<?php
/**
* Base class for all validating attribute definitions.
*
* This family of classes forms the core for not only HTML attribute validation,
* but also any sort of string that needs to be validated or cleaned (which
* means CSS properties and composite definitions are defined here too).
* Besides defining (through code) what precisely makes the string valid,
* subclasses are also responsible for cleaning the code if possible.
*/
abstract class HTMLPurifier_AttrDef
{
/**
* Tells us whether or not an HTML attribute is minimized.
* Has no meaning in other contexts.
* @type bool
*/
public $minimized = false;
/**
* Tells us whether or not an HTML attribute is required.
* Has no meaning in other contexts
* @type bool
*/
public $required = false;
/**
* Validates and cleans passed string according to a definition.
*
* @param string $string String to be validated and cleaned.
* @param HTMLPurifier_Config $config Mandatory HTMLPurifier_Config object.
* @param HTMLPurifier_Context $context Mandatory HTMLPurifier_Context object.
*/
abstract public function validate($string, $config, $context);
/**
* Convenience method that parses a string as if it were CDATA.
*
* This method process a string in the manner specified at
* <http://www.w3.org/TR/html4/types.html#h-6.2> by removing
* leading and trailing whitespace, ignoring line feeds, and replacing
* carriage returns and tabs with spaces. While most useful for HTML
* attributes specified as CDATA, it can also be applied to most CSS
* values.
*
* @note This method is not entirely standards compliant, as trim() removes
* more types of whitespace than specified in the spec. In practice,
* this is rarely a problem, as those extra characters usually have
* already been removed by HTMLPurifier_Encoder.
*
* @warning This processing is inconsistent with XML's whitespace handling
* as specified by section 3.3.3 and referenced XHTML 1.0 section
* 4.7. However, note that we are NOT necessarily
* parsing XML, thus, this behavior may still be correct. We
* assume that newlines have been normalized.
*/
public function parseCDATA($string)
{
$string = trim($string);
$string = str_replace(array("\n", "\t", "\r"), ' ', $string);
return $string;
}
/**
* Factory method for creating this class from a string.
* @param string $string String construction info
* @return HTMLPurifier_AttrDef Created AttrDef object corresponding to $string
*/
public function make($string)
{
// default implementation, return a flyweight of this object.
// If $string has an effect on the returned object (i.e. you
// need to overload this method), it is best
// to clone or instantiate new copies. (Instantiation is safer.)
return $this;
}
/**
* Removes spaces from rgb(0, 0, 0) so that shorthand CSS properties work
* properly. THIS IS A HACK!
* @param string $string a CSS colour definition
* @return string
*/
protected function mungeRgb($string)
{
$p = '\s*(\d+(\.\d+)?([%]?))\s*';
if (preg_match('/(rgba|hsla)\(/', $string)) {
return preg_replace('/(rgba|hsla)\('.$p.','.$p.','.$p.','.$p.'\)/', '\1(\2,\5,\8,\11)', $string);
}
return preg_replace('/(rgb|hsl)\('.$p.','.$p.','.$p.'\)/', '\1(\2,\5,\8)', $string);
}
/**
* Parses a possibly escaped CSS string and returns the "pure"
* version of it.
*/
protected function expandCSSEscape($string)
{
// flexibly parse it
$ret = '';
for ($i = 0, $c = strlen($string); $i < $c; $i++) {
if ($string[$i] === '\\') {
$i++;
if ($i >= $c) {
$ret .= '\\';
break;
}
if (ctype_xdigit($string[$i])) {
$code = $string[$i];
for ($a = 1, $i++; $i < $c && $a < 6; $i++, $a++) {
if (!ctype_xdigit($string[$i])) {
break;
}
$code .= $string[$i];
}
// We have to be extremely careful when adding
// new characters, to make sure we're not breaking
// the encoding.
$char = HTMLPurifier_Encoder::unichr(hexdec($code));
if (HTMLPurifier_Encoder::cleanUTF8($char) === '') {
continue;
}
$ret .= $char;
if ($i < $c && trim($string[$i]) !== '') {
$i--;
}
continue;
}
if ($string[$i] === "\n") {
continue;
}
}
$ret .= $string[$i];
}
return $ret;
}
}
// vim: et sw=4 sts=4