3f8c6a5 Add experimental multi-threaded CEF loop mode · dumber

M internal/infrastructure/cef/engine.go +11 -2


@@ -29,8 +29,9 @@ type Engine struct {
29	29		factory *WebViewFactory
30	30		pool *WebViewPool
31	31
32		-	externalMessagePump bool
33		-	manualPumpInterval int64
	32	+	multiThreadedMessageLoop bool
	33	+	externalMessagePump bool
	34	+	manualPumpInterval int64
34	35
35	36		// nextWorkAtMs is the next deadline, in Unix milliseconds, when
36	37		// CefDoMessageLoopWork should run. It is written from any Chromium thread

@@ -152,6 +153,7 @@ func (e *Engine) ConfigureDownloads(_ context.Context, _ string, _ port.Download
152	153		func (e *Engine) OnToolkitReady(_ context.Context) error {
153	154		log := logging.FromContext(e.ctx)
154	155		log.Debug().
	156	+	Bool("multi_threaded_message_loop", e.multiThreadedMessageLoop).
155	157		Bool("external_message_pump", e.externalMessagePump).
156	158		Int64("manual_pump_interval_ms", e.manualPumpInterval).
157	159		Msg("cef: OnToolkitReady called, starting message pump")

@@ -344,6 +346,10 @@ func (e *Engine) scheduleMessagePumpWork(delayMs int64) {
344	346		}
345	347
346	348		func (e *Engine) startMessagePump() {
	349	+	if e.multiThreadedMessageLoop {
	350	+	logging.FromContext(e.ctx).Info().Msg("cef: multi-threaded message loop enabled, skipping external/manual pump")
	351	+	return
	352	+	}
347	353		if e.externalMessagePump {
348	354		e.startExternalMessagePump()
349	355		return

@@ -458,6 +464,9 @@ func (e *Engine) startManualMessagePump() {
458	464		}
459	465
460	466		func (e *Engine) stopMessagePump() {
	467	+	if e.multiThreadedMessageLoop {
	468	+	return
	469	+	}
461	470		e.pumpClosing.Store(true)
462	471		e.pumpEnabled.Store(false)
463	472		e.nextWorkAtMs.Store(0)

 	factory *WebViewFactory
 	pool    *WebViewPool
-	externalMessagePump bool
+	multiThreadedMessageLoop bool
-	manualPumpInterval  int64
+	externalMessagePump      bool
+	manualPumpInterval       int64
 	// nextWorkAtMs is the next deadline, in Unix milliseconds, when
 	// CefDoMessageLoopWork should run. It is written from any Chromium thread
 func (e *Engine) OnToolkitReady(_ context.Context) error {
 	log := logging.FromContext(e.ctx)
 	log.Debug().
+		Bool("multi_threaded_message_loop", e.multiThreadedMessageLoop).
 		Bool("external_message_pump", e.externalMessagePump).
 		Int64("manual_pump_interval_ms", e.manualPumpInterval).
 		Msg("cef: OnToolkitReady called, starting message pump")
 }
 func (e *Engine) startMessagePump() {
+	if e.multiThreadedMessageLoop {
+		logging.FromContext(e.ctx).Info().Msg("cef: multi-threaded message loop enabled, skipping external/manual pump")
+		return
+	}
 	if e.externalMessagePump {
 		e.startExternalMessagePump()
 		return
 }
 func (e *Engine) stopMessagePump() {
+	if e.multiThreadedMessageLoop {
+		return
+	}
 	e.pumpClosing.Store(true)
 	e.pumpEnabled.Store(false)
 	e.nextWorkAtMs.Store(0)

M internal/infrastructure/cef/engine_init.go +9 -3


@@ -18,7 +18,11 @@ func NewEngine(ctx context.Context, cfg config.CEFEngineConfig) (*Engine, error)
18	18		logger := logging.FromContext(ctx)
19	19		// 1. Initialize CEF.
20	20		settings := purecef.DefaultSettings()
	21	+	settings.MultiThreadedMessageLoop = parseBoolEnv("DUMBER_CEF_MULTI_THREADED_MESSAGE_LOOP", false)
21	22		settings.ExternalMessagePump = parseBoolEnv("DUMBER_CEF_EXTERNAL_PUMP", settings.ExternalMessagePump)
	23	+	if settings.MultiThreadedMessageLoop {
	24	+	settings.ExternalMessagePump = false
	25	+	}
22	26		if cfg.CEFDir != "" {
23	27		settings.CEFDir = cfg.CEFDir
24	28		}

