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Use a Zipper to process MakeWellFormed, removing quadratic behavior.

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Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
This commit is contained in:
Edward Z. Yang
2013-10-13 12:53:51 -07:00
parent 82bcc62058
commit 8f401f769e
10 changed files with 158 additions and 149 deletions
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158
library/HTMLPurifier/Strategy/MakeWellFormed.php
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@@ -21,10 +21,16 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
protected $tokens;
/**
* Current index in $tokens.
* @type int
* Current token.
* @type HTMLPurifier_Token
*/
protected $t;
protected $token;
/**
* Zipper managing the true state.
* @type HTMLPurifier_Zipper
*/
protected $zipper;
/**
* Current nesting of elements.
@@ -67,23 +73,25 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
// used for autoclose early abortion
$global_parent_allowed_elements = $definition->info_parent_def->child->getAllowedElements($config);
$e = $context->get('ErrorCollector', true);
$t = false; // token index
$i = false; // injector index
$token = false; // the current token
list($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->t =& $t;
$this->tokens =& $tokens;
$this->token =& $token;
$this->zipper =& $zipper;
$this->config = $config;
$this->context = $context;
// context variables
$context->register('CurrentNesting', $stack);
$context->register('InputIndex', $t);
$context->register('InputTokens', $tokens);
$context->register('InputZipper', $zipper);
$context->register('CurrentToken', $token);
// -- begin INJECTOR --
@@ -142,32 +150,28 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
// punt ($reprocess = true; continue;) and it does that for us.
// isset is in loop because $tokens size changes during loop exec
for ($t = 0;
$t == 0 || isset($tokens[$t - 1]);
// only increment if we don't need to reprocess
$reprocess ? $reprocess = false : $t++) {
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) && $i >= 0) {
if (is_int($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_to = $this->injectors[$i]->getRewind();
if (is_int($rewind_to) && $rewind_to < $t) {
if ($rewind_to < 0) {
$rewind_to = 0;
}
while ($t > $rewind_to) {
$t--;
$prev = $tokens[$t];
$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($prev->skip[$i]);
$prev->rewind = $i;
if ($prev instanceof HTMLPurifier_Token_Start) {
unset($token->skip[$i]);
$token->rewind = $i;
if ($token instanceof HTMLPurifier_Token_Start) {
array_pop($this->stack);
} elseif ($prev instanceof HTMLPurifier_Token_End) {
$this->stack[] = $prev->start;
} elseif ($token instanceof HTMLPurifier_Token_End) {
$this->stack[] = $token->start;
}
}
}
@@ -175,7 +179,7 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
}
// handle case of document end
if (!isset($tokens[$t])) {
if ($token === NULL) {
// kill processing if stack is empty
if (empty($this->stack)) {
break;
@@ -191,16 +195,14 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
}
// append, don't splice, since this is the end
$tokens[] = new HTMLPurifier_Token_End($top_nesting->name);
$token = new HTMLPurifier_Token_End($top_nesting->name);
// punt!
