Remove Transport::nat_traversal and refactor multiaddr. (#1052)

The functionality is available through `Multiaddr::replace`.
What we currently call "nat_traversal" is merley a replacement of an IP
address prefix in a `Multiaddr`, hence it can be done directly on
`Multiaddr` values instead of having to go through a `Transport`.

In addition this PR consolidates changes made to `Multiaddr` in
previous commits which resulted in lots of deprecations. It adds some
more (see below for the complete list of API changes) and removes all
deprecated functionality, requiring a minor version bump.

Here are the changes to `multiaddr` compared to the currently published
version:

1.  Removed `into_bytes` (use `to_vec` instead).
2.  Renamed `to_bytes` to `to_vec`.
3.  Removed `from_bytes` (use the `TryFrom` impl instead).
4.  Added `with_capacity`.
5.  Added `len`.
6.  Removed `as_slice` (use `AsRef` impl instead).
7.  Removed `encapsulate` (use `push` or `with` instead).
8.  Removed `decapsulate` (use `pop` instead).
9.  Renamed `append` to `push`.
10. Added `with`.
11. Added `replace`.
12. Removed `ToMultiaddr` trait (use `TryFrom` instead).

protocols/identify/src/id_transport.rs

@@ -74,12 +74,10 @@ where
         fn(TMuxer) -> MapErr<IdRetriever<TMuxer>, fn(UpgradeError<IoError>) -> Self::Error>
     >;
 
-    #[inline]
     fn listen_on(self, addr: Multiaddr) -> Result<Self::Listener, TransportError<Self::Error>> {
         Err(TransportError::MultiaddrNotSupported(addr))
     }
 
-    #[inline]
     fn dial(self, addr: Multiaddr) -> Result<Self::Dial, TransportError<Self::Error>> {
         // We dial a first time the node.
         let dial = self.transport.dial(addr)
@@ -88,11 +86,6 @@ where
             IdRetriever::new(muxer, IdentifyProtocolConfig).map_err(TransportUpgradeError::Upgrade)
         }))
     }
-
-    #[inline]
-    fn nat_traversal(&self, a: &Multiaddr, b: &Multiaddr) -> Option<Multiaddr> {
-        self.transport.nat_traversal(a, b)
-    }
 }
 
 /// Implementation of `Future` that asks the remote of its `PeerId`.

protocols/identify/src/protocol.rs

@@ -30,6 +30,7 @@ use log::{debug, trace};
 use protobuf::Message as ProtobufMessage;
 use protobuf::parse_from_bytes as protobuf_parse_from_bytes;
 use protobuf::RepeatedField;
+use std::convert::TryFrom;
 use std::io::{Error as IoError, ErrorKind as IoErrorKind};
 use std::iter;
 use tokio_codec::Framed;
@@ -234,7 +235,7 @@ fn parse_proto_msg(msg: BytesMut) -> Result<(IdentifyInfo, Multiaddr), IoError>
             // Turn a `Vec<u8>` into a `Multiaddr`. If something bad happens, turn it into
             // an `IoError`.
             fn bytes_to_multiaddr(bytes: Vec<u8>) -> Result<Multiaddr, IoError> {
-                Multiaddr::try_from_vec(bytes)
+                Multiaddr::try_from(bytes)
                     .map_err(|err| IoError::new(IoErrorKind::InvalidData, err))
             }