@@ -52,12 +56,14 @@ func NewEngine(ctx context.Context, cfg config.CEFEngineConfig) (*Engine, error)
52	56
53	57		// 2. Build the engine early so the App can reference it for the pump callback.
54	58		eng := &Engine{
55		-	ctx: ctx,
56		-	externalMessagePump: settings.ExternalMessagePump,
57		-	manualPumpInterval: parseInt64Env("DUMBER_CEF_MANUAL_PUMP_MS", 10),
	59	+	ctx: ctx,
	60	+	multiThreadedMessageLoop: settings.MultiThreadedMessageLoop,
	61	+	externalMessagePump: settings.ExternalMessagePump,
	62	+	manualPumpInterval: parseInt64Env("DUMBER_CEF_MANUAL_PUMP_MS", 10),
58	63		}
59	64
60	65		logger.Info().
	66	+	Bool("multi_threaded_message_loop", settings.MultiThreadedMessageLoop).
61	67		Bool("external_message_pump", settings.ExternalMessagePump).
62	68		Int64("manual_pump_interval_ms", eng.manualPumpInterval).
63	69		Msg("cef: configured message pump mode")

 	logger := logging.FromContext(ctx)
 	// 1. Initialize CEF.
 	settings := purecef.DefaultSettings()
+	settings.MultiThreadedMessageLoop = parseBoolEnv("DUMBER_CEF_MULTI_THREADED_MESSAGE_LOOP", false)
 	settings.ExternalMessagePump = parseBoolEnv("DUMBER_CEF_EXTERNAL_PUMP", settings.ExternalMessagePump)
+	if settings.MultiThreadedMessageLoop {
+		settings.ExternalMessagePump = false
+	}
 	if cfg.CEFDir != "" {
 		settings.CEFDir = cfg.CEFDir
 	}
 	// 2. Build the engine early so the App can reference it for the pump callback.
 	eng := &Engine{
-		ctx:                 ctx,
+		ctx:                      ctx,
-		externalMessagePump: settings.ExternalMessagePump,
+		multiThreadedMessageLoop: settings.MultiThreadedMessageLoop,
-		manualPumpInterval:  parseInt64Env("DUMBER_CEF_MANUAL_PUMP_MS", 10),
+		externalMessagePump:      settings.ExternalMessagePump,
+		manualPumpInterval:       parseInt64Env("DUMBER_CEF_MANUAL_PUMP_MS", 10),
 	}
 	logger.Info().
+		Bool("multi_threaded_message_loop", settings.MultiThreadedMessageLoop).
 		Bool("external_message_pump", settings.ExternalMessagePump).
 		Int64("manual_pump_interval_ms", eng.manualPumpInterval).
 		Msg("cef: configured message pump mode")

M internal/infrastructure/cef/factory.go +5 -2


@@ -109,8 +109,11 @@ func (f *WebViewFactory) Create(ctx context.Context) (port.WebView, error) {
109	109
110	110		// On subsequent resizes, notify CEF so it re-queries GetViewRect.
111	111		pipeline.onResizeCB = func(_, _ int32) {
112		-	if wv.host != nil {
113		-	wv.host.WasResized()
	112	+	wv.mu.RLock()
	113	+	host := wv.host
	114	+	wv.mu.RUnlock()
	115	+	if host != nil {
	116	+	host.WasResized()
114	117		}
115	118		}
116	119

 	// On subsequent resizes, notify CEF so it re-queries GetViewRect.
 	pipeline.onResizeCB = func(_, _ int32) {
-		if wv.host != nil {
+		wv.mu.RLock()
-			wv.host.WasResized()
+		host := wv.host
+		wv.mu.RUnlock()
+		if host != nil {
+			host.WasResized()
 		}
 	}

M internal/infrastructure/cef/webview.go +74 -21


@@ -9,6 +9,7 @@ import (
9	9		"unsafe"
10	10
11	11		purecef "github.com/bnema/purego-cef/cef"
	12	+	"github.com/jwijenbergh/puregotk/v4/glib"
12	13
13	14		"github.com/bnema/dumber/internal/application/port"
14	15		)

