libobjc/objects.c

   1 /* GNU Objective C Runtime class related functions
   2    Copyright (C) 1993, 1995, 1996, 2009 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.h>
  35 # include <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 class_create_instance (Class class)
  71 {
  72   return class_createInstance (class, 0);
  73 }
  74
  75 /* Temporary, while we are including objc-api.h instead of runtime.h.  */
  76 #undef object_copy
  77
  78 id
  79 object_copy (id object, size_t extraBytes)
  80 {
  81   if ((object != nil) && CLS_ISCLASS (object->class_pointer))
  82     {
  83       /* TODO: How should it work with C++ constructors ? */
  84       id copy = class_createInstance (object->class_pointer, extraBytes);
  85       memcpy (copy, object, object->class_pointer->instance_size + extraBytes);
  86       return copy;
  87     }
  88   else
  89     return nil;
  90 }
  91
  92 id
  93 object_dispose (id object)
  94 {
  95   if ((object != nil) && CLS_ISCLASS (object->class_pointer))
  96     {
  97       /* TODO: Invoke C++ destructors on all appropriate C++ instance
  98          variables.  But what happens with the garbage collector ?
  99          Would object_dispose() be ever called in that case ?  */
 100
 101       objc_free (object);
 102     }
 103   return nil;
 104 }
 105
 106 const char *
 107 object_getClassName (id object)
 108 {
 109   if (object != nil)
 110     return object->class_pointer->name;
 111   else
 112     return "Nil";
 113 }
 114
 115 Class
 116 object_setClass (id object, Class class_)
 117 {
 118   if (object == nil)
 119     return Nil;
 120   else
 121     {
 122       Class old_class = object->class_pointer;
 123
 124       object->class_pointer = class_;
 125       return old_class;
 126     }
 127 }
 128
 129 /*
 130   Hook functions for memory allocation and disposal.  Deprecated
 131   and currently unused.
 132 */
 133
 134 id (*_objc_object_alloc) (Class)   = 0;
 135 id (*_objc_object_dispose) (id)    = 0;
 136 id (*_objc_object_copy) (id)       = 0;