introduce pre-disable-app hook and use it for the encryption app to reset migration status if the app was disabled

apps/files_encryption/appinfo/app.php

@@ -22,6 +22,9 @@ if (!OC_Config::getValue('maintenance', false)) {
 	// Filesystem related hooks
 	OCA\Encryption\Helper::registerFilesystemHooks();
 
+	// App manager related hooks
+	OCA\Encryption\Helper::registerAppHooks();
+
 	stream_wrapper_register('crypt', 'OCA\Encryption\Stream');
 
 	// check if we are logged in

apps/files_encryption/hooks/hooks.php

@@ -543,4 +543,17 @@ class Hooks {
 
 		\OC_FileProxy::$enabled = $proxyStatus;
 	}
+
+	/**
+	 * set migration status back to '0' so that all new files get encrypted
+	 * if the app gets enabled again
+	 * @param array $params contains the app ID
+	 */
+	public static function preDisable($params) {
+		if ($params['app'] === 'files_encryption') {
+			$query = \OC_DB::prepare('UPDATE `*PREFIX*encryption` SET `migration_status`=0');
+			$query->execute();
+		}
+	}
+
 }

apps/files_encryption/lib/helper.php

@@ -62,6 +62,15 @@ class Helper {
 		\OCP\Util::connectHook('OC_Filesystem', 'post_rename', 'OCA\Encryption\Hooks', 'postRename');
 	}
 
+	/**
+	 * @brief register filesystem related hooks
+	 *
+	 */
+	public static function registerAppHooks() {
+
+		\OCP\Util::connectHook('OC_App', 'pre_disable', 'OCA\Encryption\Hooks', 'preDisable');
+	}
+
 	/**
 	 * @brief setup user for files_encryption
 	 *

lib/app.php

@@ -259,6 +259,7 @@ class OC_App{
 	 */
 	public static function disable( $app ) {
 		// check if app is a shipped app or not. if not delete
+		\OC_Hook::emit('OC_App', 'pre_disable', array('app' => $app));
 		OC_Appconfig::setValue( $app, 'enabled', 'no' );
 
 		// check if app is a shipped app or not. if not delete