Function array_splice

src/PyListProxyHandler.cc:297–378

}

static bool array_splice(JSContext *cx, unsigned argc, JS::Value *vp) {
  JS::CallArgs args = JS::CallArgsFromVp(argc, vp);

  JS::RootedObject proxy(cx, JS::ToObject(cx, args.thisv()));
  if (!proxy) {
    return false;
  }
  PyObject *self = JS::GetMaybePtrFromReservedSlot<PyObject>(proxy, PyObjectSlot);

  uint64_t selfLength = (uint64_t)PyList_GET_SIZE(self);

  int64_t relativeStart;
  if (!JS::ToInt64(cx, args.get(0), &relativeStart)) {
    return false;
  }

  /* actualStart is the index after which elements will be
      deleted and/or new elements will be added */
  uint64_t actualStart;
  if (relativeStart < 0) {
    actualStart = uint64_t(std::max(double(selfLength) + relativeStart, 0.0));
  } else {
    actualStart = uint64_t(std::min(double(relativeStart), double(selfLength)));
  }

  unsigned int argsLength = args.length();

  /* insertCount is the number of elements being added */
  uint32_t insertCount;
  if (argsLength < 2) {
    insertCount = 0;
  }
  else {
    insertCount = argsLength - 2;
  }

  /* actualDeleteCount is the number of elements being deleted */
  uint64_t actualDeleteCount;
  if (argsLength < 1) {
    actualDeleteCount = 0;
  }
  else if (argsLength < 2) {
    actualDeleteCount = selfLength - actualStart;
  }
  else {
    int64_t deleteCount;
    if (!JS::ToInt64(cx, args.get(1), &deleteCount)) {
      return false;
    }

    actualDeleteCount = uint64_t(std::min(std::max(0.0, double(deleteCount)), double(selfLength - actualStart)));
  }

  // get deleted items for return value
  PyObject *deleted = PyList_GetSlice(self, actualStart, actualStart + actualDeleteCount);
  if (!deleted) {
    return false;
  }