X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Futil%2Fser.rs;h=cbdb5485e7bd984312c5a139e220835769f8f73b;hb=6775b957bc0e738afff46eb819c69f45410f1843;hp=707ca2b326d0d5720cae5abec48885e443b46a59;hpb=0ecb4b093ac1134cbf06275cc48dd79ef7524774;p=rust-lightning

diff --git a/lightning/src/util/ser.rs b/lightning/src/util/ser.rs
index 707ca2b3..cbdb5485 100644
--- a/lightning/src/util/ser.rs
+++ b/lightning/src/util/ser.rs
@@ -1349,6 +1349,50 @@ impl Readable for Duration {
 	}
 }
 
+/// A wrapper for a `Transaction` which can only be constructed with [`TransactionU16LenLimited::new`]
+/// if the `Transaction`'s consensus-serialized length is <= u16::MAX.
+///
+/// Use [`TransactionU16LenLimited::into_transaction`] to convert into the contained `Transaction`.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct TransactionU16LenLimited(Transaction);
+
+impl TransactionU16LenLimited {
+	/// Constructs a new `TransactionU16LenLimited` from a `Transaction` only if it's consensus-
+	/// serialized length is <= u16::MAX.
+	pub fn new(transaction: Transaction) -> Result<Self, ()> {
+		if transaction.serialized_length() > (u16::MAX as usize) {
+			Err(())
+		} else {
+			Ok(Self(transaction))
+		}
+	}
+
+	/// Consumes this `TransactionU16LenLimited` and returns its contained `Transaction`.
+	pub fn into_transaction(self) -> Transaction {
+		self.0
+	}
+}
+
+impl Writeable for TransactionU16LenLimited {
+	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+		(self.0.serialized_length() as u16).write(w)?;
+		self.0.write(w)
+	}
+}
+
+impl Readable for TransactionU16LenLimited {
+	fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+		let len = <u16 as Readable>::read(r)?;
+		let mut tx_reader = FixedLengthReader::new(r, len as u64);
+		let tx: Transaction = Readable::read(&mut tx_reader)?;
+		if tx_reader.bytes_remain() {
+			Err(DecodeError::BadLengthDescriptor)
+		} else {
+			Ok(Self(tx))
+		}
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use core::convert::TryFrom;