Ignore stale Android call surfaces during activity replacement

tools/chatgui-android/app/src/main/java/com/utun/chat/data/CallVideoEngine.kt

@@ -105,6 +105,7 @@ class CallVideoEngine(private val context: Context, private val id: Long) {
     }
 
     fun surface(surface: Surface?, release: () -> Unit = {}) = player.surface(surface, release)
+    fun detachSurface(surface: Surface) = player.detach(surface)
     fun select(settings: CallVideoSettings) { handler.post {
         if (!stopped) { wanted = settings; excluded = emptySet(); mutable.value = mutable.value.copy(settings = settings) }
     } }

tools/chatgui-android/app/src/main/java/com/utun/chat/data/CallVideoPlayer.kt

@@ -9,7 +9,7 @@ import java.util.concurrent.ConcurrentLinkedQueue
 /** Один RX worker; удерживаем output buffer до фактического audio PTS. Новое поколение ждёт drain старого. */
 internal class CallVideoPlayer(private val id: Long, private val failure: (String) -> Unit) {
     @Volatile private var running = true
-    private data class Output(val surface: Surface?, val release: () -> Unit)
+    private data class Output(val surface: Surface?, val release: () -> Unit, val detach: Surface? = null)
     private val outputs = ConcurrentLinkedQueue<Output>()
     private val displayed = MutableStateFlow<CallVideoFormat?>(null)
     val display: StateFlow<CallVideoFormat?> = displayed
@@ -18,6 +18,9 @@ internal class CallVideoPlayer(private val id: Long, private val failure: (Strin
     @Synchronized fun surface(surface: Surface?, release: () -> Unit = {}) {
         if (running) outputs.add(Output(surface, release)) else release()
     }
+    @Synchronized fun detach(surface: Surface) {
+        if (running) outputs.add(Output(null, {}, surface))
+    }
     fun decoders(value: Map<Int, CallVideoCodec.Companion.Decoder>) { verified = value }
     fun stop() { synchronized(this) { running = false }; worker.join() }
 
@@ -39,6 +42,7 @@ internal class CallVideoPlayer(private val id: Long, private val failure: (Strin
                     val now = System.nanoTime()
                     while (true) {
                         val next = outputs.poll() ?: break
+                        if (next.detach != null && output?.surface !== next.detach) continue
                         close(); output?.release?.invoke(); output = next; surface = next.surface
                         pending = null; displayed.value = null; CallVideoNative.requestKey(id)
                     }

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/screens/CallVideoPanel.kt

@@ -91,7 +91,7 @@ internal fun CallVideoPreview(video: CallVideoEngine, modifier: Modifier = Modif
 }
 
 private class CallVideoTexture(context: Context, private val video: CallVideoEngine) : TextureView(context) {
-    private var attached = false
+    private var attached: Surface? = null
     private var closed = false
     var format: CallVideoFormat? = null
         set(value) { field = value; fit() }
@@ -100,7 +100,7 @@ private class CallVideoTexture(context: Context, private val video: CallVideoEng
         surfaceTextureListener = object : SurfaceTextureListener {
             override fun onSurfaceTextureAvailable(texture: SurfaceTexture, width: Int, height: Int) {
                 if (closed) return
-                val surface = Surface(texture); attached = true
+                val surface = Surface(texture); attached = surface
                 // RX worker освобождает Surface/texture только после остановки MediaCodec.
                 video.surface(surface) { surface.release(); texture.release() }; fit()
             }
@@ -117,7 +117,7 @@ private class CallVideoTexture(context: Context, private val video: CallVideoEng
         val scale = minOf(width.toFloat() / w, height.toFloat() / h)
         setTransform(Matrix().apply { setScale(w * scale / width, h * scale / height, width / 2f, height / 2f) })
     }
-    private fun closeOutput() { if (attached) { attached = false; video.surface(null) } }
+    private fun closeOutput() { attached?.let(video::detachSurface); attached = null }
     fun close() { closed = true; closeOutput() }
 }