Fix ANRs when shutting down the engine

Author: m4gr3d

platform/android/java/lib/src/main/java/org/godotengine/godot/Godot.kt

@@ -108,6 +108,8 @@ class Godot private constructor(val context: Context) {
 			}
 		}
 
+		private const val EXIT_RENDERER_TIMEOUT_IN_MS = 750L
+
 		// Supported build flavors
 		private const val EDITOR_FLAVOR = "editor"
 		private const val TEMPLATE_FLAVOR = "template"
@@ -748,7 +750,12 @@ class Godot private constructor(val context: Context) {
 			plugin.onMainDestroy()
 		}
 
-		renderView?.onActivityDestroyed()
+		if (renderView?.blockingExitRenderer(EXIT_RENDERER_TIMEOUT_IN_MS) != true) {
+			Log.w(TAG, "Unable to exit the renderer within $EXIT_RENDERER_TIMEOUT_IN_MS ms... Force quitting the process.")
+			onGodotTerminating()
+			forceQuit(0)
+		}
+
 		this.primaryHost = null
 	}
 

platform/android/java/lib/src/main/java/org/godotengine/godot/GodotGLRenderView.java

@@ -132,8 +132,8 @@ public void onActivityStarted() {
 	}
 
 	@Override
-	public void onActivityDestroyed() {
-		requestRenderThreadExitAndWait();
+	public boolean blockingExitRenderer(long blockingTimeInMs) {
+		return requestRenderThreadExitAndWait(blockingTimeInMs);
 	}
 
 	@Override

platform/android/java/lib/src/main/java/org/godotengine/godot/GodotRenderView.java

@@ -55,7 +55,7 @@ public interface GodotRenderView {
 
 	void onActivityStarted();
 
-	void onActivityDestroyed();
+	boolean blockingExitRenderer(long blockingTimeInMs);
 
 	GodotInputHandler getInputHandler();
 

platform/android/java/lib/src/main/java/org/godotengine/godot/GodotVulkanRenderView.java

@@ -117,8 +117,8 @@ public void onActivityResumed() {
 	}
 
 	@Override
-	public void onActivityDestroyed() {
-		requestRenderThreadExitAndWait();
+	public boolean blockingExitRenderer(long blockingTimeInMs) {
+		return requestRenderThreadExitAndWait(blockingTimeInMs);
 	}
 
 	@Override

platform/android/java/lib/src/main/java/org/godotengine/godot/gl/GLSurfaceView.java

@@ -604,6 +604,18 @@ protected final void requestRenderThreadExitAndWait() {
 			mGLThread.requestExitAndWait();
 		}
 	}
+
+	/**
+	 * Requests the render thread to exit and block up to the given timeInMs until it's done.
+	 *
+	 * @return true if the thread exited, false otherwise.
+	 */
+	protected final boolean requestRenderThreadExitAndWait(long timeInMs) {
+		if (mGLThread != null) {
+			return mGLThread.requestExitAndWait(timeInMs);
+		}
+		return false;
+	}
 	// -- GODOT end --
 
 	/**
@@ -1796,6 +1808,23 @@ public void requestExitAndWait() {
 			}
 		}
 
+		public boolean requestExitAndWait(long timeInMs) {
+			// Don't call this from GLThread thread or it is a guaranteed deadlock!
+			synchronized(sGLThreadManager) {
+				mShouldExit = true;
+				sGLThreadManager.notifyAll();
+				if (!mExited) {
+					try {
+						sGLThreadManager.wait(timeInMs);
+					} catch (InterruptedException ex) {
+						Thread.currentThread().interrupt();
+					}
+				}
+
+				return mExited;
+			}
+		}
+
 		public void requestReleaseEglContextLocked() {
 			mShouldReleaseEglContext = true;
 			sGLThreadManager.notifyAll();

platform/android/java/lib/src/main/java/org/godotengine/godot/vulkan/VkSurfaceView.kt

@@ -119,6 +119,15 @@ open internal class VkSurfaceView(context: Context) : SurfaceView(context), Surf
 		vkThread.requestExitAndWait()
 	}
 
+	/**
+	 * Requests the render thread to exit and block up to the given [timeInMs] until it's done.
+	 *
+	 * @return true if the thread exited, false otherwise.
+	 */
+	fun requestRenderThreadExitAndWait(timeInMs: Long): Boolean {
+		return vkThread.requestExitAndWait(timeInMs)
+	}
+
 	override fun surfaceChanged(holder: SurfaceHolder, format: Int, width: Int, height: Int) {
 		vkThread.onSurfaceChanged(width, height)
 	}

platform/android/java/lib/src/main/java/org/godotengine/godot/vulkan/VkThread.kt

@@ -32,6 +32,7 @@
 package org.godotengine.godot.vulkan
 
 import android.util.Log
+import java.util.concurrent.TimeUnit
 import java.util.concurrent.locks.ReentrantLock
 import kotlin.concurrent.withLock
 
@@ -104,13 +105,37 @@ internal class VkThread(private val vkSurfaceView: VkSurfaceView, private val vk
 				try {
 					Log.i(TAG, "Waiting on exit for $name")
 					lockCondition.await()
-				} catch (ex: InterruptedException) {
+				} catch (_: InterruptedException) {
 					currentThread().interrupt()
 				}
 			}
 		}
 	}
 
+	/**
+	 * Request the thread to exit and block up to the given [timeInMs] until it's done.
+	 *
+	 * @return true if the thread exited, false otherwise.
+	 */
+	fun requestExitAndWait(timeInMs: Long): Boolean {
+		lock.withLock {
+			shouldExit = true
+			lockCondition.signalAll()
+
+			var remainingTimeInNanos = TimeUnit.MILLISECONDS.toNanos(timeInMs)
+			while (!exited && remainingTimeInNanos > 0) {
+				try {
+					Log.i(TAG, "Waiting on exit for $name for $remainingTimeInNanos")
+					remainingTimeInNanos = lockCondition.awaitNanos(remainingTimeInNanos)
+				} catch (_: InterruptedException) {
+					currentThread().interrupt()
+				}
+			}
+
+			return exited
+		}
+	}
+
 	/**
 	 * Invoked when the app resumes.
 	 */