mtsTaskFromCallback.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):  Peter Kazanzides
  Created on: 2008-09-10

  (C) Copyright 2008-2012 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 _mtsTaskFromCallback_h
#define _mtsTaskFromCallback_h

#include <cisstCommon/cmnPortability.h>
#include <cisstMultiTask/mtsTask.h>

// Always include last
#include <cisstMultiTask/mtsExport.h>

#ifndef MTS_TASK_CALLBACK_CONVENTION
#define MTS_TASK_CALLBACK_CONVENTION
#endif

class CISST_EXPORT mtsTaskFromCallback : public mtsTask
{
    CMN_DECLARE_SERVICES(CMN_NO_DYNAMIC_CREATION, CMN_LOG_ALLOW_DEFAULT);

protected:
    typedef mtsTask BaseType;

    /************************ Protected task data  *********************/
    bool inRunInternal;

    /********************* Methods that call user methods *****************/

    void *RunInternal(void* argument);

    void StartupInternal(void);

public:
    /********************* Task constructor and destructor *****************/

    mtsTaskFromCallback(const std::string & name,
                        unsigned int sizeStateTable = 256):
        mtsTask(name, sizeStateTable), inRunInternal(false) {}

    virtual ~mtsTaskFromCallback() {}

    /********************* Methods to change task status *****************/
    /* (use Kill method from base class)                                 */

    /* Create a new thread (if needed). */
    void Create(void *data = 0);

    void Start(void);

    void Suspend(void);

    void Kill(void);

    virtual void *DoCallback(void *data = 0) {
        // The user Run() method should call SetThreadReturnValue.
        return RunInternal(data);
    }
};

CMN_DECLARE_SERVICES_INSTANTIATION(mtsTaskFromCallback)


// PK: This class should be in a separate file, but I would like to
//     find a better name first.

class CISST_EXPORT mtsTaskFromCallbackAdapter : public mtsTaskFromCallback
{
    CMN_DECLARE_SERVICES(CMN_NO_DYNAMIC_CREATION, CMN_LOG_ALLOW_DEFAULT);

protected:
    typedef mtsTaskFromCallback BaseType;

    enum SignatureType {INVALID = 0, VALID = 0x3242 };
    struct CallbackData {
        SignatureType signature;
        mtsTaskFromCallback* obj;
        CallbackData() : signature(INVALID), obj(0) {}
        ~CallbackData() {}
    };
    CallbackData callbackData;

public:

    mtsTaskFromCallbackAdapter(const std::string & name,
                               unsigned int sizeStateTable = 256) :
      mtsTaskFromCallback(name, sizeStateTable),
      callbackData() { }

    ~mtsTaskFromCallbackAdapter() {}

    template <class _callbackReturnType>
    static _callbackReturnType MTS_TASK_CALLBACK_CONVENTION CallbackAdapter(void *obj);

    virtual void *GetCallbackParameter() {
        callbackData.signature = VALID;
        callbackData.obj = this;
        return static_cast<void*>(&callbackData);
    }

};

CMN_DECLARE_SERVICES_INSTANTIATION(mtsTaskFromCallbackAdapter)

template <class _callbackReturnType>
_callbackReturnType MTS_TASK_CALLBACK_CONVENTION mtsTaskFromCallbackAdapter::CallbackAdapter(void *obj)
{
    if (!obj) {
        CMN_LOG_INIT_ERROR << "CallbackAdapter got null pointer" << std::endl;
        return _callbackReturnType();
    }
    CallbackData* _this = static_cast<CallbackData*>(obj);
    if (_this->signature != VALID) {
        CMN_LOG_INIT_ERROR << "CallbackAdapter received invalid signature: " << _this->signature << std::endl;
        return _callbackReturnType();
    }
    void *ret =_this->obj->DoCallback(0);
    // Following won't compile if _callbackReturnType is 'void'.
    // TBD:  workaround using a type traits approach.
    return *static_cast<_callbackReturnType *>(ret);
}


#endif // _mtsTaskFromCallback_h