Diff: ble/FunctionPointerWithContext.h

Revision:

993:4d62b7967c11

Parent:

992:ca834f7ae8ed

Child:

1042:21a86ac7f5b1

--- a/ble/FunctionPointerWithContext.h	Wed Dec 02 10:29:44 2015 +0000
+++ b/ble/FunctionPointerWithContext.h	Wed Dec 02 10:29:44 2015 +0000
@@ -18,29 +18,31 @@
 #define MBED_FUNCTIONPOINTER_WITH_CONTEXT_H
 
 #include <string.h>
+#include "SafeBool.h"
 
 /** A class for storing and calling a pointer to a static or member void function
- *  which takes a context.
+ *  that takes a context.
  */
 template <typename ContextType>
-class FunctionPointerWithContext {
+class FunctionPointerWithContext : public SafeBool<FunctionPointerWithContext<ContextType> > {
 public:
     typedef FunctionPointerWithContext<ContextType> *pFunctionPointerWithContext_t;
+    typedef const FunctionPointerWithContext<ContextType> *cpFunctionPointerWithContext_t;
     typedef void (*pvoidfcontext_t)(ContextType context);
 
-    /** Create a FunctionPointerWithContext, attaching a static function
+    /** Create a FunctionPointerWithContext, attaching a static function.
      *
-     *  @param function The void static function to attach (default is none)
+     *  @param function The void static function to attach (default is none).
      */
     FunctionPointerWithContext(void (*function)(ContextType context) = NULL) :
-        _function(NULL), _caller(NULL), _next(NULL) {
+        _memberFunctionAndPointer(), _caller(NULL), _next(NULL) {
         attach(function);
     }
 
-    /** Create a FunctionPointerWithContext, attaching a member function
+    /** Create a FunctionPointerWithContext, attaching a member function.
      *
-     *  @param object The object pointer to invoke the member function on (i.e. the this pointer)
-     *  @param function The address of the void member function to attach
+     *  @param object The object pointer to invoke the member function on (the "this" pointer).
+     *  @param function The address of the void member function to attach.
      */
     template<typename T>
     FunctionPointerWithContext(T *object, void (T::*member)(ContextType context)) :
@@ -48,19 +50,30 @@
         attach(object, member);
     }
 
-    /** Attach a static function
+    FunctionPointerWithContext(const FunctionPointerWithContext& that) : 
+        _memberFunctionAndPointer(that._memberFunctionAndPointer), _caller(that._caller), _next(NULL) {
+    }
+
+    FunctionPointerWithContext& operator=(const FunctionPointerWithContext& that) {
+        _memberFunctionAndPointer = that._memberFunctionAndPointer;
+        _caller = that._caller; 
+        _next = NULL;
+        return *this;
+    }
+
+    /** Attach a static function.
      *
-     *  @param function The void static function to attach (default is none)
+     *  @param function The void static function to attach (default is none).
      */
     void attach(void (*function)(ContextType context) = NULL) {
         _function = function;
         _caller = functioncaller;
     }
 
-    /** Attach a member function
+    /** Attach a member function.
      *
-     *  @param object The object pointer to invoke the member function on (i.e. the this pointer)
-     *  @param function The address of the void member function to attach
+     *  @param object The object pointer to invoke the member function on (the "this" pointer).
+     *  @param function The address of the void member function to attach.
      */
     template<typename T>
     void attach(T *object, void (T::*member)(ContextType context)) {
@@ -69,21 +82,37 @@
         _caller = &FunctionPointerWithContext::membercaller<T>;
     }
 
-    /** Call the attached static or member function; and if there are chained
+    /** Call the attached static or member function; if there are chained
      *  FunctionPointers their callbacks are invoked as well.
-     *  @Note: all chained callbacks stack up; so hopefully there won't be too
+     *  @Note: All chained callbacks stack up, so hopefully there won't be too
      *  many FunctionPointers in a chain. */
-    void call(ContextType context) {
+    void call(ContextType context) const {
         _caller(this, context);
-
-        /* Propagate the call to next in the chain. */
-        if (_next) {
-            _next->call(context);
-        }
     }
 
