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<?php

/**

* Takes tokens makes them well-formed (balance end tags, etc.)

* Specification of the armor attributes this strategy uses:

*      - MakeWellFormed_TagClosedError: This armor field is used to

*        suppress tag closed errors for certain tokens [TagClosedSuppress],

*        in particular, if a tag was generated automatically by HTML

*        Purifier, we may rely on our infrastructure to close it for us

*        and shouldn't report an error to the user [TagClosedAuto].

class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy

{

/**

* Array stream of tokens being processed.

* @type HTMLPurifier_Token[]

protected $tokens;

/**

* Current token.

* @type HTMLPurifier_Token

protected $token;

/**

* Zipper managing the true state.

* @type HTMLPurifier_Zipper

protected $zipper;

/**

* Current nesting of elements.

* @type array

protected $stack;

/**

* Injectors active in this stream processing.

* @type HTMLPurifier_Injector[]

protected $injectors;

/**

* Current instance of HTMLPurifier_Config.

* @type HTMLPurifier_Config

protected $config;

/**

* Current instance of HTMLPurifier_Context.

* @type HTMLPurifier_Context

protected $context;

/**

* @param HTMLPurifier_Token[] $tokens

* @param HTMLPurifier_Config $config

* @param HTMLPurifier_Context $context

* @return HTMLPurifier_Token[]

* @throws HTMLPurifier_Exception

public function execute($tokens, $config, $context)

{

$definition = $config->getHTMLDefinition();

// local variables

$generator = new HTMLPurifier_Generator($config, $context);

$escape_invalid_tags = $config->get('Core.EscapeInvalidTags');

// used for autoclose early abortion

$global_parent_allowed_elements = $definition->info_parent_def->child->getAllowedElements($config);

$e = $context->get('ErrorCollector', true);

$i = false; // injector index

list($zipper, $token) = HTMLPurifier_Zipper::fromArray($tokens);

if ($token === NULL) {

return array();

}

$reprocess = false; // whether or not to reprocess the same token

$stack = array();

// member variables

$this->stack =& $stack;

$this->tokens =& $tokens;

$this->token =& $token;

$this->zipper =& $zipper;

$this->config = $config;

$this->context = $context;

// context variables

$context->register('CurrentNesting', $stack);

$context->register('InputZipper', $zipper);

$context->register('CurrentToken', $token);

// -- begin INJECTOR --

$this->injectors = array();

$injectors = $config->getBatch('AutoFormat');

$def_injectors = $definition->info_injector;

$custom_injectors = $injectors['Custom'];

unset($injectors['Custom']); // special case

foreach ($injectors as $injector => $b) {

// XXX: Fix with a legitimate lookup table of enabled filters

if (strpos($injector, '.') !== false) {

continue;

}

$injector = "HTMLPurifier_Injector_$injector";

if (!$b) {

continue;

}

$this->injectors[] = new $injector;

}

foreach ($def_injectors as $injector) {

// assumed to be objects

$this->injectors[] = $injector;

}

foreach ($custom_injectors as $injector) {

if (!$injector) {

continue;

}

if (is_string($injector)) {

$injector = "HTMLPurifier_Injector_$injector";

$injector = new $injector;

}

$this->injectors[] = $injector;

}

// give the injectors references to the definition and context

// variables for performance reasons

foreach ($this->injectors as $ix => $injector) {

$error = $injector->prepare($config, $context);

if (!$error) {

continue;

}

array_splice($this->injectors, $ix, 1); // rm the injector

trigger_error("Cannot enable {$injector->name} injector because $error is not allowed", E_USER_WARNING);

}

// -- end INJECTOR --

// a note on reprocessing:

//      In order to reduce code duplication, whenever some code needs

//      to make HTML changes in order to make things "correct", the

//      new HTML gets sent through the purifier, regardless of its

//      status. This means that if we add a start token, because it

//      was totally necessary, we don't have to update nesting; we just

//      punt ($reprocess = true; continue;) and it does that for us.

