rom/oop/getmethod.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Get a pointer to a method for an object
   6     Lang: english
   7 */
   8 #include <exec/lists.h>
   9 #include <proto/exec.h>
  10 #include <oop/oop.h>
  11 #include <aros/debug.h>
  12 #include "intern.h"
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17 #include <proto/oop.h>
  18
  19         AROS_LH2(VOID *, OOP_GetMethod,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(OOP_Object  *, obj,    A0),
  23         AROS_LHA(OOP_MethodID,  mid,    D0),
  24
  25 /*  LOCATION */
  26         struct Library *, OOPBase, 21, OOP)
  27
  28 /*  FUNCTION
  29         Get a specific method function for a specific object and
  30         a specific interface. This a direct pointer to the method implementation.
  31         The pointer should ONLY be used on the object you aquired.
  32
  33     INPUTS
  34         obj     - pointer to object to get method for.
  35         mid     - method id for method to get. This may be obtained with GetMethodID()
  36
  37     RESULT
  38         The method asked for, or NULL if the method does not exist in
  39         the object's class.
  40
  41     NOTES
  42         !!! Use with EXTREME CAUTION. Very few programs need the extra speed gained
  43             by calling a method directly
  44         !!!
  45
  46     EXAMPLE
  47
  48     BUGS
  49         It returns VOID *. I got compiler errors when returning
  50         IPTR (*)(Class *, Object *, Msg)
  51
  52     SEE ALSO
  53         OOP_GetMethodID()
  54
  55     INTERNALS
  56
  57     HISTORY
  58         29-10-95    digulla automatically created from
  59                             intuition_lib.fd and clib/intuition_protos.h
  60
  61 *****************************************************************************/
  62 {
  63     AROS_LIBFUNC_INIT
  64
  65     struct IFMethod *ifm;
  66
  67     /* First get mid */
  68     /* Get the method from the object's class */
  69     ifm = meta_findmethod((OOP_Object *)OOP_OCLASS(obj), mid, (struct Library *)OOPBase);
  70     if (NULL == ifm)
  71         return NULL;
  72
  73     /* Paranoia */
  74     if (NULL == ifm->MethodFunc) {
  75         D(bug("!!! OOP/GetMethod(): IFMethod instance had no methodfunc. This should NEVER happen !!!\n"));
  76         return NULL;
  77     }
  78
  79     return (VOID *)ifm->MethodFunc;
  80
  81     AROS_LIBFUNC_EXIT
  82 } /* OOP_GetMethod */