1 files changed, 137 insertions, 0 deletions
diff --git a/toolkit/jetpack/sdk/preferences/service.js b/toolkit/jetpack/sdk/preferences/service.js
new file mode 100644
index 0000000000..231cd8e140
--- /dev/null
+++ b/toolkit/jetpack/sdk/preferences/service.js
@@ -0,0 +1,137 @@
+/* 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/. */
+"use strict";
+
+module.metadata = {
+  "stability": "unstable"
+};
+
+// The minimum and maximum integers that can be set as preferences.
+// The range of valid values is narrower than the range of valid JS values
+// because the native preferences code treats integers as NSPR PRInt32s,
+// which are 32-bit signed integers on all platforms.
+const MAX_INT = 0x7FFFFFFF;
+const MIN_INT = -0x80000000;
+
+const {Cc,Ci,Cr} = require("chrome");
+
+const prefService = Cc["@mozilla.org/preferences-service;1"].
+                getService(Ci.nsIPrefService);
+const prefSvc = prefService.getBranch(null);
+const defaultBranch = prefService.getDefaultBranch(null);
+
+const { Preferences } = require("resource://gre/modules/Preferences.jsm");
+const prefs = new Preferences({});
+
+const branchKeys = branchName =>
+  keys(branchName).map($ => $.replace(branchName, ""));
+
+const Branch = function(branchName) {
+  return new Proxy(Branch.prototype, {
+    getOwnPropertyDescriptor(target, name, receiver) {
+      return {
+        configurable: true,
+        enumerable: true,
+        writable: false,
+        value: this.get(target, name, receiver)
+      };
+    },
+    ownKeys(target) {
+      return branchKeys(branchName);
+    },
+    get(target, name, receiver) {
+      return get(`${branchName}${name}`);
+    },
+    set(target, name, value, receiver) {
+      set(`${branchName}${name}`, value);
+      return true;
+    },
+    has(target, name) {
+      return this.hasOwn(target, name);
+    },
+    hasOwn(target, name) {
+      return has(`${branchName}${name}`);
+    },
+    deleteProperty(target, name) {
+      reset(`${branchName}${name}`);
+      return true;
+    }
+  });
+}
+
+
+function get(name, defaultValue) {
+  return prefs.get(name, defaultValue);
+}
+exports.get = get;
+
+
+function set(name, value) {
+  var prefType;
+  if (typeof value != "undefined" && value != null)
+    prefType = value.constructor.name;
+
+  switch (prefType) {
+  case "Number":
+    if (value % 1 != 0)
+      throw new Error("cannot store non-integer number: " + value);
+  }
+
+  prefs.set(name, value);
+}
+exports.set = set;
+
+const has = prefs.has.bind(prefs)
+exports.has = has;
+
+function keys(root) {
+  return prefSvc.getChildList(root);
+}
+exports.keys = keys;
+
+const isSet = prefs.isSet.bind(prefs);
+exports.isSet = isSet;
+
+function reset(name) {
+  try {
+    prefSvc.clearUserPref(name);
+  }
+  catch (e) {
+    // The pref service throws NS_ERROR_UNEXPECTED when the caller tries
+    // to reset a pref that doesn't exist or is already set to its default
+    // value.  This interface fails silently in those cases, so callers
+    // can unconditionally reset a pref without having to check if it needs
+    // resetting first or trap exceptions after the fact.  It passes through
+    // other exceptions, however, so callers know about them, since we don't
+    // know what other exceptions might be thrown and what they might mean.
+    if (e.result != Cr.NS_ERROR_UNEXPECTED) {
+      throw e;
+    }
+  }
+}
+exports.reset = reset;
+
+function getLocalized(name, defaultValue) {
+  let value = null;
+  try {
+    value = prefSvc.getComplexValue(name, Ci.nsIPrefLocalizedString).data;
+  }
+  finally {
+    return value || defaultValue;
+  }
+}
+exports.getLocalized = getLocalized;
+
+function setLocalized(name, value) {
+  // We can't use `prefs.set` here as we have to use `getDefaultBranch`
+  // (instead of `getBranch`) in order to have `mIsDefault` set to true, here:
+  // http://mxr.mozilla.org/mozilla-central/source/modules/libpref/src/nsPrefBranch.cpp#233
+  // Otherwise, we do not enter into this expected condition:
+  // http://mxr.mozilla.org/mozilla-central/source/modules/libpref/src/nsPrefBranch.cpp#244
+  defaultBranch.setCharPref(name, value);
+}
+exports.setLocalized = setLocalized;
+
+exports.Branch = Branch;
+