First version of the import code that reads the new file format

src/com/fsck/k9/activity/Accounts.java

@@ -1,6 +1,8 @@
 
 package com.fsck.k9.activity;
 
+import java.io.FileNotFoundException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -22,6 +24,7 @@ import android.os.AsyncTask;
 import android.os.Bundle;
 import android.os.Handler;
 import android.util.Log;
+import android.util.SparseBooleanArray;
 import android.util.TypedValue;
 import android.view.ContextMenu;
 import android.view.Menu;
@@ -34,14 +37,17 @@ import android.view.View.OnClickListener;
 import android.webkit.WebView;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
+import android.widget.CheckedTextView;
 import android.widget.ImageButton;
 import android.widget.LinearLayout;
+import android.widget.ListAdapter;
 import android.widget.ListView;
 import android.widget.RelativeLayout;
 import android.widget.TextView;
 import android.widget.Toast;
 import android.widget.AdapterView.AdapterContextMenuInfo;
 import android.widget.AdapterView.OnItemClickListener;
+import android.widget.AdapterView.OnItemSelectedListener;
 
 import com.fsck.k9.Account;
 import com.fsck.k9.AccountStats;
@@ -64,6 +70,9 @@ import com.fsck.k9.mail.store.StorageManager;
 import com.fsck.k9.view.ColorChip;
 import com.fsck.k9.preferences.StorageExporter;
 import com.fsck.k9.preferences.StorageImportExportException;
+import com.fsck.k9.preferences.StorageImporter;
+import com.fsck.k9.preferences.StorageImporter.AccountDescription;
+import com.fsck.k9.preferences.StorageImporter.ImportContents;
 
 
 public class Accounts extends K9ListActivity implements OnItemClickListener, OnClickListener {
@@ -854,53 +863,13 @@ public class Accounts extends K9ListActivity implements OnItemClickListener, OnC
     }
 
     private void onImport(Uri uri) {
-        Toast.makeText(this, "Import is disabled for now", Toast.LENGTH_SHORT).show();
-        /*
-        Log.i(K9.LOG_TAG, "onImport importing from URI " + uri.getPath());
+        //Toast.makeText(this, "Import is disabled for now", Toast.LENGTH_SHORT).show();
 
-        final String fileName = uri.getPath();
-        AsyncUIProcessor.getInstance(Accounts.this.getApplication()).importSettings(this, uri, new ImportListener() {
-            @Override
-            public void success(int numAccounts) {
-                mHandler.progress(false);
-                String accountQtyText = getResources().getQuantityString(R.plurals.settings_import_success, numAccounts, numAccounts);
-                String messageText = getString(R.string.settings_import_success, accountQtyText, fileName);
-                showDialog(Accounts.this, R.string.settings_import_success_header, messageText);
-                runOnUiThread(new Runnable() {
-                    @Override
-                    public void run() {
-                        refresh();
-                    }
-                });
-            }
+        Log.i(K9.LOG_TAG, "onImport importing from URI " + uri.toString());
 
-            @Override
-            public void failure(String message, Exception e) {
-                mHandler.progress(false);
-                showDialog(Accounts.this, R.string.settings_import_failed_header, Accounts.this.getString(R.string.settings_import_failure, fileName, e.getLocalizedMessage()));
-            }
-
-            @Override
-            public void canceled() {
-                mHandler.progress(false);
-            }
-
-            @Override
-            public void started() {
-                runOnUiThread(new Runnable() {
-                    @Override
-                    public void run() {
-                        mHandler.progress(true);
-                        String toastText = Accounts.this.getString(R.string.settings_importing);
-                        Toast toast = Toast.makeText(Accounts.this, toastText, Toast.LENGTH_SHORT);
-                        toast.show();
-                    }
-                });
-
-            }
-        });
-        */
+        new ListImportContentsAsyncTask(uri, null).execute();
     }
+
     private void showDialog(final Context context, final int headerRes, final String message) {
         this.runOnUiThread(new Runnable() {
             @Override
@@ -1180,7 +1149,6 @@ public class Accounts extends K9ListActivity implements OnItemClickListener, OnC
 
