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Diff: inc/core/MemberFunctionCallback.h
- Revision:
- 1:8aa5cdb4ab67
diff -r fb15f7887843 -r 8aa5cdb4ab67 inc/core/MemberFunctionCallback.h --- /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