First version of automatic contact discovery.

TODO:
- Configuration (much of it)
- Enabled by default?
- Which keys to import? Current state: All non-revoked and non-expired with matching userid
- Search for keys if already known? Current state: yes, may cause traffic (configuration: only when wifi?)
- Update interval: Currently Android handles it, might be good (causes automatic refresh on new contact and stuff like that) or bad (too many of refreshes)

OpenKeychain/src/main/AndroidManifest.xml

@@ -53,6 +53,10 @@
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.NFC" />
     <uses-permission android:name="android.permission.GET_ACCOUNTS" />
+    <uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS"/>
+    <uses-permission android:name="android.permission.MANAGE_ACCOUNTS"/>
+    <uses-permission android:name="android.permission.READ_SYNC_SETTINGS"/>
+    <uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS"/>
     <uses-permission android:name="android.permission.READ_CONTACTS" />
 
     <!-- android:allowBackup="false": Don't allow backup over adb backup or other apps! -->
@@ -435,6 +439,28 @@
             </intent-filter>
         </service>
 
+        <service android:name=".service.DummyAccountService">
+            <intent-filter>
+                <action android:name="android.accounts.AccountAuthenticator"/>
+            </intent-filter>
+            <meta-data
+                    android:name="android.accounts.AccountAuthenticator"
+                    android:resource="@xml/account_desc"/>
+        </service>
+
+        <service android:name=".service.ContactSyncAdapterService">
+            <intent-filter>
+                <action android:name="android.content.SyncAdapter"/>
+            </intent-filter>
+
+            <meta-data
+                    android:name="android.content.SyncAdapter"
+                    android:resource="@xml/sync_adapter_desc"/>
+            <meta-data
+                    android:name="android.provider.CONTACTS_STRUCTURE"
+                    android:resource="@xml/custom_pgp_contacts_structure"/>
+        </service>
+
     </application>
 
 </manifest>

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/KeychainApplication.java

@@ -17,6 +17,8 @@
 
 package org.sufficientlysecure.keychain;
 
+import android.accounts.Account;
+import android.accounts.AccountManager;
 import android.app.Application;
 import android.content.Context;
 import android.graphics.PorterDuff;
@@ -76,6 +78,17 @@ public class KeychainApplication extends Application {
 
         brandGlowEffect(getApplicationContext(),
                 getApplicationContext().getResources().getColor(R.color.emphasis));
+
+        setupAccountAsNeeded();
+    }
+
+    private void setupAccountAsNeeded() {
+        AccountManager manager = AccountManager.get(this);
+        Account[] accounts = manager.getAccountsByType(getPackageName());
+        if (accounts == null || accounts.length == 0) {
+            Account dummy = new Account(getString(R.string.app_name), getPackageName());
+            manager.addAccountExplicitly(dummy, null, null);
+        }
     }
 
