cleanup how we deal with flexible rproof size in ser/deser (#1965)

core/src/ser.rs

@@ -184,10 +184,8 @@ pub trait Reader {
 	fn read_i32(&mut self) -> Result<i32, Error>;
 	/// Read a i64 from the underlying Read
 	fn read_i64(&mut self) -> Result<i64, Error>;
-	/// first before the data bytes.
-	fn read_vec(&mut self) -> Result<Vec<u8>, Error>;
-	/// first before the data bytes limited to max bytes.
-	fn read_limited_vec(&mut self, max: usize) -> Result<Vec<u8>, Error>;
+	/// Read a u64 len prefix followed by that number of exact bytes.
+	fn read_bytes_len_prefix(&mut self) -> Result<Vec<u8>, Error>;
 	/// Read a fixed number of bytes from the underlying reader.
 	fn read_fixed_bytes(&mut self, length: usize) -> Result<Vec<u8>, Error>;
 	/// Consumes a byte from the reader, producing an error if it doesn't have
@@ -281,16 +279,11 @@ impl<'a> Reader for BinReader<'a> {
 		self.source.read_i64::<BigEndian>().map_err(map_io_err)
 	}
 	/// Read a variable size vector from the underlying Read. Expects a usize
-	fn read_vec(&mut self) -> Result<Vec<u8>, Error> {
+	fn read_bytes_len_prefix(&mut self) -> Result<Vec<u8>, Error> {
 		let len = self.read_u64()?;
 		self.read_fixed_bytes(len as usize)
 	}
-	/// Read limited variable size vector from the underlying Read. Expects a
-	/// usize
-	fn read_limited_vec(&mut self, max: usize) -> Result<Vec<u8>, Error> {
-		let len = cmp::min(max, self.read_u64()? as usize);
-		self.read_fixed_bytes(len as usize)
-	}
+	/// Read a fixed number of bytes.
 	fn read_fixed_bytes(&mut self, length: usize) -> Result<Vec<u8>, Error> {
 		// not reading more than 100k in a single read
 		if length > 100000 {
@@ -369,27 +362,30 @@ impl Writeable for RangeProof {
 
 impl Readable for RangeProof {
 	fn read(reader: &mut Reader) -> Result<RangeProof, Error> {
-		let p = reader.read_limited_vec(MAX_PROOF_SIZE)?;
-		let mut a = [0; MAX_PROOF_SIZE];
-		a[..p.len()].clone_from_slice(&p[..]);
+		let len = reader.read_u64()?;
+		let max_len = cmp::min(len as usize, MAX_PROOF_SIZE);
+		let p = reader.read_fixed_bytes(max_len)?;
+		let mut proof = [0; MAX_PROOF_SIZE];
+		proof[..p.len()].clone_from_slice(&p[..]);
 		Ok(RangeProof {
-			proof: a,
-			plen: p.len(),
+			plen: proof.len(),
+			proof,
 		})
 	}
 }
 
 impl FixedLength for RangeProof {
-	const LEN: usize = MAX_PROOF_SIZE + 8;
+	const LEN: usize = 8 // length prefix
+		+ MAX_PROOF_SIZE;
 }
 
 impl PMMRable for RangeProof {}
 
 impl Readable for Signature {
 	fn read(reader: &mut Reader) -> Result<Signature, Error> {
-		let a = reader.read_fixed_bytes(AGG_SIGNATURE_SIZE)?;
-		let mut c = [0; AGG_SIGNATURE_SIZE];
-		c[..AGG_SIGNATURE_SIZE].clone_from_slice(&a[..AGG_SIGNATURE_SIZE]);
+		let a = reader.read_fixed_bytes(Signature::LEN)?;
+		let mut c = [0; Signature::LEN];
+		c[..Signature::LEN].clone_from_slice(&a[..Signature::LEN]);
 		Ok(Signature::from_raw_data(&c).unwrap())
 	}
 }
@@ -400,6 +396,10 @@ impl Writeable for Signature {
 	}
 }
 
