Home | History | Annotate | Download | only in fetch 
      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();
     45     ResourceType* resource() const { return m_resource.get(); }
     46 
     47 protected:
     48     ResourceOwner();
     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>
     62 inline ResourceOwner<R, C>::ResourceOwner()
     63 {
     64 }
     65 
     66 template<class R, class C>
     67 inline ResourceOwner<R, C>::~ResourceOwner()
     68 {
     69     clearResource();
     70 }
     71 
     72 template<class R, class C>
     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>
     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>
    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