_ Git - rust-lightning/blob - lightning/src/util/ser.rs

   1 //! A very simple serialization framework which is used to serialize/deserialize messages as well
   2 //! as ChannelsManagers and ChannelMonitors.
   3
   4 use std::result::Result;
   5 use std::io::{Read, Write};
   6 use std::collections::HashMap;
   7 use std::hash::Hash;
   8 use std::sync::Mutex;
   9 use std::cmp;
  10
  11 use secp256k1::Signature;
  12 use secp256k1::key::{PublicKey, SecretKey};
  13 use bitcoin::blockdata::script::Script;
  14 use bitcoin::blockdata::transaction::{OutPoint, Transaction, TxOut};
  15 use bitcoin::consensus;
  16 use bitcoin::consensus::Encodable;
  17 use bitcoin_hashes::sha256d::Hash as Sha256dHash;
  18 use std::marker::Sized;
  19 use ln::msgs::DecodeError;
  20 use ln::channelmanager::{PaymentPreimage, PaymentHash};
  21 use util::byte_utils;
  22
  23 use util::byte_utils::{be64_to_array, be48_to_array, be32_to_array, be16_to_array, slice_to_be16, slice_to_be32, slice_to_be48, slice_to_be64};
  24
  25 const MAX_BUF_SIZE: usize = 64 * 1024;
  26
  27 /// A trait that is similar to std::io::Write but has one extra function which can be used to size
  28 /// buffers being written into.
  29 /// An impl is provided for any type that also impls std::io::Write which simply ignores size
  30 /// hints.
  31 pub trait Writer {
  32         /// Writes the given buf out. See std::io::Write::write_all for more
  33         fn write_all(&mut self, buf: &[u8]) -> Result<(), ::std::io::Error>;
  34         /// Hints that data of the given size is about the be written. This may not always be called
  35         /// prior to data being written and may be safely ignored.
  36         fn size_hint(&mut self, size: usize);
  37 }
  38
  39 impl<W: Write> Writer for W {
  40         #[inline]
  41         fn write_all(&mut self, buf: &[u8]) -> Result<(), ::std::io::Error> {
  42                 <Self as ::std::io::Write>::write_all(self, buf)
  43         }
  44         #[inline]
  45         fn size_hint(&mut self, _size: usize) { }
  46 }
  47
  48 pub(crate) struct WriterWriteAdaptor<'a, W: Writer + 'a>(pub &'a mut W);
  49 impl<'a, W: Writer + 'a> Write for WriterWriteAdaptor<'a, W> {
  50         fn write_all(&mut self, buf: &[u8]) -> Result<(), ::std::io::Error> {
  51                 self.0.write_all(buf)
  52         }
  53         fn write(&mut self, buf: &[u8]) -> Result<usize, ::std::io::Error> {
  54                 self.0.write_all(buf)?;
  55                 Ok(buf.len())
  56         }
  57         fn flush(&mut self) -> Result<(), ::std::io::Error> {
  58                 Ok(())
  59         }
  60 }
  61
  62 pub(crate) struct VecWriter(pub Vec<u8>);
  63 impl Writer for VecWriter {
  64         fn write_all(&mut self, buf: &[u8]) -> Result<(), ::std::io::Error> {
  65                 self.0.extend_from_slice(buf);
  66                 Ok(())
  67         }
  68         fn size_hint(&mut self, size: usize) {
  69                 self.0.reserve_exact(size);
  70         }
  71 }
  72
  73 /// Writer that only tracks the amount of data written - useful if you need to calculate the length
  74 /// of some data when serialized but don't yet need the full data.
