From 9bebf1d32f2b0449d282d9fcd86dca1a94784ccf Mon Sep 17 00:00:00 2001
From: cpfeiffer <cpfeiffer@users.noreply.github.com>
Date: Thu, 24 Nov 2016 21:11:28 +0100
Subject: [PATCH] When memory is really low, free up some memory #436

(although we probably can't save much)
---
 .../gadgetbridge/GBApplication.java           | 28 +++++++++++++++++++
 .../gadgetbridge/database/DBHelper.java       | 10 +++++++
 2 files changed, 38 insertions(+)

diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java
index 984f03ec..c3e7d447 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java
@@ -22,6 +22,7 @@ import android.util.TypedValue;
 import java.io.File;
 import java.io.IOException;
 import java.util.HashSet;
+import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -32,9 +33,11 @@ import nodomain.freeyourgadget.gadgetbridge.database.DBHelper;
 import nodomain.freeyourgadget.gadgetbridge.database.DBOpenHelper;
 import nodomain.freeyourgadget.gadgetbridge.devices.DeviceManager;
 import nodomain.freeyourgadget.gadgetbridge.entities.DaoMaster;
+import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
 import nodomain.freeyourgadget.gadgetbridge.impl.GBDeviceService;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivityUser;
 import nodomain.freeyourgadget.gadgetbridge.model.DeviceService;
+import nodomain.freeyourgadget.gadgetbridge.util.DeviceHelper;
 import nodomain.freeyourgadget.gadgetbridge.util.FileUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.GBPrefs;
@@ -131,6 +134,31 @@ public class GBApplication extends Application {
         }
     }
 
+    @Override
+    public void onTrimMemory(int level) {
+        super.onTrimMemory(level);
+        if (level >= TRIM_MEMORY_BACKGROUND) {
+            if (!hasBusyDevice()) {
+                DBHelper.clearSession();
+            }
+        }
+    }
+
+    /**
+     * Returns true if at least a single device is busy, e.g synchronizing activity data
+     * or something similar.
+     * Note: busy is not the same as connected or initialized!
+     */
+    private boolean hasBusyDevice() {
+        List<GBDevice> devices = getDeviceManager().getDevices();
+        for (GBDevice device: devices) {
+            if (device.isBusy()) {
+                return true;
+            }
+        }
+        return true;
+    }
+
     public static void setupLogging(boolean enabled) {
         logging.setupLogging(enabled);
     }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/database/DBHelper.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/database/DBHelper.java
index 0794131d..3ec0ec6c 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/database/DBHelper.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/database/DBHelper.java
@@ -26,6 +26,7 @@ import de.greenrobot.dao.query.Query;
 import de.greenrobot.dao.query.QueryBuilder;
 import de.greenrobot.dao.query.WhereCondition;
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
+import nodomain.freeyourgadget.gadgetbridge.GBException;
 import nodomain.freeyourgadget.gadgetbridge.devices.AbstractSampleProvider;
 import nodomain.freeyourgadget.gadgetbridge.devices.DeviceCoordinator;
 import nodomain.freeyourgadget.gadgetbridge.devices.pebble.PebbleHealthSampleProvider;
@@ -685,4 +686,13 @@ public class DBHelper {
         }
         return cursor.getInt(columnIndex);
     }
+
+    public static void clearSession() {
+        try (DBHandler dbHandler = GBApplication.acquireDB()) {
+            DaoSession session = dbHandler.getDaoSession();
+            session.clear();
+        } catch (Exception e) {
+            LOG.warn("Unable to acquire database to clear the session", e);
+        }
+    }
 }