script/dom/svg/
svgsvgelement.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use base64::Engine as _;
6use cssparser::{Parser, ParserInput};
7use dom_struct::dom_struct;
8use html5ever::{LocalName, Prefix, local_name, ns};
9use js::context::JSContext;
10use js::rust::HandleObject;
11use layout_api::SVGElementData;
12use servo_url::ServoUrl;
13use style::attr::AttrValue;
14use style::parser::ParserContext;
15use style::stylesheets::Origin;
16use style::values::specified::LengthPercentage;
17use style_traits::ParsingMode;
18use uuid::Uuid;
19use xml5ever::serialize::TraversalScope;
20
21use crate::dom::attr::Attr;
22use crate::dom::bindings::cell::DomRefCell;
23use crate::dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
24use crate::dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
25use crate::dom::bindings::inheritance::Castable;
26use crate::dom::bindings::root::{DomRoot, LayoutDom};
27use crate::dom::bindings::str::DOMString;
28use crate::dom::document::Document;
29use crate::dom::element::{AttributeMutation, Element};
30use crate::dom::node::{
31    ChildrenMutation, CloneChildrenFlag, Node, NodeDamage, NodeTraits, ShadowIncluding,
32    UnbindContext,
33};
34use crate::dom::svg::svggraphicselement::SVGGraphicsElement;
35use crate::dom::virtualmethods::VirtualMethods;
36
37#[dom_struct]
38pub(crate) struct SVGSVGElement {
39    svggraphicselement: SVGGraphicsElement,
40    uuid: String,
41    // The XML source of subtree rooted at this SVG element, serialized into
42    // a base64 encoded `data:` url. This is cached to avoid recomputation
43    // on each layout and must be invalidated when the subtree changes.
44    #[no_trace]
45    cached_serialized_data_url: DomRefCell<Option<Result<ServoUrl, ()>>>,
46}
47
48impl SVGSVGElement {
49    fn new_inherited(
50        local_name: LocalName,
51        prefix: Option<Prefix>,
52        document: &Document,
53    ) -> SVGSVGElement {
54        SVGSVGElement {
55            svggraphicselement: SVGGraphicsElement::new_inherited(local_name, prefix, document),
56            uuid: Uuid::new_v4().to_string(),
57            cached_serialized_data_url: Default::default(),
58        }
59    }
60
61    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
62    pub(crate) fn new(
63        cx: &mut js::context::JSContext,
64        local_name: LocalName,
65        prefix: Option<Prefix>,
66        document: &Document,
67        proto: Option<HandleObject>,
68    ) -> DomRoot<SVGSVGElement> {
69        Node::reflect_node_with_proto(
70            cx,
71            Box::new(SVGSVGElement::new_inherited(local_name, prefix, document)),
72            document,
73            proto,
74        )
75    }
76
77    #[expect(unsafe_code)]
78    pub(crate) fn serialize_and_cache_subtree(&self) {
79        // TODO: https://github.com/servo/servo/issues/43142
80        let mut cx = unsafe { script_bindings::script_runtime::temp_cx() };
81        let cx = &mut cx;
82        let cloned_nodes = self.process_use_elements(cx);
83
84        let serialize_result = self
85            .upcast::<Node>()
86            .xml_serialize(TraversalScope::IncludeNode);
87
88        self.cleanup_cloned_nodes(cx, &cloned_nodes);
89
90        let Ok(xml_source) = serialize_result else {
91            *self.cached_serialized_data_url.borrow_mut() = Some(Err(()));
92            return;
93        };
94
95        let xml_source: String = xml_source.into();
96        let base64_encoded_source = base64::engine::general_purpose::STANDARD.encode(xml_source);
97        let data_url = format!("data:image/svg+xml;base64,{}", base64_encoded_source);
98        match ServoUrl::parse(&data_url) {
99            Ok(url) => *self.cached_serialized_data_url.borrow_mut() = Some(Ok(url)),
100            Err(error) => error!("Unable to parse serialized SVG data url: {error}"),
101        };
102    }
103
104    fn process_use_elements(&self, cx: &mut JSContext) -> Vec<DomRoot<Node>> {
105        let mut cloned_nodes = Vec::new();
106        let root_node = self.upcast::<Node>();
107
108        for node in root_node.traverse_preorder(ShadowIncluding::No) {
109            if let Some(element) = node.downcast::<Element>() {
110                if element.local_name() == &local_name!("use") {
111                    if let Some(cloned) = self.process_single_use_element(cx, element) {
112                        cloned_nodes.push(cloned);
113                    }
114                }
115            }
116        }
117
118        cloned_nodes
119    }
120
121    fn process_single_use_element(
122        &self,
123        cx: &mut JSContext,
124        use_element: &Element,
125    ) -> Option<DomRoot<Node>> {
126        let href = use_element.get_string_attribute(&local_name!("href"));
127        let href_view = href.str();
128        let id_str = href_view.strip_prefix("#")?;
129        let id = DOMString::from(id_str);
130        let document = self.upcast::<Node>().owner_doc();
131        let referenced_element = document.GetElementById(id)?;
132        let referenced_node = referenced_element.upcast::<Node>();
133        let has_svg_ancestor = referenced_node
134            .inclusive_ancestors(ShadowIncluding::No)
135            .any(|ancestor| ancestor.is::<SVGSVGElement>());