  75 pub(crate) struct LengthCalculatingWriter(pub usize);
  76 impl Writer for LengthCalculatingWriter {
  77         #[inline]
  78         fn write_all(&mut self, buf: &[u8]) -> Result<(), ::std::io::Error> {
  79                 self.0 += buf.len();
  80                 Ok(())
  81         }
  82         #[inline]
  83         fn size_hint(&mut self, _size: usize) {}
  84 }
  85
  86 /// Essentially std::io::Take but a bit simpler and with a method to walk the underlying stream
  87 /// forward to ensure we always consume exactly the fixed length specified.
  88 pub(crate) struct FixedLengthReader<R: Read> {
  89         read: R,
  90         bytes_read: u64,
  91         total_bytes: u64,
  92 }
  93 impl<R: Read> FixedLengthReader<R> {
  94         pub fn new(read: R, total_bytes: u64) -> Self {
  95                 Self { read, bytes_read: 0, total_bytes }
  96         }
  97
  98         pub fn bytes_remain(&mut self) -> bool {
  99                 self.bytes_read != self.total_bytes
 100         }
 101
 102         pub fn eat_remaining(&mut self) -> Result<(), DecodeError> {
 103                 ::std::io::copy(self, &mut ::std::io::sink()).unwrap();
 104                 if self.bytes_read != self.total_bytes {
 105                         Err(DecodeError::ShortRead)
 106                 } else {
 107                         Ok(())
 108                 }
 109         }
 110 }
 111 impl<R: Read> Read for FixedLengthReader<R> {
 112         fn read(&mut self, dest: &mut [u8]) -> Result<usize, ::std::io::Error> {
 113                 if self.total_bytes == self.bytes_read {
 114                         Ok(0)
 115                 } else {
 116                         let read_len = cmp::min(dest.len() as u64, self.total_bytes - self.bytes_read);
 117                         match self.read.read(&mut dest[0..(read_len as usize)]) {
 118                                 Ok(v) => {
 119                                         self.bytes_read += v as u64;
 120                                         Ok(v)
 121                                 },
 122                                 Err(e) => Err(e),
 123                         }
 124                 }
 125         }
 126 }
 127
 128 /// A Read which tracks whether any bytes have been read at all. This allows us to distinguish
 129 /// between "EOF reached before we started" and "EOF reached mid-read".
 130 pub(crate) struct ReadTrackingReader<R: Read> {
 131         read: R,
 132         pub have_read: bool,
 133 }
 134 impl<R: Read> ReadTrackingReader<R> {
 135         pub fn new(read: R) -> Self {
 136                 Self { read, have_read: false }
 137         }
 138 }
 139 impl<R: Read> Read for ReadTrackingReader<R> {
 140         fn read(&mut self, dest: &mut [u8]) -> Result<usize, ::std::io::Error> {
 141                 match self.read.read(dest) {
 142                         Ok(0) => Ok(0),
 143                         Ok(len) => {
 144                                 self.have_read = true;
 145                                 Ok(len)
 146                         },
 147                         Err(e) => Err(e),
 148                 }
 149         }
 150 }
 151
 152 /// A trait that various rust-lightning types implement allowing them to be written out to a Writer
 153 pub trait Writeable {
 154         /// Writes self out to the given Writer
 155         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error>;
 156
 157         /// Writes self out to a Vec<u8>
 158         fn encode(&self) -> Vec<u8> {
 159                 let mut msg = VecWriter(Vec::new());
 160                 self.write(&mut msg).unwrap();
 161                 msg.0
 162         }
 163
 164         /// Writes self out to a Vec<u8>
 165         fn encode_with_len(&self) -> Vec<u8> {
 166                 let mut msg = VecWriter(Vec::new());
 167                 0u16.write(&mut msg).unwrap();
 168                 self.write(&mut msg).unwrap();
 169                 let len = msg.0.len();
 170                 msg.0[..2].copy_from_slice(&byte_utils::be16_to_array(len as u16 - 2));
 171                 msg.0
 172         }
 173 }
 174
 175 /// A trait that various rust-lightning types implement allowing them to be read in from a Read
 176 pub trait Readable<R>
 177         where Self: Sized,
 178               R: Read
 179 {
 180         /// Reads a Self in from the given Read
 181         fn read(reader: &mut R) -> Result<Self, DecodeError>;
 182 }
 183
 184 /// A trait that various higher-level rust-lightning types implement allowing them to be read in
 185 /// from a Read given some additional set of arguments which is required to deserialize.
