How to determine whether path is directory

[ancientcc]

In order to determine whether path is directory, I try to use tow method.

 

In Java. Use AssetManager.list(), but it too spend CPU, for example 50ms. and have to give up.

In JNI. Use AAssetManager_openDir, but also too spend CPU, for example 50ms. and have to give up.

Is there an effective method to determine path is directory?