From 19b7c7f52afc4d43fa87a8dc9bbdb7ca340c2646 Mon Sep 17 00:00:00 2001
From: wwqgtxx <wwqgtxx@gmail.com>
Date: Fri, 4 Nov 2022 13:11:01 +0800
Subject: [PATCH] Fix: a shared fastSingle.Do() may cause providers untouched
 (#2378)

---
 adapter/outboundgroup/common.go  | 11 ++++++++---
 adapter/outboundgroup/urltest.go |  5 ++++-
 adapter/provider/provider.go     |  6 ++----
 constant/provider/interface.go   |  4 ++--
 4 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/adapter/outboundgroup/common.go b/adapter/outboundgroup/common.go
index 758c7801..b1f05708 100644
--- a/adapter/outboundgroup/common.go
+++ b/adapter/outboundgroup/common.go
@@ -11,14 +11,19 @@ const (
 	defaultGetProxiesDuration = time.Second * 5
 )
 
+func touchProviders(providers []provider.ProxyProvider) {
+	for _, provider := range providers {
+		provider.Touch()
+	}
+}
+
 func getProvidersProxies(providers []provider.ProxyProvider, touch bool) []C.Proxy {
 	proxies := []C.Proxy{}
 	for _, provider := range providers {
 		if touch {
-			proxies = append(proxies, provider.ProxiesWithTouch()...)
-		} else {
-			proxies = append(proxies, provider.Proxies()...)
+			provider.Touch()
 		}
+		proxies = append(proxies, provider.Proxies()...)
 	}
 	return proxies
 }
diff --git a/adapter/outboundgroup/urltest.go b/adapter/outboundgroup/urltest.go
index fd6d6818..79234ecb 100644
--- a/adapter/outboundgroup/urltest.go
+++ b/adapter/outboundgroup/urltest.go
@@ -66,7 +66,7 @@ func (u *URLTest) proxies(touch bool) []C.Proxy {
 }
 
 func (u *URLTest) fast(touch bool) C.Proxy {
-	elm, _, _ := u.fastSingle.Do(func() (any, error) {
+	elm, _, shared := u.fastSingle.Do(func() (any, error) {
 		proxies := u.proxies(touch)
 		fast := proxies[0]
 		min := fast.LastDelay()
@@ -95,6 +95,9 @@ func (u *URLTest) fast(touch bool) C.Proxy {
 
 		return u.fastNode, nil
 	})
+	if shared && touch { // a shared fastSingle.Do() may cause providers untouched, so we touch them again
+		touchProviders(u.providers)
+	}
 
 	return elm.(C.Proxy)
 }
diff --git a/adapter/provider/provider.go b/adapter/provider/provider.go
index 442b4b44..80611ace 100644
--- a/adapter/provider/provider.go
+++ b/adapter/provider/provider.go
@@ -78,9 +78,8 @@ func (pp *proxySetProvider) Proxies() []C.Proxy {
 	return pp.proxies
 }
 
-func (pp *proxySetProvider) ProxiesWithTouch() []C.Proxy {
+func (pp *proxySetProvider) Touch() {
 	pp.healthCheck.touch()
-	return pp.Proxies()
 }
 
 func (pp *proxySetProvider) setProxies(proxies []C.Proxy) {
@@ -205,9 +204,8 @@ func (cp *compatibleProvider) Proxies() []C.Proxy {
 	return cp.proxies
 }
 
-func (cp *compatibleProvider) ProxiesWithTouch() []C.Proxy {
+func (cp *compatibleProvider) Touch() {
 	cp.healthCheck.touch()
-	return cp.Proxies()
 }
 
 func stopCompatibleProvider(pd *CompatibleProvider) {
diff --git a/constant/provider/interface.go b/constant/provider/interface.go
index 53bda7ea..1864f36d 100644
--- a/constant/provider/interface.go
+++ b/constant/provider/interface.go
@@ -66,9 +66,9 @@ type Provider interface {
 type ProxyProvider interface {
 	Provider
 	Proxies() []constant.Proxy
-	// ProxiesWithTouch is used to inform the provider that the proxy is actually being used while getting the list of proxies.
+	// Touch is used to inform the provider that the proxy is actually being used while getting the list of proxies.
 	// Commonly used in DialContext and DialPacketConn
-	ProxiesWithTouch() []constant.Proxy
+	Touch()
 	HealthCheck()
 }