 186 pub trait ReadableArgs<R, P>
 187         where Self: Sized,
 188               R: Read
 189 {
 190         /// Reads a Self in from the given Read
 191         fn read(reader: &mut R, params: P) -> Result<Self, DecodeError>;
 192 }
 193
 194 /// A trait that various rust-lightning types implement allowing them to (maybe) be read in from a Read
 195 pub trait MaybeReadable<R>
 196         where Self: Sized,
 197               R: Read
 198 {
 199         /// Reads a Self in from the given Read
 200         fn read(reader: &mut R) -> Result<Option<Self>, DecodeError>;
 201 }
 202
 203 pub(crate) struct U48(pub u64);
 204 impl Writeable for U48 {
 205         #[inline]
 206         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 207                 writer.write_all(&be48_to_array(self.0))
 208         }
 209 }
 210 impl<R: Read> Readable<R> for U48 {
 211         #[inline]
 212         fn read(reader: &mut R) -> Result<U48, DecodeError> {
 213                 let mut buf = [0; 6];
 214                 reader.read_exact(&mut buf)?;
 215                 Ok(U48(slice_to_be48(&buf)))
 216         }
 217 }
 218
 219 /// Lightning TLV uses a custom variable-length integer called BigSize. It is similar to Bitcoin's
 220 /// variable-length integers except that it is serialized in big-endian instead of little-endian.
 221 ///
 222 /// Like Bitcoin's variable-length integer, it exhibits ambiguity in that certain values can be
 223 /// encoded in several different ways, which we must check for at deserialization-time. Thus, if
 224 /// you're looking for an example of a variable-length integer to use for your own project, move
 225 /// along, this is a rather poor design.
 226 pub(crate) struct BigSize(pub u64);
 227 impl Writeable for BigSize {
 228         #[inline]
 229         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 230                 match self.0 {
 231                         0...0xFC => {
 232                                 (self.0 as u8).write(writer)
 233                         },
 234                         0xFD...0xFFFF => {
 235                                 0xFDu8.write(writer)?;
 236                                 (self.0 as u16).write(writer)
 237                         },
 238                         0x10000...0xFFFFFFFF => {
 239                                 0xFEu8.write(writer)?;
 240                                 (self.0 as u32).write(writer)
 241                         },
 242                         _ => {
 243                                 0xFFu8.write(writer)?;
 244                                 (self.0 as u64).write(writer)
 245                         },
 246                 }
 247         }
 248 }
 249 impl<R: Read> Readable<R> for BigSize {
 250         #[inline]
 251         fn read(reader: &mut R) -> Result<BigSize, DecodeError> {
 252                 let n: u8 = Readable::read(reader)?;
 253                 match n {
 254                         0xFF => {
 255                                 let x: u64 = Readable::read(reader)?;
 256                                 if x < 0x100000000 {
 257                                         Err(DecodeError::InvalidValue)
 258                                 } else {
 259                                         Ok(BigSize(x))
 260                                 }
 261                         }
 262                         0xFE => {
 263                                 let x: u32 = Readable::read(reader)?;
 264                                 if x < 0x10000 {
 265                                         Err(DecodeError::InvalidValue)
 266                                 } else {
 267                                         Ok(BigSize(x as u64))
 268                                 }
 269                         }
 270                         0xFD => {
 271                                 let x: u16 = Readable::read(reader)?;
 272                                 if x < 0xFD {
 273                                         Err(DecodeError::InvalidValue)
 274                                 } else {
 275                                         Ok(BigSize(x as u64))
 276                                 }
 277                         }
 278                         n => Ok(BigSize(n as u64))
 279                 }
 280         }
 281 }
 282
 283 /// In TLV we occasionally send fields which only consist of, or potentially end with, a
 284 /// variable-length integer which is simply truncated by skipping high zero bytes. This type
 285 /// encapsulates such integers implementing Readable/Writeable for them.
