Re: [AD] errno killer patch (NICE!)

[Gareth Bushell <garth@xxxxxxxxxx>]

Eric Botcazou wrote:

> The attached patch removes all occurences of errno in the datedit/plugins
> code. It changes the prototype of the 'save' method of plugins to make it
> return a value.
>
> --
> Eric Botcazou
>  
Outstanding!!!

I was just incountering this problem while porting the allegro packfile 
to filters. (as discussed on alleg5 list)
I am at present creating a patch that makes the datafile routines 
unaware of the underlying packfile structure ( lot of f->todo references 
). This will enable the packfile routines to be ported over to filters 
without too much work! Look how tidy  pack_fopen becomes with filters 
underlying it. (actual working code) I'm hopeing pack_fopen_chunk will 
be as nice! I think so but I'm writing that tomorrow.

Garth

/* packfile emulation - How tidy is it with filters!?! :-) */
PACKFILE * pack_fopen (char *filename, const char *mode)
{
       struct filter *f;
       struct filter *parent;
      
       allegro check to see if file is ok
       if( !_al_file_isok(filename))
           return NULL;
      
       /* Sort out the parameters */
       if( strpbrk( mode, "wW" ) )
       {
               f = al_filter_file(filename,"w");   
               if( f == NULL )
               {
                       fprintf(stderr,"filename open(w) 
failed:%s",filename);
                       return NULL;
               }
       }
       else
       {
               /* Read mode then */
               f = al_filter_file(filename,"r");
               if( f == NULL )
               {
                       fprintf(stderr,"filename open(r) 
failed:%s",filename);
                       return NULL;
               }
       }
      
       parent = al_filter_buffer( f, 4096 );
       if( parent == NULL )
       {
               al_filter_close( f );
               return NULL;
       }

       /* doesn't matter if we lose refernce 'cause
        * filter_close will close all layers */
       f = parent;

#ifdef FILTER_PASSWORD
       if( password[0] )
       {
               /* How cool! Filters Rock */
               parent = filter_encrypt(f, ENCRYPT_METHOD_ALLEGV4_NEW, 
"password");
               if( parent == NULL )
               {
                       filter_close( f );
                       return NULL;
               }
               f = parent;
       }
#endif/*FILTER_PASSWORD*/

              
       /* Packfile ? */
       if( strpbrk(mode, "pP") )
       {
               /* Read file.c:pack_fopen fo figure out what to write in
                * The compression filter
                */
               struct filter *parent = al_filter_alcompress( f, 1 );
               if( parent == NULL )
               {
                       al_filter_close( f );
                       return NULL;
               }
          }

       /* compression support (not) */
       if( strpbrk(mode, "!") )
       {
               parent = al_filter_alcompress( f, 0 );
               if( parent == NULL )
               {
                       al_filter_close( f );
                       return NULL;
               }
               f = parent;
       }
      
       return f;
}