this->mStartContainer;
case 'startOffset':
return $this->mStartOffset;
default:
throw new Exception( 'Invalid property: ' . $field );
}
}
/**
* Clone range with a new start position
*
* @param Node $startNode
* @param int $startOffset
* @return self
*/
public function setStart( Node $startNode, int $startOffset ): self {
return new self(
$startNode, $startOffset, $this->mEndContainer, $this->mEndOffset
);
}
/**
* Clone range with a new end position
*
* @param Node $endNode
* @param int $endOffset
* @return self
*/
public function setEnd( Node $endNode, int $endOffset ): self {
return new self(
$this->mStartContainer, $this->mStartOffset, $endNode, $endOffset
);
}
/**
* Returns true if only a portion of the Node is contained within the Range.
*
* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
* @see https://dom.spec.whatwg.org/#partially-contained
*
* @param Node $node The Node to check against.
* @return bool
*/
private function isPartiallyContainedNode( Node $node ): bool {
return CommentUtils::contains( $node, $this->mStartContainer ) xor
CommentUtils::contains( $node, $this->mEndContainer );
}
/**
* Returns true if the entire Node is within the Range, otherwise false.
*
* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
* @see https://dom.spec.whatwg.org/#contained
*
* @param Node $node The Node to check against.
* @return bool
*/
private function isFullyContainedNode( Node $node ): bool {
return self::getRootNode( $node ) === self::getRootNode( $this->mStartContainer )
&& $this->computePosition( $node, 0, $this->mStartContainer, $this->mStartOffset ) === 'after'
&& $this->computePosition(
// @phan-suppress-next-line PhanUndeclaredProperty
$node, $node->length ?? $node->childNodes->length,
$this->mEndContainer, $this->mEndOffset
) === 'before';
}
/**
* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
* @see https://dom.spec.whatwg.org/#dom-range-clonecontents
*
* @return DocumentFragment
*/
public function cloneContents(): DocumentFragment {
$ownerDocument = $this->mStartContainer->ownerDocument;
$fragment = $ownerDocument->createDocumentFragment();
if ( $this->mStartContainer === $this->mEndContainer
&& $this->mStartOffset === $this->mEndOffset
) {
return $fragment;
}
$originalStartContainer = $this->mStartContainer;
$originalStartOffset = $this->mStartOffset;
$originalEndContainer = $this->mEndContainer;
$originalEndOffset = $this->mEndOffset;
if ( $originalStartContainer === $originalEndContainer
&& ( $originalStartContainer instanceof Text
|| $originalStartContainer instanceof ProcessingInstruction
|| $originalStartContainer instanceof Comment )
) {
$clone = $originalStartContainer->cloneNode();
$clone->nodeValue = $originalStartContainer->substringData(
$originalStartOffset,
$originalEndOffset - $originalStartOffset
);
$fragment->appendChild( $clone );
return $fragment;
}
$commonAncestor = self::findCommonAncestorContainer(
$originalStartContainer,
$originalEndContainer
);
$firstPartiallyContainedChild = null;
if ( !CommentUtils::contains( $originalStartContainer, $originalEndContainer ) ) {
foreach ( $commonAncestor->childNodes as $node ) {
if ( $this->isPartiallyContainedNode( $node ) ) {
$firstPartiallyContainedChild = $node;
break;
}
}
}
$lastPartiallyContainedChild = null;
// Upstream uses lastChild then iterates over previousSibling, however this
// is much slower that copying all the nodes to an array, at least when using
// a native DOMNode, presumably because previousSibling is lazy-evaluated.
