Add basic support for exporting the database

app/src/main/AndroidManifest.xml

@@ -5,6 +5,7 @@
     <uses-permission android:name="android.permission.CAMERA"/>
     <uses-permission android:name="android.permission.USE_FINGERPRINT" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 
     <application
         android:allowBackup="true"

app/src/main/java/me/impy/aegis/IntroActivity.java

@@ -171,7 +171,7 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
                 _databaseFile.setContent(result.Data);
                 _databaseFile.setCryptParameters(result.Parameters);
             }
-            _databaseFile.save(getApplicationContext(), DatabaseManager.FILENAME);
+            DatabaseManager.save(getApplicationContext(), _databaseFile);
         } catch (Exception e) {
             setException(e);
             return;

app/src/main/java/me/impy/aegis/MainActivity.java

@@ -3,11 +3,13 @@ package me.impy.aegis;
 import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.pm.ShortcutInfo;
 import android.content.pm.ShortcutManager;
 import android.graphics.drawable.Icon;
+import android.media.MediaScannerConnection;
 import android.os.Build;
 import android.preference.PreferenceManager;
 import android.support.design.widget.BottomSheetDialog;
@@ -46,6 +48,7 @@ public class MainActivity extends AppCompatActivity {
     private static final int CODE_DO_INTRO = 2;
     private static final int CODE_DECRYPT = 3;
     private static final int CODE_IMPORT = 4;
+    private static final int CODE_PREFERENCES = 5;
 
     private KeyProfileAdapter _keyProfileAdapter;
     private ArrayList<KeyProfile> _keyProfiles;
@@ -140,6 +143,54 @@ public class MainActivity extends AppCompatActivity {
             case CODE_IMPORT:
                 onImportResult(resultCode, data);
                 break;
+            case CODE_PREFERENCES:
+                onPreferencesResult(resultCode, data);
+                break;
+        }
+    }
+
+    private void onPreferencesResult(int resultCode, Intent data) {
+        if (resultCode != RESULT_OK) {
+            return;
+        }
+
+        // TODO: create a custom layout to show a message AND a checkbox
+        int action = data.getIntExtra("action", -1);
+        switch (action) {
+            case PreferencesActivity.ACTION_EXPORT:
+                final boolean[] checked = {true};
+                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this)
+                        .setTitle("Export the database")
+                        .setPositiveButton(android.R.string.ok, (dialog, which) -> {
+                            String filename;
+                            try {
+                                filename = _db.export(checked[0]);
+                            } catch (Exception e) {
+                                e.printStackTrace();
+                                Toast.makeText(this, "An error occurred while trying to export the database", Toast.LENGTH_SHORT).show();
+                                return;
+                            }
+
+                            // make sure the new file is visible
+                            MediaScannerConnection.scanFile(this, new String[]{filename}, null, null);
+
+                            Toast.makeText(this, "The database has been exported to: " + filename, Toast.LENGTH_SHORT).show();
+                        })
+                        .setNegativeButton(android.R.string.cancel, null);
+                if (_db.getFile().isEncrypted()) {
+                    final String[] items = {"Keep the database encrypted"};
+                    final boolean[] checkedItems = {true};
+                    builder.setMultiChoiceItems(items, checkedItems, new DialogInterface.OnMultiChoiceClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int index, boolean isChecked) {
+                            checked[0] = isChecked;
+                        }
+                    });
+                } else {
+                    builder.setMessage("This action will export the database out of Android's private storage.");
+                }
+                builder.show();
+                break;
         }
     }
 
@@ -371,7 +422,7 @@ public class MainActivity extends AppCompatActivity {
         switch (item.getItemId()) {
             case R.id.action_settings:
                 Intent preferencesActivity = new Intent(this, PreferencesActivity.class);
-                startActivity(preferencesActivity);
+                startActivityForResult(preferencesActivity, CODE_PREFERENCES);
                 return true;
             case R.id.action_import:
                 Intent intent = new Intent(Intent.ACTION_GET_CONTENT);

app/src/main/java/me/impy/aegis/PreferencesActivity.java

@@ -1,5 +1,7 @@
 package me.impy.aegis;
 
+import android.app.Activity;
+import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 import android.preference.Preference;
@@ -9,13 +11,14 @@ import android.support.v7.app.AppCompatActivity;
 import android.widget.Toast;
 
 public class PreferencesActivity extends AppCompatActivity {
+    public static final int ACTION_EXPORT = 0;
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        SharedPreferences mySharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
+        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
-        if (mySharedPreferences.getBoolean("pref_night_mode", false)) {
+        if (preferences.getBoolean("pref_night_mode", false)) {
             setTheme(R.style.AppTheme_Dark);
         } else {
             setTheme(R.style.AppTheme_Default);
@@ -29,7 +32,6 @@ public class PreferencesActivity extends AppCompatActivity {
         @Override
         public void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
-
             addPreferencesFromResource(R.xml.preferences);
 
             final Preference nightModePreference = findPreference("pref_night_mode");
@@ -40,6 +42,20 @@ public class PreferencesActivity extends AppCompatActivity {
                     return true;
                 }
             });
+
+            Preference exportPreference = findPreference("pref_export");
+            exportPreference.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+                @Override
+                public boolean onPreferenceClick(Preference preference) {
+                    Intent intent = new Intent();
+                    intent.putExtra("action", ACTION_EXPORT);
+
+                    Activity activity = getActivity();
+                    activity.setResult(RESULT_OK, intent);
+                    activity.finish();
+                    return true;
+                }
+            });
         }
     }
 }

app/src/main/java/me/impy/aegis/db/DatabaseFile.java

@@ -5,6 +5,7 @@ import android.content.Context;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
+import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -116,37 +117,6 @@ public class DatabaseFile {
         return !_slots.isEmpty() && _cryptParameters != null;
     }
 
