HTML-DOM/lib/ActiveFormattingElementsList.php
J. King 6b42f08fbc Change some if-the-exception blocks to assertions
This has only been done some parts of the code that are internal
to the parser at large.
2019-12-12 17:35:24 -05:00

204 lines
8.5 KiB
PHP

<?php
declare(strict_types=1);
namespace dW\HTML5;
# 8.2.3.3. The list of active formatting elements
# Initially, the list of active formatting elements is empty. It is used to
# handle mis-nested formatting element tags.
#
# The list contains elements in the formatting category, and markers. The
# markers are inserted when entering applet, object, marquee, template, td, th,
# and caption elements, and are used to prevent formatting from "leaking" into
# applet, object, marquee, template, td, th, and caption elements.
#
# In addition, each element in the list of active formatting elements is
# associated with the token for which it was created, so that further elements
# can be created for that token if necessary.
class ActiveFormattingElementsList extends Stack {
protected $_storage = [];
protected $stack;
public function __construct(OpenElementsStack $stack) {
$this->stack = $stack;
}
public function offsetSet($offset, $value) {
assert($offset >= 0 && $offset <= count($this->_storage), new Exception(Exception::STACK_INVALID_INDEX, $offset));
if (is_null($offset)) {
# When the steps below require the UA to push onto the list of active formatting
# elements an element element, the UA must perform the following steps:
if ($value instanceof \DOMElement) {
# 1. If there are already three elements in the list of active formatting
# elements after the last marker, if any, or anywhere in the list if there are
# no markers, that have the same tag name, namespace, and attributes as element,
# then remove the earliest such element from the list of active formatting
# elements. For these purposes, the attributes must be compared as they were
# when the elements were created by the parser; two elements have the same
# attributes if all their parsed attributes can be paired such that the two
# attributes in each pair have identical names, namespaces, and values (the
# order of the attributes does not matter).
$lastMarkerIndex = $this->lastMarker;
$start = ($lastMarkerIndex !== false) ? $lastMarkerIndex + 1 : 0;
$length = count($this->_storage);
if ($start < $length - 3) {
$count = 0;
for ($i = $length - 1; $i > $start; $i--) {
$cur = $this->_storage[$i];
if ($cur->nodeName === $value->nodeName && $cur->namespaceURI === $value->namespaceURI && $cur->attributes->length === $value->attributes->length) {
$a = [];
for ($j = 0; $j < $cur->attributes->length; $cur++) {
$cur2 = $cur->attributes[$j];
$a[] = $cur2->name . $cur2->namespaceURI . $cur2->value;
}
$b = [];
for ($j = 0; $j < $value->attributes->length; $cur++) {
$cur2 = $value->attributes[$j];
$b[] = $cur2->name . $cur2->namespaceURI . $cur2->value;
}
sort($a);
sort($b);
if ($a === $b) {
$count++;
if ($count === 3) {
$this->offsetUnset($i);
break;
}
}
}
}
}
}
# 2. Add element to the list of active formatting elements.
$this->_storage[] = $value;
} else {
parent::offsetSet($offset, $value);
}
}
public function insert(StartTagToken $token, \DOMElement $element) {
$this->_storage[] = [
'token' => $token,
'element' => $element
];
}
public function insertMarker() {
$this->offsetSet(null, new ActiveFormattingElementMarker());
}
public function reconstruct() {
# When the steps below require the UA to reconstruct the active formatting
# elements, the UA must perform the following steps:
// Yes, I know this uses gotos, but here are the reasons for using them:
// 1. The spec seems to actively encourage using them, even providing
// suggestions on what to name the labels.
// 2. It'd be a pain to program and maintain without them because the algorithm
// jumps around all over the place.
# 1. If there are no entries in the list of active formatting elements, then
# there is nothing to reconstruct; stop this algorithm.
if (count($this->_storage) === 0) {
return;
}
# 2. If the last (most recently added) entry in the list of active formatting
# elements is a marker, or if it is an element that is in the stack of open
# elements, then there is nothing to reconstruct; stop this algorithm.
$entry = end($this->_storage);
if ($entry instanceof ActiveFormattingElementMarker || in_array($entry['element'], $this->stack)) {
return;
}
# 3. Let entry be the last (most recently added) element in the list of active
# formatting elements.
// Done already.
# 4. Rewind: If there are no entries before entry in the list of active
# formatting elements, then jump to the step labeled Create.
rewind:
if (count($this->_storage) === 1) {
goto create;
}
# 5. Let entry be the entry one earlier than entry in the list of active
# formatting elements.
$entry = prev($this->_storage);
# 6. If entry is neither a marker nor an element that is also in the stack of
# open elements, go to the step labeled Rewind.
if (!$entry instanceof ActiveFormattingElementMarker || $this->stack->search($entry['element']) === -1) {
goto rewind;
}
# 7. Advance: Let entry be the element one later than entry in the list of
# active formatting elements.
advance:
$entry = next($this->_storage);
# 8. Create: Insert an HTML element for the token for which the element entry
# was created, to obtain new element.
create:
$element = TreeBuilder::insertStartTagToken($entry['token']);
# 9. Replace the entry for entry in the list with an entry for new element.
$this->_storage[key($this->_storage)]['element'] = $element;
# 10. If the entry for new element in the list of active formatting elements is
# not the last entry in the list, return to the step labeled Advance.
if ($entry !== $this->_storage[count($this->_storage) - 1]) {
goto advance;
}
}
public function clearToTheLastMarker() {
# When the steps below require the UA to clear the list of active formatting
# elements up to the last marker, the UA must perform the following steps:
# 1. Let entry be the last (most recently added) entry in the list of active
# formatting elements.
# 2. Remove entry from the list of active formatting elements.
# 3. If entry was a marker, then stop the algorithm at this point. The list has
# been cleared up to the last marker.
# 4. Go to step 1.
// Just going to go backwards through the array until a marker is reached. Does
// the same thing.
for ($end = count($this->_storage) - 1, $i = $end; $i >= 0; $i--) {
if ($this->_storage[$i] instanceof ActiveFormattingElementMarker) {
return;
}
unset($this->_storage[$i]);
}
// Reindex the array.
$this->_storage = array_values($this->_storage);
}
public function __get($property) {
$value = parent::__get($property);
if (!is_null($value)) {
return $value;
}
switch ($property) {
case 'lastMarker':
for ($end = count($this->_storage) - 1, $i = $end; $i >= 0; $i--) {
if ($this->_storage[$i] instanceof ActiveFormattingElementMarker) {
return $i;
}
}
return false;
break;
default: return null;
}
}
}
class ActiveFormattingElementMarker {}