Bug 520482: Firefox should be able to remember more than 8 lightweight themes. r=robstrong

toolkit/mozapps/extensions/LightweightThemeManager.jsm

@@ -47,7 +47,7 @@ const PREF_LWTHEME_TO_SELECT = "extensions.lwThemeToSelect";
 const PREF_GENERAL_SKINS_SELECTEDSKIN = "general.skins.selectedSkin";
 const ADDON_TYPE             = "theme";
 
-const MAX_USED_THEMES_COUNT = 8;
+const DEFAULT_MAX_USED_THEMES_COUNT = 30;
 
 const MAX_PREVIEW_SECONDS = 30;
 
@@ -67,7 +67,8 @@ __defineGetter__("_prefs", function () {
   delete this._prefs;
   return this._prefs =
          Cc["@mozilla.org/preferences-service;1"]
-           .getService(Ci.nsIPrefService).getBranch("lightweightThemes.");
+           .getService(Ci.nsIPrefService).getBranch("lightweightThemes.")
+           .QueryInterface(Ci.nsIPrefBranch2);
 });
 
 __defineGetter__("_observerService", function () {
@@ -82,6 +83,22 @@ __defineGetter__("_ioService", function () {
          Cc["@mozilla.org/network/io-service;1"].getService(Ci.nsIIOService);
 });
 
+__defineGetter__("_maxUsedThemes", function() {
+  delete this._maxUsedThemes;
+  try {
+    this._maxUsedThemes = _prefs.getIntPref("maxUsedThemes");
+  }
+  catch (e) {
+    this._maxUsedThemes = DEFAULT_MAX_USED_THEMES_COUNT;
+  }
+  return this._maxUsedThemes;
+});
+
+__defineSetter__("_maxUsedThemes", function(aVal) {
+  delete this._maxUsedThemes;
+  return this._maxUsedThemes = aVal;
+});
+
 var LightweightThemeManager = {
   get usedThemes () {
     try {
@@ -266,6 +283,15 @@ var LightweightThemeManager = {
         this.themeChanged(null);
       Services.prefs.clearUserPref(PREF_LWTHEME_TO_SELECT);
     }
+
+    _prefs.addObserver("", _prefObserver, false);
+  },
+
+  /**
+   * Shuts down the provider.
+   */
+  shutdown: function() {
+    _prefs.removeObserver("", _prefObserver);
   },
 
   /**
@@ -646,7 +672,7 @@ function _makeURI(aURL, aBaseURI)
 
 function _updateUsedThemes(aList) {
   // Send uninstall events for all themes that need to be removed.
-  while (aList.length > MAX_USED_THEMES_COUNT) {
+  while (aList.length > _maxUsedThemes) {
     let wrapper = new AddonWrapper(aList[aList.length - 1]);
     AddonManagerPrivate.callAddonListeners("onUninstalling", wrapper, false);
     aList.pop();
@@ -673,6 +699,27 @@ var _previewTimerCallback = {
   }
 };
 
+var _prefObserver = {
+  /**
+   * Called when any of the lightweightThemes preferences are changed.
+   * @see nsIObserver
+   */
+  observe: function (aSubject, aTopic, aData) {
+    switch (aData) {
+      case "maxUsedThemes":
+        try {
+          _maxUsedThemes = _prefs.getIntPref(aData);
+        }
+        catch (e) {
+          _maxUsedThemes = DEFAULT_MAX_USED_THEMES_COUNT;
+        }
+        // Update the theme list to remove any themes over the number we keep
+        _updateUsedThemes(LightweightThemeManager.usedThemes);
+        break;
+    }
+  },
+};
+
 function _persistImages(aData) {
   function onSuccess(key) function () {
     let current = LightweightThemeManager.currentTheme;

toolkit/mozapps/extensions/test/xpcshell/test_LightweightThemeManager.js

@@ -6,6 +6,8 @@ const OPTIONAL = ["footerURL", "textcolor", "accentcolor", "iconURL",
                   "previewURL", "author", "description", "homepageURL",
                   "updateURL", "version"];
 