if ( !CommentUtils::contains( $originalEndContainer, $originalStartContainer ) ) {
$childNodes = iterator_to_array( $commonAncestor->childNodes );
foreach ( array_reverse( $childNodes ) as $node ) {
if ( $this->isPartiallyContainedNode( $node ) ) {
$lastPartiallyContainedChild = $node;
break;
}
}
}
$containedChildrenStart = null;
$containedChildrenEnd = null;
$child = $firstPartiallyContainedChild ?: $commonAncestor->firstChild;
for ( ; $child; $child = $child->nextSibling ) {
if ( $this->isFullyContainedNode( $child ) ) {
$containedChildrenStart = $child;
break;
}
}
$child = $lastPartiallyContainedChild ?: $commonAncestor->lastChild;
for ( ; $child !== $containedChildrenStart; $child = $child->previousSibling ) {
if ( $this->isFullyContainedNode( $child ) ) {
$containedChildrenEnd = $child;
break;
}
}
if ( !$containedChildrenEnd ) {
$containedChildrenEnd = $containedChildrenStart;
}
// $containedChildrenStart and $containedChildrenEnd may be null here, but this loop still works correctly
for ( $child = $containedChildrenStart; $child !== $containedChildrenEnd; $child = $child->nextSibling ) {
if ( $child instanceof DocumentType ) {
throw new Error();
}
}
if ( $firstPartiallyContainedChild instanceof Text
|| $firstPartiallyContainedChild instanceof ProcessingInstruction
|| $firstPartiallyContainedChild instanceof Comment
) {
$clone = $originalStartContainer->cloneNode();
// @phan-suppress-next-line PhanUndeclaredMethod
$clone->nodeValue = $originalStartContainer->substringData(
$originalStartOffset,
// @phan-suppress-next-line PhanUndeclaredProperty
$originalStartContainer->length - $originalStartOffset
);
$fragment->appendChild( $clone );
} elseif ( $firstPartiallyContainedChild ) {
$clone = $firstPartiallyContainedChild->cloneNode();
$fragment->appendChild( $clone );
$subrange = new self(
$originalStartContainer, $originalStartOffset,
$firstPartiallyContainedChild,
// @phan-suppress-next-line PhanUndeclaredProperty
$firstPartiallyContainedChild->length ?? $firstPartiallyContainedChild->childNodes->length
);
$subfragment = $subrange->cloneContents();
if ( $subfragment->hasChildNodes() ) {
$clone->appendChild( $subfragment );
}
}
// $containedChildrenStart and $containedChildrenEnd may be null here, but this loop still works correctly
for ( $child = $containedChildrenStart; $child !== $containedChildrenEnd; $child = $child->nextSibling ) {
$clone = $child->cloneNode( true );
$fragment->appendChild( $clone );
}
// If not null, this node wasn't processed by the loop
if ( $containedChildrenEnd ) {
$clone = $containedChildrenEnd->cloneNode( true );
$fragment->appendChild( $clone );
}
if ( $lastPartiallyContainedChild instanceof Text
|| $lastPartiallyContainedChild instanceof ProcessingInstruction
|| $lastPartiallyContainedChild instanceof Comment
) {
$clone = $originalEndContainer->cloneNode();
// @phan-suppress-next-line PhanUndeclaredMethod
$clone->nodeValue = $originalEndContainer->substringData(
0,
$originalEndOffset
);
$fragment->appendChild( $clone );
} elseif ( $lastPartiallyContainedChild ) {
$clone = $lastPartiallyContainedChild->cloneNode();
$fragment->appendChild( $clone );
$subrange = new self(
$lastPartiallyContainedChild, 0,
$originalEndContainer, $originalEndOffset
);
$subfragment = $subrange->cloneContents();
if ( $subfragment->hasChildNodes() ) {
$clone->appendChild( $subfragment );
}
}
return $fragment;
}
/**
* Inserts a new Node into at the start of the Range.
*
* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
*
* @see https://dom.spec.whatwg.org/#dom-range-insertnode
*
* @param Node $node The Node to be inserted.
