script/dom/stream/
defaultteereadrequest.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 http://mozilla.org/MPL/2.0/. */
4
5use std::cell::Cell;
6use std::rc::Rc;
7
8use dom_struct::dom_struct;
9use js::context::JSContext;
10use js::jsapi::Heap;
11use js::jsval::{JSVal, UndefinedValue};
12use js::realm::AutoRealm;
13use js::rust::HandleValue as SafeHandleValue;
14use script_bindings::reflector::{Reflector, reflect_dom_object};
15
16use crate::dom::bindings::reflector::DomGlobal;
17use crate::dom::bindings::root::{Dom, DomRoot};
18use crate::dom::bindings::structuredclone;
19use crate::dom::bindings::trace::RootedTraceableBox;
20use crate::dom::globalscope::GlobalScope;
21use crate::dom::promise::Promise;
22use crate::dom::stream::defaultteeunderlyingsource::DefaultTeeUnderlyingSource;
23use crate::dom::stream::readablestream::ReadableStream;
24use crate::microtask::{Microtask, MicrotaskRunnable};
25use crate::realms::enter_auto_realm;
26use crate::script_runtime::CanGc;
27
28#[derive(JSTraceable, MallocSizeOf)]
29#[cfg_attr(crown, expect(crown::unrooted_must_root))]
30pub(crate) struct DefaultTeeReadRequestMicrotask {
31    #[ignore_malloc_size_of = "mozjs"]
32    chunk: Box<Heap<JSVal>>,
33    tee_read_request: Dom<DefaultTeeReadRequest>,
34}
35
36impl MicrotaskRunnable for DefaultTeeReadRequestMicrotask {
37    fn handler(&self, cx: &mut JSContext) {
38        self.tee_read_request.chunk_steps(cx, &self.chunk);
39    }
40
41    fn enter_realm<'cx>(&self, cx: &'cx mut js::context::JSContext) -> AutoRealm<'cx> {
42        enter_auto_realm(cx, &*self.tee_read_request)
43    }
44}
45
46#[dom_struct]
47/// <https://streams.spec.whatwg.org/#ref-for-read-request%E2%91%A2>
48pub(crate) struct DefaultTeeReadRequest {
49    reflector_: Reflector,
50    stream: Dom<ReadableStream>,
51    branch_1: Dom<ReadableStream>,
52    branch_2: Dom<ReadableStream>,
53    #[conditional_malloc_size_of]
54    reading: Rc<Cell<bool>>,
55    #[conditional_malloc_size_of]
56    read_again: Rc<Cell<bool>>,
57    #[conditional_malloc_size_of]
58    canceled_1: Rc<Cell<bool>>,
59    #[conditional_malloc_size_of]
60    canceled_2: Rc<Cell<bool>>,
61    #[conditional_malloc_size_of]
62    clone_for_branch_2: Rc<Cell<bool>>,
63    #[conditional_malloc_size_of]
64    cancel_promise: Rc<Promise>,
65    tee_underlying_source: Dom<DefaultTeeUnderlyingSource>,
66}
67impl DefaultTeeReadRequest {
68    #[expect(clippy::too_many_arguments)]
69    pub(crate) fn new(
70        stream: &ReadableStream,
71        branch_1: &ReadableStream,
72        branch_2: &ReadableStream,
73        reading: Rc<Cell<bool>>,
74        read_again: Rc<Cell<bool>>,
75        canceled_1: Rc<Cell<bool>>,
76        canceled_2: Rc<Cell<bool>>,
77        clone_for_branch_2: Rc<Cell<bool>>,
78        cancel_promise: Rc<Promise>,
79        tee_underlying_source: &DefaultTeeUnderlyingSource,
80        can_gc: CanGc,
81    ) -> DomRoot<Self> {
82        reflect_dom_object(
83            Box::new(DefaultTeeReadRequest {
84                reflector_: Reflector::new(),
85                stream: Dom::from_ref(stream),
86                branch_1: Dom::from_ref(branch_1),
87                branch_2: Dom::from_ref(branch_2),
88                reading,
89                read_again,
90                canceled_1,
91                canceled_2,
92                clone_for_branch_2,
93                cancel_promise,
94                tee_underlying_source: Dom::from_ref(tee_underlying_source),
95            }),
96            &*stream.global(),
97            can_gc,
98        )
99    }
100    /// Call into cancel of the stream,
101    /// <https://streams.spec.whatwg.org/#readable-stream-cancel>
102    pub(crate) fn stream_cancel(
103        &self,
104        cx: &mut JSContext,
105        global: &GlobalScope,
106        reason: SafeHandleValue,
107    ) {
108        self.stream.cancel(cx, global, reason);
109    }
110    /// Enqueue a microtask to perform the chunk steps
111    /// <https://streams.spec.whatwg.org/#ref-for-read-request-chunk-steps%E2%91%A2>
112    pub(crate) fn enqueue_chunk_steps(&self, chunk: RootedTraceableBox<Heap<JSVal>>) {
113        // Queue a microtask to perform the following steps:
114        let tee_read_request_chunk = DefaultTeeReadRequestMicrotask {
115            chunk: Heap::boxed(*chunk.handle()),
116            tee_read_request: Dom::from_ref(self),
117        };
118        self.stream
119            .global()
120            .enqueue_microtask(Microtask::ReadableStreamTeeReadRequest(
121                tee_read_request_chunk,
122            ));
123    }
124    /// <https://streams.spec.whatwg.org/#ref-for-read-request-chunk-steps%E2%91%A2>
125    #[expect(clippy::borrowed_box)]
126    pub(crate) fn chunk_steps(&self, cx: &mut JSContext, chunk: &Box<Heap<JSVal>>) {
127        let global = &self.stream.global();
128        // Set readAgain to false.
