Imports basically work now, although there may be some issues if the user switches language between export and import.

app/src/main/java/ch/dissem/apps/abit/SettingsFragment.kt

@@ -16,9 +16,11 @@
 
 package ch.dissem.apps.abit
 
+import android.app.Activity
 import android.content.Context
 import android.content.Intent
 import android.content.SharedPreferences
+import android.net.Uri
 import android.os.Bundle
 import android.preference.PreferenceManager
 import android.support.v4.content.FileProvider.getUriForFile
@@ -30,21 +32,23 @@ import ch.dissem.apps.abit.synchronization.SyncAdapter
 import ch.dissem.apps.abit.util.Constants.PREFERENCE_SERVER_POW
 import ch.dissem.apps.abit.util.Constants.PREFERENCE_TRUSTED_NODE
 import ch.dissem.apps.abit.util.Preferences
+import ch.dissem.bitmessage.entity.valueobject.Label
 import ch.dissem.bitmessage.exports.ContactExport
 import ch.dissem.bitmessage.exports.MessageExport
 import ch.dissem.bitmessage.utils.UnixTime
+import com.beust.klaxon.JsonArray
+import com.beust.klaxon.Parser
 import com.mikepenz.aboutlibraries.Libs
 import com.mikepenz.aboutlibraries.LibsBuilder
 import org.jetbrains.anko.doAsync
 import org.jetbrains.anko.support.v4.indeterminateProgressDialog
 import org.jetbrains.anko.uiThread
-import org.slf4j.LoggerFactory
 import java.io.File
 import java.io.FileOutputStream
 import java.util.zip.ZipEntry
+import java.util.zip.ZipInputStream
 import java.util.zip.ZipOutputStream
 
-
 /**
  * @author Christian Basler
  */
@@ -128,7 +132,7 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
                 intent.type = "application/zip"
                 intent.putExtra(Intent.EXTRA_SUBJECT, "abit-export.zip")
                 intent.putExtra(Intent.EXTRA_STREAM, contentUri)
-                startActivityForResult(Intent.createChooser(intent, ""), 0)
+                startActivityForResult(Intent.createChooser(intent, ""), WRITE_EXPORT_REQUEST_CODE)
                 uiThread {
                     dialog.dismiss()
                 }
@@ -136,6 +140,15 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
             return@OnPreferenceClickListener true
         }
 
+        findPreference("import")?.onPreferenceClickListener = Preference.OnPreferenceClickListener {
+            val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
+            intent.addCategory(Intent.CATEGORY_OPENABLE)
+            intent.type = "application/zip"
+
+            startActivityForResult(intent, READ_IMPORT_REQUEST_CODE)
+            return@OnPreferenceClickListener true
+        }
+
         findPreference("status").onPreferenceClickListener = Preference.OnPreferenceClickListener {
             val activity = activity as MainActivity
             if (activity.hasDetailPane()) {
@@ -147,8 +160,57 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
         }
     }
 
+    private fun processEntry(zipFile: Uri, entry: String, processor: (JsonArray<*>) -> Unit) {
+        ZipInputStream(context.contentResolver.openInputStream(zipFile)).use { zip ->
+            var nextEntry = zip.nextEntry
+            while (nextEntry != null) {
+                if (nextEntry.name == entry) {
+                    processor(Parser().parse(zip) as JsonArray<*>)
+                }
+                nextEntry = zip.nextEntry
+            }
+        }
+    }
+
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
-        Preferences.cleanupExportDirectory(context)
+        when (requestCode) {
+            WRITE_EXPORT_REQUEST_CODE -> Preferences.cleanupExportDirectory(context)
+            READ_IMPORT_REQUEST_CODE -> {
+                if (resultCode == Activity.RESULT_OK && data?.data != null) {
+                    val dialog = indeterminateProgressDialog(R.string.import_data_summary, R.string.import_data)
+                    doAsync {
+                        val ctx = Singleton.getBitmessageContext(context)
+                        val labels = mutableMapOf<String, Label>()
+                        val zipFile = data.data
+
+                        processEntry(zipFile, "contacts.json") { json ->
+                            ContactExport.importContacts(json).forEach { contact ->
+                                ctx.addresses.save(contact)
+                            }
+                        }
+                        ctx.messages.getLabels().forEach { label ->
+                            labels[label.toString()] = label
+                        }
+                        processEntry(zipFile, "labels.json") { json ->
+                            MessageExport.importLabels(json).forEach { label ->
+                                if (!labels.contains(label.toString())) {
+                                    ctx.messages.save(label)
+                                    labels[label.toString()] = label
+                                }
+                            }
+                        }
+                        processEntry(zipFile, "messages.json") { json ->
+                            MessageExport.importMessages(json, labels).forEach { message ->
+                                ctx.messages.save(message)
+                            }
+                        }
+                        uiThread {
+                            dialog.dismiss()
+                        }
+                    }
+                }
+            }
+        }
     }
 
