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htmlpurifier/library/HTMLPurifier/ChildDef/Optional.php
Edward Z. Yang 0767bbc12d Rewrite FixNesting implementation to be tree-based.
This mega-patch rips out the FixNesting implementation and the related
ChildDef components.  The primary algorithmic change is to convert from
use of tokens to tree nodes, which are far more amenable to the style
of processing that FixNesting uses.  Additionally, FixNesting has been
changed to go bottom-up rather than top-down, in order to avoid needing
to implement backtracking.

This patch simplifies a good deal of the relevant logic, since we no
longer need to continually recalculate the nesting structure when
processing things.  However, the conversion to the alternate format
incurs some overhead, so for small inputs these changes are not a win.
One possibility to greatly reduce the constant factors here is to switch
to entirely using libxml's representation, and never serializing tokens;
this would require one to rewrite injectors, however.

The iterative post-order traversal in FixNesting is a bit subtle, but
we have essentially reified the stack and continuations.

We've removed support for %Core.EscapeInvalidChildren.

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
2013-10-20 22:37:01 -07:00

46 lines
1.2 KiB
PHP

<?php
/**
* Definition that allows a set of elements, and allows no children.
* @note This is a hack to reuse code from HTMLPurifier_ChildDef_Required,
* really, one shouldn't inherit from the other. Only altered behavior
* is to overload a returned false with an array. Thus, it will never
* return false.
*/
class HTMLPurifier_ChildDef_Optional extends HTMLPurifier_ChildDef_Required
{
/**
* @type bool
*/
public $allow_empty = true;
/**
* @type string
*/
public $type = 'optional';
/**
* @param array $children
* @param HTMLPurifier_Config $config
* @param HTMLPurifier_Context $context
* @return array
*/
public function validateChildren($children, $config, $context)
{
$result = parent::validateChildren($children, $config, $context);
// we assume that $children is not modified
if ($result === false) {
if (empty($children)) {
return true;
} elseif ($this->whitespace) {
return $children;
} else {
return array();
}
}
return $result;
}
}
// vim: et sw=4 sts=4