Source/WebKit2/UIProcess/cf/WebBackForwardListCF.cpp - platform/external/chromium_org/third_party/WebKit - Git at Google

 /*
  * Copyright (C) 2010, 2011, 2012 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 "config.h"
 #include "WebBackForwardList.h"

 #include "Logging.h"
 #include <wtf/RetainPtr.h>
 #include <CoreFoundation/CoreFoundation.h>

 using namespace WebCore;

 namespace WebKit {

 static uint64_t generateWebBackForwardItemID()
 {
     // These IDs exist in the UIProcess for items created by the UIProcess.
     // The IDs generated here need to never collide with the IDs created in WebBackForwardListProxy in the WebProcess.
     // We accomplish this by starting from 2, and only ever using even ids.
     static uint64_t uniqueHistoryItemID = 0;
     uniqueHistoryItemID += 2;
     return uniqueHistoryItemID;
 }

 static CFIndex currentVersion = 1;
 DEFINE_STATIC_GETTER(CFNumberRef, SessionHistoryCurrentVersion, (CFNumberCreate(0, kCFNumberCFIndexType, &currentVersion)));

 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryVersionKey, (CFSTR("SessionHistoryVersion")));
 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryCurrentIndexKey, (CFSTR("SessionHistoryCurrentIndex")));
 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntriesKey, (CFSTR("SessionHistoryEntries")));
 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryTitleKey, (CFSTR("SessionHistoryEntryTitle")));
 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryURLKey, (CFSTR("SessionHistoryEntryURL")));
 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryOriginalURLKey, (CFSTR("SessionHistoryEntryOriginalURL")));
 DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryDataKey, (CFSTR("SessionHistoryEntryData")));

 static bool extractBackForwardListEntriesFromArray(CFArrayRef, BackForwardListItemVector&);

 static CFDictionaryRef createEmptySessionHistoryDictionary()
 {
     static const void* keys[1] = { SessionHistoryVersionKey() };
     static const void* values[1] = { SessionHistoryCurrentVersion() };

     return CFDictionaryCreate(0, keys, values, 1, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
 }

 CFDictionaryRef WebBackForwardList::createCFDictionaryRepresentation(WebPageProxy::WebPageProxySessionStateFilterCallback filter, void* context) const
 {
     ASSERT(!m_hasCurrentIndex || m_currentIndex < m_entries.size());

     if (!m_hasCurrentIndex) {
         // We represent having no current index by writing out an empty dictionary (besides the version).
         return createEmptySessionHistoryDictionary();
     }

     RetainPtr<CFMutableArrayRef> entries(AdoptCF, CFArrayCreateMutable(0, m_entries.size(), &kCFTypeArrayCallBacks));

     // We may need to update the current index to account for entries that are filtered by the callback.
     CFIndex currentIndex = m_currentIndex;
     bool hasCurrentIndex = true;

     for (size_t i = 0; i < m_entries.size(); ++i) {
         // If we somehow ended up with a null entry then we should consider the data invalid and not save session history at all.
         ASSERT(m_entries[i]);
         if (!m_entries[i]) {
             LOG(SessionState, "WebBackForwardList contained a null entry at index %lu", i);
             return 0;
         }

         if (filter && !filter(toAPI(m_page), WKPageGetSessionHistoryURLValueType(), toURLRef(m_entries[i]->originalURL().impl()), context)) {
             if (i <= m_currentIndex)
                 currentIndex--;
             continue;
         }

         RetainPtr<CFStringRef> url = m_entries[i]->url().createCFString();
         RetainPtr<CFStringRef> title = m_entries[i]->title().createCFString();
         RetainPtr<CFStringRef> originalURL = m_entries[i]->originalURL().createCFString();

         // FIXME: This uses the CoreIPC data encoding format, which means that whenever we change the CoreIPC encoding we need to bump the CurrentSessionStateDataVersion
         // constant in WebPageProxyCF.cpp. The CoreIPC data format is meant to be an implementation detail, and not something that should be written to disk.
         RetainPtr<CFDataRef> entryData(AdoptCF, CFDataCreate(kCFAllocatorDefault, m_entries[i]->backForwardData().data(), m_entries[i]->backForwardData().size()));

         const void* keys[4] = { SessionHistoryEntryURLKey(), SessionHistoryEntryTitleKey(), SessionHistoryEntryOriginalURLKey(), SessionHistoryEntryDataKey() };
         const void* values[4] = { url.get(), title.get(), originalURL.get(), entryData.get() };

