UploadDataProviders.java 文件源码

/**
 * Uploads an entire file, closing the descriptor when it is no longer needed.
 *
 * @param fd The file descriptor to upload
 * @throws IllegalArgumentException if {@code fd} is not a file.
 * @return A new UploadDataProvider for the given file descriptor
 */
public static UploadDataProvider create(final ParcelFileDescriptor fd) {
    return new FileUploadProvider(new FileChannelProvider() {
        @Override
        public FileChannel getChannel() throws IOException {
            if (fd.getStatSize() != -1) {
                return new ParcelFileDescriptor.AutoCloseInputStream(fd).getChannel();
            } else {
                fd.close();
                throw new IllegalArgumentException("Not a file: " + fd);
            }
        }
    });
}