Function convert_reader

block/src/qcow/mod.rs:2265–2297

(reader: &mut R, dst_file: RawFile, dst_type: ImageType)

}

fn convert_reader<R>(reader: &mut R, dst_file: RawFile, dst_type: ImageType) -> BlockResult<()>
where
    R: Read + Seek + SeekHole,
{
    let src_size = reader
        .seek(SeekFrom::End(0))
        .map_err(|e| BlockError::new(BlockErrorKind::Io, Error::SeekingFile(e)))?;
    reader
        .rewind()
        .map_err(|e| BlockError::new(BlockErrorKind::Io, Error::SeekingFile(e)))?;

    // Ensure the destination file is empty before writing to it.
    dst_file
        .set_len(0)
        .map_err(|e| BlockError::new(BlockErrorKind::Io, Error::SettingFileSize(e)))?;

    match dst_type {
        ImageType::Qcow2 => {
            let mut dst_writer = QcowFile::new(dst_file, 3, src_size, true)
                .map_err(|e| BlockError::new(BlockErrorKind::Io, e))?;
            convert_reader_writer(reader, &mut dst_writer, src_size)
        }
        ImageType::Raw => {
            let mut dst_writer = dst_file;
            // Set the length of the destination file to convert it into a sparse file
            // of the desired size.
            dst_writer
                .set_len(src_size)
                .map_err(|e| BlockError::new(BlockErrorKind::Io, Error::SettingFileSize(e)))?;
            convert_reader_writer(reader, &mut dst_writer, src_size)
        }
    }
}

/// Copy the contents of a disk image in `src_file` into `dst_file`.
/// The type of `src_file` is automatically detected, and the output file type is