Main thread lock refactoring (#367)

Use slim main thread locking function for macOS instead of a lib.

cmd/worker/main.go

@@ -41,5 +41,5 @@ func run() {
 }
 
 func main() {
-	thread.MainWrapMaybe(run)
+	thread.Wrap(run)
 }

go.mod

@@ -4,7 +4,6 @@ go 1.13
 
 require (
 	github.com/cavaliercoder/grab v1.0.1-0.20201108051000-98a5bfe305ec
-	github.com/faiface/mainthread v0.0.0-20171120011319-8b78f0a41ae3
 	github.com/fsnotify/fsnotify v1.5.1
 	github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6
 	github.com/gofrs/flock v0.8.1

go.sum

@@ -60,8 +60,6 @@ github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymF
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
-github.com/faiface/mainthread v0.0.0-20171120011319-8b78f0a41ae3 h1:baVdMKlASEHrj19iqjARrPbaRisD7EuZEVJj6ZMLl1Q=
-github.com/faiface/mainthread v0.0.0-20171120011319-8b78f0a41ae3/go.mod h1:VEPNJUlxl5KdWjDvz6Q1l+rJlxF2i6xqDeGuGAxa87M=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/fsnotify/fsnotify v1.5.1 h1:mZcQUHVQUQWoPXXtuf9yuEXKudkV2sx1E06UadKWpgI=

pkg/emulator/graphics/sdl.go

@@ -62,7 +62,7 @@ func Init(cfg Config) {
 	}
 
 	// In OSX 10.14+ window creation and context creation must happen in the main thread
-	thread.MainMaybe(createWindow)
+	thread.Main(createWindow)
 
 	BindContext()
 
@@ -77,7 +77,7 @@ func Deinit() {
 	log.Printf("[SDL] [OpenGL] deinitialization...")
 	destroyFramebuffer()
 	// In OSX 10.14+ window deletion must happen in the main thread
-	thread.MainMaybe(destroyWindow)
+	thread.Main(destroyWindow)
 	sdl.Quit()
 	log.Printf("[SDL] [OpenGL] deinitialized (%v, %v)", sdl.GetError(), getDriverError())
 }

pkg/emulator/libretro/nanoarch/nanoarch.go

@@ -594,7 +594,7 @@ func toggleMultitap() {
 
 func nanoarchShutdown() {
 	if usesLibCo {
-		thread.MainMaybe(func() {
+		thread.Main(func() {
 			C.bridge_execute(retroUnloadGame)
 			C.bridge_execute(retroDeinit)
 			if video.isGl {
@@ -603,7 +603,7 @@ func nanoarchShutdown() {
 		})
 	} else {
 		if video.isGl {
-			thread.MainMaybe(func() {
+			thread.Main(func() {
 				// running inside a go routine, lock the thread to make sure the OpenGL context stays current
 				runtime.LockOSThread()
 				graphics.BindContext()
@@ -612,7 +612,7 @@ func nanoarchShutdown() {
 		C.bridge_retro_unload_game(retroUnloadGame)
 		C.bridge_retro_deinit(retroDeinit)
 		if video.isGl {
-			thread.MainMaybe(func() {
+			thread.Main(func() {
 				deinitVideo()
 				runtime.UnlockOSThread()
 			})

pkg/thread/mainthread_darwin.go

@@ -0,0 +1,45 @@
+package thread
+
+import (
+	"runtime"
+	"sync"
+)
+
+type fun struct {
+	fn   func()
+	done chan struct{}
+}
+
+var dPool = sync.Pool{New: func() interface{} { return make(chan struct{}) }}
+var fq = make(chan fun, runtime.GOMAXPROCS(0))
+
+func init() {
+	runtime.LockOSThread()
+}
+
+// Run is a wrapper for the main function.
+// Run returns when run (argument) function finishes.
+func Run(run func()) {
+	done := make(chan struct{})
+	go func() {
+		run()
+		done <- struct{}{}
+	}()
+	for {
+		select {
+		case f := <-fq:
+			f.fn()
+			f.done <- struct{}{}
+		case <-done:
+			return
+		}
+	}
+}
+
+// Call queues function f on the main thread and blocks until the function f finishes.
+func Call(f func()) {
+	done := dPool.Get().(chan struct{})
+	defer dPool.Put(done)
+	fq <- fun{fn: f, done: done}
+	<-done
+}

pkg/thread/mainthread_darwin_test.go

@@ -0,0 +1,16 @@
+package thread
+
+import "testing"
+
+func init() {
+	runtime.LockOSThread()
+}
+
+func TestMainThread(t *testing.T) {
+	value := 0
+	fn := func() { value = 1 }
+	Main(fn)
+	if value != 1 {
+		t.Errorf("wrong value %v", value)
+	}
+}

pkg/thread/thread.go

@@ -1,32 +1,7 @@
-// This package used for locking goroutines to
-// the main OS thread.
-// See: https://github.com/golang/go/wiki/LockOSThread
+//go:build !darwin
+// +build !darwin
+
 package thread
 
-import (
-	"runtime"
-
-	"github.com/faiface/mainthread"
-)
-
-var isMacOs = runtime.GOOS == "darwin"
-
-// MainWrapMaybe enables functions to be executed in the main thread.
-// Enabled for macOS only.
-func MainWrapMaybe(f func()) {
-	if isMacOs {
-		mainthread.Run(f)
-	} else {
-		f()
-	}
-}
-
-// MainMaybe calls a function on the main thread.
-// Enabled for macOS only.
-func MainMaybe(f func()) {
-	if isMacOs {
-		mainthread.Call(f)
-	} else {
-		f()
-	}
-}
+func Wrap(f func()) { f() }
+func Main(f func()) { f() }

pkg/thread/thread_darwin.go

@@ -0,0 +1,10 @@
+// This package used for locking goroutines to
+// the main OS thread.
+// See: https://github.com/golang/go/wiki/LockOSThread
+package thread
+
+// Wrap enables functions to be executed in the main thread.
+func Wrap(f func()) { Run(f) }
+
+// Main calls a function on the main thread.
+func Main(f func()) { Call(f) }

pkg/worker/room/room_test.go

@@ -62,7 +62,7 @@ func TestMain(m *testing.M) {
 	flag.StringVar(&outputPath, "outputPath", "./", "Output path for generated files")
 	flag.BoolVar(&autoGlContext, "autoGlContext", false, "Set auto GL context choose for headless machines")
 
-	thread.MainWrapMaybe(func() { os.Exit(m.Run()) })
+	thread.Wrap(func() { os.Exit(m.Run()) })
 }
 
 func TestRoom(t *testing.T) {
@@ -130,7 +130,7 @@ func TestRoomWithGL(t *testing.T) {
 		time.Sleep(2 * time.Second)
 	}
 
-	thread.MainMaybe(run)
+	thread.Main(run)
 }
 
 func TestAllEmulatorRooms(t *testing.T) {

pkg/worker/worker.go

@@ -17,10 +17,7 @@ func New(conf worker.Config) (services service.Group) {
 	mainHandler := NewHandler(conf, httpSrv.Addr)
 	mainHandler.Prepare()
 
-	services.Add(
-		httpSrv,
-		mainHandler,
-	)
+	services.Add(httpSrv, mainHandler)
 	if conf.Worker.Monitoring.IsEnabled() {
 		services.Add(monitoring.New(conf.Worker.Monitoring, httpSrv.GetHost(), "worker"))
 	}