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

script/dom/encoding/
textencoder.rs
