On Fri, Sep 2, 2016 at 5:42 AM, Zach Bjornson <[email protected]> wrote: > Hello, > > I'm trying to fix some code that creates a wrapped C++ object ("Canvas", > emulating HTMLCanvasElement) with property accessors on the prototype. > Specifically, these assertions should work to reflect browsers' > HTMLCanvasElement API: > > var c = new Canvas(...); > assert(!c.hasOwnProperty("width")); > assert("width" in c); > assert(HTMLCanvasElement.prototype.hasOwnProperty("width")); > > Currently there's an assertion failure (from nan) because the > InternalFieldCount for the PrototypeTemplate is 0. Setting it to 1 fixes > this problem, but without touching the rest of the code, both the > FunctionTemplate and the PrototypeTemplate now have an InternalFieldCount of > 1. Is that the correct situation? I can't find any examples of setting > accessors on prototypes to work from. > > The class in question is this: > https://github.com/Automattic/node-canvas/blob/master/src/Canvas.cc#L30 > (sorry it uses nan's macros and not raw v8 APIs) > and the patch setting the PrototypeTemplate's InternalFieldCount is > https://github.com/Automattic/node-canvas/issues/803#issuecomment-244275154 > > Thanks, > Zach
Nan maintainer here. What you describe sounds correct; setting the internal field count on a template reserves that many slots in instances of that template. -- -- 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.