// isset is in loop because $tokens size changes during loop exec

for (;;

// only increment if we don't need to reprocess

$reprocess ? $reprocess = false : $token = $zipper->next($token)) {

// check for a rewind

if (is_int($i)) {

// possibility: disable rewinding if the current token has a

// rewind set on it already. This would offer protection from

// infinite loop, but might hinder some advanced rewinding.

$rewind_offset = $this->injectors[$i]->getRewindOffset();

if (is_int($rewind_offset)) {

for ($j = 0; $j < $rewind_offset; $j++) {

if (empty($zipper->front)) break;

$token = $zipper->prev($token);

// indicate that other injectors should not process this token,

// but we need to reprocess it

unset($token->skip[$i]);

$token->rewind = $i;

if ($token instanceof HTMLPurifier_Token_Start) {

array_pop($this->stack);

} elseif ($token instanceof HTMLPurifier_Token_End) {

$this->stack[] = $token->start;

}

$i = false;

}

// handle case of document end

if ($token === NULL) {

// kill processing if stack is empty

if (empty($this->stack)) {

break;

}

// peek

$top_nesting = array_pop($this->stack);

$this->stack[] = $top_nesting;

// send error [TagClosedSuppress]

if ($e && !isset($top_nesting->armor['MakeWellFormed_TagClosedError'])) {

$e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by document end', $top_nesting);

}

// append, don't splice, since this is the end

$token = new HTMLPurifier_Token_End($top_nesting->name);

// punt!

$reprocess = true;

continue;

}

//echo '<br>'; printZipper($zipper, $token);//printTokens($this->stack);

//flush();

// quick-check: if it's not a tag, no need to process

if (empty($token->is_tag)) {

if ($token instanceof HTMLPurifier_Token_Text) {

foreach ($this->injectors as $i => $injector) {

if (isset($token->skip[$i])) {

continue;

}

if ($token->rewind !== null && $token->rewind !== $i) {

continue;

}

// XXX fuckup

$r = $token;

$injector->handleText($r);

$token = $this->processToken($r, $i);

$reprocess = true;

break;

}

// another possibility is a comment

continue;

}

if (isset($definition->info[$token->name])) {

$type = $definition->info[$token->name]->child->type;

} else {

$type = false; // Type is unknown, treat accordingly

}

// quick tag checks: anything that's *not* an end tag

$ok = false;

if ($type === 'empty' && $token instanceof HTMLPurifier_Token_Start) {

// claims to be a start tag but is empty

$token = new HTMLPurifier_Token_Empty(

$token->name,

$token->attr,

$token->line,

$token->col,

$token->armor

);

$ok = true;

} elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) {

// claims to be empty but really is a start tag

// NB: this assignment is required

$old_token = $token;

$token = new HTMLPurifier_Token_End($token->name);

$token = $this->insertBefore(

new HTMLPurifier_Token_Start($old_token->name, $old_token->attr, $old_token->line, $old_token->col, $old_token->armor)

);

// punt (since we had to modify the input stream in a non-trivial way)

$reprocess = true;

continue;

} elseif ($token instanceof HTMLPurifier_Token_Empty) {

// real empty token

$ok = true;

} elseif ($token instanceof HTMLPurifier_Token_Start) {

// start tag

// ...unless they also have to close their parent

if (!empty($this->stack)) {

// Performance note: you might think that it's rather

// inefficient, recalculating the autoclose information

// for every tag that a token closes (since when we

// do an autoclose, we push a new token into the

// stream and then /process/ that, before

// re-processing this token.)  But this is

// necessary, because an injector can make an

// arbitrary transformations to the autoclosing

// tokens we introduce, so things may have changed

// in the meantime.  Also, doing the inefficient thing is

// "easy" to reason about (for certain perverse definitions

// of "easy")

$parent = array_pop($this->stack);

$this->stack[] = $parent;

$parent_def = null;

$parent_elements = null;

$autoclose = false;

if (isset($definition->info[$parent->name])) {

$parent_def = $definition->info[$parent->name];

$parent_elements = $parent_def->child->getAllowedElements($config);

$autoclose = !isset($parent_elements[$token->name]);

}

if ($autoclose && $definition->info[$token->name]->wrap) {

// Check if an element can be wrapped by another

// element to make it valid in a context (for

// example, <ul><ul> needs a <li> in between)

