script/dom/globalscope/
messageport.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, RefCell};
6use std::rc::Rc;
7
8use dom_struct::dom_struct;
9use js::context::JSContext;
10use js::conversions::ToJSValConvertible;
11use js::jsapi::JSObject;
12use js::jsval::UndefinedValue;
13use js::rust::{CustomAutoRooterGuard, HandleValue};
14use rustc_hash::FxHashMap;
15use script_bindings::callback::RootedCallback;
16use script_bindings::js::JS_NewObject;
17use script_bindings::reflector::reflect_weak_referenceable_dom_object;
18use script_bindings::structuredclone::StructuredData;
19use servo_base::id::{MessagePortId, MessagePortIndex};
20use servo_constellation_traits::{MessagePortImpl, PortMessageTask};
21
22use crate::dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
23use crate::dom::bindings::codegen::Bindings::MessagePortBinding::{
24    MessagePortMethods, StructuredSerializeOptions,
25};
26use crate::dom::bindings::conversions::root_from_object;
27use crate::dom::bindings::error::{Error, ErrorResult, ErrorToJsval, Fallible};
28use crate::dom::bindings::inheritance::Castable;
29use crate::dom::bindings::reflector::DomGlobal;
30use crate::dom::bindings::root::DomRoot;
31use crate::dom::bindings::structuredclone;
32use crate::dom::bindings::transferable::Transferable;
33use crate::dom::bindings::utils::set_dictionary_property;
34use crate::dom::eventtarget::EventTarget;
35use crate::dom::globalscope::GlobalScope;
36
37#[dom_struct]
38/// The MessagePort used in the DOM.
39pub(crate) struct MessagePort {
40    eventtarget: EventTarget,
41    #[no_trace]
42    message_port_id: MessagePortId,
43    #[no_trace]
44    entangled_port: RefCell<Option<MessagePortId>>,
45    detached: Cell<bool>,
46}
47
48impl MessagePort {
49    fn new_inherited(message_port_id: MessagePortId) -> MessagePort {
50        MessagePort {
51            eventtarget: EventTarget::new_inherited(),
52            entangled_port: RefCell::new(None),
53            detached: Cell::new(false),
54            message_port_id,
55        }
56    }
57
58    /// <https://html.spec.whatwg.org/multipage/#create-a-new-messageport-object>
59    pub(crate) fn new(cx: &mut JSContext, owner: &GlobalScope) -> DomRoot<MessagePort> {
60        let port_id = MessagePortId::new();
61        reflect_weak_referenceable_dom_object(
62            cx,
63            Rc::new(MessagePort::new_inherited(port_id)),
64            owner,
65        )
66    }
67
68    /// Create a new port for an incoming transfer-received one.
69    pub(crate) fn new_transferred(
70        cx: &mut JSContext,
71        owner: &GlobalScope,
72        transferred_port: MessagePortId,
73        entangled_port: Option<MessagePortId>,
74    ) -> DomRoot<MessagePort> {
75        reflect_weak_referenceable_dom_object(
76            cx,
77            Rc::new(MessagePort {
78                message_port_id: transferred_port,
79                eventtarget: EventTarget::new_inherited(),
80                detached: Cell::new(false),
81                entangled_port: RefCell::new(entangled_port),
82            }),
83            owner,
84        )
85    }
86
87    /// <https://html.spec.whatwg.org/multipage/#entangle>
88    pub(crate) fn entangle(&self, other_id: MessagePortId) {
89        *self.entangled_port.borrow_mut() = Some(other_id);
90    }
91
92    /// <https://html.spec.whatwg.org/multipage/#disentangle>
93    pub(crate) fn disentangle(&self) -> Option<MessagePortId> {
94        // Disentangle initiatorPort and otherPort, so that they are no longer entangled or associated with each other.
95        // Note: called from `disentangle_port` in the global, where the rest happens.
96        self.entangled_port.borrow_mut().take()
97    }
98
99    /// Has the port been disentangled?
100    /// Used when starting the port to fire the `close` event,
101    /// to cover the case of a disentanglement while in transfer.
102    pub(crate) fn disentangled(&self) -> bool {
103        self.entangled_port.borrow().is_none()
104    }
105
106    pub(crate) fn message_port_id(&self) -> &MessagePortId {
107        &self.message_port_id
108    }
109
110    /// <https://html.spec.whatwg.org/multipage/#handler-messageport-onmessage>
111    fn set_onmessage(
112        &self,
113        cx: &mut JSContext,
114        listener: Option<RootedCallback<EventHandlerNonNull>>,
115    ) {
116        let eventtarget = self.upcast::<EventTarget>();
117        eventtarget.set_event_handler_common(cx, "message", listener);
118    }
119
120    /// <https://html.spec.whatwg.org/multipage/#message-port-post-message-steps>
121    #[expect(unsafe_code)]
122    fn post_message_impl(
123        &self,
124        cx: &mut JSContext,
125        message: HandleValue,
126        transfer: CustomAutoRooterGuard<Vec<*mut JSObject>>,
127    ) -> ErrorResult {
128        if self.detached.get() {
129            return Ok(());
130        }
131
132        // Step 1 is the transfer argument.
