Method update_header

block/src/vhdx/vhdx_header.rs:160–200

Creates and returns new updated header from the provided current header

(
        f: &mut File,
        current_header: &Header,
        change_data_guid: bool,
        mut file_write_guid: u128,
        start: u64,
    )

    /// Creates and returns new updated header from the provided current header
    fn update_header(
        f: &mut File,
        current_header: &Header,
        change_data_guid: bool,
        mut file_write_guid: u128,
        start: u64,
    ) -> Result<Header> {
        let mut buffer = [0u8; HEADER_SIZE as usize];
        let mut data_write_guid = current_header.data_write_guid;

        if change_data_guid {
            data_write_guid = Uuid::new_v4().as_u128();
        }

        if file_write_guid == 0 {
            file_write_guid = current_header.file_write_guid;
        }

        let mut new_header = Header {
            signature: current_header.signature,
            checksum: 0,
            sequence_number: current_header.sequence_number + 1,
            file_write_guid,
            data_write_guid,
            log_guid: current_header.log_guid,
            log_version: current_header.log_version,
            version: current_header.version,
            log_length: current_header.log_length,
            log_offset: current_header.log_offset,
        };

        new_header.write_to_buffer(&mut buffer);
        new_header.checksum = calculate_checksum(&mut buffer, size_of::<u32>());
        new_header.write_to_buffer(&mut buffer);

        f.seek(SeekFrom::Start(start))
            .map_err(VhdxHeaderError::SeekHeader)?;
        f.write(&buffer).map_err(VhdxHeaderError::WriteHeader)?;

        Ok(new_header)
    }
}

#[repr(C, packed)]