lexbor/selectors-adapted/selectors.c

/*
 * Copyright (C) 2021-2024 Alexander Borisov
 *
 * Author: Alexander Borisov <borisov@lexbor.com>
 * Adapted for PHP + libxml2 by: Niels Dossche <nielsdos@php.net>
 * Based on Lexbor 2.4.0 (upstream commit e9d35f6384de7bd8c1b79e7111bc3a44f8822967)
 */

#include <libxml/xmlstring.h>
#include <libxml/dict.h>
#include <Zend/zend.h>
#include <Zend/zend_operators.h>
#include <Zend/zend_API.h>
#include <php.h>

#include "lexbor/selectors-adapted/selectors.h"
#include "../../../namespace_compat.h"
#include "../../../domexception.h"
#include "../../../php_dom.h"

#include <math.h>

/* Note: casting and then comparing is a bit faster on my i7-4790 */
#define CMP_NODE_TYPE(node, ty) ((unsigned char) (node)->type == ty)

typedef struct dom_lxb_str_wrapper {
	lexbor_str_t str;
	bool should_free;
} dom_lxb_str_wrapper;

static void dom_lxb_str_wrapper_release(dom_lxb_str_wrapper *wrapper)
{
	if (wrapper->should_free) {
		xmlFree(wrapper->str.data);
	}
}

static zend_always_inline bool lxb_selectors_adapted_is_matchable_child(const xmlNode *node)
{
	return CMP_NODE_TYPE(node, XML_ELEMENT_NODE);
}

static zend_always_inline bool lxb_selectors_adapted_cmp_local_name_literal(const xmlNode *node, const char *name)
{
	return strcmp((const char *) node->name, name) == 0;
}

static zend_always_inline bool lxb_selectors_adapted_cmp_ns(const xmlNode *a, const xmlNode *b)
{
	/* Namespace URIs are not interned, hence a->href != b->href. */
	return a->ns == b->ns || (a->ns != NULL && b->ns != NULL && xmlStrEqual(a->ns->href, b->ns->href));
}

static zend_always_inline bool lxb_selectors_adapted_cmp_local_name_id(const xmlNode *node, const lxb_selectors_adapted_id *id)
{
	uintptr_t ptr = (uintptr_t) node->name;
	if (id->interned && (ptr & (ZEND_MM_ALIGNMENT - 1)) != 0) {
		/* It cannot be a heap-allocated string because the pointer is not properly aligned for a heap allocation.
		 * Therefore, it must be interned into the dictionary pool. */
		return node->name == id->name;
	}

	return strcmp((const char *) node->name, (const char *) id->name) == 0;
}

static zend_always_inline const xmlAttr *lxb_selectors_adapted_attr(const xmlNode *node, const lxb_char_t *name)
{
	const xmlAttr *attr = xmlHasProp(node, (const xmlChar *) name);
	if (attr != NULL && attr->ns != NULL) {
		return NULL;
	}
	return attr;
}

static zend_always_inline bool lxb_selectors_adapted_has_attr(const xmlNode *node, const char *name)
{
	return lxb_selectors_adapted_attr(node, (const lxb_char_t *) name) != NULL;
}

static zend_always_inline dom_lxb_str_wrapper lxb_selectors_adapted_attr_value(const xmlAttr *attr)
{
	dom_lxb_str_wrapper ret;
	ret.str.data = (lxb_char_t *) php_libxml_attr_value(attr, &ret.should_free);
	ret.str.length = strlen((const char *) ret.str.data);
	return ret;
}

static void lxb_selectors_adapted_set_entry_id_ex(lxb_selectors_entry_t *entry, const lxb_css_selector_t *selector, const xmlNode *node)
{
	if (node->doc != NULL && node->doc->dict != NULL) {
		const xmlChar *interned = xmlDictExists(node->doc->dict, selector->name.data, selector->name.length);
		if (interned != NULL) {
			entry->id.name = interned;
			entry->id.interned = true;
			return;
		}
	}

	entry->id.name = selector->name.data;
	entry->id.interned = false;
}

static zend_always_inline void lxb_selectors_adapted_set_entry_id(lxb_selectors_entry_t *entry, const lxb_css_selector_t *selector, const xmlNode *node)
{
	if (entry->id.name == NULL) {
		lxb_selectors_adapted_set_entry_id_ex(entry, selector, node);
	}
}

static lxb_status_t
lxb_selectors_state_tree(lxb_selectors_t *selectors, const xmlNode *root,
						 const lxb_css_selector_list_t *list);

static lxb_status_t
lxb_selectors_state_run(lxb_selectors_t *selectors, const xmlNode *node,
						const lxb_css_selector_list_t *list);

static lxb_selectors_entry_t *
lxb_selectors_state_find(lxb_selectors_t *selectors,
						 lxb_selectors_entry_t *entry);

static lxb_selectors_entry_t *
lxb_selectors_state_find_check(lxb_selectors_t *selectors, const xmlNode *node,
							   const lxb_css_selector_t *selector,
							   lxb_selectors_entry_t *entry);

static lxb_selectors_entry_t *
lxb_selectors_state_pseudo_class_function(lxb_selectors_t *selectors,
										  lxb_selectors_entry_t *entry);

static const xmlNode *
lxb_selectors_next_node(lxb_selectors_nested_t *main);

static const xmlNode *
lxb_selectors_state_has_relative(const xmlNode *node,
								 const lxb_css_selector_t *selector);

static lxb_selectors_entry_t *
lxb_selectors_state_after_find_has(lxb_selectors_t *selectors,
								   lxb_selectors_entry_t *entry);

static lxb_selectors_entry_t *
lxb_selectors_state_after_find(lxb_selectors_t *selectors,
							   lxb_selectors_entry_t *entry);

static lxb_selectors_entry_t *
lxb_selectors_state_after_nth_child(lxb_selectors_t *selectors,
									lxb_selectors_entry_t *entry);

static bool
lxb_selectors_match(lxb_selectors_t *selectors, lxb_selectors_entry_t *entry,
					const lxb_css_selector_t *selector, const xmlNode *node);

static bool
lxb_selectors_match_element(const lxb_css_selector_t *selector,
							const xmlNode *node, lxb_selectors_entry_t *entry);

static bool
lxb_selectors_match_id(const lxb_css_selector_t *selector, const xmlNode *node, bool quirks);

static bool
lxb_selectors_match_class(const lexbor_str_t *target, const lexbor_str_t *src,
						  bool quirks);

