Generalized getAxisParam

src/sinqAxis.cpp

@@ -10,6 +10,8 @@
 #include <math.h>
 #include <unistd.h>
 
+#define getControllerMethod pController
+
 struct sinqAxisImpl {
     // Internal variables used in the movement timeout watchdog
     time_t expectedArrivalTime;
@@ -28,21 +30,23 @@ struct sinqAxisImpl {
     epicsTimeStamp lastPollTime;
 };
 
+template <typename T> struct TypeTag {};
+
 // Generic fallback - if the compiler tries to compile this function, it fails.
-template <typename T>
-asynStatus setAxisParam(sinqAxis *axis, const char *indexName,
-                        int (sinqController::*func)(), T writeValue,
-                        const char *callerFunctionName, int lineNumber) {
-    static_assert(
-        sizeof(T) == 0,
-        "no specialization of setAxisParam exists for the given type");
+template <typename A, typename C, typename T>
+asynStatus setAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), T writeValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<void>) {
+    static_assert(sizeof(T) == 0, "Unsupported type for setAxisParamImpl");
     return asynError;
 }
 
-template <>
-asynStatus setAxisParam<int>(sinqAxis *axis, const char *indexName,
-                             int (sinqController::*func)(), int writeValue,
-                             const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C>
+asynStatus setAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), int writeValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<int>) {
     int indexValue = (axis->pController()->*func)();
     asynStatus status = axis->setIntegerParam(indexValue, writeValue);
     if (status != asynSuccess) {
@@ -52,19 +56,21 @@ asynStatus setAxisParam<int>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
-template <>
-asynStatus setAxisParam<bool>(sinqAxis *axis, const char *indexName,
-                              int (sinqController::*func)(), bool writeValue,
-                              const char *callerFunctionName, int lineNumber) {
-    return setAxisParam(axis, indexName, func, static_cast<int>(writeValue),
-                        callerFunctionName, lineNumber);
+template <typename A, typename C>
+asynStatus setAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), bool writeValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<bool>) {
+    return setAxisParamImpl(axis, controller, indexName, func,
+                            static_cast<int>(writeValue), callerFunctionName,
+                            lineNumber, TypeTag<int>{});
 }
 
-template <>
-asynStatus
-setAxisParam<double>(sinqAxis *axis, const char *indexName,
-                     int (sinqController::*func)(), double writeValue,
-                     const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C>
+asynStatus setAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (sinqController::*func)(), double writeValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<double>) {
     int indexValue = (axis->pController()->*func)();
     asynStatus status = axis->setDoubleParam(indexValue, writeValue);
     if (status != asynSuccess) {
@@ -74,11 +80,11 @@ setAxisParam<double>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
-template <>
-asynStatus setAxisParam<char *>(sinqAxis *axis, const char *indexName,
-                                int (sinqController::*func)(), char *writeValue,
-                                const char *callerFunctionName,
-                                int lineNumber) {
+template <typename A, typename C>
+asynStatus setAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), char *writeValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<char *>) {
     int indexValue = (axis->pController()->*func)();
     asynStatus status = axis->setStringParam(indexValue, writeValue);
     if (status != asynSuccess) {
@@ -88,12 +94,11 @@ asynStatus setAxisParam<char *>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
-template <>
-asynStatus setAxisParam<const char *>(sinqAxis *axis, const char *indexName,
-                                      int (sinqController::*func)(),
-                                      const char *writeValue,
-                                      const char *callerFunctionName,
-                                      int lineNumber) {
+template <typename A, typename C>
+asynStatus setAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), const char *writeValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<const char *>) {
     int indexValue = (axis->pController()->*func)();
     asynStatus status = axis->setStringParam(indexValue, writeValue);
     if (status != asynSuccess) {
@@ -103,21 +108,31 @@ asynStatus setAxisParam<const char *>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
+template <typename A, typename C, typename T>
+asynStatus setAxisParam(A *axis, C *controller, const char *indexName,
+                        int (C::*func)(), T writeValue,
+                        const char *callerFunctionName, int lineNumber) {
+    return setAxisParamImpl(axis, controller, indexName, func, writeValue,
+                            callerFunctionName, lineNumber, TypeTag<T>{});
+}
+
 // Generic fallback - if the compiler tries to compile this function, it fails.
-template <typename T>
-asynStatus getAxisParam(sinqAxis *axis, const char *indexName,
-                        int (sinqController::*func)(), T *readValue,
-                        const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C, typename T>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), T *readValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<void>) {
     static_assert(
         sizeof(T) == 0,
         "no specialization of getAxisParam exists for the given type");
     return asynError;
 }
 