@@ -92,12 +93,16 @@ func (wv *WebView) LoadURI(_ context.Context, uri string) error {
92	93		if wv.destroyed.Load() {
93	94		return errDestroyed
94	95		}
95		-	if wv.browser == nil {
	96	+	wv.mu.Lock()
	97	+	browser := wv.browser
	98	+	if browser == nil {
96	99		// Browser not yet created — queue the URI for OnAfterCreated.
97	100		wv.pendingURI = uri
	101	+	wv.mu.Unlock()
98	102		return nil
99	103		}
100		-	wv.browser.GetMainFrame().LoadURL(uri)
	104	+	wv.mu.Unlock()
	105	+	browser.GetMainFrame().LoadURL(uri)
101	106		return nil
102	107		}
103	108

@@ -106,11 +111,14 @@ func (wv *WebView) LoadHTML(_ context.Context, content, _ string) error {
106	111		if wv.destroyed.Load() {
107	112		return errDestroyed
108	113		}
109		-	if wv.browser == nil {
	114	+	wv.mu.RLock()
	115	+	browser := wv.browser
	116	+	wv.mu.RUnlock()
	117	+	if browser == nil {
110	118		return errNoBrowser
111	119		}
112	120		dataURL := "data:text/html;base64," + base64.StdEncoding.EncodeToString([]byte(content))
113		-	wv.browser.GetMainFrame().LoadURL(dataURL)
	121	+	browser.GetMainFrame().LoadURL(dataURL)
114	122		return nil
115	123		}
116	124

@@ -119,10 +127,13 @@ func (wv *WebView) Reload(_ context.Context) error {
119	127		if wv.destroyed.Load() {
120	128		return errDestroyed
121	129		}
122		-	if wv.browser == nil {
	130	+	wv.mu.RLock()
	131	+	browser := wv.browser
	132	+	wv.mu.RUnlock()
	133	+	if browser == nil {
123	134		return errNoBrowser
124	135		}
125		-	wv.browser.Reload()
	136	+	browser.Reload()
126	137		return nil
127	138		}
128	139

@@ -131,10 +142,13 @@ func (wv *WebView) ReloadBypassCache(_ context.Context) error {
131	142		if wv.destroyed.Load() {
132	143		return errDestroyed
133	144		}
134		-	if wv.browser == nil {
	145	+	wv.mu.RLock()
	146	+	browser := wv.browser
	147	+	wv.mu.RUnlock()
	148	+	if browser == nil {
135	149		return errNoBrowser
136	150		}
137		-	wv.browser.ReloadIgnoreCache()
	151	+	browser.ReloadIgnoreCache()
138	152		return nil
139	153		}
140	154

@@ -143,10 +157,13 @@ func (wv *WebView) Stop(_ context.Context) error {
143	157		if wv.destroyed.Load() {
144	158		return errDestroyed
145	159		}
146		-	if wv.browser == nil {
	160	+	wv.mu.RLock()
	161	+	browser := wv.browser
	162	+	wv.mu.RUnlock()
	163	+	if browser == nil {
147	164		return errNoBrowser
148	165		}
149		-	wv.browser.StopLoad()
	166	+	browser.StopLoad()
150	167		return nil
151	168		}
152	169

@@ -155,10 +172,13 @@ func (wv *WebView) GoBack(_ context.Context) error {
155	172		if wv.destroyed.Load() {
156	173		return errDestroyed
157	174		}
158		-	if wv.browser == nil {
	175	+	wv.mu.RLock()
	176	+	browser := wv.browser
	177	+	wv.mu.RUnlock()
	178	+	if browser == nil {
159	179		return errNoBrowser
160	180		}
161		-	wv.browser.GoBack()
	181	+	browser.GoBack()
162	182		return nil
163	183		}
164	184

@@ -167,10 +187,13 @@ func (wv *WebView) GoForward(_ context.Context) error {
167	187		if wv.destroyed.Load() {
168	188		return errDestroyed
169	189		}
170		-	if wv.browser == nil {
	190	+	wv.mu.RLock()
	191	+	browser := wv.browser
	192	+	wv.mu.RUnlock()
	193	+	if browser == nil {
171	194		return errNoBrowser
172	195		}
173		-	wv.browser.GoForward()
	196	+	browser.GoForward()
174	197		return nil
175	198		}
176	199