static bool
lxb_selectors_match_attribute(const lxb_css_selector_t *selector,
							  const xmlNode *node, lxb_selectors_entry_t *entry);

static bool
lxb_selectors_pseudo_class(const lxb_css_selector_t *selector,
						   const xmlNode *node);

static bool
lxb_selectors_pseudo_class_function(const lxb_css_selector_t *selector,
									const xmlNode *node);

static bool
lxb_selectors_pseudo_element(const lxb_css_selector_t *selector,
							 const xmlNode *node);

static bool
lxb_selectors_pseudo_class_disabled(const xmlNode *node);

static bool
lxb_selectors_pseudo_class_first_child(const xmlNode *node);

static bool
lxb_selectors_pseudo_class_first_of_type(const xmlNode *node);

static bool
lxb_selectors_pseudo_class_last_child(const xmlNode *node);

static bool
lxb_selectors_pseudo_class_last_of_type(const xmlNode *node);

static bool
lxb_selectors_pseudo_class_read_write(const xmlNode *node);

static bool
lxb_selectors_anb_calc(const lxb_css_selector_anb_of_t *anb, size_t index);

static lxb_status_t
lxb_selectors_cb_ok(const xmlNode *node,
					lxb_css_selector_specificity_t spec, void *ctx);

static lxb_status_t
lxb_selectors_cb_not(const xmlNode *node,
					 lxb_css_selector_specificity_t spec, void *ctx);


lxb_status_t
lxb_selectors_init(lxb_selectors_t *selectors)
{
	lxb_status_t status;

	selectors->objs = lexbor_dobject_create();
	status = lexbor_dobject_init(selectors->objs,
								 128, sizeof(lxb_selectors_entry_t));
	if (status != LXB_STATUS_OK) {
		return status;
	}

	selectors->nested = lexbor_dobject_create();
	status = lexbor_dobject_init(selectors->nested,
								 64, sizeof(lxb_selectors_nested_t));
	if (status != LXB_STATUS_OK) {
		return status;
	}

	selectors->options = LXB_SELECTORS_OPT_DEFAULT;

	return LXB_STATUS_OK;
}

void
lxb_selectors_clean(lxb_selectors_t *selectors)
{
	lexbor_dobject_clean(selectors->objs);
	lexbor_dobject_clean(selectors->nested);
}

void
lxb_selectors_destroy(lxb_selectors_t *selectors)
{
	selectors->objs = lexbor_dobject_destroy(selectors->objs, true);
	selectors->nested = lexbor_dobject_destroy(selectors->nested, true);
}

lxb_inline const xmlNode *
lxb_selectors_descendant(lxb_selectors_t *selectors,
						 lxb_selectors_entry_t *entry,
						 const lxb_css_selector_t *selector,
						 const xmlNode *node)
{
	node = node->parent;

	while (node != NULL) {
		if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE)
			&& lxb_selectors_match(selectors, entry, selector, node))
		{
			return node;
		}

		node = node->parent;
	}

	return NULL;
}

lxb_inline const xmlNode *
lxb_selectors_close(lxb_selectors_t *selectors, lxb_selectors_entry_t *entry,
					const lxb_css_selector_t *selector, const xmlNode *node)
{
	if (lxb_selectors_match(selectors, entry, selector, node)) {
		return node;
	}

	return NULL;
}

lxb_inline const xmlNode *
lxb_selectors_child(lxb_selectors_t *selectors, lxb_selectors_entry_t *entry,
					const lxb_css_selector_t *selector, const xmlNode *root)
{
	root = root->parent;

	if (root != NULL && CMP_NODE_TYPE(root, XML_ELEMENT_NODE)
		&& lxb_selectors_match(selectors, entry, selector, root))
	{
		return root;
	}

	return NULL;
}

lxb_inline const xmlNode *
lxb_selectors_sibling(lxb_selectors_t *selectors, lxb_selectors_entry_t *entry,
					  const lxb_css_selector_t *selector, const xmlNode *node)
{
	node = node->prev;

	while (node != NULL) {
		if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
			if (lxb_selectors_match(selectors, entry, selector, node)) {
				return node;
			}

			return NULL;
		}

		node = node->prev;
	}

	return NULL;
}

lxb_inline const xmlNode *
lxb_selectors_following(lxb_selectors_t *selectors, lxb_selectors_entry_t *entry,
						const lxb_css_selector_t *selector, const xmlNode *node)
{
	node = node->prev;

	while (node != NULL) {
		if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE) &&
			lxb_selectors_match(selectors, entry, selector, node))
		{
			return node;
		}

		node = node->prev;
	}

	return NULL;
}

lxb_status_t
lxb_selectors_find(lxb_selectors_t *selectors, const xmlNode *root,
				   const lxb_css_selector_list_t *list,
				   lxb_selectors_cb_f cb, void *ctx)
{
	lxb_selectors_entry_t *entry;
	lxb_selectors_nested_t nested;

	entry = lexbor_dobject_calloc(selectors->objs);

	entry->combinator = LXB_CSS_SELECTOR_COMBINATOR_CLOSE;
	entry->selector = list->last;

	nested.parent = NULL;
	nested.entry = entry;
	nested.cb = cb;
	nested.ctx = ctx;

	selectors->current = &nested;
	selectors->status = LXB_STATUS_OK;

	return lxb_selectors_state_tree(selectors, root, list);
}

lxb_status_t
lxb_selectors_match_node(lxb_selectors_t *selectors, const xmlNode *node,
						 const lxb_css_selector_list_t *list,
						 lxb_selectors_cb_f cb, void *ctx)
{
	lxb_status_t status;
	lxb_selectors_entry_t *entry;
	lxb_selectors_nested_t nested;

	if (!CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
		return LXB_STATUS_OK;
	}

	entry = lexbor_dobject_calloc(selectors->objs);

	entry->combinator = LXB_CSS_SELECTOR_COMBINATOR_CLOSE;
	entry->selector = list->last;

	nested.parent = NULL;
	nested.entry = entry;
	nested.cb = cb;
	nested.ctx = ctx;

	selectors->current = &nested;
	selectors->status = LXB_STATUS_OK;

	status = lxb_selectors_state_run(selectors, node, list);

	lxb_selectors_clean(selectors);

	return status;
}

static lxb_status_t
lxb_selectors_state_tree(lxb_selectors_t *selectors, const xmlNode *root,
						 const lxb_css_selector_list_t *list)
{
	lxb_status_t status;
	const xmlNode *node;