+impl FixedLength for Signature {
+	const LEN: usize = AGG_SIGNATURE_SIZE;
+}
+
 /// Utility wrapper for an underlying byte Writer. Defines higher level methods
 /// to write numbers, byte vectors, hashes, etc.
 pub struct BinWriter<'a> {

p2p/src/msg.rs

@@ -362,7 +362,7 @@ impl Readable for Hand {
 		let total_diff = Difficulty::read(reader)?;
 		let sender_addr = SockAddr::read(reader)?;
 		let receiver_addr = SockAddr::read(reader)?;
-		let ua = reader.read_vec()?;
+		let ua = reader.read_bytes_len_prefix()?;
 		let user_agent = String::from_utf8(ua).map_err(|_| ser::Error::CorruptedData)?;
 		let genesis = Hash::read(reader)?;
 		Ok(Hand {
@@ -413,7 +413,7 @@ impl Readable for Shake {
 		let (version, capab) = ser_multiread!(reader, read_u32, read_u32);
 		let capabilities = Capabilities::from_bits_truncate(capab);
 		let total_diff = Difficulty::read(reader)?;
-		let ua = reader.read_vec()?;
+		let ua = reader.read_bytes_len_prefix()?;
 		let user_agent = String::from_utf8(ua).map_err(|_| ser::Error::CorruptedData)?;
 		let genesis = Hash::read(reader)?;
 		Ok(Shake {
@@ -498,7 +498,8 @@ impl Writeable for PeerError {
 
 impl Readable for PeerError {
 	fn read(reader: &mut Reader) -> Result<PeerError, ser::Error> {
-		let (code, msg) = ser_multiread!(reader, read_u32, read_vec);
+		let code = reader.read_u32()?;
+		let msg = reader.read_bytes_len_prefix()?;
 		let message = String::from_utf8(msg).map_err(|_| ser::Error::CorruptedData)?;
 		Ok(PeerError {
 			code: code,

p2p/src/store.rs

@@ -80,8 +80,10 @@ impl Writeable for PeerData {
 impl Readable for PeerData {
 	fn read(reader: &mut Reader) -> Result<PeerData, ser::Error> {
 		let addr = SockAddr::read(reader)?;
-		let (capab, ua, fl, lb, br) =
-			ser_multiread!(reader, read_u32, read_vec, read_u8, read_i64, read_i32);
+		let capab = reader.read_u32()?;
+		let ua = reader.read_bytes_len_prefix()?;
+		let (fl, lb, br) = ser_multiread!(reader, read_u8, read_i64, read_i32);
+
 		let lc = reader.read_i64();
 		// this only works because each PeerData is read in its own vector and this
 		// is the last data element
@@ -90,6 +92,7 @@ impl Readable for PeerData {
 		} else {
 			lc.unwrap()
 		};
+
 		let user_agent = String::from_utf8(ua).map_err(|_| ser::Error::CorruptedData)?;
 		let capabilities = Capabilities::from_bits_truncate(capab);
 		let ban_reason = ReasonForBan::from_i32(br).ok_or(ser::Error::CorruptedData)?;

wallet/src/libwallet/types.rs

@@ -262,7 +262,7 @@ impl ser::Writeable for OutputData {
 
 impl ser::Readable for OutputData {
 	fn read(reader: &mut ser::Reader) -> Result<OutputData, ser::Error> {
-		let data = reader.read_vec()?;
+		let data = reader.read_bytes_len_prefix()?;
 		serde_json::from_slice(&data[..]).map_err(|_| ser::Error::CorruptedData)
 	}
 }
@@ -431,7 +431,7 @@ impl ser::Writeable for Context {
 
 impl ser::Readable for Context {
 	fn read(reader: &mut ser::Reader) -> Result<Context, ser::Error> {
-		let data = reader.read_vec()?;
+		let data = reader.read_bytes_len_prefix()?;
 		serde_json::from_slice(&data[..]).map_err(|_| ser::Error::CorruptedData)
 	}
 }
@@ -615,7 +615,7 @@ impl ser::Writeable for TxLogEntry {
 
 impl ser::Readable for TxLogEntry {
 	fn read(reader: &mut ser::Reader) -> Result<TxLogEntry, ser::Error> {
-		let data = reader.read_vec()?;
+		let data = reader.read_bytes_len_prefix()?;
 		serde_json::from_slice(&data[..]).map_err(|_| ser::Error::CorruptedData)
 	}
 }
@@ -663,7 +663,7 @@ impl ser::Writeable for AcctPathMapping {
 
 impl ser::Readable for AcctPathMapping {
 	fn read(reader: &mut ser::Reader) -> Result<AcctPathMapping, ser::Error> {
-		let data = reader.read_vec()?;
+		let data = reader.read_bytes_len_prefix()?;
 		serde_json::from_slice(&data[..]).map_err(|_| ser::Error::CorruptedData)
 	}
 }