script/dom/encoding/
textdecoderstream.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::rc::Rc;
6
7use dom_struct::dom_struct;
8use encoding_rs::Encoding;
9use js::conversions::{FromJSValConvertible, ToJSValConvertible};
10use js::jsval::UndefinedValue;
11use js::rust::{HandleObject as SafeHandleObject, HandleValue as SafeHandleValue};
12
13use crate::DomTypes;
14use crate::dom::bindings::codegen::Bindings::TextDecoderBinding;
15use crate::dom::bindings::codegen::Bindings::TextDecoderStreamBinding::TextDecoderStreamMethods;
16use crate::dom::bindings::codegen::UnionTypes::ArrayBufferViewOrArrayBuffer;
17use crate::dom::bindings::error::{Error, Fallible};
18use crate::dom::bindings::reflector::{Reflector, reflect_dom_object_with_proto_and_cx};
19use crate::dom::bindings::root::{Dom, DomRoot};
20use crate::dom::bindings::str::DOMString;
21use crate::dom::encoding::textdecodercommon::TextDecoderCommon;
22use crate::dom::globalscope::GlobalScope;
23use crate::dom::stream::transformstreamdefaultcontroller::TransformerType;
24use crate::dom::types::{TransformStream, TransformStreamDefaultController};
25use crate::script_runtime::CanGc;
26
27/// <https://encoding.spec.whatwg.org/#decode-and-enqueue-a-chunk>
28#[expect(unsafe_code)]
29pub(crate) fn decode_and_enqueue_a_chunk(
30    cx: &mut js::context::JSContext,
31    global: &GlobalScope,
32    chunk: SafeHandleValue,
33    decoder: &TextDecoderCommon,
34    controller: &TransformStreamDefaultController,
35) -> Fallible<()> {
36    // Step 1. Let bufferSource be the result of converting chunk to an AllowSharedBufferSource.
37    let conversion_result = unsafe {
38        ArrayBufferViewOrArrayBuffer::from_jsval(cx.raw_cx(), chunk, ()).map_err(|_| {
39            Error::Type(c"Unable to convert chunk into ArrayBuffer or ArrayBufferView".to_owned())
40        })?
41    };
42    let buffer_source = conversion_result.get_success_value().ok_or_else(|| {
43        Error::Type(c"Unable to convert chunk into ArrayBuffer or ArrayBufferView".to_owned())
44    })?;
45
46    // Step 2. Push a copy of bufferSource to decoder’s I/O queue.
47    // Step 3. Let output be the I/O queue of scalar values « end-of-queue ».
48    // Step 4. While true:
49    // Step 4.1 Let item be the result of reading from decoder’s I/O queue.
50    // Step 4.2 If item is end-of-queue:
51    // Step 4.2.1 Let outputChunk be the result of running serialize I/O queue with decoder and output.
52    // Step 4.2.3 Return.
53    // Step 4.3 Let result be the result of processing an item with item, decoder’s decoder,
54    //      decoder’s I/O queue, output, and decoder’s error mode.
55    // Step 4.4 If result is error, then throw a TypeError.
56    let output_chunk = decoder.decode(Some(buffer_source), false)?;
57
58    // Step 4.2.2 If outputChunk is not the empty string, then enqueue
59    //      outputChunk in decoder’s transform.
60    if output_chunk.is_empty() {
61        return Ok(());
62    }
63    rooted!(&in(cx) let mut rval = UndefinedValue());
64    unsafe { output_chunk.to_jsval(cx.raw_cx(), rval.handle_mut()) };
65    controller.enqueue(cx, global, rval.handle())
66}
67
68/// <https://encoding.spec.whatwg.org/#flush-and-enqueue>
69#[expect(unsafe_code)]
70pub(crate) fn flush_and_enqueue(
71    cx: &mut js::context::JSContext,
72    global: &GlobalScope,
73    decoder: &TextDecoderCommon,
74    controller: &TransformStreamDefaultController,
75) -> Fallible<()> {
76    // Step 1. Let output be the I/O queue of scalar values « end-of-queue ».
77    // Step 2. While true:
78    // Step 2.1 Let item be the result of reading from decoder’s I/O queue.
79    // Step 2.2 Let result be the result of processing an item with item,
80    //      decoder’s decoder, decoder’s I/O queue, output, and decoder’s error mode.
81    // Step 2.3 If result is finished:
82    // Step 2.3.1 Let outputChunk be the result of running serialize I/O queue
83    //      with decoder and output.
84    // Step 2.3.3 Return.