 286 #[cfg_attr(test, derive(PartialEq, Debug))]
 287 pub(crate) struct HighZeroBytesDroppedVarInt<T>(pub T);
 288
 289 macro_rules! impl_writeable_primitive {
 290         ($val_type:ty, $meth_write:ident, $len: expr, $meth_read:ident) => {
 291                 impl Writeable for $val_type {
 292                         #[inline]
 293                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 294                                 writer.write_all(&$meth_write(*self))
 295                         }
 296                 }
 297                 impl Writeable for HighZeroBytesDroppedVarInt<$val_type> {
 298                         #[inline]
 299                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 300                                 // Skip any full leading 0 bytes when writing (in BE):
 301                                 writer.write_all(&$meth_write(self.0)[(self.0.leading_zeros()/8) as usize..$len])
 302                         }
 303                 }
 304                 impl<R: Read> Readable<R> for $val_type {
 305                         #[inline]
 306                         fn read(reader: &mut R) -> Result<$val_type, DecodeError> {
 307                                 let mut buf = [0; $len];
 308                                 reader.read_exact(&mut buf)?;
 309                                 Ok($meth_read(&buf))
 310                         }
 311                 }
 312                 impl<R: Read> Readable<R> for HighZeroBytesDroppedVarInt<$val_type> {
 313                         #[inline]
 314                         fn read(reader: &mut R) -> Result<HighZeroBytesDroppedVarInt<$val_type>, DecodeError> {
 315                                 // We need to accept short reads (read_len == 0) as "EOF" and handle them as simply
 316                                 // the high bytes being dropped. To do so, we start reading into the middle of buf
 317                                 // and then convert the appropriate number of bytes with extra high bytes out of
 318                                 // buf.
 319                                 let mut buf = [0; $len*2];
 320                                 let mut read_len = reader.read(&mut buf[$len..])?;
 321                                 let mut total_read_len = read_len;
 322                                 while read_len != 0 && total_read_len != $len {
 323                                         read_len = reader.read(&mut buf[($len + total_read_len)..])?;
 324                                         total_read_len += read_len;
 325                                 }
 326                                 if total_read_len == 0 || buf[$len] != 0 {
 327                                         let first_byte = $len - ($len - total_read_len);
 328                                         Ok(HighZeroBytesDroppedVarInt($meth_read(&buf[first_byte..first_byte + $len])))
 329                                 } else {
 330                                         // If the encoding had extra zero bytes, return a failure even though we know
 331                                         // what they meant (as the TLV test vectors require this)
 332                                         Err(DecodeError::InvalidValue)
 333                                 }
 334                         }
 335                 }
 336         }
 337 }
 338
 339 impl_writeable_primitive!(u64, be64_to_array, 8, slice_to_be64);
 340 impl_writeable_primitive!(u32, be32_to_array, 4, slice_to_be32);
 341 impl_writeable_primitive!(u16, be16_to_array, 2, slice_to_be16);
 342
 343 impl Writeable for u8 {
 344         #[inline]
 345         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 346                 writer.write_all(&[*self])
 347         }
 348 }
 349 impl<R: Read> Readable<R> for u8 {
 350         #[inline]
 351         fn read(reader: &mut R) -> Result<u8, DecodeError> {
 352                 let mut buf = [0; 1];
 353                 reader.read_exact(&mut buf)?;
 354                 Ok(buf[0])
 355         }
 356 }
 357
 358 impl Writeable for bool {
 359         #[inline]
