V8 internals
The hooks to access V8 internals—including GC and statistics—are different across the supported versions of V8, therefore NAN provides its own hooks that call the appropriate V8 methods.
NAN_GC_CALLBACK()Nan::AddGCEpilogueCallback()Nan::RemoveGCEpilogueCallback()Nan::AddGCPrologueCallback()Nan::RemoveGCPrologueCallback()Nan::GetHeapStatistics()Nan::SetCounterFunction()Nan::SetCreateHistogramFunction()Nan::SetAddHistogramSampleFunction()Nan::IdleNotification()Nan::LowMemoryNotification()Nan::ContextDisposedNotification()Nan::GetInternalFieldPointer()Nan::SetInternalFieldPointer()Nan::AdjustExternalMemory()
NAN_GC_CALLBACK(callbackname)
Use NAN_GC_CALLBACK to declare your callbacks for Nan::AddGCPrologueCallback() and Nan::AddGCEpilogueCallback(). Your new method receives the arguments v8::GCType type and v8::GCCallbackFlags flags.
static Nan::Persistent<Function> callback;
NAN_GC_CALLBACK(gcPrologueCallback) {
v8::Local<Value> argv[] = { Nan::New("prologue").ToLocalChecked() };
Nan::MakeCallback(Nan::GetCurrentContext()->Global(), Nan::New(callback), 1, argv);
}
NAN_METHOD(Hook) {
callback.Reset(To<Function>(args[0]).ToLocalChecked());
Nan::AddGCPrologueCallback(gcPrologueCallback);
info.GetReturnValue().Set(info.Holder());
}
Nan::AddGCEpilogueCallback()
Signature:
void Nan::AddGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback, v8::GCType gc_type_filter = v8::kGCTypeAll)
Calls V8's AddGCEpilogueCallback().
Nan::RemoveGCEpilogueCallback()
Signature:
void Nan::RemoveGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback)
Calls V8's RemoveGCEpilogueCallback().
Nan::AddGCPrologueCallback()
Signature:
void Nan::AddGCPrologueCallback(v8::Isolate::GCPrologueCallback, v8::GCType gc_type_filter callback)
Calls V8's AddGCPrologueCallback().
Nan::RemoveGCPrologueCallback()
Signature:
void Nan::RemoveGCPrologueCallback(v8::Isolate::GCPrologueCallback callback)
Calls V8's RemoveGCPrologueCallback().
Nan::GetHeapStatistics()
Signature:
void Nan::GetHeapStatistics(v8::HeapStatistics *heap_statistics)
Calls V8's GetHeapStatistics().
Nan::SetCounterFunction()
Signature:
void Nan::SetCounterFunction(v8::CounterLookupCallback cb)
Calls V8's SetCounterFunction().
Nan::SetCreateHistogramFunction()
Signature:
void Nan::SetCreateHistogramFunction(v8::CreateHistogramCallback cb)
Calls V8's SetCreateHistogramFunction().
Nan::SetAddHistogramSampleFunction()
Signature:
void Nan::SetAddHistogramSampleFunction(v8::AddHistogramSampleCallback cb)
Calls V8's SetAddHistogramSampleFunction().
Nan::IdleNotification()
Signature:
bool Nan::IdleNotification(int idle_time_in_ms)
Calls V8's IdleNotification() or IdleNotificationDeadline() depending on V8 version.
Nan::LowMemoryNotification()
Signature:
void Nan::LowMemoryNotification()
Calls V8's LowMemoryNotification().
Nan::ContextDisposedNotification()
Signature:
void Nan::ContextDisposedNotification()
Calls V8's ContextDisposedNotification().
Nan::GetInternalFieldPointer()
Gets a pointer to the internal field with at index from a V8 Object handle.
Signature:
void* Nan::GetInternalFieldPointer(v8::Local<v8::Object> object, int index)
Calls the Object's GetAlignedPointerFromInternalField() or GetPointerFromInternalField() depending on the version of V8.
Nan::SetInternalFieldPointer()
Sets the value of the internal field at index on a V8 Object handle.
Signature:
void Nan::SetInternalFieldPointer(v8::Local<v8::Object> object, int index, void* value)
Calls the Object's SetAlignedPointerInInternalField() or SetPointerInInternalField() depending on the version of V8.
Nan::AdjustExternalMemory()
Signature:
int Nan::AdjustExternalMemory(int bytesChange)
Calls V8's AdjustAmountOfExternalAllocatedMemory().