Add first_see field to LivePeerInfo (#2724)

Totally nice to have, I personally found it useful. Also could be used
to support FIFO peer list.

p2p/src/handshake.rs

@@ -12,19 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::util::RwLock;
-use std::collections::VecDeque;
-use std::net::{SocketAddr, TcpStream};
-use std::sync::Arc;
-
-use chrono::prelude::*;
-use rand::{thread_rng, Rng};
-
 use crate::core::core::hash::Hash;
 use crate::core::pow::Difficulty;
 use crate::msg::{read_message, write_message, Hand, Shake, Type, PROTOCOL_VERSION, USER_AGENT};
 use crate::peer::Peer;
 use crate::types::{Capabilities, Direction, Error, P2PConfig, PeerAddr, PeerInfo, PeerLiveInfo};
+use crate::util::RwLock;
+use rand::{thread_rng, Rng};
+use std::collections::VecDeque;
+use std::net::{SocketAddr, TcpStream};
+use std::sync::Arc;
 
 /// Local generated nonce for peer connecting.
 /// Used for self-connecting detection (on receiver side),
@@ -105,12 +102,7 @@ impl Handshake {
 			user_agent: shake.user_agent,
 			addr: peer_addr,
 			version: shake.version,
-			live_info: Arc::new(RwLock::new(PeerLiveInfo {
-				total_difficulty: shake.total_difficulty,
-				height: 0,
-				last_seen: Utc::now(),
-				stuck_detector: Utc::now(),
-			})),
+			live_info: Arc::new(RwLock::new(PeerLiveInfo::new(shake.total_difficulty))),
 			direction: Direction::Outbound,
 		};
 
@@ -171,12 +163,7 @@ impl Handshake {
 			user_agent: hand.user_agent,
 			addr: resolve_peer_addr(hand.sender_addr, &conn),
 			version: hand.version,
-			live_info: Arc::new(RwLock::new(PeerLiveInfo {
-				total_difficulty: hand.total_difficulty,
-				height: 0,
-				last_seen: Utc::now(),
-				stuck_detector: Utc::now(),
-			})),
+			live_info: Arc::new(RwLock::new(PeerLiveInfo::new(hand.total_difficulty))),
 			direction: Direction::Inbound,
 		};
 

p2p/src/types.rs

@@ -358,6 +358,7 @@ pub struct PeerLiveInfo {
 	pub height: u64,
 	pub last_seen: DateTime<Utc>,
 	pub stuck_detector: DateTime<Utc>,
+	pub first_seen: DateTime<Utc>,
 }
 
 /// General information about a connected peer that's useful to other modules.
@@ -371,6 +372,18 @@ pub struct PeerInfo {
 	pub live_info: Arc<RwLock<PeerLiveInfo>>,
 }
 
+impl PeerLiveInfo {
+	pub fn new(difficulty: Difficulty) -> PeerLiveInfo {
+		PeerLiveInfo {
+			total_difficulty: difficulty,
+			height: 0,
+			first_seen: Utc::now(),
+			last_seen: Utc::now(),
+			stuck_detector: Utc::now(),
+		}
+	}
+}
+
 impl PeerInfo {
 	/// The current total_difficulty of the peer.
 	pub fn total_difficulty(&self) -> Difficulty {
@@ -391,6 +404,11 @@ impl PeerInfo {
 		self.live_info.read().last_seen
 	}
 
+	/// Time of first_seen for this peer.
+	pub fn first_seen(&self) -> DateTime<Utc> {
+		self.live_info.read().first_seen
+	}
+
 	/// Update the total_difficulty, height and last_seen of the peer.
 	/// Takes a write lock on the live_info.
 	pub fn update(&self, height: u64, total_difficulty: Difficulty) {