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 (TARGET_OS_IPHONE && __LP64__)  ||  TARGET_OS_WATCH
  63 #define OBJC_BOOL_IS_BOOL 1
  64 typedef bool BOOL;
  65 #else
  66 #define OBJC_BOOL_IS_CHAR 1
  67 typedef signed char BOOL;
  68 // BOOL is explicitly signed so @encode(BOOL) == "c" rather than "C"
  69 // even if -funsigned-char is used.
  70 #endif
  71
  72 #if __has_feature(objc_bool)
  73 #define YES __objc_yes
  74 #define NO  __objc_no
  75 #else
  76 #define YES ((BOOL)1)
  77 #define NO  ((BOOL)0)
  78 #endif
  79
  80 #ifndef Nil
  81 # if __has_feature(cxx_nullptr)
  82 #   define Nil nullptr
  83 # else
  84 #   define Nil __DARWIN_NULL
  85 # endif
  86 #endif
  87
  88 #ifndef nil
  89 # if __has_feature(cxx_nullptr)
  90 #   define nil nullptr
  91 # else
  92 #   define nil __DARWIN_NULL
  93 # endif
  94 #endif
  95
  96 #if ! (defined(__OBJC_GC__)  ||  __has_feature(objc_arc))
  97 #define __strong /* empty */
  98 #endif
  99
 100 #if !__has_feature(objc_arc)
 101 #define __unsafe_unretained /* empty */
 102 #define __autoreleasing /* empty */
 103 #endif
 104
 105
 106 /**
 107  * Returns the name of the method specified by a given selector.
 108  *
 109  * @param sel A pointer of type \c SEL. Pass the selector whose name you wish to determine.
 110  *
 111  * @return A C string indicating the name of the selector.
 112  */
 113 OBJC_EXPORT const char *sel_getName(SEL sel)
 114     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 115
 116 /**
 117  * Registers a method with the Objective-C runtime system, maps the method
 118  * name to a selector, and returns the selector value.
 119  *
 120  * @param str A pointer to a C string. Pass the name of the method you wish to register.
 121  *
 122  * @return A pointer of type SEL specifying the selector for the named method.
 123  *
 124  * @note You must register a method name with the Objective-C runtime system to obtain the
 125  *  method’s selector before you can add the method to a class definition. If the method name
 126  *  has already been registered, this function simply returns the selector.
 127  */
 128 OBJC_EXPORT SEL sel_registerName(const char *str)
 129     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 130
 131 /**
 132  * Returns the class name of a given object.
 133  *
 134  * @param obj An Objective-C object.
 135  *
 136  * @return The name of the class of which \e obj is an instance.
 137  */
 138 OBJC_EXPORT const char *object_getClassName(id obj)
 139     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 140
 141 /**
 142  * Returns a pointer to any extra bytes allocated with an instance given object.
 143  *
 144  * @param obj An Objective-C object.
 145  *
 146  * @return A pointer to any extra bytes allocated with \e obj. If \e obj was
 147  *   not allocated with any extra bytes, then dereferencing the returned pointer is undefined.
 148  *
 149  * @note This function returns a pointer to any extra bytes allocated with the instance
 150  *  (as specified by \c class_createInstance with extraBytes>0). This memory follows the
 151  *  object's ordinary ivars, but may not be adjacent to the last ivar.
 152  * @note The returned pointer is guaranteed to be pointer-size aligned, even if the area following
 153  *  the object's last ivar is less aligned than that. Alignment greater than pointer-size is never
 154  *  guaranteed, even if the area following the object's last ivar is more aligned than that.
 155  * @note In a garbage-collected environment, the memory is scanned conservatively.
 156  */
 157 OBJC_EXPORT void *object_getIndexedIvars(id obj)
 158     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 159
 160 /**
 161  * Identifies a selector as being valid or invalid.
 162  *
 163  * @param sel The selector you want to identify.
 164  *
 165  * @return YES if selector is valid and has a function implementation, NO otherwise.
 166  *
 167  * @warning On some platforms, an invalid reference (to invalid memory addresses) can cause
 168  *  a crash.
 169  */
 170 OBJC_EXPORT BOOL sel_isMapped(SEL sel)
 171     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 172
 173 /**
 174  * Registers a method name with the Objective-C runtime system.
 175  *
 176  * @param str A pointer to a C string. Pass the name of the method you wish to register.
 177  *
 178  * @return A pointer of type SEL specifying the selector for the named method.
 179  *
 180  * @note The implementation of this method is identical to the implementation of \c sel_registerName.
 181  * @note Prior to OS X version 10.0, this method tried to find the selector mapped to the given name
 182  *  and returned \c NULL if the selector was not found. This was changed for safety, because it was
 183  *  observed that many of the callers of this function did not check the return value for \c NULL.
 184  */
 185 OBJC_EXPORT SEL sel_getUid(const char *str)
 186     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 187
 188
 189 // Obsolete ARC conversions. Deprecation forthcoming.
 190 // Use CFBridgingRetain, CFBridgingRelease, and __bridge casts instead.
 191
 192 typedef const void* objc_objectptr_t;
 193
 194 #if __has_feature(objc_arc)
 195 #   define objc_retainedObject(o) ((__bridge_transfer id)(objc_objectptr_t)(o))
 196 #   define objc_unretainedObject(o) ((__bridge id)(objc_objectptr_t)(o))
 197 #   define objc_unretainedPointer(o) ((__bridge objc_objectptr_t)(id)(o))
 198 #else
 199 #   define objc_retainedObject(o) ((id)(objc_objectptr_t)(o))
 200 #   define objc_unretainedObject(o) ((id)(objc_objectptr_t)(o))
 201 #   define objc_unretainedPointer(o) ((objc_objectptr_t)(id)(o))
 202 #endif
 203
 204
 205 #if !__OBJC2__
 206
 207 // The following declarations are provided here for source compatibility.
 208
 209 #if defined(__LP64__)
 210     typedef long arith_t;
 211     typedef unsigned long uarith_t;
 212 #   define ARITH_SHIFT 32
 213 #else
 214     typedef int arith_t;
 215     typedef unsigned uarith_t;
 216 #   define ARITH_SHIFT 16
 217 #endif
 218
 219 typedef char *STR;
 220
 221 #define ISSELECTOR(sel) sel_isMapped(sel)
 222 #define SELNAME(sel)    sel_getName(sel)
 223 #define SELUID(str)     sel_getUid(str)
 224 #define NAMEOF(obj)     object_getClassName(obj)
 225 #define IV(obj)         object_getIndexedIvars(obj)
 226
 227 #endif
 228
 229 #endif  /* _OBJC_OBJC_H_ */