 360         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 361                 writer.write_all(&[if *self {1} else {0}])
 362         }
 363 }
 364 impl<R: Read> Readable<R> for bool {
 365         #[inline]
 366         fn read(reader: &mut R) -> Result<bool, DecodeError> {
 367                 let mut buf = [0; 1];
 368                 reader.read_exact(&mut buf)?;
 369                 if buf[0] != 0 && buf[0] != 1 {
 370                         return Err(DecodeError::InvalidValue);
 371                 }
 372                 Ok(buf[0] == 1)
 373         }
 374 }
 375
 376 // u8 arrays
 377 macro_rules! impl_array {
 378         ( $size:expr ) => (
 379                 impl Writeable for [u8; $size]
 380                 {
 381                         #[inline]
 382                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 383                                 w.write_all(self)
 384                         }
 385                 }
 386
 387                 impl<R: Read> Readable<R> for [u8; $size]
 388                 {
 389                         #[inline]
 390                         fn read(r: &mut R) -> Result<Self, DecodeError> {
 391                                 let mut buf = [0u8; $size];
 392                                 r.read_exact(&mut buf)?;
 393                                 Ok(buf)
 394                         }
 395                 }
 396         );
 397 }
 398
 399 //TODO: performance issue with [u8; size] with impl_array!()
 400 impl_array!(3); // for rgb
 401 impl_array!(4); // for IPv4
 402 impl_array!(10); // for OnionV2
 403 impl_array!(16); // for IPv6
 404 impl_array!(32); // for channel id & hmac
 405 impl_array!(33); // for PublicKey
 406 impl_array!(64); // for Signature
 407 impl_array!(1300); // for OnionPacket.hop_data
 408
 409 // HashMap
 410 impl<K, V> Writeable for HashMap<K, V>
 411         where K: Writeable + Eq + Hash,
 412               V: Writeable
 413 {
 414         #[inline]
 415         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 416         (self.len() as u16).write(w)?;
 417                 for (key, value) in self.iter() {
 418                         key.write(w)?;
 419                         value.write(w)?;
 420                 }
 421                 Ok(())
 422         }
 423 }
 424
 425 impl<R, K, V> Readable<R> for HashMap<K, V>
 426         where R: Read,
 427               K: Readable<R> + Eq + Hash,
 428               V: Readable<R>
 429 {
 430         #[inline]
 431         fn read(r: &mut R) -> Result<Self, DecodeError> {
 432                 let len: u16 = Readable::read(r)?;
 433                 let mut ret = HashMap::with_capacity(len as usize);
 434                 for _ in 0..len {
 435                         ret.insert(K::read(r)?, V::read(r)?);
 436                 }
 437                 Ok(ret)
 438         }
 439 }
 440
 441 // Vectors
 442 impl Writeable for Vec<u8> {
 443         #[inline]
 444         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 445                 (self.len() as u16).write(w)?;
 446                 w.write_all(&self)
 447         }
 448 }
 449
 450 impl<R: Read> Readable<R> for Vec<u8> {
 451         #[inline]
 452         fn read(r: &mut R) -> Result<Self, DecodeError> {
 453                 let len: u16 = Readable::read(r)?;
 454                 let mut ret = Vec::with_capacity(len as usize);
 455                 ret.resize(len as usize, 0);
 456                 r.read_exact(&mut ret)?;
 457                 Ok(ret)
 458         }
 459 }
 460 impl Writeable for Vec<Signature> {
 461         #[inline]
 462         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 463                 (self.len() as u16).write(w)?;
 464                 for e in self.iter() {
 465                         e.write(w)?;
 466                 }
 467                 Ok(())
 468         }
 469 }
 470
 471 impl<R: Read> Readable<R> for Vec<Signature> {
 472         #[inline]
 473         fn read(r: &mut R) -> Result<Self, DecodeError> {
 474                 let len: u16 = Readable::read(r)?;
 475                 let byte_size = (len as usize)
