diff -r 000000000000 -r 4f2f89ce4247 WebKit2/UIProcess/WebBackForwardList.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKit2/UIProcess/WebBackForwardList.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) 2010 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "WebBackForwardList.h"
+
+#include "WebPageProxy.h"
+
+namespace WebKit {
+
+static const unsigned DefaultCapacity = 100;
+static const unsigned NoCurrentItemIndex = UINT_MAX;
+
+WebBackForwardList::WebBackForwardList(WebPageProxy* page)
+    : m_page(page)
+    , m_current(NoCurrentItemIndex)
+    , m_capacity(DefaultCapacity)
+    , m_closed(true)
+    , m_enabled(true)
+{
+}
+
+WebBackForwardList::~WebBackForwardList()
+{
+}
+
+void WebBackForwardList::addItem(WebBackForwardListItem* newItem)
+{
+    if (m_capacity == 0 || !m_enabled)
+        return;
+    
+    // Toss anything in the forward list    
+    if (m_current != NoCurrentItemIndex) {
+        unsigned targetSize = m_current + 1;
+        while (m_entries.size() > targetSize) {
+            RefPtr<WebBackForwardListItem> item = m_entries.last();
+            m_entries.removeLast();
+        }
+    }
+
+    // Toss the first item if the list is getting too big, as long as we're not using it
+    // (or even if we are, if we only want 1 entry).
+    if (m_entries.size() == m_capacity && (m_current != 0 || m_capacity == 1)) {
+        RefPtr<WebBackForwardListItem> item = m_entries[0];
+        m_entries.remove(0);
+        m_current--;
+        
+        if (m_page)
+            m_page->didChangeBackForwardList();
+    }
+
+    m_entries.insert(m_current + 1, newItem);
+    m_current++;
+
+    if (m_page)
+        m_page->didChangeBackForwardList();
+}
+
+void WebBackForwardList::goToItem(WebBackForwardListItem* item)
+{
+    if (!m_entries.size() || !item)
+        return;
+        
+    unsigned index = 0;
+    for (; index < m_entries.size(); ++index) {
+        if (m_entries[index] == item)
+            break;
+    }
+    if (index < m_entries.size()) {
+        m_current = index;
+        if (m_page)
+            m_page->didChangeBackForwardList();
+    }
+}
+
+WebBackForwardListItem* WebBackForwardList::currentItem()
+{
+    if (m_current != NoCurrentItemIndex)
+        return m_entries[m_current].get();
+    return 0;
+}
+
+WebBackForwardListItem* WebBackForwardList::backItem()
+{
+    if (m_current && m_current != NoCurrentItemIndex)
+        return m_entries[m_current - 1].get();
+    return 0;
+}
+
+WebBackForwardListItem* WebBackForwardList::forwardItem()
+{
+    if (m_entries.size() && m_current < m_entries.size() - 1)
+        return m_entries[m_current + 1].get();
+    return 0;
+}
+
+WebBackForwardListItem* WebBackForwardList::itemAtIndex(int index)
+{
+    // Do range checks without doing math on index to avoid overflow.
+    if (index < -static_cast<int>(m_current))
+        return 0;
+    
+    if (index > forwardListCount())
+        return 0;
+        
+    return m_entries[index + m_current].get();
+}
+
+int WebBackForwardList::backListCount()
+{
+    return m_current == NoCurrentItemIndex ? 0 : m_current;
+}
+
+int WebBackForwardList::forwardListCount()
+{
+    return m_current == NoCurrentItemIndex ? 0 : static_cast<int>(m_entries.size()) - (m_current + 1);
+}
+
+BackForwardListItemVector WebBackForwardList::backListWithLimit(unsigned limit)
+{
+    BackForwardListItemVector list;
+    unsigned size = std::min(backListCount(), static_cast<int>(limit));
+    if (!size)
+        return list;
+
+    list.resize(size);
+    for (unsigned i = std::max(m_current - limit, 0U), j = 0; i < m_current; ++i, ++j)
+        list[j] = m_entries[i];
+
+    return list;
+}
+
+BackForwardListItemVector WebBackForwardList::forwardListWithLimit(unsigned limit)
+{
+    BackForwardListItemVector list;
+    unsigned size = std::min(forwardListCount(), static_cast<int>(limit));
+    if (!size)
+        return list;
+
+    list.resize(size);
+    unsigned last = std::min(m_current + limit, static_cast<unsigned>(m_entries.size() - 1));
+    for (unsigned i = m_current + 1, j = 0; i <= last; ++i, ++j)
+        list[j] = m_entries[i];
+
+    return list;
+}
+
+// ImmutableArray::ImmutableArrayCallback [for WebBackForwardListItem] callbacks
+
+static void webBackForwardListItemRef(const void* item)
+{
+    static_cast<WebBackForwardListItem*>(const_cast<void*>(item))->ref();
+}
+
+static void webBackForwardListItemDeref(const void* item)
+{
+    static_cast<WebBackForwardListItem*>(const_cast<void*>(item))->deref();
+}
+
+PassRefPtr<ImmutableArray> WebBackForwardList::backListAsImmutableArrayWithLimit(unsigned limit)
+{
+    unsigned size = std::min(backListCount(), static_cast<int>(limit));
+    if (!size)
+        return ImmutableArray::create();
+
+    void** array = new void*[size];
+    for (unsigned i = std::max<int>(m_current - limit, 0), j = 0; i < m_current; ++i, ++j) {
+        WebBackForwardListItem* item = m_entries[i].get();
+        item->ref();
+        array[j] = item;
+    }
+
+    ImmutableArray::ImmutableArrayCallbacks callbacks = {
+        webBackForwardListItemRef,
+        webBackForwardListItemDeref
+    };
+    return ImmutableArray::adopt(array, size, &callbacks);
+}
+
+PassRefPtr<ImmutableArray> WebBackForwardList::forwardListAsImmutableArrayWithLimit(unsigned limit)
+{
+    unsigned size = std::min(forwardListCount(), static_cast<int>(limit));
+    if (!size)
+        return ImmutableArray::create();
+
+    void** array = new void*[size];
+    unsigned last = std::min(m_current + limit, static_cast<unsigned>(m_entries.size() - 1));
+    for (unsigned i = m_current + 1, j = 0; i <= last; ++i, ++j) {
+        WebBackForwardListItem* item = m_entries[i].get();
+        item->ref();
+        array[j] = item;
+    }
+
+    ImmutableArray::ImmutableArrayCallbacks callbacks = {
+        webBackForwardListItemRef,
+        webBackForwardListItemDeref
+    };
+    return ImmutableArray::adopt(array, size, &callbacks);
+}
+
+} // namespace WebKit