         RetainPtr<CFDictionaryRef> entryDictionary(AdoptCF, CFDictionaryCreate(0, keys, values, 4, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks));
         CFArrayAppendValue(entries.get(), entryDictionary.get());
     }

     ASSERT(currentIndex == -1 || (currentIndex > -1 && currentIndex < CFArrayGetCount(entries.get())));
     if (currentIndex < -1 || currentIndex >= CFArrayGetCount(entries.get())) {
         LOG(SessionState, "Filtering entries to be saved resulted in an inconsistent state that we cannot represent");
         return 0;
     }

     // If we have an index and all items before and including the current item were filtered then currentIndex will be -1.
     // In this case the new current index should point at the first item.
     // It's also possible that all items were filtered so we should represent not having a current index.
     if (currentIndex == -1) {
         if (CFArrayGetCount(entries.get()))
             currentIndex = 0;
         else
             hasCurrentIndex = false;
     }

     if (hasCurrentIndex) {
         RetainPtr<CFNumberRef> currentIndexNumber(AdoptCF, CFNumberCreate(0, kCFNumberCFIndexType, &currentIndex));
         const void* keys[3] = { SessionHistoryVersionKey(), SessionHistoryCurrentIndexKey(), SessionHistoryEntriesKey() };
         const void* values[3] = { SessionHistoryCurrentVersion(), currentIndexNumber.get(), entries.get() };

         return CFDictionaryCreate(0, keys, values, 3, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
     }

     // We represent having no current index by writing out an empty dictionary (besides the version).
     return createEmptySessionHistoryDictionary();
 }

 bool WebBackForwardList::restoreFromCFDictionaryRepresentation(CFDictionaryRef dictionary)
 {
     CFNumberRef cfVersion = (CFNumberRef)CFDictionaryGetValue(dictionary, SessionHistoryVersionKey());
     if (!cfVersion) {
         // v0 session history dictionaries did not contain versioning
         return restoreFromV0CFDictionaryRepresentation(dictionary);
     }

     if (CFGetTypeID(cfVersion) != CFNumberGetTypeID()) {
         LOG(SessionState, "WebBackForwardList dictionary representation contains a version that is not a number");
         return false;
     }

     CFIndex version;
     if (!CFNumberGetValue(cfVersion, kCFNumberCFIndexType, &version)) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a correctly typed current version");
         return false;
     }

     if (version == 1)
         return restoreFromV1CFDictionaryRepresentation(dictionary);

     LOG(SessionState, "WebBackForwardList dictionary representation has an invalid current version (%ld)", version);
     return false;
 }

 bool WebBackForwardList::restoreFromV0CFDictionaryRepresentation(CFDictionaryRef dictionary)
 {
     CFNumberRef cfIndex = (CFNumberRef)CFDictionaryGetValue(dictionary, SessionHistoryCurrentIndexKey());
     if (!cfIndex || CFGetTypeID(cfIndex) != CFNumberGetTypeID()) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid current index");
         return false;
     }

     CFIndex currentCFIndex;
     if (!CFNumberGetValue(cfIndex, kCFNumberCFIndexType, &currentCFIndex)) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a correctly typed current index");
         return false;
     }

     if (currentCFIndex < -1) {
         LOG(SessionState, "WebBackForwardList dictionary representation contains an unexpected negative current index (%ld)", currentCFIndex);
         return false;
     }

     CFArrayRef cfEntries = (CFArrayRef)CFDictionaryGetValue(dictionary, SessionHistoryEntriesKey());
     if (!cfEntries || CFGetTypeID(cfEntries) != CFArrayGetTypeID()) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid list of entries");
         return false;
     }

     CFIndex size = CFArrayGetCount(cfEntries);
     if (size < 0 || currentCFIndex >= size) {
         LOG(SessionState, "WebBackForwardList dictionary representation contains an invalid current index (%ld) for the number of entries (%ld)", currentCFIndex, size);
         return false;
     }

     // Version 0 session history relied on currentIndex == -1 to represent the same thing as not having a current index.
     bool hasCurrentIndex = currentCFIndex != -1;

     if (!hasCurrentIndex && size) {
         LOG(SessionState, "WebBackForwardList dictionary representation says there is no current index, but there is a list of %ld entries", size);
         return false;
     }

     BackForwardListItemVector entries;
     if (!extractBackForwardListEntriesFromArray(cfEntries, entries)) {
         // extractBackForwardListEntriesFromArray has already logged the appropriate error message.
         return false;
     }

