xref: /xnu-11215/libkern/os/object.h (revision 1031c584)
1 /*
2  * Copyright (c) 2011-2014 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 #if KERNEL
22 
23 #ifndef __OS_OBJECT__
24 #define __OS_OBJECT__
25 
26 #ifdef __APPLE__
27 #include <Availability.h>
28 #endif
29 #include <os/base.h>
30 
31 /*!
32  * @header
33  *
34  * @preprocinfo
35  * By default, libSystem objects such as GCD and XPC objects are declared as
36  * Objective-C types when building with an Objective-C compiler. This allows
37  * them to participate in ARC, in RR management by the Blocks runtime and in
38  * leaks checking by the static analyzer, and enables them to be added to Cocoa
39  * collections.
40  *
41  * NOTE: this requires explicit cancellation of dispatch sources and xpc
42  *       connections whose handler blocks capture the source/connection object,
43  *       resp. ensuring that such captures do not form retain cycles (e.g. by
44  *       declaring the source as __weak).
45  *
46  * To opt-out of this default behavior, add -DOS_OBJECT_USE_OBJC=0 to your
47  * compiler flags.
48  *
49  * This mode requires a platform with the modern Objective-C runtime, the
50  * Objective-C GC compiler option to be disabled, and at least a Mac OS X 10.8
51  * or iOS 6.0 deployment target.
52  */
53 
54 #ifndef OS_OBJECT_HAVE_OBJC_SUPPORT
55 #if defined(__OBJC__) && defined(__OBJC2__) && !defined(__OBJC_GC__) && ( \
56 	__MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_8 || \
57 	__IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_6_0)
58 #define OS_OBJECT_HAVE_OBJC_SUPPORT 1
59 #else
60 #define OS_OBJECT_HAVE_OBJC_SUPPORT 0
61 #endif
62 #endif
63 
64 #if OS_OBJECT_HAVE_OBJC_SUPPORT
65 #ifndef OS_OBJECT_USE_OBJC
66 #define OS_OBJECT_USE_OBJC 1
67 #endif
68 #elif defined(OS_OBJECT_USE_OBJC) && OS_OBJECT_USE_OBJC
69 /* Unsupported platform for OS_OBJECT_USE_OBJC=1 */
70 #undef OS_OBJECT_USE_OBJC
71 #define OS_OBJECT_USE_OBJC 0
72 #else
73 #define OS_OBJECT_USE_OBJC 0
74 #endif
75 
76 #if OS_OBJECT_USE_OBJC
77 #import <objc/NSObject.h>
78 #if defined(__has_attribute)
79 #if __has_attribute(objc_independent_class)
80 #define OS_OBJC_INDEPENDENT_CLASS __attribute__((objc_independent_class))
81 #endif
82 #endif // __has_attribute(objc_independent_class)
83 #ifndef OS_OBJC_INDEPENDENT_CLASS
84 #define OS_OBJC_INDEPENDENT_CLASS
85 #endif
86 #define OS_OBJECT_CLASS(name) OS_##name
87 #define OS_OBJECT_DECL_IMPL(name, ...) \
88 	        @protocol OS_OBJECT_CLASS(name) __VA_ARGS__ \
89 	        @end \
90 	        typedef NSObject<OS_OBJECT_CLASS(name)> \
91 	                        * OS_OBJC_INDEPENDENT_CLASS name##_t
92 #define OS_OBJECT_DECL(name, ...) \
93 	        OS_OBJECT_DECL_IMPL(name, <NSObject>)
94 #define OS_OBJECT_DECL_SUBCLASS(name, super) \
95 	        OS_OBJECT_DECL_IMPL(name, <OS_OBJECT_CLASS(super)>)
96 #if defined(__has_attribute)
97 #if __has_attribute(ns_returns_retained)
98 #define OS_OBJECT_RETURNS_RETAINED __attribute__((__ns_returns_retained__))
99 #else
100 #define OS_OBJECT_RETURNS_RETAINED
101 #endif
102 #if __has_attribute(ns_consumed)
103 #define OS_OBJECT_CONSUMED __attribute__((__ns_consumed__))
104 #else
105 #define OS_OBJECT_CONSUMED
106 #endif
107 #else
108 #define OS_OBJECT_RETURNS_RETAINED
109 #define OS_OBJECT_CONSUMED
110 #endif
111 #if defined(__has_feature)
112 #if __has_feature(objc_arc)
113 #define OS_OBJECT_BRIDGE __bridge
114 #define OS_WARN_RESULT_NEEDS_RELEASE
115 #else
116 #define OS_OBJECT_BRIDGE
117 #define OS_WARN_RESULT_NEEDS_RELEASE OS_WARN_RESULT
118 #endif
119 #else
120 #define OS_OBJECT_BRIDGE
121 #define OS_WARN_RESULT_NEEDS_RELEASE OS_WARN_RESULT
122 #endif
123 #ifndef OS_OBJECT_USE_OBJC_RETAIN_RELEASE
124 #if defined(__clang_analyzer__)
125 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 1
126 #elif defined(__has_feature)
127 #if __has_feature(objc_arc)
128 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 1
129 #else
130 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 0
131 #endif
132 #else
133 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 0
134 #endif
135 #endif
136 #else
137 /*! @parseOnly */
138 #define OS_OBJECT_RETURNS_RETAINED
139 /*! @parseOnly */
140 #define OS_OBJECT_CONSUMED
141 /*! @parseOnly */
142 #define OS_OBJECT_BRIDGE
143 /*! @parseOnly */
144 #define OS_WARN_RESULT_NEEDS_RELEASE OS_WARN_RESULT
145 #define OS_OBJECT_USE_OBJC_RETAIN_RELEASE 0
146 #endif
147 
148 #define OS_OBJECT_GLOBAL_OBJECT(type, object) ((OS_OBJECT_BRIDGE type)&(object))
149 
150 __BEGIN_DECLS
151 
152 /*!
153  * @function os_retain
154  *
155  * @abstract
156  * Increment the reference count of an os_object.
157  *
158  * @discussion
159  * On a platform with the modern Objective-C runtime this is exactly equivalent
160  * to sending the object the -[retain] message.
161  *
162  * @param object
163  * The object to retain.
164  *
165  * @result
166  * The retained object.
167  */
168 __OSX_AVAILABLE_STARTING(__MAC_10_12, __IPHONE_10_0)
169 OS_EXPORT
170 void*
171 os_retain(void *object);
172 #if OS_OBJECT_USE_OBJC
173 #undef os_retain
174 #define os_retain(object) [object retain]
175 #endif
176 
177 /*!
178  * @function os_release
179  *
180  * @abstract
181  * Decrement the reference count of a os_object.
182  *
183  * @discussion
184  * On a platform with the modern Objective-C runtime this is exactly equivalent
185  * to sending the object the -[release] message.
186  *
187  * @param object
188  * The object to release.
189  */
190 __OSX_AVAILABLE_STARTING(__MAC_10_12, __IPHONE_10_0)
191 OS_EXPORT
192 void
193 os_release(void *object);
194 #if OS_OBJECT_USE_OBJC
195 #undef os_release
196 #define os_release(object) [object release]
197 #endif
198 
199 #define fastpath(x) ((typeof(x))__builtin_expect((long)(x), ~0l))
200 #define slowpath(x) ((typeof(x))__builtin_expect((long)(x), 0l))
201 
202 __END_DECLS
203 
204 #endif /* OS_OBJECT file guard */
205 
206 #else /* KERNEL */
207 
208 /* This should use the libdispatch header */
209 #include_next <os/object.h>
210 
211 #endif /* KERNEL */
212