CachedResourceClientWalker.h   [plain text]

    Copyright (C) 1998 Lars Knoll (
    Copyright (C) 2001 Dirk Mueller <>
    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
    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.

#pragma once

#include "CachedResourceClient.h"
#include <wtf/HashCountedSet.h>
#include <wtf/Vector.h>

namespace WebCore {

// 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 CachedResourceClientWalker {
    CachedResourceClientWalker(const HashCountedSet<CachedResourceClient*>& clientSet)
        : m_clientSet(clientSet)
        , m_clientVector(clientSet.size())
        size_t clientIndex = 0;
        for (const auto& client : clientSet)
            m_clientVector[clientIndex++] = client.key;

    T* next()
        size_t size = m_clientVector.size();
        while (m_index < size) {
            CachedResourceClient* next = m_clientVector[m_index++];
            if (m_clientSet.contains(next)) {
                RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(T::expectedType() == CachedResourceClient::expectedType() || next->resourceClientType() == T::expectedType());
                return static_cast<T*>(next);
        return nullptr;
    const HashCountedSet<CachedResourceClient*>& m_clientSet;
    Vector<CachedResourceClient*> m_clientVector;
    size_t m_index { 0 };

} // namespace WebCore