 476                                 .checked_mul(33)
 477                                 .ok_or(DecodeError::BadLengthDescriptor)?;
 478                 if byte_size > MAX_BUF_SIZE {
 479                         return Err(DecodeError::BadLengthDescriptor);
 480                 }
 481                 let mut ret = Vec::with_capacity(len as usize);
 482                 for _ in 0..len { ret.push(Signature::read(r)?); }
 483                 Ok(ret)
 484         }
 485 }
 486
 487 impl Writeable for Script {
 488         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 489                 (self.len() as u16).write(w)?;
 490                 w.write_all(self.as_bytes())
 491         }
 492 }
 493
 494 impl<R: Read> Readable<R> for Script {
 495         fn read(r: &mut R) -> Result<Self, DecodeError> {
 496                 let len = <u16 as Readable<R>>::read(r)? as usize;
 497                 let mut buf = vec![0; len];
 498                 r.read_exact(&mut buf)?;
 499                 Ok(Script::from(buf))
 500         }
 501 }
 502
 503 impl Writeable for PublicKey {
 504         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 505                 self.serialize().write(w)
 506         }
 507 }
 508
 509 impl<R: Read> Readable<R> for PublicKey {
 510         fn read(r: &mut R) -> Result<Self, DecodeError> {
 511                 let buf: [u8; 33] = Readable::read(r)?;
 512                 match PublicKey::from_slice(&buf) {
 513                         Ok(key) => Ok(key),
 514                         Err(_) => return Err(DecodeError::InvalidValue),
 515                 }
 516         }
 517 }
 518
 519 impl Writeable for SecretKey {
 520         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 521                 let mut ser = [0; 32];
 522                 ser.copy_from_slice(&self[..]);
 523                 ser.write(w)
 524         }
 525 }
 526
 527 impl<R: Read> Readable<R> for SecretKey {
 528         fn read(r: &mut R) -> Result<Self, DecodeError> {
 529                 let buf: [u8; 32] = Readable::read(r)?;
 530                 match SecretKey::from_slice(&buf) {
 531                         Ok(key) => Ok(key),
 532                         Err(_) => return Err(DecodeError::InvalidValue),
 533                 }
 534         }
 535 }
 536
 537 impl Writeable for Sha256dHash {
 538         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 539                 w.write_all(&self[..])
 540         }
 541 }
 542
 543 impl<R: Read> Readable<R> for Sha256dHash {
 544         fn read(r: &mut R) -> Result<Self, DecodeError> {
 545                 use bitcoin_hashes::Hash;
 546
 547                 let buf: [u8; 32] = Readable::read(r)?;
 548                 Ok(Sha256dHash::from_slice(&buf[..]).unwrap())
 549         }
 550 }
 551
 552 impl Writeable for Signature {
 553         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 554                 self.serialize_compact().write(w)
 555         }
 556 }
 557
 558 impl<R: Read> Readable<R> for Signature {
 559         fn read(r: &mut R) -> Result<Self, DecodeError> {
 560                 let buf: [u8; 64] = Readable::read(r)?;
 561                 match Signature::from_compact(&buf) {
 562                         Ok(sig) => Ok(sig),
 563                         Err(_) => return Err(DecodeError::InvalidValue),
 564                 }
 565         }
 566 }
 567
 568 impl Writeable for PaymentPreimage {
 569         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 570                 self.0.write(w)
 571         }
 572 }
 573
 574 impl<R: Read> Readable<R> for PaymentPreimage {
 575         fn read(r: &mut R) -> Result<Self, DecodeError> {
 576                 let buf: [u8; 32] = Readable::read(r)?;
 577                 Ok(PaymentPreimage(buf))
 578         }
 579 }
 580
 581 impl Writeable for PaymentHash {
 582         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 583                 self.0.write(w)
 584         }
 585 }
 586
 587 impl<R: Read> Readable<R> for PaymentHash {
 588         fn read(r: &mut R) -> Result<Self, DecodeError> {
 589                 let buf: [u8; 32] = Readable::read(r)?;
