script/dom/
domstringmap.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 dom_struct::dom_struct;
6use html5ever::{LocalName, ns};
7use js::context::NoGC;
8use script_bindings::reflector::{Reflector, reflect_dom_object};
9
10use crate::dom::bindings::codegen::Bindings::DOMStringMapBinding::DOMStringMapMethods;
11use crate::dom::bindings::error::{Error, ErrorResult};
12use crate::dom::bindings::inheritance::Castable;
13use crate::dom::bindings::root::{Dom, DomRoot};
14use crate::dom::bindings::str::DOMString;
15use crate::dom::bindings::xmlname::matches_name_production;
16use crate::dom::element::Element;
17use crate::dom::html::htmlelement::HTMLElement;
18use crate::dom::node::NodeTraits;
19use crate::script_runtime::CanGc;
20
21#[dom_struct]
22pub(crate) struct DOMStringMap {
23    reflector_: Reflector,
24    element: Dom<HTMLElement>,
25}
26
27static DATA_PREFIX: &str = "data-";
28static DATA_HYPHEN_SEPARATOR: char = '\x2d';
29
30/// <https://html.spec.whatwg.org/multipage/#concept-domstringmap-pairs>
31fn to_camel_case(name: &str) -> Option<DOMString> {
32    // Step 2. For each content attribute on the DOMStringMap's associated element whose
33    // first five characters are the string "data-" and whose remaining characters (if any)
34    // do not include any ASCII upper alphas, in the order that those attributes
35    // are listed in the element's attribute list,
36    // add a name-value pair to list whose name is the attribute's name with the first
37    // five characters removed and whose value is the attribute's value.
38    let name = name.strip_prefix(DATA_PREFIX)?;
39    let has_uppercase = name.chars().any(|curr_char| curr_char.is_ascii_uppercase());
40    if has_uppercase {
41        return None;
42    }
43    // Step 3. For each name in list, for each U+002D HYPHEN-MINUS character (-)
44    // in the name that is followed by an ASCII lower alpha, remove the
45    // U+002D HYPHEN-MINUS character (-) and replace the character that followed
46    // it by the same character converted to ASCII uppercase.
47    let mut result = String::with_capacity(name.len().saturating_sub(DATA_PREFIX.len()));
48    let mut name_chars = name.chars().peekable();
49    while let Some(curr_char) = name_chars.next() {
50        // Note that we first need to peek, since we shouldn't advance the iterator twice
51        // in case there are two consecutive dashes and then followed by a ASCII lower alpha
52        if curr_char == DATA_HYPHEN_SEPARATOR &&
53            name_chars
54                .peek()
55                .is_some_and(|next_char| next_char.is_ascii_lowercase())
56        {
57            result.push(
58                name_chars
59                    .next()
60                    .expect("Already called peek")
61                    .to_ascii_uppercase(),
62            );
63            continue;
64        }
65        result.push(curr_char);
66    }
67    // Step 1. Let list be an empty list of name-value pairs.
68    // Step 4. Return list.
69    //
70    // We do the iteration in the calling function, to avoid needlessly computing attribute
71    // values when we only need the names. Therefore, we only return the name.
72    Some(DOMString::from(result))
73}
74
75/// <https://html.spec.whatwg.org/multipage/#dom-domstringmap-setitem>
76/// and <https://html.spec.whatwg.org/multipage/#dom-domstringmap-removeitem>
77fn to_snake_case(name: &DOMString, should_throw: bool) -> Option<String> {
78    let name = name.str();
79    let mut result = String::with_capacity(DATA_PREFIX.len() + name.len());
80    // > Insert the string data- at the front of name.
81    result.push_str(DATA_PREFIX);
82    let mut name_chars = name.chars();
83    while let Some(curr_char) = name_chars.next() {
84        if curr_char == DATA_HYPHEN_SEPARATOR {
85            result.push(curr_char);
86
87            if let Some(next_char) = name_chars.next() {
88                // Only relevant for https://html.spec.whatwg.org/multipage/#dom-domstringmap-setitem
89                //
90                // > If name contains a U+002D HYPHEN-MINUS character (-) followed by an ASCII lower alpha,
91                // > then throw a "SyntaxError" DOMException.
92                if next_char.is_ascii_lowercase() {
93                    if should_throw {
94                        return None;
95                    }
96                    result.push(next_char);
97                } else {
98                    // > For each ASCII upper alpha in name, insert a U+002D HYPHEN-MINUS character (-) before the character
99                    // > and replace the character with the same character converted to ASCII lowercase.
