prevent usage of dangling pointer to `MetalDevice` (#666)

* prevent usage of dangling pointer to `MetalDevice`

MetalRedrawer may be disposed during update which leads to use after free

* add test and comment

skiko/src/awtMain/kotlin/org/jetbrains/skiko/redrawer/MetalRedrawer.kt

@@ -25,7 +25,11 @@ internal class MetalRedrawer(
     }
     private var drawLock = Any()
 
-    private val device: Long
+    private var device: Long
+        get() {
+            check(field != 0L) { "Device is not initialized" }
+            return field
+        }
     val adapterName: String
     val adapterMemorySize: Long
 
@@ -60,6 +64,7 @@ internal class MetalRedrawer(
         frameDispatcher.cancel()
         contextHandler.dispose()
         disposeDevice(device)
+        device = 0
         super.dispose()
     }
 
@@ -73,8 +78,10 @@ internal class MetalRedrawer(
         inDrawScope {
             setVSyncEnabled(device, enabled = false)
             update(System.nanoTime())
-            performDraw()
-            setVSyncEnabled(device, properties.isVsyncEnabled)
+            if (!isDisposed) { // Redrawer may be disposed in user code, during `update`
+                performDraw()
+                setVSyncEnabled(device, properties.isVsyncEnabled)
+            }
         }
     }
 

skiko/src/awtTest/kotlin/org/jetbrains/skiko/SkiaLayerTest.kt

@@ -26,6 +26,7 @@ import java.awt.Dimension
 import java.awt.event.WindowEvent
 import javax.swing.JFrame
 import javax.swing.JLayeredPane
+import javax.swing.SwingUtilities
 import javax.swing.WindowConstants
 import kotlin.random.Random
 import kotlin.test.assertNotNull
@@ -508,6 +509,34 @@ class SkiaLayerTest {
         }
     }
 
+    @Test
+    fun `frame disposed inside of immediate repaint`() = uiTest {
+        val onDrawCompleted = CompletableDeferred<Unit>()
+        val window = UiTestWindow(
+            properties = SkiaLayerProperties(
+                isVsyncEnabled = true,
+                isVsyncFramelimitFallbackEnabled = true
+            )
+        )
+        try {
+            window.setLocation(200, 200)
+            window.setSize(400, 400)
+            window.layer.skikoView = object : SkikoView {
+                override fun onRender(canvas: Canvas, width: Int, height: Int, nanoTime: Long) {
+                    window.dispose()
+                    SwingUtilities.invokeLater {
+                        onDrawCompleted.complete(Unit)
+                    }
+                }
+            }
+            window.isVisible = true
+            onDrawCompleted.await()
+        } finally {
+            window.dispose()
+        }
+
+    }
+
     @Test
     fun `render text (Windows)`() {
         testRenderText(OS.Windows)