From 33c7498f47bc53a57452ae1b405cb5dadea661a3 Mon Sep 17 00:00:00 2001
From: Martin Hoffmann <martin@nlnetlabs.nl>
Date: Thu, 5 Nov 2020 11:45:32 +0100
Subject: [PATCH] Switch Arc<Mutex<Arc<_>>> to ArcSwap<_>.

---
 Cargo.toml         |  1 +
 src/config.rs      |  6 +++---
 src/metrics.rs     | 15 +++++++--------
 src/targets/rtr.rs | 20 +++++++++++---------
 4 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index c9acad0..927b209 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ license = "BSD-3-Clause"
 readme = "README.md"
 
 [dependencies]
+arc-swap	= "0.4.7"
 chrono          = "0.4.11"
 clap            = "2.33"
 crossbeam-utils = "0.7.2"
diff --git a/src/config.rs b/src/config.rs
index eb93652..42e91ae 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -84,13 +84,13 @@ pub struct Source {
     /// The optional path of a config file.
     ///
     /// If this in `None`, the source is an interactive session.
-    path: Option<Arc<String>>,
+    path: Option<Arc<str>>,
 }
 
 impl<'a, T: AsRef<Path>> From<&'a T> for Source {
     fn from(path: &'a T) -> Source {
         Source {
-            path: Some(Arc::new(format!("{}", path.as_ref().display())))
+            path: Some(format!("{}", path.as_ref().display()).into())
         }
     }
 }
@@ -148,7 +148,7 @@ impl<T> Marked<T> {
     /// Formats the mark for displaying.
     pub fn format_mark(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let source = self.source.as_ref().and_then(|source|
-            source.path.as_ref().map(|path| path.as_str())
+            source.path.as_ref()
         );
         match (source, self.pos) {
             (Some(source), Some(pos)) => {
diff --git a/src/metrics.rs b/src/metrics.rs
index 48f1ada..c38ccfd 100644
--- a/src/metrics.rs
+++ b/src/metrics.rs
@@ -1,8 +1,9 @@
 //! Metrics.
 
 use std::{fmt, iter};
-use std::sync::{Arc, Mutex, Weak};
+use std::sync::{Arc, Weak};
 use std::fmt::Write;
+use arc_swap::ArcSwap;
 use clap::{crate_name, crate_version};
 
 
@@ -15,14 +16,12 @@ const PROMETHEUS_PREFIX: &str = "rtrtr";
 
 #[derive(Clone, Default)]
 pub struct Collection {
-    sources: Arc<Mutex<Arc<Vec<RegisteredSource>>>>,
+    sources: ArcSwap<Vec<RegisteredSource>>,
 }
 
 impl Collection {
     pub fn register(&self, name: Arc<str>, source: Weak<dyn Source>) {
-        let mut sources = self.sources.lock().unwrap();
-
-        let old_sources = sources.clone();
+        let old_sources = self.sources.load();
         let mut new_sources = Vec::new();
         for item in old_sources.iter() {
             if item.source.strong_count() > 0 {
@@ -32,11 +31,11 @@ impl Collection {
         new_sources.push(
             RegisteredSource { name, source }
         );
-        *sources = new_sources.into()
+        self.sources.store(new_sources.into())
     }
 
     pub fn assemble(&self, format: OutputFormat) -> String {
-        let sources = self.sources.lock().unwrap().clone();
+        let sources = self.sources.load();
         let mut target = Target::new(format);
         for item in sources.iter() {
             if let Some(source) = item.source.upgrade() {
@@ -50,7 +49,7 @@ impl Collection {
 
 impl fmt::Debug for Collection {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let len = self.sources.lock().unwrap().len();
+        let len = self.sources.load().len();
         write!(f, "Collection({} sources)", len)
     }
 }
diff --git a/src/targets/rtr.rs b/src/targets/rtr.rs
index 564f045..4a65b79 100644
--- a/src/targets/rtr.rs
+++ b/src/targets/rtr.rs
@@ -1,9 +1,10 @@
 /// RTR servers as a target.
 
 use std::cmp;
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 use std::net::SocketAddr;
 use std::net::TcpListener as StdTcpListener;
+use arc_swap::ArcSwap;
 use log::{debug, error};
 use serde_derive::Deserialize;
 use rpki_rtr::payload::Timing;
@@ -73,17 +74,18 @@ impl Tcp {
 
 }
 
+
 //------------ Source --------------------------------------------------------
 
 #[derive(Clone, Default)]
 struct Source {
-    data: Arc<Mutex<Arc<SourceData>>>,
+    data: ArcSwap<SourceData>,
     diff_num: usize,
 }
 
 impl Source {
     fn update(&self, update: payload::Update) {
-        let data = self.data.lock().unwrap().clone();
+        let data = self.data.load();
 
         let new_data = match data.current.as_ref() {
             None => {
@@ -129,7 +131,7 @@ impl Source {
             }
         };
 
-        *self.data.lock().unwrap() = Arc::new(new_data);
+        self.data.store(new_data.into());
     }
 }
 
@@ -138,15 +140,15 @@ impl VrpSource for Source {
     type DiffIter = payload::DiffIter;
 
     fn ready(&self) -> bool {
-        self.data.lock().unwrap().current.is_some()
+        self.data.load().current.is_some()
     }
 
     fn notify(&self) -> State {
-        self.data.lock().unwrap().state
+        self.data.load().state
     }
 
     fn full(&self) -> (State, Self::FullIter) {
-        let this = self.data.lock().unwrap();
+        let this = self.data.load();
         match this.current.as_ref() {
             Some(current) => (this.state, current.clone().into()),
             None => (this.state, Arc::new(payload::Set::default()).into())
@@ -154,7 +156,7 @@ impl VrpSource for Source {
     }
 
     fn diff(&self, state: State) -> Option<(State, Self::DiffIter)> {
-        let this = self.data.lock().unwrap();
+        let this = self.data.load();
         if this.current.is_none() || state.session() != this.state.session() {
             return None
         }
@@ -165,7 +167,7 @@ impl VrpSource for Source {
     }
 
     fn timing(&self) -> Timing {
-        self.data.lock().unwrap().timing
+        self.data.load().timing
     }
 }