     static void brandGlowEffect(Context context, int brandColor) {

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/helper/EmailKeyHelper.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.helper;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.Messenger;
+import org.sufficientlysecure.keychain.keyimport.HkpKeyserver;
+import org.sufficientlysecure.keychain.keyimport.ImportKeysListEntry;
+import org.sufficientlysecure.keychain.keyimport.Keyserver;
+import org.sufficientlysecure.keychain.service.KeychainIntentService;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class EmailKeyHelper {
+
+    public static void importContacts(Context context, Messenger messenger) {
+        importAll(context, messenger, ContactHelper.getContactMails(context));
+    }
+
+    public static void importAll(Context context, Messenger messenger, List<String> mails) {
+        Set<ImportKeysListEntry> keys = new HashSet<ImportKeysListEntry>();
+        for (String mail : mails) {
+            keys.addAll(getEmailKeys(context, mail));
+        }
+        importKeys(context, messenger, new ArrayList<ImportKeysListEntry>(keys));
+    }
+
+    public static List<ImportKeysListEntry> getEmailKeys(Context context, String mail) {
+        Set<ImportKeysListEntry> keys = new HashSet<ImportKeysListEntry>();
+
+        // Try _hkp._tcp SRV record first
+        String[] mailparts = mail.split("@");
+        if (mailparts.length == 2) {
+            HkpKeyserver hkp = HkpKeyserver.resolve(mailparts[1]);
+            if (hkp != null) {
+                keys.addAll(getEmailKeys(mail, hkp));
+            }
+        }
+
+        // Most users don't have the SRV record, so ask a default server as well
+        String[] servers = Preferences.getPreferences(context).getKeyServers();
+        if (servers != null && servers.length != 0) {
+            HkpKeyserver hkp = new HkpKeyserver(servers[0]);
+            keys.addAll(getEmailKeys(mail, hkp));
+        }
+        return new ArrayList<ImportKeysListEntry>(keys);
+    }
+
+    private static void importKeys(Context context, Messenger messenger, List<ImportKeysListEntry> keys) {
+        Intent importIntent = new Intent(context, KeychainIntentService.class);
+        importIntent.setAction(KeychainIntentService.ACTION_DOWNLOAD_AND_IMPORT_KEYS);
+        Bundle importData = new Bundle();
+        importData.putParcelableArrayList(KeychainIntentService.DOWNLOAD_KEY_LIST,
+                new ArrayList<ImportKeysListEntry>(keys));
+        importIntent.putExtra(KeychainIntentService.EXTRA_DATA, importData);
+        importIntent.putExtra(KeychainIntentService.EXTRA_MESSENGER, messenger);
+
+        context.startService(importIntent);
+    }
+
+    public static List<ImportKeysListEntry> getEmailKeys(String mail, Keyserver keyServer) {
+        Set<ImportKeysListEntry> keys = new HashSet<ImportKeysListEntry>();
+        try {
+            for (ImportKeysListEntry key : keyServer.search(mail)) {
+                if (key.isRevoked() || key.isExpired()) continue;
+                for (String userId : key.getUserIds()) {
+                    if (userId.toLowerCase().contains(mail.toLowerCase())) {
+                        keys.add(key);
+                    }
+                }
+            }
+        } catch (Keyserver.QueryFailedException ignored) {
+        } catch (Keyserver.QueryNeedsRepairException ignored) {
+        }
+        return new ArrayList<ImportKeysListEntry>(keys);
+    }
+}

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ContactSyncAdapterService.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.service;
+
+import android.accounts.Account;
+import android.app.Service;
+import android.content.AbstractThreadedSyncAdapter;
+import android.content.ContentProviderClient;
+import android.content.Intent;
+import android.content.SyncResult;
+import android.os.*;
+import org.sufficientlysecure.keychain.helper.EmailKeyHelper;
+import org.sufficientlysecure.keychain.util.Log;
+
+public class ContactSyncAdapterService extends Service {
+
+    private class ContactSyncAdapter extends AbstractThreadedSyncAdapter {
+
+        public ContactSyncAdapter() {
+            super(ContactSyncAdapterService.this, true);
+        }
+
+        @Override
+        public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider,
+                                  final SyncResult syncResult) {
+            EmailKeyHelper.importContacts(getContext(), new Messenger(new Handler(Looper.getMainLooper(),
+                    new Handler.Callback() {
+                        @Override
+                        public boolean handleMessage(Message msg) {
+                            Bundle data = msg.getData();
+                            switch (msg.arg1) {
+                                case KeychainIntentServiceHandler.MESSAGE_OKAY:
+                                    return true;
+                                case KeychainIntentServiceHandler.MESSAGE_UPDATE_PROGRESS:
+                                    if (data.containsKey(KeychainIntentServiceHandler.DATA_PROGRESS) &&
+                                            data.containsKey(KeychainIntentServiceHandler.DATA_PROGRESS_MAX)) {
+                                        Log.d("Keychain/ContactSync/DownloadKeys", "Progress: " +
+                                                data.getInt(KeychainIntentServiceHandler.DATA_PROGRESS) + "/" +
+                                                data.getInt(KeychainIntentServiceHandler.DATA_PROGRESS_MAX));
+                                        return false;
+                                    }
+                                default:
+                                    Log.d("Keychain/ContactSync/DownloadKeys", "Syncing... " + msg.toString());
+                                    return false;
+                            }
+                        }
+                    })));
+        }
+    }
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        return new ContactSyncAdapter().getSyncAdapterBinder();
+    }
+}

