1 /*
2  * Copyright (C) 2020 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 
17 package com.android.permissioncontroller.permission.data
18 
19 import android.app.Application
20 import android.app.role.OnRoleHoldersChangedListener
21 import android.app.role.RoleManager
22 import android.os.UserHandle
23 import androidx.annotation.GuardedBy
24 import com.android.permissioncontroller.PermissionControllerApplication
25 
26 /**
27  * Serves as a single shared Role Change Listener.
28  */
29 object RoleListenerMultiplexer : OnRoleHoldersChangedListener {
30 
31     private val app: Application = PermissionControllerApplication.get()
32 
33     @GuardedBy("lock")
34     private val callbacks = mutableMapOf<UserHandle,
35             MutableMap<String, MutableList<RoleHoldersChangeCallback>>>()
36 
37     private val roleManager = app.getSystemService(RoleManager::class.java)!!
38 
39     private val lock = Object()
40 
41     override fun onRoleHoldersChanged(roleName: String, user: UserHandle) {
42         val callbacksCopy: List<RoleHoldersChangeCallback>?
43         synchronized(lock) {
44             callbacksCopy = callbacks[user]?.get(roleName)?.toList()
45         }
46         callbacksCopy?.forEach { listener ->
47             listener.onRoleHoldersChanged()
48         }
49     }
50 
51     fun addCallback(roleName: String, user: UserHandle, callback: RoleHoldersChangeCallback) {
52         val wasEmpty: Boolean
53         synchronized(lock) {
54             val userCallbacks = callbacks.getOrPut(user, { mutableMapOf() })
55             wasEmpty = userCallbacks.isEmpty()
56 
57             userCallbacks.getOrPut(roleName, { mutableListOf() }).add(callback)
58         }
59 
60         if (wasEmpty) {
61             roleManager.addOnRoleHoldersChangedListenerAsUser(app.mainExecutor, this, user)
62         }
63     }
64 
65     fun removeCallback(roleName: String, user: UserHandle, callback: RoleHoldersChangeCallback) {
66         val userCallbacksEmpty: Boolean
67         synchronized(lock) {
68             val userCallbacks = callbacks[user] ?: return
69             if (!userCallbacks.contains(roleName)) {
70                 return
71             }
72 
73             if (!userCallbacks[roleName]!!.remove(callback)) {
74                 return
75             }
76 
77             if (userCallbacks[roleName]!!.isEmpty()) {
78                 userCallbacks.remove(roleName)
79             }
80 
81             userCallbacksEmpty = userCallbacks.isEmpty()
82         }
83         if (userCallbacksEmpty) {
84             roleManager.removeOnRoleHoldersChangedListenerAsUser(this, user)
85         }
86     }
87 
88     interface RoleHoldersChangeCallback {
89         fun onRoleHoldersChanged()
90     }
91 }