         @Override
         protected void onPostExecute(Boolean success) {
-            setProgress(false);
             if (success) {
                 showDialog(Accounts.this, R.string.settings_export_success_header,
                         Accounts.this.getString(R.string.settings_export_success, mFileName));
@@ -1191,4 +1159,166 @@ public class Accounts extends K9ListActivity implements OnItemClickListener, OnC
             }
         }
     }
+
+    private class ImportAsyncTask extends AsyncTask<Void, Void, Boolean> {
+        private boolean mIncludeGlobals;
+        private Set<String> mAccountUuids;
+        private boolean mOverwrite;
+        private String mEncryptionKey;
+        private InputStream mInputStream;
+
+        private ImportAsyncTask(boolean includeGlobals, Set<String> accountUuids,
+                boolean overwrite, String encryptionKey, InputStream is) {
+            mIncludeGlobals = includeGlobals;
+            mAccountUuids = accountUuids;
+            mOverwrite = overwrite;
+            mEncryptionKey = encryptionKey;
+            mInputStream = is;
+        }
+
+        @Override
+        protected void onPreExecute() {
+            //TODO: show progress bar instead of displaying toast
+            String toastText = Accounts.this.getString(R.string.settings_importing);
+            Toast toast = Toast.makeText(Accounts.this, toastText, Toast.LENGTH_SHORT);
+            toast.show();
+        }
+
+        @Override
+        protected Boolean doInBackground(Void... params) {
+            try {
+                StorageImporter.importSettings(Accounts.this, mInputStream, mEncryptionKey,
+                        mIncludeGlobals, mAccountUuids, mOverwrite);
+            } catch (StorageImportExportException e) {
+                Log.w(K9.LOG_TAG, "Exception during export", e);
+                return false;
+            }
+            return true;
+        }
+
+        @Override
+        protected void onPostExecute(Boolean success) {
+            if (success) {
+                showDialog(Accounts.this, R.string.settings_import_success_header,
+                        //FIXME: use correct number of imported accounts
+                        Accounts.this.getString(R.string.settings_import_success, 3, "unknown"));
+                refresh();
+            } else {
+                //TODO: make the importer return an error code; translate that error code to a localized string here
+                showDialog(Accounts.this, R.string.settings_import_failed_header,
+                        Accounts.this.getString(R.string.settings_import_failure, "unknown", "Something went wrong"));
+            }
+        }
+    }
+
+    ImportContents mImportContents;
+    private class ListImportContentsAsyncTask extends AsyncTask<Void, Void, Boolean> {
+        private Uri mUri;
+        private String mEncryptionKey;
+        private InputStream mInputStream;
+
+        private ListImportContentsAsyncTask(Uri uri, String encryptionKey) {
+            mUri = uri;
+            mEncryptionKey = encryptionKey;
+        }
+
+        @Override
+        protected void onPreExecute() {
+            //TODO: show progress bar
+        }
+
+        @Override
+        protected Boolean doInBackground(Void... params) {
+            try {
+
+                InputStream is = getContentResolver().openInputStream(mUri);
+                mImportContents = StorageImporter.getImportStreamContents(
+                        Accounts.this, is, mEncryptionKey);
+
+                // Open another InputStream in the background. This is used later by ImportAsyncTask
+                mInputStream = getContentResolver().openInputStream(mUri);
+
+            } catch (StorageImportExportException e) {
+                Log.w(K9.LOG_TAG, "Exception during export", e);
+                return false;
+            }
+            catch (FileNotFoundException e) {
+                Log.w(K9.LOG_TAG, "Couldn't read content from URI " + mUri);
+                return false;
+            }
+            return true;
+        }
+
+        @Override
+        protected void onPostExecute(Boolean success) {
+            if (success) {
+                final ListView importSelectionView = new ListView(Accounts.this);
+                List<String> contents = new ArrayList<String>();
+                if (mImportContents.globalSettings) {
+                    contents.add("Global settings");
+                }
+                for (AccountDescription account : mImportContents.accounts) {
+                    contents.add(account.name);
+                }
+                importSelectionView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
+                importSelectionView.setAdapter(new ArrayAdapter<String>(Accounts.this, android.R.layout.simple_list_item_checked, contents));
+                importSelectionView.setOnItemSelectedListener(new OnItemSelectedListener() {
+                    @Override
+                    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
+                        CheckedTextView ctv = (CheckedTextView)view;
+                        ctv.setChecked(!ctv.isChecked());
+                    }
+
+                    @Override
+                    public void onNothingSelected(AdapterView<?> arg0) {}
+                });
+
+                //TODO: listview header: "Please select the settings you wish to import"
+                //TODO: listview footer: "Select all" / "Select none" buttons?
+                //TODO: listview footer: "Overwrite existing accounts?" checkbox
+
+                final AlertDialog.Builder builder = new AlertDialog.Builder(Accounts.this);
+                builder.setTitle("Import selection");
+                builder.setView(importSelectionView);
+                builder.setInverseBackgroundForced(true);
+                builder.setPositiveButton(R.string.okay_action,
+                    new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            ListAdapter adapter = importSelectionView.getAdapter();
+                            int count = adapter.getCount();
+                            SparseBooleanArray pos = importSelectionView.getCheckedItemPositions();
+
+                            boolean includeGlobals = mImportContents.globalSettings ? pos.get(0) : false;
+                            Set<String> accountUuids = new HashSet<String>();
+                            for (int i = 1; i < count; i++) {
+                                if (pos.get(i)) {
+                                    accountUuids.add(mImportContents.accounts.get(i-1).uuid);
+                                }
+                            }
+
+                            boolean overwrite = false; //TODO: get value from dialog
+
+                            dialog.dismiss();
+                            new ImportAsyncTask(includeGlobals, accountUuids, overwrite, mEncryptionKey, mInputStream).execute();
+                        }
+                    });
+                builder.setNegativeButton(R.string.cancel_action,
+                        new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                dialog.dismiss();
+                                try {
+                                    mInputStream.close();
+                                } catch (Exception e) { /* Ignore */ }
+                            }
+                        });
+                builder.show();
+            } else {
+                //TODO: make the importer return an error code; translate that error code to a localized string here
+                showDialog(Accounts.this, R.string.settings_import_failed_header,
+                        Accounts.this.getString(R.string.settings_import_failure, "unknown", "Something went wrong"));
+            }
+        }
+    }
 }

src/com/fsck/k9/preferences/StorageImporter.java

@@ -1,190 +1,716 @@
 package com.fsck.k9.preferences;
 