#if 0
	if (selectors->options & LXB_SELECTORS_OPT_MATCH_ROOT) {
		node = root;

		if (CMP_NODE_TYPE(node, XML_DOCUMENT_NODE) || CMP_NODE_TYPE(node, XML_HTML_DOCUMENT_NODE)
			 || CMP_NODE_TYPE(node, XML_DOCUMENT_FRAG_NODE)) {
			node = root->children;
		}
	}
	else
#endif
	{
		node = root->children;
	}

	if (node == NULL) {
		goto out;
	}

	do {
		if (!CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
			goto next;
		}

		status = lxb_selectors_state_run(selectors, node, list);
		if (status != LXB_STATUS_OK) {
			if (status == LXB_STATUS_STOP) {
				break;
			}

			lxb_selectors_clean(selectors);

			return status;
		}

		if (node->children != NULL) {
			node = node->children;
		}
		else {

		next:

			while (node != root && node->next == NULL) {
				node = node->parent;
			}

			if (node == root) {
				break;
			}

			node = node->next;
		}
	}
	while (true);

out:
	lxb_selectors_clean(selectors);

	return LXB_STATUS_OK;
}

static lxb_status_t
lxb_selectors_state_run(lxb_selectors_t *selectors, const xmlNode *node,
						const lxb_css_selector_list_t *list)
{
	lxb_selectors_entry_t *entry;

	entry = selectors->current->entry;

	entry->node = node;
	selectors->state = lxb_selectors_state_find;
	selectors->first = entry;

again:

	do {
		entry = selectors->state(selectors, entry);
	}
	while (entry != NULL);

	if (selectors->current->parent != NULL
		&& selectors->status == LXB_STATUS_OK)
	{
		entry = selectors->current->entry;
		selectors->state = selectors->current->return_state;

		goto again;
	}

	return selectors->status;
}

static lxb_selectors_entry_t *
lxb_selectors_state_find(lxb_selectors_t *selectors,
						 lxb_selectors_entry_t *entry)
{
	const xmlNode *node;
	lxb_selectors_entry_t *next;
	const lxb_css_selector_t *selector;
	const lxb_css_selector_anb_of_t *anb;
	const lxb_css_selector_pseudo_t *pseudo;

	selector = entry->selector;

	if (selector->type == LXB_CSS_SELECTOR_TYPE_PSEUDO_CLASS_FUNCTION) {
		pseudo = &selector->u.pseudo;

		/* Optimizing. */

		switch (pseudo->type) {
			case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_CHILD:
			case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_CHILD:
				anb = pseudo->data;

				if (anb->of != NULL) {
					break;
				}

				goto godoit;

			case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_OF_TYPE:
			case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_OF_TYPE:
				goto godoit;

			default:
				break;
		}

		if (entry->nested == NULL) {
			next = lexbor_dobject_calloc(selectors->objs);

			next->combinator = LXB_CSS_SELECTOR_COMBINATOR_CLOSE;

			entry->nested = lexbor_dobject_calloc(selectors->nested);

			entry->nested->entry = next;
			entry->nested->parent = selectors->current;
		}

		selectors->state = lxb_selectors_state_pseudo_class_function;
		selectors->current->last = entry;
		selectors->current = entry->nested;

		next = entry->nested->entry;
		next->node = entry->node;

		return next;
	}

godoit:

	switch (entry->combinator) {
		case LXB_CSS_SELECTOR_COMBINATOR_DESCENDANT:
			node = lxb_selectors_descendant(selectors, entry,
											selector, entry->node);
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_CLOSE:
			node = lxb_selectors_close(selectors, entry,
									   selector, entry->node);
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_CHILD:
			node = lxb_selectors_child(selectors, entry,
									   selector, entry->node);
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_SIBLING:
			node = lxb_selectors_sibling(selectors, entry,
										 selector, entry->node);
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_FOLLOWING:
			node = lxb_selectors_following(selectors, entry,
										   selector, entry->node);
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_CELL:
		default:
			selectors->status = LXB_STATUS_ERROR;
			return NULL;
	}

	return lxb_selectors_state_find_check(selectors, node, selector, entry);
}

static lxb_selectors_entry_t *
lxb_selectors_state_find_check(lxb_selectors_t *selectors, const xmlNode *node,
							   const lxb_css_selector_t *selector,
							   lxb_selectors_entry_t *entry)
{
	lxb_selectors_entry_t *next;
	lxb_selectors_nested_t *current;

	if (node == NULL) {

	try_next:

		if (entry->next == NULL) {

		try_next_list:

			if (selector->list->next == NULL) {
				return NULL;
			}

			/*
			 * Try the following selectors from the selector list.
			 */

			if (entry->following != NULL) {
				entry->following->node = entry->node;

				if (selectors->current->parent == NULL) {
					selectors->first = entry->following;
				}

				return entry->following;
			}

			next = lexbor_dobject_calloc(selectors->objs);

			next->combinator = LXB_CSS_SELECTOR_COMBINATOR_CLOSE;
			next->selector = selector->list->next->last;
			next->node = entry->node;

			entry->following = next;

			if (selectors->current->parent == NULL) {
				selectors->first = next;
			}

			return next;
		}

		do {
			entry = entry->next;

			while (entry->combinator == LXB_CSS_SELECTOR_COMBINATOR_CLOSE) {
				if (entry->next == NULL) {
					selector = entry->selector;
					goto try_next;
				}

				entry = entry->next;
			}

			switch (entry->combinator) {
				case LXB_CSS_SELECTOR_COMBINATOR_DESCENDANT:
					node = entry->node->parent;

					if (node == NULL
						|| !CMP_NODE_TYPE(node, XML_ELEMENT_NODE))
					{
						node = NULL;
					}

					break;

				case LXB_CSS_SELECTOR_COMBINATOR_FOLLOWING:
					node = entry->node->prev;
					break;

				case LXB_CSS_SELECTOR_COMBINATOR_SIBLING:
				case LXB_CSS_SELECTOR_COMBINATOR_CHILD:
				case LXB_CSS_SELECTOR_COMBINATOR_CLOSE:
					node = NULL;
					break;

				case LXB_CSS_SELECTOR_COMBINATOR_CELL:
				default:
					selectors->status = LXB_STATUS_ERROR;
					return NULL;
			}
		}
		while (node == NULL);

		entry->node = node;

		return entry;
	}

	if (selector->prev == NULL) {
		current = selectors->current;

