in StorageProvider/Application/src/main/java/com/example/android/storageprovider/MyCloudProvider.java [529:545]
private File getFileForDocId(String docId) throws FileNotFoundException {
File target = mBaseDir;
if (docId.equals(ROOT)) {
return target;
}
final int splitIndex = docId.indexOf(':', 1);
if (splitIndex < 0) {
throw new FileNotFoundException("Missing root for " + docId);
} else {
final String path = docId.substring(splitIndex + 1);
target = new File(target, path);
if (!target.exists()) {
throw new FileNotFoundException("Missing file for " + docId + " at " + target);
}
return target;
}
}