org.robolectric.shadows.ShadowVirtualRefBasePtr Maven / Gradle / Ivy

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package org.robolectric.shadows;

import static android.os.Build.VERSION_CODES.LOLLIPOP;

import com.android.internal.util.VirtualRefBasePtr;
import org.robolectric.annotation.Implementation;
import org.robolectric.annotation.Implements;
import org.robolectric.res.android.NativeObjRegistry;

@Implements(value = VirtualRefBasePtr.class, isInAndroidSdk = false)
public class ShadowVirtualRefBasePtr {
  private static final NativeObjRegistry NATIVE_REGISTRY =
      new NativeObjRegistry<>(RefHolder.class);

  protected static synchronized  long put(T object) {
    return NATIVE_REGISTRY.register(new RefHolder(object));
  }

  protected static synchronized  T get(long nativePtr, Class clazz) {
    return clazz.cast(NATIVE_REGISTRY.getNativeObject(nativePtr).nativeThing);
  }

  @Implementation(minSdk = LOLLIPOP)
  protected static synchronized void nIncStrong(long ptr) {
    if (ptr == 0) {
      return;
    }
    NATIVE_REGISTRY.getNativeObject(ptr).incr();
  }

  @Implementation(minSdk = LOLLIPOP)
  protected static synchronized void nDecStrong(long ptr) {
    if (ptr == 0) {
      return;
    }
    if (NATIVE_REGISTRY.getNativeObject(ptr).decr()) {
      NATIVE_REGISTRY.unregister(ptr);
    }
  }

  private static final class RefHolder {
    private T nativeThing;
    private int refCount;

    private RefHolder(T object) {
      this.nativeThing = object;
    }

    private synchronized void incr() {
      refCount++;
    }

    private synchronized boolean decr() {
      refCount--;
      return refCount == 0;
    }
  }
}