From 255e933379250234ef4c153d6654b83c37f968e5 Mon Sep 17 00:00:00 2001
From: Laurent Monin <zas@norz.org>
Date: Thu, 11 Jun 2015 14:25:58 +0200
Subject: [PATCH] mblinks: take care of removal of old cache versions

---
 lib/mblinks.js | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/lib/mblinks.js b/lib/mblinks.js
index c8c1325..576b929 100644
--- a/lib/mblinks.js
+++ b/lib/mblinks.js
@@ -13,9 +13,9 @@
 //  mblinks.searchAndDisplayMbLink(album_link, 'release', function (link) { $('div#there').after(link); } );
 // }
 
-// cachekey = textual key used to store cached data in local storage
+// user_cache_key = textual key used to store cached data in local storage
 // expiration = time in minutes before an entry is refreshed, value <= 0 disables cache reads
-var MBLinks = function (cachekey, expiration) {
+var MBLinks = function (user_cache_key, expiration) {
   this.supports_local_storage = function () {
     try {
       return !!localStorage.getItem;
@@ -58,7 +58,8 @@ var MBLinks = function (cachekey, expiration) {
   this.cache = {};
   this.expirationMinutes = parseInt(expiration, 10);
   var cache_version = 2;
-  this.cache_key = cachekey + '-v' + cache_version;
+  this.user_cache_key = user_cache_key;
+  this.cache_key = this.user_cache_key + '-v' + cache_version;
   this.mb_server = '//musicbrainz.org';
   // overrides link title and img src url (per type), see createMusicBrainzLink()
   this.type_link_info = {
@@ -85,6 +86,8 @@ var MBLinks = function (cachekey, expiration) {
     this.cache = JSON.parse(localStorage.getItem(this.cache_key) || '{}');
     // remove old entries
     this.clearCacheExpired();
+    // remove old cache versions
+    this.removeOldCacheVersions();
   };
 
   this.saveCache = function () {
@@ -96,6 +99,22 @@ var MBLinks = function (cachekey, expiration) {
     }
   };
 
+  this.removeOldCacheVersions = function () {
+    var to_remove = [];
+    for (var i = 0, len = localStorage.length; i < len; ++i) {
+      var key = localStorage.key(i);
+      if (key.indexOf(this.user_cache_key) === 0) {
+        if (key != this.cache_key) { // we don't want to remove current cache
+          to_remove.push(key);
+        }
+      }
+    }
+    // remove old cache keys
+    for (var i = 0; i < to_remove.length; i++) {
+      localStorage.removeItem(to_remove[i]);
+    }
+  };
+
   this.clearCacheExpired = function() {
     //var old_cache_entries = Object.keys(this.cache).length;
     //console.log("clearCacheExpired " + old_cache_entries);