code: static Asset openNonAssetInPathLocked(final String fileName, AccessMode mode,
        final asset_path ap) {
      Asset pAsset = null;
  
        /* look at the filesystem on disk */
      if (ap.type == kFileTypeDirectory) {
        String8 path = new String8(ap.path);
        path.appendPath(fileName);
  
        pAsset = openAssetFromFileLocked(path, mode);
  
        if (pAsset == null) {
                /* try again, this time with ".gz" */
          path.append(".gz");
          pAsset = openAssetFromFileLocked(path, mode);
        }
  
        if (pAsset != null) {
          //printf("FOUND NA '%s' on disk\n", fileName);
          pAsset.setAssetSource(path);
        }
  
        /* look inside the zip file */
      } else {
        String8 path = new String8(fileName);
  
            /* check the appropriate Zip file */
        ZipFileRO pZip = getZipFileLocked(ap);
        if (pZip != null) {
          //printf("GOT zip, checking NA '%s'\n", (final char*) path);
          ZipEntryRO entry = pZip.findEntryByName(path.string());
          if (entry != null) {
            //printf("FOUND NA in Zip file for %s\n", appName ? appName : kAppCommon);
            pAsset = openAssetFromZipLocked(pZip, entry, mode, path);
            pZip.releaseEntry(entry);
          }
        }
  
        if (pAsset != null) {
                /* create a "source" name, for debug/display */
          pAsset.setAssetSource(
              createZipSourceNameLocked(ap.path, new String8(), new String8(fileName)));
        }
      }
  
      return pAsset;
    }
docs: /*
  Open a non-asset file as if it were an asset, searching for it in the
  specified app.
  
  Pass in a null values for "appName" if the common app directory should
  be used.