scoped_cftyperef.h revision 731df977c0511bca2206b5f333555b1205ff1f43 
1// Copyright (c) 2010 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_CFTYPEREF_H_
6#define BASE_MAC_SCOPED_CFTYPEREF_H_
7#pragma once
8
9#include <CoreFoundation/CoreFoundation.h>
10
11#include "base/basictypes.h"
12#include "base/compiler_specific.h"
13
14namespace base {
15namespace mac {
16
17// ScopedCFTypeRef<> is patterned after scoped_ptr<>, but maintains ownership
18// of a CoreFoundation object: any object that can be represented as a
19// CFTypeRef.  Style deviations here are solely for compatibility with
20// scoped_ptr<>'s interface, with which everyone is already familiar.
21//
22// When ScopedCFTypeRef<> takes ownership of an object (in the constructor or
23// in reset()), it takes over the caller's existing ownership claim.  The
24// caller must own the object it gives to ScopedCFTypeRef<>, and relinquishes
25// an ownership claim to that object.  ScopedCFTypeRef<> does not call
26// CFRetain().
27template<typename CFT>
28class ScopedCFTypeRef {
29 public:
30  typedef CFT element_type;
31
32  explicit ScopedCFTypeRef(CFT object = NULL)
33      : object_(object) {
34  }
35
36  ~ScopedCFTypeRef() {
37    if (object_)
38      CFRelease(object_);
39  }
40
41  void reset(CFT object = NULL) {
42    if (object_)
43      CFRelease(object_);
44    object_ = object;
45  }
46
47  bool operator==(CFT that) const {
48    return object_ == that;
49  }
50
51  bool operator!=(CFT that) const {
52    return object_ != that;
53  }
54
55  operator CFT() const {
56    return object_;
57  }
58
59  CFT get() const {
60    return object_;
61  }
62
63  void swap(ScopedCFTypeRef& that) {
64    CFT temp = that.object_;
65    that.object_ = object_;
66    object_ = temp;
67  }
68
69  // ScopedCFTypeRef<>::release() is like scoped_ptr<>::release.  It is NOT
70  // a wrapper for CFRelease().  To force a ScopedCFTypeRef<> object to call
71  // CFRelease(), use ScopedCFTypeRef<>::reset().
72  CFT release() WARN_UNUSED_RESULT {
73    CFT temp = object_;
74    object_ = NULL;
75    return temp;
76  }
77
78 private:
79  CFT object_;
80
81  DISALLOW_COPY_AND_ASSIGN(ScopedCFTypeRef);
82};
83
84}  // namespace mac
85}  // namespace base
86
87#endif  // BASE_MAC_SCOPED_CFTYPEREF_H_
88