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

script/dom/encoding/
textdecoderstream.rs
