runtime/objc.h

   1 /*
   2  * Copyright (c) 1999-2007 Apple Inc.  All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  *      objc.h
  25  *      Copyright 1988-1996, NeXT Software, Inc.
  26  */
  27
  28 #ifndef _OBJC_OBJC_H_
  29 #define _OBJC_OBJC_H_
  30
  31 #include <sys/types.h>      // for __DARWIN_NULL
  32 #include <Availability.h>
  33 #include <objc/objc-api.h>
  34 #include <stdbool.h>
  35
  36 #if !OBJC_TYPES_DEFINED
  37 /// An opaque type that represents an Objective-C class.
  38 typedef struct objc_class *Class;
  39
  40 /// Represents an instance of a class.
  41 struct objc_object {
  42     Class isa  OBJC_ISA_AVAILABILITY;
  43 };
  44
  45 /// A pointer to an instance of a class.
  46 typedef struct objc_object *id;
  47 #endif
  48
  49 /// An opaque type that represents a method selector.
  50 typedef struct objc_selector *SEL;
  51
  52 /// A pointer to the function of a method implementation.
  53 #if !OBJC_OLD_DISPATCH_PROTOTYPES
  54 typedef void (*IMP)(void /* id, SEL, ... */ );
  55 #else
  56 typedef id (*IMP)(id, SEL, ...);
  57 #endif
  58
  59 #define OBJC_BOOL_DEFINED
  60
  61 /// Type to represent a boolean value.
  62 #if !defined(OBJC_HIDE_64) && TARGET_OS_IPHONE && __LP64__
  63 typedef bool BOOL;
  64 #else
  65 typedef signed char BOOL;
  66 // BOOL is explicitly signed so @encode(BOOL) == "c" rather than "C"
  67 // even if -funsigned-char is used.
  68 #endif
  69
  70 #if __has_feature(objc_bool)
  71 #define YES __objc_yes
  72 #define NO  __objc_no
  73 #else
  74 #define YES ((BOOL)1)
  75 #define NO  ((BOOL)0)
  76 #endif
  77
  78 #ifndef Nil
  79 # if __has_feature(cxx_nullptr)
  80 #   define Nil nullptr
  81 # else
  82 #   define Nil __DARWIN_NULL
  83 # endif
  84 #endif
  85
  86 #ifndef nil
  87 # if __has_feature(cxx_nullptr)
  88 #   define nil nullptr
  89 # else
  90 #   define nil __DARWIN_NULL
  91 # endif
  92 #endif
  93
  94 #if ! (defined(__OBJC_GC__)  ||  __has_feature(objc_arc))
  95 #define __strong /* empty */
  96 #endif
  97
  98 #if !__has_feature(objc_arc)
  99 #define __unsafe_unretained /* empty */
 100 #define __autoreleasing /* empty */
 101 #endif
 102
 103
 104 /**
 105  * Returns the name of the method specified by a given selector.
 106  *
 107  * @param sel A pointer of type \c SEL. Pass the selector whose name you wish to determine.
 108  *
 109  * @return A C string indicating the name of the selector.
 110  */
 111 OBJC_EXPORT const char *sel_getName(SEL sel)
 112     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 113
 114 /**
 115  * Registers a method with the Objective-C runtime system, maps the method
 116  * name to a selector, and returns the selector value.
 117  *
 118  * @param str A pointer to a C string. Pass the name of the method you wish to register.
 119  *
 120  * @return A pointer of type SEL specifying the selector for the named method.
 121  *
 122  * @note You must register a method name with the Objective-C runtime system to obtain the
 123  *  method’s selector before you can add the method to a class definition. If the method name
 124  *  has already been registered, this function simply returns the selector.
 125  */
 126 OBJC_EXPORT SEL sel_registerName(const char *str)
 127     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 128
 129 /**
 130  * Returns the class name of a given object.
 131  *
 132  * @param obj An Objective-C object.
 133  *
 134  * @return The name of the class of which \e obj is an instance.
