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.cellbroadcastreceiver;
18
19import android.os.IBinder;
20import android.os.ServiceManager;
21import android.util.Log;
22
23import java.lang.reflect.Field;
24import java.util.HashMap;
25import java.util.Iterator;
26import java.util.LinkedList;
27
28// This class is for replacing existing system service with the mocked service.
29public final class MockedServiceManager {
30
31    private final String TAG = MockedServiceManager.class.getSimpleName();
32
33    private final HashMap<String, IBinder> mServiceManagerMockedServices = new HashMap<>();
34
35    private final HashMap<InstanceKey, Object> mOldInstances = new HashMap<>();
36
37    private final LinkedList<InstanceKey> mInstanceKeys = new LinkedList<>();
38
39    private static class InstanceKey {
40        final Class mClass;
41        final String mInstName;
42        final Object mObj;
43
44        InstanceKey(final Class c, final String instName, final Object obj) {
45            mClass = c;
46            mInstName = instName;
47            mObj = obj;
48        }
49
50        @Override
51        public int hashCode() {
52            return (mClass.getName().hashCode() * 31 + mInstName.hashCode()) * 31;
53        }
54
55        @Override
56        public boolean equals(Object obj) {
57            if (obj == null || obj.getClass() != getClass()) {
58                return false;
59            }
60
61            InstanceKey other = (InstanceKey) obj;
62            return (other.mClass == mClass && other.mInstName.equals(mInstName)
63                    && other.mObj == mObj);
64        }
65    }
66
67    MockedServiceManager() throws Exception {
68        replaceInstance(ServiceManager.class, "sCache", null, mServiceManagerMockedServices);
69    }
70
71    void replaceService(String key, IBinder binder) {
72        mServiceManagerMockedServices.put(key, binder);
73    }
74
75    void restoreAllServices() throws Exception {
76        restoreInstances();
77    }
78
79    private synchronized void replaceInstance(final Class c, final String instanceName,
80                                             final Object obj, final Object newValue)
81            throws Exception {
82        Field field = c.getDeclaredField(instanceName);
83        field.setAccessible(true);
84
85        InstanceKey key = new InstanceKey(c, instanceName, obj);
86        if (!mOldInstances.containsKey(key)) {
87            mOldInstances.put(key, field.get(obj));
88            mInstanceKeys.add(key);
89        }
90        field.set(obj, newValue);
91    }
92
93    private synchronized void restoreInstances() throws Exception {
94        Iterator<InstanceKey> it = mInstanceKeys.descendingIterator();
95
96        while (it.hasNext()) {
97            InstanceKey key = it.next();
98            Field field = key.mClass.getDeclaredField(key.mInstName);
99            field.setAccessible(true);
100            field.set(key.mObj, mOldInstances.get(key));
101        }
102
103        mInstanceKeys.clear();
104        mOldInstances.clear();
105    }
106}
107