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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/StyleResolver.h>
28#include <LibHTML/CSS/PropertyID.h>
29#include <LibHTML/CSS/Length.h>
30#include <LibHTML/DOM/Document.h>
31#include <LibHTML/DOM/Element.h>
32#include <LibHTML/Layout/LayoutBlock.h>
33#include <LibHTML/Layout/LayoutInline.h>
34#include <LibHTML/Layout/LayoutListItem.h>
35#include <LibHTML/Layout/LayoutTable.h>
36#include <LibHTML/Layout/LayoutTableCell.h>
37#include <LibHTML/Layout/LayoutTableRow.h>
38#include <LibHTML/Layout/LayoutTreeBuilder.h>
39
40Element::Element(Document& document, const String& tag_name)
41 : ParentNode(document, NodeType::ELEMENT_NODE)
42 , m_tag_name(tag_name)
43{
44}
45
46Element::~Element()
47{
48}
49
50Attribute* Element::find_attribute(const String& name)
51{
52 for (auto& attribute : m_attributes) {
53 if (attribute.name() == name)
54 return &attribute;
55 }
56 return nullptr;
57}
58
59const Attribute* Element::find_attribute(const String& name) const
60{
61 for (auto& attribute : m_attributes) {
62 if (attribute.name() == name)
63 return &attribute;
64 }
65 return nullptr;
66}
67
68String Element::attribute(const String& name) const
69{
70 if (auto* attribute = find_attribute(name))
71 return attribute->value();
72 return {};
73}
74
75void Element::set_attribute(const String& name, const String& value)
76{
77 if (auto* attribute = find_attribute(name))
78 attribute->set_value(value);
79 else
80 m_attributes.empend(name, value);
81
82 parse_attribute(name, value);
83}
84
85void Element::set_attributes(Vector<Attribute>&& attributes)
86{
87 m_attributes = move(attributes);
88
89 for (auto& attribute : m_attributes)
90 parse_attribute(attribute.name(), attribute.value());
91}
92
93bool Element::has_class(const StringView& class_name) const
94{
95 auto value = attribute("class");
96 if (value.is_empty())
97 return false;
98 auto parts = value.split_view(' ');
99 for (auto& part : parts) {
100 if (part == class_name)
101 return true;
102 }
103 return false;
104}
105
106RefPtr<LayoutNode> Element::create_layout_node(const StyleProperties* parent_style) const
107{
108 auto style = document().style_resolver().resolve_style(*this, parent_style);
109 const_cast<Element&>(*this).m_resolved_style = style;
110 auto display = style->string_or_fallback(CSS::PropertyID::Display, "inline");
111
112 if (display == "none")
113 return nullptr;
114 if (display == "block")
115 return adopt(*new LayoutBlock(this, move(style)));
116 if (display == "inline")
117 return adopt(*new LayoutInline(*this, move(style)));
118 if (display == "list-item")
119 return adopt(*new LayoutListItem(*this, move(style)));
120 if (display == "table")
121 return adopt(*new LayoutTable(*this, move(style)));
122 if (display == "table-row")
123 return adopt(*new LayoutTableRow(*this, move(style)));
124 if (display == "table-cell")
125 return adopt(*new LayoutTableCell(*this, move(style)));
126 if (display == "inline-block")
127 return adopt(*new LayoutBlock(this, move(style)));
128
129 ASSERT_NOT_REACHED();
130}
131
132void Element::parse_attribute(const String&, const String&)
133{
134}
135
136enum class StyleDifference {
137 None,
138 NeedsRepaint,
139 NeedsRelayout,
140};
141
142static StyleDifference compute_style_difference(const StyleProperties& old_style, const StyleProperties& new_style, const Document& document)
143{
144 if (old_style == new_style)
145 return StyleDifference::None;
146
147 bool needs_repaint = false;
148 bool needs_relayout = false;
149
150 if (new_style.color_or_fallback(CSS::PropertyID::Color, document, Color::Black) != old_style.color_or_fallback(CSS::PropertyID::Color, document, Color::Black))
151 needs_repaint = true;
152 else if (new_style.color_or_fallback(CSS::PropertyID::BackgroundColor, document, Color::Black) != old_style.color_or_fallback(CSS::PropertyID::BackgroundColor, document, Color::Black))
153 needs_repaint = true;
154
155 if (needs_relayout)
156 return StyleDifference::NeedsRelayout;
157 if (needs_repaint)
158 return StyleDifference::NeedsRepaint;
159 return StyleDifference::None;
160}
161
162void Element::recompute_style()
163{
164 set_needs_style_update(false);
165 ASSERT(parent());
166 auto* parent_layout_node = parent()->layout_node();
167 if (!parent_layout_node)
168 return;
169 ASSERT(parent_layout_node);
170 auto style = document().style_resolver().resolve_style(*this, &parent_layout_node->style());
171 m_resolved_style = style;
172 if (!layout_node()) {
173 if (style->string_or_fallback(CSS::PropertyID::Display, "inline") == "none")
174 return;
175 // We need a new layout tree here!
176 LayoutTreeBuilder tree_builder;
177 tree_builder.build(*this);
178 return;
179 }
180 auto diff = compute_style_difference(layout_node()->style(), *style, document());
181 if (diff == StyleDifference::None)
182 return;
183 layout_node()->set_style(*style);
184 if (diff == StyleDifference::NeedsRelayout) {
185 ASSERT_NOT_REACHED();
186 }
187 if (diff == StyleDifference::NeedsRepaint) {
188 layout_node()->set_needs_display();
189 }
190}
191
192NonnullRefPtr<StyleProperties> Element::computed_style()
193{
194 auto properties = m_resolved_style->clone();
195 if (layout_node() && layout_node()->has_style()) {
196 CSS::PropertyID box_model_metrics[] = {
197 CSS::PropertyID::MarginTop,
198 CSS::PropertyID::MarginBottom,
199 CSS::PropertyID::MarginLeft,
200 CSS::PropertyID::MarginRight,
201 CSS::PropertyID::PaddingTop,
202 CSS::PropertyID::PaddingBottom,
203 CSS::PropertyID::PaddingLeft,
204 CSS::PropertyID::PaddingRight,
205 CSS::PropertyID::BorderTopWidth,
206 CSS::PropertyID::BorderBottomWidth,
207 CSS::PropertyID::BorderLeftWidth,
208 CSS::PropertyID::BorderRightWidth,
209 };
210 for (CSS::PropertyID id : box_model_metrics) {
211 auto prop = layout_node()->style().property(id);
212 if (prop)
213 properties->set_property(id, prop.value());
214 }
215 }
216 return properties;
217}