85    // Step 2.3.4 Otherwise, if result is error, throw a TypeError.
86    let output_chunk = decoder.decode(None, true)?;
87
88    // Step 2.3.2 If outputChunk is not the empty string, then enqueue
89    //      outputChunk in decoder’s transform.
90    if output_chunk.is_empty() {
91        return Ok(());
92    }
93    rooted!(&in(cx) let mut rval = UndefinedValue());
94    unsafe { output_chunk.to_jsval(cx.raw_cx(), rval.handle_mut()) };
95    controller.enqueue(cx, global, rval.handle())
96}
97
98/// <https://encoding.spec.whatwg.org/#textdecoderstream>
99#[dom_struct]
100pub(crate) struct TextDecoderStream {
101    reflector_: Reflector,
102
103    /// <https://encoding.spec.whatwg.org/#textdecodercommon>
104    #[conditional_malloc_size_of]
105    decoder: Rc<TextDecoderCommon>,
106
107    /// <https://streams.spec.whatwg.org/#generictransformstream>
108    transform: Dom<TransformStream>,
109}
110
111#[expect(non_snake_case)]
112impl TextDecoderStream {
113    fn new_inherited(
114        decoder: Rc<TextDecoderCommon>,
115        transform: &TransformStream,
116    ) -> TextDecoderStream {
117        TextDecoderStream {
118            reflector_: Reflector::new(),
119            decoder,
120            transform: Dom::from_ref(transform),
121        }
122    }
123
124    fn new_with_proto(
125        cx: &mut js::context::JSContext,
126        global: &GlobalScope,
127        proto: Option<SafeHandleObject>,
128        encoding: &'static Encoding,
129        fatal: bool,
130        ignoreBOM: bool,
131    ) -> Fallible<DomRoot<Self>> {
132        let decoder = Rc::new(TextDecoderCommon::new_inherited(encoding, fatal, ignoreBOM));
133        let transformer_type = TransformerType::Decoder(decoder.clone());
134
135        let transform_stream = TransformStream::new_with_proto(global, None, CanGc::from_cx(cx));
136        transform_stream.set_up(cx, global, transformer_type)?;
137
138        Ok(reflect_dom_object_with_proto_and_cx(
139            Box::new(TextDecoderStream::new_inherited(decoder, &transform_stream)),
140            global,
141            proto,
142            cx,
143        ))
144    }
145}
146
147impl TextDecoderStreamMethods<crate::DomTypeHolder> for TextDecoderStream {
148    /// <https://encoding.spec.whatwg.org/#dom-textdecoderstream>
149    fn Constructor(
150        cx: &mut js::context::JSContext,
151        global: &GlobalScope,
152        proto: Option<SafeHandleObject>,
153        label: DOMString,
154        options: &TextDecoderBinding::TextDecoderOptions,
155    ) -> Fallible<DomRoot<TextDecoderStream>> {
156        let encoding = match Encoding::for_label_no_replacement(&label.as_bytes()) {
157            Some(enc) => enc,
158            None => {
159                return Err(Error::Range(
160                    c"The given encoding is not supported".to_owned(),
161                ));
162            },
163        };
164
165        Self::new_with_proto(
166            cx,
167            global,
168            proto,
169            encoding,
170            options.fatal,
171            options.ignoreBOM,
172        )
173    }
174
175    /// <https://encoding.spec.whatwg.org/#dom-textdecoder-encoding>
176    fn Encoding(&self) -> DOMString {
177        DOMString::from(self.decoder.encoding().name().to_ascii_lowercase())
178    }
179
180    /// <https://encoding.spec.whatwg.org/#dom-textdecoder-fatal>
181    fn Fatal(&self) -> bool {
182        self.decoder.fatal()
183    }
184
185    /// <https://encoding.spec.whatwg.org/#dom-textdecoder-ignorebom>
186    fn IgnoreBOM(&self) -> bool {
187        self.decoder.ignore_bom()
188    }
189
190    /// <https://streams.spec.whatwg.org/#dom-generictransformstream-readable>
191    fn Readable(&self) -> DomRoot<<crate::DomTypeHolder as DomTypes>::ReadableStream> {
192        self.transform.get_readable()
193    }
194
195    /// <https://streams.spec.whatwg.org/#dom-generictransformstream-writable>
196    fn Writable(&self) -> DomRoot<<crate::DomTypeHolder as DomTypes>::WritableStream> {
197        self.transform.get_writable()
198    }
199}
script/dom/encoding/textdecoderstream.rs

script/dom/encoding/
textdecoderstream.rs
