From 0140881c3851d78f8688215538fbf7466d6684a5 Mon Sep 17 00:00:00 2001
From: debris <marek.kotewicz@gmail.com>
Date: Wed, 28 Sep 2016 16:41:15 +0200
Subject: [PATCH] AcceptHandshake

---
 p2p/src/io/handshake.rs | 67 +++++++++++++++++++++++++++++++++++++++++
 p2p/src/io/mod.rs       |  2 +-
 2 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/p2p/src/io/handshake.rs b/p2p/src/io/handshake.rs
index bc453cf7..79219d78 100644
--- a/p2p/src/io/handshake.rs
+++ b/p2p/src/io/handshake.rs
@@ -9,6 +9,10 @@ fn local_version() -> Message {
 	unimplemented!();
 }
 
+fn verack() -> Message {
+	unimplemented!();
+}
+
 pub struct HandshakeResult {
 	pub version: Version,
 	pub negotiated_version: u32,
@@ -24,16 +28,38 @@ enum HandshakeState<A> {
 	},
 }
 
+enum AcceptHandshakeState<A> {
+	ReceiveVersion(ReadMessage<A>),
+	SendVersion {
+		version: Version,
+		future: WriteMessage<A>,
+	},
+	SendVerack {
+		version: Version,
+		future: WriteMessage<A>,
+	}
+}
+
 pub fn handshake<A>(a: A) -> Handshake<A> where A: io::Write + io::Read {
 	Handshake {
 		state: HandshakeState::SendVersion(write_message(a, &local_version())),
 	}
 }
 
+pub fn accept_handshake<A>(a: A) -> AcceptHandshake<A> where A: io::Write + io::Read {
+	AcceptHandshake {
+		state: AcceptHandshakeState::ReceiveVersion(read_message(a, 0)),
+	}
+}
+
 pub struct Handshake<A> {
 	state: HandshakeState<A>,
 }
 
+pub struct AcceptHandshake<A> {
+	state: AcceptHandshakeState<A>,
+}
+
 impl<A> Future for Handshake<A> where A: io::Read + io::Write {
 	type Item = (A, HandshakeResult);
 	type Error = Error;
@@ -75,3 +101,44 @@ impl<A> Future for Handshake<A> where A: io::Read + io::Write {
 		Ok(Async::NotReady)
 	}
 }
+
+impl<A> Future for AcceptHandshake<A> where A: io::Read + io::Write {
+	type Item = (A, HandshakeResult);
+	type Error = Error;
+
+	fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+		let next = match self.state {
+			AcceptHandshakeState::ReceiveVersion(ref mut future) => {
+				let (stream, message) = try_async!(future.poll());
+				let version = match message.payload {
+					Payload::Version(version) => version,
+					_ => return Err(Error::HandshakeFailed),
+				};
+				AcceptHandshakeState::SendVersion {
+					version: version,
+					future: write_message(stream, &local_version()),
+				}
+			},
+			AcceptHandshakeState::SendVersion { ref version, ref mut future } => {
+				let (stream, _) = try_async!(future.poll());
+				AcceptHandshakeState::SendVerack {
+					version: version.clone(),
+					future: write_message(stream, &verack()),
+				}
+			},
+			AcceptHandshakeState::SendVerack { ref version, ref mut future } => {
+				let (stream, _) = try_async!(future.poll());
+
+				let result = HandshakeResult {
+					version: version.clone(),
+					negotiated_version: cmp::min(VERSION, version.version()),
+				};
+
+				return Ok(Async::Ready((stream, result)));
+			}
+		};
+
+		self.state = next;
+		Ok(Async::NotReady)
+	}
+}
diff --git a/p2p/src/io/mod.rs b/p2p/src/io/mod.rs
index 2a0c4810..72c6dfa7 100644
--- a/p2p/src/io/mod.rs
+++ b/p2p/src/io/mod.rs
@@ -14,7 +14,7 @@ mod read_payload;
 mod write_message;
 
 pub use self::error::Error;
-pub use self::handshake::{handshake, Handshake};
+pub use self::handshake::{handshake, accept_handshake, Handshake, AcceptHandshake};
 pub use self::read_header::{read_header, ReadHeader};
 pub use self::read_message::{read_message, ReadMessage};
 pub use self::read_payload::{read_payload, ReadPayload};