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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <LibHTML/CSS/SelectorEngine.h>
28#include <LibHTML/DOM/Document.h>
29#include <LibHTML/DOM/Element.h>
30#include <LibHTML/DOM/Text.h>
31
32namespace SelectorEngine {
33
34static bool matches_hover_pseudo_class(const Element& element)
35{
36 auto* hovered_node = element.document().hovered_node();
37 if (!hovered_node)
38 return false;
39 if (&element == hovered_node)
40 return true;
41 return element.is_ancestor_of(*hovered_node);
42}
43
44bool matches(const Selector::SimpleSelector& component, const Element& element)
45{
46 switch (component.pseudo_class) {
47 case Selector::SimpleSelector::PseudoClass::None:
48 break;
49 case Selector::SimpleSelector::PseudoClass::Link:
50 if (!element.is_link())
51 return false;
52 break;
53 case Selector::SimpleSelector::PseudoClass::Hover:
54 if (!matches_hover_pseudo_class(element))
55 return false;
56 break;
57 case Selector::SimpleSelector::PseudoClass::FirstChild:
58 if (element.previous_element_sibling())
59 return false;
60 break;
61 case Selector::SimpleSelector::PseudoClass::LastChild:
62 if (element.next_element_sibling())
63 return false;
64 break;
65 case Selector::SimpleSelector::PseudoClass::OnlyChild:
66 if (element.previous_element_sibling() || element.next_element_sibling())
67 return false;
68 break;
69 case Selector::SimpleSelector::PseudoClass::Empty:
70 if (element.first_child_of_type<Element>() || element.first_child_of_type<Text>())
71 return false;
72 break;
73 }
74
75 switch (component.attribute_match_type) {
76 case Selector::SimpleSelector::AttributeMatchType::HasAttribute:
77 if (!element.has_attribute(component.attribute_name))
78 return false;
79 break;
80 case Selector::SimpleSelector::AttributeMatchType::ExactValueMatch:
81 if (element.attribute(component.attribute_name) != component.attribute_value)
82 return false;
83 break;
84 default:
85 break;
86 }
87
88 switch (component.type) {
89 case Selector::SimpleSelector::Type::Universal:
90 return true;
91 case Selector::SimpleSelector::Type::Id:
92 return component.value == element.attribute("id");
93 case Selector::SimpleSelector::Type::Class:
94 return element.has_class(component.value);
95 case Selector::SimpleSelector::Type::TagName:
96 return component.value == element.tag_name();
97 default:
98 ASSERT_NOT_REACHED();
99 }
100}
101
102bool matches(const Selector& selector, int component_list_index, const Element& element)
103{
104 auto& component_list = selector.complex_selectors()[component_list_index];
105 for (auto& component : component_list.compound_selector) {
106 if (!matches(component, element))
107 return false;
108 }
109 switch (component_list.relation) {
110 case Selector::ComplexSelector::Relation::None:
111 return true;
112 case Selector::ComplexSelector::Relation::Descendant:
113 ASSERT(component_list_index != 0);
114 for (auto* ancestor = element.parent(); ancestor; ancestor = ancestor->parent()) {
115 if (!is<Element>(*ancestor))
116 continue;
117 if (matches(selector, component_list_index - 1, to<Element>(*ancestor)))
118 return true;
119 }
120 return false;
121 case Selector::ComplexSelector::Relation::ImmediateChild:
122 ASSERT(component_list_index != 0);
123 if (!element.parent() || !is<Element>(*element.parent()))
124 return false;
125 return matches(selector, component_list_index - 1, to<Element>(*element.parent()));
126 case Selector::ComplexSelector::Relation::AdjacentSibling:
127 ASSERT(component_list_index != 0);
128 if (auto* sibling = element.previous_element_sibling())
129 return matches(selector, component_list_index - 1, *sibling);
130 return false;
131 case Selector::ComplexSelector::Relation::GeneralSibling:
132 ASSERT(component_list_index != 0);
133 for (auto* sibling = element.previous_element_sibling(); sibling; sibling = sibling->previous_element_sibling()) {
134 if (matches(selector, component_list_index - 1, *sibling))
135 return true;
136 }
137 return false;
138 }
139 ASSERT_NOT_REACHED();
140}
141
142bool matches(const Selector& selector, const Element& element)
143{
144 ASSERT(!selector.complex_selectors().is_empty());
145 return matches(selector, selector.complex_selectors().size() - 1, element);
146}
147
148}