-import java.io.BufferedReader;
+import java.io.IOException;
 import java.io.InputStream;
-import java.io.StringReader;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Stack;
+import java.util.Set;
 import java.util.UUID;
 
-import javax.xml.parsers.SAXParser;
-import javax.xml.parsers.SAXParserFactory;
-
-import org.xml.sax.Attributes;
-import org.xml.sax.InputSource;
-import org.xml.sax.SAXException;
-import org.xml.sax.XMLReader;
-import org.xml.sax.helpers.DefaultHandler;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+import org.xmlpull.v1.XmlPullParserFactory;
 
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.util.Log;
 
 import com.fsck.k9.Account;
+import com.fsck.k9.Identity;
 import com.fsck.k9.K9;
 import com.fsck.k9.Preferences;
 import com.fsck.k9.helper.DateFormatter;
+import com.fsck.k9.helper.Utility;
 
 public class StorageImporter {
 
-    public static void importPreferences(Context context, InputStream is, String encryptionKey,
-            boolean globalSettings, String[] importAccountUuids, boolean overwrite)
-    throws StorageImportExportException {
+    /**
+     * Class to list the contents of an import file/stream.
+     *
+     * @see StorageImporter#getImportStreamContents(Context,InputStream,String)
+     */
+    public static class ImportContents {
+        /**
+         * True, if the import file contains global settings.
+         */
+        public final boolean globalSettings;
+
+        /**
+         * The list of accounts found in the import file. Never {@code null}.
+         */
+        public final List<AccountDescription> accounts;
+
+        private ImportContents(boolean globalSettings, List<AccountDescription> accounts) {
+            this.globalSettings = globalSettings;
+            this.accounts = accounts;
+        }
+    }
+
+    /**
+     * Class to describe an account (name, UUID).
+     *
+     * @see ImportContents
+     */
+    public static class AccountDescription {
+        /**
+         * The name of the account.
+         */
+        public final String name;
+
+        /**
+         * The UUID of the account.
+         */
+        public final String uuid;
+
+        private AccountDescription(String name, String uuid) {
+            this.name = name;
+            this.uuid = uuid;
+        }
+    }
+
+    public static boolean isImportStreamEncrypted(Context context, InputStream inputStream) {
+        return false;
+    }
+
+    /**
+     * Parses an import {@link InputStream} and returns information on whether it contains global
+     * settings and/or account settings. For all account configurations found, the name of the
+     * account along with the account UUID is returned.
+     *
+     * @param context
+     * @param inputStream
+     * @param encryptionKey
+     * @return
+     * @throws StorageImportExportException
+     */
+    public static ImportContents getImportStreamContents(Context context, InputStream inputStream,
+            String encryptionKey) throws StorageImportExportException {
 
         try {
-            SAXParserFactory spf = SAXParserFactory.newInstance();
-            SAXParser sp = spf.newSAXParser();
-            XMLReader xr = sp.getXMLReader();
-            StorageImporterHandler handler = new StorageImporterHandler();
-            xr.setContentHandler(handler);
+            // Parse the import stream but don't save individual settings (overview=true)
+            Imported imported = parseSettings(inputStream, false, null, false, true);
 
-            xr.parse(new InputSource(is));
+            // If the stream contains global settings the "globalSettings" member will not be null
+            boolean globalSettings = (imported.globalSettings != null);
 
-            ImportElement dataset = handler.getRootElement();
-            String storageFormat = dataset.attributes.get("version");
-            Log.i(K9.LOG_TAG, "Got settings file version " + storageFormat);
+            final List<AccountDescription> accounts = new ArrayList<AccountDescription>();
+            // If the stream contains at least one account configuration the "accounts" member
+            // will not be null.
+            if (imported.accounts != null) {
+                for (ImportedAccount account : imported.accounts.values()) {
+                    accounts.add(new AccountDescription(account.name, account.uuid));
+                }
+            }
+
+            return new ImportContents(globalSettings, accounts);
+
+        } catch (StorageImportExportException e) {
+            throw e;
+        } catch (Exception e) {
+            throw new StorageImportExportException(e);
+        }
+    }
+
+    /**
+     * Reads an import {@link InputStream} and imports the global settings and/or account
+     * configurations specified by the arguments.
+     *
+     * @param context
+     * @param inputStream
+     * @param encryptionKey
+     * @param globalSettings
+     * @param accountUuids
+     * @param overwrite
+     * @throws StorageImportExportException
+     */
+    public static void importSettings(Context context, InputStream inputStream, String encryptionKey,
+            boolean globalSettings, Set<String> accountUuids, boolean overwrite)
+    throws StorageImportExportException {
+
+        try
+        {
+            Imported imported = parseSettings(inputStream, globalSettings, accountUuids, overwrite, false);
 