136        if !has_svg_ancestor {
137            return None;
138        }
139        let cloned_node = Node::clone(
140            cx,
141            referenced_node,
142            None,
143            CloneChildrenFlag::CloneChildren,
144            None,
145        );
146        let root_node = self.upcast::<Node>();
147        let _ = root_node.AppendChild(cx, &cloned_node);
148
149        Some(cloned_node)
150    }
151
152    fn cleanup_cloned_nodes(&self, cx: &mut JSContext, cloned_nodes: &[DomRoot<Node>]) {
153        if cloned_nodes.is_empty() {
154            return;
155        }
156        let root_node = self.upcast::<Node>();
157
158        for cloned_node in cloned_nodes {
159            let _ = root_node.RemoveChild(cx, cloned_node);
160        }
161    }
162
163    fn invalidate_cached_serialized_subtree(&self) {
164        *self.cached_serialized_data_url.borrow_mut() = None;
165        self.upcast::<Node>().dirty(NodeDamage::Other);
166    }
167}
168
169impl<'dom> LayoutDom<'dom, SVGSVGElement> {
170    #[expect(unsafe_code)]
171    pub(crate) fn data(self) -> SVGElementData<'dom> {
172        let svg_id = self.unsafe_get().uuid.clone();
173        let element = self.upcast::<Element>();
174        let width = element.get_attr_for_layout(&ns!(), &local_name!("width"));
175        let height = element.get_attr_for_layout(&ns!(), &local_name!("height"));
176        let view_box = element.get_attr_for_layout(&ns!(), &local_name!("viewBox"));
177        SVGElementData {
178            source: unsafe {
179                self.unsafe_get()
180                    .cached_serialized_data_url
181                    .borrow_for_layout()
182                    .clone()
183            },
184            width,
185            height,
186            view_box,
187            svg_id,
188        }
189    }
190}
191
192impl VirtualMethods for SVGSVGElement {
193    fn super_type(&self) -> Option<&dyn VirtualMethods> {
194        Some(self.upcast::<SVGGraphicsElement>() as &dyn VirtualMethods)
195    }
196
197    fn attribute_mutated(
198        &self,
199        cx: &mut js::context::JSContext,
200        attr: &Attr,
201        mutation: AttributeMutation,
202    ) {
203        self.super_type()
204            .unwrap()
205            .attribute_mutated(cx, attr, mutation);
206
207        self.invalidate_cached_serialized_subtree();
208    }
209
210    fn attribute_affects_presentational_hints(&self, attr: &Attr) -> bool {
211        match attr.local_name() {
212            &local_name!("width") | &local_name!("height") => true,
213            _ => self
214                .super_type()
215                .unwrap()
216                .attribute_affects_presentational_hints(attr),
217        }
218    }
219
220    fn parse_plain_attribute(&self, name: &LocalName, value: DOMString) -> AttrValue {
221        match *name {
222            local_name!("width") | local_name!("height") => {
223                let value = &value.str();
224                let parser_input = &mut ParserInput::new(value);
225                let parser = &mut Parser::new(parser_input);
226                let doc = self.owner_document();
227                let url = doc.url().into_url().into();
228                let context = ParserContext::new(
229                    Origin::Author,
230                    &url,
231                    None,
232                    ParsingMode::ALLOW_UNITLESS_LENGTH,
233                    doc.quirks_mode(),
234                    /* namespaces = */ Default::default(),
235                    None,
236                    None,
237                );
238                let val = LengthPercentage::parse_quirky(
239                    &context,
240                    parser,
241                    style::values::specified::AllowQuirks::Always,
242                );
243                AttrValue::LengthPercentage(value.to_string(), val.ok())
244            },
245            _ => self
246                .super_type()
247                .unwrap()
248                .parse_plain_attribute(name, value),
249        }
250    }
251
252    fn children_changed(&self, cx: &mut JSContext, mutation: &ChildrenMutation) {
253        if let Some(super_type) = self.super_type() {
254            super_type.children_changed(cx, mutation);
255        }
256
257        self.invalidate_cached_serialized_subtree();
258    }
259
260    fn unbind_from_tree(&self, cx: &mut js::context::JSContext, context: &UnbindContext<'_>) {
261        if let Some(s) = self.super_type() {
262            s.unbind_from_tree(cx, context);
263        }
264        let owner_window = self.owner_window();
265        self.owner_window()
266            .image_cache()
267            .evict_rasterized_image(&self.uuid);
268        let data_url = self.cached_serialized_data_url.borrow().clone();
269        if let Some(Ok(url)) = data_url {
270            owner_window.layout_mut().remove_cached_image(&url);
271            owner_window.image_cache().evict_completed_image(
272                &url,
273                owner_window.origin().immutable(),
274                &None,
275            );
276        }
277        self.invalidate_cached_serialized_subtree();
278    }
279}
script/dom/svg/svgsvgelement.rs

script/dom/svg/
svgsvgelement.rs
