mtsCallableReadMethod.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-    */
/* ex: set filetype=cpp softtabstop=4 shiftwidth=4 tabstop=4 cindent expandtab: */

/*

  Author(s): Anton Deguet
  Created on: 2010-09-16

  (C) Copyright 2010 Johns Hopkins University (JHU), All Rights
  Reserved.

--- begin cisst license - do not edit ---

This software is provided "as is" under an open source license, with
no warranty.  The complete license can be found in license.txt and
http://www.cisst.org/cisst/license.txt.

--- end cisst license ---
*/


#ifndef _mtsCallableReadMethod_h
#define _mtsCallableReadMethod_h


#include <cisstMultiTask/mtsCallableReadBase.h>
#include <cisstMultiTask/mtsGenericObjectProxy.h>

#include <string>


template <class _classType, class _resultType>
class mtsCallableReadMethod: public mtsCallableReadBase {

public:
    typedef mtsCallableReadBase BaseType;
    typedef _resultType ResultType;

    typedef _classType ClassType;

    typedef mtsCallableReadMethod<ClassType, ResultType> ThisType;

    typedef bool(_classType::*ActionType)(ResultType & argument) const;

private:
    inline mtsCallableReadMethod(const ThisType & CMN_UNUSED(other)) {}

protected:
    ActionType Action;

    ClassType * ClassInstantiation;

    template <bool, typename _dummy = void>
    class ConditionalCast {
        // Default case: ResultType not derived from mtsGenericObjectProxy
    public:
        static mtsExecutionResult CallMethod(ClassType * classInstantiation, ActionType action, mtsGenericObject & argument) {
            ResultType * argumentCasted = mtsGenericTypes<ResultType>::CastArg(argument);
            if (argumentCasted == 0) {
                return mtsExecutionResult::INVALID_INPUT_TYPE;
            }
            if ( (classInstantiation->*action)(*argumentCasted) ) {
                return mtsExecutionResult::COMMAND_SUCCEEDED;
            }
            return mtsExecutionResult::METHOD_OR_FUNCTION_FAILED;
        }
    };

    template <typename _dummy>
    class ConditionalCast<true, _dummy> {
        // Specialization: ResultType is derived from mtsGenericObjectProxy (and thus also from mtsGenericObject)
        // In this case, we may need to create a temporary Proxy object.
    public:
        static mtsExecutionResult CallMethod(ClassType * classInstantiation, ActionType action, mtsGenericObject & argument) {
            // First, check if a Proxy object was passed.
            ResultType * argumentCasted = dynamic_cast<ResultType *>(&argument);
            if (argumentCasted) {
                if ( (classInstantiation->*action)(*argumentCasted) ) {
                    return mtsExecutionResult::COMMAND_SUCCEEDED;
                }
                return mtsExecutionResult::METHOD_OR_FUNCTION_FAILED;
            }
            // If it isn't a Proxy, maybe it is a ProxyRef
            typedef typename ResultType::RefType ResultRefType;
            ResultRefType * dataRef = dynamic_cast<ResultRefType *>(&argument);
            if (!dataRef) {
                CMN_LOG_INIT_ERROR << "mtsCallableRead for " << typeid(ClassType).name()
                                   << ": CallMethod could not cast from " << typeid(argument).name()
                                   << " to " << typeid(ResultRefType).name() 
                           << ", arg type is " << argument.Services()->GetName() << std::endl;
                return mtsExecutionResult::INVALID_INPUT_TYPE;
            }
            // Now, make the call using the temporary
            ResultType temp;
            if ( (classInstantiation->*action)(temp) ) {
                // Finally, copy the data to the return
                *dataRef = temp;
                return mtsExecutionResult::COMMAND_SUCCEEDED;
            }
            // Copy result anyway
            *dataRef = temp;
            return mtsExecutionResult::METHOD_OR_FUNCTION_FAILED;
        }
    };

public:
    mtsCallableReadMethod(void): BaseType(), ClassInstantiation(0) {}

    mtsCallableReadMethod(ActionType action, ClassType * classInstantiation):
        BaseType(),
        Action(action),
        ClassInstantiation(classInstantiation)
    {}

    virtual ~mtsCallableReadMethod() {}

    /* documented in base class */
    mtsExecutionResult Execute(mtsGenericObject & argument) {
        return ConditionalCast<cmnIsDerivedFromTemplated<ResultType, mtsGenericObjectProxy>::IS_DERIVED>
            ::CallMethod(ClassInstantiation, Action, argument);
    }

    /* documented in base class */
    void ToStream(std::ostream & outputStream) const {
        if (this->ClassInstantiation) {
            outputStream << "method based callable void return object using class/object \""
                         << mtsObjectName(this->ClassInstantiation) << "\"";
        } else {
            outputStream << "invalid method based callable object";
        }
    }
};

template <class _classType>
class mtsCallableReadMethodGeneric: public mtsCallableReadBase {

public:
    typedef mtsCallableReadBase BaseType;

    typedef _classType ClassType;

    typedef mtsCallableReadMethodGeneric<ClassType> ThisType;

    typedef bool(_classType::*ActionType)(mtsGenericObject & result) const;

private:
    inline mtsCallableReadMethodGeneric(const ThisType & CMN_UNUSED(other)) {}

protected:
    ActionType Action;

    ClassType * ClassInstantiation;

public:
    mtsCallableReadMethodGeneric(void): BaseType(), ClassInstantiation(0) {}

    mtsCallableReadMethodGeneric(ActionType action, ClassType * classInstantiation):
        BaseType(),
        Action(action),
        ClassInstantiation(classInstantiation)
    {}

    virtual ~mtsCallableReadMethodGeneric() {}

    /* documented in base class */
    mtsExecutionResult Execute(mtsGenericObject & result) {
        if ((ClassInstantiation->*Action)(result) ) {
            return mtsExecutionResult::COMMAND_SUCCEEDED;
        }
        return mtsExecutionResult::METHOD_OR_FUNCTION_FAILED;
    }

    /* documented in base class */
    void ToStream(std::ostream & outputStream) const {
        if (this->ClassInstantiation) {
            outputStream << "method based callable read object using class/object \""
                         << mtsObjectName(this->ClassInstantiation) << "\"";
        } else {
            outputStream << "invalid method based callable object";
        }
    }
};

#endif // _mtsCallableReadMethod_h