X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Futil%2Fser.rs;h=5b1a86a6a95f27a276f1dc221bd705f57fbf8ed4;hb=fda38196993b22e34ba43f0bb9c94ba842174bf1;hp=e60f133f5e1638c085e4476d706c8bea32193998;hpb=c30dcf183cf13ef3a9938e15668a8f72906f3184;p=rust-lightning

diff --git a/lightning/src/util/ser.rs b/lightning/src/util/ser.rs
index e60f133f..5b1a86a6 100644
--- a/lightning/src/util/ser.rs
+++ b/lightning/src/util/ser.rs
@@ -136,6 +136,13 @@ impl<R: Read> Read for FixedLengthReader<R> {
 	}
 }
 
+impl<R: Read> LengthRead for FixedLengthReader<R> {
+	#[inline]
+	fn total_bytes(&self) -> u64 {
+		self.total_bytes
+	}
+}
+
 /// A Read which tracks whether any bytes have been read at all. This allows us to distinguish
 /// between "EOF reached before we started" and "EOF reached mid-read".
 pub(crate) struct ReadTrackingReader<R: Read> {
@@ -222,6 +229,21 @@ pub trait ReadableArgs<P>
 	fn read<R: Read>(reader: &mut R, params: P) -> Result<Self, DecodeError>;
 }
 
+/// A std::io::Read that also provides the total bytes available to read.
+pub(crate) trait LengthRead: Read {
+	/// The total number of bytes available to read.
+	fn total_bytes(&self) -> u64;
+}
+
+/// A trait that various higher-level rust-lightning types implement allowing them to be read in
+/// from a Read given some additional set of arguments which is required to deserialize, requiring
+/// the implementer to provide the total length of the read.
+pub(crate) trait LengthReadableArgs<P> where Self: Sized
+{
+	/// Reads a Self in from the given LengthRead
+	fn read<R: LengthRead>(reader: &mut R, params: P) -> 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
@@ -246,6 +268,12 @@ 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>);