internal/thread: remove Stop and use context.Context instead

internal/thread/thread.go

@@ -14,26 +14,27 @@
 
 package thread
 
+import (
+	"context"
+)
+
 // Thread defines threading behavior in Ebitengine.
 type Thread interface {
 	Call(func())
-	Loop()
-	Stop()
+	Loop(context.Context) error
 }
 
 // OSThread represents an OS thread.
 type OSThread struct {
-	funcs     chan func()
-	done      chan struct{}
-	terminate chan struct{}
+	funcs chan func()
+	done  chan struct{}
 }
 
 // NewOSThread creates a new thread.
 func NewOSThread() *OSThread {
 	return &OSThread{
-		funcs:     make(chan func()),
-		done:      make(chan struct{}),
-		terminate: make(chan struct{}),
+		funcs: make(chan func()),
+		done:  make(chan struct{}),
 	}
 }
 
@@ -42,7 +43,7 @@ func NewOSThread() *OSThread {
 // It is assumed that an OS thread is fixed by runtime.LockOSThread when Loop is called.
 //
 // Loop must be called on the thread.
-func (t *OSThread) Loop() {
+func (t *OSThread) Loop(ctx context.Context) error {
 	for {
 		select {
 		case fn := <-t.funcs:
@@ -53,17 +54,12 @@ func (t *OSThread) Loop() {
 
 				fn()
 			}()
-		case <-t.terminate:
-			return
+		case <-ctx.Done():
+			return ctx.Err()
 		}
 	}
 }
 
-// Stop stops the thread loop.
-func (t *OSThread) Stop() {
-	t.terminate <- struct{}{}
-}
-
 // Call calls f on the thread.
 //
 // Do not call this from the same thread. This would block forever.
@@ -83,10 +79,9 @@ func NewNoopThread() *NoopThread {
 }
 
 // Loop does nothing
-func (t *NoopThread) Loop() {}
+func (t *NoopThread) Loop(ctx context.Context) error {
+	return nil
+}
 
 // Call executes the func immediately
 func (t *NoopThread) Call(f func()) { f() }
-
-// Stop does nothing
-func (t *NoopThread) Stop() {}

internal/ui/run_notsinglethread.go

@@ -17,6 +17,9 @@
 package ui
 
 import (
+	stdcontext "context"
+	"errors"
+
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicscommand"
 	"github.com/hajimehoshi/ebiten/v2/internal/thread"
 )
@@ -36,20 +39,25 @@ func (u *userInterfaceImpl) Run(game Game, options *RunOptions) error {
 		return err
 	}
 
+	ctx, cancel := stdcontext.WithCancel(stdcontext.Background())
+	defer cancel()
+
 	ch := make(chan error, 1)
 	go func() {
 		defer close(ch)
 
 		if err := u.loopGame(); err != nil {
 			ch <- err
+			cancel()
 			return
 		}
 	}()
 
-	defer u.mainThread.Stop()
-	u.mainThread.Loop()
-
-	return <-ch
+	err := u.mainThread.Loop(ctx)
+	if errors.Is(err, stdcontext.Canceled) {
+		return <-ch
+	}
+	return err
 }
 
 // runOnAnotherThreadFromMainThread is called from the main thread, and calls f on a new goroutine (thread).
@@ -68,9 +76,11 @@ func (u *userInterfaceImpl) runOnAnotherThreadFromMainThread(f func()) {
 	u.mainThread = thread.NewOSThread()
 	graphicscommand.SetRenderingThread(u.mainThread)
 
+	ctx, cancel := stdcontext.WithCancel(stdcontext.Background())
+	defer cancel()
 	go func() {
-		defer u.mainThread.Stop()
+		defer cancel()
 		f()
 	}()
-	u.mainThread.Loop()
+	_ = u.mainThread.Loop(ctx)
 }

internal/ui/ui_mobile.go

@@ -17,6 +17,7 @@
 package ui
 
 import (
+	stdcontext "context"
 	"fmt"
 	"runtime/debug"
 	"sync"
@@ -80,12 +81,16 @@ func (u *userInterfaceImpl) Update() error {
 		return err
 	}
 
+	ctx, cancel := stdcontext.WithCancel(stdcontext.Background())
+	defer cancel()
+
 	renderCh <- struct{}{}
 	go func() {
 		<-renderEndCh
-		u.t.Stop()
+		cancel()
 	}()
-	u.t.Loop()
+
+	_ = u.t.Loop(ctx)
 	return nil
 }