@@ -295,10 +318,16 @@ func (wv WebView) SetCallbacks(cb port.WebViewCallbacks) {
295	318
296	319		// RunJavaScript executes a script in the main world. Fire-and-forget.
297	320		func (wv *WebView) RunJavaScript(_ context.Context, script string) {
298		-	if wv.destroyed.Load() \|\| wv.browser == nil {
	321	+	if wv.destroyed.Load() {
299	322		return
300	323		}
301		-	wv.browser.GetMainFrame().ExecuteJavaScript(script, "", 0)
	324	+	wv.mu.RLock()
	325	+	browser := wv.browser
	326	+	wv.mu.RUnlock()
	327	+	if browser == nil {
	328	+	return
	329	+	}
	330	+	browser.GetMainFrame().ExecuteJavaScript(script, "", 0)
302	331		}
303	332
304	333		// SetBackgroundColor is a no-op in Phase 1.

@@ -321,8 +350,11 @@ func (wv *WebView) Destroy() {
321	350		if !wv.destroyed.CompareAndSwap(false, true) {
322	351		return
323	352		}
324		-	if wv.host != nil {
325		-	wv.host.CloseBrowser(1)
	353	+	wv.mu.RLock()
	354	+	host := wv.host
	355	+	wv.mu.RUnlock()
	356	+	if host != nil {
	357	+	host.CloseBrowser(1)
326	358		}
327	359		if wv.pipeline != nil {
328	360		wv.pipeline.destroy()

@@ -354,7 +386,9 @@ func (wv *WebView) updateURI(uri string) {
354	386		cb := wv.callbacks
355	387		wv.mu.RUnlock()
356	388		if cb != nil && cb.OnURIChanged != nil {
357		-	cb.OnURIChanged(uri)
	389	+	wv.runOnGTK(func() {
	390	+	cb.OnURIChanged(uri)
	391	+	})
358	392		}
359	393		}
360	394

@@ -367,7 +401,9 @@ func (wv *WebView) updateTitle(title string) {
367	401		cb := wv.callbacks
368	402		wv.mu.RUnlock()
369	403		if cb != nil && cb.OnTitleChanged != nil {
370		-	cb.OnTitleChanged(title)
	404	+	wv.runOnGTK(func() {
	405	+	cb.OnTitleChanged(title)
	406	+	})
371	407		}
372	408		}
373	409

@@ -380,7 +416,9 @@ func (wv *WebView) updateProgress(progress float64) {
380	416		cb := wv.callbacks
381	417		wv.mu.RUnlock()
382	418		if cb != nil && cb.OnProgressChanged != nil {
383		-	cb.OnProgressChanged(progress)
	419	+	wv.runOnGTK(func() {
	420	+	cb.OnProgressChanged(progress)
	421	+	})
384	422		}
385	423		}
386	424

@@ -392,5 +430,20 @@ func (wv *WebView) updateLoadState(loading, back, fwd bool) {
392	430		wv.mu.Unlock()
393	431		}
394	432
	433	+	func (wv *WebView) runOnGTK(fn func()) {
	434	+	if fn == nil {
	435	+	return
	436	+	}
	437	+	if wv.engine == nil \|\| !wv.engine.multiThreadedMessageLoop {
	438	+	fn()
	439	+	return
	440	+	}
	441	+
	442	+	cb := glib.SourceOnceFunc(func(_ uintptr) {
	443	+	fn()
	444	+	})
	445	+	glib.IdleAddOnce(&cb, 0)
	446	+	}
	447	+
395	448		// suppress unused import for unsafe (used by NativeWidget via GoPointer).
396	449		var _ = unsafe.Pointer(nil)

