android: Provide global database helper instance

src/frontends/android/app/src/main/java/org/strongswan/android/data/DatabaseHelper.java

@@ -77,7 +77,7 @@ public class DatabaseHelper extends SQLiteOpenHelper
 		TABLES.add(TABLE_VPN_PROFILE);
 	}
 
-	DatabaseHelper(Context context)
+	public DatabaseHelper(Context context)
 	{
 		super(context, DATABASE_NAME, null, DATABASE_VERSION);
 	}

src/frontends/android/app/src/main/java/org/strongswan/android/data/VpnProfileSource.java

@@ -35,7 +35,7 @@ public class VpnProfileSource implements VpnProfileDataSource
 	{
 		mManagedConfigurationService = StrongSwanApplication.getInstance().getManagedConfigurationService();
 
-		vpnProfileSqlDataSource = new VpnProfileSqlDataSource(context);
+		vpnProfileSqlDataSource = new VpnProfileSqlDataSource();
 
 		dataSources.add(vpnProfileSqlDataSource);
 		dataSources.add(new VpnProfileManagedDataSource(context));

src/frontends/android/app/src/main/java/org/strongswan/android/data/VpnProfileSqlDataSource.java

@@ -19,38 +19,36 @@
 package org.strongswan.android.data;
 
 import android.content.ContentValues;
-import android.content.Context;
 import android.database.Cursor;
 import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
 
+import org.strongswan.android.logic.StrongSwanApplication;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 
 public class VpnProfileSqlDataSource implements VpnProfileDataSource
 {
-	private DatabaseHelper mDbHelper;
+	private final DatabaseHelper mDbHelper;
+
 	private SQLiteDatabase mDatabase;
-	private final Context mContext;
 
 	/**
 	 * Construct a new VPN profile data source. The context is used to
 	 * open/create the database.
-	 *
-	 * @param context context used to access the database
 	 */
-	public VpnProfileSqlDataSource(Context context)
+	public VpnProfileSqlDataSource()
 	{
-		this.mContext = context;
+		mDbHelper = StrongSwanApplication.getInstance().getDatabaseHelper();
 	}
 
 	@Override
 	public VpnProfileDataSource open() throws SQLException
 	{
-		if (mDbHelper == null)
+		if (mDatabase == null)
 		{
-			mDbHelper = new DatabaseHelper(mContext);
 			mDatabase = mDbHelper.getWritableDatabase();
 		}
 		return this;
@@ -59,10 +57,9 @@ public class VpnProfileSqlDataSource implements VpnProfileDataSource
 	@Override
 	public void close()
 	{
-		if (mDbHelper != null)
+		if (mDatabase != null)
 		{
-			mDbHelper.close();
+			mDatabase = null;
-			mDbHelper = null;
 		}
 	}
 

src/frontends/android/app/src/main/java/org/strongswan/android/logic/StrongSwanApplication.java

@@ -26,6 +26,7 @@ import android.os.Handler;
 import android.os.Looper;
 import android.util.Log;
 
+import org.strongswan.android.data.DatabaseHelper;
 import org.strongswan.android.data.ManagedConfigurationService;
 import org.strongswan.android.security.LocalCertificateKeyStoreProvider;
 import org.strongswan.android.utils.Constants;
@@ -56,6 +57,8 @@ public class StrongSwanApplication extends Application implements DefaultLifecyc
 
 	private ManagedConfigurationService mManagedConfigurationService;
 
+	private DatabaseHelper mDatabaseHelper;
+
 	private final BroadcastReceiver mRestrictionsReceiver = new BroadcastReceiver()
 	{
 		@Override
@@ -78,6 +81,8 @@ public class StrongSwanApplication extends Application implements DefaultLifecyc
 		StrongSwanApplication.mContext = getApplicationContext();
 		StrongSwanApplication.mInstance = this;
 
+		mDatabaseHelper = new DatabaseHelper(mContext);
+
 		mManagedConfigurationService = new ManagedConfigurationService(mContext);
 		ProcessLifecycleOwner.get().getLifecycle().addObserver(this);
 	}
@@ -162,6 +167,14 @@ public class StrongSwanApplication extends Application implements DefaultLifecyc
 		return mManagedConfigurationService;
 	}
 
+	/**
+	 * @return the application's database helper used to access its SQLite database
+	 */
+	public DatabaseHelper getDatabaseHelper()
+	{
+		return mDatabaseHelper;
+	}
+
 	/*
 	 * The libraries are extracted to /data/data/org.strongswan.android/...
 	 * during installation.  On newer releases most are loaded in JNI_OnLoad.