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<?php |
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namespace enshrined\svgSanitize\ElementReference; |
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|
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use enshrined\svgSanitize\data\XPath; |
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use enshrined\svgSanitize\Exceptions\NestingException; |
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use enshrined\svgSanitize\Helper; |
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|
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class Resolver |
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{ |
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/** |
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* @var XPath |
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*/ |
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protected $xPath; |
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|
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/** |
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* @var Subject[] |
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*/ |
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protected $subjects = []; |
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|
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/** |
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* @var array DOMElement[] |
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*/ |
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protected $elementsToRemove = []; |
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|
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/** |
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* @var int |
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*/ |
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protected $useNestingLimit; |
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|
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public function __construct(XPath $xPath, $useNestingLimit) |
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{ |
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$this->xPath = $xPath; |
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$this->useNestingLimit = $useNestingLimit; |
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} |
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|
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public function collect() |
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{ |
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$this->collectIdentifiedElements(); |
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$this->processReferences(); |
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$this->determineInvalidSubjects(); |
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} |
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|
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/** |
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* Resolves one subject by element. |
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* |
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* @param \DOMElement $element |
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* @param bool $considerChildren Whether to search in Subject's children as well |
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* @return Subject|null |
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*/ |
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public function findByElement(\DOMElement $element, $considerChildren = false) |
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{ |
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foreach ($this->subjects as $subject) { |
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if ( |
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$element === $subject->getElement() |
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|| $considerChildren && Helper::isElementContainedIn($element, $subject->getElement()) |
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) { |
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return $subject; |
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} |
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} |
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return null; |
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} |
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|
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/** |
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* Resolves subjects (plural!) by element id - in theory malformed |
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* DOM might have same ids assigned to different elements and leaving |
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* it to client/browser implementation which element to actually use. |
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* |
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* @param string $elementId |
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* @return Subject[] |
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*/ |
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public function findByElementId($elementId) |
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{ |
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return array_filter( |
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$this->subjects, |
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function (Subject $subject) use ($elementId) { |
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return $elementId === $subject->getElementId(); |
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} |
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); |
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} |
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|
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/** |
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* Collects elements having `id` attribute (those that can be referenced). |
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*/ |
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protected function collectIdentifiedElements() |
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{ |
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/** @var \DOMNodeList|\DOMElement[] $elements */ |
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$elements = $this->xPath->query('//*[@id]'); |
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foreach ($elements as $element) { |
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$this->subjects[$element->getAttribute('id')] = new Subject($element, $this->useNestingLimit); |
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} |
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} |
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|
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/** |
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* Processes references from and to elements having `id` attribute concerning |
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* their occurrence in `<use ... xlink:href="#identifier">` statements. |
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*/ |
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protected function processReferences() |
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{ |
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// Note: the href attribute is deliberately not filtered in the XPath predicate. |
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// XPath attribute matching is case sensitive, so `[@href or @xlink:href]` would |
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// skip `<use HrEf="#id">`/`<use xlink:HrEf="#id">` - names that |
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// `Sanitizer::cleanHrefAttributes()` normalizes back to `href`/`xlink:href` |
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// afterwards, which would hand back a live reference the graph never saw. |
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$useNodeName = $this->xPath->createNodeName('use'); |
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foreach ($this->subjects as $subject) { |
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$useElements = $this->xPath->query( |
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$useNodeName, |
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$subject->getElement() |
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); |
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|
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/** @var \DOMElement $useElement */ |
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foreach ($useElements as $useElement) { |
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$useId = Helper::extractIdReferenceFromHref( |
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Helper::getElementHref($useElement) |
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); |
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if ($useId === null || !isset($this->subjects[$useId])) { |
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continue; |
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} |
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$subject->addUse($this->subjects[$useId]); |
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$this->subjects[$useId]->addUsedIn($subject); |
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} |
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} |
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} |
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|
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/** |
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* Determines and tags infinite loops. |
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*/ |
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protected function determineInvalidSubjects() |
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{ |
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foreach ($this->subjects as $subject) { |
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|
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if (in_array($subject->getElement(), $this->elementsToRemove)) { |
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continue; |
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} |
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|
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$useId = Helper::extractIdReferenceFromHref( |
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Helper::getElementHref($subject->getElement()) |
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); |
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|
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try { |
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if ($useId === $subject->getElementId()) { |
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$this->markSubjectAsInvalid($subject); |
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} elseif ($subject->hasInfiniteLoop()) { |
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$this->markSubjectAsInvalid($subject); |
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} |
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} catch (NestingException $e) { |
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$this->elementsToRemove[] = $e->getElement(); |
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$this->markSubjectAsInvalid($subject); |
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} |
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} |
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} |
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|
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/** |
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* Get all the elements that caused a nesting exception. |
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* |
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* @return array |
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*/ |
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public function getElementsToRemove() { |
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return $this->elementsToRemove; |
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} |
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|
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/** |
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* The Subject is invalid for some reason, therefore we should |
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* remove it and all it's child usages. |
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* |
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* @param Subject $subject |
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*/ |
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protected function markSubjectAsInvalid(Subject $subject) { |
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$this->elementsToRemove = array_merge( |
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$this->elementsToRemove, |
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$subject->clearInternalAndGetAffectedElements() |
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); |
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} |
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} |
