Diff: microbit/microbit-dal/BLE_API/ble/CallChainOfFunctionPointersWithContext.h

Revision:

0:b9164b348919

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/microbit/microbit-dal/BLE_API/ble/CallChainOfFunctionPointersWithContext.h	Mon Oct 17 12:41:20 2016 +0000
@@ -0,0 +1,238 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 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 MBED_CALLCHAIN_OF_FUNCTION_POINTERS_WITH_CONTEXT_H
+#define MBED_CALLCHAIN_OF_FUNCTION_POINTERS_WITH_CONTEXT_H
+
+#include <string.h>
+#include "FunctionPointerWithContext.h"
+#include "SafeBool.h"
+
+
+/** Group one or more functions in an instance of a CallChainOfFunctionPointersWithContext, then call them in
+ * sequence using CallChainOfFunctionPointersWithContext::call(). Used mostly by the interrupt chaining code,
+ * but can be used for other purposes.
+ *
+ * Example:
+ * @code
+ *
+ * CallChainOfFunctionPointersWithContext<void *> chain;
+ *
+ * void first(void *context) {
+ *     printf("'first' function.\n");
+ * }
+ *
+ * void second(void *context) {
+ *     printf("'second' function.\n");
+ * }
+ *
+ * class Test {
+ * public:
+ *     void f(void *context) {
+ *         printf("A::f (class member).\n");
+ *     }
+ * };
+ *
+ * int main() {
+ *     Test test;
+ *
+ *     chain.add(second);
+ *     chain.add_front(first);
+ *     chain.add(&test, &Test::f);
+ *     chain.call();
+ * }
+ * @endcode
+ */
+
+template <typename ContextType>
+class CallChainOfFunctionPointersWithContext : public SafeBool<CallChainOfFunctionPointersWithContext<ContextType> > {
+public:
+    typedef FunctionPointerWithContext<ContextType> *pFunctionPointerWithContext_t;
+
+public:
+    /** Create an empty chain.
+     *
+     *  @param size (optional) Initial size of the chain.
+     */
+    CallChainOfFunctionPointersWithContext() : chainHead(NULL) {
+        /* empty */
+    }
+
+    virtual ~CallChainOfFunctionPointersWithContext() {
+        clear();
+    }
+
+    /** Add a function at the front of the chain.
+     *
+     *  @param function A pointer to a void function.
+     *
+     *  @returns
+     *  The function object created for 'function'.
+     */
+    pFunctionPointerWithContext_t add(void (*function)(ContextType context)) {
+        return common_add(new FunctionPointerWithContext<ContextType>(function));
+    }
+
+    /** Add a function at the front of the chain.
+     *
+     *  @param tptr Pointer to the object to call the member function on.
+     *  @param mptr Pointer to the member function to be called.
+     *
+     *  @returns
+     *  The function object created for 'tptr' and 'mptr'.
+     */
+    template<typename T>
+    pFunctionPointerWithContext_t add(T *tptr, void (T::*mptr)(ContextType context)) {
+        return common_add(new FunctionPointerWithContext<ContextType>(tptr, mptr));
+    }
+
+    /** Add a function at the front of the chain.
+     *
+     *  @param func The FunctionPointerWithContext to add.
+     */
+    pFunctionPointerWithContext_t add(const FunctionPointerWithContext<ContextType>& func) {
+        return common_add(new FunctionPointerWithContext<ContextType>(func));
+    }
+
+    /** 
+     * Detach a function pointer from a callchain
+     * 
+     * @oaram toDetach FunctionPointerWithContext to detach from this callchain
+     * 
+     * @return true if a function pointer has been detached and false otherwise
+     */ 
+    bool detach(const FunctionPointerWithContext<ContextType>& toDetach) { 
+        pFunctionPointerWithContext_t current = chainHead;
+        pFunctionPointerWithContext_t previous = NULL;
+
+        while (current) {
+            if(*current == toDetach) { 
+                if(previous == NULL) {
+                    if(currentCalled == current) { 
+                        currentCalled = NULL;
+                    }
+                    chainHead = current->getNext();
+                } else {
+                    if(currentCalled == current) { 
+                        currentCalled = previous;
+                    }
+                    previous->chainAsNext(current->getNext());
+                }
+                delete current;
+                return true;
+            }
+
+            previous = current;
+            current = current->getNext();
+        }
+
+        return false;
+    }
+
+    /** Clear the call chain (remove all functions in the chain).
+     */
+    void clear(void) {
+        pFunctionPointerWithContext_t fptr = chainHead;
+        while (fptr) {
+            pFunctionPointerWithContext_t deadPtr = fptr;
+            fptr = deadPtr->getNext();
+            delete deadPtr;
+        }
+
+        chainHead = NULL;
+    }
+
+    bool hasCallbacksAttached(void) const {
+        return (chainHead != NULL);
+    }
+
+    /** Call all the functions in the chain in sequence
+     */
+    void call(ContextType context) {
+        ((const CallChainOfFunctionPointersWithContext*) this)->call(context);
+    }
+
+    /**
+     * @brief same as above but const 
+     */
+    void call(ContextType context) const {
+        currentCalled = chainHead;
+
+        while(currentCalled) { 
+            currentCalled->call(context);
+            // if this was the head and the call removed the head
+            if(currentCalled == NULL) { 
+                currentCalled = chainHead;
+            } else {
+                currentCalled = currentCalled->getNext();
+            }
+        }
+    }
+
+    /**
+     * @brief same as above but with function call operator
+     * \code
+     * 
+     * void first(bool);
+     * void second(bool);
+     * 
+     * CallChainOfFunctionPointerWithContext<bool> foo;
+     * 
+     * foo.attach(first);
+     * foo.attach(second);
+     * 
+     * // call the callchain like a function
+     * foo(true);
+     * 
+     * \endcode
+     */
+    void operator()(ContextType context) const {
+        call(context);
+    }
+
+    /**
+     * @brief bool conversion operation
+     */
+    bool toBool() const {
+        return chainHead != NULL;
+    }
+
+private:
+    pFunctionPointerWithContext_t common_add(pFunctionPointerWithContext_t pf) {
+        if (chainHead == NULL) {
+            chainHead = pf;
+        } else {
+            pf->chainAsNext(chainHead);
+            chainHead = pf;
+        }
+
+        return chainHead;
+    }
+
+private:
+    pFunctionPointerWithContext_t chainHead;
+    // iterator during a function call, this has to be mutable because the call function is const.
+    // Note: mutable is the correct behaviour here, the iterator never leak outside the object.
+    // So the object can still be seen as logically const even if it change its internal state
+    mutable pFunctionPointerWithContext_t currentCalled;
+
+
+    /* Disallow copy constructor and assignment operators. */
+private:
+    CallChainOfFunctionPointersWithContext(const CallChainOfFunctionPointersWithContext &);
+    CallChainOfFunctionPointersWithContext & operator = (const CallChainOfFunctionPointersWithContext &);
+};
+
+#endif
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