Diff: inc/core/MemberFunctionCallback.h

Revision:

1:8aa5cdb4ab67

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/inc/core/MemberFunctionCallback.h	Thu Apr 07 01:33:22 2016 +0100
@@ -0,0 +1,114 @@
+/*
+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.
+*/
+
+#ifndef MEMBER_FUNCTION_CALLBACK_H
+#define MEMBER_FUNCTION_CALLBACK_H
+
+#include "mbed.h"
+#include "MicroBitConfig.h"
+#include "MicroBitEvent.h"
+#include "MicroBitCompat.h"
+
+/**
+  * Class definition for a MemberFunctionCallback.
+  *
+  * C++ member functions (also known as methods) have a more complex
+  * representation than normal C functions. This class allows a reference to
+  * a C++ member function to be stored then called at a later date.
+  *
+  * This class is used extensively by the MicroBitMessageBus to deliver
+  * events to C++ methods.
+  */
+class MemberFunctionCallback
+{
+    private:
+    void* object;
+    uint32_t method[4];
+    void (*invoke)(void *object, uint32_t *method, MicroBitEvent e);
+    template <typename T> static void methodCall(void* object, uint32_t*method, MicroBitEvent e);
+
+    public:
+
+    /**
+      * Constructor. Creates a MemberFunctionCallback based on a pointer to given method.
+      *
+      * @param object The object the callback method should be invooked on.
+      *
+      * @param method The method to invoke.
+      */
+    template <typename T> MemberFunctionCallback(T* object, void (T::*method)(MicroBitEvent e));
+
+    /**
+      * A comparison of two MemberFunctionCallback objects.
+      *
+      * @return true if the given MemberFunctionCallback is equivalent to this one, false otherwise.
+      */
+    bool operator==(const MemberFunctionCallback &mfc);
+
+    /**
+      * Calls the method reference held by this MemberFunctionCallback.
+      *
+      * @param e The event to deliver to the method
+      */
+    void fire(MicroBitEvent e);
+};
+
+/**
+  * Constructor. Creates a MemberFunctionCallback based on a pointer to given method.
+  *
+  * @param object The object the callback method should be invooked on.
+  *
+  * @param method The method to invoke.
+  */
+template <typename T>
+MemberFunctionCallback::MemberFunctionCallback(T* object, void (T::*method)(MicroBitEvent e))
+{
+    this->object = object;
+    memclr(this->method, sizeof(this->method));
+    memcpy(this->method, &method, sizeof(method));
+    invoke = &MemberFunctionCallback::methodCall<T>;
+}
+
+/**
+  * A template used to create a static method capable of invoking a C++ member function (method)
+  * based on the given parameters.
+  *
+  * @param object The object the callback method should be invooked on.
+  *
+  * @param method The method to invoke.
+  *
+  * @param method The MicroBitEvent to supply to the given member function.
+  */
+template <typename T>
+void MemberFunctionCallback::methodCall(void *object, uint32_t *method, MicroBitEvent e)
+{
+    T* o = (T*)object;
+    void (T::*m)(MicroBitEvent);
+    memcpy(&m, method, sizeof(m));
+
+    (o->*m)(e);
+}
+
+#endif