     override fun onAttach(ctx: Context?) {
@@ -182,4 +244,9 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
             }
         }
     }
+
+    companion object {
+        const val WRITE_EXPORT_REQUEST_CODE = 1
+        const val READ_IMPORT_REQUEST_CODE = 2
+    }
 }

app/src/main/java/ch/dissem/apps/abit/repository/AndroidMessageRepository.java

@@ -1,428 +0,0 @@
-/*
- * Copyright 2015 Christian Basler
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package ch.dissem.apps.abit.repository;
-
-import android.content.ContentValues;
-import android.content.Context;
-import android.database.Cursor;
-import android.database.DatabaseUtils;
-import android.database.sqlite.SQLiteConstraintException;
-import android.database.sqlite.SQLiteDatabase;
-import android.support.annotation.NonNull;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.io.ByteArrayInputStream;
-import java.util.Collection;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.UUID;
-
-import ch.dissem.apps.abit.util.Labels;
-import ch.dissem.apps.abit.util.UuidUtils;
-import ch.dissem.bitmessage.entity.BitmessageAddress;
-import ch.dissem.bitmessage.entity.Plaintext;
-import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
-import ch.dissem.bitmessage.entity.valueobject.Label;
-import ch.dissem.bitmessage.ports.AbstractMessageRepository;
-import ch.dissem.bitmessage.ports.MessageRepository;
-import ch.dissem.bitmessage.utils.Encode;
-
-import static ch.dissem.apps.abit.util.UuidUtils.asUuid;
-import static ch.dissem.bitmessage.utils.Strings.hex;
-import static java.lang.String.valueOf;
-
-/**
- * {@link MessageRepository} implementation using the Android SQL API.
- */
-public class AndroidMessageRepository extends AbstractMessageRepository {
-    private static final Logger LOG = LoggerFactory.getLogger(AndroidMessageRepository.class);
-
-    public static final Label LABEL_ARCHIVE = new Label("archive", null, 0);
-
-    private static final String TABLE_NAME = "Message";
-    private static final String COLUMN_ID = "id";
-    private static final String COLUMN_IV = "iv";
-    private static final String COLUMN_TYPE = "type";
-    private static final String COLUMN_SENDER = "sender";
-    private static final String COLUMN_RECIPIENT = "recipient";
-    private static final String COLUMN_DATA = "data";
-    private static final String COLUMN_ACK_DATA = "ack_data";
-    private static final String COLUMN_SENT = "sent";
-    private static final String COLUMN_RECEIVED = "received";
-    private static final String COLUMN_STATUS = "status";
-    private static final String COLUMN_TTL = "ttl";
-    private static final String COLUMN_RETRIES = "retries";
-    private static final String COLUMN_NEXT_TRY = "next_try";
-    private static final String COLUMN_INITIAL_HASH = "initial_hash";
-    private static final String COLUMN_CONVERSATION = "conversation";
-
-    private static final String PARENTS_TABLE_NAME = "Message_Parent";
-
-    private static final String JOIN_TABLE_NAME = "Message_Label";
-    private static final String JT_COLUMN_MESSAGE = "message_id";
-    private static final String JT_COLUMN_LABEL = "label_id";
-
-    private static final String LBL_TABLE_NAME = "Label";
-    private static final String LBL_COLUMN_ID = "id";
-    private static final String LBL_COLUMN_LABEL = "label";
-    private static final String LBL_COLUMN_TYPE = "type";
-    private static final String LBL_COLUMN_COLOR = "color";
-    private static final String LBL_COLUMN_ORDER = "ord";
-    private final SqlHelper sql;
-    private final Context context;
-
-    public AndroidMessageRepository(SqlHelper sql, Context ctx) {
-        this.sql = sql;
-        this.context = ctx;
-    }
-
-    @NonNull
-    @Override
-    public List<Plaintext> findMessages(Label label) {
-        if (label == LABEL_ARCHIVE) {
-            return super.findMessages((Label) null);
-        } else {
-            return super.findMessages(label);
-        }
-    }
-
-    @NonNull
-    public List<Long> findMessageIds(Label label) {
-        if (label == LABEL_ARCHIVE) {
-            return findIds("id NOT IN (SELECT message_id FROM Message_Label)");
-        } else {
-            return findIds("id IN (SELECT message_id FROM Message_Label WHERE label_id=" + label.getId() + ")");
-        }
-    }
-
-    @NonNull
-    public List<Label> findLabels(String where) {
-        List<Label> result = new LinkedList<>();
-
-        // Define a projection that specifies which columns from the database
-        // you will actually use after this query.
-        String[] projection = {
-            LBL_COLUMN_ID,
-            LBL_COLUMN_LABEL,
-            LBL_COLUMN_TYPE,
-            LBL_COLUMN_COLOR
-        };
-
-        SQLiteDatabase db = sql.getReadableDatabase();
-        try (Cursor c = db.query(
-            LBL_TABLE_NAME, projection,
-            where,
-            null, null, null,
-            LBL_COLUMN_ORDER
-        )) {
-            while (c.moveToNext()) {
-                result.add(getLabel(c));
-            }
-        }
-        return result;
-    }
-
-    private Label getLabel(Cursor c) {
-        String typeName = c.getString(c.getColumnIndex(LBL_COLUMN_TYPE));
-        Label.Type type = typeName == null ? null : Label.Type.valueOf(typeName);
-        String text = Labels.getText(type, null, context);
-        if (text == null) {
-            text = c.getString(c.getColumnIndex(LBL_COLUMN_LABEL));
-        }
-        Label label = new Label(
-            text,
-            type,
-            c.getInt(c.getColumnIndex(LBL_COLUMN_COLOR)));