		selectors->status = current->cb(current->entry->node,
										selector->list->specificity,
										current->ctx);

		if ((selectors->options & LXB_SELECTORS_OPT_MATCH_FIRST) == 0
			&& current->parent == NULL)
		{
			if (selectors->status == LXB_STATUS_OK) {
				entry = selectors->first;
				goto try_next_list;
			}
		}

		return NULL;
	}

	if (entry->prev == NULL) {
		next = lexbor_dobject_calloc(selectors->objs);

		next->combinator = selector->combinator;
		next->selector = selector->prev;
		next->node = node;

		next->next = entry;
		entry->prev = next;

		return next;
	}

	entry->prev->node = node;

	return entry->prev;
}

static lxb_selectors_entry_t *
lxb_selectors_state_pseudo_class_function(lxb_selectors_t *selectors,
										  lxb_selectors_entry_t *entry)
{
	const xmlNode *node, *base;
	lxb_selectors_nested_t *current;
	const lxb_css_selector_list_t *list;
	lxb_css_selector_anb_of_t *anb;
	const lxb_css_selector_pseudo_t *pseudo;

	current = selectors->current;

	base = lxb_selectors_next_node(current);
	if (base == NULL) {
		goto not_found;
	}

	pseudo = &current->parent->last->selector->u.pseudo;

	switch (pseudo->type) {
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_HAS:
			list = (lxb_css_selector_list_t *) pseudo->data;
			node = lxb_selectors_state_has_relative(base, list->first);

			if (node == NULL) {
				selectors->current = selectors->current->parent;
				entry = selectors->current->last;

				selectors->state = lxb_selectors_state_find;

				return lxb_selectors_state_find_check(selectors, NULL,
													  entry->selector, entry);
			}

			current->root = base;

			current->entry->selector = list->last;
			current->entry->node = node;
			current->return_state = lxb_selectors_state_after_find_has;
			current->cb = lxb_selectors_cb_ok;
			current->ctx = &current->found;
			current->found = false;

			selectors->state = lxb_selectors_state_find;

			return entry;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_CURRENT:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_IS:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_WHERE:
			current->entry->selector = ((lxb_css_selector_list_t *) pseudo->data)->last;
			current->entry->node = base;
			current->return_state = lxb_selectors_state_after_find;
			current->cb = lxb_selectors_cb_ok;
			current->ctx = &current->found;
			current->found = false;

			selectors->state = lxb_selectors_state_find;

			return entry;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NOT:
			current->entry->selector = ((lxb_css_selector_list_t *) pseudo->data)->last;
			current->entry->node = base;
			current->return_state = lxb_selectors_state_after_find;
			current->cb = lxb_selectors_cb_not;
			current->ctx = &current->found;
			current->found = true;

			selectors->state = lxb_selectors_state_find;

			return entry;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_CHILD:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_CHILD:
			anb = pseudo->data;

			current->entry->selector = anb->of->last;
			current->entry->node = base;
			current->return_state = lxb_selectors_state_after_nth_child;
			current->cb = lxb_selectors_cb_ok;
			current->ctx = &current->found;
			current->root = base;
			current->index = 0;
			current->found = false;

			selectors->state = lxb_selectors_state_find;

			return entry;

		/*
		 * This one can only happen if the user has somehow messed up the
		 * selector.
		 */

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_OF_TYPE:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_OF_TYPE:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_DIR:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_LANG:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_COL:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_COL:
		default:
			break;
	}

not_found:

	selectors->current = selectors->current->parent;
	entry = selectors->current->last;

	selectors->state = lxb_selectors_state_find;

	return lxb_selectors_state_find_check(selectors, NULL,
										  entry->selector, entry);
}

static const xmlNode *
lxb_selectors_next_node(lxb_selectors_nested_t *main)
{
	const xmlNode *node = main->entry->node;

	switch (main->parent->last->combinator) {
		case LXB_CSS_SELECTOR_COMBINATOR_DESCENDANT:
		case LXB_CSS_SELECTOR_COMBINATOR_CHILD:
			if (node->parent == NULL
				|| !CMP_NODE_TYPE(node->parent, XML_ELEMENT_NODE))
			{
				return NULL;
			}

			return node->parent;

		case LXB_CSS_SELECTOR_COMBINATOR_CLOSE:
			return node;

		case LXB_CSS_SELECTOR_COMBINATOR_SIBLING:
		case LXB_CSS_SELECTOR_COMBINATOR_FOLLOWING:
			node = node->prev;
			break;

		default:
			return NULL;
	}

	while (node != NULL) {
		if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
			break;
		}

		node = node->prev;
	}

	return node;
}

static const xmlNode *
lxb_selectors_state_has_relative(const xmlNode *node,
								 const lxb_css_selector_t *selector)
{
	const xmlNode *root = node;

	switch (selector->combinator) {
		case LXB_CSS_SELECTOR_COMBINATOR_DESCENDANT:
		case LXB_CSS_SELECTOR_COMBINATOR_CHILD:
			node = node->children;
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_SIBLING:
		case LXB_CSS_SELECTOR_COMBINATOR_FOLLOWING:
			node = node->next;
			break;

		default:
			return NULL;
	}

	while (node != NULL) {
		if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
			break;
		}

		while (node !=root && node->next == NULL) {
			node = node->parent;
		}

		if (node == root) {
			return NULL;
		}

		node = node->next;
	}

	return node;
}

static lxb_selectors_entry_t *
lxb_selectors_state_after_find_has(lxb_selectors_t *selectors,
								   lxb_selectors_entry_t *entry)
{
	const xmlNode *node;
	lxb_selectors_entry_t *parent;
	lxb_selectors_nested_t *current;

	if (selectors->current->found) {
		node = selectors->current->root;

		selectors->current = selectors->current->parent;
		parent = selectors->current->last;

		selectors->state = lxb_selectors_state_find;

		return lxb_selectors_state_find_check(selectors, node,
											  parent->selector, parent);
	}

	current = selectors->current;
	node = entry->node;

	switch (entry->selector->list->first->combinator) {
		case LXB_CSS_SELECTOR_COMBINATOR_DESCENDANT:
			if (node->children != NULL) {
				node = node->children;
			}
			else {

			next:

				while (node != current->root && node->next == NULL) {
					node = node->parent;
				}

				if (node == current->root) {
					goto failed;
				}

				node = node->next;
			}

			if (!CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
				goto next;
			}

			break;