$reprocess = true;
continue;
}
$token = $tokens[$t];
//echo '<br>'; printTokens($tokens, $t); printTokens($this->stack);
//echo '<br>'; printZipper($zipper, $token);//printTokens($this->stack);
//flush();
// quick-check: if it's not a tag, no need to process
@@ -213,8 +215,10 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
if ($token->rewind !== null && $token->rewind !== $i) {
continue;
}
$injector->handleText($token);
$this->processToken($token, $i);
// XXX fuckup
$r = $token;
$injector->handleText($r);
$token = $this->processToken($r, $i);
$reprocess = true;
break;
}
@@ -243,9 +247,11 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
$ok = true;
} elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) {
// claims to be empty but really is a start tag
$this->swap(new HTMLPurifier_Token_End($token->name));
$this->insertBefore(
new HTMLPurifier_Token_Start($token->name, $token->attr, $token->line, $token->col, $token->armor)
// 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;
@@ -293,7 +299,7 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
$elements = $wrapdef->child->getAllowedElements($config);
if (isset($elements[$token->name]) && isset($parent_elements[$wrapname])) {
$newtoken = new HTMLPurifier_Token_Start($wrapname);
$this->insertBefore($newtoken);
$token = $this->insertBefore($newtoken);
$reprocess = true;
continue;
}
@@ -330,15 +336,6 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
// errors need to be updated
$new_token = new HTMLPurifier_Token_End($parent->name);
$new_token->start = $parent;
if ($carryover) {
$element = clone $parent;
// [TagClosedAuto]
$element->armor['MakeWellFormed_TagClosedError'] = true;
$element->carryover = true;
$this->processToken(array($new_token, $token, $element));
} else {
$this->insertBefore($new_token);
}
// [TagClosedSuppress]
if ($e && !isset($parent->armor['MakeWellFormed_TagClosedError'])) {
if (!$carryover) {
@@ -347,8 +344,17 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
$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 {
$this->remove();
$token = $this->remove();
}
$reprocess = true;
continue;
@@ -366,14 +372,14 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
if ($token->rewind !== null && $token->rewind !== $i) {
continue;
}
$injector->handleElement($token);
$this->processToken($token, $i);
$r = $token;
$injector->handleElement($r);
$token = $this->processToken($r, $i);
$reprocess = true;
break;
}
if (!$reprocess) {
// ah, nothing interesting happened; do normal processing
$this->swap($token);
if ($token instanceof HTMLPurifier_Token_Start) {
$this->stack[] = $token;
} elseif ($token instanceof HTMLPurifier_Token_End) {
@@ -396,16 +402,12 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
if ($e) {
$e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag to text');
}
$this->swap(
new HTMLPurifier_Token_Text(
$generator->generateFromToken($token)
)
);
$token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));
} else {
$this->remove();
if ($e) {
$e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed');
}
$token = $this->remove();
}
$reprocess = true;
continue;
@@ -425,8 +427,9 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
if ($token->rewind !== null && $token->rewind !== $i) {
continue;
}
$injector->handleEnd($token);
$this->processToken($token, $i);
$r = $token;
$injector->handleEnd($r);
$token = $this->processToken($r, $i);
$this->stack[] = $current_parent;
$reprocess = true;
break;
@@ -454,19 +457,15 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
// we didn't find the tag, so remove
if ($skipped_tags === false) {
if ($escape_invalid_tags) {
$this->swap(
new HTMLPurifier_Token_Text(
$generator->generateFromToken($token)
)
);
if ($e) {
$e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text');
}
$token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));
} else {
$this->remove();
if ($e) {
$e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed');
}
$token = $this->remove();
}
$reprocess = true;
continue;
@@ -499,18 +498,17 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
$replace[] = $element;
}
}
$this->processToken($replace);
$token = $this->processToken($replace);
$reprocess = true;
continue;
}
$context->destroy('CurrentNesting');
$context->destroy('InputTokens');
$context->destroy('InputIndex');
$context->destroy('CurrentToken');
$context->destroy('CurrentNesting');
$context->destroy('InputZipper');
unset($this->injectors, $this->stack, $this->tokens, $this->t);
return $tokens;
unset($this->injectors, $this->stack, $this->tokens);
return $zipper->toArray($token);
}
/**
@@ -560,7 +558,7 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
// array(number nodes to delete, new node 1, new node 2, ...)
$delete = array_shift($token);
$old = array_splice($this->tokens, $this->t, $delete, $token);
list($old, $r) = $this->zipper->splice($this->token, $delete, $token);
if ($injector > -1) {
// determine appropriate skips
@@ -571,6 +569,8 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
}
}
return $r;
}
/**
@@ -580,7 +580,9 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
*/
private function insertBefore($token)
{
array_splice($this->tokens, $this->t, 0, array($token));
// NB not $this->zipper->insertBefore(), due to positioning
// differences
return $this->zipper->splice($this->token, 0, array($token))[1];
}
/**
@@ -589,17 +591,7 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
*/
private function remove()
{
array_splice($this->tokens, $this->t, 1);
}
/**
* Swap current token with new token. Cursor points to new token (no
* change). You must reprocess after this.
* @param HTMLPurifier_Token $token
*/
private function swap($token)
{
$this->tokens[$this->t] = $token;
return $this->zipper->delete();
}
}