1/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2/* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5
6#include "nsISupports.idl"
7
8/**
9 * Scriptable access to the current process environment.
10 *
11 */
12[scriptable, uuid(101d5941-d820-4e85-a266-9a3469940807)]
13interface nsIEnvironment : nsISupports
14{
15    /**
16     * Set the value of an environment variable.
17     *
18     * @param aName   the variable name to set.
19     * @param aValue  the value to set.
20     */
21    void set(in AString aName, in AString aValue);
22
23    /**
24     * Get the value of an environment variable.
25     *
26     * @param aName   the variable name to retrieve.
27     * @return        returns the value of the env variable. An empty string
28     *                will be returned when the env variable does not exist or
29     *                when the value itself is an empty string - please use
30     *                |exists()| to probe whether the env variable exists
31     *                or not.
32     */
33    AString get(in AString aName);
34
35    /**
36     * Check the existence of an environment variable.
37     * This method checks whether an environment variable is present in
38     * the environment or not.
39     *
40     * - For Unix/Linux platforms we follow the Unix definition:
41     * An environment variable exists when |getenv()| returns a non-NULL value.
42     * An environment variable does not exist when |getenv()| returns NULL.
43     * - For non-Unix/Linux platforms we have to fall back to a
44     * "portable" definition (which is incorrect for Unix/Linux!!!!)
45     * which simply checks whether the string returned by |Get()| is empty
46     * or not.
47     *
48     * @param aName   the variable name to probe.
49     * @return        if the variable has been set, the value returned is
50     *                PR_TRUE. If the variable was not defined in the
51     *                environment PR_FALSE will be returned.
52     */
53    boolean exists(in AString aName);
54};
55
56