Bug 1029097 - ViewHelpers.Prefs should have a way of clearing the cached preferences, r=rcampbell

browser/devtools/netmonitor/test/browser_net_prefs-and-l10n.js

@@ -35,7 +35,7 @@ function test() {
     function testPrefs() {
       let { Prefs } = aMonitor.panelWin;
 
-      is(Prefs.root, "devtools.netmonitor",
+      is(Prefs._root, "devtools.netmonitor",
         "The preferences object should have a correct root path.");
 
       is(Prefs.networkDetailsWidth,

browser/devtools/shared/test/browser.ini

@@ -31,6 +31,7 @@ support-files =
 [browser_layoutHelpers-getBoxQuads.js]
 [browser_observableobject.js]
 [browser_outputparser.js]
+[browser_prefs.js]
 [browser_require_basic.js]
 [browser_spectrum.js]
 [browser_tableWidget_basic.js]

browser/devtools/shared/test/browser_prefs.js

@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that ViewHelpers.Prefs work properly.
+
+let {ViewHelpers} = Cu.import("resource:///modules/devtools/ViewHelpers.jsm", {});
+
+function test() {
+  let Prefs = new ViewHelpers.Prefs("devtools.debugger", {
+    "foo": ["Bool", "enabled"]
+  });
+
+  let originalPrefValue = Services.prefs.getBoolPref("devtools.debugger.enabled");
+  is(Prefs.foo, originalPrefValue, "The pref value was correctly fetched.");
+
+  Prefs.foo = !originalPrefValue;
+  is(Prefs.foo, !originalPrefValue,
+    "The pref was was correctly changed (1).");
+  is(Services.prefs.getBoolPref("devtools.debugger.enabled"), !originalPrefValue,
+    "The pref was was correctly changed (2).");
+
+  Services.prefs.setBoolPref("devtools.debugger.enabled", originalPrefValue);
+  info("The pref value was reset.");
+
+  is(Prefs.foo, !originalPrefValue,
+    "The cached pref value hasn't changed yet.");
+
+  Prefs.refresh();
+  is(Prefs.foo, originalPrefValue,
+    "The cached pref value has changed now.");
+
+  finish();
+}

browser/devtools/shared/widgets/ViewHelpers.jsm

@@ -394,7 +394,8 @@ ViewHelpers.L10N.prototype = {
  *        An object containing { accessorName: [prefType, prefName] } keys.
  */
 ViewHelpers.Prefs = function(aPrefsRoot = "", aPrefsObject = {}) {
-  this.root = aPrefsRoot;
+  this._root = aPrefsRoot;
+  this._cache = new Map();
 
   for (let accessorName in aPrefsObject) {
     let [prefType, prefName] = aPrefsObject[accessorName];
@@ -411,10 +412,13 @@ ViewHelpers.Prefs.prototype = {
    * @return any
    */
   _get: function(aType, aPrefName) {
-    if (this[aPrefName] === undefined) {
-      this[aPrefName] = Services.prefs["get" + aType + "Pref"](aPrefName);
+    let cachedPref = this._cache.get(aPrefName);
+    if (cachedPref !== undefined) {
+      return cachedPref;
     }
-    return this[aPrefName];
+    let value = Services.prefs["get" + aType + "Pref"](aPrefName);
+    this._cache.set(aPrefName, value);
+    return value;
   },
 
   /**
@@ -426,7 +430,7 @@ ViewHelpers.Prefs.prototype = {
    */
   _set: function(aType, aPrefName, aValue) {
     Services.prefs["set" + aType + "Pref"](aPrefName, aValue);
-    this[aPrefName] = aValue;
+    this._cache.set(aPrefName, aValue);
   },
 
   /**
@@ -446,9 +450,16 @@ ViewHelpers.Prefs.prototype = {
     }
 
     Object.defineProperty(this, aAccessorName, {
-      get: () => aSerializer.in(this._get(aType, [this.root, aPrefName].join("."))),
-      set: (e) => this._set(aType, [this.root, aPrefName].join("."), aSerializer.out(e))
+      get: () => aSerializer.in(this._get(aType, [this._root, aPrefName].join("."))),
+      set: (e) => this._set(aType, [this._root, aPrefName].join("."), aSerializer.out(e))
     });
+  },
+
+  /**
+   * Clears all the cached preferences' values.
+   */
+  refresh: function() {
+    this._cache.clear();
   }
 };