Split ImageResourceClient into ResourceClient and ImageResourceObserver [1/2]

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

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 
     This class provides all functionality needed for loading images, style sheets and html
     pages from the web. It has a memory cache for these objects.
 */
 
-#ifndef ResourceClientWalker_h
-#define ResourceClientWalker_h
+#ifndef ResourceClientOrObserverWalker_h
+#define ResourceClientOrObserverWalker_h
 
 #include "core/fetch/ResourceClient.h"
 #include "wtf/Allocator.h"
 #include "wtf/HashCountedSet.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 // Call this "walker" instead of iterator so people won't expect Qt or STL-style iterator interface.
 // Just keep calling next() on this. It's safe from deletions of items.
-template<typename T> class ResourceClientWalker {
+// ClientOrObserver is either ResourceClient or ImageResourceObserver, so that
+// this walker can be used both for ResourceClient and ImageResourceObserver.
+template<typename ClientOrObserver, typename T>
+class ResourceClientOrObserverWalker {
     STACK_ALLOCATED();
 public:
-    ResourceClientWalker(const HashCountedSet<ResourceClient*>& set)
+    explicit ResourceClientOrObserverWalker(const HashCountedSet<ClientOrObserver*>& set)
         : m_clientSet(set), m_clientVector(set.size()), m_index(0)
     {
         size_t clientIndex = 0;
         for (const auto& resourceClient : set)
             m_clientVector[clientIndex++] = resourceClient.key;
     }
 
     T* next()
     {
         size_t size = m_clientVector.size();
         while (m_index < size) {
-            ResourceClient* next = m_clientVector[m_index++];
+            ClientOrObserver* next = m_clientVector[m_index++];
             if (m_clientSet.contains(next)) {
                 ASSERT(T::isExpectedType(next));
                 return static_cast<T*>(next);
             }
         }
 
         return 0;
     }
 private:
-    const HashCountedSet<ResourceClient*>& m_clientSet;
-    Vector<ResourceClient*> m_clientVector;
+    const HashCountedSet<ClientOrObserver*>& m_clientSet;
+    Vector<ClientOrObserver*> m_clientVector;
     size_t m_index;
 };
 
+template<typename T>
+struct ResourceClientWalker : public ResourceClientOrObserverWalker<ResourceClient, T> {
+public:
+    explicit ResourceClientWalker(const HashCountedSet<ResourceClient*>& set)
+        : ResourceClientOrObserverWalker<ResourceClient, T>(set) { }
+};
+
 } // namespace blink
 
 #endif