             Preferences preferences = Preferences.getPreferences(context);
             SharedPreferences storage = preferences.getPreferences();
             SharedPreferences.Editor editor = storage.edit();
 
-            String data = dataset.data.toString();
-            List<Integer> accountNumbers = Account.getExistingAccountNumbers(preferences);
-            Log.i(K9.LOG_TAG, "Existing accountNumbers = " + accountNumbers);
-            /**
-             *  We translate UUIDs in the import file into new UUIDs in the local instance for the following reasons:
-             *  1) Accidentally importing the same file twice cannot damage settings in an existing account.
-             *     (Say, an account that was imported two months ago and has since had significant settings changes.)
-             *  2) Importing a single file multiple times allows for creating multiple accounts from the same template.
-             *  3) Exporting an account and importing back into the same instance is a poor-man's account copy (until a real
-             *     copy function is created, if ever)
-             */
-            Map<String, String> uuidMapping = new HashMap<String, String>();
-            String accountUuids = preferences.getPreferences().getString("accountUuids", null);
-
-            StringReader sr = new StringReader(data);
-            BufferedReader br = new BufferedReader(sr);
-            String line = null;
-            int settingsImported = 0;
-            int numAccounts = 0;
-            K9Krypto krypto = new K9Krypto(encryptionKey, K9Krypto.MODE.DECRYPT);
-            do {
-                line = br.readLine();
-                if (line != null) {
-                    //Log.i(K9.LOG_TAG, "Got line " + line);
-                    String[] comps = line.split(":");
-                    if (comps.length > 1) {
-                        String keyEnc = comps[0];
-                        String valueEnc = comps[1];
-                        String key = krypto.decrypt(keyEnc);
-                        String value = krypto.decrypt(valueEnc);
-                        String[] keyParts = key.split("\\.");
-                        if (keyParts.length > 1) {
-                            String oldUuid = keyParts[0];
-                            String newUuid = uuidMapping.get(oldUuid);
-                            if (newUuid == null) {
-                                newUuid = UUID.randomUUID().toString();
-                                uuidMapping.put(oldUuid, newUuid);
-
-                                Log.i(K9.LOG_TAG, "Mapping oldUuid " + oldUuid + " to newUuid " + newUuid);
-                            }
-                            keyParts[0] = newUuid;
-                            if ("accountNumber".equals(keyParts[1])) {
-                                int accountNumber = Account.findNewAccountNumber(accountNumbers);
-                                accountNumbers.add(accountNumber);
-                                value = Integer.toString(accountNumber);
-                                accountUuids += (accountUuids.length() != 0 ? "," : "") + newUuid;
-                                numAccounts++;
-                            }
-                            StringBuilder builder = new StringBuilder();
-                            for (String part : keyParts) {
-                                if (builder.length() > 0) {
-                                    builder.append(".");
-                                }
-                                builder.append(part);
-                            }
-                            key = builder.toString();
-                        }
-                        //Log.i(K9.LOG_TAG, "Setting " + key + " = " + value);
-                        settingsImported++;
-                        editor.putString(key, value);
-                    }
+            if (globalSettings) {
+                if (imported.globalSettings != null) {
+                    importGlobalSettings(editor, imported.globalSettings);
+                } else {
+                    Log.w(K9.LOG_TAG, "Was asked to import global settings but none found.");
                 }
+            }
 
-            } while (line != null);
+            if (accountUuids != null && accountUuids.size() > 0) {
+                if (imported.accounts != null) {
+                    List<String> newUuids = new ArrayList<String>();
+                    for (String accountUuid : accountUuids) {
+                        if (imported.accounts.containsKey(accountUuid)) {
+                            String newUuid = importAccount(context, editor, imported.accounts.get(accountUuid), overwrite);
+                            if (newUuid != null) {
+                                newUuids.add(newUuid);
+                            }
+                        } else {
+                            Log.w(K9.LOG_TAG, "Was asked to import account with UUID " +
+                                    accountUuid + ". But this account wasn't found.");
+                        }
+                    }
+                    if (newUuids.size() > 0) {
+                        String oldAccountUuids = storage.getString("accountUuids", "");
+                        String appendUuids = Utility.combine(newUuids.toArray(new String[0]), ',');
+                        String prefix = "";
+                        if (oldAccountUuids.length() > 0) {
+                            prefix = oldAccountUuids + ",";
+                        }
+                        editor.putString("accountUuids", prefix + appendUuids);
+                    }
+                } else {
+                    Log.w(K9.LOG_TAG, "Was asked to import at least one account but none found.");
+                }
+            }
 
-            editor.putString("accountUuids", accountUuids);
-            Log.i(K9.LOG_TAG, "Imported " + settingsImported + " settings and " + numAccounts + " accounts");
+            if (!editor.commit()) {
+                throw new StorageImportExportException("Couldn't save imported settings");
+            }
 