* @return void
*/
public function insertNode( Node $node ): void {
if ( ( $this->mStartContainer instanceof ProcessingInstruction
|| $this->mStartContainer instanceof Comment )
|| ( $this->mStartContainer instanceof Text
&& $this->mStartContainer->parentNode === null )
) {
throw new Error();
}
$referenceNode = null;
if ( $this->mStartContainer instanceof Text ) {
$referenceNode = $this->mStartContainer;
} else {
$referenceNode = $this
->mStartContainer
->childNodes
->item( $this->mStartOffset );
}
$parent = !$referenceNode
? $this->mStartContainer
: $referenceNode->parentNode;
// TODO: Restore this validation check?
// $parent->ensurePreinsertionValidity( $node, $referenceNode );
if ( $this->mStartContainer instanceof Text ) {
$referenceNode = $this->mStartContainer->splitText( $this->mStartOffset );
}
if ( $node === $referenceNode ) {
$referenceNode = $referenceNode->nextSibling;
}
if ( $node->parentNode ) {
$node->parentNode->removeChild( $node );
}
// TODO: Restore this validation check?
// $parent->preinsertNode( $node, $referenceNode );
// $referenceNode may be null, this is okay
$parent->insertBefore( $node, $referenceNode );
}
/**
* Compares the position of two boundary points.
*
* Ported from https://github.com/TRowbotham/PHPDOM (MIT)
* @internal
*
* @see https://dom.spec.whatwg.org/#concept-range-bp-position
*
* @param Node $nodeA
* @param int $offsetA
* @param Node $nodeB
* @param int $offsetB
* @return string 'before'|'after'|'equal'
*/
private function computePosition(
Node $nodeA, int $offsetA, Node $nodeB, int $offsetB
): string {
// 1. Assert: nodeA and nodeB have the same root.
// Removed, not necessary for our usage
// 2. If nodeA is nodeB, then return equal if offsetA is offsetB, before if offsetA is less than offsetB, and
// after if offsetA is greater than offsetB.
if ( $nodeA === $nodeB ) {
if ( $offsetA === $offsetB ) {
return 'equal';
} elseif ( $offsetA < $offsetB ) {
return 'before';
} else {
return 'after';
}
}
$commonAncestor = $this->findCommonAncestorContainer( $nodeB, $nodeA );
if ( $commonAncestor === $nodeA ) {
$AFollowsB = false;
} elseif ( $commonAncestor === $nodeB ) {
$AFollowsB = true;
} else {
// A was not found inside B. Traverse both A & B up to the nodes
// before their common ancestor, then see if A is in the nextSibling
// chain of B.
$b = $nodeB;
while ( $b->parentNode !== $commonAncestor ) {
$b = $b->parentNode;
}
$a = $nodeA;
while ( $a->parentNode !== $commonAncestor ) {
$a = $a->parentNode;
}
$AFollowsB = false;
while ( $b ) {
if ( $a === $b ) {
$AFollowsB = true;
break;
}
$b = $b->nextSibling;
}
}
if ( $AFollowsB ) {
// Swap variables
[ $nodeB, $nodeA ] = [ $nodeA, $nodeB ];
[ $offsetB, $offsetA ] = [ $offsetA, $offsetB ];
}
$ancestor = $nodeB->parentNode;
while ( $ancestor ) {
if ( $ancestor === $nodeA ) {
break;
}
$ancestor = $ancestor->parentNode;
}
if ( $ancestor ) {
$child = $nodeB;
while ( $child ) {
if ( $child->parentNode === $nodeA ) {
break;
}
$child = $child->parentNode;
}
// Phan complains that $child may be null here, but that can't happen, because at this point
// we know that $nodeA is an ancestor of $nodeB, so the loop above will stop before the root.
// @phan-suppress-next-line PhanTypeMismatchArgumentNullable
if ( CommentUtils::childIndexOf( $child ) < $offsetA ) {
return $AFollowsB ? 'before' : 'after';
}
}
return $AFollowsB ? 'after' : 'before';
}
}