untested implementation of trimHistory

lib/hk-util.js

@@ -0,0 +1,24 @@
+var HK = module.exports;
+
+/*  getHash
+    * this function slices off the leading portion of a message which is
+      most likely unique
+    * these "hashes" are used to identify particular messages in a channel's history
+    * clients store "hashes" either in memory or in their drive to query for new messages:
+      * when reconnecting to a pad
+      * when connecting to chat or a mailbox
+    * thus, we can't change this function without invalidating client data which:
+      * is encrypted clientside
+      * can't be easily migrated
+    * don't break it!
+*/
+HK.getHash = function (msg, Log) {
+    if (typeof(msg) !== 'string') {
+        if (Log) {
+            Log.warn('HK_GET_HASH', 'getHash() called on ' + typeof(msg) + ': ' + msg);
+        }
+        return '';
+    }
+    return msg.slice(0,64);
+};
+