-            editor.commit();
-            Preferences.getPreferences(context).refreshAccounts();
+            preferences.refreshAccounts();
             DateFormatter.clearChosenFormat();
-            K9.loadPrefs(Preferences.getPreferences(context));
+            K9.loadPrefs(preferences);
             K9.setServicesEnabled(context);
 
+        } catch (StorageImportExportException e) {
+            throw e;
         } catch (Exception e) {
-            throw new StorageImportExportException();
+            throw new StorageImportExportException(e);
         }
     }
 
+    private static void importGlobalSettings(SharedPreferences.Editor editor,
+            ImportedSettings settings) {
+        //TODO: input validation
 
-    public static class ImportElement {
-        String name;
-        Map<String, String> attributes = new HashMap<String, String>();
-        Map<String, ImportElement> subElements = new HashMap<String, ImportElement>();
-        StringBuilder data = new StringBuilder();
+        for (Map.Entry<String, String> setting : settings.settings.entrySet()) {
+            String key = setting.getKey();
+            String value = setting.getValue();
+            //FIXME: drop this key during input validation. then remove this check
+            if ("accountUuids".equals(key)) {
+                continue;
+            }
+            editor.putString(key, value);
+        }
     }
 
-    private static class StorageImporterHandler extends DefaultHandler {
-        private ImportElement rootElement = new ImportElement();
-        private Stack<ImportElement> mOpenTags = new Stack<ImportElement>();
+    private static String importAccount(Context context, SharedPreferences.Editor editor,
+            ImportedAccount account, boolean overwrite) {
 
-        public ImportElement getRootElement() {
-            return this.rootElement;
+        //TODO: input validation
+        //TODO: remove latestOldMessageSeenTime?
+
+        Preferences prefs = Preferences.getPreferences(context);
+        Account[] accounts = prefs.getAccounts();
+
+        String uuid = account.uuid;
+        Account existingAccount = prefs.getAccount(uuid);
+        if (!overwrite && existingAccount != null) {
+            // An account with this UUID already exists, but we're not allowed to overwrite it.
+            // So generate a new UUID.
+            uuid = UUID.randomUUID().toString();
         }
 
-        @Override
-        public void startDocument() throws SAXException {
-        }
-
-        @Override
-        public void endDocument() throws SAXException {
-            /* Do nothing */
-        }
-
-        @Override
-        public void startElement(String namespaceURI, String localName,
-                                 String qName, Attributes attributes) throws SAXException {
-            Log.i(K9.LOG_TAG, "Starting element " + localName);
-            ImportElement element = new ImportElement();
-            element.name = localName;
-            mOpenTags.push(element);
-            for (int i = 0; i < attributes.getLength(); i++) {
-                String key = attributes.getLocalName(i);
-                String value = attributes.getValue(i);
-                Log.i(K9.LOG_TAG, "Got attribute " + key + " = " + value);
-                element.attributes.put(key, value);
+        String accountName = account.name;
+        if (isAccountNameUsed(accountName, accounts)) {
+            // Account name is already in use. So generate a new one by appending " (x)", where x
+            // is the first number >= 1 that results in an unused account name.
+            for (int i = 1; i <= accounts.length; i++) {
+                accountName = account.name + " (" + i + ")";
+                if (!isAccountNameUsed(accountName, accounts)) {
+                    break;
+                }
             }
         }
 
-        @Override
-        public void endElement(String namespaceURI, String localName, String qName) {
-            Log.i(K9.LOG_TAG, "Ending element " + localName);
-            ImportElement element = mOpenTags.pop();
-            ImportElement superElement = mOpenTags.empty() ? null : mOpenTags.peek();
-            if (superElement != null) {
-                superElement.subElements.put(element.name, element);
-            } else {
-                rootElement = element;
+        String accountKeyPrefix = uuid + ".";
+        editor.putString(accountKeyPrefix + Account.ACCOUNT_DESCRIPTION_KEY, accountName);
+
+        // Write account settings
+        for (Map.Entry<String, String> setting : account.settings.settings.entrySet()) {
+            //FIXME: drop this key during input validation. then remove this check
+            if ("accountNumber".equals(setting.getKey())) {
+                continue;
+            }
+
+            String key = accountKeyPrefix + setting.getKey();
+            String value = setting.getValue();
+            editor.putString(key, value);
+        }
+
+        // If it's a new account generate and write a new "accountNumber"
+        if (existingAccount == null || !uuid.equals(account.uuid)) {
+            int newAccountNumber = Account.generateAccountNumber(prefs);
+            editor.putString(accountKeyPrefix + "accountNumber", Integer.toString(newAccountNumber));
+        }
+
+        if (account.identities != null) {
+            importIdentities(editor, uuid, account, overwrite, existingAccount);
+        }
+
+        // Write folder settings
+        if (account.folders != null) {
+            for (ImportedFolder folder : account.folders) {
+                String folderKeyPrefix = uuid + "." + folder.name + ".";
+                for (Map.Entry<String, String> setting : folder.settings.settings.entrySet()) {
+                    String key = folderKeyPrefix + setting.getKey();
+                    String value = setting.getValue();
+                    editor.putString(key, value);
+                }
             }
         }
 
