In C++ you can't overload a method with just a different return type. Since making the context explicit instead of hoping that the right one is entered is nice to have, it was a handy way to change the return type.
On Thu, Apr 9, 2015 at 6:25 PM Adam Klein <[email protected]> wrote: > On Fri, Feb 27, 2015 at 2:43 AM, Michael Hablich <[email protected]> > wrote: > >> Hey v8-users, >> >> we're making big changes to the api (again). We've found that our api makes >> it extremely difficult to write exception safe code. >> >> *Reference issue* >> https://code.google.com/p/v8/issues/detail?id=3929 >> >> *Further description* >> Consider the following: >> >> Local<Value> x = some_value; >> s = x.ToString(); >> // in the current context, ToString might throw an exception, run out >> of stack space, whatever... >> // if that happens we just return an empty Local<String> >> s->Anything() // Crash! >> >> There's too much implicit stuff happening here, and it's bad. It's >> especially >> bad if you use threads and rely on TerminateExecution(), which causes >> lots of v8 function to return empty handles unexpectedly. >> >> To fix this, we will begin adding functions whose signature makes it >> impossible >> to make this mistake and we will deprecate and eventually remove all old >> functions. The new functions will in general come in >> two flavours: >> >> functions like: >> Local<String> ToString(Isolate*); >> >> will become: >> MaybeLocal<String> ToString(Local<Context>); >> >> and functions like: >> double NumberValue(); >> >> will become: >> Maybe<bool> NumberValue(Local<Context>); >> >> The Maybe values ensure at compilation time that the value returned is >> checked >> by the embedder, and the explicit Context makes it clear that a context >> is actually required and that javascript may be executed in that context. >> > > I'm curious about this bit of the design: why was it decided to add an > argument here rather than require a Context to be entered (via > Context::Scope)? > > Rather late to the discussion, I know. Apologies > > - Adam > > >> *Timeline* >> We will add the new API parts gradually to the codebase. When this is >> finished there will be approx. 6 weeks of time where the old and the new >> API will exist side-by-side. This is a good time to make the adjustments in >> your embedding code. After this period the old API will get removed. >> >> We apologize in advance for any trouble this may cause, but we're positive >> that this change will reduce crash rates for practically all v8 >> embedders. >> >> Cheers, >> Michael Hablich >> >> -- >> -- >> v8-users mailing list >> [email protected] >> 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 [email protected]. >> For more options, visit https://groups.google.com/d/optout. >> > -- > -- > v8-users mailing list > [email protected] > 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 [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-users mailing list [email protected] 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