 	"unsafe"
 	purecef "github.com/bnema/purego-cef/cef"
+	"github.com/jwijenbergh/puregotk/v4/glib"
 	"github.com/bnema/dumber/internal/application/port"
 )
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.Lock()
+	browser := wv.browser
+	if browser == nil {
 		// Browser not yet created — queue the URI for OnAfterCreated.
 		wv.pendingURI = uri
+		wv.mu.Unlock()
 		return nil
 	}
-	wv.browser.GetMainFrame().LoadURL(uri)
+	wv.mu.Unlock()
+	browser.GetMainFrame().LoadURL(uri)
 	return nil
 }
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
 		return errNoBrowser
 	}
 	dataURL := "data:text/html;base64," + base64.StdEncoding.EncodeToString([]byte(content))
-	wv.browser.GetMainFrame().LoadURL(dataURL)
+	browser.GetMainFrame().LoadURL(dataURL)
 	return nil
 }
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
 		return errNoBrowser
 	}
-	wv.browser.Reload()
+	browser.Reload()
 	return nil
 }
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
 		return errNoBrowser
 	}
-	wv.browser.ReloadIgnoreCache()
+	browser.ReloadIgnoreCache()
 	return nil
 }
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
 		return errNoBrowser
 	}
-	wv.browser.StopLoad()
+	browser.StopLoad()
 	return nil
 }
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
 		return errNoBrowser
 	}
-	wv.browser.GoBack()
+	browser.GoBack()
 	return nil
 }
 	if wv.destroyed.Load() {
 		return errDestroyed
 	}
-	if wv.browser == nil {
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
 		return errNoBrowser
 	}
-	wv.browser.GoForward()
+	browser.GoForward()
 	return nil
 }
 // RunJavaScript executes a script in the main world. Fire-and-forget.
 func (wv *WebView) RunJavaScript(_ context.Context, script string) {
-	if wv.destroyed.Load() || wv.browser == nil {
+	if wv.destroyed.Load() {
 		return
 	}
-	wv.browser.GetMainFrame().ExecuteJavaScript(script, "", 0)
+	wv.mu.RLock()
+	browser := wv.browser
+	wv.mu.RUnlock()
+	if browser == nil {
+		return
+	}
+	browser.GetMainFrame().ExecuteJavaScript(script, "", 0)
 }
 // SetBackgroundColor is a no-op in Phase 1.
 	if !wv.destroyed.CompareAndSwap(false, true) {
 		return
 	}
-	if wv.host != nil {
+	wv.mu.RLock()
-		wv.host.CloseBrowser(1)
+	host := wv.host
+	wv.mu.RUnlock()
+	if host != nil {
+		host.CloseBrowser(1)
 	}
 	if wv.pipeline != nil {
 		wv.pipeline.destroy()
 	cb := wv.callbacks
 	wv.mu.RUnlock()
 	if cb != nil && cb.OnURIChanged != nil {
-		cb.OnURIChanged(uri)
+		wv.runOnGTK(func() {
+			cb.OnURIChanged(uri)
+		})
 	}
 }
 	cb := wv.callbacks
 	wv.mu.RUnlock()
 	if cb != nil && cb.OnTitleChanged != nil {
-		cb.OnTitleChanged(title)
+		wv.runOnGTK(func() {
+			cb.OnTitleChanged(title)
+		})
 	}
 }
 	cb := wv.callbacks
 	wv.mu.RUnlock()
 	if cb != nil && cb.OnProgressChanged != nil {
-		cb.OnProgressChanged(progress)
+		wv.runOnGTK(func() {
+			cb.OnProgressChanged(progress)
+		})
 	}
 }
 	wv.mu.Unlock()
 }
+func (wv *WebView) runOnGTK(fn func()) {
+	if fn == nil {
+		return
+	}
+	if wv.engine == nil || !wv.engine.multiThreadedMessageLoop {
+		fn()
+		return
+	}
+	cb := glib.SourceOnceFunc(func(_ uintptr) {
+		fn()
+	})
+	glib.IdleAddOnce(&cb, 0)
+}
 // suppress unused import for unsafe (used by NativeWidget via GoPointer).
 var _ = unsafe.Pointer(nil)