-        label.setId(c.getLong(c.getColumnIndex(LBL_COLUMN_ID)));
-        return label;
-    }
-
-    @Override
-    public int countUnread(Label label) {
-        if (label == LABEL_ARCHIVE) {
-            return 0;
-        } else if (label == null) {
-            return (int) DatabaseUtils.queryNumEntries(
-                sql.getReadableDatabase(),
-                TABLE_NAME,
-                "id IN (SELECT message_id FROM Message_Label WHERE label_id IN (SELECT id FROM Label WHERE type=?))",
-                new String[]{
-                    String.valueOf(label.getId()),
-                    Label.Type.UNREAD.name()
-                }
-            );
-        } else {
-            return (int) DatabaseUtils.queryNumEntries(
-                sql.getReadableDatabase(),
-                TABLE_NAME,
-                "        id IN (SELECT message_id FROM Message_Label WHERE label_id=?) " +
-                    "AND id IN (SELECT message_id FROM Message_Label WHERE label_id IN (SELECT id FROM Label WHERE type=?))",
-                new String[]{
-                    String.valueOf(label.getId()),
-                    Label.Type.UNREAD.name()
-                }
-            );
-        }
-    }
-
-    @NonNull
-    @Override
-    public List<UUID> findConversations(Label label) {
-        String[] projection = {
-            COLUMN_CONVERSATION,
-        };
-
-        String where;
-        if (label == null) {
-            where = "id NOT IN (SELECT message_id FROM Message_Label)";
-        } else {
-            where = "id IN (SELECT message_id FROM Message_Label WHERE label_id=" + label.getId() + ")";
-        }
-        List<UUID> result = new LinkedList<>();
-        SQLiteDatabase db = sql.getReadableDatabase();
-        try (Cursor c = db.query(
-            TABLE_NAME, projection,
-            where,
-            null, null, null, null
-        )) {
-            while (c.moveToNext()) {
-                byte[] uuidBytes = c.getBlob(c.getColumnIndex(COLUMN_CONVERSATION));
-                result.add(asUuid(uuidBytes));
-            }
-        }
-        return result;
-    }
-
-
-    private void updateParents(SQLiteDatabase db, Plaintext message) {
-        if (message.getInventoryVector() == null || message.getParents().isEmpty()) {
-            // There are no parents to save yet (they are saved in the extended data, that's enough for now)
-            return;
-        }
-        byte[] childIV = message.getInventoryVector().getHash();
-        db.delete(PARENTS_TABLE_NAME, "child=?", new String[]{hex(childIV)});
-
-        // save new parents
-        int order = 0;
-        for (InventoryVector parentIV : message.getParents()) {
-            Plaintext parent = getMessage(parentIV);
-            if (parent != null) {
-                mergeConversations(db, parent.getConversationId(), message.getConversationId());
-                order++;
-                ContentValues values = new ContentValues();
-                values.put("parent", parentIV.getHash());
-                values.put("child", childIV);
-                values.put("pos", order);
-                values.put("conversation", UuidUtils.asBytes(message.getConversationId()));
-                db.insertOrThrow(PARENTS_TABLE_NAME, null, values);
-            }
-        }
-    }
-
-    /**
-     * Replaces every occurrence of the source conversation ID with the target ID
-     *
-     * @param db     is used to keep everything within one transaction
-     * @param source ID of the conversation to be merged
-     * @param target ID of the merge target
-     */
-    private void mergeConversations(SQLiteDatabase db, UUID source, UUID target) {
-        ContentValues values = new ContentValues();
-        values.put("conversation", UuidUtils.asBytes(target));
-        String[] whereArgs = {hex(UuidUtils.asBytes(source))};
-        db.update(TABLE_NAME, values, "conversation=?", whereArgs);
-        db.update(PARENTS_TABLE_NAME, values, "conversation=?", whereArgs);
-    }
-
-    @NonNull
-    private List<Long> findIds(String where) {
-        List<Long> result = new LinkedList<>();
-
-        // Define a projection that specifies which columns from the database
-        // you will actually use after this query.
-        String[] projection = {
-            COLUMN_ID
-        };
-
-        SQLiteDatabase db = sql.getReadableDatabase();
-        try (Cursor c = db.query(
-            TABLE_NAME, projection,
-            where,
-            null, null, null,
-            COLUMN_RECEIVED + " DESC, " + COLUMN_SENT + " DESC"
-        )) {
-            while (c.moveToNext()) {
-                long id = c.getLong(0);
-                result.add(id);
-            }
-        }
-        return result;
-    }
-
-    @NonNull
-    protected List<Plaintext> find(String where) {
-        List<Plaintext> result = new LinkedList<>();
-
-        // Define a projection that specifies which columns from the database
-        // you will actually use after this query.
-        String[] projection = {
-            COLUMN_ID,
-            COLUMN_IV,
-            COLUMN_TYPE,
-            COLUMN_SENDER,
-            COLUMN_RECIPIENT,
-            COLUMN_DATA,
-            COLUMN_ACK_DATA,
-            COLUMN_SENT,
-            COLUMN_RECEIVED,
-            COLUMN_STATUS,
-            COLUMN_TTL,
-            COLUMN_RETRIES,
-            COLUMN_NEXT_TRY,
-            COLUMN_CONVERSATION
-        };
-
-        SQLiteDatabase db = sql.getReadableDatabase();
-        try (Cursor c = db.query(
-            TABLE_NAME, projection,
-            where,
-            null, null, null,
