1 //
2 //  Copyright 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 
17 #pragma once
18 
19 #include <atomic>
20 #include <functional>
21 #include <map>
22 #include <mutex>
23 
24 #include <base/macros.h>
25 #include <bluetooth/uuid.h>
26 
27 #include "service/bluetooth_instance.h"
28 #include "service/common/bluetooth/advertise_data.h"
29 #include "service/common/bluetooth/advertise_settings.h"
30 #include "service/common/bluetooth/low_energy_constants.h"
31 #include "service/common/bluetooth/scan_filter.h"
32 #include "service/common/bluetooth/scan_result.h"
33 #include "service/common/bluetooth/scan_settings.h"
34 #include "service/hal/bluetooth_gatt_interface.h"
35 
36 namespace bluetooth {
37 
38 class Adapter;
39 
40 // A LowEnergyScanner represents an application's handle to perform various
41 // Bluetooth Low Energy GAP operations. Instances cannot be created directly and
42 // should be obtained through the factory.
43 class LowEnergyScanner : private hal::BluetoothGattInterface::ScannerObserver,
44                          public BluetoothInstance {
45  public:
46   // The Delegate interface is used to notify asynchronous events related to LE
47   // scan.
48   class Delegate {
49    public:
50     Delegate() = default;
51     virtual ~Delegate() = default;
52 
53     // Called asynchronously to notify the delegate of nearby BLE advertisers
54     // found during a device scan.
55     virtual void OnScanResult(LowEnergyScanner* client,
56                               const ScanResult& scan_result) = 0;
57 
58    private:
59     DISALLOW_COPY_AND_ASSIGN(Delegate);
60   };
61 
62   // The destructor automatically unregisters this client instance from the
63   // stack.
64   ~LowEnergyScanner() override;
65 
66   // Assigns a delegate to this instance. |delegate| must out-live this
67   // LowEnergyClient instance.
68   void SetDelegate(Delegate* delegate);
69 
70   // Initiates a BLE device scan for this client using the given |settings| and
71   // |filters|. See the documentation for ScanSettings and ScanFilter for how
72   // these parameters can be configured. Return true on success, false
73   // otherwise. Please see logs for details in case of error.
74   bool StartScan(const ScanSettings& settings,
75                  const std::vector<ScanFilter>& filters);
76 
77   // Stops an ongoing BLE device scan for this client.
78   bool StopScan();
79 
80   // Returns the current scan settings.
scan_settings()81   const ScanSettings& scan_settings() const { return scan_settings_; }
82 
83   // BluetoothInstace overrides:
84   const Uuid& GetAppIdentifier() const override;
85   int GetInstanceId() const override;
86 
87   void ScanResultCallback(hal::BluetoothGattInterface* gatt_iface,
88                           const RawAddress& bda, int rssi,
89                           std::vector<uint8_t> adv_data) override;
90 
91  private:
92   friend class LowEnergyScannerFactory;
93 
94   // Constructor shouldn't be called directly as instances are meant to be
95   // obtained from the factory.
96   LowEnergyScanner(Adapter& adapter, const Uuid& uuid, int scanner_id);
97 
98   // Calls and clears the pending callbacks.
99   void InvokeAndClearStartCallback(BLEStatus status);
100   void InvokeAndClearStopCallback(BLEStatus status);
101 
102   // Raw pointer to the Bluetooth Adapter.
103   Adapter& adapter_;
104 
105   // See getters above for documentation.
106   Uuid app_identifier_;
107   int scanner_id_;
108 
109   // Protects device scan related members below.
110   std::mutex scan_fields_lock_;
111 
112   // Current scan settings.
113   ScanSettings scan_settings_;
114 
115   // If true, then this client have a BLE device scan in progress.
116   std::atomic_bool scan_started_;
117 
118   // Raw handle to the Delegate, which must outlive this LowEnergyScanner
119   // instance.
120   std::mutex delegate_mutex_;
121   Delegate* delegate_;
122 
123   DISALLOW_COPY_AND_ASSIGN(LowEnergyScanner);
124 };
125 
126 // LowEnergyScannerFactory is used to register and obtain a per-application
127 // LowEnergyScanner instance. Users should call RegisterInstance to obtain their
128 // own unique LowEnergyScanner instance that has been registered with the
129 // Bluetooth stack.
130 class LowEnergyScannerFactory
131     : private hal::BluetoothGattInterface::ScannerObserver,
132       public BluetoothInstanceFactory {
133  public:
134   // Don't construct/destruct directly except in tests. Instead, obtain a handle
135   // from an Adapter instance.
136   explicit LowEnergyScannerFactory(Adapter& adapter);
137   ~LowEnergyScannerFactory() override;
138 
139   // BluetoothInstanceFactory override:
140   bool RegisterInstance(const Uuid& app_uuid,
141                         const RegisterCallback& callback) override;
142 
143  private:
144   friend class LowEnergyScanner;
145 
146   // BluetoothGattInterface::ScannerObserver overrides:
147   void RegisterScannerCallback(const RegisterCallback& callback,
148                                const Uuid& app_uuid, uint8_t scanner_id,
149                                uint8_t status);
150 
151   // Map of pending calls to register.
152   std::mutex pending_calls_lock_;
153   std::unordered_set<Uuid> pending_calls_;
154 
155   // Raw pointer to the Adapter that owns this factory.
156   Adapter& adapter_;
157 
158   DISALLOW_COPY_AND_ASSIGN(LowEnergyScannerFactory);
159 };
160 
161 }  // namespace bluetooth
162