1 /*
2  * Copyright 2024 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 // @file:JvmName("BleScanSettingListener")
18 
19 package com.android.server.bluetooth
20 
21 import android.content.ContentResolver
22 import android.database.ContentObserver
23 import android.os.Handler
24 import android.os.Looper
25 import android.provider.Settings
26 
27 private const val TAG = "BleScanSettingListener"
28 
29 object BleScanSettingListener {
30     // Must match Settings.Global.BLE_SCAN_ALWAYS_AVAILABLE but cannot depend on the variable
31     const val BLE_SCAN_ALWAYS_AVAILABLE = "ble_scan_always_enabled"
32 
33     @JvmStatic
34     var isScanAllowed = false
35         private set
36 
37     /**
38      * Listen on Ble Scan setting and trigger the callback when scanning is no longer enabled
39      *
40      * @param callback: The callback to trigger when there is a mode change, pass new mode as
41      *   parameter
42      * @return The initial value of the radio
43      */
44     @JvmStatic
initializenull45     fun initialize(looper: Looper, resolver: ContentResolver, callback: () -> Unit) {
46         val notifyForDescendants = false
47 
48         resolver.registerContentObserver(
49             Settings.Global.getUriFor(BLE_SCAN_ALWAYS_AVAILABLE),
50             notifyForDescendants,
51             object : ContentObserver(Handler(looper)) {
52                 override fun onChange(selfChange: Boolean) {
53                     val previousValue = isScanAllowed
54                     isScanAllowed = getScanSettingValue(resolver)
55                     if (isScanAllowed) {
56                         Log.i(TAG, "Ble Scan mode is now allowed. Nothing to do")
57                         return
58                     } else if (previousValue == isScanAllowed) {
59                         Log.i(TAG, "Ble Scan mode was already considered as false. Discarding")
60                         return
61                     } else {
62                         Log.i(TAG, "Trigger callback to disable BLE_ONLY mode")
63                         callback()
64                     }
65                 }
66             }
67         )
68         isScanAllowed = getScanSettingValue(resolver)
69     }
70 
71     /**
72      * Check if Bluetooth is impacted by the radio and fetch global mode status
73      *
74      * @return whether Bluetooth should consider this radio or not
75      */
getScanSettingValuenull76     private fun getScanSettingValue(resolver: ContentResolver): Boolean {
77         try {
78             return Settings.Global.getInt(resolver, BLE_SCAN_ALWAYS_AVAILABLE) != 0
79         } catch (e: Settings.SettingNotFoundException) {
80             Log.i(TAG, "Settings not found. Default to false")
81             return false
82         }
83     }
84 }
85