		case LXB_CSS_SELECTOR_COMBINATOR_CHILD:
		case LXB_CSS_SELECTOR_COMBINATOR_FOLLOWING:
			node = node->next;

			while (node != NULL && !CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
				node = node->next;
			}

			if (node == NULL) {
				goto failed;
			}

			break;

		case LXB_CSS_SELECTOR_COMBINATOR_SIBLING:
			goto failed;

		case LXB_CSS_SELECTOR_COMBINATOR_CLOSE:
		case LXB_CSS_SELECTOR_COMBINATOR_CELL:
		default:
			selectors->status = LXB_STATUS_ERROR;
			return NULL;
	}

	entry->node = node;
	selectors->state = lxb_selectors_state_find;

	return entry;

failed:

	selectors->current = selectors->current->parent;
	parent = selectors->current->last;

	selectors->state = lxb_selectors_state_find;

	return lxb_selectors_state_find_check(selectors, NULL,
										  parent->selector, parent);
}


static lxb_selectors_entry_t *
lxb_selectors_state_after_find(lxb_selectors_t *selectors,
							   lxb_selectors_entry_t *entry)
{
	const xmlNode *node;
	lxb_selectors_entry_t *parent;
	lxb_selectors_nested_t *current;

	current = selectors->current;

	if (current->found) {
		node = entry->node;

		selectors->current = current->parent;
		parent = selectors->current->last;

		selectors->state = lxb_selectors_state_find;

		return lxb_selectors_state_find_check(selectors, node,
											  parent->selector, parent);
	}

	node = entry->node;

	switch (current->parent->last->combinator) {
		case LXB_CSS_SELECTOR_COMBINATOR_DESCENDANT:
			if (node->parent != NULL
				&& CMP_NODE_TYPE(node->parent, XML_ELEMENT_NODE))
			{
				node = node->parent;
			}
			else {
				node = NULL;
			}

			break;

		case LXB_CSS_SELECTOR_COMBINATOR_FOLLOWING:
			node = node->prev;

			while (node != NULL && !CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
				node = node->prev;
			}

			break;

		case LXB_CSS_SELECTOR_COMBINATOR_CHILD:
		case LXB_CSS_SELECTOR_COMBINATOR_SIBLING:
		case LXB_CSS_SELECTOR_COMBINATOR_CLOSE:
			node = NULL;
			break;

		case LXB_CSS_SELECTOR_COMBINATOR_CELL:
		default:
			selectors->status = LXB_STATUS_ERROR;
			return NULL;
	}

	if (node == NULL) {
		selectors->current = current->parent;
		parent = selectors->current->last;

		selectors->state = lxb_selectors_state_find;

		return lxb_selectors_state_find_check(selectors, node,
											  parent->selector, parent);
	}

	entry->node = node;
	selectors->state = lxb_selectors_state_find;

	return entry;
}

static lxb_selectors_entry_t *
lxb_selectors_state_after_nth_child(lxb_selectors_t *selectors,
									lxb_selectors_entry_t *entry)
{
	bool found;
	const xmlNode *node;
	lxb_selectors_entry_t *parent;
	lxb_selectors_nested_t *current;
	const lxb_css_selector_t *selector;
	const lxb_css_selector_pseudo_t *pseudo;

	current = selectors->current;
	selector = current->parent->last->selector;
	pseudo = &selector->u.pseudo;

	node = entry->node;

	if (current->found) {
		current->index += 1;
	}
	else if (current->root == node) {
		node = NULL;
		goto done;
	}

	if (pseudo->type == LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_CHILD) {
		node = node->prev;

		while (node != NULL) {
			if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
				break;
			}

			node = node->prev;
		}
	}
	else {
		node = node->next;

		while (node != NULL) {
			if (CMP_NODE_TYPE(node, XML_ELEMENT_NODE)) {
				break;
			}

			node = node->next;
		}
	}

	if (node == NULL) {
		goto done;
	}

	entry->node = node;
	current->found = false;
	selectors->state = lxb_selectors_state_find;

	return entry;

done:

	if (current->index > 0) {
		found = lxb_selectors_anb_calc(pseudo->data, current->index);

		node = (found) ? current->root : NULL;
	}

	selectors->state = lxb_selectors_state_find;
	selectors->current = selectors->current->parent;

	parent = selectors->current->last;

	return lxb_selectors_state_find_check(selectors, node,
										  parent->selector, parent);
}

static bool
lxb_selectors_match(lxb_selectors_t *selectors, lxb_selectors_entry_t *entry,
					const lxb_css_selector_t *selector, const xmlNode *node)
{
	switch (selector->type) {
		case LXB_CSS_SELECTOR_TYPE_ANY:
			return true;

		case LXB_CSS_SELECTOR_TYPE_ELEMENT:
			return lxb_selectors_match_element(selector, node, entry);

		case LXB_CSS_SELECTOR_TYPE_ID:
			return lxb_selectors_match_id(selector, node, selectors->options & LXB_SELECTORS_OPT_QUIRKS_MODE);

		case LXB_CSS_SELECTOR_TYPE_CLASS: {
			const xmlAttr *dom_attr = lxb_selectors_adapted_attr(node, (const lxb_char_t *) "class");
			if (dom_attr == NULL) {
				return false;
			}

			dom_lxb_str_wrapper trg = lxb_selectors_adapted_attr_value(dom_attr);

			if (trg.str.length == 0) {
				dom_lxb_str_wrapper_release(&trg);
				return false;
			}

			bool ret = lxb_selectors_match_class(&trg.str,
												 &selector->name, selectors->options & LXB_SELECTORS_OPT_QUIRKS_MODE);
			dom_lxb_str_wrapper_release(&trg);
			return ret;
		}

		case LXB_CSS_SELECTOR_TYPE_ATTRIBUTE:
			return lxb_selectors_match_attribute(selector, node, entry);

		case LXB_CSS_SELECTOR_TYPE_PSEUDO_CLASS:
			return lxb_selectors_pseudo_class(selector, node);

		case LXB_CSS_SELECTOR_TYPE_PSEUDO_CLASS_FUNCTION:
			return lxb_selectors_pseudo_class_function(selector, node);

		case LXB_CSS_SELECTOR_TYPE_PSEUDO_ELEMENT:
			return lxb_selectors_pseudo_element(selector, node);

		case LXB_CSS_SELECTOR_TYPE_PSEUDO_ELEMENT_FUNCTION:
			return false;

