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Diffstat (limited to 'vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/FixNesting.php')
| -rw-r--r-- | vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/FixNesting.php | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/FixNesting.php b/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/FixNesting.php new file mode 100644 index 000000000..6fa673db9 --- /dev/null +++ b/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/FixNesting.php @@ -0,0 +1,181 @@ +<?php + +/** + * Takes a well formed list of tokens and fixes their nesting. + * + * HTML elements dictate which elements are allowed to be their children, + * for example, you can't have a p tag in a span tag. Other elements have + * much more rigorous definitions: tables, for instance, require a specific + * order for their elements. There are also constraints not expressible by + * document type definitions, such as the chameleon nature of ins/del + * tags and global child exclusions. + * + * The first major objective of this strategy is to iterate through all + * the nodes and determine whether or not their children conform to the + * element's definition. If they do not, the child definition may + * optionally supply an amended list of elements that is valid or + * require that the entire node be deleted (and the previous node + * rescanned). + * + * The second objective is to ensure that explicitly excluded elements of + * an element do not appear in its children. Code that accomplishes this + * task is pervasive through the strategy, though the two are distinct tasks + * and could, theoretically, be seperated (although it's not recommended). + * + * @note Whether or not unrecognized children are silently dropped or + * translated into text depends on the child definitions. + * + * @todo Enable nodes to be bubbled out of the structure. This is + * easier with our new algorithm. + */ + +class HTMLPurifier_Strategy_FixNesting extends HTMLPurifier_Strategy +{ + + /** + * @param HTMLPurifier_Token[] $tokens + * @param HTMLPurifier_Config $config + * @param HTMLPurifier_Context $context + * @return array|HTMLPurifier_Token[] + */ + public function execute($tokens, $config, $context) + { + + //####################################################################// + // Pre-processing + + // O(n) pass to convert to a tree, so that we can efficiently + // refer to substrings + $top_node = HTMLPurifier_Arborize::arborize($tokens, $config, $context); + + // get a copy of the HTML definition + $definition = $config->getHTMLDefinition(); + + $excludes_enabled = !$config->get('Core.DisableExcludes'); + + // setup the context variable 'IsInline', for chameleon processing + // is 'false' when we are not inline, 'true' when it must always + // be inline, and an integer when it is inline for a certain + // branch of the document tree + $is_inline = $definition->info_parent_def->descendants_are_inline; + $context->register('IsInline', $is_inline); + + // setup error collector + $e =& $context->get('ErrorCollector', true); + + //####################################################################// + // Loop initialization + + // stack that contains all elements that are excluded + // it is organized by parent elements, similar to $stack, + // but it is only populated when an element with exclusions is + // processed, i.e. there won't be empty exclusions. + $exclude_stack = array($definition->info_parent_def->excludes); + + // variable that contains the start token while we are processing + // nodes. This enables error reporting to do its job + $node = $top_node; + // dummy token + list($token, $d) = $node->toTokenPair(); + $context->register('CurrentNode', $node); + $context->register('CurrentToken', $token); + + //####################################################################// + // Loop + + // We need to implement a post-order traversal iteratively, to + // avoid running into stack space limits. This is pretty tricky + // to reason about, so we just manually stack-ify the recursive + // variant: + // + // function f($node) { + // foreach ($node->children as $child) { + // f($child); + // } + // validate($node); + // } + // + // Thus, we will represent a stack frame as array($node, + // $is_inline, stack of children) + // e.g. array_reverse($node->children) - already processed + // children. + + $parent_def = $definition->info_parent_def; + $stack = array( + array($top_node, + $parent_def->descendants_are_inline, + $parent_def->excludes, // exclusions + 0) + ); + + while (!empty($stack)) { + list($node, $is_inline, $excludes, $ix) = array_pop($stack); + // recursive call + $go = false; + $def = empty($stack) ? $definition->info_parent_def : $definition->info[$node->name]; + while (isset($node->children[$ix])) { + $child = $node->children[$ix++]; + if ($child instanceof HTMLPurifier_Node_Element) { + $go = true; + $stack[] = array($node, $is_inline, $excludes, $ix); + $stack[] = array($child, + // ToDo: I don't think it matters if it's def or + // child_def, but double check this... + $is_inline || $def->descendants_are_inline, + empty($def->excludes) ? $excludes + : array_merge($excludes, $def->excludes), + 0); + break; + } + }; + if ($go) continue; + list($token, $d) = $node->toTokenPair(); + // base case + if ($excludes_enabled && isset($excludes[$node->name])) { + $node->dead = true; + if ($e) $e->send(E_ERROR, 'Strategy_FixNesting: Node excluded'); + } else { + // XXX I suppose it would be slightly more efficient to + // avoid the allocation here and have children + // strategies handle it + $children = array(); + foreach ($node->children as $child) { + if (!$child->dead) $children[] = $child; + } + $result = $def->child->validateChildren($children, $config, $context); + if ($result === true) { + // nop + $node->children = $children; + } elseif ($result === false) { + $node->dead = true; + if ($e) $e->send(E_ERROR, 'Strategy_FixNesting: Node removed'); + } else { + $node->children = $result; + if ($e) { + // XXX This will miss mutations of internal nodes. Perhaps defer to the child validators + if (empty($result) && !empty($children)) { + $e->send(E_ERROR, 'Strategy_FixNesting: Node contents removed'); + } else if ($result != $children) { + $e->send(E_WARNING, 'Strategy_FixNesting: Node reorganized'); + } + } + } + } + } + + //####################################################################// + // Post-processing + + // remove context variables + $context->destroy('IsInline'); + $context->destroy('CurrentNode'); + $context->destroy('CurrentToken'); + + //####################################################################// + // Return + + return HTMLPurifier_Arborize::flatten($node, $config, $context); + } +} + +// vim: et sw=4 sts=4 |