add support for apps to register alternative login methods

below the standard login a list of icons/button will be displayed

core/templates/login.php

@@ -41,5 +41,19 @@
 		<input type="submit" id="submit" class="login primary" value="<?php echo $l->t('Log in'); ?>"/>
 	</fieldset>
 </form>
-<?php OCP\Util::addscript('core', 'visitortimezone'); ?>
+<?php if (!empty($_['alt_login'])) { ?>
+<form>
+	<fieldset>
+		<legend style="margin-bottom: 20px;"><?php echo $l->t('Alternative Logins:') ?></legend>
+		<ul>
+			<? foreach($_['alt_login'] as $login): ?>
+				<li style="height: 40px;"><a class="button" href="<?php echo $login['href']; ?>" ><?php echo $login['name']; ?></a></li>
+				<?php endforeach; ?>
+		</ul>
+	</fieldset>
+</form>
+<?php } ?>
+
+<?php
+OCP\Util::addscript('core', 'visitortimezone');
 

lib/app.php

@@ -36,6 +36,7 @@ class OC_App{
 	static private $appTypes = array();
 	static private $loadedApps = array();
 	static private $checkedApps = array();
+	static private $altLogin = array();
 
 	/**
 	 * @brief loads all apps
@@ -557,6 +558,14 @@ class OC_App{
 		self::$personalForms[]= $app.'/'.$page.'.php';
 	}
 
+	public static function registerLogIn($entry) {
+		self::$altLogin[] = $entry;
+	}
+
+	public static function getAlternativeLogIns() {
+		return self::$altLogin;
+	}
+
 	/**
 	 * @brief: get a list of all apps in the apps folder
 	 * @return array or app names (string IDs)

lib/util.php

@@ -312,6 +312,8 @@ class OC_Util {
 			$redirect_url = OC_Util::sanitizeHTML($_REQUEST['redirect_url']);
 			$parameters['redirect_url'] = urlencode($redirect_url);
 		}
+
+		$parameters['alt_login'] = OC_App::getAlternativeLogIns();
 		OC_Template::printGuestPage("", "login", $parameters);
 	}