Network sync refactoring (part 7) (#12006)

* Move `MultiaddrWithPeerId` and related parsing functions into `sc-network-common`, remove dependency on `sc-network` from `sc-chain-spec`

* Remove dependency on `sc-network` from `sc-offchain`

* Remove dependency on `sc-network` from `sc-network-gossip`

substrate/client/network/common/src/config.rs

@@ -18,7 +18,8 @@
 
 //! Configuration of the networking layer.
 
-use std::{fmt, str};
+use libp2p::{multiaddr, Multiaddr, PeerId};
+use std::{fmt, str, str::FromStr};
 
 /// Name of a protocol, transmitted on the wire. Should be unique for each chain. Always UTF-8.
 #[derive(Clone, PartialEq, Eq, Hash)]
@@ -42,3 +43,129 @@ impl fmt::Debug for ProtocolId {
 		fmt::Debug::fmt(self.as_ref(), f)
 	}
 }
+
+/// Parses a string address and splits it into Multiaddress and PeerId, if
+/// valid.
+///
+/// # Example
+///
+/// ```
+/// # use libp2p::{Multiaddr, PeerId};
+/// # use sc_network_common::config::parse_str_addr;
+/// let (peer_id, addr) = parse_str_addr(
+/// 	"/ip4/198.51.100.19/tcp/30333/p2p/QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV"
+/// ).unwrap();
+/// assert_eq!(peer_id, "QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".parse::<PeerId>().unwrap());
+/// assert_eq!(addr, "/ip4/198.51.100.19/tcp/30333".parse::<Multiaddr>().unwrap());
+/// ```
+pub fn parse_str_addr(addr_str: &str) -> Result<(PeerId, Multiaddr), ParseErr> {
+	let addr: Multiaddr = addr_str.parse()?;
+	parse_addr(addr)
+}
+
+/// Splits a Multiaddress into a Multiaddress and PeerId.
+pub fn parse_addr(mut addr: Multiaddr) -> Result<(PeerId, Multiaddr), ParseErr> {
+	let who = match addr.pop() {
+		Some(multiaddr::Protocol::P2p(key)) =>
+			PeerId::from_multihash(key).map_err(|_| ParseErr::InvalidPeerId)?,
+		_ => return Err(ParseErr::PeerIdMissing),
+	};
+
+	Ok((who, addr))
+}
+
+/// Address of a node, including its identity.
+///
+/// This struct represents a decoded version of a multiaddress that ends with `/p2p/<peerid>`.
+///
+/// # Example
+///
+/// ```
+/// # use libp2p::{Multiaddr, PeerId};
+/// # use sc_network_common::config::MultiaddrWithPeerId;
+/// let addr: MultiaddrWithPeerId =
+/// 	"/ip4/198.51.100.19/tcp/30333/p2p/QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".parse().unwrap();
+/// assert_eq!(addr.peer_id.to_base58(), "QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV");
+/// assert_eq!(addr.multiaddr.to_string(), "/ip4/198.51.100.19/tcp/30333");
+/// ```
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, PartialEq)]
+#[serde(try_from = "String", into = "String")]
+pub struct MultiaddrWithPeerId {
+	/// Address of the node.
+	pub multiaddr: Multiaddr,
+	/// Its identity.
+	pub peer_id: PeerId,
+}
+
+impl MultiaddrWithPeerId {
+	/// Concatenates the multiaddress and peer ID into one multiaddress containing both.
+	pub fn concat(&self) -> Multiaddr {
+		let proto = multiaddr::Protocol::P2p(From::from(self.peer_id));
+		self.multiaddr.clone().with(proto)
+	}
+}
+
+impl fmt::Display for MultiaddrWithPeerId {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		fmt::Display::fmt(&self.concat(), f)
+	}
+}
+
+impl FromStr for MultiaddrWithPeerId {
+	type Err = ParseErr;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		let (peer_id, multiaddr) = parse_str_addr(s)?;
+		Ok(Self { peer_id, multiaddr })
+	}
+}
+
+impl From<MultiaddrWithPeerId> for String {
+	fn from(ma: MultiaddrWithPeerId) -> String {
+		format!("{}", ma)
+	}
+}
+
+impl TryFrom<String> for MultiaddrWithPeerId {
+	type Error = ParseErr;
+	fn try_from(string: String) -> Result<Self, Self::Error> {
+		string.parse()
+	}
+}
+
+/// Error that can be generated by `parse_str_addr`.
+#[derive(Debug)]
+pub enum ParseErr {
+	/// Error while parsing the multiaddress.
+	MultiaddrParse(multiaddr::Error),
+	/// Multihash of the peer ID is invalid.
+	InvalidPeerId,
+	/// The peer ID is missing from the address.
+	PeerIdMissing,
+}
+
+impl fmt::Display for ParseErr {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			Self::MultiaddrParse(err) => write!(f, "{}", err),
+			Self::InvalidPeerId => write!(f, "Peer id at the end of the address is invalid"),
+			Self::PeerIdMissing => write!(f, "Peer id is missing from the address"),
+		}
+	}
+}
+
+impl std::error::Error for ParseErr {
+	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+		match self {
+			Self::MultiaddrParse(err) => Some(err),
+			Self::InvalidPeerId => None,
+			Self::PeerIdMissing => None,
+		}
+	}
+}
+
+impl From<multiaddr::Error> for ParseErr {
+	fn from(err: multiaddr::Error) -> ParseErr {
+		Self::MultiaddrParse(err)
+	}
+}