     ASSERT(entries.size() == static_cast<unsigned>(size));

     m_hasCurrentIndex = hasCurrentIndex;
     m_currentIndex = m_hasCurrentIndex ? static_cast<uint32_t>(currentCFIndex) : 0;
     m_entries = entries;

     return true;
 }

 bool WebBackForwardList::restoreFromV1CFDictionaryRepresentation(CFDictionaryRef dictionary)
 {
     CFNumberRef cfIndex = (CFNumberRef)CFDictionaryGetValue(dictionary, SessionHistoryCurrentIndexKey());
     if (!cfIndex) {
         // No current index means the dictionary represents an empty session.
         m_hasCurrentIndex = false;
         m_currentIndex = 0;
         m_entries.clear();

         return true;
     }

     if (CFGetTypeID(cfIndex) != CFNumberGetTypeID()) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid current index");
         return false;
     }

     CFIndex currentCFIndex;
     if (!CFNumberGetValue(cfIndex, kCFNumberCFIndexType, &currentCFIndex)) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a correctly typed current index");
         return false;
     }

     if (currentCFIndex < 0) {
         LOG(SessionState, "WebBackForwardList dictionary representation contains an unexpected negative current index (%ld)", currentCFIndex);
         return false;
     }

     CFArrayRef cfEntries = (CFArrayRef)CFDictionaryGetValue(dictionary, SessionHistoryEntriesKey());
     if (!cfEntries || CFGetTypeID(cfEntries) != CFArrayGetTypeID()) {
         LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid list of entries");
         return false;
     }

     CFIndex size = CFArrayGetCount(cfEntries);
     if (currentCFIndex >= size) {
         LOG(SessionState, "WebBackForwardList dictionary representation contains an invalid current index (%ld) for the number of entries (%ld)", currentCFIndex, size);
         return false;
     }

     BackForwardListItemVector entries;
     if (!extractBackForwardListEntriesFromArray(cfEntries, entries)) {
         // extractBackForwardListEntriesFromArray has already logged the appropriate error message.
         return false;
     }

     ASSERT(entries.size() == static_cast<unsigned>(size));

     m_hasCurrentIndex = true;
     m_currentIndex = static_cast<uint32_t>(currentCFIndex);
     m_entries = entries;

     return true;
 }

 static bool extractBackForwardListEntriesFromArray(CFArrayRef cfEntries, BackForwardListItemVector& entries)
 {
     CFIndex size = CFArrayGetCount(cfEntries);

     entries.reserveCapacity(size);
     for (CFIndex i = 0; i < size; ++i) {
         CFDictionaryRef entryDictionary = (CFDictionaryRef)CFArrayGetValueAtIndex(cfEntries, i);
         if (!entryDictionary || CFGetTypeID(entryDictionary) != CFDictionaryGetTypeID()) {
             LOG(SessionState, "WebBackForwardList entry array does not have a valid entry at index %i", (int)i);
             return false;
         }

         CFStringRef entryURL = (CFStringRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryURLKey());
         if (!entryURL || CFGetTypeID(entryURL) != CFStringGetTypeID()) {
             LOG(SessionState, "WebBackForwardList entry at index %i does not have a valid URL", (int)i);
             return false;
         }

         CFStringRef entryTitle = (CFStringRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryTitleKey());
         if (!entryTitle || CFGetTypeID(entryTitle) != CFStringGetTypeID()) {
             LOG(SessionState, "WebBackForwardList entry at index %i does not have a valid title", (int)i);
             return false;
         }

         CFStringRef originalURL = (CFStringRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryOriginalURLKey());
         if (!originalURL || CFGetTypeID(originalURL) != CFStringGetTypeID()) {
             LOG(SessionState, "WebBackForwardList entry at index %i does not have a valid original URL", (int)i);
             return false;
         }

         CFDataRef backForwardData = (CFDataRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryDataKey());
         if (!backForwardData || CFGetTypeID(backForwardData) != CFDataGetTypeID()) {
             LOG(SessionState, "WebBackForwardList entry at index %i does not have back/forward data", (int)i);
             return false;
         }

         entries.append(WebBackForwardListItem::create(originalURL, entryURL, entryTitle, CFDataGetBytePtr(backForwardData), CFDataGetLength(backForwardData), generateWebBackForwardItemID()));
     }

     return true;
 }

 } // namespace WebKit
	/*
	* Copyright (C) 2010, 2011, 2012 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 "config.h"
	#include "WebBackForwardList.h"

