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LinkLossService.h
1 /* mbed Microcontroller Library
2  * Copyright (c) 2006-2013 ARM Limited
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 #ifndef __BLE_LINK_LOSS_SERVICE_H__
18 #define __BLE_LINK_LOSS_SERVICE_H__
19 
20 #include "ble/Gap.h"
21 
22 #if BLE_FEATURE_GATT_SERVER
23 
24 /**
25 * @class LinkLossService
26 * @brief This service defines behavior when a link is lost between two devices.
27 * Service: https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.link_loss.xml
28 * Alertness Level Char: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.alert_level.xml
29 */
30 class LinkLossService {
31 public:
32  enum AlertLevel_t {
33  NO_ALERT = 0,
34  MILD_ALERT = 1,
35  HIGH_ALERT = 2
36  };
37 
38  typedef void (* callback_t)(AlertLevel_t level);
39 
40  /**
41  * @param bleIn
42  * BLE object for the underlying controller.
43  * @param callbackIn Callback invoked upon disconnection.
44  * @param levelIn Alert level.
45  */
46  LinkLossService(BLE &bleIn, callback_t callbackIn, AlertLevel_t levelIn = NO_ALERT) :
47  ble(bleIn),
48  alertLevel(levelIn),
49  callback(callbackIn),
50  alertLevelChar(GattCharacteristic::UUID_ALERT_LEVEL_CHAR, reinterpret_cast<uint8_t *>(&alertLevel)) {
51  static bool serviceAdded = false; /* We should only ever add one LinkLoss service. */
52  if (serviceAdded) {
53  return;
54  }
55 
56  GattCharacteristic *charTable[] = {&alertLevelChar};
57  GattService linkLossService(GattService::UUID_LINK_LOSS_SERVICE, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
58 
59  ble.gattServer().addService(linkLossService);
60  serviceAdded = true;
61 
62  ble.gap().onDisconnection(this, &LinkLossService::onDisconnectionFilter);
63  ble.gattServer().onDataWritten(this, &LinkLossService::onDataWritten);
64  }
65 
66  /**
67  * Update the callback.
68  */
69  void setCallback(callback_t newCallback) {
70  callback = newCallback;
71  }
72 
73  /**
74  * Update alertness level.
75  */
76  void setAlertLevel(AlertLevel_t newLevel) {
77  alertLevel = newLevel;
78  }
79 
80 protected:
81  /**
82  * This callback allows receiving updates to the AlertLevel characteristic.
83  *
84  * @param[in] params
85  * Information about the characteristic being updated.
86  */
87  virtual void onDataWritten(const GattWriteCallbackParams *params) {
88  if (params->handle == alertLevelChar.getValueHandle()) {
89  alertLevel = *reinterpret_cast<const AlertLevel_t *>(params->data);
90  }
91  }
92 
93  void onDisconnectionFilter(const Gap::DisconnectionCallbackParams_t *params) {
94  if (alertLevel != NO_ALERT) {
95  callback(alertLevel);
96  }
97  }
98 
99 protected:
100  BLE &ble;
101  AlertLevel_t alertLevel;
102  callback_t callback;
103 
104  ReadWriteGattCharacteristic<uint8_t> alertLevelChar;
105 };
106 
107 #endif // BLE_FEATURE_GATT_SERVER
108 
109 #endif /* __BLE_LINK_LOSS_SERVICE_H__ */
GattWriteCallbackParams::data
const uint8_t * data
Pointer to the data to write.
Definition: GattCallbackParamTypes.h:137
BLE
Abstract away BLE-capable radio transceivers or SOCs.
Definition: BLE.h:139
GattWriteCallbackParams
GATT Write event definition.
Definition: GattCallbackParamTypes.h:42
GattCharacteristic
Representation of a GattServer characteristic.
Definition: GattCharacteristic.h:94
GattCharacteristic::getValueHandle
GattAttribute::Handle_t getValueHandle(void) const
Get the characteristic&#39;s value attribute handle in the ATT table.
Definition: GattCharacteristic.h:1715
GattWriteCallbackParams::handle
GattAttribute::Handle_t handle
Handle of the attribute to which the write operation applies.
Definition: GattCallbackParamTypes.h:91
GattService
Representation of a GattServer service.
Definition: GattService.h:38
Gap::DisconnectionCallbackParams_t
Disconnection event.
Definition: Gap.h:652
GattService::UUID_LINK_LOSS_SERVICE
UUID of the Link Loss service.
Definition: GattService.h:104
ble
Entry namespace for all BLE API definitions.
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