Move ResourceClient to Oilpan heap

third_party/WebKit/Source/core/fetch/ResourceClientWalker.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 ResourceClientOrObserverWalker_h
-#define ResourceClientOrObserverWalker_h
+#ifndef ResourceClientWalker_h
+#define ResourceClientWalker_h
 
 #include "core/fetch/ResourceClient.h"
+#include "platform/heap/Handle.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.
-// 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 {
+template<typename T>
+struct ResourceClientWalker {

[haraken, 2016/08/02 04:18:06]

I'd prefer using a class.

(Honestly speaking, I'm not quite sure of the benefit of having the
ResourceClientWalker class. The caller sites can just copyToVector the hash
counted set and iterate the vector.)

[yhirano, 2016/08/03 10:40:28]

Done.

This class is doing two extra conversions: One is WeakMember to Member and
another is ResourceClient* to T*. copyToVector can handle neither conversions.

[haraken, 2016/08/16 11:55:44]

I'm just curious but why do you need to convert ResourceClient* to T*? Can we
avoid the conversion by adding some virtual method on ResourceClient?

[yhirano, 2016/08/17 08:36:09]

The right direction would be making each Resource subclass have its
ResourceClient.

     STACK_ALLOCATED();
 public:
-    explicit ResourceClientOrObserverWalker(const HashCountedSet<ClientOrObserver*>& set)
-        : m_clientSet(set), m_clientVector(set.size()), m_index(0)
+    explicit ResourceClientWalker(const HeapHashCountedSet<WeakMember<ResourceClient>>& set)
+        : m_clientSet(set)
     {
-        size_t clientIndex = 0;
-        for (const auto& resourceClient : set)
-            m_clientVector[clientIndex++] = resourceClient.key;
+        m_clientVector.reserveCapacity(set.size());
+        for (const auto& keyvalue : set) {
+            ResourceClient* client = keyvalue.key;
+            if (client) {
+                // |client| can be null, as the container holds weak pointers.

[haraken, 2016/08/02 04:18:06]

I guess |client| cannot be null because null-ed entries are automatically
removed from the hash counted set.

[yhirano, 2016/08/03 10:40:28]

Done.

+                m_clientVector.append(client);
+            }
+        }
     }
 
     T* next()
     {
         size_t size = m_clientVector.size();
         while (m_index < size) {
-            ClientOrObserver* next = m_clientVector[m_index++];
+            ResourceClient* next = m_clientVector[m_index++];
+            DCHECK(next);
             if (m_clientSet.contains(next)) {
-                ASSERT(T::isExpectedType(next));
+                DCHECK(T::isExpectedType(next));
                 return static_cast<T*>(next);
             }
         }
+        return nullptr;
+    }
 
-        return 0;
-    }
 private:
-    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) { }
+    const HeapHashCountedSet<WeakMember<ResourceClient>>& m_clientSet;
+    HeapVector<Member<ResourceClient>> m_clientVector;
+    size_t m_index = 0;
 };
 
 } // namespace blink
 
 #endif