1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.internal.util.test;
18
19import android.net.Uri;
20import android.os.Bundle;
21import android.provider.Settings;
22import android.test.mock.MockContentProvider;
23import android.util.Log;
24
25import java.util.HashMap;
26
27/**
28 * Fake for system settings.
29 *
30 * To use, ensure that the Context used by the test code returns a ContentResolver that uses this
31 * provider for the Settings authority:
32 *
33 *   class MyTestContext extends MockContext {
34 *       ...
35 *       private final MockContentResolver mContentResolver;
36 *       public MyTestContext(...) {
37 *           ...
38 *           mContentResolver = new MockContentResolver();
39 *           mContentResolver.addProvider(Settings.AUTHORITY, new FakeSettingsProvider());
40 *       }
41 *       ...
42 *       @Override
43 *       public ContentResolver getContentResolver() {
44 *           return mContentResolver;
45 *       }
46 *
47 * As long as the code under test is using the test Context, the actual code under test does not
48 * need to be modified, and can access Settings using the normal static methods:
49 *
50 *   Settings.Global.getInt(cr, "my_setting", 0);  // Returns 0.
51 *   Settings.Global.putInt(cr, "my_setting", 5);
52 *   Settings.Global.getInt(cr, "my_setting", 0);  // Returns 5.
53 *
54 * Note that this class cannot be used in the same process as real settings. This is because it
55 * works by passing an alternate ContentResolver to Settings operations. Unfortunately, the Settings
56 * class only fetches the content provider from the passed-in ContentResolver the first time it's
57 * used, and after that stores it in a per-process static.
58 *
59 * TODO: evaluate implementing settings change notifications. This would require:
60 *
61 * 1. Making ContentResolver#registerContentObserver non-final and overriding it in
62 *    MockContentResolver.
63 * 2. Making FakeSettingsProvider take a ContentResolver argument.
64 * 3. Calling ContentResolver#notifyChange(getUriFor(table, arg), ...) on every settings change.
65 */
66public class FakeSettingsProvider extends MockContentProvider {
67
68    private static final String TAG = FakeSettingsProvider.class.getSimpleName();
69    private static final boolean DBG = false;
70    private static final String[] TABLES = { "system", "secure", "global" };
71
72    private final HashMap<String, HashMap<String, String>> mTables = new HashMap<>();
73
74    public FakeSettingsProvider() {
75        for (int i = 0; i < TABLES.length; i++) {
76            mTables.put(TABLES[i], new HashMap<String, String>());
77        }
78    }
79
80    private Uri getUriFor(String table, String key) {
81        switch (table) {
82            case "system":
83                return Settings.System.getUriFor(key);
84            case "secure":
85                return Settings.Secure.getUriFor(key);
86            case "global":
87                return Settings.Global.getUriFor(key);
88            default:
89                throw new UnsupportedOperationException("Unknown settings table " + table);
90        }
91    }
92
93    public Bundle call(String method, String arg, Bundle extras) {
94        // Methods are "GET_system", "GET_global", "PUT_secure", etc.
95        String[] commands = method.split("_", 2);
96        String op = commands[0];
97        String table = commands[1];
98
99        Bundle out = new Bundle();
100        String value;
101        switch (op) {
102            case "GET":
103                value = mTables.get(table).get(arg);
104                if (value != null) {
105                    if (DBG) {
106                        Log.d(TAG, String.format("Returning fake setting %s.%s = %s",
107                                table, arg, value));
108                    }
109                    out.putString(Settings.NameValueTable.VALUE, value);
110                }
111                break;
112            case "PUT":
113                value = extras.getString(Settings.NameValueTable.VALUE, null);
114                if (DBG) {
115                    Log.d(TAG, String.format("Inserting fake setting %s.%s = %s",
116                            table, arg, value));
117                }
118                if (value != null) {
119                    mTables.get(table).put(arg, value);
120                } else {
121                    mTables.get(table).remove(arg);
122                }
123                break;
124            default:
125                throw new UnsupportedOperationException("Unknown command " + method);
126        }
127
128        return out;
129    }
130}
131