html_text_viewer.cpp

/* Date : 22 Mar 2017 - Wed */

struct ContentViewer_t;
struct ContentEngine_t;
struct RenderingEngine_t;

struct Callable_t
{
   virtual void callback() = 0;
};

struct ContentEngine_t : Callable_t
{
   Callable_t *cview, *reng;
   virtual void SaySomething() = 0;
   virtual void TalkWithREng() = 0;
   virtual void TalkWithCView() = 0;
   virtual void SetContentViewer(Callable_t *) = 0;
   virtual void SetRenderingEngine(Callable_t *) = 0;
};

struct HTMLContentEngine_t : ContentEngine_t
{
   /* function to talk to content
      engine from rendering engine  */
   void callback() { /* do something */ }

   void SetContentViewer(Callable_t *ptr) { cview=ptr; }
   void SetRenderingEngine(Callable_t *ptr) { reng=ptr; }

   void SaySomething() { /* do something */ }

   void TalkWithCView() { cview->callback(); }

   void TalkWithREng() { reng->callback(); }
};

struct TextContentEngine_t : ContentEngine_t
{
   /* function to talk to content
      engine from rendering engine  */
   void callback() { /* do something */ }

   void SetContentViewer(Callable_t *ptr) { cview=ptr; }
   void SetRenderingEngine(Callable_t *ptr) { reng=ptr; }

   void SaySomething() { /* do something */ }

   void TalkWithCView() { cview->callback(); }

   void TalkWithREng() { reng->callback(); }
};

struct RenderingEngine_t : Callable_t
{
   Callable_t *cview, *ceng;
   virtual void SaySomething() = 0;
   virtual void TalkWithCEng() = 0;
   virtual void TalkWithCView() = 0;
   virtual void SetContentEngine(Callable_t *) = 0;
   virtual void SetContentViewer(Callable_t *) = 0;
};

struct HTMLRenderingEngine_t : RenderingEngine_t
{

   /* Function to talk to redering
      engine from content engine    */
   void callback() { /* do something */ }

   void SetContentEngine(Callable_t *ptr) { ceng=ptr; }
   void SetContentViewer(Callable_t *ptr) { cview=ptr; }

   void SaySomething() { /* do something */ }

   void TalkWithCView() { cview->callback(); }

   void TalkWithCEng() { ceng->callback(); }
};

struct TextRenderingEngine_t : RenderingEngine_t
{

   /* Function to talk to redering
      engine from content engine    */
   void callback() { /* do something */ }

   void SetContentEngine(Callable_t *ptr) { ceng=ptr; }
   void SetContentViewer(Callable_t *ptr) { cview=ptr; }

   void SaySomething() { /* do something */ }

   void TalkWithCView() { cview->callback(); }

   void TalkWithCEng() { ceng->callback(); }
};

struct FileType
{
   enum Values { Html = 'h', Text = 't' };
};

typedef FileType::Values FileType_t;

struct ContentViewer_t : Callable_t
{
   ContentEngine_t *ceng;
   RenderingEngine_t *reng;

   void callback() { /* do something */ }

   ContentViewer_t(FileType_t fileType)
   {
      if(FileType::Html == fileType)
      {
         ceng = new HTMLContentEngine_t;
         reng = new HTMLRenderingEngine_t;
      }
      else if(FileType::Text == fileType)
      {
         ceng = new TextContentEngine_t;
         reng = new TextRenderingEngine_t;
      }

      ceng->SetRenderingEngine(reng);
      reng->SetContentEngine(ceng);
   }

   void TalkWithOthers()
   {
      ceng->SaySomething();
      reng->SaySomething();
   }

   ~ContentViewer_t()
   {
      delete ceng;
      delete reng;
   }
};

int main(int argc, char *argv[])
{
   ContentViewer_t cview(FileType_t(*argv));
   return 0;
}