Diff: source/core/MicroBitListener.cpp

Revision:

1:8aa5cdb4ab67

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/source/core/MicroBitListener.cpp	Thu Apr 07 01:33:22 2016 +0100
@@ -0,0 +1,122 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 British Broadcasting Corporation.
+This software is provided by Lancaster University by arrangement with the BBC.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+/**
+  *	This structure defines a MicroBitListener used to invoke functions, or member
+  * functions if an instance of EventModel receives an event whose id and value
+  * match this MicroBitListener's id and value.
+  */
+#include "MicroBitConfig.h"
+#include "MicroBitListener.h"
+
+/**
+  * Constructor.
+  *
+  * Create a new Message Bus Listener.
+  *
+  * @param id The ID of the component you want to listen to.
+  *
+  * @param value The event value you would like to listen to from that component
+  *
+  * @param handler A function pointer to call when the event is detected.
+  *
+  * @param flags User specified, implementation specific flags, that allow behaviour of this events listener
+  * to be tuned.
+  */
+MicroBitListener::MicroBitListener(uint16_t id, uint16_t value, void (*handler)(MicroBitEvent), uint16_t flags)
+{
+	this->id = id;
+	this->value = value;
+	this->cb = handler;
+	this->cb_arg = NULL;
+    this->flags = flags;
+	this->next = NULL;
+    this->evt_queue = NULL;
+}
+
+/**
+  * Constructor.
+  *
+  * Create a new Message Bus Listener, this constructor accepts an additional
+  * parameter "arg", which is passed to the handler.
+  *
+  * @param id The ID of the component you want to listen to.
+  *
+  * @param value The event value you would like to listen to from that component
+  *
+  * @param handler A function pointer to call when the event is detected.
+  *
+  * @param arg A pointer to some data that will be given to the handler.
+  *
+  * @param flags User specified, implementation specific flags, that allow behaviour of this events listener
+  * to be tuned.
+  */
+MicroBitListener::MicroBitListener(uint16_t id, uint16_t value, void (*handler)(MicroBitEvent, void *), void* arg, uint16_t flags)
+{
+	this->id = id;
+	this->value = value;
+	this->cb_param = handler;
+	this->cb_arg = arg;
+    this->flags = flags | MESSAGE_BUS_LISTENER_PARAMETERISED;
+	this->next = NULL;
+    this->evt_queue = NULL;
+}
+
+/**
+  * Destructor. Ensures all resources used by this listener are freed.
+  */
+MicroBitListener::~MicroBitListener()
+{
+    if(this->flags & MESSAGE_BUS_LISTENER_METHOD)
+        delete cb_method;
+}
+
+/**
+  * Queues and event up to be processed.
+  *
+  * @param e The event to queue
+  */
+void MicroBitListener::queue(MicroBitEvent e)
+{
+    int queueDepth;
+
+    MicroBitEventQueueItem *p = evt_queue;
+
+    if (evt_queue == NULL)
+        evt_queue = new MicroBitEventQueueItem(e);
+    else
+    {
+        queueDepth = 1;
+
+        while (p->next != NULL)
+        {
+            p = p->next;
+            queueDepth++;
+        }
+
+        if (queueDepth < MESSAGE_BUS_LISTENER_MAX_QUEUE_DEPTH)
+            p->next = new MicroBitEventQueueItem(e);
+    }
+}