- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Thu, 6 Mar 2014 18:03:01 +1100
- To: "Robert O'Callahan" <robert@ocallahan.org>
- Cc: Henri Sivonen <hsivonen@hsivonen.fi>, David Dorwin <ddorwin@google.com>, "public-html-media@w3.org" <public-html-media@w3.org>
Hi Rob, Do you also have an opinion on the DataCue issue https://www.w3.org/Bugs/Public/show_bug.cgi?id=24687 ? Feel free to leave it in the bug. Thanks, Silvia. On Thu, Mar 6, 2014 at 8:55 AM, Robert O'Callahan <robert@ocallahan.org> wrote: > On Tue, Mar 4, 2014 at 12:35 AM, Henri Sivonen <hsivonen@hsivonen.fi> wrote: >> >> I object to both MSE and EME introducing a race condition like that. >> IIRC, this issue already came up with Web Audio. CCing roc for the >> details. > > > I think the situation here is different from Web Audio. In Web Audio we had > true races between threads. In this EME case, there is a well-defined time > at which the array contents are used --- when the task scheduled by > "Schedule a task to initialize the session, providing contentType, initData, > and the new object." runs in the HTML5 event loop. Therefore, as far as I > can tell, you don't necessarily need to specify anything here. In David's > original example, the value 9 would always be used. > >> I think the method should act as if it made a copy of the data before >> returning. In practice, it probably makes sense to have some sort of >> copy-on-write mechanism behind the scenes to avoid copying when no one >> is actually writing to the original buffer. > > > In Web Audio we avoided requiring implementations to support copy-on-write > optimization of typed array buffers. We did this by specifying that typed > arrays passed to certain APIs are neutered --- effectively, ownership of the > buffer is transferred to the callee and it's impossible for Web content to > modify that array afterward. Applying that approach to David's example, the > assignment of 9 would fail because the array would have length 0 after being > passed to createSession. > > As far as I know, nothing in the Web platform currently depends on COW > optimization of typed array buffers for efficiency. I'd like to preserve > that if possible. > > Rob > -- > Jtehsauts tshaei dS,o n" Wohfy Mdaon yhoaus eanuttehrotraiitny eovni le > atrhtohu gthot sf oirng iyvoeu rs ihnesa.r"t sS?o Whhei csha iids teoa > stiheer :p atroa lsyazye,d 'mYaonu,r "sGients uapr,e tfaokreg iyvoeunr, > 'm aotr atnod sgaoy ,h o'mGee.t" uTph eann dt hwea lmka'n? gBoutt uIp > waanndt wyeonut thoo mken.o w
Received on Thursday, 6 March 2014 07:03:51 UTC