<?php
/**
* Injects tokens into the document while parsing for well-formedness.
* This enables "formatter-like" functionality such as auto-paragraphing,
* smiley-ification and linkification to take place.
*
* A note on how handlers create changes; this is done by assigning a new
* value to the $token reference. These values can take a variety of forms and
* are best described HTMLPurifier_Strategy_MakeWellFormed->processToken()
* documentation.
*
* @todo Allow injectors to request a re-run on their output. This
* would help if an operation is recursive.
*/
abstract class HTMLPurifier_Injector
{
/**
* Advisory name of injector, this is for friendly error messages
*/
public $name;
/**
* Instance of HTMLPurifier_HTMLDefinition
*/
protected $htmlDefinition;
/**
* Reference to CurrentNesting variable in Context. This is an array
* list of tokens that we are currently "inside"
*/
protected $currentNesting;
/**
* Reference to InputTokens variable in Context. This is an array
* list of the input tokens that are being processed.
*/
protected $inputTokens;
/**
* Reference to InputIndex variable in Context. This is an integer
* array index for $this->inputTokens that indicates what token
* is currently being processed.
*/
protected $inputIndex;
/**
* Array of elements and attributes this injector creates and therefore
* need to be allowed by the definition. Takes form of
* array('element' => array('attr', 'attr2'), 'element2')
*/
public $needed = array();
/**
* Index of inputTokens to rewind to.
*/
protected $rewind = false;
/**
* Rewind to a spot to re-perform processing. This is useful if you
* deleted a node, and now need to see if this change affected any
* earlier nodes. Rewinding does not affect other injectors, and can
* result in infinite loops if not used carefully.
* @warning HTML Purifier will prevent you from fast-forwarding with this
* function.
*/
public function rewind($index) {
$this->rewind = $index;
}
/**
* Retrieves rewind, and then unsets it.
*/
public function getRewind() {
$r = $this->rewind;
$this->rewind = false;
return $r;
}
/**
* Prepares the injector by giving it the config and context objects:
* this allows references to important variables to be made within
* the injector. This function also checks if the HTML environment
* will work with the Injector (see checkNeeded()).
* @param $config Instance of HTMLPurifier_Config
* @param $context Instance of HTMLPurifier_Context
* @return Boolean false if success, string of missing needed element/attribute if failure
*/
public function prepare($config, $context) {
$this->htmlDefinition = $config->getHTMLDefinition();
// Even though this might fail, some unit tests ignore this and
// still test checkNeeded, so be careful. Maybe get rid of that
// dependency.
$result = $this->checkNeeded($config);
if ($result !== false) return $result;
$this->currentNesting =& $context->get('CurrentNesting');
$this->inputTokens =& $context->get('InputTokens');
$this->inputIndex =& $context->get('InputIndex');
return false;
}
/**
* This function checks if the HTML environment
* will work with the Injector: if p tags are not allowed, the
* Auto-Paragraphing injector should not be enabled.
* @param $config Instance of HTMLPurifier_Config
* @param $context Instance of HTMLPurifier_Context
* @return Boolean false if success, string of missing needed element/attribute if failure
*/
public function checkNeeded($config) {
$def = $config->getHTMLDefinition();
foreach ($this->needed as $element => $attributes) {
if (is_int($element)) $element = $attributes;
if (!isset($def->info[$element])) return $element;
if (!is_array($attributes)) continue;
foreach ($attributes as $name) {
if (!isset($def->info[$element]->attr[$name])) return "$element.$name";
}
}
return false;
}
/**
* Tests if the context node allows a certain element
* @param $name Name of element to test for
* @return True if element is allowed, false if it is not
*/
public function allowsElement($name) {
if (!empty($this->currentNesting)) {
$parent_token = array_pop($this->currentNesting);
$this->currentNesting[] = $parent_token;
$parent = $this->htmlDefinition->info[$parent_token->name];
} else {
$parent = $this->htmlDefinition->info_parent_def;
}
if (!isset($parent->child->elements[$name]) || isset($parent->excludes[$name])) {
return false;
}
// check for exclusion
for ($i = count($this->currentNesting) - 2; $i >= 0; $i--) {
$node = $this->currentNesting[$i];
$def = $this->htmlDefinition->info[$node->name];
if (isset($def->excludes[$name])) return false;
}
return true;
}
/**
* Iterator function, which starts with the next token and continues until
* you reach the end of the input tokens.
* @warning Please prevent previous references from interfering with this
* functions by setting $i = null beforehand!
* @param &$i Current integer index variable for inputTokens
* @param &$current Current token variable. Do NOT use $token, as that variable is also a reference
*/
protected function forward(&$i, &$current) {
if ($i === null) $i = $this->inputIndex + 1;
else $i++;
if (!isset($this->inputTokens[$i])) return false;
$current = $this->inputTokens[$i];
return true;
}
/**
* Similar to _forward, but accepts a third parameter $nesting (which
* should be initialized at 0) and stops when we hit the end tag
* for the node $this->inputIndex starts in.
*/
protected function forwardUntilEndToken(&$i, &$current, &$nesting) {
$result = $this->forward($i, $current);
if (!$result) return false;
if ($nesting === null) $nesting = 0;
if ($current instanceof HTMLPurifier_Token_Start) $nesting++;
elseif ($current instanceof HTMLPurifier_Token_End) {
if ($nesting <= 0) return false;
$nesting--;
}
return true;
}
/**
* Iterator function, starts with the previous token and continues until
* you reach the beginning of input tokens.
* @warning Please prevent previous references from interfering with this
* functions by setting $i = null beforehand!
* @param &$i Current integer index variable for inputTokens
* @param &$current Current token variable. Do NOT use $token, as that variable is also a reference
*/
protected function backward(&$i, &$current) {
if ($i === null) $i = $this->inputIndex - 1;
else $i--;
if ($i < 0) return false;
$current = $this->inputTokens[$i];
return true;
}
/**
* Initializes the iterator at the current position. Use in a do {} while;
* loop to force the _forward and _backward functions to start at the
* current location.
* @warning Please prevent previous references from interfering with this
* functions by setting $i = null beforehand!
* @param &$i Current integer index variable for inputTokens
* @param &$current Current token variable. Do NOT use $token, as that variable is also a reference
*/
protected function current(&$i, &$current) {
if ($i === null) $i = $this->inputIndex;
$current = $this->inputTokens[$i];
}
/**
* Handler that is called when a text token is processed
*/
public function handleText(&$token) {}
/**
* Handler that is called when a start or empty token is processed
*/
public function handleElement(&$token) {}
/**
* Handler that is called when an end token is processed
*/
public function handleEnd(&$token) {
$this->notifyEnd($token);
}
/**
* Notifier that is called when an end token is processed
* @note This differs from handlers in that the token is read-only
* @deprecated
*/
public function notifyEnd($token) {}
}
// vim: et sw=4 sts=4
