third_party/WebKit/Source/core/fetch/ResourcePtr.h

   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/CoreExport.h"
  30 #include "core/fetch/Resource.h"
  31 #include "wtf/Allocator.h"
  32
  33 namespace blink {
  34
  35 class CORE_EXPORT ResourcePtrBase {
  36     ALLOW_ONLY_INLINE_ALLOCATION();
  37 public:
  38     Resource* get() const { return m_resource; }
  39     bool operator!() const { return !m_resource; }
  40     void clear() { setResource(nullptr); }
  41
  42     // This conversion operator allows implicit conversion to bool but not to other integer types.
  43     typedef Resource* ResourcePtrBase::*UnspecifiedBoolType;
  44     operator UnspecifiedBoolType() const { return m_resource ? &ResourcePtrBase::m_resource : nullptr; }
  45
  46 protected:
  47     ResourcePtrBase() : m_resource(nullptr) { }
  48     explicit ResourcePtrBase(Resource*);
  49     explicit ResourcePtrBase(const ResourcePtrBase&);
  50     ~ResourcePtrBase();
  51
  52     void setResource(Resource*);
  53
  54 private:
  55     friend class Resource;
  56     ResourcePtrBase& operator=(const ResourcePtrBase&) = delete;
  57
  58     // The lifetime of the Resource object is explicitly managed by
  59     // reference-counting.
  60     GC_PLUGIN_IGNORE("503485")
  61     Resource* m_resource;
  62 };
  63
  64 inline ResourcePtrBase::ResourcePtrBase(Resource* res)
  65     : m_resource(res)
  66 {
  67     if (m_resource)
  68         m_resource->registerHandle(this);
  69 }
  70
  71 inline ResourcePtrBase::~ResourcePtrBase()
  72 {
  73     if (m_resource)
  74         m_resource->unregisterHandle(this);
  75 }
  76
  77 inline ResourcePtrBase::ResourcePtrBase(const ResourcePtrBase& o)
  78     : m_resource(o.m_resource)
  79 {
  80     if (m_resource)
  81         m_resource->registerHandle(this);
  82 }
  83
  84 template <class R> class ResourcePtr final : public ResourcePtrBase {
  85 public:
  86     ResourcePtr() { }
  87     ResourcePtr(R* res) : ResourcePtrBase(res) { }
  88     ResourcePtr(const ResourcePtr<R>& o) : ResourcePtrBase(o) { }
  89     template<typename U> ResourcePtr(const ResourcePtr<U>& o) : ResourcePtrBase(cast(o.get())) { }
  90
  91     R* get() const { return static_cast<R*>(ResourcePtrBase::get()); }
  92     R* operator->() const { return get(); }
  93
  94     ResourcePtr& operator=(R* res) { setResource(res); return *this; }
  95     ResourcePtr& operator=(const ResourcePtr& o) { setResource(o.get()); return *this; }
  96     template<typename U> ResourcePtr& operator=(const ResourcePtr<U>& o) { setResource(cast(o.get())); return *this; }
  97
  98     bool operator==(const ResourcePtrBase& o) const { return get() == o.get(); }
  99     bool operator!=(const ResourcePtrBase& o) const { return get() != o.get(); }
 100 private:
 101     template<typename U> static R* cast(U* u) { return u; }
 102 };
 103
 104 template <class R, class RR> bool operator==(const ResourcePtr<R>& h, const RR* res)
 105 {
 106     return h.get() == res;
 107 }
 108 template <class R, class RR> bool operator==(const RR* res, const ResourcePtr<R>& h)
 109 {
 110     return h.get() == res;
 111 }
 112 template <class R, class RR> bool operator!=(const ResourcePtr<R>& h, const RR* res)
 113 {
 114     return h.get() != res;
 115 }
 116 template <class R, class RR> bool operator!=(const RR* res, const ResourcePtr<R>& h)
 117 {
 118     return h.get() != res;
 119 }
 120 }
 121
 122 #endif