X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Futil%2Fser.rs;h=ecf85839a5a8e19ebfed3f8e87b8b5832427e4a5;hb=28c9b56113ff1ebb1b505a2c979c55c1626aa06b;hp=d26be4c9ef7a354873cd8c431419b5f1e72bc9e7;hpb=dcc445fa85e3dd85797d2cab35276f13a0f56184;p=rust-lightning

diff --git a/lightning/src/util/ser.rs b/lightning/src/util/ser.rs
index d26be4c9..ecf85839 100644
--- a/lightning/src/util/ser.rs
+++ b/lightning/src/util/ser.rs
@@ -244,6 +244,14 @@ pub(crate) trait LengthReadableArgs<P> where Self: Sized
 	fn read<R: LengthRead>(reader: &mut R, params: P) -> Result<Self, DecodeError>;
 }
 
+/// A trait that various higher-level rust-lightning types implement allowing them to be read in
+/// from a Read, requiring the implementer to provide the total length of the read.
+pub(crate) trait LengthReadable where Self: Sized
+{
+	/// Reads a Self in from the given LengthRead
+	fn read<R: LengthRead>(reader: &mut R) -> Result<Self, DecodeError>;
+}
+
 /// A trait that various rust-lightning types implement allowing them to (maybe) be read in from a Read
 ///
 /// (C-not exported) as we only export serialization to/from byte arrays instead
@@ -268,6 +276,12 @@ impl<T: Readable> Readable for OptionDeserWrapper<T> {
 		Ok(Self(Some(Readable::read(reader)?)))
 	}
 }
+/// When handling default_values, we want to map the default-value T directly
+/// to a OptionDeserWrapper<T> in a way that works for `field: T = t;` as
+/// well. Thus, we assume `Into<T> for T` does nothing and use that.
+impl<T: Readable> From<T> for OptionDeserWrapper<T> {
+	fn from(t: T) -> OptionDeserWrapper<T> { OptionDeserWrapper(Some(t)) }
+}
 
 /// Wrapper to write each element of a Vec with no length prefix
 pub(crate) struct VecWriteWrapper<'a, T: Writeable>(pub &'a Vec<T>);