-        @Override
-        public void characters(char ch[], int start, int length) {
-            String value = new String(ch, start, length);
-            mOpenTags.peek().data.append(value);
+        //TODO: sync folder settings with localstore?
+
+        return (overwrite && existingAccount != null) ? null : uuid;
+    }
+
+    private static void importIdentities(SharedPreferences.Editor editor, String uuid,
+            ImportedAccount account, boolean overwrite, Account existingAccount) {
+
+        String accountKeyPrefix = uuid + ".";
+
+        // Gather information about existing identities for this account (if any)
+        int nextIdentityIndex = 0;
+        final List<Identity> existingIdentities;
+        if (overwrite && existingAccount != null) {
+            existingIdentities = existingAccount.getIdentities();
+            nextIdentityIndex = existingIdentities.size();
+        } else {
+            existingIdentities = new ArrayList<Identity>();
         }
+
+        // Write identities
+        for (ImportedIdentity identity : account.identities) {
+            int writeIdentityIndex = nextIdentityIndex;
+            if (existingIdentities.size() > 0) {
+                int identityIndex = findIdentity(identity, existingIdentities);
+                if (overwrite && identityIndex != -1) {
+                    writeIdentityIndex = identityIndex;
+                }
+            }
+            if (writeIdentityIndex == nextIdentityIndex) {
+                nextIdentityIndex++;
+            }
+
+            String identityDescription = identity.description;
+            if (isIdentityDescriptionUsed(identityDescription, existingIdentities)) {
+                // Identity description is already in use. So generate a new one by appending
+                // " (x)", where x is the first number >= 1 that results in an unused identity
+                // description.
+                for (int i = 1; i <= existingIdentities.size(); i++) {
+                    identityDescription = identity.description + " (" + i + ")";
+                    if (!isIdentityDescriptionUsed(identityDescription, existingIdentities)) {
+                        break;
+                    }
+                }
+            }
+
+            editor.putString(accountKeyPrefix + Account.IDENTITY_NAME_KEY + "." +
+                    writeIdentityIndex, identity.name);
+            editor.putString(accountKeyPrefix + Account.IDENTITY_EMAIL_KEY + "." +
+                    writeIdentityIndex, identity.email);
+            editor.putString(accountKeyPrefix + Account.IDENTITY_DESCRIPTION_KEY + "." +
+                    writeIdentityIndex, identityDescription);
+
+            // Write identity settings
+            for (Map.Entry<String, String> setting : identity.settings.settings.entrySet()) {
+                String key = setting.getKey();
+                String value = setting.getValue();
+                editor.putString(accountKeyPrefix + key + "." + writeIdentityIndex, value);
+            }
+        }
+    }
+
+    private static boolean isAccountNameUsed(String name, Account[] accounts) {
+        for (Account account : accounts) {
+            if (account.getDescription().equals(name)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static boolean isIdentityDescriptionUsed(String description, List<Identity> identities) {
+        for (Identity identitiy : identities) {
+            if (identitiy.getDescription().equals(description)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static int findIdentity(ImportedIdentity identity,
+            List<Identity> identities) {
+        for (int i = 0; i < identities.size(); i++) {
+            Identity existingIdentity = identities.get(i);
+            if (existingIdentity.getName().equals(identity.name) &&
+                    existingIdentity.getEmail().equals(identity.email)) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private static Imported parseSettings(InputStream inputStream, boolean globalSettings,
+            Set<String> accountUuids, boolean overwrite, boolean overview)
+    throws StorageImportExportException {
+
+        if (!overview && accountUuids == null) {
+            throw new IllegalArgumentException("Argument 'accountUuids' must not be null.");
+        }
+
+        try {
+            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
+            //factory.setNamespaceAware(true);
+            XmlPullParser xpp = factory.newPullParser();
+
+            InputStreamReader reader = new InputStreamReader(inputStream);
+            xpp.setInput(reader);
+
+            Imported imported = null;
+            int eventType = xpp.getEventType();
+            while (eventType != XmlPullParser.END_DOCUMENT) {
+                if(eventType == XmlPullParser.START_TAG) {
+                    if (StorageExporter.ROOT_ELEMENT.equals(xpp.getName())) {
+                        imported = parseRoot(xpp, globalSettings, accountUuids, overview);
+                    } else {
+                        Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                    }
+                }
+                eventType = xpp.next();
+            }
+
+            if (imported == null || (overview && imported.globalSettings == null &&
+                    imported.accounts == null)) {
+                throw new StorageImportExportException("Invalid import data");
+            }
+
+            return imported;
+        } catch (Exception e) {
+            throw new StorageImportExportException(e);
+        } finally {
+            try {
+                inputStream.close();
+            } catch (Exception e) { /* Ignore */ }
+        }
+    }
+
+    private static void skipToEndTag(XmlPullParser xpp, String endTag)
+    throws XmlPullParserException, IOException {
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG && endTag.equals(xpp.getName()))) {
