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      1 /* GNU Objective C Runtime class related functions
      2    Copyright (C) 1993-2022 Free Software Foundation, Inc.
      3    Contributed by Kresten Krab Thorup
      4 
      5 This file is part of GCC.
      6 
      7 GCC is free software; you can redistribute it and/or modify it under the
      8 terms of the GNU General Public License as published by the Free Software
      9 Foundation; either version 3, or (at your option) any later version.
     10 
     11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
     12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
     13 FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
     14 details.
     15 
     16 Under Section 7 of GPL version 3, you are granted additional
     17 permissions described in the GCC Runtime Library Exception, version
     18 3.1, as published by the Free Software Foundation.
     19 
     20 You should have received a copy of the GNU General Public License and
     21 a copy of the GCC Runtime Library Exception along with this program;
     22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     23 <http://www.gnu.org/licenses/>.  */
     24 
     25 #include "objc-private/common.h"
     26 #include "objc/runtime.h"
     27 #include "objc/thr.h"                   /* Required by objc-private/runtime.h.  */
     28 #include "objc-private/module-abi-8.h"  /* For CLS_ISCLASS and similar.  */
     29 #include "objc-private/runtime.h"	/* the kitchen sink */
     30 
     31 #include <string.h>                     /* For memcpy()  */
     32 
     33 #if OBJC_WITH_GC
     34 # include <gc/gc.h>
     35 # include <gc/gc_typed.h>
     36 #endif
     37 
     38 /* FIXME: The semantics of extraBytes are not really clear.  */
     39 id
     40 class_createInstance (Class class, size_t extraBytes)
     41 {
     42   id new = nil;
     43 
     44 #if OBJC_WITH_GC
     45   if (CLS_ISCLASS (class))
     46     new = (id) GC_malloc_explicitly_typed (class->instance_size + extraBytes,
     47 					   (GC_descr)class->gc_object_type);
     48 #else
     49   if (CLS_ISCLASS (class))
     50     new = (id) objc_calloc (class->instance_size + extraBytes, 1);
     51 #endif
     52 
     53   if (new != nil)
     54     {
     55       /* There is no need to zero the memory, since both
     56 	 GC_malloc_explicitly_typed and objc_calloc return zeroed
     57 	 memory.  */
     58       new->class_pointer = class;
     59     }
     60 
     61   /* TODO: Invoke C++ constructors on all appropriate C++ instance
     62      variables of the new object.  */
     63 
     64   return new;
     65 }
     66 
     67 /* Traditional GNU Objective-C Runtime API.  */
     68 id
     69 object_copy (id object, size_t extraBytes)
     70 {
     71   if ((object != nil) && CLS_ISCLASS (object->class_pointer))
     72     {
     73       /* TODO: How should it work with C++ constructors ? */
     74       id copy = class_createInstance (object->class_pointer, extraBytes);
     75       memcpy (copy, object, object->class_pointer->instance_size + extraBytes);
     76       return copy;
     77     }
     78   else
     79     return nil;
     80 }
     81 
     82 id
     83 object_dispose (id object)
     84 {
     85   if ((object != nil) && CLS_ISCLASS (object->class_pointer))
     86     {
     87       /* TODO: Invoke C++ destructors on all appropriate C++ instance
     88 	 variables.  But what happens with the garbage collector ?
     89 	 Would object_dispose() be ever called in that case ?  */
     90 
     91       objc_free (object);
     92     }
     93   return nil;
     94 }
     95 
     96 const char *
     97 object_getClassName (id object)
     98 {
     99   if (object != nil)
    100     return object->class_pointer->name;
    101   else
    102     return "Nil";
    103 }
    104 
    105 Class
    106 object_setClass (id object, Class class_)
    107 {
    108   if (object == nil)
    109     return Nil;
    110   else
    111     {
    112       Class old_class = object->class_pointer;
    113 
    114       object->class_pointer = class_;
    115       return old_class;
    116     }
    117 }
    118