 135  */
 136 OBJC_EXPORT const char *object_getClassName(id obj)
 137     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 138
 139 /**
 140  * Returns a pointer to any extra bytes allocated with an instance given object.
 141  *
 142  * @param obj An Objective-C object.
 143  *
 144  * @return A pointer to any extra bytes allocated with \e obj. If \e obj was
 145  *   not allocated with any extra bytes, then dereferencing the returned pointer is undefined.
 146  *
 147  * @note This function returns a pointer to any extra bytes allocated with the instance
 148  *  (as specified by \c class_createInstance with extraBytes>0). This memory follows the
 149  *  object's ordinary ivars, but may not be adjacent to the last ivar.
 150  * @note The returned pointer is guaranteed to be pointer-size aligned, even if the area following
 151  *  the object's last ivar is less aligned than that. Alignment greater than pointer-size is never
 152  *  guaranteed, even if the area following the object's last ivar is more aligned than that.
 153  * @note In a garbage-collected environment, the memory is scanned conservatively.
 154  */
 155 OBJC_EXPORT void *object_getIndexedIvars(id obj)
 156     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 157
 158 /**
 159  * Identifies a selector as being valid or invalid.
 160  *
 161  * @param sel The selector you want to identify.
 162  *
 163  * @return YES if selector is valid and has a function implementation, NO otherwise.
 164  *
 165  * @warning On some platforms, an invalid reference (to invalid memory addresses) can cause
 166  *  a crash.
 167  */
 168 OBJC_EXPORT BOOL sel_isMapped(SEL sel)
 169     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 170
 171 /**
 172  * Registers a method name with the Objective-C runtime system.
 173  *
 174  * @param str A pointer to a C string. Pass the name of the method you wish to register.
 175  *
 176  * @return A pointer of type SEL specifying the selector for the named method.
 177  *
 178  * @note The implementation of this method is identical to the implementation of \c sel_registerName.
 179  * @note Prior to OS X version 10.0, this method tried to find the selector mapped to the given name
 180  *  and returned \c NULL if the selector was not found. This was changed for safety, because it was
 181  *  observed that many of the callers of this function did not check the return value for \c NULL.
 182  */
 183 OBJC_EXPORT SEL sel_getUid(const char *str)
 184     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 185
 186
 187 // Obsolete ARC conversions. Deprecation forthcoming.
 188 // Use CFBridgingRetain, CFBridgingRelease, and __bridge casts instead.
 189
 190 typedef const void* objc_objectptr_t;
 191
 192 #if __has_feature(objc_arc)
 193 #   define objc_retainedObject(o) ((__bridge_transfer id)(objc_objectptr_t)(o))
 194 #   define objc_unretainedObject(o) ((__bridge id)(objc_objectptr_t)(o))
 195 #   define objc_unretainedPointer(o) ((__bridge objc_objectptr_t)(id)(o))
 196 #else
 197 #   define objc_retainedObject(o) ((id)(objc_objectptr_t)(o))
 198 #   define objc_unretainedObject(o) ((id)(objc_objectptr_t)(o))
 199 #   define objc_unretainedPointer(o) ((objc_objectptr_t)(id)(o))
 200 #endif
 201
 202
 203 #if !__OBJC2__
 204
 205 // The following declarations are provided here for source compatibility.
 206
 207 #if defined(__LP64__)
 208     typedef long arith_t;
 209     typedef unsigned long uarith_t;
 210 #   define ARITH_SHIFT 32
 211 #else
 212     typedef int arith_t;
 213     typedef unsigned uarith_t;
 214 #   define ARITH_SHIFT 16
 215 #endif
 216
 217 typedef char *STR;
 218
 219 #define ISSELECTOR(sel) sel_isMapped(sel)
 220 #define SELNAME(sel)    sel_getName(sel)
 221 #define SELUID(str)     sel_getUid(str)
 222 #define NAMEOF(obj)     object_getClassName(obj)
 223 #define IV(obj)         object_getIndexedIvars(obj)
 224
 225 #endif
 226
 227 #endif  /* _OBJC_OBJC_H_ */