+            eventType = xpp.next();
+        }
+    }
+
+    private static String getText(XmlPullParser xpp)
+    throws XmlPullParserException, IOException {
+
+        int eventType = xpp.next();
+        if (eventType != XmlPullParser.TEXT) {
+            return null;
+        }
+        return xpp.getText();
+    }
+
+    private static Imported parseRoot(XmlPullParser xpp, boolean globalSettings,
+            Set<String> accountUuids, boolean overview)
+    throws XmlPullParserException, IOException {
+
+        Imported result = new Imported();
+
+        //TODO: check version attribute
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG &&
+                 StorageExporter.ROOT_ELEMENT.equals(xpp.getName()))) {
+
+            if(eventType == XmlPullParser.START_TAG) {
+                String element = xpp.getName();
+                if (StorageExporter.GLOBAL_ELEMENT.equals(element)) {
+                    if (overview || globalSettings) {
+                        if (result.globalSettings == null) {
+                            if (overview) {
+                                result.globalSettings = new ImportedSettings();
+                                skipToEndTag(xpp, StorageExporter.GLOBAL_ELEMENT);
+                            } else {
+                                result.globalSettings = parseSettings(xpp, StorageExporter.GLOBAL_ELEMENT);
+                            }
+                        } else {
+                            skipToEndTag(xpp, StorageExporter.GLOBAL_ELEMENT);
+                            Log.w(K9.LOG_TAG, "More than one global settings element. Only using the first one!");
+                        }
+                    } else {
+                        skipToEndTag(xpp, StorageExporter.GLOBAL_ELEMENT);
+                        Log.i(K9.LOG_TAG, "Skipping global settings");
+                    }
+                } else if (StorageExporter.ACCOUNTS_ELEMENT.equals(element)) {
+                    if (result.accounts == null) {
+                        result.accounts = parseAccounts(xpp, accountUuids, overview);
+                    } else {
+                        Log.w(K9.LOG_TAG, "More than one accounts element. Only using the first one!");
+                    }
+                } else {
+                    Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                }
+            }
+            eventType = xpp.next();
+        }
+
+        return result;
+    }
+
+    private static ImportedSettings parseSettings(XmlPullParser xpp, String endTag)
+    throws XmlPullParserException, IOException {
+
+        ImportedSettings result = null;
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG && endTag.equals(xpp.getName()))) {
+
+            if(eventType == XmlPullParser.START_TAG) {
+                String element = xpp.getName();
+                if (StorageExporter.VALUE_ELEMENT.equals(element)) {
+                    String key = xpp.getAttributeValue(null, StorageExporter.KEY_ATTRIBUTE);
+                    String value = getText(xpp);
+
+                    if (result == null) {
+                        result = new ImportedSettings();
+                    }
+
+                    if (result.settings.containsKey(key)) {
+                        Log.w(K9.LOG_TAG, "Already read key \"" + key + "\". Ignoring value \"" + value + "\"");
+                    } else {
+                        result.settings.put(key, value);
+                    }
+                } else {
+                    Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                }
+            }
+            eventType = xpp.next();
+        }
+
+        return result;
+    }
+
+    private static Map<String, ImportedAccount> parseAccounts(XmlPullParser xpp,
+            Set<String> accountUuids, boolean overview)
+    throws XmlPullParserException, IOException {
+
+        Map<String, ImportedAccount> accounts = null;
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG &&
+                 StorageExporter.ACCOUNTS_ELEMENT.equals(xpp.getName()))) {
+
+            if(eventType == XmlPullParser.START_TAG) {
+                String element = xpp.getName();
+                if (StorageExporter.ACCOUNT_ELEMENT.equals(element)) {
+                    if (accounts == null) {
+                        accounts = new HashMap<String, ImportedAccount>();
+                    }
+
+                    ImportedAccount account = parseAccount(xpp, accountUuids, overview);
+
+                    if (!accounts.containsKey(account.uuid)) {
+                        accounts.put(account.uuid, account);
+                    } else {
+                        Log.w(K9.LOG_TAG, "Duplicate account entries with UUID " + account.uuid +
+                                ". Ignoring!");
+                    }
+                } else {
+                    Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                }
+            }
+            eventType = xpp.next();
+        }
+
+        return accounts;
+    }
+
+    private static ImportedAccount parseAccount(XmlPullParser xpp, Set<String> accountUuids,
+            boolean overview)
+    throws XmlPullParserException, IOException {
+
+        ImportedAccount account = new ImportedAccount();
+
+        String uuid = xpp.getAttributeValue(null, StorageExporter.UUID_ATTRIBUTE);
+        account.uuid = uuid;
+
+        if (overview || accountUuids.contains(uuid)) {
+            int eventType = xpp.next();
+            while (!(eventType == XmlPullParser.END_TAG &&
+                     StorageExporter.ACCOUNT_ELEMENT.equals(xpp.getName()))) {
+
+                if(eventType == XmlPullParser.START_TAG) {
+                    String element = xpp.getName();
+                    if (StorageExporter.NAME_ELEMENT.equals(element)) {
+                        account.name = getText(xpp);
