public synchronized File getSourceFile() {
    if (mSourceFile == null) {
      Preconditions.checkNotNull(mSourceUri.getPath());
      mSourceFile = new File(mSourceUri.getPath());
    }
    return mSourceFile;
  }
Returns whether the use of the cache is enabled for read or write according to given mask.
imagepipeline/src/main/java/com/facebook/imagepipeline/request/ImageRequest.java