On Thu, Jul 30, 2020 at 9:57 PM Ben Noordhuis <i...@bnoordhuis.nl> wrote:
> On Thu, Jul 30, 2020 at 8:21 PM Adrienne Walker <e...@chromium.org> wrote: > > Is there any way to know from a v8::Value whether serializing it will > have side effects (at all or on particular properties)? > > Apart from checking whether it's primitive (v->IsNullOrUndefined() || > v->IsBoolean() || ...), I believe the answer is 'no' . Non-primitive > values can have getters and getters execute arbitrary code. > > Checking for only simple properties recursively is an option but > probably not faster and you'll need to handle cycles and a ton of edge > cases (what if the property is a pending promise? what if it's a > WeakMap? etc.) > Can I use HasRealNamedProperty/GetRealNamedProperty to see if I can access those properties without side effects and then check if those values are primitive from there? I suspect that most indexeddb keys being provided here are primitive string values inside a single simple object, and so am I trying to figure out how to fast path this case. Is there a way to tell if a property is one of these complicated edge cases that you mention? > The debugger has a "side-effect-free evaluate" mode but that operates > on functions, not values. You could use it to check getters for side > effects (and promises, and...) but the algorithm is conservative (can > report side effects when there are none) and runs in O(n) time > relative to the function's bytecode size. Given the potential performance issues there, this doesn't sound like a plausible approach. The only other thing we thought of was if there was some way to have some sort of observer as a part of serialization that could record the values without having to deserialize again to access. I worry that this might be too invasive to v8's serialization though. -- -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-users/CA%2B1_fV8rAhA8arck6C%2BXoQC%3DaMx1S_cARXGbymiG-%3DCHko3_5Q%40mail.gmail.com.
