From a7820a5879c799f55755928575fe6106b5b216b5 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Sat, 15 Jan 2022 18:58:17 +0400
Subject: [PATCH] hide watchdog behind cgo flag

---
 connmgr.go         | 17 ++++++++---------
 options.go         |  8 --------
 watchdog_cgo.go    | 18 ++++++++++++++++++
 watchdog_no_cgo.go | 16 ++++++++++++++++
 4 files changed, 42 insertions(+), 17 deletions(-)
 create mode 100644 watchdog_cgo.go
 create mode 100644 watchdog_no_cgo.go

diff --git a/connmgr.go b/connmgr.go
index a42c443..9ee5870 100644
--- a/connmgr.go
+++ b/connmgr.go
@@ -13,7 +13,6 @@ import (
 
 	logging "github.com/ipfs/go-log/v2"
 	ma "github.com/multiformats/go-multiaddr"
-	"github.com/raulk/go-watchdog"
 )
 
 var log = logging.Logger("connmgr")
@@ -44,10 +43,10 @@ type BasicConnMgr struct {
 	lastTrimMu sync.RWMutex
 	lastTrim   time.Time
 
-	refCount           sync.WaitGroup
-	ctx                context.Context
-	cancel             func()
-	unregisterWatchdog func()
+	refCount                sync.WaitGroup
+	ctx                     context.Context
+	cancel                  func()
+	unregisterMemoryWatcher func()
 }
 
 var (
@@ -131,9 +130,7 @@ func NewConnManager(low, hi int, opts ...Option) (*BasicConnMgr, error) {
 
 	if cfg.emergencyTrim {
 		// When we're running low on memory, immediately trigger a trim.
-		cm.unregisterWatchdog = watchdog.RegisterPostGCNotifee(cm.memoryEmergency)
-	} else {
-		cm.unregisterWatchdog = func() {}
+		cm.unregisterMemoryWatcher = registerWatchdog(cm.memoryEmergency)
 	}
 
 	decay, _ := NewDecayer(cfg.decayer, cm)
@@ -176,7 +173,9 @@ func (cm *BasicConnMgr) memoryEmergency() {
 
 func (cm *BasicConnMgr) Close() error {
 	cm.cancel()
-	cm.unregisterWatchdog()
+	if cm.unregisterMemoryWatcher != nil {
+		cm.unregisterMemoryWatcher()
+	}
 	if err := cm.decayer.Close(); err != nil {
 		return err
 	}
diff --git a/options.go b/options.go
index d66884c..76b4ef3 100644
--- a/options.go
+++ b/options.go
@@ -51,11 +51,3 @@ func WithSilencePeriod(p time.Duration) Option {
 		return nil
 	}
 }
-
-// WithEmergencyTrim is an option to enable trimming connections on memory emergency.
-func WithEmergencyTrim(enable bool) Option {
-	return func(cfg *config) error {
-		cfg.emergencyTrim = enable
-		return nil
-	}
-}
diff --git a/watchdog_cgo.go b/watchdog_cgo.go
new file mode 100644
index 0000000..b048111
--- /dev/null
+++ b/watchdog_cgo.go
@@ -0,0 +1,18 @@
+//go:build cgo
+// +build cgo
+
+package connmgr
+
+import "github.com/raulk/go-watchdog"
+
+func registerWatchdog(cb func()) (unregister func()) {
+	return watchdog.RegisterPostGCNotifee(cb)
+}
+
+// WithEmergencyTrim is an option to enable trimming connections on memory emergency.
+func WithEmergencyTrim(enable bool) Option {
+	return func(cfg *config) error {
+		cfg.emergencyTrim = enable
+		return nil
+	}
+}
diff --git a/watchdog_no_cgo.go b/watchdog_no_cgo.go
new file mode 100644
index 0000000..fb83c28
--- /dev/null
+++ b/watchdog_no_cgo.go
@@ -0,0 +1,16 @@
+//go:build !cgo
+// +build !cgo
+
+package connmgr
+
+func registerWatchdog(func()) (unregister func()) {
+	return nil
+}
+
+// WithEmergencyTrim is an option to enable trimming connections on memory emergency.
+func WithEmergencyTrim(enable bool) Option {
+	return func(cfg *config) error {
+		log.Warn("platform doesn't support go-watchdog")
+		return nil
+	}
+}