// licenses.
macro_rules! encode_tlv {
- ($stream: expr, {$(($type: expr, $field: expr)),*}) => { {
+ ($stream: expr, {$(($type: expr, $field: expr)),*}, {$(($optional_type: expr, $optional_field: expr)),*}) => { {
+ #[allow(unused_imports)]
use util::ser::{BigSize, LengthCalculatingWriter};
+ // Fields must be serialized in order, so we have to potentially switch between optional
+ // fields and normal fields while serializing. Thus, we end up having to loop over the type
+ // counts.
+ // Sadly, while LLVM does appear smart enough to make `max_field` a constant, it appears to
+ // refuse to unroll the loop. If we have enough entries that this is slow we can revisit
+ // this design in the future.
+ #[allow(unused_mut)]
+ let mut max_field: u64 = 0;
$(
- BigSize($type).write($stream)?;
- let mut len_calc = LengthCalculatingWriter(0);
- $field.write(&mut len_calc)?;
- BigSize(len_calc.0 as u64).write($stream)?;
- $field.write($stream)?;
+ if $type >= max_field { max_field = $type + 1; }
)*
+ $(
+ if $optional_type >= max_field { max_field = $optional_type + 1; }
+ )*
+ #[allow(unused_variables)]
+ for i in 0..max_field {
+ $(
+ if i == $type {
+ BigSize($type).write($stream)?;
+ let mut len_calc = LengthCalculatingWriter(0);
+ $field.write(&mut len_calc)?;
+ BigSize(len_calc.0 as u64).write($stream)?;
+ $field.write($stream)?;
+ }
+ )*
+ $(
+ if i == $optional_type {
+ if let Some(ref field) = $optional_field {
+ BigSize($optional_type).write($stream)?;
+ let mut len_calc = LengthCalculatingWriter(0);
+ field.write(&mut len_calc)?;
+ BigSize(len_calc.0 as u64).write($stream)?;
+ field.write($stream)?;
+ }
+ }
+ )*
+ }
} }
}
macro_rules! encode_varint_length_prefixed_tlv {
- ($stream: expr, {$(($type: expr, $field: expr)),*}) => { {
+ ($stream: expr, {$(($type: expr, $field: expr)),*}, {$(($optional_type: expr, $optional_field: expr)),*}) => { {
use util::ser::{BigSize, LengthCalculatingWriter};
+ #[allow(unused_mut)]
let mut len = LengthCalculatingWriter(0);
{
$(
BigSize(field_len.0 as u64).write(&mut len)?;
len.0 += field_len.0;
)*
+ $(
+ if let Some(ref field) = $optional_field {
+ BigSize($optional_type).write(&mut len)?;
+ let mut field_len = LengthCalculatingWriter(0);
+ field.write(&mut field_len)?;
+ BigSize(field_len.0 as u64).write(&mut len)?;
+ len.0 += field_len.0;
+ }
+ )*
}
BigSize(len.0 as u64).write($stream)?;
- encode_tlv!($stream, {
- $(($type, $field)),*
- });
+ encode_tlv!($stream, { $(($type, $field)),* }, { $(($optional_type, $optional_field)),* });
} }
}
}
}
+/// Write out two bytes to indicate the version of an object.
+/// $this_version represents a unique version of a type. Incremented whenever the type's
+/// serialization format has changed or has a new interpretation. Used by a type's
+/// reader to determine how to interpret fields or if it can understand a serialized
+/// object.
+/// $min_version_that_can_read_this is the minimum reader version which can understand this
+/// serialized object. Previous versions will simply err with a
+/// DecodeError::UnknownVersion.
+///
+/// Updates to either $this_version or $min_version_that_can_read_this should be included in
+/// release notes.
+///
+/// Both version fields can be specific to this type of object.
+macro_rules! write_ver_prefix {
+ ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
+ $stream.write_all(&[$this_version; 1])?;
+ $stream.write_all(&[$min_version_that_can_read_this; 1])?;
+ }
+}
+
+/// Writes out a suffix to an object which contains potentially backwards-compatible, optional
+/// fields which old nodes can happily ignore.
+///
+/// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
+/// DecodeError::UnknownRequiredFeature error, with unknown odd fields ignored.
+///
+/// This is the preferred method of adding new fields that old nodes can ignore and still function
+/// correctly.
+macro_rules! write_tlv_fields {
+ ($stream: expr, {$(($type: expr, $field: expr)),*}, {$(($optional_type: expr, $optional_field: expr)),*}) => {
+ encode_varint_length_prefixed_tlv!($stream, {$(($type, $field)),*} , {$(($optional_type, $optional_field)),*});
+ }
+}
+
+/// Reads a prefix added by write_ver_prefix!(), above. Takes the current version of the
+/// serialization logic for this object. This is compared against the
+/// $min_version_that_can_read_this added by write_ver_prefix!().
+macro_rules! read_ver_prefix {
+ ($stream: expr, $this_version: expr) => { {
+ let ver: u8 = Readable::read($stream)?;
+ let min_ver: u8 = Readable::read($stream)?;
+ if min_ver > $this_version {
+ return Err(DecodeError::UnknownVersion);
+ }
+ ver
+ } }
+}
+
+/// Reads a suffix added by write_tlv_fields.
+macro_rules! read_tlv_fields {
+ ($stream: expr, {$(($reqtype: expr, $reqfield: ident)),*}, {$(($type: expr, $field: ident)),*}) => { {
+ let tlv_len = ::util::ser::BigSize::read($stream)?;
+ let mut rd = ::util::ser::FixedLengthReader::new($stream, tlv_len.0);
+ decode_tlv!(&mut rd, {$(($reqtype, $reqfield)),*}, {$(($type, $field)),*});
+ rd.eat_remaining().map_err(|_| DecodeError::ShortRead)?;
+ } }
+}
+
#[cfg(test)]
mod tests {
use std::io::{Cursor, Read};
let mut stream = VecWriter(Vec::new());
stream.0.clear();
- encode_varint_length_prefixed_tlv!(&mut stream, { (1, 1u8) });
+ encode_varint_length_prefixed_tlv!(&mut stream, { (1, 1u8) }, { (42, None::<u64>) });
+ assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
+
+ stream.0.clear();
+ encode_varint_length_prefixed_tlv!(&mut stream, { }, { (1, Some(1u8)) });
assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
stream.0.clear();
- encode_varint_length_prefixed_tlv!(&mut stream, { (4, 0xabcdu16) });
+ encode_varint_length_prefixed_tlv!(&mut stream, { (4, 0xabcdu16) }, { (42, None::<u64>) });
assert_eq!(stream.0, ::hex::decode("040402abcd").unwrap());
stream.0.clear();
- encode_varint_length_prefixed_tlv!(&mut stream, { (0xff, 0xabcdu16) });
+ encode_varint_length_prefixed_tlv!(&mut stream, { (0xff, 0xabcdu16) }, { (42, None::<u64>) });
assert_eq!(stream.0, ::hex::decode("06fd00ff02abcd").unwrap());
stream.0.clear();
- encode_varint_length_prefixed_tlv!(&mut stream, { (0, 1u64), (0xff, HighZeroBytesDroppedVarInt(0u64)) });
+ encode_varint_length_prefixed_tlv!(&mut stream, { (0, 1u64), (0xff, HighZeroBytesDroppedVarInt(0u64)) }, { (42, None::<u64>) });
+ assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
+
+ stream.0.clear();
+ encode_varint_length_prefixed_tlv!(&mut stream, { (0xff, HighZeroBytesDroppedVarInt(0u64)) }, { (0, Some(1u64)) });
assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
Ok(())