1 /*
2 * Copyright (C) 2013 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #ifndef ResourceOwner_h
32 #define ResourceOwner_h
33
34 #include "core/fetch/ResourcePtr.h"
35
36 namespace WebCore {
37
38
39 template<class R, class C = typename R::ClientType>
40 class ResourceOwner : public C {
41 public:
42 typedef R ResourceType;
43
44 virtual ~ResourceOwner();
resource()45 ResourceType* resource() const { return m_resource.get(); }
46
47 protected:
48 ResourceOwner();
ResourceOwner(const ResourceOwner & other)49 ResourceOwner(const ResourceOwner& other) { setResource(other.resource()); }
50 explicit ResourceOwner(const ResourcePtr<ResourceType>&);
51
52 void setResource(const ResourcePtr<ResourceType>&);
53 void clearResource();
54
55 ResourceOwner& operator=(const ResourceOwner& other);
56
57 private:
58 ResourcePtr<ResourceType> m_resource;
59 };
60
61 template<class R, class C>
ResourceOwner()62 inline ResourceOwner<R, C>::ResourceOwner()
63 {
64 }
65
66 template<class R, class C>
~ResourceOwner()67 inline ResourceOwner<R, C>::~ResourceOwner()
68 {
69 clearResource();
70 }
71
72 template<class R, class C>
ResourceOwner(const ResourcePtr<R> & resource)73 inline ResourceOwner<R, C>::ResourceOwner(const ResourcePtr<R>& resource)
74 : m_resource(resource)
75 {
76 if (m_resource)
77 m_resource->addClient(this);
78 }
79
80 template<class R, class C>
setResource(const ResourcePtr<R> & newResource)81 inline void ResourceOwner<R, C>::setResource(const ResourcePtr<R>& newResource)
82 {
83 if (newResource == m_resource)
84 return;
85
86 // Some ResourceClient implementations reenter this so
87 // we need to prevent double removal.
88 if (ResourcePtr<ResourceType> oldResource = m_resource) {
89 m_resource.clear();
90 oldResource->removeClient(this);
91 }
92
93 if (newResource) {
94 m_resource = newResource;
95 m_resource->addClient(this);
96 }
97 }
98
99 template<class R, class C>
clearResource()100 inline void ResourceOwner<R, C>::clearResource()
101 {
102 setResource(0);
103 }
104
105 template<class R, class C>
106 inline ResourceOwner<R, C>& ResourceOwner<R, C>::operator=(const ResourceOwner<R, C>& other)
107 {
108 if (this == &other)
109 return *this;
110 setResource(other.resource());
111 return *this;
112 }
113
114 } // namespace WebCore
115
116 #endif
117