+                    } else if (StorageExporter.SETTINGS_ELEMENT.equals(element)) {
+                        if (overview) {
+                            skipToEndTag(xpp, StorageExporter.SETTINGS_ELEMENT);
+                        } else {
+                            account.settings = parseSettings(xpp, StorageExporter.SETTINGS_ELEMENT);
+                        }
+                    } else if (StorageExporter.IDENTITIES_ELEMENT.equals(element)) {
+                        if (overview) {
+                            skipToEndTag(xpp, StorageExporter.IDENTITIES_ELEMENT);
+                        } else {
+                            account.identities = parseIdentities(xpp);
+                        }
+                    } else if (StorageExporter.FOLDERS_ELEMENT.equals(element)) {
+                        if (overview) {
+                            skipToEndTag(xpp, StorageExporter.FOLDERS_ELEMENT);
+                        } else {
+                            account.folders = parseFolders(xpp);
+                        }
+                    } else {
+                        Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                    }
+                }
+                eventType = xpp.next();
+            }
+        } else {
+            skipToEndTag(xpp, StorageExporter.ACCOUNT_ELEMENT);
+            Log.i(K9.LOG_TAG, "Skipping account with UUID " + uuid);
+        }
+
+        return account;
+    }
+
+    private static List<ImportedIdentity> parseIdentities(XmlPullParser xpp)
+    throws XmlPullParserException, IOException {
+        List<ImportedIdentity> identities = null;
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG &&
+                 StorageExporter.IDENTITIES_ELEMENT.equals(xpp.getName()))) {
+
+            if(eventType == XmlPullParser.START_TAG) {
+                String element = xpp.getName();
+                if (StorageExporter.IDENTITY_ELEMENT.equals(element)) {
+                    if (identities == null) {
+                        identities = new ArrayList<ImportedIdentity>();
+                    }
+
+                    ImportedIdentity identity = parseIdentity(xpp);
+                    identities.add(identity);
+                } else {
+                    Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                }
+            }
+            eventType = xpp.next();
+        }
+
+        return identities;
+    }
+
+    private static ImportedIdentity parseIdentity(XmlPullParser xpp)
+    throws XmlPullParserException, IOException {
+        ImportedIdentity identity = new ImportedIdentity();
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG &&
+                 StorageExporter.IDENTITY_ELEMENT.equals(xpp.getName()))) {
+
+            if(eventType == XmlPullParser.START_TAG) {
+                String element = xpp.getName();
+                if (StorageExporter.NAME_ELEMENT.equals(element)) {
+                    identity.name = getText(xpp);
+                } else if (StorageExporter.EMAIL_ELEMENT.equals(element)) {
+                    identity.email = getText(xpp);
+                } else if (StorageExporter.DESCRIPTION_ELEMENT.equals(element)) {
+                    identity.description = getText(xpp);
+                } else if (StorageExporter.SETTINGS_ELEMENT.equals(element)) {
+                    identity.settings = parseSettings(xpp, StorageExporter.SETTINGS_ELEMENT);
+                } else {
+                    Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                }
+            }
+            eventType = xpp.next();
+        }
+
+        return identity;
+    }
+
+    private static List<ImportedFolder> parseFolders(XmlPullParser xpp)
+    throws XmlPullParserException, IOException {
+        List<ImportedFolder> folders = null;
+
+        int eventType = xpp.next();
+        while (!(eventType == XmlPullParser.END_TAG &&
+                 StorageExporter.FOLDERS_ELEMENT.equals(xpp.getName()))) {
+
+            if(eventType == XmlPullParser.START_TAG) {
+                String element = xpp.getName();
+                if (StorageExporter.FOLDER_ELEMENT.equals(element)) {
+                    if (folders == null) {
+                        folders = new ArrayList<ImportedFolder>();
+                    }
+
+                    ImportedFolder folder = parseFolder(xpp);
+                    folders.add(folder);
+                } else {
+                    Log.w(K9.LOG_TAG, "Unexpected start tag: " + xpp.getName());
+                }
+            }
+            eventType = xpp.next();
+        }
+
+        return folders;
+    }
+
+    private static ImportedFolder parseFolder(XmlPullParser xpp)
+    throws XmlPullParserException, IOException {
+        ImportedFolder folder = new ImportedFolder();
+
+        String name = xpp.getAttributeValue(null, StorageExporter.NAME_ATTRIBUTE);
+        folder.name = name;
+
+        folder.settings = parseSettings(xpp, StorageExporter.FOLDER_ELEMENT);
+
+        return folder;
+    }
+
+    private static class Imported {
+        public ImportedSettings globalSettings;
+        public Map<String, ImportedAccount> accounts;
+    }
+
+    private static class ImportedSettings {
+        public Map<String, String> settings = new HashMap<String, String>();
+    }
+
+    private static class ImportedAccount {
+        public String uuid;
+        public String name;
+        public ImportedSettings settings;
+        public List<ImportedIdentity> identities;
+        public List<ImportedFolder> folders;
+    }
+
+    private static class ImportedIdentity {
+        public String name;
+        public String email;
+        public String description;
+        public ImportedSettings settings;
+    }
+
+    private static class ImportedFolder {
+        public String name;
+        public ImportedSettings settings;
     }
 }