LinkLossService.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __BLE_LINK_LOSS_SERVICE_H__
00018 #define __BLE_LINK_LOSS_SERVICE_H__
00019 
00020 #include "Gap.h"
00021 
00022 /**
00023 * @class LinkLossService
00024 * @brief This service defines behavior when a link is lost between two devices. <br>
00025 * Service:  https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.link_loss.xml <br>
00026 * Alertness Level Char: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.alert_level.xml <br>
00027 */
00028 class LinkLossService {
00029 public:
00030     enum AlertLevel_t {
00031         NO_ALERT   = 0,
00032         MILD_ALERT = 1,
00033         HIGH_ALERT = 2
00034     };
00035 
00036     typedef void (* callback_t)(AlertLevel_t level);
00037 
00038     /**
00039      * @param[ref] ble
00040      *                 BLEDevice object for the underlying controller.
00041      */
00042     LinkLossService (BLEDevice &bleIn, callback_t callbackIn, AlertLevel_t levelIn = NO_ALERT) :
00043         ble(bleIn),
00044         alertLevel(levelIn),
00045         callback(callbackIn),
00046         alertLevelChar(GattCharacteristic::UUID_ALERT_LEVEL_CHAR, reinterpret_cast<uint8_t *>(&alertLevel), sizeof(uint8_t), sizeof(uint8_t),
00047                        GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE) {
00048         static bool serviceAdded = false; /* We should only ever add one LinkLoss service. */
00049         if (serviceAdded) {
00050             return;
00051         }
00052 
00053         GattCharacteristic *charTable[] = {&alertLevelChar};
00054         GattService         linkLossService(GattService::UUID_LINK_LOSS_SERVICE, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
00055 
00056         ble.addService(linkLossService);
00057         serviceAdded = true;
00058 
00059         ble.addToDisconnectionCallChain(this, &LinkLossService::onDisconnectionFilter);
00060         ble.onDataWritten(this, &LinkLossService::onDataWritten);
00061     }
00062 
00063     /**
00064      * Update the callback.
00065      */
00066     void setCallback(callback_t newCallback) {
00067         callback = newCallback;
00068     }
00069 
00070     /**
00071      * Update Alertness Level.
00072      */
00073     void setAlertLevel(AlertLevel_t newLevel) {
00074         alertLevel = newLevel;
00075     }
00076 
00077 private:
00078     /**
00079      * This callback allows receiving updates to the AlertLevel Characteristic.
00080      *
00081      * @param[in] params
00082      *     Information about the characterisitc being updated.
00083      */
00084     virtual void onDataWritten(const GattCharacteristicWriteCBParams *params) {
00085         if (params->charHandle == alertLevelChar.getValueHandle()) {
00086             alertLevel = *reinterpret_cast<const AlertLevel_t *>(params->data);
00087         }
00088     }
00089 
00090     void onDisconnectionFilter(void) {
00091         if (alertLevel != NO_ALERT) {
00092             callback(alertLevel);
00093         }
00094     }
00095 
00096 private:
00097     BLEDevice          &ble;
00098     AlertLevel_t        alertLevel;
00099     callback_t          callback;
00100     GattCharacteristic  alertLevelChar;
00101 };
00102 
00103 #endif /* __BLE_LINK_LOSS_SERVICE_H__ */