$wrapname = $definition->info[$token->name]->wrap;

$wrapdef = $definition->info[$wrapname];

$elements = $wrapdef->child->getAllowedElements($config);

if (isset($elements[$token->name]) && isset($parent_elements[$wrapname])) {

$newtoken = new HTMLPurifier_Token_Start($wrapname);

$token = $this->insertBefore($newtoken);

$reprocess = true;

continue;

}

$carryover = false;

if ($autoclose && $parent_def->formatting) {

$carryover = true;

}

if ($autoclose) {

// check if this autoclose is doomed to fail

// (this rechecks $parent, which his harmless)

$autoclose_ok = isset($global_parent_allowed_elements[$token->name]);

if (!$autoclose_ok) {

foreach ($this->stack as $ancestor) {

$elements = $definition->info[$ancestor->name]->child->getAllowedElements($config);

if (isset($elements[$token->name])) {

$autoclose_ok = true;

break;

}

if ($definition->info[$token->name]->wrap) {

$wrapname = $definition->info[$token->name]->wrap;

$wrapdef = $definition->info[$wrapname];

$wrap_elements = $wrapdef->child->getAllowedElements($config);

if (isset($wrap_elements[$token->name]) && isset($elements[$wrapname])) {

$autoclose_ok = true;

break;

}

if ($autoclose_ok) {

// errors need to be updated

$new_token = new HTMLPurifier_Token_End($parent->name);

$new_token->start = $parent;

// [TagClosedSuppress]

if ($e && !isset($parent->armor['MakeWellFormed_TagClosedError'])) {

if (!$carryover) {

$e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent);

} else {

$e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag carryover', $parent);

}

if ($carryover) {

$element = clone $parent;

// [TagClosedAuto]

$element->armor['MakeWellFormed_TagClosedError'] = true;

$element->carryover = true;

$token = $this->processToken(array($new_token, $token, $element));

} else {

$token = $this->insertBefore($new_token);

}

} else {

$token = $this->remove();

}

$reprocess = true;

continue;

}

$ok = true;

}

if ($ok) {

foreach ($this->injectors as $i => $injector) {

if (isset($token->skip[$i])) {

continue;

}

if ($token->rewind !== null && $token->rewind !== $i) {

continue;

}

$r = $token;

$injector->handleElement($r);

$token = $this->processToken($r, $i);

$reprocess = true;

break;

}

if (!$reprocess) {

// ah, nothing interesting happened; do normal processing

if ($token instanceof HTMLPurifier_Token_Start) {

$this->stack[] = $token;

} elseif ($token instanceof HTMLPurifier_Token_End) {

throw new HTMLPurifier_Exception(

'Improper handling of end tag in start code; possible error in MakeWellFormed'

);

}

continue;

}

// sanity check: we should be dealing with a closing tag

if (!$token instanceof HTMLPurifier_Token_End) {

throw new HTMLPurifier_Exception('Unaccounted for tag token in input stream, bug in HTML Purifier');

}

// make sure that we have something open

if (empty($this->stack)) {

if ($escape_invalid_tags) {

if ($e) {

$e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag to text');

}

$token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));

} else {

if ($e) {

$e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed');

}

$token = $this->remove();

}

$reprocess = true;

continue;

}

// first, check for the simplest case: everything closes neatly.

// Eventually, everything passes through here; if there are problems

// we modify the input stream accordingly and then punt, so that

// the tokens get processed again.

$current_parent = array_pop($this->stack);

if ($current_parent->name == $token->name) {

$token->start = $current_parent;

foreach ($this->injectors as $i => $injector) {

if (isset($token->skip[$i])) {

continue;

}

if ($token->rewind !== null && $token->rewind !== $i) {

continue;

}

$r = $token;

$injector->handleEnd($r);

$token = $this->processToken($r, $i);

$this->stack[] = $current_parent;

$reprocess = true;

break;

}

continue;

}

// okay, so we're trying to close the wrong tag

// undo the pop previous pop

$this->stack[] = $current_parent;

// scroll back the entire nest, trying to find our tag.