129        self.read_again.set(false);
130        // Let chunk1 and chunk2 be chunk.
131        let chunk1 = chunk;
132        let chunk2 = chunk;
133
134        rooted!(&in(cx) let chunk1_value = chunk1.get());
135        rooted!(&in(cx) let chunk2_value = chunk2.get());
136        // If canceled_2 is false and cloneForBranch2 is true,
137        if !self.canceled_2.get() && self.clone_for_branch_2.get() {
138            // Let cloneResult be StructuredClone(chunk2).
139            rooted!(&in(cx) let mut clone_result = UndefinedValue());
140            let data = structuredclone::write(cx, chunk2_value.handle(), None).unwrap();
141            // If cloneResult is an abrupt completion,
142            if structuredclone::read(cx, global, data, clone_result.handle_mut()).is_err() {
143                // Perform ! ReadableStreamDefaultControllerError(branch_1.[[controller]], cloneResult.[[Value]]).
144                self.readable_stream_default_controller_error(
145                    cx,
146                    &self.branch_1,
147                    clone_result.handle(),
148                );
149
150                // Perform ! ReadableStreamDefaultControllerError(branch_2.[[controller]], cloneResult.[[Value]]).
151                self.readable_stream_default_controller_error(
152                    cx,
153                    &self.branch_2,
154                    clone_result.handle(),
155                );
156                // Resolve cancelPromise with ! ReadableStreamCancel(stream, cloneResult.[[Value]]).
157                self.stream_cancel(cx, global, clone_result.handle());
158                // Return.
159                return;
160            } else {
161                // Otherwise, set chunk2 to cloneResult.[[Value]].
162                chunk2.set(*clone_result);
163            }
164        }
165        // If canceled_1 is false, perform ! ReadableStreamDefaultControllerEnqueue(branch_1.[[controller]], chunk1).
166        if !self.canceled_1.get() {
167            self.readable_stream_default_controller_enqueue(
168                cx,
169                &self.branch_1,
170                chunk1_value.handle(),
171            );
172        }
173        // If canceled_2 is false, perform ! ReadableStreamDefaultControllerEnqueue(branch_2.[[controller]], chunk2).
174        if !self.canceled_2.get() {
175            self.readable_stream_default_controller_enqueue(
176                cx,
177                &self.branch_2,
178                chunk2_value.handle(),
179            );
180        }
181        // Set reading to false.
182        self.reading.set(false);
183        // If readAgain is true, perform pullAlgorithm.
184        if self.read_again.get() {
185            self.pull_algorithm(cx);
186        }
187    }
188    /// <https://streams.spec.whatwg.org/#read-request-close-steps>
189    pub(crate) fn close_steps(&self, cx: &mut JSContext) {
190        // Set reading to false.
191        self.reading.set(false);
192        // If canceled_1 is false, perform ! ReadableStreamDefaultControllerClose(branch_1.[[controller]]).
193        if !self.canceled_1.get() {
194            self.readable_stream_default_controller_close(cx, &self.branch_1);
195        }
196        // If canceled_2 is false, perform ! ReadableStreamDefaultControllerClose(branch_2.[[controller]]).
197        if !self.canceled_2.get() {
198            self.readable_stream_default_controller_close(cx, &self.branch_2);
199        }
200        // If canceled_1 is false or canceled_2 is false, resolve cancelPromise with undefined.
201        if !self.canceled_1.get() || !self.canceled_2.get() {
202            self.cancel_promise.resolve_native(&(), CanGc::from_cx(cx));
203        }
204    }
205    /// <https://streams.spec.whatwg.org/#read-request-error-steps>
206    pub(crate) fn error_steps(&self) {
207        // Set reading to false.
208        self.reading.set(false);
209    }
210    /// Call into enqueue of the default controller of a stream,
211    /// <https://streams.spec.whatwg.org/#readable-stream-default-controller-enqueue>
212    fn readable_stream_default_controller_enqueue(
213        &self,
214        cx: &mut JSContext,
215        stream: &ReadableStream,
216        chunk: SafeHandleValue,
217    ) {
218        stream
219            .get_default_controller()
220            .enqueue(cx, chunk)
221            .expect("enqueue failed for stream controller in DefaultTeeReadRequest");
222    }
223
224    /// Call into close of the default controller of a stream,
225    /// <https://streams.spec.whatwg.org/#readable-stream-default-controller-close>
226    fn readable_stream_default_controller_close(
227        &self,
228        cx: &mut JSContext,
229        stream: &ReadableStream,
230    ) {
231        stream.get_default_controller().close(cx);
232    }
233
234    /// Call into error of the default controller of stream,
235    /// <https://streams.spec.whatwg.org/#readable-stream-default-controller-error>
236    fn readable_stream_default_controller_error(
237        &self,
238        cx: &mut JSContext,
239        stream: &ReadableStream,
240        error: SafeHandleValue,
241    ) {
242        stream.get_default_controller().error(cx, error);
243    }
244
245    pub(crate) fn pull_algorithm(&self, cx: &mut JSContext) {
246        self.tee_underlying_source.pull_algorithm(cx);
247    }
248}
script/dom/stream/defaultteereadrequest.rs

script/dom/stream/
defaultteereadrequest.rs
