1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef BASE_MAC_SCOPED_NSOBJECT_H_
6 #define BASE_MAC_SCOPED_NSOBJECT_H_
7
8 #include <type_traits>
9
10 // Include NSObject.h directly because Foundation.h pulls in many dependencies.
11 // (Approx 100k lines of code versus 1.5k for NSObject.h). scoped_nsobject gets
12 // singled out because it is most typically included from other header files.
13 #import <Foundation/NSObject.h>
14
15 #include "base/compiler_specific.h"
16 #include "base/mac/scoped_typeref.h"
17
18 @class NSAutoreleasePool;
19
20 namespace base {
21
22 // scoped_nsobject<> is patterned after scoped_ptr<>, but maintains ownership
23 // of an NSObject subclass object. Style deviations here are solely for
24 // compatibility with scoped_ptr<>'s interface, with which everyone is already
25 // familiar.
26 //
27 // scoped_nsobject<> takes ownership of an object (in the constructor or in
28 // reset()) by taking over the caller's existing ownership claim. The caller
29 // must own the object it gives to scoped_nsobject<>, and relinquishes an
30 // ownership claim to that object. scoped_nsobject<> does not call -retain,
31 // callers have to call this manually if appropriate.
32 //
33 // scoped_nsprotocol<> has the same behavior as scoped_nsobject, but can be used
34 // with protocols.
35 //
36 // scoped_nsobject<> is not to be used for NSAutoreleasePools. For
37 // NSAutoreleasePools use ScopedNSAutoreleasePool from
38 // scoped_nsautorelease_pool.h instead.
39 // We check for bad uses of scoped_nsobject and NSAutoreleasePool at compile
40 // time with a template specialization (see below).
41
42 namespace internal {
43
44 template <typename NST>
45 struct ScopedNSProtocolTraits {
InvalidValueScopedNSProtocolTraits46 static NST InvalidValue() { return nil; }
RetainScopedNSProtocolTraits47 static NST Retain(NST nst) { return [nst retain]; }
ReleaseScopedNSProtocolTraits48 static void Release(NST nst) { [nst release]; }
49 };
50
51 } // namespace internal
52
53 template <typename NST>
54 class scoped_nsprotocol
55 : public ScopedTypeRef<NST, internal::ScopedNSProtocolTraits<NST>> {
56 public:
57 using ScopedTypeRef<NST,
58 internal::ScopedNSProtocolTraits<NST>>::ScopedTypeRef;
59
60 // Shift reference to the autorelease pool to be released later.
autorelease()61 NST autorelease() { return [this->release() autorelease]; }
62 };
63
64 // Free functions
65 template <class C>
swap(scoped_nsprotocol<C> & p1,scoped_nsprotocol<C> & p2)66 void swap(scoped_nsprotocol<C>& p1, scoped_nsprotocol<C>& p2) {
67 p1.swap(p2);
68 }
69
70 template <class C>
71 bool operator==(C p1, const scoped_nsprotocol<C>& p2) {
72 return p1 == p2.get();
73 }
74
75 template <class C>
76 bool operator!=(C p1, const scoped_nsprotocol<C>& p2) {
77 return p1 != p2.get();
78 }
79
80 template <typename NST>
81 class scoped_nsobject : public scoped_nsprotocol<NST*> {
82 public:
83 using scoped_nsprotocol<NST*>::scoped_nsprotocol;
84
85 static_assert(std::is_same<NST, NSAutoreleasePool>::value == false,
86 "Use ScopedNSAutoreleasePool instead");
87 };
88
89 // Specialization to make scoped_nsobject<id> work.
90 template<>
91 class scoped_nsobject<id> : public scoped_nsprotocol<id> {
92 public:
93 using scoped_nsprotocol<id>::scoped_nsprotocol;
94 };
95
96 } // namespace base
97
98 #endif // BASE_MAC_SCOPED_NSOBJECT_H_
99