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 CachedResourceHandle_h
27#define CachedResourceHandle_h
28
29#include "CachedResource.h"
30
31namespace WebCore {
32
33    class CachedResourceHandleBase {
34    public:
35        ~CachedResourceHandleBase() { if (m_resource) m_resource->unregisterHandle(this); }
36        CachedResource* get() const { return m_resource; }
37
38        bool operator!() const { return !m_resource; }
39
40        // This conversion operator allows implicit conversion to bool but not to other integer types.
41        // Parenthesis is needed for winscw compiler to resolve class qualifier in this case.
42        typedef CachedResource* (CachedResourceHandleBase::*UnspecifiedBoolType);
43        operator UnspecifiedBoolType() const { return m_resource ? &CachedResourceHandleBase::m_resource : 0; }
44
45    protected:
46        CachedResourceHandleBase() : m_resource(0) {}
47        CachedResourceHandleBase(CachedResource* res) { m_resource = res; if (m_resource) m_resource->registerHandle(this); }
48        CachedResourceHandleBase(const CachedResourceHandleBase& o) : m_resource(o.m_resource) { if (m_resource) m_resource->registerHandle(this); }
49
50        void setResource(CachedResource*);
51
52    private:
53        CachedResourceHandleBase& operator=(const CachedResourceHandleBase&) { return *this; }
54
55        friend class CachedResource;
56
57        CachedResource* m_resource;
58    };
59
60    template <class R> class CachedResourceHandle : public CachedResourceHandleBase {
61    public:
62        CachedResourceHandle() { }
63        CachedResourceHandle(R* res);
64        CachedResourceHandle(const CachedResourceHandle<R>& o) : CachedResourceHandleBase(o) { }
65
66        R* get() const { return reinterpret_cast<R*>(CachedResourceHandleBase::get()); }
67        R* operator->() const { return get(); }
68
69        CachedResourceHandle& operator=(R* res) { setResource(res); return *this; }
70        CachedResourceHandle& operator=(const CachedResourceHandle& o) { setResource(o.get()); return *this; }
71        bool operator==(const CachedResourceHandleBase& o) const { return get() == o.get(); }
72        bool operator!=(const CachedResourceHandleBase& o) const { return get() != o.get(); }
73    };
74
75    // Don't inline for winscw compiler to prevent the compiler aggressively resolving
76    // the base class of R* when CachedResourceHandler<T>(R*) is inlined.  The bug is
77    // reported at: https://xdabug001.ext.nokia.com/bugzilla/show_bug.cgi?id=9812.
78    template <class R>
79#if !COMPILER(WINSCW)
80    inline
81#endif
82    CachedResourceHandle<R>::CachedResourceHandle(R* res) : CachedResourceHandleBase(res)
83    {
84    }
85
86    template <class R, class RR> bool operator==(const CachedResourceHandle<R>& h, const RR* res)
87    {
88        return h.get() == res;
89    }
90    template <class R, class RR> bool operator==(const RR* res, const CachedResourceHandle<R>& h)
91    {
92        return h.get() == res;
93    }
94    template <class R, class RR> bool operator!=(const CachedResourceHandle<R>& h, const RR* res)
95    {
96        return h.get() != res;
97    }
98    template <class R, class RR> bool operator!=(const RR* res, const CachedResourceHandle<R>& h)
99    {
100        return h.get() != res;
101    }
102}
103
104#endif
105