133
134        let target_port = self.entangled_port.borrow();
135
136        // Step 3
137        let mut doomed = false;
138
139        let ports = transfer
140            .iter()
141            .filter_map(|&obj| unsafe { root_from_object::<MessagePort>(cx, obj).ok() });
142        for port in ports {
143            // Step 2
144            if port.message_port_id() == self.message_port_id() {
145                return Err(Error::DataClone(None));
146            }
147
148            // Step 4
149            if let Some(target_id) = target_port.as_ref() &&
150                port.message_port_id() == target_id
151            {
152                doomed = true;
153            }
154        }
155
156        // Step 5
157        let data = structuredclone::write(cx, message, Some(transfer))?;
158
159        if doomed {
160            // TODO: The spec says to optionally report such a case to a dev console.
161            return Ok(());
162        }
163
164        // Step 6, done in MessagePortImpl.
165
166        let incumbent = match GlobalScope::incumbent() {
167            None => unreachable!("postMessage called with no incumbent global"),
168            Some(incumbent) => incumbent,
169        };
170
171        // Step 7
172        let task = PortMessageTask {
173            origin: incumbent.origin().immutable().clone(),
174            data,
175        };
176
177        // Have the global proxy this call to the corresponding MessagePortImpl.
178        self.global()
179            .post_messageport_msg(*self.message_port_id(), task);
180        Ok(())
181    }
182
183    /// <https://streams.spec.whatwg.org/#abstract-opdef-crossrealmtransformsenderror>
184    pub(crate) fn cross_realm_transform_send_error(&self, cx: &mut JSContext, error: HandleValue) {
185        // Perform PackAndPostMessage(port, "error", error),
186        // discarding the result.
187        let _ = self.pack_and_post_message(cx, "error", error);
188    }
189
190    /// <https://streams.spec.whatwg.org/#abstract-opdef-packandpostmessagehandlingerror>
191    pub(crate) fn pack_and_post_message_handling_error(
192        &self,
193        cx: &mut JSContext,
194        type_: &str,
195        value: HandleValue,
196    ) -> ErrorResult {
197        // Let result be PackAndPostMessage(port, type, value).
198        let result = self.pack_and_post_message(cx, type_, value);
199
200        // If result is an abrupt completion,
201        if let Err(error) = result.as_ref() {
202            // Perform ! CrossRealmTransformSendError(port, result.[[Value]]).
203            rooted!(&in(cx) let mut rooted_error = UndefinedValue());
204            error
205                .clone()
206                .to_jsval(cx, &self.global(), rooted_error.handle_mut());
207            self.cross_realm_transform_send_error(cx, rooted_error.handle());
208        }
209
210        result
211    }
212
213    /// <https://streams.spec.whatwg.org/#abstract-opdef-packandpostmessage>
214    pub(crate) fn pack_and_post_message(
215        &self,
216        cx: &mut JSContext,
217        type_: &str,
218        value: HandleValue,
219    ) -> ErrorResult {
220        // Let message be OrdinaryObjectCreate(null).
221        rooted!(&in(cx) let mut message = JS_NewObject(cx, None));
222        rooted!(&in(cx) let mut type_string = UndefinedValue());
223        type_.to_jsval(cx, type_string.handle_mut());
224
225        // Perform ! CreateDataProperty(message, "type", type).
226        set_dictionary_property(cx, message.handle(), c"type", type_string.handle())
227            .expect("Setting the message type should not fail.");
228
229        // Perform ! CreateDataProperty(message, "value", value).
230        set_dictionary_property(cx, message.handle(), c"value", value)
231            .expect("Setting the message value should not fail.");
232
233        // Let targetPort be the port with which port is entangled, if any; otherwise let it be null.
234        // Done in `global.post_messageport_msg`.
235
236        // Let options be «[ "transfer" → « » ]».
237        auto_root!(&in(cx) let transfer = Vec::<*mut JSObject>::new());
238
239        // Run the message port post message steps providing targetPort, message, and options.
240        rooted!(&in(cx) let mut message_val = UndefinedValue());
241        message.to_jsval(cx, message_val.handle_mut());
242        self.post_message_impl(cx, message_val.handle(), transfer)
243    }
244}
245
246impl Transferable for MessagePort {
247    type Index = MessagePortIndex;
248    type Data = MessagePortImpl;
249
250    /// <https://html.spec.whatwg.org/multipage/#message-ports:transfer-steps>
251    fn transfer(
252        &self,
253        _cx: &mut js::context::JSContext,
254    ) -> Fallible<(MessagePortId, MessagePortImpl)> {
255        // <https://html.spec.whatwg.org/multipage/#structuredserializewithtransfer>
256        // Step 5.2. If transferable has a [[Detached]] internal slot and
257        // transferable.[[Detached]] is true, then throw a "DataCloneError"
258        // DOMException.