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/DummyAccountService.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.service;
+
+import android.accounts.AbstractAccountAuthenticator;
+import android.accounts.Account;
+import android.accounts.AccountAuthenticatorResponse;
+import android.accounts.NetworkErrorException;
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.IBinder;
+import android.os.Message;
+import android.widget.Toast;
+import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.util.Log;
+
+/**
+ * This service actually does nothing, it's sole task is to show a Toast if the use tries to create an account.
+ */
+public class DummyAccountService extends Service {
+
+    private class Toaster {
+        private static final String TOAST_MESSAGE = "toast_message";
+        private Context context;
+        private Handler handler = new Handler(new Handler.Callback() {
+            @Override
+            public boolean handleMessage(Message msg) {
+                Toast.makeText(context, msg.getData().getString(TOAST_MESSAGE), Toast.LENGTH_LONG).show();
+                return true;
+            }
+        });
+
+        private Toaster(Context context) {
+            this.context = context;
+        }
+
+        public void toast(int resourceId) {
+            toast(context.getString(resourceId));
+        }
+
+        public void toast(String message) {
+            Message msg = new Message();
+            Bundle bundle = new Bundle();
+            bundle.putString(TOAST_MESSAGE, message);
+            msg.setData(bundle);
+            handler.sendMessage(msg);
+        }
+    }
+
+    private class Authenticator extends AbstractAccountAuthenticator {
+
+        public Authenticator() {
+            super(DummyAccountService.this);
+        }
+
+        @Override
+        public Bundle editProperties(AccountAuthenticatorResponse response, String accountType) {
+            Log.d("DummyAccountService", "editProperties");
+            return null;
+        }
+
+        @Override
+        public Bundle addAccount(AccountAuthenticatorResponse response, String accountType, String authTokenType,
+                                 String[] requiredFeatures, Bundle options) throws NetworkErrorException {
+            response.onResult(new Bundle());
+            toaster.toast(R.string.info_no_manual_account_creation);
+            Log.d("DummyAccountService", "addAccount");
+            return null;
+        }
+
+        @Override
+        public Bundle confirmCredentials(AccountAuthenticatorResponse response, Account account, Bundle options)
+                throws NetworkErrorException {
+            Log.d("DummyAccountService", "confirmCredentials");
+            return null;
+        }
+
+        @Override
+        public Bundle getAuthToken(AccountAuthenticatorResponse response, Account account, String authTokenType,
+                                   Bundle options) throws NetworkErrorException {
+            Log.d("DummyAccountService", "getAuthToken");
+            return null;
+        }
+
+        @Override
+        public String getAuthTokenLabel(String authTokenType) {
+            Log.d("DummyAccountService", "getAuthTokenLabel");
+            return null;
+        }
+
+        @Override
+        public Bundle updateCredentials(AccountAuthenticatorResponse response, Account account, String authTokenType,
+                                        Bundle options) throws NetworkErrorException {
+            Log.d("DummyAccountService", "updateCredentials");
+            return null;
+        }
+
+        @Override
+        public Bundle hasFeatures(AccountAuthenticatorResponse response, Account account, String[] features)
+                throws NetworkErrorException {
+            Log.d("DummyAccountService", "hasFeatures");
+            return null;
+        }
+    }
+
+    private Toaster toaster;
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        toaster = new Toaster(this);
+        return new Authenticator().getIBinder();
+    }
+}

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

@@ -518,5 +518,7 @@
     <string name="unknown_algorithm">unknown</string>
     <string name="can_sign_not">cannot sign</string>
     <string name="error_no_encrypt_subkey">No encryption subkey available!</string>
+    <string name="info_no_manual_account_creation">Do not create OpenKeychain-Accounts manually.
+        For more information, see Help.</string>
 
 </resources>

OpenKeychain/src/main/res/xml/account_desc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
+                       android:accountType="org.sufficientlysecure.keychain"
+                       android:icon="@drawable/icon"
+                       android:label="@string/app_name"/>

OpenKeychain/src/main/res/xml/custom_pgp_contacts_structure.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ContactsSource xmlns:android="http://schemas.android.com/apk/res/android">
+    <ContactsDataKind android:mimeType="vnd.android.cursor.item/vnd.org.sufficientlysecure.keychain.key"
+                      android:icon="@drawable/key_small"
+                      android:summaryColumn="data1"
+                      android:detailColumn="data2"/>
+</ContactsSource>

OpenKeychain/src/main/res/xml/sync_adapter_desc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
+              android:contentAuthority="com.android.contacts"
+              android:accountType="org.sufficientlysecure.keychain"
+              android:supportsUploading="false"
+              android:userVisible="true"/>