		EMPTY_SWITCH_DEFAULT_CASE();
	}

	return false;
}

static bool
lxb_selectors_match_element(const lxb_css_selector_t *selector,
							const xmlNode *node, lxb_selectors_entry_t *entry)
{
	lxb_selectors_adapted_set_entry_id(entry, selector, node);
	return lxb_selectors_adapted_cmp_local_name_id(node, &entry->id);
}

static bool
lxb_selectors_match_id(const lxb_css_selector_t *selector, const xmlNode *node, bool quirks)
{
	const xmlAttr *dom_attr = lxb_selectors_adapted_attr(node, (const lxb_char_t *) "id");
	if (dom_attr == NULL) {
		return false;
	}

	const lexbor_str_t *src = &selector->name;
	dom_lxb_str_wrapper trg = lxb_selectors_adapted_attr_value(dom_attr);
	bool ret = false;
	if (trg.str.length == src->length) {
		if (quirks) {
			ret = lexbor_str_data_ncasecmp(trg.str.data, src->data, src->length);
		} else {
			ret = lexbor_str_data_ncmp(trg.str.data, src->data, src->length);
		}
	}
	dom_lxb_str_wrapper_release(&trg);

	return ret;
}

static bool
lxb_selectors_match_class(const lexbor_str_t *target, const lexbor_str_t *src,
						  bool quirks)
{
	lxb_char_t chr;

	if (target->length < src->length) {
		return false;
	}

	bool is_it = false;

	const lxb_char_t *data = target->data;
	const lxb_char_t *pos = data;
	const lxb_char_t *end = data + target->length;

	for (; data < end; data++) {
		chr = *data;

		if (lexbor_utils_whitespace(chr, ==, ||)) {

			if ((size_t) (data - pos) == src->length) {
				if (quirks) {
					is_it = lexbor_str_data_ncasecmp(pos, src->data, src->length);
				}
				else {
					is_it = lexbor_str_data_ncmp(pos, src->data, src->length);
				}

				if (is_it) {
					return true;
				}
			}

			if ((size_t) (end - data) < src->length) {
				return false;
			}

			pos = data + 1;
		}
	}

	if ((size_t) (end - pos) == src->length && src->length != 0) {
		if (quirks) {
			is_it = lexbor_str_data_ncasecmp(pos, src->data, src->length);
		}
		else {
			is_it = lexbor_str_data_ncmp(pos, src->data, src->length);
		}
	}

	return is_it;
}

static bool
lxb_selectors_match_attribute_value(const lxb_css_selector_attribute_t *attr, const lexbor_str_t *trg, const lexbor_str_t *src)
{
	bool res;
	bool ins = attr->modifier == LXB_CSS_SELECTOR_MODIFIER_I;

	switch (attr->match) {
		case LXB_CSS_SELECTOR_MATCH_EQUAL:      /*  = */
			if (trg->length == src->length) {
				if (ins) {
					return lexbor_str_data_ncasecmp(trg->data, src->data,
													src->length);
				}

				return lexbor_str_data_ncmp(trg->data, src->data,
											src->length);
			}

			return false;

		case LXB_CSS_SELECTOR_MATCH_INCLUDE:    /* ~= */
			return lxb_selectors_match_class(trg, src, ins);

		case LXB_CSS_SELECTOR_MATCH_DASH:       /* |= */
			if (trg->length == src->length) {
				if (ins) {
					return lexbor_str_data_ncasecmp(trg->data, src->data,
													src->length);
				}

				return lexbor_str_data_ncmp(trg->data, src->data,
											src->length);
			}

			if (trg->length > src->length) {
				if (ins) {
					res = lexbor_str_data_ncasecmp(trg->data,
												   src->data, src->length);
				}
				else {
					res = lexbor_str_data_ncmp(trg->data,
											   src->data, src->length);
				}

				if (res && trg->data[src->length] == '-') {
					return true;
				}
			}

			return false;

		case LXB_CSS_SELECTOR_MATCH_PREFIX:     /* ^= */
			if (src->length != 0 && trg->length >= src->length) {
				if (ins) {
					return lexbor_str_data_ncasecmp(trg->data, src->data,
													src->length);
				}

				return lexbor_str_data_ncmp(trg->data, src->data,
											src->length);
			}

			return false;

		case LXB_CSS_SELECTOR_MATCH_SUFFIX:     /* $= */
			if (src->length != 0 && trg->length >= src->length) {
				size_t dif = trg->length - src->length;

				if (ins) {
					return lexbor_str_data_ncasecmp(trg->data + dif,
													src->data, src->length);
				}

				return lexbor_str_data_ncmp(trg->data + dif, src->data,
											src->length);
			}

			return false;

		case LXB_CSS_SELECTOR_MATCH_SUBSTRING:  /* *= */
			if (src->length == 0) {
				return false;
			}

			if (ins) {
				return lexbor_str_data_ncasecmp_contain(trg->data, trg->length,
														src->data, src->length);
			}

			return lexbor_str_data_ncmp_contain(trg->data, trg->length,
												src->data, src->length);
		EMPTY_SWITCH_DEFAULT_CASE();
	}

	return false;
}

static bool
lxb_selectors_match_attribute(const lxb_css_selector_t *selector,
							  const xmlNode *node, lxb_selectors_entry_t *entry)
{
	const lxb_css_selector_attribute_t *attr = &selector->u.attribute;

	lxb_selectors_adapted_set_entry_id(entry, selector, node);

	const xmlAttr *dom_attr = lxb_selectors_adapted_attr(node, entry->id.name);
	if (dom_attr == NULL) {
		return false;
	}

	const lexbor_str_t *src = &attr->value;
	if (src->data == NULL) {
		return true;
	}

	dom_lxb_str_wrapper trg = lxb_selectors_adapted_attr_value(dom_attr);
	bool res = lxb_selectors_match_attribute_value(attr, &trg.str, src);
	dom_lxb_str_wrapper_release(&trg);
	return res;
}

static bool
lxb_selectors_pseudo_class(const lxb_css_selector_t *selector,
						   const xmlNode *node)
{
	const lxb_css_selector_pseudo_t *pseudo = &selector->u.pseudo;

	static const lxb_char_t checkbox[] = "checkbox";
	static const size_t checkbox_length = sizeof(checkbox) / sizeof(lxb_char_t) - 1;

	static const lxb_char_t radio[] = "radio";
	static const size_t radio_length = sizeof(radio) / sizeof(lxb_char_t) - 1;

	switch (pseudo->type) {
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_ACTIVE:
			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_ANY_LINK:
			/* https://drafts.csswg.org/selectors/#the-any-link-pseudo */
			if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)
				&& (lxb_selectors_adapted_cmp_local_name_literal(node, "a")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "area")))
			{
				return lxb_selectors_adapted_has_attr(node, "href");
			}