259        if self.detached.get() {
260            return Err(Error::DataClone(None));
261        }
262
263        self.detached.set(true);
264        let id = self.message_port_id();
265
266        // 1. Run local transfer logic, and return the object to be transferred.
267        let transferred_port = self.global().mark_port_as_transferred(id);
268
269        Ok((*id, transferred_port))
270    }
271
272    /// <https://html.spec.whatwg.org/multipage/#message-ports:transfer-receiving-steps>
273    fn transfer_receive(
274        cx: &mut js::context::JSContext,
275        owner: &GlobalScope,
276        id: MessagePortId,
277        port_impl: MessagePortImpl,
278    ) -> Result<DomRoot<Self>, ()> {
279        let transferred_port =
280            MessagePort::new_transferred(cx, owner, id, port_impl.entangled_port_id());
281        owner.track_message_port(&transferred_port, Some(port_impl));
282        Ok(transferred_port)
283    }
284
285    fn serialized_storage<'a>(
286        data: StructuredData<'a, '_>,
287    ) -> &'a mut Option<FxHashMap<MessagePortId, Self::Data>> {
288        match data {
289            StructuredData::Reader(r) => &mut r.port_impls,
290            StructuredData::Writer(w) => &mut w.ports,
291        }
292    }
293}
294
295impl MessagePortMethods<crate::DomTypeHolder> for MessagePort {
296    /// <https://html.spec.whatwg.org/multipage/#dom-messageport-postmessage>
297    fn PostMessage(
298        &self,
299        cx: &mut JSContext,
300        message: HandleValue,
301        transfer: CustomAutoRooterGuard<Vec<*mut JSObject>>,
302    ) -> ErrorResult {
303        if self.detached.get() {
304            return Ok(());
305        }
306        self.post_message_impl(cx, message, transfer)
307    }
308
309    /// <https://html.spec.whatwg.org/multipage/#dom-messageport-postmessage>
310    fn PostMessage_(
311        &self,
312        cx: &mut JSContext,
313        message: HandleValue,
314        options: &StructuredSerializeOptions,
315    ) -> ErrorResult {
316        if self.detached.get() {
317            return Ok(());
318        }
319        auto_root!(&in(cx) let guard =
320            options
321                .transfer
322                .iter()
323                .map(|js| js.get())
324                .collect::<Vec<_>>());
325        self.post_message_impl(cx, message, guard)
326    }
327
328    /// <https://html.spec.whatwg.org/multipage/#dom-messageport-start>
329    fn Start(&self, cx: &mut JSContext) {
330        if self.detached.get() {
331            return;
332        }
333        self.global().start_message_port(cx, self.message_port_id());
334    }
335
336    /// <https://html.spec.whatwg.org/multipage/#dom-messageport-close>
337    fn Close(&self, cx: &mut JSContext) {
338        // Set this's [[Detached]] internal slot value to true.
339        self.detached.set(true);
340
341        let global = self.global();
342        global.close_message_port(self.message_port_id());
343
344        // If this is entangled, disentangle it.
345        global.disentangle_port(cx, self);
346    }
347
348    /// <https://html.spec.whatwg.org/multipage/#handler-messageport-onmessage>
349    fn GetOnmessage(&self, cx: &mut JSContext) -> Option<RootedCallback<EventHandlerNonNull>> {
350        if self.detached.get() {
351            return None;
352        }
353        let eventtarget = self.upcast::<EventTarget>();
354        eventtarget.get_event_handler_common(cx, "message")
355    }
356
357    /// <https://html.spec.whatwg.org/multipage/#handler-messageport-onmessage>
358    fn SetOnmessage(
359        &self,
360        cx: &mut JSContext,
361        listener: Option<RootedCallback<EventHandlerNonNull>>,
362    ) {
363        if self.detached.get() {
364            return;
365        }
366        self.set_onmessage(cx, listener);
367        // Note: we cannot use the event_handler macro, due to the need to start the port.
368        self.global().start_message_port(cx, self.message_port_id());
369    }
370
371    // <https://html.spec.whatwg.org/multipage/#handler-messageport-onmessageerror>
372    event_handler!(messageerror, GetOnmessageerror, SetOnmessageerror);
373
374    // <https://html.spec.whatwg.org/multipage/#handler-messageport-onclose>
375    event_handler!(close, GetOnclose, SetOnclose);
376}
script/dom/globalscope/messageport.rs

script/dom/globalscope/
messageport.rs