M internal/infrastructure/cef/webview_handlers.go +60 -16


@@ -99,15 +99,31 @@ func (h *handlerSet) OnPopupShow(_ purecef.Browser, _ int32) {}
99	99		func (h handlerSet) OnPopupSize(_ purecef.Browser, _ purecef.Rect) {}
100	100
101	101		// OnPaint receives the BGRA pixel buffer from CEF and forwards dirty rects
102		-	// to the render pipeline for GPU upload.
	102	+	// to the render pipeline for GPU upload. With a multi-threaded CEF UI loop we
	103	+	// must first copy the transient CEF buffer before hopping back to GTK.
103	104		func (h *handlerSet) OnPaint(
104	105		_ purecef.Browser, _ purecef.PaintElementType,
105	106		dirtyRects []purecef.Rect, buffer unsafe.Pointer, width, height int32,
106	107		) {
	108	+	if buffer == nil \|\| width <= 0 \|\| height <= 0 {
	109	+	return
	110	+	}
107	111		rects := make([]rect, len(dirtyRects))
108	112		for i, dr := range dirtyRects {
109	113		rects[i] = rect{X: dr.X, Y: dr.Y, Width: dr.Width, Height: dr.Height}
110	114		}
	115	+	if h.wv.engine != nil && h.wv.engine.multiThreadedMessageLoop {
	116	+	bufSize := int(width) * int(height) * 4
	117	+	if bufSize <= 0 {
	118	+	return
	119	+	}
	120	+	pixels := make([]byte, bufSize)
	121	+	copy(pixels, unsafe.Slice((*byte)(buffer), bufSize))
	122	+	h.wv.runOnGTK(func() {
	123	+	h.wv.pipeline.handlePaint(unsafe.Pointer(&pixels[0]), width, height, rects)
	124	+	})
	125	+	return
	126	+	}
111	127		h.wv.pipeline.handlePaint(buffer, width, height, rects)
112	128		}
113	129

@@ -170,10 +186,14 @@ func (h *handlerSet) OnFullscreenModeChange(_ purecef.Browser, fullscreen int32)
170	186		return
171	187		}
172	188		if entering && cb.OnEnterFullscreen != nil {
173		-	cb.OnEnterFullscreen()
	189	+	h.wv.runOnGTK(func() {
	190	+	cb.OnEnterFullscreen()
	191	+	})
174	192		}
175	193		if !entering && cb.OnLeaveFullscreen != nil {
176		-	cb.OnLeaveFullscreen()
	194	+	h.wv.runOnGTK(func() {
	195	+	cb.OnLeaveFullscreen()
	196	+	})
177	197		}
178	198		}
179	199

@@ -185,7 +205,9 @@ func (h *handlerSet) OnStatusMessage(_ purecef.Browser, value string) {
185	205		cb := h.wv.callbacks
186	206		h.wv.mu.RUnlock()
187	207		if cb != nil && cb.OnLinkHover != nil {
188		-	cb.OnLinkHover(value)
	208	+	h.wv.runOnGTK(func() {
	209	+	cb.OnLinkHover(value)
	210	+	})
189	211		}
190	212		}
191	213

@@ -202,7 +224,9 @@ func (h *handlerSet) OnLoadingProgressChange(_ purecef.Browser, progress float64
202	224
203	225		func (h handlerSet) OnCursorChange(_ purecef.Browser, _ uintptr, cursorType purecef.CursorType, _ purecef.CursorInfo) int32 {
204	226		name := cefCursorToGDKName(cursorType)
205		-	h.wv.pipeline.glArea.SetCursorFromName(&name)
	227	+	h.wv.runOnGTK(func() {
	228	+	h.wv.pipeline.glArea.SetCursorFromName(&name)
	229	+	})
206	230		return 1 // handled
207	231		}
208	232

@@ -226,9 +250,13 @@ func (h *handlerSet) OnLoadingStateChange(_ purecef.Browser, isloading, cangobac
226	250		h.wv.mu.RUnlock()
227	251		if cb != nil && cb.OnLoadChanged != nil {
228	252		if loading {
229		-	cb.OnLoadChanged(port.LoadStarted)
	253	+	h.wv.runOnGTK(func() {
	254	+	cb.OnLoadChanged(port.LoadStarted)
	255	+	})
230	256		} else {
231		-	cb.OnLoadChanged(port.LoadFinished)
	257	+	h.wv.runOnGTK(func() {
	258	+	cb.OnLoadChanged(port.LoadFinished)
	259	+	})
232	260		}
233	261		}
234	262		}

@@ -245,7 +273,9 @@ func (h *handlerSet) OnLoadStart(_ purecef.Browser, frame purecef.Frame, _ purec
245	273		cb := h.wv.callbacks
246	274		h.wv.mu.RUnlock()
247	275		if cb != nil && cb.OnLoadChanged != nil {
248		-	cb.OnLoadChanged(port.LoadCommitted)
	276	+	h.wv.runOnGTK(func() {
	277	+	cb.OnLoadChanged(port.LoadCommitted)
	278	+	})
249	279		}
250	280		}
251	281

