Persist announcements in the database

lib/database/update.js

@@ -0,0 +1,36 @@
+var db = require("../database");
+var Logger = require("../logger");
+
+const DB_VERSION = 1;
+
+module.exports.checkVersion = function () {
+    db.query("SELECT `key`,`value` FROM `meta` WHERE `key`=?", ["db_version"], function (err, rows) {
+        if (err) {
+            return;
+        }
+
+        if (rows.length === 0) {
+            Logger.errlog.log("[Warning] db_version key missing from database.  Setting " +
+                              "db_version=" + DB_VERSION);
+            db.query("INSERT INTO `meta` (`key`, `value`) VALUES ('db_version', ?)",
+                     [DB_VERSION],
+                     function (err) {
+            });
+        } else {
+            var v = parseInt(rows[0].value);
+            var next = function () {
+                if (v < DB_VERSION) {
+                    update(v++, next);
+                } else {
+                    db.query("UPDATE `meta` SET `value`=? WHERE `key`='db_version'",
+                             [DB_VERSION]);
+                }
+            };
+            update(v++, next);
+        }
+    });
+};
+
+function update(version, cb) {
+    setImmediate(cb);
+}