os/object.h

   1 /*
   2  * Copyright (c) 2011-2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 #ifndef __OS_OBJECT__
  22 #define __OS_OBJECT__
  23
  24 #ifdef __APPLE__
  25 #include <Availability.h>
  26 #endif
  27
  28 /*!
  29  * @header
  30  *
  31  * @preprocinfo
  32  * By default, libSystem objects such as GCD and XPC objects are declared as
  33  * Objective-C types when building with an Objective-C compiler. This allows
  34  * them to participate in ARC, in RR management by the Blocks runtime and in
  35  * leaks checking by the static analyzer, and enables them to be added to Cocoa
  36  * collections.
  37  *
  38  * NOTE: this requires explicit cancellation of dispatch sources and xpc
  39  *       connections whose handler blocks capture the source/connection object,
  40  *       resp. ensuring that such captures do not form retain cycles (e.g. by
  41  *       declaring the source as __weak).
  42  *
  43  * To opt-out of this default behavior, add -DOS_OBJECT_USE_OBJC=0 to your
  44  * compiler flags.
  45  *
  46  * This mode requires a platform with the modern Objective-C runtime, the
  47  * Objective-C GC compiler option to be disabled, and at least a Mac OS X 10.8
  48  * deployment target.
  49  */
  50
  51 #ifndef OS_OBJECT_HAVE_OBJC_SUPPORT
  52 #if defined(__OBJC__) && defined(__OBJC2__) && !defined(__OBJC_GC__) && ( \
  53                 __MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_8 || \
  54                 __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_6_0)
  55 #define OS_OBJECT_HAVE_OBJC_SUPPORT 1
  56 #else
  57 #define OS_OBJECT_HAVE_OBJC_SUPPORT 0
  58 #endif
  59 #endif
  60
  61 #if OS_OBJECT_HAVE_OBJC_SUPPORT
  62 #ifndef OS_OBJECT_USE_OBJC
  63 #define OS_OBJECT_USE_OBJC 1
  64 #endif
  65 #elif defined(OS_OBJECT_USE_OBJC) && OS_OBJECT_USE_OBJC
  66 /* Unsupported platform for OS_OBJECT_USE_OBJC=1 */
  67 #undef OS_OBJECT_USE_OBJC
  68 #define OS_OBJECT_USE_OBJC 0
  69 #else
  70 #define OS_OBJECT_USE_OBJC 0
  71 #endif
  72
  73 #if OS_OBJECT_USE_OBJC
  74 #import <Foundation/NSObject.h>
  75 #define OS_OBJECT_CLASS(name) OS_##name
  76 #define OS_OBJECT_DECL(name, ...) \
  77                 @protocol OS_OBJECT_CLASS(name) __VA_ARGS__ \
  78                 @end \
  79                 typedef NSObject<OS_OBJECT_CLASS(name)> *name##_t
  80 #define OS_OBJECT_DECL_SUBCLASS(name, super) \
  81                 OS_OBJECT_DECL(name, <OS_OBJECT_CLASS(super)>)
  82 #if defined(__has_attribute) && __has_attribute(ns_returns_retained)
  83 #define OS_OBJECT_RETURNS_RETAINED __attribute__((__ns_returns_retained__))
  84 #else
  85 #define OS_OBJECT_RETURNS_RETAINED
  86 #endif
  87 #if defined(__has_feature) && __has_feature(objc_arc)
  88 #define OS_OBJECT_BRIDGE __bridge
  89 #else
  90 #define OS_OBJECT_BRIDGE
  91 #endif
  92 #ifndef OS_OBJECT_USE_OBJC_RETAIN_RELEASE
  93 #if defined(__has_feature) && __has_feature(objc_arc) || \
  94                 defined(__clang_analyzer__)
  95 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 1
  96 #else
  97 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 0
  98 #endif
  99 #endif
 100 #else
 101 /*! @parseOnly */
 102 #define OS_OBJECT_RETURNS_RETAINED
 103 /*! @parseOnly */
 104 #define OS_OBJECT_BRIDGE
 105 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 0
 106 #endif
 107
 108 #endif