Call the logout API when we log out

Also try to refactor some of the login/logout code out of MatrixChat and into a separate Lifecycle.js. This still isn't great, but it at least gets some code out of MatrixClient.

src/Lifecycle.js

@@ -0,0 +1,98 @@
+/*
+Copyright 2015, 2016 OpenMarket Ltd
+
+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.
+*/
+
+import MatrixClientPeg from './MatrixClientPeg';
+import Notifier from './Notifier'
+import UserActivity from './UserActivity';
+import Presence from './Presence';
+import dis from './dispatcher';
+
+function login(credentials, options) {
+    credentials.guest = Boolean(credentials.guest);
+    console.log("onLoggedIn => %s (guest=%s)", credentials.userId, credentials.guest);
+    MatrixClientPeg.replaceUsingAccessToken(
+        credentials.homeserverUrl, credentials.identityServerUrl,
+        credentials.userId, credentials.accessToken, credentials.guest
+    );
+
+    dis.dispatch({action: 'on_logged_in'});
+
+    startMatrixClient(options);
+}
+
+function logout() {
+    if (MatrixClientPeg.get().isGuest()) {
+        // logout doesn't work for guest sessions
+        // Also we sometimes want to re-log in a guest session
+        // if we abort the login
+        _onLoggedOut();
+        return;
+    }
+
+    return MatrixClientPeg.get().logout().then(_onLoggedOut,
+        // Just throwing an error here is going to be very unhelpful
+        // if you're trying to log out because your server's down and
+        // you want to log into a different server, so just forget the
+        // access token. It's annoying that this will leave the access
+        // token still valid, but we should fix this by having access
+        // tokens expire (and if you really think you've been compromised,
+        // change your password).
+        _onLoggedOut
+    );
+}
+
+function startMatrixClient(options) {
+    // dispatch this before starting the matrix client: it's used
+    // to add listeners for the 'sync' event so otherwise we'd have
+    // a race condition (and we need to dispatch synchronously for this
+    // to work).
+    dis.dispatch({action: 'will_start_client'}, true);
+
+    Notifier.start();
+    UserActivity.start();
+    Presence.start();
+    MatrixClientPeg.get().startClient(MatrixClientPeg.opts);
+}
+
+function _onLoggedOut() {
+    if (window.localStorage) {
+        const hsUrl = window.localStorage.getItem("mx_hs_url");
+        const isUrl = window.localStorage.getItem("mx_is_url");
+        window.localStorage.clear();
+        // preserve our HS & IS URLs for convenience
+        // N.B. we cache them in hsUrl/isUrl and can't really inline them
+        // as getCurrentHsUrl() may call through to localStorage.
+        if (hsUrl) window.localStorage.setItem("mx_hs_url", hsUrl);
+        if (isUrl) window.localStorage.setItem("mx_is_url", isUrl);
+    }
+    _stopMatrixClient();
+
+    dis.dispatch({action: 'on_logged_out'});
+}
+
+// stop all the background processes related to the current client
+function _stopMatrixClient() {
+    Notifier.stop();
+    UserActivity.stop();
+    Presence.stop();
+    MatrixClientPeg.get().stopClient();
+    MatrixClientPeg.get().removeAllListeners();
+    MatrixClientPeg.unset();
+}
+
+module.exports = {
+    login, logout, startMatrixClient
+};