Merge pull request #5300 from pan-/ble-pal-event-queue

Ble pal event queue

features/FEATURE_BLE/ble/pal/EventQueue.h

@@ -0,0 +1,68 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017-2017 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 BLE_PAL_EVENT_QUEUE_H_
+#define BLE_PAL_EVENT_QUEUE_H_
+
+#include "platform/Callback.h"
+
+namespace ble {
+namespace pal {
+
+/**
+ * Simple interface which allow upper layer to post an event into the event
+ * mechanism of the abstracted stack.
+ *
+ * When an event is posted then it's availability shall be signaled to the upper
+ * layer in order to inform the upper layer that events are ready to be
+ * processed.
+ *
+ * Implementation can realize that operation by calling the function
+ * signalEventsToProcess of their implementation of BLEInstanceBase.
+ *
+ * Events in the queue shall be processed at the next invocation of
+ * BLEInstanceBase::processEvents.
+ */
+struct EventQueue {
+    /**
+     * Base constructor of an event queue.
+     */
+    EventQueue() { }
+
+    /**
+     * Destructor, needs to be overiden in implementation
+     */
+    ~EventQueue() { }
+
+    /**
+     * Post an event into the event queue.
+     *
+     * @param event The event to store in the queue, it shall be processed at
+     * the next invocation of BLE::processEvent.
+     *
+     * @return true in case of success and false otherwise
+     *
+     * @important Event availability shall be signaled to the upper layer and
+     * the event queue shall be processed at the next invocation of
+     * BLEInstanceBase::process
+     */
+    virtual bool post(const mbed::Callback<void()>& event) = 0;
+};
+
+} // namespace pal
+} // namespace ble
+
+#endif /* BLE_PAL_EVENT_QUEUE_H_ */

features/FEATURE_BLE/ble/pal/SimpleEventQueue.h

@@ -0,0 +1,143 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017-2017 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 BLE_PAL_SIMPLE_EVENT_QUEUE_H_
+#define BLE_PAL_SIMPLE_EVENT_QUEUE_H_
+
+#include <new>
+#include "EventQueue.h"
+#include "ble/BLEInstanceBase.h"
+#include "BLE/ble.h"
+
+namespace ble {
+namespace pal {
+
+/**
+ * Simple implementation of the pal::EventQueue.
+ */
+struct SimpleEventQueue : EventQueue {
+
+    typedef mbed::Callback<void()> event_t;
+
+    /**
+     * Construct an empty event queue.
+     *
+     * @important a call to initialize is mandatory before any other call.
+     *
+     * @param ble_instance_id The id of the ble instance associated with that
+     * event queue.
+     */
+    SimpleEventQueue() :
+        _ble_base(NULL), _ble_instance_id(0), _events(NULL) { }
+
+    /**
+     * Initialize the event queue with a BLEInstanceBase and a ble id.
+     *
+     * @param ble_base the instance which will be used to signal the presence
+     * of new events.
+     *
+     * @param ble_id Id of the BLE instance using that event queue.
+     */
+    void initialize(BLEInstanceBase* ble_base, BLE::InstanceID_t ble_id)
+    {
+        _ble_base = ble_base;
+        _ble_instance_id = ble_id;
+    }
+
+    /**
+     * @see ble::pal::EventQueue
+     */
+    ~SimpleEventQueue()
+    {
+        clear();
+    }
+
+    /**
+     * @see ble::pal::post
+     */
+    virtual bool post(const mbed::Callback<void()>& event)
+    {
+        if (_ble_base == NULL) {
+            return false;
+        }
+
+        EventNode* next = new (std::nothrow) EventNode(event);
+        if (next == NULL) {
+            return false;
+        }
+
+        if (_events == NULL) {
+            _events = next;
+        } else {
+            EventNode* previous = _events;
+            while (previous->next) {
+                previous = previous->next;
+            }
+
+            previous->next = next;
+        }
+
+        signal_event();
+
+        return true;
+    }
+
+    /**
+     * Clear the event queue from all its events.
+     */
+    void clear()
+    {
+        while (_events) {
+            EventNode* next = _events->next;
+            delete _events;
+            _events = next;
+        }
+    }
+
+    /**
+     * Process the event queue.
+     */
+    void process()
+    {
+        while (_events) {
+            EventNode* next = _events->next;
+            _events->event();
+            delete _events;
+            _events = next;
+        }
+    }
+
+private:
+    struct EventNode {
+        EventNode(const event_t event) : event(event), next(NULL) { }
+        event_t event;
+        EventNode* next;
+    };
+
+    void signal_event()
+    {
+        _ble_base->signalEventsToProcess(_ble_instance_id);
+    }
+
+    BLEInstanceBase* _ble_base;
+    BLE::InstanceID_t _ble_instance_id;
+    EventNode* _events;
+};
+
+} // namespace pal
+} // namespace ble
+
+#endif /* BLE_PAL_SIMPLE_EVENT_QUEUE_H_ */