Versioned structs

versioned.rs

macro_rules! cond_with_error(
  ($i:expr, $cond:expr, $submac:ident!( $($args:tt)* )) => (
    {
      if $cond {
        match $submac!($i, $($args)*) {
          nom::IResult::Done(i,o)     => nom::IResult::Done(i, ::std::option::Option::Some(o)),
          nom::IResult::Error(e)      => nom::IResult::Error(e),
          nom::IResult::Incomplete(i) => nom::IResult::Incomplete(i)
        }
      } else {
        nom::IResult::Done($i, ::std::option::Option::None)
      }
    }
  );
  ($i:expr, $cond:expr, $f:expr) => (
    cond!($i, $cond, call!($f));
  );
);

#[derive(RustcEncodable,Debug,Eq,PartialEq)]
pub struct Mosdpgcreate {
    pub epoch: u64,
    pub mkpg: Option<Vec<(pg_t, PgCreateT)>>,
    pub ctimes: Vec<(pg_t, Utime)>,
}

impl<'a> CephPrimitiveVersioned<'a> for Mosdpgcreate {
    fn read_from_wire(input: &'a [u8], head_version: u16, compat_version: u16) -> nom::IResult<&[u8], Self> {
        let head_version = 2;
        let compat_version = 1;

        chain!(input,
		epoch: le_u64 ~
		count: le_u32 ~
		mkpg: cond_with_error!(head_version >=2,
            count!(
                pair!(
                    call!(pg_t::read_from_wire, head_version, compat_version),
                    call!(PgCreateT::read_from_wire, head_version, compat_version)), count as usize)) ~
		count: le_u32 ~
		ctimes: count!(
            pair!(
                call!(pg_t::read_from_wire, head_version, compat_version),
                call!(Utime::read_from_wire, head_version, compat_version)), count as usize) ,
		||{
			Mosdpgcreate{
			epoch: epoch,
			mkpg: mkpg,
			ctimes: ctimes,
		}
	})
    }
    fn write_to_wire(&self) -> Result<Vec<u8>, SerialError> {
        let buffer: Vec<u8> = Vec::new();
        return Ok(buffer);
    }
}