100                    result.push(DATA_HYPHEN_SEPARATOR);
101                    result.push(next_char.to_ascii_lowercase());
102                }
103            }
104        } else {
105            // > For each ASCII upper alpha in name, insert a U+002D HYPHEN-MINUS character (-) before the character
106            // > and replace the character with the same character converted to ASCII lowercase.
107            if curr_char.is_ascii_uppercase() {
108                result.push(DATA_HYPHEN_SEPARATOR);
109                result.push(curr_char.to_ascii_lowercase());
110            } else {
111                result.push(curr_char);
112            }
113        }
114    }
115    Some(result)
116}
117
118impl DOMStringMap {
119    fn new_inherited(element: &HTMLElement) -> DOMStringMap {
120        DOMStringMap {
121            reflector_: Reflector::new(),
122            element: Dom::from_ref(element),
123        }
124    }
125
126    pub(crate) fn new(element: &HTMLElement, can_gc: CanGc) -> DomRoot<DOMStringMap> {
127        reflect_dom_object(
128            Box::new(DOMStringMap::new_inherited(element)),
129            &*element.owner_window(),
130            can_gc,
131        )
132    }
133
134    fn as_element(&self) -> &Element {
135        self.element.upcast::<Element>()
136    }
137}
138
139// https://html.spec.whatwg.org/multipage/#domstringmap
140impl DOMStringMapMethods<crate::DomTypeHolder> for DOMStringMap {
141    /// <https://html.spec.whatwg.org/multipage/#dom-domstringmap-removeitem>
142    fn NamedDeleter(&self, cx: &mut js::context::JSContext, name: DOMString) {
143        // Step 1. For each ASCII upper alpha in name, insert a U+002D HYPHEN-MINUS character (-) before the character
144        // and replace the character with the same character converted to ASCII lowercase.
145        // Step 2. Insert the string data- at the front of name.
146        let name = to_snake_case(&name, false).expect("Must always succeed");
147        // Step 3. Remove an attribute by name given name and the DOMStringMap's associated element.
148        self.as_element()
149            .remove_attribute(cx, &ns!(), &LocalName::from(name));
150    }
151
152    /// <https://html.spec.whatwg.org/multipage/#dom-domstringmap-setitem>
153    fn NamedSetter(
154        &self,
155        cx: &mut js::context::JSContext,
156        name: DOMString,
157        value: DOMString,
158    ) -> ErrorResult {
159        // Step 2. For each ASCII upper alpha in name, insert a U+002D HYPHEN-MINUS character (-)
160        // before the character and replace the character with the same character converted to ASCII lowercase.
161        // Step 3. Insert the string data- at the front of name.
162        let Some(name) = to_snake_case(&name, true) else {
163            // Step 1. If name contains a U+002D HYPHEN-MINUS character (-) followed by an ASCII lower alpha,
164            // then throw a "SyntaxError" DOMException.
165            return Err(Error::Syntax(None));
166        };
167        // Step 4. If name is not a valid attribute local name, then throw an "InvalidCharacterError" DOMException.
168        if !matches_name_production(&name) {
169            return Err(Error::InvalidCharacter(None));
170        }
171        // Step 5. Set an attribute value for the DOMStringMap's associated element using name and value.
172        let name = LocalName::from(name);
173        let element = self.as_element();
174        let value = element.parse_attribute(&ns!(), &name, value);
175        element.set_attribute_with_namespace(cx, name.clone(), value, name, ns!(), None);
176        Ok(())
177    }
178
179    /// <https://html.spec.whatwg.org/multipage/#dom-domstringmap-nameditem>
180    fn NamedGetter(&self, name: DOMString) -> Option<DOMString> {
181        // > To determine the value of a named property name for a DOMStringMap,
182        // > return the value component of the name-value pair whose name component is
183        // > name in the list returned from getting the DOMStringMap's name-value pairs.
184        self.as_element()
185            .attrs()
186            .borrow()
187            .iter()
188            .find(|attr| to_camel_case(attr.local_name()).as_ref() == Some(&name))
189            .map(|attr| DOMString::from(&**attr.value()))
190    }
191
192    /// <https://html.spec.whatwg.org/multipage/#the-domstringmap-interface:supported-property-names>
193    fn SupportedPropertyNames(&self, _: &NoGC) -> Vec<DOMString> {
194        // > The supported property names on a DOMStringMap object at any instant are
195        // > the names of each pair returned from getting the DOMStringMap's name-value
196        // > pairs at that instant, in the order returned.
197        self.as_element()
198            .attrs()
199            .borrow()
200            .iter()
201            .filter_map(|attr| to_camel_case(attr.local_name()))
202            .collect()
203    }
204}
script/dom/domstringmap.rs

script/dom/
domstringmap.rs
