I'm reverting in the meantime. On Fri, Dec 11, 2015 at 11:15 AM, Toon Verwaest <verwa...@chromium.org> wrote:
> If embedders don't want to have multiple Callees instantiated from the > same FunctionTemplate, Jochen's solution works. If that's the case, they > could also just mark the function-template as caching, and "reinstantiate > the template" in the context. That will return the cached function without > needing to install it on data. > > On Fri, Dec 11, 2015 at 10:57 AM Enrico Pertoso <epert...@chromium.org> > wrote: > >> I think Jochen's solution would be better in the long term. Keeping >> Callee() and instantiating a FunctionTemplate if it gets called seems >> slightly more complex. >> >> In the meantime, should I revert the change (marking Callee as deprecated >> or deprecate soon)? >> >> On Friday, December 11, 2015 at 8:48:22 AM UTC+1, Jochen Eisinger wrote: >> >>> One alternative to using Callee for functions you created yourself is >>> specifying the data parameter which is passed via FunctionCallbackInfo::Data >>> >>> Data could be an External that points to a data structure holding a >>> weak Global pointing back at the function. >>> >>> Would that work for you? >>> >>> On Fri, Dec 11, 2015, 8:41 AM Toon Verwaest <verw...@chromium.org> >>> wrote: >>> >> The difference is that FunctionTemplates are (supposedly) unique for the >>>> entire isolate, whereas JSFunctions are instantiated per native context. So >>>> if you use multiple realms (iframes in a browser setting), you'd be getting >>>> multiple Callees (jsfunction) for the same callback (FunctionTemplate). >>>> >>>> Preallocating all of those is expensive memory-wise and in terms of >>>> context-initialization. Getting to all-can-read accessors (jsfunction from >>>> the accessing context rather than the installed accessor) is either >>>> expensive performance-wise while accessing; or makes the memory and >>>> initialization issues even worse. >>>> >>>> My thinking now is that we could hide the cost inside of info.Callee(), >>>> by instantiating the FunctionTemplate in the current (accessing) context if >>>> the value passed in was null or some other sentinel. That makes it slightly >>>> more expensive for regular templates (the null check), and quite a bit more >>>> for lazy instantiated templates that access Callee. The latter should just >>>> not be used in that scenario... >>>> >>>> On Thu, Dec 10, 2015, 23:25 Alex Kodat <alex...@gmail.com> wrote: >>>> >>>>> That makes great sense to me and would be much appreciated. Though >>>>> I'll admit I don't really understand what it means to call a >>>>> FunctionTemplate. I guess for C++ code there really isn't any containing >>>>> JS >>>>> scope so the distinction between Function and FunctionTemplate is kinda >>>>> (largely?) meaningless? >>>>> >>>>> >>>>> On Thursday, December 10, 2015 at 1:25:38 PM UTC-8, Toon Verwaest >>>>> wrote: >>>>> >>>>>> The reasoning behind this change is that in the future we'll have >>>>>> FunctionTemplates that can be called through accessors without even >>>>>> allocating the JSFunction. Registering the last called value isn't >>>>>> possible >>>>>> in that case... >>>>>> >>>>>> Perhaps rather than fully getting rid of the parameter we should >>>>>> change the API to pass undefined if there is no closure. In that case the >>>>>> FunctionTemplate would need to be instantiated manually through the API >>>>>> to >>>>>> get to the callee. >>>>>> >>>>>> Wdyt Enrico? >>>>>> Toon >>>>>> >>>>>> On Thu, Dec 10, 2015, 20:59 Alex Kodat <alex...@gmail.com> wrote: >>>>>> >>>>> Sorry if this would have been more appropriate on v8-dev but just >>>>>>> downloaded the latest and greatest 4.9 commit and discovered that >>>>>>> Callee is >>>>>>> no longer available in FunctionCallBackInfo. While I'm sure there was a >>>>>>> good reason for this, my sample size of one embedder registers one >>>>>>> "ouch". >>>>>>> Dunno if this affects any other embedders but I guess this is a head's >>>>>>> up >>>>>>> in case anyone wants to check. >>>>>>> >>>>>>> I currently use Callee as a convenience when passing around >>>>>>> FunctionCallBackInfo: for adding the function name to a Throw or as >>>>>>> debugging information it's very convenient. Callee is also very useful >>>>>>> in >>>>>>> the common pattern of allowing a constructor to be called without a New >>>>>>> and >>>>>>> invoking it as a constructor under the covers: >>>>>>> args.Callee()->NewInstance(argc, argsForConstructor). >>>>>>> >>>>>>> The former use is easy to work around but painful as I now need to >>>>>>> add an extra parameter to a ton of internal C++ methods. The latter is >>>>>>> more >>>>>>> challenging as I now need to add a persistent reference to all my C++ >>>>>>> constructors. >>>>>>> >>>>>>> I guess I'll just suck it up but if this affects anyone else one way >>>>>>> to help people deal with this would be to keep a weak reference in the >>>>>>> Isolate to last C++ function called that's made available via something >>>>>>> like isolate->LastCallee(). I'd be happy to submit a project to add >>>>>>> such a >>>>>>> call (obviously on purely selfish grounds) but I suspect it would be >>>>>>> (justifiably) rejected if I'm the world's only user of Callee. >>>>>>> >>>>>>> So are there any others out there? >>>>>>> >>>>>>> Thanks >>>>>>> >>>>>>> -- >>>>>>> -- >>>>>>> v8-users mailing list >>>>>>> >>>>>> v8-u...@googlegroups.com >>>>>> >>>>>> >>>>>>> http://groups.google.com/group/v8-users >>>>>>> --- >>>>>>> You received this message because you are subscribed to the Google >>>>>>> Groups "v8-users" group. >>>>>>> >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>> send an email to v8-users+u...@googlegroups.com. >>>>>> >>>>>> >>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>>> >>>>>> -- >>>>> -- >>>>> v8-users mailing list >>>>> v8-u...@googlegroups.com >>>>> http://groups.google.com/group/v8-users >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "v8-users" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to v8-users+u...@googlegroups.com. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> -- >>>> -- >>>> v8-users mailing list >>>> v8-u...@googlegroups.com >>>> http://groups.google.com/group/v8-users >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "v8-users" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to v8-users+u...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >> -- >> v8-users mailing list >> v8-users@googlegroups.com >> http://groups.google.com/group/v8-users >> --- >> You received this message because you are subscribed to the Google Groups >> "v8-users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to v8-users+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > Enrico Pertoso Software Engineer epert...@google.com Google Germany GmbH Dienerstraße 12 80331 München Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Diese E-Mail ist vertraulich. 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