First draft of an enterprise policies component

enterprisepolicies.patch

diff --git a/browser/components/enterprisepolicies/EnterprisePolicies.js b/browser/components/enterprisepolicies/EnterprisePolicies.js
new file mode 100644
--- /dev/null
+++ b/browser/components/enterprisepolicies/EnterprisePolicies.js
@@ -0,0 +1,157 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const Ci = Components.interfaces;
+const Cc = Components.classes;
+const Cr = Components.results;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/AppConstants.jsm");
+
+
+// TODO: THIS JSON WILL LIVE IN A SEPARATE FILE
+const SAMPLE_JSON = {
+  version: 1,
+  policies: {
+    "block-about-config": true,
+    "block-devtools": true,
+    "custom-homepage": "https://www.mozilla.org/firefox/new/",
+  }
+}
+
+// XPCOM BOILERPLATE
+
+// Factory object
+const EnterprisePoliciesFactory = {
+  _instance: null,
+  createInstance: function BGSF_createInstance(outer, iid) {
+    if (outer != null)
+      throw Components.results.NS_ERROR_NO_AGGREGATION;
+    return this._instance == null ?
+      this._instance = new EnterprisePoliciesManager() : this._instance;
+  }
+};
+
+// END XPCOM BOILERPLATE
+
+// Constructor
+function EnterprisePoliciesManager() {
+  this._init();
+}
+
+let hasValidCustomization = false;
+
+let Policies = {
+  blockAboutConfig: false,
+  blockDevtools: false,
+  customHomepage: null,
+};
+
+
+EnterprisePoliciesManager.prototype = {
+  // for XPCOM
+  classID:          Components.ID("{ea4e1414-779b-458b-9d1f-d18e8efbc145}"),
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver,
+                                         Ci.nsISupportsWeakReference,
+                                         Ci.nsIEnterprisePolicies]),
+
+  // redefine the default factory for XPCOMUtils
+  _xpcom_factory: EnterprisePoliciesFactory,
+
+  // nsIObserver implementation
+  observe: function BG_observe(subject, topic, data) {
+    switch (topic) {
+      case "final-ui-startup":
+        this._beforeUIStartup();
+        break;
+    }
+  },
+
+  _init() {
+    // INIT should only be used to parse the JSON, because
+    // this is running very early.
+    // Any actual work to be done by policies should be done
+    // later (and as late as possible) by using some observer.
+    // There are lots of good examples on nsBrowserGlue.js.
+    let os = Services.obs;
+    os.addObserver(this, "final-ui-startup");
+    this._parseConfiguration();
+  },
+
+  _dispose() {
+    // TODO: call dispose like in nsBrowserGlue
+    let os = Services.obs;
+    os.removeObserver(this, "final-ui-startup");
+  },
+
+  _parseConfiguration() {
+    let json = SAMPLE_JSON; // TODO: replace this by reading the file
+
+    if (json.version != 1) {
+      return;
+    }
+
+    hasValidCustomization = true;
+
+    for (let policyName of Object.keys(json.policies)) {
+      let policySetting = json.policies[policyName];
+
+      switch (policyName) {
+        case "block-about-config":
+          Policies.blockAboutConfig = (policySetting == true);
+          break;
+
+        case "block-devtools":
+          Policies.blockDevtools = (policySetting == true);
+
+        case "custom-homepage":
+          // TODO: parse URL to check if it's a valid URL
+          Policies.customHomepage = policySetting;
+          break;
+
+        // etc.
+
+        default:
+          // TODO: log unknown policy
+
+      }
+
+    }
+  },
+
+  // runs on startup, before the first window is opened)
+  _beforeUIStartup() {
+
+  },
+
+
+  // ------------------------------
+  // public nsIEnterprisePolicies members
+  // ------------------------------
+
+  isAllowed: function BG_sanitize(policy) {
+    if (!hasValidCustomization) {
+      // We assume that all policies that are checked through "isAllowed"
+      // are about restricting access to something, so if there wasn't a
+      // valid customization file, we short-circuit anything to be *allowed*
+      return true;
+    }
+
+    switch (policy) {
+      case "block-devtools":
+        return Policies.blockDevtools;
+
+      case "about:config":
+        return !Policies.blockAboutConfig;
+    }
+
+    return (Math.random() > 0.5);
+  },
+};
+
+
+var components = [EnterprisePoliciesManager];
+this.NSGetFactory = XPCOMUtils.generateNSGetFactory(components);
diff --git a/browser/components/enterprisepolicies/EnterprisePolicies.manifest b/browser/components/enterprisepolicies/EnterprisePolicies.manifest
new file mode 100644
--- /dev/null
+++ b/browser/components/enterprisepolicies/EnterprisePolicies.manifest
@@ -0,0 +1,3 @@
+component {ea4e1414-779b-458b-9d1f-d18e8efbc145} EnterprisePolicies.js
+contract @mozilla.org/browser/enterprisepolicies;1 {ea4e1414-779b-458b-9d1f-d18e8efbc145}
+category app-startup EnterprisePolicies service,@mozilla.org/browser/enterprisepolicies;1 application={ec8030f7-c20a-464f-9b0e-13a3a9e97384}
diff --git a/browser/components/enterprisepolicies/moz.build b/browser/components/enterprisepolicies/moz.build
new file mode 100644
--- /dev/null
+++ b/browser/components/enterprisepolicies/moz.build
@@ -0,0 +1,21 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Firefox", "General")
+
+XPIDL_SOURCES += [
+    'nsIEnterprisePolicies.idl',
+]
+
+XPIDL_MODULE = 'enterprisepolicies'
+
+EXTRA_COMPONENTS += [
+    'EnterprisePolicies.js',
+    'EnterprisePolicies.manifest',
+]
+
+FINAL_LIBRARY = 'browsercomps'
diff --git a/browser/components/enterprisepolicies/nsIEnterprisePolicies.idl b/browser/components/enterprisepolicies/nsIEnterprisePolicies.idl
new file mode 100644
--- /dev/null
+++ b/browser/components/enterprisepolicies/nsIEnterprisePolicies.idl
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(6a568972-cc91-4bf5-963e-3768f3319b8a)]
+interface nsIEnterprisePolicies : nsISupports
+{
+  bool isAllowed(in ACString policy);
+};
diff --git a/browser/components/moz.build b/browser/components/moz.build
--- a/browser/components/moz.build
+++ b/browser/components/moz.build
@@ -33,16 +33,17 @@ with Files('controlcenter/**'):
 