			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_BLANK:
			if (!EG(exception)) {
				php_dom_throw_error_with_message(NOT_SUPPORTED_ERR, ":blank selector is not implemented because CSSWG has not yet decided its semantics (https://github.com/w3c/csswg-drafts/issues/1967)", true);
			}
			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_CHECKED:
			/* https://drafts.csswg.org/selectors/#checked */
			if (!php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)) {
				return false;
			}
			if (lxb_selectors_adapted_cmp_local_name_literal(node, "input")) {
				const xmlAttr *dom_attr = lxb_selectors_adapted_attr(node, (const lxb_char_t *) "type");
				if (dom_attr == NULL) {
					return false;
				}

				dom_lxb_str_wrapper str = lxb_selectors_adapted_attr_value(dom_attr);
				bool res = false;

				if (str.str.length == 8) {
					if (lexbor_str_data_ncasecmp(checkbox, str.str.data, checkbox_length)) {
						res = lxb_selectors_adapted_has_attr(node, "checked");
					}
				}
				else if (str.str.length == 5) {
					if (lexbor_str_data_ncasecmp(radio, str.str.data, radio_length)) {
						res = lxb_selectors_adapted_has_attr(node, "checked");
					}
				}

				dom_lxb_str_wrapper_release(&str);

				return res;
			}
			else if(lxb_selectors_adapted_cmp_local_name_literal(node, "option")) {
				return lxb_selectors_adapted_has_attr(node, "selected");
			}

			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_CURRENT:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_DEFAULT:
			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_DISABLED:
			return lxb_selectors_pseudo_class_disabled(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_EMPTY:
			node = node->children;

			while (node != NULL) {
				/* Following https://developer.mozilla.org/en-US/docs/Web/CSS/:empty, i.e. what currently happens in browsers,
				 * not the CSS Selectors Level 4 Draft that no one implements yet. */
				if (!CMP_NODE_TYPE(node, XML_COMMENT_NODE) && !CMP_NODE_TYPE(node, XML_PI_NODE)) {
					return false;
				}

				node = node->next;
			}

			return true;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_ENABLED:
			return !lxb_selectors_pseudo_class_disabled(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FIRST_CHILD:
			return lxb_selectors_pseudo_class_first_child(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FIRST_OF_TYPE:
			return lxb_selectors_pseudo_class_first_of_type(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FOCUS:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FOCUS_VISIBLE:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FOCUS_WITHIN:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FULLSCREEN:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUTURE:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_HOVER:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_IN_RANGE:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_INDETERMINATE:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_INVALID:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_LAST_CHILD:
			return lxb_selectors_pseudo_class_last_child(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_LAST_OF_TYPE:
			return lxb_selectors_pseudo_class_last_of_type(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_LINK:
			/* https://html.spec.whatwg.org/multipage/semantics-other.html#selector-link */
			if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)
				&& (lxb_selectors_adapted_cmp_local_name_literal(node, "a")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "area")))
			{
				return lxb_selectors_adapted_has_attr(node, "href");
			}

			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_LOCAL_LINK:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_ONLY_CHILD:
			return lxb_selectors_pseudo_class_first_child(node)
				&& lxb_selectors_pseudo_class_last_child(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_ONLY_OF_TYPE:
			return lxb_selectors_pseudo_class_first_of_type(node)
				&& lxb_selectors_pseudo_class_last_of_type(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_OPTIONAL:
			if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)
				&& (lxb_selectors_adapted_cmp_local_name_literal(node, "input")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "select")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "textarea")))
			{
				return !lxb_selectors_adapted_has_attr(node, "required");
			}

			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_OUT_OF_RANGE:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_PAST:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_PLACEHOLDER_SHOWN:
			if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)
				&& (lxb_selectors_adapted_cmp_local_name_literal(node, "input")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "textarea")))
			{
				return lxb_selectors_adapted_has_attr(node, "placeholder");
			}

			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_READ_ONLY:
			return !lxb_selectors_pseudo_class_read_write(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_READ_WRITE:
			return lxb_selectors_pseudo_class_read_write(node);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_REQUIRED:
			if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)
				&& (lxb_selectors_adapted_cmp_local_name_literal(node, "input")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "select")
					|| lxb_selectors_adapted_cmp_local_name_literal(node, "textarea")))
			{
				return lxb_selectors_adapted_has_attr(node, "required");
			}

			return false;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_ROOT:
			return node->parent != NULL
				&& (node->parent->type == XML_DOCUMENT_FRAG_NODE || node->parent->type == XML_DOCUMENT_NODE
					|| node->parent->type == XML_HTML_DOCUMENT_NODE);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_SCOPE:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_TARGET:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_TARGET_WITHIN:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_USER_INVALID:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_VALID:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_VISITED:
			break;

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_WARNING:
			break;
	}

	return false;
}

static bool
lxb_selectors_pseudo_class_function(const lxb_css_selector_t *selector,
									const xmlNode *node)
{
	size_t index;
	const xmlNode *base;
	const lxb_css_selector_pseudo_t *pseudo;

	pseudo = &selector->u.pseudo;

	switch (pseudo->type) {
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_CHILD:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_CHILD:
			index = 0;

			if (pseudo->type == LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_CHILD) {
				while (node != NULL) {
					if (lxb_selectors_adapted_is_matchable_child(node))
					{
						index++;
					}

					node = node->prev;
				}
			}
			else {
				while (node != NULL) {
					if (lxb_selectors_adapted_is_matchable_child(node))
					{
						index++;
					}

					node = node->next;
				}
			}

			return lxb_selectors_anb_calc(pseudo->data, index);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_OF_TYPE:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_OF_TYPE:
			index = 0;
			base = node;

			if (pseudo->type == LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_OF_TYPE) {
				while (node != NULL) {
					if(lxb_selectors_adapted_is_matchable_child(node)
						&& xmlStrEqual(node->name, base->name)
						&& lxb_selectors_adapted_cmp_ns(node, base))
					{
						index++;
					}

					node = node->prev;
				}
			}
			else {
				while (node != NULL) {
					if(lxb_selectors_adapted_is_matchable_child(node)
						&& xmlStrEqual(node->name, base->name)
						&& lxb_selectors_adapted_cmp_ns(node, base))
					{
						index++;
					}

					node = node->next;
				}
			}

			return lxb_selectors_anb_calc(pseudo->data, index);