	#include "Logging.h"
	#include <wtf/RetainPtr.h>
	#include <CoreFoundation/CoreFoundation.h>

	using namespace WebCore;

	namespace WebKit {

	static uint64_t generateWebBackForwardItemID()
	{
	// These IDs exist in the UIProcess for items created by the UIProcess.
	// The IDs generated here need to never collide with the IDs created in WebBackForwardListProxy in the WebProcess.
	// We accomplish this by starting from 2, and only ever using even ids.
	static uint64_t uniqueHistoryItemID = 0;
	uniqueHistoryItemID += 2;
	return uniqueHistoryItemID;
	}

	static CFIndex currentVersion = 1;
	DEFINE_STATIC_GETTER(CFNumberRef, SessionHistoryCurrentVersion, (CFNumberCreate(0, kCFNumberCFIndexType, &currentVersion)));

	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryVersionKey, (CFSTR("SessionHistoryVersion")));
	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryCurrentIndexKey, (CFSTR("SessionHistoryCurrentIndex")));
	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntriesKey, (CFSTR("SessionHistoryEntries")));
	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryTitleKey, (CFSTR("SessionHistoryEntryTitle")));
	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryURLKey, (CFSTR("SessionHistoryEntryURL")));
	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryOriginalURLKey, (CFSTR("SessionHistoryEntryOriginalURL")));
	DEFINE_STATIC_GETTER(CFStringRef, SessionHistoryEntryDataKey, (CFSTR("SessionHistoryEntryData")));

	static bool extractBackForwardListEntriesFromArray(CFArrayRef, BackForwardListItemVector&);

	static CFDictionaryRef createEmptySessionHistoryDictionary()
	{
	static const void* keys[1] = { SessionHistoryVersionKey() };
	static const void* values[1] = { SessionHistoryCurrentVersion() };

	return CFDictionaryCreate(0, keys, values, 1, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
	}

	CFDictionaryRef WebBackForwardList::createCFDictionaryRepresentation(WebPageProxy::WebPageProxySessionStateFilterCallback filter, void* context) const
	{
	ASSERT(!m_hasCurrentIndex \|\| m_currentIndex < m_entries.size());

	if (!m_hasCurrentIndex) {
	// We represent having no current index by writing out an empty dictionary (besides the version).
	return createEmptySessionHistoryDictionary();
	}

	RetainPtr<CFMutableArrayRef> entries(AdoptCF, CFArrayCreateMutable(0, m_entries.size(), &kCFTypeArrayCallBacks));

	// We may need to update the current index to account for entries that are filtered by the callback.
	CFIndex currentIndex = m_currentIndex;
	bool hasCurrentIndex = true;

	for (size_t i = 0; i < m_entries.size(); ++i) {
	// If we somehow ended up with a null entry then we should consider the data invalid and not save session history at all.
	ASSERT(m_entries[i]);
	if (!m_entries[i]) {
	LOG(SessionState, "WebBackForwardList contained a null entry at index %lu", i);
	return 0;
	}

	if (filter && !filter(toAPI(m_page), WKPageGetSessionHistoryURLValueType(), toURLRef(m_entries[i]->originalURL().impl()), context)) {
	if (i <= m_currentIndex)
	currentIndex--;
	continue;
	}

	RetainPtr<CFStringRef> url = m_entries[i]->url().createCFString();
	RetainPtr<CFStringRef> title = m_entries[i]->title().createCFString();
	RetainPtr<CFStringRef> originalURL = m_entries[i]->originalURL().createCFString();

	// FIXME: This uses the CoreIPC data encoding format, which means that whenever we change the CoreIPC encoding we need to bump the CurrentSessionStateDataVersion
	// constant in WebPageProxyCF.cpp. The CoreIPC data format is meant to be an implementation detail, and not something that should be written to disk.
	RetainPtr<CFDataRef> entryData(AdoptCF, CFDataCreate(kCFAllocatorDefault, m_entries[i]->backForwardData().data(), m_entries[i]->backForwardData().size()));

	const void* keys[4] = { SessionHistoryEntryURLKey(), SessionHistoryEntryTitleKey(), SessionHistoryEntryOriginalURLKey(), SessionHistoryEntryDataKey() };
	const void* values[4] = { url.get(), title.get(), originalURL.get(), entryData.get() };

