fix(examples): gate first present, shutdown order, SIGTERM, timeline cleanup in layer

commit: 1988d1edfc30509bec290f11afdaa2c7f9576c8c
author: brice · 21d ago · 2026-10-01 19:23 UTC
parent: 7c37286
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

1 file · +26 -5

M examples/layer/main.go +26 -5


@@ -19,6 +19,7 @@ import (
19	19		"fmt"
20	20		"os"
21	21		"os/signal"
	22	+	"syscall"
22	23		"time"
23	24
24	25		"github.com/bnema/neferclient"

@@ -30,6 +31,10 @@ import (
30	31		const (
31	32		surfaceW, surfaceH = 240, 90
32	33		buttonColor = "#2060c0"
	34	+
	35	+	// guiMods is the set of modifiers NeferGUI knows. neferclient and NeferGUI
	36	+	// use the same bit order for them, so the plain bits can be copied.
	37	+	guiMods = neferclient.ModShift \| neferclient.ModCtrl \| neferclient.ModAlt \| neferclient.ModSuper
33	38		)
34	39
35	40		type model struct{ count int }

@@ -71,7 +76,7 @@ type app struct {
71	76		func main() {
72	77		frames := flag.Int("frames", 0, "redraw continuously and exit after this many frames (0: run until closed)")
73	78		flag.Parse()
74		-	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
	79	+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
75	80		defer stop()
76	81		if err := run(ctx, *frames); err != nil {
77	82		fmt.Fprintln(os.Stderr, "layer:", err)

@@ -85,11 +90,14 @@ func run(ctx context.Context, frames int) (err error) {
85	90		return fmt.Errorf("connect: %w", err)
86	91		}
87	92		a := &app{conn: conn, frames: frames, cursor: neferclient.CursorDefault}
	93	+	// Shutdown order: close the connection first, which drops its descriptor
	94	+	// watches and destroys every Wayland object, then free the renderer and
	95	+	// its GPU resources (including the release eventfds).
88	96		defer func() {
	97	+	err = errors.Join(err, conn.Close())
89	98		if a.r != nil {
90	99		err = errors.Join(err, a.r.Close())
91	100		}
92		-	err = errors.Join(err, conn.Close())
93	101		}()
94	102		a.surf, err = conn.NewLayerSurface(neferclient.LayerConfig{
95	103		Level: neferclient.LayerTop,

@@ -107,7 +115,7 @@ func run(ctx context.Context, frames int) (err error) {
107	115		for !a.done {
108	116		select {
109	117		case <-ctx.Done():
110		-	return nil
	118	+	return nil // interrupt or SIGTERM: a clean exit
111	119		case <-conn.Wake():
112	120		if err = conn.Dispatch(a); err != nil {
113	121		return fmt.Errorf("dispatch: %w", err)

@@ -131,10 +139,19 @@ func run(ctx context.Context, frames int) (err error) {
131	139
132	140		// FeedbackDone: dmabuf feedback → nefergui.RendererConfig. The renderer opens
133	141		// the compositor's main device and picks a format and modifier from the list.
	142	+	//
	143	+	// Only the first complete feedback is used. A later one (the compositor
	144	+	// changing its preferred device or formats) is ignored: this demo assumes a
	145	+	// single GPU, and rebuilding the renderer is application policy that would
	146	+	// obscure the glue. A real application would create a new Renderer and
	147	+	// re-import its buffers here.
134	148		func (a *app) FeedbackDone(neferclient.SurfaceID) { a.setup() }
135	149
136	150		func (a *app) Configure(neferclient.SurfaceID, int32, int32) {
137		-	a.configured, a.canPresent = true, true
	151	+	if !a.configured { // later configures must not lift the frame-callback gate
	152	+	a.canPresent = true
	153	+	}
	154	+	a.configured = true
138	155		a.resize()
139	156		a.setup()
140	157		}

@@ -240,7 +257,7 @@ func (a app) Key(ev neferclient.KeyEvent) {
240	257		Text: ev.Text, // valid only during the call, as for Input
241	258		Pressed: ev.Pressed,
242	259		Repeat: ev.Repeat,
243		-	Modifiers: nefergui.Modifiers(ev.Modifiers & 0x0f), // shift, ctrl, alt, super
	260	+	Modifiers: nefergui.Modifiers(ev.Modifiers & guiMods),
244	261		})
245	262		}
246	263

