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