X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Futil%2Fser.rs;h=64d59da0d1c23c7712e9ac06e2ab65cf08326d52;hb=e4c6b70e8ee124ad91cbad84e36b5018da2d07a7;hp=7971f35fc97ce6ef0c8ec9c5dba4348cfdce697b;hpb=c86cacd29d72c0af62cfd29d78dcf17a6d8f8c71;p=rust-lightning

diff --git a/lightning/src/util/ser.rs b/lightning/src/util/ser.rs
index 7971f35f..64d59da0 100644
--- a/lightning/src/util/ser.rs
+++ b/lightning/src/util/ser.rs
@@ -199,8 +199,14 @@ pub trait Writeable {
 
 	/// Writes `self` out to a `Vec<u8>`.
 	fn encode(&self) -> Vec<u8> {
-		let mut msg = VecWriter(Vec::new());
+		let len = self.serialized_length();
+		let mut msg = VecWriter(Vec::with_capacity(len));
 		self.write(&mut msg).unwrap();
+		// Note that objects with interior mutability may change size between when we called
+		// serialized_length and when we called write. That's okay, but shouldn't happen during
+		// testing as most of our tests are not threaded.
+		#[cfg(test)]
+		debug_assert_eq!(len, msg.0.len());
 		msg.0
 	}
 
@@ -211,6 +217,7 @@ pub trait Writeable {
 		0u16.write(&mut msg).unwrap();
 		self.write(&mut msg).unwrap();
 		let len = msg.0.len();
+		debug_assert_eq!(len - 2, self.serialized_length());
 		msg.0[..2].copy_from_slice(&(len as u16 - 2).to_be_bytes());
 		msg.0
 	}
@@ -1297,6 +1304,13 @@ impl Hostname {
 		(&self.0).len() as u8
 	}
 }
+
+impl core::fmt::Display for Hostname {
+	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+		write!(f, "{}", self.0)?;
+		Ok(())
+	}
+}
 impl Deref for Hostname {
 	type Target = String;