[BCB] cocoa framework 의 retain 흉내내기

retainCount 매커니즘을 흉내내보았다.

객체할당시 4바이트를 추가로 할당하여 retainCount 영역으로 사용.

실사용은 해보지 않은 코드이므로 충분한 검증이 필요하다.

//---------------------------------------------------------------------------

#include <vcl.h>

#pragma hdrstop

#include "Unit1.h"

//---------------------------------------------------------------------------

#pragma package(smart_init)

#pragma resource "*.dfm"

TForm1 *Form1;

//---------------------------------------------------------------------------

#define DECLARE_RETAIN(CLASSNAME) \

private: \

    static size_t CLASSNAME ## __RETAINEDCLASS_CLASSSIZE__; \

    static unsigned int* __fastcall CLASSNAME ## __RETAINEDCLASS_RETAINCOUNTVARABLEPOINTER(void *rawMemory) { \

        return (CLASSNAME::CLASSNAME ## __RETAINEDCLASS_CLASSSIZE__ > 0? (unsigned int *)(((char*)rawMemory) + CLASSNAME::CLASSNAME ## __RETAINEDCLASS_CLASSSIZE__): 0); \

    } \

    unsigned int __fastcall CLASSNAME ## __GET_RETAIN_COUNT__(void) { \

        return *CLASSNAME::CLASSNAME ## __RETAINEDCLASS_RETAINCOUNTVARABLEPOINTER(this); \

    } \

public: \

    static void* operator new(size_t size) { \

        return ((CLASSNAME *)malloc((CLASSNAME::CLASSNAME ## __RETAINEDCLASS_CLASSSIZE__ = size) + sizeof(unsigned int)))->retain(); \

    } \

    static void operator delete(void *rawMemory) { \

        unsigned int *retainCount = CLASSNAME::CLASSNAME ## __RETAINEDCLASS_RETAINCOUNTVARABLEPOINTER(rawMemory); \

        if (*retainCount > 0 && !(--(*retainCount))) free(rawMemory); \

    } \

    __property unsigned int retainCount = {read = TRetainedClass__GET_RETAIN_COUNT__}; \

    CLASSNAME* __fastcall retain(void) { \

        (*CLASSNAME::CLASSNAME ## __RETAINEDCLASS_RETAINCOUNTVARABLEPOINTER(this))++; \

        return this; \

    }

#define USE_RETAIN(CLASSNAME) size_t CLASSNAME::CLASSNAME ## __RETAINEDCLASS_CLASSSIZE__ = 0;

#define PREVENT_DESTRUCTOR_MULTICALL if (retainCount != 1) return;

class TRetainedClass

{

    DECLARE_RETAIN(TRetainedClass);

public:

    __fastcall ~TRetainedClass(void)

    {   PREVENT_DESTRUCTOR_MULTICALL

        ShowMessage("dealloc");

    }

};

USE_RETAIN(TRetainedClass);

//---------------------------------------------------------------------------

__fastcall TForm1::TForm1(TComponent* Owner)

    : TForm(Owner)

{

    TRetainedClass *test = new TRetainedClass;

    ShowMessage(test->retainCount);

    test->retain();

    ShowMessage(test->retainCount);

    delete test;

    ShowMessage(test->retainCount);

    delete test;

}

//---------------------------------------------------------------------------