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 * Implementation of a cleanup stack for exception handling on platforms

 *  that don't clean up the stack automatically after an exception

 *  occurs. The macro's SAFEPUSH and SAFEPOP as defined in

 *  plat//lisptype.h define which cleanup handler

 *  to use, so it can be configured differently for different platforms.

 *

 */

#define __lispcleanupstack_h__

#include "grower.h"

 *  Only classes derived from this one can be pushed onto

 *  a cleanup stack. This in order to assure the cleanup code

 *  knows where to find the destructor.

 *

 *  Typical candidates for cleanup include places in the code that

 *  have temporal global side effects that need to be finalized on,

 *  Like opening a file for reading, reading and then closing. If

 *  reading prematurely finishes through an exception, the file

 *  should be closed.

 */

class LispBase : public YacasBase

{

public:

    virtual void Delete()=0;

    virtual ~LispBase(){};

};

 *  Use this clean up stack if the compiler generates

 *  cleanup code itself (particularly for newer c++ compilers).

 *  Alternatively SAFEPUSH and SAFEPOP can then be defined to do nothing.

 */

class LispCleanup : public YacasBase

{

public:

   inline LispCleanup() : iObjects() {}

    virtual ~LispCleanup();

    /// Push an object onto the cleanup stack for guarding

    virtual void Push(LispBase& aObject);

    /// Pop an object from the cleanup stack (the system is finished using it)

    virtual void Pop();

    /// Exception occurred: delete all objects on the stack, back to front.

    virtual void Delete();

    /** For testing purposes, verify that all places that pushed an object

     *  popped it too.

     */

    void CheckStackEmpty();

    CArrayGrower > iObjects;

};

 *  Use this clean up stack if the compiler doesn't generate

 *  cleanup code itself (particularly for older c++ compilers).

 */

class DeletingLispCleanup : public LispCleanup

{

public:

    virtual ~DeletingLispCleanup();

    virtual void Push(LispBase& aObject);

    virtual void Pop();

    virtual void Delete();

};