Bug 248170 - Listeners to MessagePort Postmessage() receive ArrayBuffer rather than SharedArrayBuffer
Summary: Listeners to MessagePort Postmessage() receive ArrayBuffer rather than Shared...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebCore JavaScript (show other bugs)
Version: Safari 16
Hardware: Mac (Apple Silicon) macOS 13
: P2 Normal
Assignee: Nobody
URL:
Keywords: BrowserCompat, InRadar
Depends on:
Blocks:
 
Reported: 2022-11-21 03:22 PST by Dan S
Modified: 2022-11-28 03:23 PST (History)
4 users (show)

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Description Dan S 2022-11-21 03:22:22 PST 
1. Create a WebWorker that listens for messages using self.onmessage()
2. post the WebWorker a message port from the main thread
3. When the WebWorker receives a message port, listen to messages sent to it with port.OnMessage()
4. from the main thread, post a SharedArrayBuffer on the MessagePort.
5. Upon receiving the posted SharedArrayBuffer, the WebWorker will actually see an ArrayBuffer..

In my application I actually have multiple workers and allow communication between them using SharedArraybuffers that are posted on startup. This all works fine in Chrome, but unfortunately fails because of unwanted SharedArrayBuffer -> ArrayBuffer conversion in Safari.
Comment 1 Dan S 2022-11-21 03:32:32 PST 
Just realised, I didn't mention that the message port posted from the main thread to the web worker was one of the ports created as part of a new MessageChannel.

The main thread then sends SharedArraybuffers using it's port from the MessageChannel and the WebWorker is listening on the port it has been sent.
Comment 2 Radar WebKit Bug Importer 2022-11-28 03:23:20 PST 
<rdar://problem/102711280>