@@ -268,10 +298,14 @@ func (h *handlerSet) OnLoadEnd(_ purecef.Browser, frame purecef.Frame, httpStatu
268	298		h.wv.mu.RUnlock()
269	299		if cb != nil {
270	300		if cb.OnLoadChanged != nil {
271		-	cb.OnLoadChanged(port.LoadFinished)
	301	+	h.wv.runOnGTK(func() {
	302	+	cb.OnLoadChanged(port.LoadFinished)
	303	+	})
272	304		}
273	305		if cb.OnProgressChanged != nil {
274		-	cb.OnProgressChanged(1.0)
	306	+	h.wv.runOnGTK(func() {
	307	+	cb.OnProgressChanged(1.0)
	308	+	})
275	309		}
276	310		}
277	311		}

@@ -316,13 +350,19 @@ func (h *handlerSet) OnAfterCreated(browser purecef.Browser) {
316	350		if h.wv.engine != nil {
317	351		h.wv.engine.recordBrowserAfterCreated(browser)
318	352		}
	353	+	host := browser.GetHost()
	354	+
	355	+	h.wv.mu.Lock()
319	356		h.wv.browser = browser
320		-	h.wv.host = browser.GetHost()
321		-	h.wv.input.setHost(h.wv.host)
	357	+	h.wv.host = host
	358	+	uri := h.wv.pendingURI
	359	+	h.wv.pendingURI = ""
	360	+	h.wv.mu.Unlock()
	361	+
	362	+	h.wv.input.setHost(host)
322	363
323	364		// Replay any navigation that was requested before the browser existed.
324		-	if uri := h.wv.pendingURI; uri != "" {
325		-	h.wv.pendingURI = ""
	365	+	if uri != "" {
326	366		browser.GetMainFrame().LoadURL(uri)
327	367		}
328	368		}

@@ -338,7 +378,9 @@ func (h *handlerSet) OnBeforeClose(_ purecef.Browser) {
338	378		cb := h.wv.callbacks
339	379		h.wv.mu.RUnlock()
340	380		if cb != nil && cb.OnClose != nil {
341		-	cb.OnClose()
	381	+	h.wv.runOnGTK(func() {
	382	+	cb.OnClose()
	383	+	})
342	384		}
343	385		}
344	386

@@ -424,7 +466,9 @@ func (h *handlerSet) OnRenderProcessTerminated(_ purecef.Browser, status purecef
424	466		uri := h.wv.uri
425	467		h.wv.mu.RUnlock()
426	468		if cb != nil && cb.OnWebProcessTerminated != nil {
427		-	cb.OnWebProcessTerminated(reason, label, uri)
	469	+	h.wv.runOnGTK(func() {
	470	+	cb.OnWebProcessTerminated(reason, label, uri)
	471	+	})
428	472		}
429	473		}
430	474