+Components.utils.import("resource://gre/modules/Services.jsm");
+
 function dummy(id) {
   return {
     id: id || Math.random().toString(),
@@ -21,6 +23,8 @@ function run_test() {
   createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "1.9");
   startupManager();
 
+  Services.prefs.setIntPref("lightweightThemes.maxUsedThemes", 8);
+
   var temp = {};
   Components.utils.import("resource://gre/modules/LightweightThemeManager.jsm", temp);
   do_check_eq(typeof temp.LightweightThemeManager, "object");
@@ -432,4 +436,79 @@ function run_test() {
   ltm.forgetUsedTheme("x1");
   do_check_eq(ltm.usedThemes.length, 0);
   do_check_eq(ltm.currentTheme, null);
+
+  Services.prefs.clearUserPref("lightweightThemes.maxUsedThemes");
+
+  ltm.currentTheme = dummy("x1");
+  ltm.currentTheme = dummy("x2");
+  ltm.currentTheme = dummy("x3");
+  ltm.currentTheme = dummy("x4");
+  ltm.currentTheme = dummy("x5");
+  ltm.currentTheme = dummy("x6");
+  ltm.currentTheme = dummy("x7");
+  ltm.currentTheme = dummy("x8");
+  ltm.currentTheme = dummy("x9");
+  ltm.currentTheme = dummy("x10");
+  ltm.currentTheme = dummy("x11");
+  ltm.currentTheme = dummy("x12");
+  ltm.currentTheme = dummy("x13");
+  ltm.currentTheme = dummy("x14");
+  ltm.currentTheme = dummy("x15");
+  ltm.currentTheme = dummy("x16");
+  ltm.currentTheme = dummy("x17");
+  ltm.currentTheme = dummy("x18");
+  ltm.currentTheme = dummy("x19");
+  ltm.currentTheme = dummy("x20");
+  ltm.currentTheme = dummy("x21");
+  ltm.currentTheme = dummy("x22");
+  ltm.currentTheme = dummy("x23");
+  ltm.currentTheme = dummy("x24");
+  ltm.currentTheme = dummy("x25");
+  ltm.currentTheme = dummy("x26");
+  ltm.currentTheme = dummy("x27");
+  ltm.currentTheme = dummy("x28");
+  ltm.currentTheme = dummy("x29");
+  ltm.currentTheme = dummy("x30");
+
+  do_check_eq(ltm.usedThemes.length, 30);
+
+  ltm.currentTheme = dummy("x31");
+
+  do_check_eq(ltm.usedThemes.length, 30);
+  do_check_eq(ltm.getUsedTheme("x1"), null);
+
+  Services.prefs.setIntPref("lightweightThemes.maxUsedThemes", 15);
+
+  do_check_eq(ltm.usedThemes.length, 15);
+
+  Services.prefs.setIntPref("lightweightThemes.maxUsedThemes", 32);
+
+  ltm.currentTheme = dummy("x1");
+  ltm.currentTheme = dummy("x2");
+  ltm.currentTheme = dummy("x3");
+  ltm.currentTheme = dummy("x4");
+  ltm.currentTheme = dummy("x5");
+  ltm.currentTheme = dummy("x6");
+  ltm.currentTheme = dummy("x7");
+  ltm.currentTheme = dummy("x8");
+  ltm.currentTheme = dummy("x9");
+  ltm.currentTheme = dummy("x10");
+  ltm.currentTheme = dummy("x11");
+  ltm.currentTheme = dummy("x12");
+  ltm.currentTheme = dummy("x13");
+  ltm.currentTheme = dummy("x14");
+  ltm.currentTheme = dummy("x15");
+  ltm.currentTheme = dummy("x16");
+
+  ltm.currentTheme = dummy("x32");
+
+  do_check_eq(ltm.usedThemes.length, 32);
+
+  ltm.currentTheme = dummy("x33");
+
+  do_check_eq(ltm.usedThemes.length, 32);
+
+  Services.prefs.clearUserPref("lightweightThemes.maxUsedThemes");
+
+  do_check_eq(ltm.usedThemes.length, 30);
 }