libobjc/objects.c

   1 /* GNU Objective C Runtime class related functions
   2    Copyright (C) 1993-2018 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 inline
  40 id
  41 class_createInstance (Class class, size_t extraBytes)
  42 {
  43   id new = nil;
  44
  45 #if OBJC_WITH_GC
  46   if (CLS_ISCLASS (class))
  47     new = (id) GC_malloc_explicitly_typed (class->instance_size + extraBytes,
  48                                            (GC_descr)class->gc_object_type);
  49 #else
  50   if (CLS_ISCLASS (class))
  51     new = (id) objc_calloc (class->instance_size + extraBytes, 1);
  52 #endif
  53
  54   if (new != nil)
  55     {
  56       /* There is no need to zero the memory, since both
  57          GC_malloc_explicitly_typed and objc_calloc return zeroed
  58          memory.  */
  59       new->class_pointer = class;
  60     }
  61
  62   /* TODO: Invoke C++ constructors on all appropriate C++ instance
  63      variables of the new object.  */
  64
  65   return new;
  66 }
  67
  68 /* Traditional GNU Objective-C Runtime API.  */
  69 id
  70 object_copy (id object, size_t extraBytes)
  71 {
  72   if ((object != nil) && CLS_ISCLASS (object->class_pointer))
  73     {
  74       /* TODO: How should it work with C++ constructors ? */
  75       id copy = class_createInstance (object->class_pointer, extraBytes);
  76       memcpy (copy, object, object->class_pointer->instance_size + extraBytes);
  77       return copy;
  78     }
  79   else
  80     return nil;
  81 }
  82
  83 id
  84 object_dispose (id object)
  85 {
  86   if ((object != nil) && CLS_ISCLASS (object->class_pointer))
  87     {
  88       /* TODO: Invoke C++ destructors on all appropriate C++ instance
  89          variables.  But what happens with the garbage collector ?
  90          Would object_dispose() be ever called in that case ?  */
  91
  92       objc_free (object);
  93     }
  94   return nil;
  95 }
  96
  97 const char *
  98 object_getClassName (id object)
  99 {
 100   if (object != nil)
 101     return object->class_pointer->name;
 102   else
 103     return "Nil";
 104 }
 105
 106 Class
 107 object_setClass (id object, Class class_)
 108 {
 109   if (object == nil)
 110     return Nil;
 111   else
 112     {
 113       Class old_class = object->class_pointer;
 114
 115       object->class_pointer = class_;
 116       return old_class;
 117     }
 118 }