protected function fosterParent(Tag $tag)
{
if (!empty($this->openTags)) {
$tagName = $tag->getName();
$tagConfig = $this->tagsConfig[$tagName];
if (!empty($tagConfig['rules']['fosterParent'])) {
$parent = \end($this->openTags);
$parentName = $parent->getName();
if (isset($tagConfig['rules']['fosterParent'][$parentName])) {
if ($parentName !== $tagName && $this->currentFixingCost < $this->maxFixingCost) {
$child = $this->addCopyTag($parent, $tag->getPos() + $tag->getLen(), 0);
$tag->cascadeInvalidationTo($child);
$child->setSortPriority($tag->getSortPriority() + 1);
}
$this->tagStack[] = $tag;
$this->addMagicEndTag($parent, $tag->getPos())->setSortPriority($tag->getSortPriority() - 1);
$this->currentFixingCost += \count($this->tagStack);
return \true;
}
}
}
return \false;
}
/**
* @testdox Mutual invalidation doesn't cause an infinite loop
*/
public function testInvalidateNoInfiniteLoop()
{
$tag1 = new Tag(Tag::START_TAG, 'X', 0, 0);
$tag2 = new Tag(Tag::START_TAG, 'X', 0, 0);
$tag1->cascadeInvalidationTo($tag2);
$tag2->cascadeInvalidationTo($tag1);
$tag1->invalidate();
}
/**
* Apply fosterParent rules associated with given tag
*
* NOTE: this rule has the potential for creating an unbounded loop, either if a tag tries to
* foster itself or two or more tags try to foster each other in a loop. We mitigate the
* risk by preventing a tag from creating a child of itself (the parent still gets closed)
* and by checking and increasing the currentFixingCost so that a loop of multiple tags
* do not run indefinitely. The default tagLimit and nestingLimit also serve to prevent the
* loop from running indefinitely
*
* @param Tag $tag Tag
* @return bool Whether a new tag has been added
*/
protected function fosterParent(Tag $tag)
{
if (!empty($this->openTags)) {
$tagName = $tag->getName();
$tagConfig = $this->tagsConfig[$tagName];
if (!empty($tagConfig['rules']['fosterParent'])) {
$parent = end($this->openTags);
$parentName = $parent->getName();
if (isset($tagConfig['rules']['fosterParent'][$parentName])) {
if ($parentName !== $tagName && $this->currentFixingCost < $this->maxFixingCost) {
// Add a 0-width copy of the parent tag right after this tag, and make it
// depend on this tag
$child = $this->addCopyTag($parent, $tag->getPos() + $tag->getLen(), 0);
$tag->cascadeInvalidationTo($child);
}
++$this->currentFixingCost;
// Reinsert current tag
$this->tagStack[] = $tag;
// And finally close its parent
$this->addMagicEndTag($parent, $tag->getPos());
return true;
}
}
}
return false;
}