-            COLUMN_RECEIVED + " DESC, " + COLUMN_SENT + " DESC"
-        )) {
-            while (c.moveToNext()) {
-                byte[] iv = c.getBlob(c.getColumnIndex(COLUMN_IV));
-                byte[] data = c.getBlob(c.getColumnIndex(COLUMN_DATA));
-                Plaintext.Type type = Plaintext.Type.valueOf(c.getString(c.getColumnIndex
-                    (COLUMN_TYPE)));
-                Plaintext.Builder builder = Plaintext.readWithoutSignature(type,
-                    new ByteArrayInputStream(data));
-                long id = c.getLong(c.getColumnIndex(COLUMN_ID));
-                builder.id(id);
-                builder.IV(InventoryVector.fromHash(iv));
-                String sender = c.getString(c.getColumnIndex(COLUMN_SENDER));
-                if (sender != null) {
-                    BitmessageAddress address = ctx.getAddressRepository().getAddress(sender);
-                    if (address != null) {
-                        builder.from(address);
-                    } else {
-                        builder.from(new BitmessageAddress(sender));
-                    }
-                }
-                String recipient = c.getString(c.getColumnIndex(COLUMN_RECIPIENT));
-                if (recipient != null) {
-                    BitmessageAddress address = ctx.getAddressRepository().getAddress(recipient);
-                    if (address != null) {
-                        builder.to(address);
-                    } else {
-                        builder.to(new BitmessageAddress(sender));
-                    }
-                }
-                builder.ackData(c.getBlob(c.getColumnIndex(COLUMN_ACK_DATA)));
-                builder.sent(c.getLong(c.getColumnIndex(COLUMN_SENT)));
-                builder.received(c.getLong(c.getColumnIndex(COLUMN_RECEIVED)));
-                builder.status(Plaintext.Status.valueOf(c.getString(c.getColumnIndex
-                    (COLUMN_STATUS))));
-                builder.ttl(c.getLong(c.getColumnIndex(COLUMN_TTL)));
-                builder.retries(c.getInt(c.getColumnIndex(COLUMN_RETRIES)));
-                int nextTryColumn = c.getColumnIndex(COLUMN_NEXT_TRY);
-                if (!c.isNull(nextTryColumn)) {
-                    builder.nextTry(c.getLong(nextTryColumn));
-                }
-                builder.conversation(asUuid(c.getBlob(c.getColumnIndex(COLUMN_CONVERSATION))));
-                builder.labels(findLabels(id));
-                result.add(builder.build());
-            }
-        }
-        return result;
-    }
-
-    private Collection<Label> findLabels(long id) {
-        return findLabels("id IN (SELECT label_id FROM Message_Label WHERE message_id=" + id + ")");
-    }
-
-    @Override
-    public void save(Plaintext message) {
-        saveContactIfNecessary(message.getFrom());
-        saveContactIfNecessary(message.getTo());
-        SQLiteDatabase db = sql.getWritableDatabase();
-        try {
-            db.beginTransaction();
-
-            // save message
-            if (message.getId() == null) {
-                insert(db, message);
-            } else {
-                update(db, message);
-            }
-
-            updateParents(db, message);
-
-            // remove existing labels
-            db.delete(JOIN_TABLE_NAME, "message_id=?", new String[]{valueOf(message.getId())});
-
-            // save labels
-            ContentValues values = new ContentValues();
-            for (Label label : message.getLabels()) {
-                values.put(JT_COLUMN_LABEL, (Long) label.getId());
-                values.put(JT_COLUMN_MESSAGE, (Long) message.getId());
-                db.insertOrThrow(JOIN_TABLE_NAME, null, values);
-            }
-            db.setTransactionSuccessful();
-        } catch (SQLiteConstraintException e) {
-            LOG.trace(e.getMessage(), e);
-        } finally {
-            db.endTransaction();
-        }
-    }
-
-    private ContentValues getValues(Plaintext message) {
-        ContentValues values = new ContentValues();
-        values.put(COLUMN_IV, message.getInventoryVector() == null ? null : message
-            .getInventoryVector().getHash());
-        values.put(COLUMN_TYPE, message.getType().name());
-        values.put(COLUMN_SENDER, message.getFrom().getAddress());
-        values.put(COLUMN_RECIPIENT, message.getTo() == null ? null : message.getTo().getAddress());
-        values.put(COLUMN_DATA, Encode.bytes(message));
-        values.put(COLUMN_ACK_DATA, message.getAckData());
-        values.put(COLUMN_SENT, message.getSent());
-        values.put(COLUMN_RECEIVED, message.getReceived());
-        values.put(COLUMN_STATUS, message.getStatus().name());
-        values.put(COLUMN_INITIAL_HASH, message.getInitialHash());
-        values.put(COLUMN_TTL, message.getTTL());
-        values.put(COLUMN_RETRIES, message.getRetries());
-        values.put(COLUMN_NEXT_TRY, message.getNextTry());
-        values.put(COLUMN_CONVERSATION, UuidUtils.asBytes(message.getConversationId()));
-        return values;
-    }
-
-    private void insert(SQLiteDatabase db, Plaintext message) {
-        long id = db.insertOrThrow(TABLE_NAME, null, getValues(message));
-        message.setId(id);
-    }
-
-    private void update(SQLiteDatabase db, Plaintext message) {
-        db.update(TABLE_NAME, getValues(message), "id=?", new String[]{valueOf(message.getId())});
-    }
-
-    @Override
-    public void remove(Plaintext message) {
-        SQLiteDatabase db = sql.getWritableDatabase();
-        db.delete(TABLE_NAME, "id = " + message.getId(), null);
-    }
-}

