Hiya,
I'm trying to perform finalization on sidecar data associated with a
v8 Function (the C++ API) but are having problems getting the GC
finalization callback (and/or a reference over-counting bug
somewhere).
Explanation of what I want do do in pseudo-ish code:
Function createFooFunction() {
impl (args) { -- C++ function implementation -- }
Foo *data = new Foo(); // some "arbitrary" data
return Function(&impl, data);
}
When a Function created using this method is no longer referenced I
want to clean up "data". I've understood that a v8 Persistent handle
is the way to go, but after implementing 3 different approaches and
the "weak callback" still nog getting called (even though I'm
constantly draining V8::IdleNotification), I'm getting a bit hopeless/
desperate.
This is the most minimal implementation which should work (according
to the v8 api guide):
using namespace v8;
static Handle<Value> Handler(const Arguments& args) {
fprintf(stderr, "Handler\n"); fflush(stderr);
return Undefined();
}
static void WeakCallback(Persistent<Value> value, void *data) {
fprintf(stderr, "WeakCallback\n"); fflush(stderr);
}
Local<Function> Create() {
HandleScope scope;
void *data = NULL; // points to something in reality
Local<FunctionTemplate> t =
FunctionTemplate::New(&Handler, External::Wrap(data));
Local<Function> fun = t->GetFunction();
Persistent<Function> phandle = Persistent<Function>::New(fun);
phandle.MakeWeak(data, &WeakCallback);
return scope.Close(fun);
}
~~~
Now the code which call Create:
void createAndCallAFunction() {
HandleScope scope;
Local<Function> fun = Create();
fun->Call(Context::GetCurrent()->Global(), 0, NULL);
}
...
createAndCallAFunction();
while (V8::IdleNotification()) {};
...
The "Handler" gets called as expected, but "WeakCallback" is never
called.
Any ideas?
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