From 21239f4136bee8adea200cc21aa5590791ccdcc6 Mon Sep 17 00:00:00 2001
From: Marek Kotewicz <marek.kotewicz@gmail.com>
Date: Thu, 13 Sep 2018 10:16:24 +0200
Subject: [PATCH] net_version caches network_id to avoid redundant aquire of
 sync read lock (#9544)

* net_version caches network_id to avoid redundant aquire of sync read lock, #8746

* use lower_hex display formatting for net_peerCount rpc method
---
 rpc/src/v1/impls/net.rs | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/rpc/src/v1/impls/net.rs b/rpc/src/v1/impls/net.rs
index 74521d813..e86bd253f 100644
--- a/rpc/src/v1/impls/net.rs
+++ b/rpc/src/v1/impls/net.rs
@@ -22,7 +22,12 @@ use v1::traits::Net;
 
 /// Net rpc implementation.
 pub struct NetClient<S: ?Sized> {
-	sync: Arc<S>
+	sync: Arc<S>,
+	/// Cached `network_id`.
+	///
+	/// We cache it to avoid redundant aquire of sync read lock.
+	/// https://github.com/paritytech/parity-ethereum/issues/8746
+	network_id: u64,
 }
 
 impl<S: ?Sized> NetClient<S> where S: SyncProvider {
@@ -30,17 +35,18 @@ impl<S: ?Sized> NetClient<S> where S: SyncProvider {
 	pub fn new(sync: &Arc<S>) -> Self {
 		NetClient {
 			sync: sync.clone(),
+			network_id: sync.status().network_id,
 		}
 	}
 }
 
 impl<S: ?Sized> Net for NetClient<S> where S: SyncProvider + 'static {
 	fn version(&self) -> Result<String> {
-		Ok(format!("{}", self.sync.status().network_id).to_owned())
+		Ok(format!("{}", self.network_id))
 	}
 
 	fn peer_count(&self) -> Result<String> {
-		Ok(format!("0x{:x}", self.sync.status().num_peers as u64).to_owned())
+		Ok(format!("{:#x}", self.sync.status().num_peers as u64))
 	}
 
 	fn is_listening(&self) -> Result<bool> {