Replace g_assert with error handling

[songgot]

Release builds often define the compile option -DG_DISABLE_ASSERT for performance optimization. When this option is enabled, the g_assert(condition) macro is replaced by a no-op by the preprocessor.

[jaeyun-jung]

if (g_nns_is_initialized) {
  data_path = g_files_dir;
} else {
  _ml_loge ("NNStreamer native library is not initialized.");
}

[songgot]

Thank you. And I wll add const.

 const char *data_path = NULL;

[jaeyun-jung]

You called nns_destroy_pipe_info() before creating all params (e.g., pipe_info->cls tensors_data_cls_info tensors_info_cls_info).
This causes null-ptr exception.
I suggest just removing this line, handling all error case is too complex.

[songgot]

Okay, I will fixe code like below.

pipe_info = g_new0 (pipeline_info_s, 1);
  g_return_val_if_fail (pipe_info != NULL, NULL);

  (*env)->GetJavaVM (env, &pipe_info->jvm);
  if (!pipe_info->jvm) {
    _ml_loge ("Failed to get Java VM.");
    g_free (pipe_info);
    return NULL;
  }

  pipe_info->pipeline_type = type;
  pipe_info->pipeline_handle = handle;
  pipe_info->element_handles =
      g_hash_table_new_full (g_str_hash, g_str_equal, g_free,
      nns_free_element_data);
  g_mutex_init (&pipe_info->lock);
  pthread_key_create (&pipe_info->jni_env, NULL);