app/src/main/java/ch/dissem/apps/abit/repository/AndroidMessageRepository.kt

@@ -0,0 +1,403 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.apps.abit.repository
+
+import android.content.ContentValues
+import android.content.Context
+import android.database.Cursor
+import android.database.DatabaseUtils
+import android.database.sqlite.SQLiteConstraintException
+import android.database.sqlite.SQLiteDatabase
+import ch.dissem.apps.abit.util.Labels
+import ch.dissem.apps.abit.util.UuidUtils
+import ch.dissem.apps.abit.util.UuidUtils.asUuid
+import ch.dissem.bitmessage.entity.BitmessageAddress
+import ch.dissem.bitmessage.entity.Plaintext
+import ch.dissem.bitmessage.entity.valueobject.InventoryVector
+import ch.dissem.bitmessage.entity.valueobject.Label
+import ch.dissem.bitmessage.ports.AbstractMessageRepository
+import ch.dissem.bitmessage.ports.MessageRepository
+import ch.dissem.bitmessage.utils.Encode
+import ch.dissem.bitmessage.utils.Strings.hex
+import org.slf4j.LoggerFactory
+import java.io.ByteArrayInputStream
+import java.util.*
+
+/**
+ * [MessageRepository] implementation using the Android SQL API.
+ */
+class AndroidMessageRepository(private val sql: SqlHelper, private val context: Context) : AbstractMessageRepository() {
+
+    override fun findMessages(label: Label?): List<Plaintext> {
+        if (label === LABEL_ARCHIVE) {
+            return super.findMessages(null as Label?)
+        } else {
+            return super.findMessages(label)
+        }
+    }
+
+    fun findMessageIds(label: Label): List<Long> {
+        if (label === LABEL_ARCHIVE) {
+            return findIds("id NOT IN (SELECT message_id FROM Message_Label)")
+        } else {
+            return findIds("id IN (SELECT message_id FROM Message_Label WHERE label_id=" + label.id + ")")
+        }
+    }
+
+    public override fun findLabels(where: String): List<Label> {
+        val result = LinkedList<Label>()
+
+        // Define a projection that specifies which columns from the database
+        // you will actually use after this query.
+        val projection = arrayOf(LBL_COLUMN_ID, LBL_COLUMN_LABEL, LBL_COLUMN_TYPE, LBL_COLUMN_COLOR)
+
+        val db = sql.readableDatabase
+        db.query(
+                LBL_TABLE_NAME, projection,
+                where, null, null, null,
+                LBL_COLUMN_ORDER
+        ).use { c ->
+            while (c.moveToNext()) {
+                result.add(getLabel(c))
+            }
+        }
+        return result
+    }
+
+    private fun getLabel(c: Cursor): Label {
+        val typeName = c.getString(c.getColumnIndex(LBL_COLUMN_TYPE))
+        val type = if (typeName == null) null else Label.Type.valueOf(typeName)
+        val text: String? = Labels.getText(type, null, context)
+        val label = Label(
+                text ?: c.getString(c.getColumnIndex(LBL_COLUMN_LABEL)),
+                type,
+                c.getInt(c.getColumnIndex(LBL_COLUMN_COLOR)))
+        label.id = c.getLong(c.getColumnIndex(LBL_COLUMN_ID))
+        return label
+    }
+
+    override fun save(label: Label) {
+        val db = sql.writableDatabase
+        if (label.id != null) {
+            val values = ContentValues()
+            values.put(LBL_COLUMN_LABEL, label.toString())
+            values.put(LBL_COLUMN_TYPE, label.type?.name)
+            values.put(LBL_COLUMN_COLOR, label.color)
+            values.put(LBL_COLUMN_ORDER, label.ord)
+            db.update(LBL_TABLE_NAME, values, "id=?", arrayOf(label.id.toString()))
+        } else {
+            try {
+                db.beginTransaction()
+
+                val exists = DatabaseUtils.queryNumEntries(db, LBL_TABLE_NAME, "label=?", arrayOf(label.toString())) > 0
+
+                if (exists) {
+                    val values = ContentValues()
+                    values.put(LBL_COLUMN_TYPE, label.type?.name)
+                    values.put(LBL_COLUMN_COLOR, label.color)
+                    values.put(LBL_COLUMN_ORDER, label.ord)
+                    db.update(LBL_TABLE_NAME, values, "label=?", arrayOf(label.toString()))
+                } else {
+                    val values = ContentValues()
+                    values.put(LBL_COLUMN_LABEL, label.toString())
+                    values.put(LBL_COLUMN_TYPE, label.type?.name)
+                    values.put(LBL_COLUMN_COLOR, label.color)
