libobjc/ivars.c

   1 /* GNU Objective C Runtime ivar related functions.
   2    Copyright (C) 2010 Free Software Foundation, Inc.
   3    Contributed by Nicola Pero
   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-private/module-abi-8.h" /* For runtime structures  */
  28 #include "objc/thr.h"
  29 #include "objc-private/runtime.h"      /* the kitchen sink */
  30 #include <string.h>                    /* For strcmp */
  31
  32 struct objc_ivar *
  33 class_getInstanceVariable (Class class_, const char *name)
  34 {
  35   if (class_ != Nil  &&  name != NULL)
  36     {
  37       objc_mutex_lock (__objc_runtime_mutex);
  38       while (class_ != Nil)
  39         {
  40           struct objc_ivar_list *ivars = class_->ivars;
  41           if (ivars != NULL)
  42             {
  43               int i;
  44
  45               for (i = 0; i < ivars->ivar_count; i++)
  46                 {
  47                   struct objc_ivar *ivar = &(ivars->ivar_list[i]);
  48
  49                   if (!strcmp (ivar->ivar_name, name))
  50                     {
  51                       objc_mutex_unlock (__objc_runtime_mutex);
  52                       return ivar;
  53                     }
  54                 }
  55             }
  56           class_ = class_->super_class;
  57         }
  58       objc_mutex_unlock (__objc_runtime_mutex);
  59     }
  60   return NULL;
  61 }
  62
  63 struct objc_ivar *
  64 class_getClassVariable (Class class_, const char *name)
  65 {
  66   if (class_ == Nil)
  67     return NULL;
  68
  69   /* Logically, since a class is an instance of its meta-class, and
  70      since its class methods are the instance methods of the
  71      meta-class, class variables should be instance variables of the
  72      meta-class.  That is different from the normal use of having
  73      'static' variables in the class implementation file, because
  74      every class would have its own variables.
  75
  76      Anyway, it is all speculative at this stage, but if we get class
  77      variables in Objective-C, it is conceivable that this
  78      implementation should work.  */
  79   return class_getInstanceVariable (class_->class_pointer, name);
  80 }
  81
  82 void *
  83 object_getIndexedIvars (id object)
  84 {
  85   if (object == nil)
  86     return NULL;
  87   else
  88     {
  89       return (void *)(((char *)object)
  90                       + object->class_pointer->instance_size);
  91     }
  92 }
  93
  94 struct objc_ivar *
  95 object_getInstanceVariable (id object, const char *name, void **returnValue)
  96 {
  97   if (object == nil  ||  name == NULL)
  98     return NULL;
  99   else
 100     {
 101       struct objc_ivar * variable = class_getInstanceVariable (object->class_pointer, name);
 102
 103       if (variable != NULL  &&  returnValue != NULL)
 104         {
 105           char *location = (char *)object + variable->ivar_offset;
 106
 107           *returnValue = *((id *)location);
 108         }
 109
 110       return variable;
 111     }
 112 }
 113
 114 struct objc_ivar *
 115 object_setInstanceVariable (id object, const char *name, void *newValue)
 116 {
 117   if (object == nil  ||  name == NULL)
 118     return NULL;
 119   else
 120     {
 121       struct objc_ivar * variable = class_getInstanceVariable (object->class_pointer, name);
 122
 123       if (variable != NULL)
 124         {
 125           char *location = (char *)object + variable->ivar_offset;
 126
 127           *((id *)location) = (id)newValue;
 128         }
 129
 130       return variable;
 131     }
 132 }
 133
 134 id object_getIvar (id object, struct objc_ivar * variable)
 135 {
 136   if (object == nil  ||  variable == NULL)
 137     return nil;
 138   else
 139     {
 140       char *location = (char *)object + variable->ivar_offset;
 141
 142       return *((id *)location);
 143     }
 144 }
 145
 146 void object_setIvar (id object, struct objc_ivar * variable, id value)
 147 {
 148   if (object == nil  ||  variable == NULL)
 149     return;
 150   else
 151     {
 152       char *location = (char *)object + variable->ivar_offset;
 153
 154       *((id *)location) = value;
 155     }
 156 }
 157
 158 const char * ivar_getName (struct objc_ivar * variable)
 159 {
 160   if (variable == NULL)
 161     return NULL;
 162
 163   return variable->ivar_name;
 164 }
 165
 166 ptrdiff_t ivar_getOffset (struct objc_ivar * variable)
 167 {
 168   if (variable == NULL)
 169     return 0;
 170
 171   return (ptrdiff_t)(variable->ivar_offset);
 172 }
 173
 174 const char * ivar_getTypeEncoding (struct objc_ivar * variable)
 175 {
 176   if (variable == NULL)
 177     return NULL;
 178
 179   return variable->ivar_type;
 180 }
 181
 182 struct objc_ivar ** class_copyIvarList (Class class_, unsigned int *numberOfReturnedIvars)
 183 {
 184   unsigned int count = 0;
 185   struct objc_ivar **returnValue = NULL;
 186   struct objc_ivar_list* ivar_list;
 187
 188   if (class_ == Nil)
 189     {
 190       if (numberOfReturnedIvars)
 191         *numberOfReturnedIvars = 0;
 192       return NULL;
 193     }
 194
 195   /* TODO: We do not need to lock the runtime mutex if the class has
 196      been registered with the runtime, since the instance variable
 197      list can not change after the class is registered.  The only case
 198      where the lock may be useful if the class is still being created
 199      using objc_allocateClassPair(), but has not been registered using
 200      objc_registerClassPair() yet.  I'm not even sure that is
 201      allowed.  */
 202   objc_mutex_lock (__objc_runtime_mutex);
 203
 204   /* Count how many ivars we have.  */
 205   ivar_list = class_->ivars;
 206   count = ivar_list->ivar_count;
 207
 208   if (count != 0)
 209     {
 210       unsigned int i = 0;
 211
 212       /* Allocate enough memory to hold them.  */
 213       returnValue = (struct objc_ivar **)(malloc (sizeof (struct objc_ivar *) * (count + 1)));
 214
 215       /* Copy the ivars.  */
 216       for (i = 0; i < count; i++)
 217         {
 218           returnValue[i] = &(ivar_list->ivar_list[i]);
 219         }
 220
 221       returnValue[i] = NULL;
 222     }
 223
 224   objc_mutex_unlock (__objc_runtime_mutex);
 225
 226   if (numberOfReturnedIvars)
 227     *numberOfReturnedIvars = count;
 228
 229   return returnValue;
 230 }