script/dom/encoding/
textencoder.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 std::ptr;
6
7use dom_struct::dom_struct;
8use js::gc::CustomAutoRooterGuard;
9use js::jsapi::JSObject;
10use js::rust::HandleObject;
11use js::typedarray;
12use js::typedarray::HeapUint8Array;
13use script_bindings::trace::RootedTraceableBox;
14
15use crate::dom::bindings::buffer_source::create_buffer_source;
16use crate::dom::bindings::codegen::Bindings::TextEncoderBinding::{
17    TextEncoderEncodeIntoResult, TextEncoderMethods,
18};
19use crate::dom::bindings::error::Fallible;
20use crate::dom::bindings::reflector::{Reflector, reflect_dom_object_with_proto};
21use crate::dom::bindings::root::DomRoot;
22use crate::dom::bindings::str::{DOMString, USVString};
23use crate::dom::globalscope::GlobalScope;
24use crate::script_runtime::{CanGc, JSContext};
25
26/// <https://encoding.spec.whatwg.org/#textencoder>
27#[dom_struct]
28pub(crate) struct TextEncoder {
29    reflector_: Reflector,
30}
31
32impl TextEncoder {
33    fn new_inherited() -> TextEncoder {
34        TextEncoder {
35            reflector_: Reflector::new(),
36        }
37    }
38
39    fn new(
40        global: &GlobalScope,
41        proto: Option<HandleObject>,
42        can_gc: CanGc,
43    ) -> DomRoot<TextEncoder> {
44        reflect_dom_object_with_proto(
45            Box::new(TextEncoder::new_inherited()),
46            global,
47            proto,
48            can_gc,
49        )
50    }
51}
52
53impl TextEncoderMethods<crate::DomTypeHolder> for TextEncoder {
54    /// <https://encoding.spec.whatwg.org/#dom-textencoder>
55    fn Constructor(
56        global: &GlobalScope,
57        proto: Option<HandleObject>,
58        can_gc: CanGc,
59    ) -> Fallible<DomRoot<TextEncoder>> {
60        Ok(TextEncoder::new(global, proto, can_gc))
61    }
62
63    /// <https://encoding.spec.whatwg.org/#dom-textencoder-encoding>
64    fn Encoding(&self) -> DOMString {
65        DOMString::from("utf-8")
66    }
67
68    /// <https://encoding.spec.whatwg.org/#dom-textencoder-encode>
69    fn Encode(
70        &self,
71        cx: JSContext,
72        input: USVString,
73        can_gc: CanGc,
74    ) -> RootedTraceableBox<HeapUint8Array> {
75        let encoded = input.0.as_bytes();
76
77        rooted!(in(*cx) let mut js_object = ptr::null_mut::<JSObject>());
78        create_buffer_source(cx, encoded, js_object.handle_mut(), can_gc)
79            .expect("Converting input to uint8 array should never fail")
80    }
81
82    /// <https://encoding.spec.whatwg.org/#dom-textencoder-encodeinto>
83    #[expect(unsafe_code)]
84    fn EncodeInto(
85        &self,
86        source: USVString,
87        mut destination: CustomAutoRooterGuard<typedarray::Uint8Array>,
88    ) -> TextEncoderEncodeIntoResult {
89        let available = destination.len();
90
91        // Bail out if the destination has no space available.
92        if available == 0 {
93            return TextEncoderEncodeIntoResult {
94                read: Some(0),
95                written: Some(0),
96            };
97        }
98
99        let mut read = 0;
100        let mut written = 0;
101
102        let dest = unsafe { destination.as_mut_slice() };
103
104        // Step 3, 4, 5, 6
105        // Turn the source into a queue of scalar values.
106        // Iterate over the source values.
107        for result in source.0.chars() {
108            let utf8_len = result.len_utf8();
109            if available - written >= utf8_len {
110                // Step 6.4.1
111                // If destination’s byte length − written is greater than or equal to the number of bytes in result
112                read += if result > '\u{FFFF}' { 2 } else { 1 };
113
114                // Write the bytes in result into destination, with startingOffset set to written.
115                let target = &mut dest[written..written + utf8_len];
116                result.encode_utf8(target);
117
118                // Increment written by the number of bytes in result.
119                written += utf8_len;
120            } else {
121                // Step 6.4.2
122                // Bail out when destination buffer is full.
123                break;
124            }
125        }
126
127        TextEncoderEncodeIntoResult {
128            read: Some(read),
129            written: Some(written as _),
130        }
131    }
132}
script/dom/encoding/textencoder.rs

script/dom/encoding/
textencoder.rs