+                    values.put(LBL_COLUMN_ORDER, label.ord)
+                    db.insertOrThrow(LBL_TABLE_NAME, null, values)
+                }
+                db.setTransactionSuccessful()
+            } finally {
+                db.endTransaction()
+            }
+        }
+    }
+
+    override fun countUnread(label: Label?): Int {
+        if (label === LABEL_ARCHIVE) {
+            return 0
+        } else if (label == null) {
+            return DatabaseUtils.queryNumEntries(
+                    sql.readableDatabase,
+                    TABLE_NAME,
+                    "id IN (SELECT message_id FROM Message_Label WHERE label_id IN (SELECT id FROM Label WHERE type=?))",
+                    arrayOf(Label.Type.UNREAD.name)
+            ).toInt()
+        } else {
+            return DatabaseUtils.queryNumEntries(
+                    sql.readableDatabase,
+                    TABLE_NAME,
+                    "        id IN (SELECT message_id FROM Message_Label WHERE label_id=?) " + "AND id IN (SELECT message_id FROM Message_Label WHERE label_id IN (SELECT id FROM Label WHERE type=?))",
+                    arrayOf(label.id.toString(), Label.Type.UNREAD.name)
+            ).toInt()
+        }
+    }
+
+    override fun findConversations(label: Label?): List<UUID> {
+        val projection = arrayOf(COLUMN_CONVERSATION)
+
+        val where: String
+        if (label == null) {
+            where = "id NOT IN (SELECT message_id FROM Message_Label)"
+        } else {
+            where = "id IN (SELECT message_id FROM Message_Label WHERE label_id=" + label.id + ")"
+        }
+        val result = LinkedList<UUID>()
+        val db = sql.readableDatabase
+        db.query(
+                TABLE_NAME, projection,
+                where, null, null, null, null
+        ).use { c ->
+            while (c.moveToNext()) {
+                val uuidBytes = c.getBlob(c.getColumnIndex(COLUMN_CONVERSATION))
+                result.add(asUuid(uuidBytes))
+            }
+        }
+        return result
+    }
+
+
+    private fun updateParents(db: SQLiteDatabase, message: Plaintext) {
+        if (message.inventoryVector == null || message.parents.isEmpty()) {
+            // There are no parents to save yet (they are saved in the extended data, that's enough for now)
+            return
+        }
+        val childIV = message.inventoryVector!!.hash
+        db.delete(PARENTS_TABLE_NAME, "child=?", arrayOf(hex(childIV)))
+
+        // save new parents
+        var order = 0
+        for (parentIV in message.parents) {
+            val parent = getMessage(parentIV)
+            if (parent != null) {
+                mergeConversations(db, parent.conversationId, message.conversationId)
+                order++
+                val values = ContentValues()
+                values.put("parent", parentIV.hash)
+                values.put("child", childIV)
+                values.put("pos", order)
+                values.put("conversation", UuidUtils.asBytes(message.conversationId))
+                db.insertOrThrow(PARENTS_TABLE_NAME, null, values)
+            }
+        }
+    }
+
+    /**
+     * Replaces every occurrence of the source conversation ID with the target ID
+
+     * @param db     is used to keep everything within one transaction
+     * *
+     * @param source ID of the conversation to be merged
+     * *
+     * @param target ID of the merge target
+     */
+    private fun mergeConversations(db: SQLiteDatabase, source: UUID, target: UUID) {
+        val values = ContentValues()
+        values.put("conversation", UuidUtils.asBytes(target))
+        val whereArgs = arrayOf(hex(UuidUtils.asBytes(source)))
+        db.update(TABLE_NAME, values, "conversation=?", whereArgs)
+        db.update(PARENTS_TABLE_NAME, values, "conversation=?", whereArgs)
+    }
+
+    private fun findIds(where: String): List<Long> {
+        val result = LinkedList<Long>()
+
+        // Define a projection that specifies which columns from the database
+        // you will actually use after this query.
+        val projection = arrayOf(COLUMN_ID)
+
+        val db = sql.readableDatabase
+        db.query(
+                TABLE_NAME, projection,
+                where, null, null, null,
+                "$COLUMN_RECEIVED DESC, $COLUMN_SENT DESC"
+        ).use { c ->
+            while (c.moveToNext()) {
+                val id = c.getLong(0)