@@ -284,6 +301,10 @@ func (a *app) present() error {
284	301		if err := a.surf.DestroyBuffer(rt.Buffer); err != nil {
285	302		return fmt.Errorf("destroy retired buffer %d: %w", rt.Buffer, err)
286	303		}
	304	+	// The release timeline of a buffer is imported under the buffer's id.
	305	+	if err := a.surf.DestroyTimeline(rt.Buffer); err != nil {
	306	+	return fmt.Errorf("destroy retired timeline %d: %w", rt.Buffer, err)
	307	+	}
287	308		}
288	309		if out.NewBuffer {
289	310		buf := neferclient.Buffer{

 	"fmt"
 	"os"
 	"os/signal"
+	"syscall"
 	"time"
 	"github.com/bnema/neferclient"
 const (
 	surfaceW, surfaceH = 240, 90
 	buttonColor        = "#2060c0"
+	// guiMods is the set of modifiers NeferGUI knows. neferclient and NeferGUI
+	// use the same bit order for them, so the plain bits can be copied.
+	guiMods = neferclient.ModShift | neferclient.ModCtrl | neferclient.ModAlt | neferclient.ModSuper
 )
 type model struct{ count int }
 func main() {
 	frames := flag.Int("frames", 0, "redraw continuously and exit after this many frames (0: run until closed)")
 	flag.Parse()
-	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer stop()
 	if err := run(ctx, *frames); err != nil {
 		fmt.Fprintln(os.Stderr, "layer:", err)
 		return fmt.Errorf("connect: %w", err)
 	}
 	a := &app{conn: conn, frames: frames, cursor: neferclient.CursorDefault}
+	// Shutdown order: close the connection first, which drops its descriptor
+	// watches and destroys every Wayland object, then free the renderer and
+	// its GPU resources (including the release eventfds).
 	defer func() {
+		err = errors.Join(err, conn.Close())
 		if a.r != nil {
 			err = errors.Join(err, a.r.Close())
 		}
-		err = errors.Join(err, conn.Close())
 	}()
 	a.surf, err = conn.NewLayerSurface(neferclient.LayerConfig{
 		Level:    neferclient.LayerTop,
 	for !a.done {
 		select {
 		case <-ctx.Done():
-			return nil
+			return nil // interrupt or SIGTERM: a clean exit
 		case <-conn.Wake():
 			if err = conn.Dispatch(a); err != nil {
 				return fmt.Errorf("dispatch: %w", err)
 // FeedbackDone: dmabuf feedback → nefergui.RendererConfig. The renderer opens
 // the compositor's main device and picks a format and modifier from the list.
+//
+// Only the first complete feedback is used. A later one (the compositor
+// changing its preferred device or formats) is ignored: this demo assumes a
+// single GPU, and rebuilding the renderer is application policy that would
+// obscure the glue. A real application would create a new Renderer and
+// re-import its buffers here.
 func (a *app) FeedbackDone(neferclient.SurfaceID) { a.setup() }
 func (a *app) Configure(neferclient.SurfaceID, int32, int32) {
-	a.configured, a.canPresent = true, true
+	if !a.configured { // later configures must not lift the frame-callback gate
+		a.canPresent = true
+	}
+	a.configured = true
 	a.resize()
 	a.setup()
 }
 		Text:      ev.Text, // valid only during the call, as for Input
 		Pressed:   ev.Pressed,
 		Repeat:    ev.Repeat,
-		Modifiers: nefergui.Modifiers(ev.Modifiers & 0x0f), // shift, ctrl, alt, super
+		Modifiers: nefergui.Modifiers(ev.Modifiers & guiMods),
 	})
 }
 		if err := a.surf.DestroyBuffer(rt.Buffer); err != nil {
 			return fmt.Errorf("destroy retired buffer %d: %w", rt.Buffer, err)
 		}
+		// The release timeline of a buffer is imported under the buffer's id.
+		if err := a.surf.DestroyTimeline(rt.Buffer); err != nil {
+			return fmt.Errorf("destroy retired timeline %d: %w", rt.Buffer, err)
+		}
 	}
 	if out.NewBuffer {
 		buf := neferclient.Buffer{