 
 DIRS += [
     'about',
     'contextualidentity',
     'customizableui',
     'dirprovider',
     'downloads',
+    'enterprisepolicies',
     'extensions',
     'feeds',
     'migration',
     'newtab',
     'originattributes',
     'places',
     'preferences',
     'privatebrowsing',
diff --git a/toolkit/modules/Services.jsm b/toolkit/modules/Services.jsm
--- a/toolkit/modules/Services.jsm
+++ b/toolkit/modules/Services.jsm
@@ -84,16 +84,17 @@ var initTable = {
   droppedLinkHandler: ["@mozilla.org/content/dropped-link-handler;1", "nsIDroppedLinkHandler"],
   els: ["@mozilla.org/eventlistenerservice;1", "nsIEventListenerService"],
   eTLD: ["@mozilla.org/network/effective-tld-service;1", "nsIEffectiveTLDService"],
   intl: ["@mozilla.org/mozintl;1", "mozIMozIntl"],
   locale: ["@mozilla.org/intl/localeservice;1", "mozILocaleService"],
   logins: ["@mozilla.org/login-manager;1", "nsILoginManager"],
   obs: ["@mozilla.org/observer-service;1", "nsIObserverService"],
   perms: ["@mozilla.org/permissionmanager;1", "nsIPermissionManager"],
+  policies: ["@mozilla.org/browser/enterprisepolicies;1", "nsIEnterprisePolicies"],
   prompt: ["@mozilla.org/embedcomp/prompt-service;1", "nsIPromptService"],
   scriptloader: ["@mozilla.org/moz/jssubscript-loader;1", "mozIJSSubScriptLoader"],
   scriptSecurityManager: ["@mozilla.org/scriptsecuritymanager;1", "nsIScriptSecurityManager"],
   storage: ["@mozilla.org/storage/service;1", "mozIStorageService"],
   domStorageManager: ["@mozilla.org/dom/localStorage-manager;1", "nsIDOMStorageManager"],
   strings: ["@mozilla.org/intl/stringbundle;1", "nsIStringBundleService"],
   telemetry: ["@mozilla.org/base/telemetry;1", "nsITelemetry"],
   tm: ["@mozilla.org/thread-manager;1", "nsIThreadManager"],
diff --git a/toolkit/modules/tests/xpcshell/test_Services.js b/toolkit/modules/tests/xpcshell/test_Services.js
--- a/toolkit/modules/tests/xpcshell/test_Services.js
+++ b/toolkit/modules/tests/xpcshell/test_Services.js
@@ -46,16 +46,17 @@ function run_test() {
   checkService("io", Ci.nsIIOService2);
   checkService("intl", Ci.mozIMozIntl);
   checkService("locale", Ci.mozILocaleService);
   checkService("logins", Ci.nsILoginManager);
   checkService("obs", Ci.nsIObserverService);
   checkService("perms", Ci.nsIPermissionManager);
   checkService("prefs", Ci.nsIPrefBranch);
   checkService("prefs", Ci.nsIPrefService);
+  checkService("policies", Ci.nsIEnterprisePolicies);
   checkService("prompt", Ci.nsIPromptService);
   checkService("scriptSecurityManager", Ci.nsIScriptSecurityManager);
   checkService("scriptloader", Ci.mozIJSSubScriptLoader);
   checkService("startup", Ci.nsIAppStartup);
   checkService("storage", Ci.mozIStorageService);
   checkService("strings", Ci.nsIStringBundleService);
   checkService("sysinfo", Ci.nsIPropertyBag2);
   checkService("telemetry", Ci.nsITelemetry);