lib/htmlpurifier/HTMLPurifier/AttrDef.php

   1 <?php
   2
   3 /**
   4  * Base class for all validating attribute definitions.
   5  *
   6  * This family of classes forms the core for not only HTML attribute validation,
   7  * but also any sort of string that needs to be validated or cleaned (which
   8  * means CSS properties and composite definitions are defined here too).
   9  * Besides defining (through code) what precisely makes the string valid,
  10  * subclasses are also responsible for cleaning the code if possible.
  11  */
  12
  13 class HTMLPurifier_AttrDef
  14 {
  15
  16     /**
  17      * Tells us whether or not an HTML attribute is minimized. Has no
  18      * meaning in other contexts.
  19      */
  20     var $minimized = false;
  21
  22     /**
  23      * Tells us whether or not an HTML attribute is required. Has no
  24      * meaning in other contexts
  25      */
  26     var $required = false;
  27
  28     /**
  29      * Validates and cleans passed string according to a definition.
  30      *
  31      * @public
  32      * @param $string String to be validated and cleaned.
  33      * @param $config Mandatory HTMLPurifier_Config object.
  34      * @param $context Mandatory HTMLPurifier_AttrContext object.
  35      */
  36     function validate($string, $config, &$context) {
  37         trigger_error('Cannot call abstract function', E_USER_ERROR);
  38     }
  39
  40     /**
  41      * Convenience method that parses a string as if it were CDATA.
  42      *
  43      * This method process a string in the manner specified at
  44      * <http://www.w3.org/TR/html4/types.html#h-6.2> by removing
  45      * leading and trailing whitespace, ignoring line feeds, and replacing
  46      * carriage returns and tabs with spaces.  While most useful for HTML
  47      * attributes specified as CDATA, it can also be applied to most CSS
  48      * values.
  49      *
  50      * @note This method is not entirely standards compliant, as trim() removes
  51      *       more types of whitespace than specified in the spec. In practice,
  52      *       this is rarely a problem, as those extra characters usually have
  53      *       already been removed by HTMLPurifier_Encoder.
  54      *
  55      * @warning This processing is inconsistent with XML's whitespace handling
  56      *          as specified by section 3.3.3 and referenced XHTML 1.0 section
  57      *          4.7.  Compliant processing requires all line breaks normalized
  58      *          to "\n", so the fix is not as simple as fixing it in this
  59      *          function.  Trim and whitespace collapsing are supposed to only
  60      *          occur in NMTOKENs.  However, note that we are NOT necessarily
  61      *          parsing XML, thus, this behavior may still be correct.
  62      *
  63      * @public
  64      */
  65     function parseCDATA($string) {
  66         $string = trim($string);
  67         $string = str_replace("\n", '', $string);
  68         $string = str_replace(array("\r", "\t"), ' ', $string);
  69         return $string;
  70     }
  71
  72     /**
  73      * Factory method for creating this class from a string.
  74      * @param $string String construction info
  75      * @return Created AttrDef object corresponding to $string
  76      * @public
  77      */
  78     function make($string) {
  79         // default implementation, return flyweight of this object
  80         // if overloaded, it is *necessary* for you to clone the
  81         // object (usually by instantiating a new copy) and return that
  82         return $this;
  83     }
  84
  85 }
  86