new filter hooks on favourite actions #2620

before a favourite action is made, fire a filter hook so plugins can
modify or cancel that action before it takes place.

src/socket.io/posts.js

@@ -168,6 +168,25 @@ function favouriteCommand(socket, command, eventName, notification, data, callba
 			return callback(new Error('[[error:post-deleted]]'));
 		}
 
+		/*
+		hooks:
+			filter.post.upvote
+			filter.post.downvote
+			filter.post.unvote
+			filter.post.favourite
+			filter.post.unfavourite
+		 */
+		plugins.fireHook('filter:post.' + command, data, function(err, filteredData) {
+			if (err) {
+				return callback(err);
+			}
+
+			executeFavouriteCommand(socket, command, eventName, notification, filteredData, callback);
+		});
+	});
+}
+
+function executeFavouriteCommand(socket, command, eventName, notification, data, callback) {
 	favourites[command](data.pid, socket.uid, function(err, result) {
 		if (err) {
 			return callback(err);
@@ -184,7 +203,6 @@ function favouriteCommand(socket, command, eventName, notification, data, callba
 		}
 		callback();
 	});
-	});
 }
 
 SocketPosts.sendNotificationToPostOwner = function(pid, fromuid, notification) {