Fix memory leak because of missing autoreleasepool in offscreen rendering for Swing interop (#764)

skiko/src/awtMain/kotlin/org/jetbrains/skiko/MetalApi.kt

@@ -25,7 +25,26 @@ internal fun MetalAdapter.dispose() {
     disposeAdapter(ptr)
 }
 
+/**
+ * [@autoreleasepool](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmAutoreleasePools.html)
+ */
+@Suppress("SpellCheckingInspection")
+internal inline fun <R> autoreleasepool(block: () -> R): R {
+    val handle = openAutoreleasepool()
+    return try {
+        block()
+    } finally {
+        closeAutoreleasepool(handle)
+    }
+}
+
 private external fun chooseAdapter(adapterPriority: Int): Long
 private external fun disposeAdapter(adapter: Long)
 private external fun getAdapterName(adapter: Long): String
-private external fun getAdapterMemorySize(adapter: Long): Long
\ No newline at end of file
+private external fun getAdapterMemorySize(adapter: Long): Long
+
+@Suppress("SpellCheckingInspection")
+private external fun openAutoreleasepool(): Long
+
+@Suppress("SpellCheckingInspection")
+private external fun closeAutoreleasepool(handle: Long)
\ No newline at end of file

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

@@ -154,11 +154,8 @@ internal class MetalRedrawer(
             // - it makes frames consistent and limits FPS
             displayLinkThrottler.waitVSync(windowPtr = layer.windowHandle)
 
-            val handle = startRendering()
-            try {
+            autoreleasepool {
                 contextHandler.draw()
-            } finally {
-                endRendering(handle)
             }
         }
     }
@@ -188,6 +185,4 @@ internal class MetalRedrawer(
     private external fun setContentScale(device: Long, contentScale: Float)
     private external fun setVSyncEnabled(device: Long, enabled: Boolean)
     private external fun isOccluded(window: Long): Boolean
-    private external fun startRendering(): Long
-    private external fun endRendering(handle: Long)
 }

skiko/src/awtMain/kotlin/org/jetbrains/skiko/swing/MetalSwingRedrawer.kt

@@ -44,21 +44,25 @@ internal class MetalSwingRedrawer(
         super.dispose()
     }
 
-    override fun onRender(g: Graphics2D, width: Int, height: Int, nanoTime: Long) = autoCloseScope {
-        val renderTarget = makeRenderTarget(width, height).autoClose()
-        val surface = Surface.makeFromBackendRenderTarget(
-            context,
-            renderTarget,
-            SurfaceOrigin.TOP_LEFT,
-            SurfaceColorFormat.BGRA_8888,
-            ColorSpace.sRGB,
-            SurfaceProps(pixelGeometry = PixelGeometry.UNKNOWN)
-        )?.autoClose() ?: throw RenderException("Cannot create surface")
-
-        val canvas = surface.canvas
-        canvas.clear(Color.TRANSPARENT)
-        skikoView.onRender(canvas, width, height, nanoTime)
-        flush(surface, g)
+    override fun onRender(g: Graphics2D, width: Int, height: Int, nanoTime: Long) {
+        autoreleasepool {
+            autoCloseScope {
+                val renderTarget = makeRenderTarget(width, height).autoClose()
+                val surface = Surface.makeFromBackendRenderTarget(
+                    context,
+                    renderTarget,
+                    SurfaceOrigin.TOP_LEFT,
+                    SurfaceColorFormat.BGRA_8888,
+                    ColorSpace.sRGB,
+                    SurfaceProps(pixelGeometry = PixelGeometry.UNKNOWN)
+                )?.autoClose() ?: throw RenderException("Cannot create surface")
+
+                val canvas = surface.canvas
+                canvas.clear(Color.TRANSPARENT)
+                skikoView.onRender(canvas, width, height, nanoTime)
+                flush(surface, g)
+            }
+        }
     }
 
     private fun flush(surface: Surface, g: Graphics2D) {

skiko/src/awtMain/objectiveC/macos/MetalApi.mm

@@ -26,6 +26,21 @@
 extern "C"
 {
 
+extern "C" void* objc_autoreleasePoolPush(void);
+extern "C" void objc_autoreleasePoolPop(void*);
+
+JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_MetalApiKt_openAutoreleasepool(
+    JNIEnv * env, jobject redrawer)
+{
+    return (jlong)objc_autoreleasePoolPush();
+}
+
+JNIEXPORT void JNICALL Java_org_jetbrains_skiko_MetalApiKt_closeAutoreleasepool(
+    JNIEnv * env, jobject redrawer, jlong handle)
+{
+    objc_autoreleasePoolPop((void*)handle);
+}
+
 BOOL isUsingIntegratedGPU() {
     kern_return_t kernResult = 0;
     io_iterator_t iterator = IO_OBJECT_NULL;

skiko/src/awtMain/objectiveC/macos/MetalRedrawer.mm

@@ -54,21 +54,6 @@
 extern "C"
 {
 
-extern "C" void* objc_autoreleasePoolPush(void);
-extern "C" void objc_autoreleasePoolPop(void*);
-
-JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_MetalRedrawer_startRendering(
-    JNIEnv * env, jobject redrawer)
-{
-    return (jlong)objc_autoreleasePoolPush();
-}
-
-JNIEXPORT void JNICALL Java_org_jetbrains_skiko_redrawer_MetalRedrawer_endRendering(
-    JNIEnv * env, jobject redrawer, jlong handle)
-{
-    objc_autoreleasePoolPop((void*)handle);
-}
-
 JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_redrawer_MetalRedrawer_createMetalDevice(
     JNIEnv *env, jobject redrawer, jlong windowPtr, jboolean transparency, jlong adapterPtr, jlong platformInfoPtr)
 {