 func (h *handlerSet) OnPopupSize(_ purecef.Browser, _ *purecef.Rect) {}
 // OnPaint receives the BGRA pixel buffer from CEF and forwards dirty rects
-// to the render pipeline for GPU upload.
+// to the render pipeline for GPU upload. With a multi-threaded CEF UI loop we
+// must first copy the transient CEF buffer before hopping back to GTK.
 func (h *handlerSet) OnPaint(
 	_ purecef.Browser, _ purecef.PaintElementType,
 	dirtyRects []purecef.Rect, buffer unsafe.Pointer, width, height int32,
 ) {
+	if buffer == nil || width <= 0 || height <= 0 {
+		return
+	}
 	rects := make([]rect, len(dirtyRects))
 	for i, dr := range dirtyRects {
 		rects[i] = rect{X: dr.X, Y: dr.Y, Width: dr.Width, Height: dr.Height}
 	}
+	if h.wv.engine != nil && h.wv.engine.multiThreadedMessageLoop {
+		bufSize := int(width) * int(height) * 4
+		if bufSize <= 0 {
+			return
+		}
+		pixels := make([]byte, bufSize)
+		copy(pixels, unsafe.Slice((*byte)(buffer), bufSize))
+		h.wv.runOnGTK(func() {
+			h.wv.pipeline.handlePaint(unsafe.Pointer(&pixels[0]), width, height, rects)
+		})
+		return
+	}
 	h.wv.pipeline.handlePaint(buffer, width, height, rects)
 }
 		return
 	}
 	if entering && cb.OnEnterFullscreen != nil {
-		cb.OnEnterFullscreen()
+		h.wv.runOnGTK(func() {
+			cb.OnEnterFullscreen()
+		})
 	}
 	if !entering && cb.OnLeaveFullscreen != nil {
-		cb.OnLeaveFullscreen()
+		h.wv.runOnGTK(func() {
+			cb.OnLeaveFullscreen()
+		})
 	}
 }
 	cb := h.wv.callbacks
 	h.wv.mu.RUnlock()
 	if cb != nil && cb.OnLinkHover != nil {
-		cb.OnLinkHover(value)
+		h.wv.runOnGTK(func() {
+			cb.OnLinkHover(value)
+		})
 	}
 }
 func (h *handlerSet) OnCursorChange(_ purecef.Browser, _ uintptr, cursorType purecef.CursorType, _ *purecef.CursorInfo) int32 {
 	name := cefCursorToGDKName(cursorType)
-	h.wv.pipeline.glArea.SetCursorFromName(&name)
+	h.wv.runOnGTK(func() {
+		h.wv.pipeline.glArea.SetCursorFromName(&name)
+	})
 	return 1 // handled
 }
 	h.wv.mu.RUnlock()
 	if cb != nil && cb.OnLoadChanged != nil {
 		if loading {
-			cb.OnLoadChanged(port.LoadStarted)
+			h.wv.runOnGTK(func() {
+				cb.OnLoadChanged(port.LoadStarted)
+			})
 		} else {
-			cb.OnLoadChanged(port.LoadFinished)
+			h.wv.runOnGTK(func() {
+				cb.OnLoadChanged(port.LoadFinished)
+			})
 		}
 	}
 }
 	cb := h.wv.callbacks
 	h.wv.mu.RUnlock()
 	if cb != nil && cb.OnLoadChanged != nil {
-		cb.OnLoadChanged(port.LoadCommitted)
+		h.wv.runOnGTK(func() {
+			cb.OnLoadChanged(port.LoadCommitted)
+		})
 	}
 }
 	h.wv.mu.RUnlock()
 	if cb != nil {
 		if cb.OnLoadChanged != nil {
-			cb.OnLoadChanged(port.LoadFinished)
+			h.wv.runOnGTK(func() {
+				cb.OnLoadChanged(port.LoadFinished)
+			})
 		}
 		if cb.OnProgressChanged != nil {
-			cb.OnProgressChanged(1.0)
+			h.wv.runOnGTK(func() {
+				cb.OnProgressChanged(1.0)
+			})
 		}
 	}
 }
 	if h.wv.engine != nil {
 		h.wv.engine.recordBrowserAfterCreated(browser)
 	}
+	host := browser.GetHost()
+	h.wv.mu.Lock()
 	h.wv.browser = browser
-	h.wv.host = browser.GetHost()
+	h.wv.host = host
-	h.wv.input.setHost(h.wv.host)
+	uri := h.wv.pendingURI
+	h.wv.pendingURI = ""
+	h.wv.mu.Unlock()
+	h.wv.input.setHost(host)
 	// Replay any navigation that was requested before the browser existed.
-	if uri := h.wv.pendingURI; uri != "" {
+	if uri != "" {
-		h.wv.pendingURI = ""
 		browser.GetMainFrame().LoadURL(uri)
 	}
 }
 	cb := h.wv.callbacks
 	h.wv.mu.RUnlock()
 	if cb != nil && cb.OnClose != nil {
-		cb.OnClose()
+		h.wv.runOnGTK(func() {
+			cb.OnClose()
+		})
 	}
 }
 	uri := h.wv.uri
 	h.wv.mu.RUnlock()
 	if cb != nil && cb.OnWebProcessTerminated != nil {
-		cb.OnWebProcessTerminated(reason, label, uri)
+		h.wv.runOnGTK(func() {
+			cb.OnWebProcessTerminated(reason, label, uri)
+		})
 	}
 }