libobjc/methods.c

   1 /* GNU Objective C Runtime method related functions.
   2    Copyright (C) 2010-2018 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"      /* For __objc_runtime_mutex.  */
  30 #include <stdlib.h>                    /* For malloc.  */
  31
  32 SEL
  33 method_getName (struct objc_method * method)
  34 {
  35   if (method == NULL)
  36     return NULL;
  37
  38   return method->method_name;
  39 }
  40
  41 const char *
  42 method_getTypeEncoding (struct objc_method * method)
  43 {
  44   if (method == NULL)
  45     return NULL;
  46
  47   return method->method_types;
  48 }
  49
  50 IMP
  51 method_getImplementation (struct objc_method * method)
  52 {
  53   if (method == NULL)
  54     return NULL;
  55
  56   return method->method_imp;
  57 }
  58
  59 struct objc_method_description *
  60 method_getDescription (struct objc_method * method)
  61 {
  62   /* Note that the following returns NULL if method is NULL, which is
  63      fine.  */
  64   return (struct objc_method_description *)method;
  65 }
  66
  67 struct objc_method **
  68 class_copyMethodList (Class class_, unsigned int *numberOfReturnedMethods)
  69 {
  70   unsigned int count = 0;
  71   struct objc_method **returnValue = NULL;
  72   struct objc_method_list* method_list;
  73
  74   if (class_ == Nil)
  75     {
  76       if (numberOfReturnedMethods)
  77         *numberOfReturnedMethods = 0;
  78       return NULL;
  79     }
  80
  81   /* Lock the runtime mutex because the class methods may be
  82      concurrently modified.  */
  83   objc_mutex_lock (__objc_runtime_mutex);
  84
  85   /* Count how many methods we have.  */
  86   method_list = class_->methods;
  87
  88   while (method_list)
  89     {
  90       count = count + method_list->method_count;
  91       method_list = method_list->method_next;
  92     }
  93
  94   if (count != 0)
  95     {
  96       unsigned int i = 0;
  97
  98       /* Allocate enough memory to hold them.  */
  99       returnValue
 100         = (struct objc_method **)(malloc (sizeof (struct objc_method *)
 101                                           * (count + 1)));
 102
 103       /* Copy the methods.  */
 104       method_list = class_->methods;
 105
 106       while (method_list)
 107         {
 108           int j;
 109           for (j = 0; j < method_list->method_count; j++)
 110             {
 111               returnValue[i] = &(method_list->method_list[j]);
 112               i++;
 113             }
 114           method_list = method_list->method_next;
 115         }
 116
 117       returnValue[i] = NULL;
 118     }
 119
 120   objc_mutex_unlock (__objc_runtime_mutex);
 121
 122   if (numberOfReturnedMethods)
 123     *numberOfReturnedMethods = count;
 124
 125   return returnValue;
 126 }
 127
 128 IMP
 129 method_setImplementation (struct objc_method * method, IMP implementation)
 130 {
 131   IMP old_implementation;
 132
 133   if (method == NULL  ||  implementation == NULL)
 134     return NULL;
 135
 136   /* We lock the runtime mutex so that concurrent calls to change the
 137      same method won't conflict with each other.  */
 138   objc_mutex_lock (__objc_runtime_mutex);
 139
 140   old_implementation = method->method_imp;
 141   method->method_imp = implementation;
 142
 143   /* That was easy :-).  But now we need to find all classes that use
 144      this method, and update the IMP in the dispatch tables.  */
 145   __objc_update_classes_with_methods (method, NULL);
 146
 147   objc_mutex_unlock (__objc_runtime_mutex);
 148
 149   return old_implementation;
 150 }
 151
 152 void
 153 method_exchangeImplementations (struct objc_method * method_a, struct objc_method * method_b)
 154 {
 155   IMP old_implementation_a;
 156   IMP old_implementation_b;
 157
 158   if (method_a == NULL  ||  method_b == NULL)
 159     return;
 160
 161   /* We lock the runtime mutex so that concurrent calls to exchange
 162      similar methods won't conflict with each other.  Each of them
 163      should be atomic.  */
 164   objc_mutex_lock (__objc_runtime_mutex);
 165
 166   old_implementation_a = method_a->method_imp;
 167   old_implementation_b = method_b->method_imp;
 168
 169   method_a->method_imp = old_implementation_b;
 170   method_b->method_imp = old_implementation_a;
 171
 172   /* That was easy :-).  But now we need to find all classes that use
 173      these methods, and update the IMP in the dispatch tables.  */
 174   __objc_update_classes_with_methods (method_a, method_b);
 175
 176   objc_mutex_unlock (__objc_runtime_mutex);
 177 }