Diff: microbit/microbit-dal/nRF51822/source/nRF5xCharacteristicDescriptorDiscoverer.h

Revision:

0:b9164b348919

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+++ b/microbit/microbit-dal/nRF51822/source/nRF5xCharacteristicDescriptorDiscoverer.h	Mon Oct 17 12:41:20 2016 +0000
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+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __NRF_CHARACTERISTIC_DESCRIPTOR_DISCOVERY_H__
+#define __NRF_CHARACTERISTIC_DESCRIPTOR_DISCOVERY_H__
+
+#include "ble/Gap.h"
+#include "ble/DiscoveredCharacteristic.h"
+#include "ble/CharacteristicDescriptorDiscovery.h"
+#include "ble/GattClient.h"
+#include "ble_gattc.h"
+
+/**
+ * @brief Manage the discovery of Characteristic descriptors
+ * @details is a bridge between BLE API and Nordic stack regarding Characteristic
+ * Descriptor discovery. The BLE API can launch, monitor and ask for termination
+ * of a discovery. The Nordic stack will provide new descriptors and indicate when
+ * the discovery is done.
+ */
+class nRF5xCharacteristicDescriptorDiscoverer
+{
+    typedef CharacteristicDescriptorDiscovery::DiscoveryCallback_t DiscoveryCallback_t;
+    typedef CharacteristicDescriptorDiscovery::TerminationCallback_t TerminationCallback_t;
+
+public:
+    /**
+     * @brief Construct a new characteristic descriptor discoverer.
+     */
+    nRF5xCharacteristicDescriptorDiscoverer();
+
+    /**
+     * @brief Destroy a characteristic descriptor discoverer.
+     */
+    ~nRF5xCharacteristicDescriptorDiscoverer();
+
+    /**
+     * Launch a new characteristic descriptor discovery for a given DiscoveredCharacteristic.
+     * @param characteristic The characteristic owning the descriptors to discover.
+     * @param discoveryCallback The callback called when a descriptor is discovered.
+     * @param terminationCallback The callback called when the discovery process end.
+     * @return BLE_ERROR_NONE if characteristic descriptor discovery is launched successfully;
+     *         else an appropriate error.
+     * @note: this will be called by BLE API side.
+     */
+    ble_error_t launch(
+        const DiscoveredCharacteristic& characteristic,
+        const DiscoveryCallback_t& discoveryCallback,
+        const TerminationCallback_t& terminationCallback
+    );
+
+    /**
+     * @brief indicate if a characteristic descriptor discovery is active for a
+     * given DiscoveredCharacteristic.
+     * @param characteristic The characteristic for whom the descriptor might be
+     * currently discovered.
+     * @return true if descriptors of characteristic are discovered, false otherwise.
+     * @note: this will be called by BLE API side.
+     */
+    bool isActive(const DiscoveredCharacteristic& characteristic) const;
+
+    /**
+     * @brief request the termination of characteristic descriptor discovery
+     * for a give DiscoveredCharacteristic
+     * @param characteristic The characteristic for whom the descriptor discovery
+     * should be stopped.
+     * @note: this will be called by BLE API side.
+     */
+    void requestTerminate(const DiscoveredCharacteristic& characteristic);
+
+    /**
+     * @brief process descriptors discovered from the Nordic stack.
+     * @param connectionHandle The connection handle upon which descriptors has been
+     * discovered.
+     * @param descriptors Discovered descriptors.
+     * @note This will be called by the Nordic stack.
+     */
+    void process(uint16_t connectionHandle, const ble_gattc_evt_desc_disc_rsp_t& descriptors);
+
+    /**
+     * @brief Called by the Nordic stack when the discovery is over.
+     * @param The connection handle upon which the discovery process is done.
+     * @param err An error if the termination is due to an error.
+     */
+    void terminate(uint16_t connectionHandle, ble_error_t err);
+
+private:
+    // protection against copy construction and assignment
+    nRF5xCharacteristicDescriptorDiscoverer(const nRF5xCharacteristicDescriptorDiscoverer&);
+    nRF5xCharacteristicDescriptorDiscoverer& operator=(const nRF5xCharacteristicDescriptorDiscoverer&);
+
+    /**
+     * @brief Discovery process, it store the DiscoveredCharacteristic, the
+     * discovery callback and the termination callback.