		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_DIR:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_LANG:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_COL:
		case LXB_CSS_SELECTOR_PSEUDO_CLASS_FUNCTION_NTH_LAST_COL:
		default:
			break;
	}

	return false;
}

static bool
lxb_selectors_pseudo_element(const lxb_css_selector_t *selector,
							 const xmlNode *node)
{
	const lxb_css_selector_pseudo_t *pseudo = &selector->u.pseudo;

	switch (pseudo->type) {
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_AFTER:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_BACKDROP:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_BEFORE:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_FIRST_LETTER:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_FIRST_LINE:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_GRAMMAR_ERROR:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_INACTIVE_SELECTION:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_MARKER:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_PLACEHOLDER:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_SELECTION:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_SPELLING_ERROR:
		case LXB_CSS_SELECTOR_PSEUDO_ELEMENT_TARGET_TEXT:
			break;
	}

	return false;
}

/* https://html.spec.whatwg.org/multipage/semantics-other.html#concept-element-disabled */
static bool
lxb_selectors_pseudo_class_disabled(const xmlNode *node)
{
	if (!php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)) {
		return false;
	}

	if (lxb_selectors_adapted_has_attr(node, "disabled")
		&& (lxb_selectors_adapted_cmp_local_name_literal(node, "button")
			|| lxb_selectors_adapted_cmp_local_name_literal(node, "input")
			|| lxb_selectors_adapted_cmp_local_name_literal(node, "select")
			|| lxb_selectors_adapted_cmp_local_name_literal(node, "textarea")
			|| lxb_selectors_adapted_cmp_local_name_literal(node, "optgroup")
			|| lxb_selectors_adapted_cmp_local_name_literal(node, "fieldset")))
	{
		return true;
	}

	if (lxb_selectors_adapted_cmp_local_name_literal(node, "fieldset")) {
		const xmlNode *fieldset = node;
		node = node->parent;

		while (node != NULL && lxb_selectors_adapted_is_matchable_child(node)) {
			/* node is a disabled fieldset that is an ancestor of fieldset */
			if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)
				&& lxb_selectors_adapted_cmp_local_name_literal(node, "fieldset")
				&& lxb_selectors_adapted_has_attr(node, "disabled"))
			{
				/* Search first legend child and figure out if fieldset is a descendent from that. */
				const xmlNode *search_current = node->children;
				do {
					if (search_current->type == XML_ELEMENT_NODE
						&& php_dom_ns_is_fast(search_current, php_dom_ns_is_html_magic_token)
						&& lxb_selectors_adapted_cmp_local_name_literal(search_current, "legend")) {
						/* search_current is a legend element. */
						const xmlNode *inner_search_current = fieldset;

						/* Disabled does not apply if fieldset is a descendant from search_current */
						do {
							if (inner_search_current == search_current) {
								return false;
							}

							inner_search_current = inner_search_current->parent;
						} while (inner_search_current != NULL);

						return true;
					}

					search_current = search_current->next;
				} while (search_current != NULL);
			}

			node = node->parent;
		}
	}

	return false;
}

static bool
lxb_selectors_pseudo_class_first_child(const xmlNode *node)
{
	node = node->prev;

	while (node != NULL) {
		if (lxb_selectors_adapted_is_matchable_child(node))
		{
			return false;
		}

		node = node->prev;
	}

	return true;
}

static bool
lxb_selectors_pseudo_class_first_of_type(const xmlNode *node)
{
	const xmlNode *root = node;
	node = node->prev;

	while (node) {
		if (lxb_selectors_adapted_is_matchable_child(node)
			&& xmlStrEqual(node->name, root->name)
			&& lxb_selectors_adapted_cmp_ns(node, root))
		{
			return false;
		}

		node = node->prev;
	}

	return true;
}

static bool
lxb_selectors_pseudo_class_last_child(const xmlNode *node)
{
	node = node->next;

	while (node != NULL) {
		if (lxb_selectors_adapted_is_matchable_child(node))
		{
			return false;
		}

		node = node->next;
	}

	return true;
}

static bool
lxb_selectors_pseudo_class_last_of_type(const xmlNode *node)
{
	const xmlNode *root = node;
	node = node->next;

	while (node) {
		if (lxb_selectors_adapted_is_matchable_child(node)
			&& xmlStrEqual(node->name, root->name)
			&& lxb_selectors_adapted_cmp_ns(node, root))
		{
			return false;
		}

		node = node->next;
	}

	return true;
}

/* https://drafts.csswg.org/selectors/#rw-pseudos */
static bool
lxb_selectors_pseudo_class_read_write(const xmlNode *node)
{
	if (php_dom_ns_is_fast(node, php_dom_ns_is_html_magic_token)) {
		if (lxb_selectors_adapted_cmp_local_name_literal(node, "input")
			|| lxb_selectors_adapted_cmp_local_name_literal(node, "textarea")) {
			return !lxb_selectors_adapted_has_attr(node, "readonly") && !lxb_selectors_adapted_has_attr(node, "disabled");
		} else {
			const xmlAttr *attr = lxb_selectors_adapted_attr(node, (const lxb_char_t *) "contenteditable");
			return attr && !dom_compare_value(attr, BAD_CAST "false");
		}
	}

	return false;
}

static bool
lxb_selectors_anb_calc(const lxb_css_selector_anb_of_t *anb, size_t index)
{
	double num;

	if (anb->anb.a == 0) {
		if (anb->anb.b >= 0 && (size_t) anb->anb.b == index) {
			return true;
		}
	}
	else {
		num = ((double) index - (double) anb->anb.b) / (double) anb->anb.a;

		if (num >= 0.0f && (num - trunc(num)) == 0.0f) {
			return true;
		}
	}

	return false;
}

static lxb_status_t
lxb_selectors_cb_ok(const xmlNode *node,
					lxb_css_selector_specificity_t spec, void *ctx)
{
	*((bool *) ctx) = true;
	return LXB_STATUS_OK;
}

static lxb_status_t
lxb_selectors_cb_not(const xmlNode *node,
					 lxb_css_selector_specificity_t spec, void *ctx)
{
	*((bool *) ctx) = false;
	return LXB_STATUS_OK;
}