+                result.add(id)
+            }
+        }
+        return result
+    }
+
+    override fun find(where: String): List<Plaintext> {
+        val result = LinkedList<Plaintext>()
+
+        // Define a projection that specifies which columns from the database
+        // you will actually use after this query.
+        val projection = arrayOf(COLUMN_ID, COLUMN_IV, COLUMN_TYPE, COLUMN_SENDER, COLUMN_RECIPIENT, COLUMN_DATA, COLUMN_ACK_DATA, COLUMN_SENT, COLUMN_RECEIVED, COLUMN_STATUS, COLUMN_TTL, COLUMN_RETRIES, COLUMN_NEXT_TRY, COLUMN_CONVERSATION)
+
+        val db = sql.readableDatabase
+        db.query(
+                TABLE_NAME, projection,
+                where, null, null, null,
+                "$COLUMN_RECEIVED DESC, $COLUMN_SENT DESC"
+        ).use { c ->
+            while (c.moveToNext()) {
+                val iv = c.getBlob(c.getColumnIndex(COLUMN_IV))
+                val data = c.getBlob(c.getColumnIndex(COLUMN_DATA))
+                val type = Plaintext.Type.valueOf(c.getString(c.getColumnIndex(COLUMN_TYPE)))
+                val builder = Plaintext.readWithoutSignature(type,
+                        ByteArrayInputStream(data))
+                val id = c.getLong(c.getColumnIndex(COLUMN_ID))
+                builder.id(id)
+                builder.IV(InventoryVector.fromHash(iv))
+                val sender = c.getString(c.getColumnIndex(COLUMN_SENDER))
+                if (sender != null) {
+                    val address = ctx.addressRepository.getAddress(sender)
+                    if (address != null) {
+                        builder.from(address)
+                    } else {
+                        builder.from(BitmessageAddress(sender))
+                    }
+                }
+                val recipient = c.getString(c.getColumnIndex(COLUMN_RECIPIENT))
+                if (recipient != null) {
+                    val address = ctx.addressRepository.getAddress(recipient)
+                    if (address != null) {
+                        builder.to(address)
+                    } else {
+                        builder.to(BitmessageAddress(sender))
+                    }
+                }
+                builder.ackData(c.getBlob(c.getColumnIndex(COLUMN_ACK_DATA)))
+                builder.sent(c.getLong(c.getColumnIndex(COLUMN_SENT)))
+                builder.received(c.getLong(c.getColumnIndex(COLUMN_RECEIVED)))
+                builder.status(Plaintext.Status.valueOf(c.getString(c.getColumnIndex(COLUMN_STATUS))))
+                builder.ttl(c.getLong(c.getColumnIndex(COLUMN_TTL)))
+                builder.retries(c.getInt(c.getColumnIndex(COLUMN_RETRIES)))
+                val nextTryColumn = c.getColumnIndex(COLUMN_NEXT_TRY)
+                if (!c.isNull(nextTryColumn)) {
+                    builder.nextTry(c.getLong(nextTryColumn))
+                }
+                builder.conversation(asUuid(c.getBlob(c.getColumnIndex(COLUMN_CONVERSATION))))
+                builder.labels(findLabels(id))
+                result.add(builder.build())
+            }
+        }
+        return result
+    }
+
+    private fun findLabels(id: Long) = findLabels("id IN (SELECT label_id FROM Message_Label WHERE message_id=$id)")
+
+    override fun save(message: Plaintext) {
+        saveContactIfNecessary(message.from)
+        saveContactIfNecessary(message.to)
+        val db = sql.writableDatabase
+        try {
+            db.beginTransaction()
+
+            // save message
+            if (message.id == null) {
+                insert(db, message)
+            } else {
+                update(db, message)
+            }
+
+            updateParents(db, message)
+
+            // remove existing labels
+            db.delete(JOIN_TABLE_NAME, "message_id=?", arrayOf(message.id.toString()))
+
+            // save labels
+            val values = ContentValues()
+            for (label in message.labels) {
+                values.put(JT_COLUMN_LABEL, label.id as Long?)
+                values.put(JT_COLUMN_MESSAGE, message.id as Long?)
+                db.insertOrThrow(JOIN_TABLE_NAME, null, values)
+            }
+            db.setTransactionSuccessful()
+        } catch (e: SQLiteConstraintException) {
+            LOG.trace(e.message, e)
+        } finally {
+            db.endTransaction()
+        }
+    }
+
