The Tor Browser: addon-sdk/source/lib/sdk/system/environment.js@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* This Source Code Form is subject to the terms of the Mozilla Public

     2  * License, v. 2.0. If a copy of the MPL was not distributed with this

     3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     5 'use strict';

     7 module.metadata = {

     8   "stability": "stable"

     9 };

    11 const { Cc, Ci } = require('chrome');

    12 const { get, set, exists } = Cc['@mozilla.org/process/environment;1'].

    13                              getService(Ci.nsIEnvironment);

    15 exports.env = Proxy.create({

    16   // XPCOM does not provides a way to enumerate environment variables, so we

    17   // just don't support enumeration.

    18   getPropertyNames: function() [],

    19   getOwnPropertyNames: function() [],

    20   enumerate: function() [],

    21   keys: function() [],

    22   // We do not support freezing, cause it would make it impossible to set new

    23   // environment variables.

    24   fix: function() undefined,

    25   // We present all environment variables as own properties of this object,

    26   // so we just delegate this call to `getOwnPropertyDescriptor`.

    27   getPropertyDescriptor: function(name) this.getOwnPropertyDescriptor(name),

    28   // If environment variable with this name is defined, we generate proprety

    29   // descriptor for it, otherwise fall back to `undefined` so that for consumer

    30   // this property does not exists.

    31   getOwnPropertyDescriptor: function(name) {

    32     return !exists(name) ? undefined : {

    33       value: get(name),

    34       enumerable: false,    // Non-enumerable as we don't support enumeration.

    35       configurable: true,   // Configurable as it may be deleted.

    36       writable: true        // Writable as we do support set.

    37     }

    38   },

    40   // New environment variables can be defined just by defining properties

    41   // on this object.

    42   defineProperty: function(name, { value }) set(name, value),

    43   delete: function(name) {

    44     set(name, null);

    45     return true;

    46   },

    48   // We present all properties as own, there for we just delegate to `hasOwn`.

    49   has: function(name) this.hasOwn(name),

    50   // We do support checks for existence of an environment variable, via `in`

    51   // operator on this object.

    52   hasOwn: function(name) exists(name),

    54   // On property get / set we do read / write appropriate environment variables,

    55   // please note though, that variables with names of standard object properties

    56   // intentionally (so that this behaves as normal object) can not be

    57   // read / set.

    58   get: function(proxy, name) Object.prototype[name] || get(name) || undefined,

    59   set: function(proxy, name, value) Object.prototype[name] || set(name, value)

    60 });

The Tor Browser / file revision