     /**
-     * Setup an external FunctionPointer as a next in the chain of related
+     * @brief Same as above
+     */
+    void operator()(ContextType context) const {
+        call(context);
+    }
+
+    /** Same as above, workaround for mbed os FunctionPointer implementation. */
+    void call(ContextType context) {
+        ((const FunctionPointerWithContext*)  this)->call(context);
+    }
+
+    typedef void (FunctionPointerWithContext::*bool_type)() const;
+
+    /** 
+     * implementation of safe bool operator
+     */
+    bool toBool() const {
+        return (_function || _memberFunctionAndPointer._object);
+    }
+
+    /**
+     * Set up an external FunctionPointer as a next in the chain of related
      * callbacks. Invoking call() on the head FunctionPointer will invoke all
      * chained callbacks.
      *
@@ -101,9 +130,18 @@
         return (pvoidfcontext_t)_function;
     }
 
+    friend bool operator==(const FunctionPointerWithContext& lhs, const FunctionPointerWithContext& rhs) {
+        return rhs._caller == lhs._caller &&
+               memcmp(
+                   &rhs._memberFunctionAndPointer, 
+                   &lhs._memberFunctionAndPointer, 
+                   sizeof(rhs._memberFunctionAndPointer)
+               ) == 0;
+    }
+
 private:
     template<typename T>
-    static void membercaller(pFunctionPointerWithContext_t self, ContextType context) {
+    static void membercaller(cpFunctionPointerWithContext_t self, ContextType context) {
         if (self->_memberFunctionAndPointer._object) {
             T *o = static_cast<T *>(self->_memberFunctionAndPointer._object);
             void (T::*m)(ContextType);
@@ -112,7 +150,7 @@
         }
     }
 
-    static void functioncaller(pFunctionPointerWithContext_t self, ContextType context) {
+    static void functioncaller(cpFunctionPointerWithContext_t self, ContextType context) {
         if (self->_function) {
             self->_function(context);
         }
@@ -120,7 +158,7 @@
 
     struct MemberFunctionAndPtr {
         /*
-         * forward declaration of a class and a member function to this class.
+         * Forward declaration of a class and a member function to this class.
          * Because the compiler doesn't know anything about the forwarded member
          * function, it will always use the biggest size and the biggest alignment
          * that a member function can take for objects of type UndefinedMemberFunction.
@@ -136,20 +174,39 @@
     };
 
     union {
-        pvoidfcontext_t _function;                      /**< static function pointer - NULL if none attached */
+        pvoidfcontext_t _function;                      /**< Static function pointer - NULL if none attached */
         /**
          * object this pointer and pointer to member -
          * _memberFunctionAndPointer._object will be NULL if none attached
          */
-        MemberFunctionAndPtr _memberFunctionAndPointer;
+        mutable MemberFunctionAndPtr _memberFunctionAndPointer;
     };
 
-    void (*_caller)(FunctionPointerWithContext*, ContextType);
+    void (*_caller)(const FunctionPointerWithContext*, ContextType);
 
-    pFunctionPointerWithContext_t _next;                /**< Optional link to make a chain out of functionPointers; this
+    pFunctionPointerWithContext_t _next;                /**< Optional link to make a chain out of functionPointers. This
                                                          *   allows chaining function pointers without requiring
-                                                         *   external memory to manage the chain. Also refer to
+                                                         *   external memory to manage the chain. Refer to
                                                          *   'CallChain' as an alternative. */
 };
 
+/**
+ * @brief Create a new FunctionPointerWithContext which bind an instance and a  
+ * a member function together.
+ * @details This little helper is a just here to eliminate the need to write the
+ * FunctionPointerWithContext type each time you want to create one by kicking 
+ * automatic type deduction of function templates. With this function, it is easy 
+ * to write only one entry point for functions which expect a FunctionPointer 
+ * in parameters.
+ * 
+ * @param object to bound with member function
+ * @param member The member function called
+ * @return a new FunctionPointerWithContext
+ */
+template<typename T, typename ContextType>
+FunctionPointerWithContext<ContextType> makeFunctionPointer(T *object, void (T::*member)(ContextType context)) 
+{
+    return FunctionPointerWithContext<ContextType>(object, member);
+}
+
 #endif // ifndef MBED_FUNCTIONPOINTER_WITH_CONTEXT_H
\ No newline at end of file