	RetainPtr<CFDictionaryRef> entryDictionary(AdoptCF, CFDictionaryCreate(0, keys, values, 4, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks));
	CFArrayAppendValue(entries.get(), entryDictionary.get());
	}

	ASSERT(currentIndex == -1 \|\| (currentIndex > -1 && currentIndex < CFArrayGetCount(entries.get())));
	if (currentIndex < -1 \|\| currentIndex >= CFArrayGetCount(entries.get())) {
	LOG(SessionState, "Filtering entries to be saved resulted in an inconsistent state that we cannot represent");
	return 0;
	}

	// If we have an index and all items before and including the current item were filtered then currentIndex will be -1.
	// In this case the new current index should point at the first item.
	// It's also possible that all items were filtered so we should represent not having a current index.
	if (currentIndex == -1) {
	if (CFArrayGetCount(entries.get()))
	currentIndex = 0;
	else
	hasCurrentIndex = false;
	}

	if (hasCurrentIndex) {
	RetainPtr<CFNumberRef> currentIndexNumber(AdoptCF, CFNumberCreate(0, kCFNumberCFIndexType, &currentIndex));
	const void* keys[3] = { SessionHistoryVersionKey(), SessionHistoryCurrentIndexKey(), SessionHistoryEntriesKey() };
	const void* values[3] = { SessionHistoryCurrentVersion(), currentIndexNumber.get(), entries.get() };

	return CFDictionaryCreate(0, keys, values, 3, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
	}

	// We represent having no current index by writing out an empty dictionary (besides the version).
	return createEmptySessionHistoryDictionary();
	}

	bool WebBackForwardList::restoreFromCFDictionaryRepresentation(CFDictionaryRef dictionary)
	{
	CFNumberRef cfVersion = (CFNumberRef)CFDictionaryGetValue(dictionary, SessionHistoryVersionKey());
	if (!cfVersion) {
	// v0 session history dictionaries did not contain versioning
	return restoreFromV0CFDictionaryRepresentation(dictionary);
	}

	if (CFGetTypeID(cfVersion) != CFNumberGetTypeID()) {
	LOG(SessionState, "WebBackForwardList dictionary representation contains a version that is not a number");
	return false;
	}

	CFIndex version;
	if (!CFNumberGetValue(cfVersion, kCFNumberCFIndexType, &version)) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a correctly typed current version");
	return false;
	}

	if (version == 1)
	return restoreFromV1CFDictionaryRepresentation(dictionary);

	LOG(SessionState, "WebBackForwardList dictionary representation has an invalid current version (%ld)", version);
	return false;
	}

	bool WebBackForwardList::restoreFromV0CFDictionaryRepresentation(CFDictionaryRef dictionary)
	{
	CFNumberRef cfIndex = (CFNumberRef)CFDictionaryGetValue(dictionary, SessionHistoryCurrentIndexKey());
	if (!cfIndex \|\| CFGetTypeID(cfIndex) != CFNumberGetTypeID()) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid current index");
	return false;
	}

	CFIndex currentCFIndex;
	if (!CFNumberGetValue(cfIndex, kCFNumberCFIndexType, &currentCFIndex)) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a correctly typed current index");
	return false;
	}

	if (currentCFIndex < -1) {
	LOG(SessionState, "WebBackForwardList dictionary representation contains an unexpected negative current index (%ld)", currentCFIndex);
	return false;
	}

	CFArrayRef cfEntries = (CFArrayRef)CFDictionaryGetValue(dictionary, SessionHistoryEntriesKey());
	if (!cfEntries \|\| CFGetTypeID(cfEntries) != CFArrayGetTypeID()) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid list of entries");
	return false;
	}

	CFIndex size = CFArrayGetCount(cfEntries);
	if (size < 0 \|\| currentCFIndex >= size) {
	LOG(SessionState, "WebBackForwardList dictionary representation contains an invalid current index (%ld) for the number of entries (%ld)", currentCFIndex, size);
	return false;
	}

	// Version 0 session history relied on currentIndex == -1 to represent the same thing as not having a current index.
	bool hasCurrentIndex = currentCFIndex != -1;

	if (!hasCurrentIndex && size) {
	LOG(SessionState, "WebBackForwardList dictionary representation says there is no current index, but there is a list of %ld entries", size);
	return false;
	}

	BackForwardListItemVector entries;
	if (!extractBackForwardListEntriesFromArray(cfEntries, entries)) {
	// extractBackForwardListEntriesFromArray has already logged the appropriate error message.
	return false;
	}