 590                 Ok(PaymentHash(buf))
 591         }
 592 }
 593
 594 impl<T: Writeable> Writeable for Option<T> {
 595         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 596                 match *self {
 597                         None => 0u8.write(w)?,
 598                         Some(ref data) => {
 599                                 1u8.write(w)?;
 600                                 data.write(w)?;
 601                         }
 602                 }
 603                 Ok(())
 604         }
 605 }
 606
 607 impl<R, T> Readable<R> for Option<T>
 608         where R: Read,
 609               T: Readable<R>
 610 {
 611         fn read(r: &mut R) -> Result<Self, DecodeError> {
 612                 match <u8 as Readable<R>>::read(r)? {
 613                         0 => Ok(None),
 614                         1 => Ok(Some(Readable::read(r)?)),
 615                         _ => return Err(DecodeError::InvalidValue),
 616                 }
 617         }
 618 }
 619
 620 impl Writeable for OutPoint {
 621         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 622                 self.txid.write(w)?;
 623                 self.vout.write(w)?;
 624                 Ok(())
 625         }
 626 }
 627
 628 impl<R: Read> Readable<R> for OutPoint {
 629         fn read(r: &mut R) -> Result<Self, DecodeError> {
 630                 let txid = Readable::read(r)?;
 631                 let vout = Readable::read(r)?;
 632                 Ok(OutPoint {
 633                         txid,
 634                         vout,
 635                 })
 636         }
 637 }
 638
 639 macro_rules! impl_consensus_ser {
 640         ($bitcoin_type: ty) => {
 641                 impl Writeable for $bitcoin_type {
 642                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 643                                 match self.consensus_encode(WriterWriteAdaptor(writer)) {
 644                                         Ok(_) => Ok(()),
 645                                         Err(consensus::encode::Error::Io(e)) => Err(e),
 646                                         Err(_) => panic!("We shouldn't get a consensus::encode::Error unless our Write generated an std::io::Error"),
 647                                 }
 648                         }
 649                 }
 650
 651                 impl<R: Read> Readable<R> for $bitcoin_type {
 652                         fn read(r: &mut R) -> Result<Self, DecodeError> {
 653                                 match consensus::encode::Decodable::consensus_decode(r) {
 654                                         Ok(t) => Ok(t),
 655                                         Err(consensus::encode::Error::Io(ref e)) if e.kind() == ::std::io::ErrorKind::UnexpectedEof => Err(DecodeError::ShortRead),
 656                                         Err(consensus::encode::Error::Io(e)) => Err(DecodeError::Io(e)),
 657                                         Err(_) => Err(DecodeError::InvalidValue),
 658                                 }
 659                         }
 660                 }
 661         }
 662 }
 663 impl_consensus_ser!(Transaction);
 664 impl_consensus_ser!(TxOut);
 665
 666 impl<R: Read, T: Readable<R>> Readable<R> for Mutex<T> {
 667         fn read(r: &mut R) -> Result<Self, DecodeError> {
 668                 let t: T = Readable::read(r)?;
 669                 Ok(Mutex::new(t))
 670         }
 671 }
 672 impl<T: Writeable> Writeable for Mutex<T> {
 673         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 674                 self.lock().unwrap().write(w)
 675         }
 676 }
 677
 678 impl<R: Read, A: Readable<R>, B: Readable<R>> Readable<R> for (A, B) {
 679         fn read(r: &mut R) -> Result<Self, DecodeError> {
 680                 let a: A = Readable::read(r)?;
 681                 let b: B = Readable::read(r)?;
 682                 Ok((a, b))
 683         }
 684 }
 685 impl<A: Writeable, B: Writeable> Writeable for (A, B) {
 686         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
 687                 self.0.write(w)?;
 688                 self.1.write(w)
 689         }
 690 }