+     */
+    class Discovery {
+    public:
+        /**
+         * @brief Construct an empty discovery, such can be considerate as a not running discovery.
+         * @note #isEmpty function will return true
+         */
+        Discovery();
+
+        /**
+         * @brief Construct a valid discovery process.
+         *
+         * @param c the characteristic from whom descriptors will be discovered.
+         * @param dCb The discovery callback called each time a descriptor is discovered.
+         * @param tCb The termination callback called when the discovery terminate.
+         *
+         * @note #isEmpty function will return false
+         */
+        Discovery(const DiscoveredCharacteristic& c, const DiscoveryCallback_t& dCb, const TerminationCallback_t& tCb);
+
+        /**
+         * @brief Process the discovery of a descriptor.
+         *
+         * @param handle The attribute handle of the descriptor found
+         * @param uuid The UUID of the descriptor found.
+         */
+        void process(GattAttribute::Handle_t handle, const UUID& uuid);
+
+        /**
+         * @brief Terminate the discovery process.
+         *
+         * @param err Error associate with the termination
+         * @note after this call #isEmpty function will return true.
+         */
+        void terminate(ble_error_t err);
+
+        /**
+         * @brief check if the discovery process is empty or not. Empty discovery are
+         * not running.
+         *
+         * @detail Discovery are empty after:
+         *     - a default construction
+         *     - a copy construction form a default constructed
+         *     - an assignment from a default constructed Discovery
+         * @return true if the Discovery is empty and false otherwise.
+         */
+        bool isEmpty() const;
+
+        /**
+         * @brief return the characteristic from whom descriptors are discovered.
+         * @return the characteristic from whom descriptors are discovered.
+         */
+        const DiscoveredCharacteristic& getCharacteristic() const;
+
+        /**
+         * @brief equal to operator, test if two discovery process are equal
+         *
+         * @param lhs left hand side of the expression
+         * @param rhs right hand side of the expression
+         * @return true if lhs == rhs
+         */
+        friend bool operator==(const Discovery& lhs, const Discovery& rhs) {
+            return lhs.characteristic == rhs.characteristic &&
+                   lhs.onDiscovery == rhs.onDiscovery &&
+                   lhs.onTerminate == rhs.onTerminate;
+        }
+
+        /**
+         * @brief not equal to operator, test if two discovery process are not equal
+         *
+         * @param lhs left hand side of the expression
+         * @param rhs right hand side of the expression
+         * @return true if lhs != rhs
+         */
+        friend bool operator!=(const Discovery& lhs, const Discovery& rhs) {
+            return !(lhs == rhs);
+        }
+
+    private:
+        DiscoveredCharacteristic characteristic;
+        DiscoveryCallback_t onDiscovery;
+        TerminationCallback_t onTerminate;
+    };
+
+    // find a running discovery process
+    Discovery* findRunningDiscovery(const DiscoveredCharacteristic& characteristic);
+    Discovery* findRunningDiscovery(uint16_t handle);
+
+    // Called to terminate a discovery is over.
+    void terminate(Discovery* discovery, ble_error_t err);
+
+    // get one slot for a discovery process
+    Discovery* getAvailableDiscoverySlot();
+
+    // indicate if a connection is already running a discovery
+    bool isConnectionInUse(uint16_t connHandle);
+
+    // low level start of a discovery
+    static ble_error_t gattc_descriptors_discover(uint16_t connection_handle, uint16_t start_handle, uint16_t end_handle);
+
+    // count of concurrent connections which can run a descriptor discovery process
+    static const size_t MAXIMUM_CONCURRENT_CONNECTIONS_COUNT = 3;
+
+    // array of running discoveries
+    Discovery discoveryRunning[MAXIMUM_CONCURRENT_CONNECTIONS_COUNT];
+};
+
+#endif /*__NRF_CHARACTERISTIC_DESCRIPTOR_DISCOVERY_H__*/
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