-    public void save(Context context, String filename) throws IOException {
-        byte[] data = serialize();
-
-        FileOutputStream file = context.openFileOutput(filename, Context.MODE_PRIVATE);
-        file.write(data);
-        file.close();
-    }
-
-    public static DatabaseFile load(Context context, String filename) throws Exception {
-        byte[] bytes;
-        FileInputStream file = null;
-
-        try {
-            file = context.openFileInput(filename);
-            DataInputStream stream = new DataInputStream(file);
-            bytes = new byte[(int) file.getChannel().size()];
-            stream.readFully(bytes);
-            stream.close();
-        } finally {
-            // always close the file
-            // there is no need to close the DataInputStream
-            if (file != null) {
-                file.close();
-            }
-        }
-
-        DatabaseFile db = new DatabaseFile();
-        db.deserialize(bytes);
-        return db;
-    }
-
     private static void writeSection(DataOutputStream stream, byte id, byte[] data) throws IOException {
         stream.write(id);
 

app/src/main/java/me/impy/aegis/db/DatabaseManager.java

@@ -1,16 +1,23 @@
 package me.impy.aegis.db;
 
 import android.content.Context;
+import android.os.Environment;
 
+import java.io.DataInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
 import java.util.List;
 
-import me.impy.aegis.KeyProfile;
 import me.impy.aegis.crypto.CryptParameters;
 import me.impy.aegis.crypto.CryptResult;
 import me.impy.aegis.crypto.MasterKey;
 
 public class DatabaseManager {
-    public static final String FILENAME = "aegis.db";
+    private static final String FILENAME = "aegis.db";
+    private static final String FILENAME_EXPORT = "aegis_export.db";
+    private static final String FILENAME_EXPORT_PLAIN = "aegis_export.json";
 
     private MasterKey _key;
     private DatabaseFile _file;
@@ -22,11 +29,30 @@ public class DatabaseManager {
     }
 
     public void load() throws Exception {
-        _file = DatabaseFile.load(_context, FILENAME);
+        byte[] fileBytes;
+        FileInputStream file = null;
+
+        try {
+            file = _context.openFileInput(FILENAME);
+            fileBytes = new byte[(int) file.getChannel().size()];
+            DataInputStream stream = new DataInputStream(file);
+            stream.readFully(fileBytes);
+            stream.close();
+        } finally {
+            // always close the file stream
+            // there is no need to close the DataInputStream
+            if (file != null) {
+                file.close();
+            }
+        }
+
+        _file = new DatabaseFile();
+        _file.deserialize(fileBytes);
+
         if (!_file.isEncrypted()) {
-            byte[] bytes = _file.getContent();
+            byte[] contentBytes = _file.getContent();
             _db = new Database();
-            _db.deserialize(bytes);
+            _db.deserialize(contentBytes);
         }
     }
 
@@ -40,17 +66,64 @@ public class DatabaseManager {
         _key = key;
     }
 
+    public static void save(Context context, DatabaseFile file) throws IOException {
+        byte[] bytes = file.serialize();
+
+        FileOutputStream stream = null;
+        try {
+            stream = context.openFileOutput(FILENAME, Context.MODE_PRIVATE);
+            stream.write(bytes);
+        } finally {
+            // always close the file stream
+            if (stream != null) {
+                stream.close();
+            }
+        }
+    }
+
     public void save() throws Exception {
         assertDecrypted();
-        byte[] bytes = _db.serialize();
+        byte[] dbBytes = _db.serialize();
         if (!_file.isEncrypted()) {
-            _file.setContent(bytes);
+            _file.setContent(dbBytes);
         } else {
+            CryptResult result = _key.encrypt(dbBytes);
+            _file.setContent(result.Data);
+            _file.setCryptParameters(result.Parameters);
+        }
+        save(_context, _file);
+    }
+
+    public String export(boolean encrypt) throws Exception {
+        assertDecrypted();
+        byte[] bytes = _db.serialize();
+        encrypt = encrypt && getFile().isEncrypted();
+        if (encrypt) {
             CryptResult result = _key.encrypt(bytes);
             _file.setContent(result.Data);
             _file.setCryptParameters(result.Parameters);
+            bytes = _file.serialize();
         }
-        _file.save(_context, FILENAME);
+
+        File file;
+        FileOutputStream stream = null;
+        try {
+            File dir = new File(Environment.getExternalStorageDirectory(), "Aegis");
+            if (!dir.exists() && !dir.mkdirs()) {
+                throw new IOException("error creating external storage directory");
+            }
+
+            file = new File(dir.getAbsolutePath(), encrypt ? FILENAME_EXPORT : FILENAME_EXPORT_PLAIN);
+            stream = new FileOutputStream(file);
+            stream.write(bytes);
+        } finally {
+            // always close the file stream
+            if (stream != null) {
+                stream.close();
+            }
+        }
+
+        return file.getAbsolutePath();
     }
 
     public void addKey(DatabaseEntry entry) throws Exception {

app/src/main/res/xml/preferences.xml

@@ -13,4 +13,10 @@
         android:key="pref_issuer"
         android:title="@string/pref_issuers"
         android:summary="@string/pref_issuers_description"/>
+
+    <Preference
+        android:key="pref_export"
+        android:title="Export"
+        android:summary="Export the database"/>
+
 </PreferenceScreen>