1/*
2 * Copyright (C) 2008 Apple 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
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef ResourcePtr_h
27#define ResourcePtr_h
28
29#include "core/loader/cache/Resource.h"
30
31namespace WebCore {
32
33class ResourcePtrBase {
34public:
35    ~ResourcePtrBase();
36
37    Resource* get() const { return m_resource; }
38    bool operator!() const { return !m_resource; }
39
40    // This conversion operator allows implicit conversion to bool but not to other integer types.
41    typedef Resource* ResourcePtrBase::*UnspecifiedBoolType;
42    operator UnspecifiedBoolType() const { return m_resource ? &ResourcePtrBase::m_resource : 0; }
43
44protected:
45    ResourcePtrBase() : m_resource(0) { }
46    ResourcePtrBase(Resource*);
47    ResourcePtrBase(const ResourcePtrBase&);
48
49    void setResource(Resource*);
50
51private:
52    ResourcePtrBase& operator=(const ResourcePtrBase&) { return *this; }
53
54    friend class Resource;
55
56    Resource* m_resource;
57};
58
59inline ResourcePtrBase::ResourcePtrBase(Resource* res)
60    : m_resource(res)
61{
62    if (m_resource)
63        m_resource->registerHandle(this);
64}
65
66inline ResourcePtrBase::~ResourcePtrBase()
67{
68    if (m_resource)
69        m_resource->unregisterHandle(this);
70}
71
72inline ResourcePtrBase::ResourcePtrBase(const ResourcePtrBase& o)
73    : m_resource(o.m_resource)
74{
75    if (m_resource)
76        m_resource->registerHandle(this);
77}
78
79template <class R> class ResourcePtr : public ResourcePtrBase {
80public:
81    ResourcePtr() { }
82    ResourcePtr(R* res) : ResourcePtrBase(res) { }
83    ResourcePtr(const ResourcePtr<R>& o) : ResourcePtrBase(o) { }
84    template<typename U> ResourcePtr(const ResourcePtr<U>& o) : ResourcePtrBase(o.get()) { }
85
86    R* get() const { return reinterpret_cast<R*>(ResourcePtrBase::get()); }
87    R* operator->() const { return get(); }
88
89    ResourcePtr& operator=(R* res) { setResource(res); return *this; }
90    ResourcePtr& operator=(const ResourcePtr& o) { setResource(o.get()); return *this; }
91    template<typename U> ResourcePtr& operator=(const ResourcePtr<U>& o) { setResource(o.get()); return *this; }
92
93    bool operator==(const ResourcePtrBase& o) const { return get() == o.get(); }
94    bool operator!=(const ResourcePtrBase& o) const { return get() != o.get(); }
95};
96
97template <class R, class RR> bool operator==(const ResourcePtr<R>& h, const RR* res)
98{
99    return h.get() == res;
100}
101template <class R, class RR> bool operator==(const RR* res, const ResourcePtr<R>& h)
102{
103    return h.get() == res;
104}
105template <class R, class RR> bool operator!=(const ResourcePtr<R>& h, const RR* res)
106{
107    return h.get() != res;
108}
109template <class R, class RR> bool operator!=(const RR* res, const ResourcePtr<R>& h)
110{
111    return h.get() != res;
112}
113}
114
115#endif
116