+    private fun getValues(message: Plaintext): ContentValues {
+        val values = ContentValues()
+        values.put(COLUMN_IV, if (message.inventoryVector == null)
+            null
+        else
+            message
+                    .inventoryVector!!.hash)
+        values.put(COLUMN_TYPE, message.type.name)
+        values.put(COLUMN_SENDER, message.from.address)
+        values.put(COLUMN_RECIPIENT, if (message.to == null) null else message.to!!.address)
+        values.put(COLUMN_DATA, Encode.bytes(message))
+        values.put(COLUMN_ACK_DATA, message.ackData)
+        values.put(COLUMN_SENT, message.sent)
+        values.put(COLUMN_RECEIVED, message.received)
+        values.put(COLUMN_STATUS, message.status.name)
+        values.put(COLUMN_INITIAL_HASH, message.initialHash)
+        values.put(COLUMN_TTL, message.ttl)
+        values.put(COLUMN_RETRIES, message.retries)
+        values.put(COLUMN_NEXT_TRY, message.nextTry)
+        values.put(COLUMN_CONVERSATION, UuidUtils.asBytes(message.conversationId))
+        return values
+    }
+
+    private fun insert(db: SQLiteDatabase, message: Plaintext) {
+        val id = db.insertOrThrow(TABLE_NAME, null, getValues(message))
+        message.id = id
+    }
+
+    private fun update(db: SQLiteDatabase, message: Plaintext) {
+        db.update(TABLE_NAME, getValues(message), "id=?", arrayOf(message.id.toString()))
+    }
+
+    override fun remove(message: Plaintext) {
+        val db = sql.writableDatabase
+        db.delete(TABLE_NAME, "id = " + message.id!!, null)
+    }
+
+    companion object {
+        private val LOG = LoggerFactory.getLogger(AndroidMessageRepository::class.java)
+
+        @JvmField
+        val LABEL_ARCHIVE = Label("archive", null, 0)
+
+        private const val TABLE_NAME = "Message"
+        private const val COLUMN_ID = "id"
+        private const val COLUMN_IV = "iv"
+        private const val COLUMN_TYPE = "type"
+        private const val COLUMN_SENDER = "sender"
+        private const val COLUMN_RECIPIENT = "recipient"
+        private const val COLUMN_DATA = "data"
+        private const val COLUMN_ACK_DATA = "ack_data"
+        private const val COLUMN_SENT = "sent"
+        private const val COLUMN_RECEIVED = "received"
+        private const val COLUMN_STATUS = "status"
+        private const val COLUMN_TTL = "ttl"
+        private const val COLUMN_RETRIES = "retries"
+        private const val COLUMN_NEXT_TRY = "next_try"
+        private const val COLUMN_INITIAL_HASH = "initial_hash"
+        private const val COLUMN_CONVERSATION = "conversation"
+
+        private const val PARENTS_TABLE_NAME = "Message_Parent"
+
+        private const val JOIN_TABLE_NAME = "Message_Label"
+        private const val JT_COLUMN_MESSAGE = "message_id"
+        private const val JT_COLUMN_LABEL = "label_id"
+
+        private const val LBL_TABLE_NAME = "Label"
+        private const val LBL_COLUMN_ID = "id"
+        private const val LBL_COLUMN_LABEL = "label"
+        private const val LBL_COLUMN_TYPE = "type"
+        private const val LBL_COLUMN_COLOR = "color"
+        private const val LBL_COLUMN_ORDER = "ord"
+    }
+}

app/src/main/res/values/strings.xml

@@ -120,6 +120,8 @@ As an alternative you could configure a trusted node in the settings, but as of
     <string name="error_msg_recipient_missing">Please set a recipient</string>
     <string name="export_data">Export</string>
     <string name="export_data_summary">Export all messages and contacts (but not identities)</string>
+    <string name="import_data">Import</string>
+    <string name="import_data_summary">Import messages and contacts (but not identities)</string>
     <string name="request_acknowledgements">Request acknowledgements</string>
     <string name="request_acknowledgements_summary">Acknowledges allow making sure a message was received, but require additional time to send</string>
     <string name="got_it">Got it</string>

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

@@ -51,6 +51,11 @@
         android:title="@string/export_data"
         android:summary="@string/export_data_summary"
         />
+    <Preference
+        android:key="import"
+        android:title="@string/import_data"
+        android:summary="@string/import_data_summary"
+        />
     <Preference
         android:key="status"
         android:summary="@string/status_summary"