-template <>
-asynStatus getAxisParam<int>(sinqAxis *axis, const char *indexName,
-                             int (sinqController::*func)(), int *readValue,
-                             const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), int *readValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<int>) {
     int indexValue = (axis->pController()->*func)();
     asynStatus status = axis->pController()->getIntegerParam(
         axis->axisNo(), indexValue, readValue);
@@ -128,19 +143,20 @@ asynStatus getAxisParam<int>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
-template <>
-asynStatus getAxisParam<bool>(sinqAxis *axis, const char *indexName,
-                              int (sinqController::*func)(), bool *readValue,
-                              const char *callerFunctionName, int lineNumber) {
-    return getAxisParam(axis, indexName, func, (int *)readValue,
-                        callerFunctionName, lineNumber);
+template <typename A, typename C>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), bool *readValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<bool>) {
+    return getAxisParamImpl(axis, indexName, func, (int *)readValue,
+                            callerFunctionName, lineNumber);
 }
 
-template <>
-asynStatus
-getAxisParam<double>(sinqAxis *axis, const char *indexName,
-                     int (sinqController::*func)(), double *readValue,
-                     const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), double *readValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<double>) {
     int indexValue = (axis->pController()->*func)();
     asynStatus status = axis->pController()->getDoubleParam(
         axis->axisNo(), indexValue, readValue);
@@ -151,10 +167,11 @@ getAxisParam<double>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
-template <>
-asynStatus getAxisParam<char>(sinqAxis *axis, const char *indexName,
-                              int (sinqController::*func)(), char *readValue,
-                              const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), char *readValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<char>) {
 
     int maxChars = 200;
 
@@ -168,21 +185,22 @@ asynStatus getAxisParam<char>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
-template <size_t N>
-asynStatus getAxisParam(sinqAxis *axis, const char *indexName,
-                        int (sinqController::*func)(), char (&readValue)[N],
-                        const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C, size_t N>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), char (&readValue)[N],
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<char>) {
     // Decay the array to char*
-    return getAxisParam<char>(axis, indexName, func,
-                              static_cast<char *>(readValue),
-                              callerFunctionName, lineNumber);
+    return getAxisParamImpl(axis, controller, indexName, func,
+                            static_cast<char *>(readValue), callerFunctionName,
+                            lineNumber);
 }
 
-template <>
-asynStatus
-getAxisParam<std::string>(sinqAxis *axis, const char *indexName,
-                          int (sinqController::*func)(), std::string *readValue,
-                          const char *callerFunctionName, int lineNumber) {
+template <typename A, typename C>
+asynStatus getAxisParamImpl(A *axis, C *controller, const char *indexName,
+                            int (C::*func)(), std::string *readValue,
+                            const char *callerFunctionName, int lineNumber,
+                            TypeTag<std::string>) {
     int indexValue = (axis->pController()->*func)();
 
     // Convert the pointer to a reference, since getStringParam expects the
@@ -198,6 +216,14 @@ getAxisParam<std::string>(sinqAxis *axis, const char *indexName,
     return asynSuccess;
 }
 
