From 94dd0a266141a7464f8ed24b1e0c964ce3c00e75 Mon Sep 17 00:00:00 2001
From: akwizgran <michael@briarproject.org>
Date: Thu, 6 Aug 2020 14:53:05 +0100
Subject: [PATCH] Hold a wake lock while scheduled tasks are running.

---
 .../bramble/system/AndroidTaskScheduler.java  | 28 ++++++++++++++++---
 .../system/AndroidTaskSchedulerModule.java    |  8 ++++--
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskScheduler.java b/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskScheduler.java
index 074f57632..3b8ade660 100644
--- a/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskScheduler.java
+++ b/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskScheduler.java
@@ -11,6 +11,8 @@ import android.os.SystemClock;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.system.AlarmListener;
+import org.briarproject.bramble.api.system.AndroidWakeLock;
+import org.briarproject.bramble.api.system.AndroidWakeLockFactory;
 import org.briarproject.bramble.api.system.TaskScheduler;
 
 import java.util.ArrayList;
@@ -51,6 +53,7 @@ class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
 	private static final long ALARM_MS = INTERVAL_FIFTEEN_MINUTES;
 
 	private final Application app;
+	private final AndroidWakeLockFactory wakeLockFactory;
 	private final ScheduledExecutorService scheduledExecutorService;
 	private final AlarmManager alarmManager;
 
@@ -59,8 +62,10 @@ class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
 	private final Queue<ScheduledTask> tasks = new PriorityQueue<>();
 
 	AndroidTaskScheduler(Application app,
+			AndroidWakeLockFactory wakeLockFactory,
 			ScheduledExecutorService scheduledExecutorService) {
 		this.app = app;
+		this.wakeLockFactory = wakeLockFactory;
 		this.scheduledExecutorService = scheduledExecutorService;
 		alarmManager = (AlarmManager)
 				requireNonNull(app.getSystemService(ALARM_SERVICE));
@@ -83,7 +88,8 @@ class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
 			TimeUnit unit) {
 		long now = SystemClock.elapsedRealtime();
 		long dueMillis = now + MILLISECONDS.convert(delay, unit);
-		ScheduledTask s = new ScheduledTask(task, executor, dueMillis);
+		Runnable wakeful = createWakefulTask(task, executor);
+		ScheduledTask s = new ScheduledTask(wakeful, dueMillis);
 		if (dueMillis <= now) {
 			scheduledExecutorService.execute(s);
 		} else {
@@ -118,6 +124,21 @@ class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
 		}
 	}
 
+	private Runnable createWakefulTask(Runnable task, Executor executor) {
+		// Hold a wake lock from before we submit the task until after it runs
+		AndroidWakeLock wakeLock = wakeLockFactory.createWakeLock();
+		return () -> {
+			wakeLock.acquire();
+			executor.execute(() -> {
+				try {
+					task.run();
+				} finally {
+					wakeLock.release();
+				}
+			});
+		};
+	}
+
 	private void runDueTasks() {
 		long now = SystemClock.elapsedRealtime();
 		List<ScheduledTask> due = new ArrayList<>();
@@ -177,9 +198,8 @@ class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
 
 		private final long dueMillis;
 
-		public ScheduledTask(Runnable runnable, Executor executor,
-				long dueMillis) {
-			super(() -> executor.execute(runnable), null);
+		public ScheduledTask(Runnable runnable, long dueMillis) {
+			super(runnable, null);
 			this.dueMillis = dueMillis;
 		}
 
diff --git a/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskSchedulerModule.java b/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskSchedulerModule.java
index 88fc77ff9..fd47e7523 100644
--- a/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskSchedulerModule.java
+++ b/bramble-android/src/main/java/org/briarproject/bramble/system/AndroidTaskSchedulerModule.java
@@ -4,6 +4,7 @@ import android.app.Application;
 
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.system.AlarmListener;
+import org.briarproject.bramble.api.system.AndroidWakeLockFactory;
 import org.briarproject.bramble.api.system.TaskScheduler;
 
 import java.util.concurrent.RejectedExecutionHandler;
@@ -36,10 +37,11 @@ public class AndroidTaskSchedulerModule {
 	@Provides
 	@Singleton
 	AndroidTaskScheduler provideAndroidTaskScheduler(
-			LifecycleManager lifecycleManager, Application app) {
+			LifecycleManager lifecycleManager, Application app,
+			AndroidWakeLockFactory wakeLockFactory) {
 		lifecycleManager.registerForShutdown(scheduledExecutorService);
-		AndroidTaskScheduler scheduler =
-				new AndroidTaskScheduler(app, scheduledExecutorService);
+		AndroidTaskScheduler scheduler = new AndroidTaskScheduler(app,
+				wakeLockFactory, scheduledExecutorService);
 		lifecycleManager.registerService(scheduler);
 		return scheduler;
 	}