// (feature could be to specify how far you'd like to go)

$size = count($this->stack);

// -2 because -1 is the last element, but we already checked that

$skipped_tags = false;

for ($j = $size - 2; $j >= 0; $j--) {

if ($this->stack[$j]->name == $token->name) {

$skipped_tags = array_slice($this->stack, $j);

break;

}

// we didn't find the tag, so remove

if ($skipped_tags === false) {

if ($escape_invalid_tags) {

if ($e) {

$e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text');

}

$token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));

} else {

if ($e) {

$e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed');

}

$token = $this->remove();

}

$reprocess = true;

continue;

}

// do errors, in REVERSE $j order: a,b,c with </a></b></c>

$c = count($skipped_tags);

if ($e) {

for ($j = $c - 1; $j > 0; $j--) {

// notice we exclude $j == 0, i.e. the current ending tag, from

// the errors... [TagClosedSuppress]

if (!isset($skipped_tags[$j]->armor['MakeWellFormed_TagClosedError'])) {

$e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by element end', $skipped_tags[$j]);

}

// insert tags, in FORWARD $j order: c,b,a with </a></b></c>

$replace = array($token);

for ($j = 1; $j < $c; $j++) {

// ...as well as from the insertions

$new_token = new HTMLPurifier_Token_End($skipped_tags[$j]->name);

$new_token->start = $skipped_tags[$j];

array_unshift($replace, $new_token);

if (isset($definition->info[$new_token->name]) && $definition->info[$new_token->name]->formatting) {

// [TagClosedAuto]

$element = clone $skipped_tags[$j];

$element->carryover = true;

$element->armor['MakeWellFormed_TagClosedError'] = true;

$replace[] = $element;

}

$token = $this->processToken($replace);

$reprocess = true;

continue;

}

$context->destroy('CurrentToken');

$context->destroy('CurrentNesting');

$context->destroy('InputZipper');

unset($this->injectors, $this->stack, $this->tokens);

return $zipper->toArray($token);

}

/**

* Processes arbitrary token values for complicated substitution patterns.

* In general:

* If $token is an array, it is a list of tokens to substitute for the

* current token. These tokens then get individually processed. If there

* is a leading integer in the list, that integer determines how many

* tokens from the stream should be removed.

* If $token is a regular token, it is swapped with the current token.

* If $token is false, the current token is deleted.

* If $token is an integer, that number of tokens (with the first token

* being the current one) will be deleted.

* @param HTMLPurifier_Token|array|int|bool $token Token substitution value

* @param HTMLPurifier_Injector|int $injector Injector that performed the substitution; default is if

*        this is not an injector related operation.

* @throws HTMLPurifier_Exception

protected function processToken($token, $injector = -1)

{

// normalize forms of token

if (is_object($token)) {

$token = array(1, $token);

}

if (is_int($token)) {

$token = array($token);

}

if ($token === false) {

$token = array(1);

}

if (!is_array($token)) {

throw new HTMLPurifier_Exception('Invalid token type from injector');

}

if (!is_int($token[0])) {

array_unshift($token, 1);

}

if ($token[0] === 0) {

throw new HTMLPurifier_Exception('Deleting zero tokens is not valid');

}

// $token is now an array with the following form:

// array(number nodes to delete, new node 1, new node 2, ...)

$delete = array_shift($token);

list($old, $r) = $this->zipper->splice($this->token, $delete, $token);

if ($injector > -1) {

// determine appropriate skips

$oldskip = isset($old[0]) ? $old[0]->skip : array();

foreach ($token as $object) {

$object->skip = $oldskip;

$object->skip[$injector] = true;

}

return $r;

}

/**

* Inserts a token before the current token. Cursor now points to

* this token.  You must reprocess after this.

* @param HTMLPurifier_Token $token

private function insertBefore($token)

{

// NB not $this->zipper->insertBefore(), due to positioning

// differences

$splice = $this->zipper->splice($this->token, 0, array($token));

return $splice[1];

}

/**

* Removes current token. Cursor now points to new token occupying previously

* occupied space.  You must reprocess after this.

private function remove()

{

return $this->zipper->delete();

}

// vim: et sw=4 sts=4

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