+template <typename A, typename C, typename T>
+asynStatus getAxisParam(A *axis, C *controller, const char *indexName,
+                        int (C::*func)(), std::string *readValue,
+                        const char *callerFunctionName, int lineNumber) {
+    return getAxisParamImpl(axis, controller, indexName, func, readValue,
+                            callerFunctionName, lineNumber, TypeTag<T>{});
+}
+
 // =============================================================================
 
 sinqAxis::sinqAxis(class sinqController *pC, int axisNo)

src/sinqAxis.h

@@ -365,9 +365,22 @@ class epicsShareClass sinqAxis : public asynMotorAxis {
     asynStatus assertConnected();
 
     /**
-     * @brief Return a pointer to the axis controller
+     * @brief Return a pointer to the axis controller.
+     *
+     * This function should be overriden in derived classes using the `override`
+     * keyword so the macros `getAxisParamChecked` and `setAxisParamChecked`
+     * work correctly:
+     *
+     * ```
+     * class mySpecialAxis : public sinqAxis {
+        public:
+            mySpecialController* getControllerMethod() override {
+                return mySpecialControllerPtr;
+            }
+        };
+     * ```
      */
-    sinqController *pController() { return pC_; };
+    virtual sinqController *pController() { return pC_; };
 
     /**
      * @brief Returns true, if the axis was moving in the last poll cycle, and
@@ -423,9 +436,9 @@ class epicsShareClass sinqAxis : public asynMotorAxis {
  * @param lineNumber
  * @return asynStatus
  */
-template <typename T>
-asynStatus setAxisParam(sinqAxis *axis, const char *indexName,
-                        int (sinqController::*func)(), T writeValue,
+template <typename A, typename C, typename T>
+asynStatus setAxisParam(A *axis, C *controller, const char *indexName,
+                        int (C::*func)(), T writeValue,
                         const char *callerFunctionName, int lineNumber);
 
 /**
@@ -457,7 +470,7 @@ asynStatus setAxisParam(sinqAxis *axis, const char *indexName,
 #define setAxisParamChecked(axis, indexGetterFunction, writeValue)             \
     {                                                                          \
         asynStatus setStatus = setAxisParam(                                   \
-            axis, #indexGetterFunction,                                        \
+            axis, axis->pController(), #indexGetterFunction,                   \
             &std::remove_pointer<                                              \
                 decltype(axis->pController())>::type::indexGetterFunction,     \
             writeValue, __PRETTY_FUNCTION__, __LINE__);                        \
@@ -488,9 +501,9 @@ asynStatus setAxisParam(sinqAxis *axis, const char *indexName,
  * to.
  * @return asynStatus
  */
-template <typename T>
-asynStatus getAxisParam(sinqAxis *axis, const char *indexName,
-                        int (sinqController::*func)(), T *readValue,
+template <typename A, typename C, typename T>
+asynStatus getAxisParam(A *axis, C *controller, const char *indexName,
+                        int (C::*func)(), T *readValue,
                         const char *callerFunctionName, int lineNumber);
 
 /**
@@ -498,7 +511,7 @@ asynStatus getAxisParam(sinqAxis *axis, const char *indexName,
  *
  * This macro is a wrapper around `getIntegerParam` / `getDoubleParam` /
  * `getStringParam` which checks if the operation was successfull. If it wasn't,
- * it returns by calling the paramLibAccessFailed function.
+ * it returns by calling the paramLibAccessFailed function. In order
  *
  * For example, the following input:
  * ```
@@ -522,7 +535,7 @@ asynStatus getAxisParam(sinqAxis *axis, const char *indexName,
 #define getAxisParamChecked(axis, indexGetterFunction, readValue)              \
     {                                                                          \
         asynStatus getStatus = getAxisParam(                                   \
-            axis, #indexGetterFunction,                                        \
+            axis, axis->pController(), #indexGetterFunction,                   \
             &std::remove_pointer<                                              \
                 decltype(axis->pController())>::type::indexGetterFunction,     \
             readValue, __PRETTY_FUNCTION__, __LINE__);                         \