From ebb9cd055f9dfb19fabdcedb506ba78c43cb43dd Mon Sep 17 00:00:00 2001
From: fakeshadow <24548779@qq.com>
Date: Fri, 5 Feb 2021 19:38:11 -0800
Subject: [PATCH] use static dispatch on signal handling. reduce allocation
 (#272)

---
 actix-rt/Cargo.toml         |  4 ++--
 actix-server/src/signals.rs | 40 +++++++++++++++++--------------------
 2 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/actix-rt/Cargo.toml b/actix-rt/Cargo.toml
index f8f3984d..db232090 100644
--- a/actix-rt/Cargo.toml
+++ b/actix-rt/Cargo.toml
@@ -26,8 +26,8 @@ macros = ["actix-macros"]
 actix-macros = { version = "0.2.0", optional = true }
 
 futures-core = { version = "0.3", default-features = false }
-tokio = { version = "1", features = ["rt", "net", "parking_lot", "signal", "sync", "time"] }
+tokio = { version = "1.2", features = ["rt", "net", "parking_lot", "signal", "sync", "time"] }
 
 [dev-dependencies]
-tokio = { version = "1", features = ["full"] }
+tokio = { version = "1.2", features = ["full"] }
 hyper = { version = "0.14", default-features = false, features = ["server", "tcp", "http1"] }
diff --git a/actix-server/src/signals.rs b/actix-server/src/signals.rs
index ea1de47e..0e3cef13 100644
--- a/actix-server/src/signals.rs
+++ b/actix-server/src/signals.rs
@@ -2,8 +2,6 @@ use std::future::Future;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
-use futures_core::future::LocalBoxFuture;
-
 use crate::server::Server;
 
 /// Different types of process signals
@@ -23,9 +21,9 @@ pub(crate) enum Signal {
 pub(crate) struct Signals {
     srv: Server,
     #[cfg(not(unix))]
-    signals: LocalBoxFuture<'static, std::io::Result<()>>,
+    signals: futures_core::future::LocalBoxFuture<'static, std::io::Result<()>>,
     #[cfg(unix)]
-    signals: Vec<(Signal, LocalBoxFuture<'static, ()>)>,
+    signals: Vec<(Signal, actix_rt::signal::unix::Signal)>,
 }
 
 impl Signals {
@@ -48,23 +46,21 @@ impl Signals {
                 (unix::SignalKind::quit(), Signal::Quit),
             ];
 
-            let mut signals = Vec::new();
-
-            for (kind, sig) in sig_map.iter() {
-                match unix::signal(*kind) {
-                    Ok(mut stream) => {
-                        let fut = Box::pin(async move {
-                            let _ = stream.recv().await;
-                        }) as _;
-                        signals.push((*sig, fut));
-                    }
-                    Err(e) => log::error!(
-                        "Can not initialize stream handler for {:?} err: {}",
-                        sig,
-                        e
-                    ),
-                }
-            }
+            let signals = sig_map
+                .iter()
+                .filter_map(|(kind, sig)| {
+                    unix::signal(*kind)
+                        .map(|tokio_sig| (*sig, tokio_sig))
+                        .map_err(|e| {
+                            log::error!(
+                                "Can not initialize stream handler for {:?} err: {}",
+                                sig,
+                                e
+                            )
+                        })
+                        .ok()
+                })
+                .collect::<Vec<_>>();
 
             actix_rt::spawn(Signals { srv, signals });
         }
@@ -86,7 +82,7 @@ impl Future for Signals {
         #[cfg(unix)]
         {
             for (sig, fut) in self.signals.iter_mut() {
-                if fut.as_mut().poll(cx).is_ready() {
+                if Pin::new(fut).poll_recv(cx).is_ready() {
                     let sig = *sig;
                     self.srv.signal(sig);
                     return Poll::Ready(());