27955 2015-02-04 07:10:42 +0000 share an immutable object between threads 2016-10-25 09:27:49 +0000 1 1 1 Unclassified HTML WG HTML5 spec unspecified PC All RESOLVED WONTFIX whatwg-resolved P2 enhancement --- 1 charlie651 dave.null annevk arronei bzbarsky mike public-html-admin public-html-wg-issue-tracking public-html-bugzilla oldest_to_newest 117688 0 charlie651 2015-02-04 07:10:42 +0000 "The steps will return a new object of the same type, and will permanently neuter the original object. " It would be nice to have a way to make an arraybuffer available for reading both to a worker thread and to the main thread for reading without duplicating it in memory. Sending it as a message will duplicate it, and transferring it will neuter it making it unavailable to the main thread. If we can make the ArrayBuffer read only, we should be able to share it between the worker and code in the main thread while preserving thread safety. Maybe a syntax like worker.postMessage(message, [transfers], [shares])? 117695 1 bzbarsky 2015-02-04 18:38:22 +0000 This requires JS engines to support threadsafe GC or some other threadsafe form of memory management for the arraybuffer, right? It also requires the readonly bit, which is not so simple post-facto... 117703 2 charlie651 2015-02-05 05:16:55 +0000 Good point that thread safe GC would be required - I don't have a good enough understanding of browser implementations to understand how difficult that would be. Maybe a thread could be required to pass shared objects back to the original thread for them to be released? There is already Object.freeze which works on ArrayBuffer, so i think implementing immutability may not be so much of a challenge. I came across this interesting proposal https://gist.github.com/dherman/5401735 which may be an alternate solution. 117706 3 bzbarsky 2015-02-05 14:21:00 +0000 > There is already Object.freeze which works on ArrayBuffer Object.freeze on an ArrayBuffer doesn't prevent mutation of its data: var buf = new ArrayBuffer(1); var view = new Uint8Array(buf); view[0] = 5; alert(view[0]); Object.freeze(buf); view[0] = 7; var view2 = new Uint8Array(buf); alert(view2[0]); dherman's proposal is a strict superset of yours, looks like; I think it ran into implementation difficulties... 126206 4 arronei 2016-04-27 16:53:38 +0000 HTML5.1 Bugzilla Bug Triage: Incubation needed This bug constitutes a request for a new feature of HTML. The current guidelines [1], rather than track such requests as bugs or issues, please create a proposal outlining the desired behavior, or at least a sketch of what is wanted (much of which is probably contained in this bug), and start the discussion/proposal in the WICG [2]. As your idea gains interest and momentum, it may be brought back into HTML through the Intent to Migrate process [3]. [1] https://github.com/w3c/html#contributing-to-this-repository [2] https://www.w3.org/community/wicg/ [3] https://wicg.github.io/admin/intent-to-migrate.html