Nan构建并循环数组

Question

I'm able to execute a hello world example, but beyond that I'm new to nan and node add-ons .

1. I'm concerned about memory leaks so if I'm causing any please let me know.

2. And how do I push an array onto that out array similar to [].push([0, 1]) . I'm not sure how to do it in the cleanest way possible without creating a new variable to store it - if possible.

3. Also if there's anything else I'm doing that's not best practice please let me know. I've been researching this for a while now.

Here's the code I have so far

  #include <nan.h>

  void Method(const Nan::FunctionCallbackInfo <v8::Value> &info) {

        v8::Local <v8::Context> context = info.GetIsolate()->GetCurrentContext();

        v8::Local <v8::Array> coordinate = v8::Local<v8::Array>::Cast(info[0]);
        unsigned int radius = info[2]->Uint32Value(context).FromJust();

        // Also if creating the array is wasteful this way by giving it the max possible size
        v8::Local <v8::Array> out = Nan::New<v8::Array>(x * y);


        for (int x = -radius; x <= radius; ++x) {
            for (int y = -radius; y <= radius; ++y) {
                if (x * x + y * y <= radius * radius) {
                    // I need to push something like [x +  coordinate->Get(context, 0), y + coordinate->Get(context, 0)]; 
                    out->push_back();
                }
            }
       } 
  }

I was later able to write this.. If anyone can point out if I approached it correctly and/or if there are any memory issues I need to watch out for.

#include <nan.h>

void Method(const Nan::FunctionCallbackInfo <v8::Value> &info) {
    v8::Local <v8::Context> context = info.GetIsolate()->GetCurrentContext();

    v8::Local <v8::Array> coordinates v8::Local<v8::Array>::Cast(info[0]);
    int radius = info[1]->Int32Value(context).FromJust();

    v8::Local <v8::Array> out = Nan::New<v8::Array>();

    int index = 0;
    for (unsigned int i = 0; i < coordinates->Length(); i++) {
        v8::Local <v8::Array> coordinate = v8::Local<v8::Array>::Cast(coordinates->Get(context, i).ToLocalChecked());
        int xArg = coordinate->Get(context, 0).ToLocalChecked()->Int32Value(context).FromJust();
        int yArg = coordinate->Get(context, 1).ToLocalChecked()->Int32Value(context).FromJust();


        for (int xPos = -radius; xPos <= radius; ++xPos) {
            for (int yPos = -radius; yPos <= radius; ++yPos) {
                if (xPos * xPos + yPos * yPos <= radius * radius) {
                    v8::Local <v8::Array> xy = Nan::New<v8::Array>();
                    (void) xy->Set(context, 0, Nan::New(xPos + xArg));
                    (void) xy->Set(context, 1, Nan::New(yPos + yArg));
                    (void) out->Set(context, index++, xy);
                }
            }
        }
    }

    info.GetReturnValue().Set(out);
}

Answer 1

I don't think you have any leaks - in fact there is no implicit memory allocation at all in your code - but in case you need it, I suggest you check the gyp files of my addons for more information on how to build them with asan with g++ or clang . As far as I am concerned, it is a mandatory step when creating Node addons.

https://github.com/mmomtchev/node-gdal-async/blob/master/binding.gyp https://github.com/mmomtchev/exprtk.js/blob/main/binding.gyp

The option is called --enable_asan