StudyGuts.h

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#ifndef SimTK_SimTKCOMMON_STUDY_GUTS_H_
#define SimTK_SimTKCOMMON_STUDY_GUTS_H_

/* -------------------------------------------------------------------------- *
 *                      SimTK Core: SimTKcommon                               *
 * -------------------------------------------------------------------------- *
 * This is part of the SimTK Core biosimulation toolkit originating from      *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org.               *
 *                                                                            *
 * Portions copyright (c) 2007 Stanford University and the Authors.           *
 * Authors: Michael Sherman                                                   *
 * Contributors:                                                              *
 *                                                                            *
 * Permission is hereby granted, free of charge, to any person obtaining a    *
 * copy of this software and associated documentation files (the "Software"), *
 * to deal in the Software without restriction, including without limitation  *
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,   *
 * and/or sell copies of the Software, and to permit persons to whom the      *
 * Software is furnished to do so, subject to the following conditions:       *
 *                                                                            *
 * The above copyright notice and this permission notice shall be included in *
 * all copies or substantial portions of the Software.                        *
 *                                                                            *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,   *
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL    *
 * THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,    *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR      *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE  *
 * USE OR OTHER DEALINGS IN THE SOFTWARE.                                     *
 * -------------------------------------------------------------------------- */

#include "SimTKcommon/basics.h"
#include "SimTKcommon/Simmatrix.h"
#include "SimTKcommon/internal/State.h"

namespace SimTK {

// See below for definitions.
static void systemDestructImplLocator(Study::Guts*);
static Study::Guts* systemCloneImplLocator(const Study::Guts&);

// TODO: more to come.

class SimTK_SimTKCOMMON_EXPORT Study::Guts {
    class GutsRep;
    friend class GutsRep;

    // This is the only data member in this class.
    GutsRep* rep; // opaque implementation of Study::Guts base class.
public:
    // Constructor must be inline for binary compatibility. Note that this
    // serves as a default constructor since both arguments have defaults.
    inline explicit Guts(const String& name="<UNNAMED STUDY>", 
                         const String& version="0.0.0");

    // This won't be called directly from library-side code. Instead,
    // a method from the explicit virtual function table will be invoked
    // which will know where to find this on in the C++ VFT on the client side.
    virtual ~Guts() {librarySideDestruction();}

    const String& getName()    const;
    const String& getVersion() const;

    // Obtain the owner handle for this Study::Guts object.
    const Study& getStudy() const;
    Study& updStudy();

    void setOwnerHandle(Study&);
    bool hasOwnerHandle() const;

    explicit Guts(class GutsRep* r) : rep(r) { }
    bool           hasRep() const {return rep!=0;}
    const GutsRep& getRep() const {assert(rep); return *rep;}
    GutsRep&       updRep() const {assert(rep); return *rep;}

    // Call this routine to invoke the client-side virtual destructor,
    // by going through the library-side explicit virtual function table.
    static void destruct(Study::Guts*);

    // Wrap the cloneImpl virtual method.
    Study::Guts* clone() const;

protected:
    Guts(const Guts&);  // copies the base class; for use from derived class copy constructors
    
    // The destructor is already virtual; see above.

    virtual Study::Guts* cloneImpl() const = 0;

private:
    Guts& operator=(const Guts&); // suppress default copy assignment operator

    // These typedefs are used internally to manage the binary-compatible
    // handling of the virtual function table.

    // This first entry calls the virtual destructor above to delete the
    // heap-allocated object pointed to by the passed-in pointer.
    typedef void (*DestructImplLocator)(Study::Guts*);
    typedef Study::Guts* (*CloneImplLocator)(const Study::Guts&);

    void librarySideConstruction(const String& name, const String& version);
    void librarySideDestruction();

    void registerDestructImpl(DestructImplLocator);
    void registerCloneImpl(CloneImplLocator);

    // We want the locator functions to have access to the protected "Impl"
    // virtual methods, so we make them friends.

    friend void systemDestructImplLocator(Study::Guts*);
    friend Study::Guts* systemCloneImplLocator(const Study::Guts&);
};


// These are used to supply the client-side virtual function to the library, without
// the client and library having to agree on the layout of the virtual function tables.

static void systemDestructImplLocator(Study::Guts* sysp)
  { delete sysp; } // invokes virtual destructor
static Study::Guts* systemCloneImplLocator(const Study::Guts& sys)
  { return sys.cloneImpl(); }

// Constructor must be inline so that it has access to the above static
// functions which are private to the client-side compilation unit in which the
// client-side virtual function table is understood.
inline Study::Guts::Guts(const String& name, const String& version) : rep(0)
{
    librarySideConstruction(name, version);

    // Teach the library code how to call client side virtual functions by
    // calling through the client side compilation unit's private static
    // locator functions.
    registerDestructImpl(systemDestructImplLocator);
    registerCloneImpl(systemCloneImplLocator);
}

} // namespace SimTK

#endif // SimTK_SimTKCOMMON_STUDY_GUTS_H_