	ASSERT(entries.size() == static_cast<unsigned>(size));

	m_hasCurrentIndex = hasCurrentIndex;
	m_currentIndex = m_hasCurrentIndex ? static_cast<uint32_t>(currentCFIndex) : 0;
	m_entries = entries;

	return true;
	}

	bool WebBackForwardList::restoreFromV1CFDictionaryRepresentation(CFDictionaryRef dictionary)
	{
	CFNumberRef cfIndex = (CFNumberRef)CFDictionaryGetValue(dictionary, SessionHistoryCurrentIndexKey());
	if (!cfIndex) {
	// No current index means the dictionary represents an empty session.
	m_hasCurrentIndex = false;
	m_currentIndex = 0;
	m_entries.clear();

	return true;
	}

	if (CFGetTypeID(cfIndex) != CFNumberGetTypeID()) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid current index");
	return false;
	}

	CFIndex currentCFIndex;
	if (!CFNumberGetValue(cfIndex, kCFNumberCFIndexType, &currentCFIndex)) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a correctly typed current index");
	return false;
	}

	if (currentCFIndex < 0) {
	LOG(SessionState, "WebBackForwardList dictionary representation contains an unexpected negative current index (%ld)", currentCFIndex);
	return false;
	}

	CFArrayRef cfEntries = (CFArrayRef)CFDictionaryGetValue(dictionary, SessionHistoryEntriesKey());
	if (!cfEntries \|\| CFGetTypeID(cfEntries) != CFArrayGetTypeID()) {
	LOG(SessionState, "WebBackForwardList dictionary representation does not have a valid list of entries");
	return false;
	}

	CFIndex size = CFArrayGetCount(cfEntries);
	if (currentCFIndex >= size) {
	LOG(SessionState, "WebBackForwardList dictionary representation contains an invalid current index (%ld) for the number of entries (%ld)", currentCFIndex, size);
	return false;
	}

	BackForwardListItemVector entries;
	if (!extractBackForwardListEntriesFromArray(cfEntries, entries)) {
	// extractBackForwardListEntriesFromArray has already logged the appropriate error message.
	return false;
	}

	ASSERT(entries.size() == static_cast<unsigned>(size));

	m_hasCurrentIndex = true;
	m_currentIndex = static_cast<uint32_t>(currentCFIndex);
	m_entries = entries;

	return true;
	}

	static bool extractBackForwardListEntriesFromArray(CFArrayRef cfEntries, BackForwardListItemVector& entries)
	{
	CFIndex size = CFArrayGetCount(cfEntries);

	entries.reserveCapacity(size);
	for (CFIndex i = 0; i < size; ++i) {
	CFDictionaryRef entryDictionary = (CFDictionaryRef)CFArrayGetValueAtIndex(cfEntries, i);
	if (!entryDictionary \|\| CFGetTypeID(entryDictionary) != CFDictionaryGetTypeID()) {
	LOG(SessionState, "WebBackForwardList entry array does not have a valid entry at index %i", (int)i);
	return false;
	}

	CFStringRef entryURL = (CFStringRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryURLKey());
	if (!entryURL \|\| CFGetTypeID(entryURL) != CFStringGetTypeID()) {
	LOG(SessionState, "WebBackForwardList entry at index %i does not have a valid URL", (int)i);
	return false;
	}

	CFStringRef entryTitle = (CFStringRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryTitleKey());
	if (!entryTitle \|\| CFGetTypeID(entryTitle) != CFStringGetTypeID()) {
	LOG(SessionState, "WebBackForwardList entry at index %i does not have a valid title", (int)i);
	return false;
	}

	CFStringRef originalURL = (CFStringRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryOriginalURLKey());
	if (!originalURL \|\| CFGetTypeID(originalURL) != CFStringGetTypeID()) {
	LOG(SessionState, "WebBackForwardList entry at index %i does not have a valid original URL", (int)i);
	return false;
	}

	CFDataRef backForwardData = (CFDataRef)CFDictionaryGetValue(entryDictionary, SessionHistoryEntryDataKey());
	if (!backForwardData \|\| CFGetTypeID(backForwardData) != CFDataGetTypeID()) {
	LOG(SessionState, "WebBackForwardList entry at index %i does not have back/forward data", (int)i);
	return false;
	}

	entries.append(WebBackForwardListItem::create(originalURL, entryURL, entryTitle, CFDataGetBytePtr(backForwardData), CFDataGetLength(backForwardData), generateWebBackForwardItemID()));
	}

	return true;
	}

	} // namespace WebKit