Restart push/poll after device idle mode (Doze) has been left

k9mail/src/main/java/com/fsck/k9/K9.java

@@ -38,6 +38,7 @@ import com.fsck.k9.mail.Message;
 import com.fsck.k9.mail.internet.BinaryTempFileBody;
 import com.fsck.k9.mail.ssl.LocalKeyStore;
 import com.fsck.k9.mailstore.LocalStore;
+import com.fsck.k9.power.DeviceIdleManager;
 import com.fsck.k9.preferences.Storage;
 import com.fsck.k9.preferences.StorageEditor;
 import com.fsck.k9.provider.UnreadWidgetProvider;
@@ -353,10 +354,22 @@ public class K9 extends Application {
      * whether any accounts are configured.
      */
     public static void setServicesEnabled(Context context) {
-        int acctLength = Preferences.getPreferences(context).getAvailableAccounts().size();
+        Context appContext = context.getApplicationContext();
+        int acctLength = Preferences.getPreferences(appContext).getAvailableAccounts().size();
+        boolean enable = acctLength > 0;
 
-        setServicesEnabled(context, acctLength > 0, null);
+        setServicesEnabled(appContext, enable, null);
 
+        updateDeviceIdleReceiver(appContext, enable);
+    }
+
+    private static void updateDeviceIdleReceiver(Context context, boolean enable) {
+        DeviceIdleManager deviceIdleManager = DeviceIdleManager.getInstance(context);
+        if (enable) {
+            deviceIdleManager.registerReceiver();
+        } else {
+            deviceIdleManager.unregisterReceiver();
+        }
     }
 
     private static void setServicesEnabled(Context context, boolean enabled, Integer wakeLockId) {

k9mail/src/main/java/com/fsck/k9/power/DeviceIdleManager.java

@@ -0,0 +1,84 @@
+package com.fsck.k9.power;
+
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.content.IntentFilter;
+import android.os.Build;
+import android.os.PowerManager;
+
+import timber.log.Timber;
+
+
+public abstract class DeviceIdleManager {
+    private static DeviceIdleManager instance;
+
+
+    public static synchronized DeviceIdleManager getInstance(Context context) {
+        if (instance == null) {
+            DozeChecker dozeChecker = new DozeChecker(context);
+            if (dozeChecker.isDeviceIdleModeSupported() && !dozeChecker.isAppWhitelisted()) {
+                instance = RealDeviceIdleManager.newInstance(context);
+            } else {
+                instance = new NoOpDeviceIdleManager();
+            }
+        }
+        return instance;
+    }
+
+    private DeviceIdleManager() {
+    }
+
+    public abstract void registerReceiver();
+    public abstract void unregisterReceiver();
+
+
+    static class NoOpDeviceIdleManager extends DeviceIdleManager {
+        @Override
+        public void registerReceiver() {
+            // Do nothing
+        }
+
+        @Override
+        public void unregisterReceiver() {
+            // Do nothing
+        }
+    }
+
+    @TargetApi(Build.VERSION_CODES.M)
+    static class RealDeviceIdleManager extends DeviceIdleManager {
+        private final Context context;
+        private final DeviceIdleReceiver deviceIdleReceiver;
+        private final IntentFilter intentFilter;
+        private boolean registered;
+
+
+        static RealDeviceIdleManager newInstance(Context context) {
+            Context appContext = context.getApplicationContext();
+            return new RealDeviceIdleManager(appContext);
+        }
+
+        private RealDeviceIdleManager(Context context) {
+            this.context = context;
+            PowerManager powerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
+            deviceIdleReceiver = new DeviceIdleReceiver(powerManager);
+            intentFilter = new IntentFilter(PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED);
+        }
+
+        @Override
+        public void registerReceiver() {
+            Timber.v("Registering DeviceIdleReceiver");
+            registered = true;
+            context.registerReceiver(deviceIdleReceiver, intentFilter);
+        }
+
+        @Override
+        public void unregisterReceiver() {
+            Timber.v("Unregistering DeviceIdleReceiver");
+            if (registered) {
+                context.unregisterReceiver(deviceIdleReceiver);
+                registered = false;
+            }
+        }
+    }
+}

k9mail/src/main/java/com/fsck/k9/power/DeviceIdleReceiver.java

@@ -0,0 +1,33 @@
+package com.fsck.k9.power;
+
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Build;
+import android.os.PowerManager;
+import android.support.annotation.RequiresApi;
+
+import com.fsck.k9.service.MailService;
+import timber.log.Timber;
+
+
+@RequiresApi(api = Build.VERSION_CODES.M)
+class DeviceIdleReceiver extends BroadcastReceiver {
+    private final PowerManager powerManager;
+
+
+    DeviceIdleReceiver(PowerManager powerManager) {
+        this.powerManager = powerManager;
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        boolean deviceInIdleMode = powerManager.isDeviceIdleMode();
+        Timber.v("Device idle mode changed. Idle: %b", deviceInIdleMode);
+
+        if (!deviceInIdleMode) {
+            MailService.actionReset(context, null);
+        }
+    }
+}