Source/WebKit2/WebProcess/Storage/StorageAreaMap.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2013 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 "StorageAreaMap.h"

 #include "StorageAreaImpl.h"
 #include "StorageAreaMapMessages.h"
 #include "StorageManagerMessages.h"
 #include "StorageNamespaceImpl.h"
 #include "WebPage.h"
 #include "WebPageGroupProxy.h"
 #include "WebProcess.h"
 #include <WebCore/DOMWindow.h>
 #include <WebCore/Document.h>
 #include <WebCore/MainFrame.h>
 #include <WebCore/Page.h>
 #include <WebCore/PageGroup.h>
 #include <WebCore/SecurityOriginData.h>
 #include <WebCore/Storage.h>
 #include <WebCore/StorageEventDispatcher.h>
 #include <WebCore/StorageMap.h>
 #include <WebCore/StorageType.h>

 using namespace WebCore;

 namespace WebKit {

 static uint64_t generateStorageMapID()
 {
     static uint64_t storageMapID;
     return ++storageMapID;
 }

 Ref<StorageAreaMap> StorageAreaMap::create(StorageNamespaceImpl* storageNamespace, Ref<WebCore::SecurityOrigin>&& securityOrigin)
 {
     return adoptRef(*new StorageAreaMap(storageNamespace, WTFMove(securityOrigin)));
 }

 StorageAreaMap::StorageAreaMap(StorageNamespaceImpl* storageNamespace, Ref<WebCore::SecurityOrigin>&& securityOrigin)
     : m_storageNamespace(*storageNamespace)
     , m_storageMapID(generateStorageMapID())
     , m_storageType(storageNamespace->storageType())
     , m_storageNamespaceID(storageNamespace->storageNamespaceID())
     , m_quotaInBytes(storageNamespace->quotaInBytes())
     , m_securityOrigin(WTFMove(securityOrigin))
     , m_currentSeed(0)
     , m_hasPendingClear(false)
     , m_hasPendingGetValues(false)
 {
     switch (m_storageType) {
     case StorageType::Local:
     case StorageType::TransientLocal:
         if (SecurityOrigin* topLevelOrigin = storageNamespace->topLevelOrigin())
             WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::CreateTransientLocalStorageMap(m_storageMapID, storageNamespace->storageNamespaceID(), SecurityOriginData::fromSecurityOrigin(*topLevelOrigin), SecurityOriginData::fromSecurityOrigin(m_securityOrigin)), 0);
         else
             WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::CreateLocalStorageMap(m_storageMapID, storageNamespace->storageNamespaceID(), SecurityOriginData::fromSecurityOrigin(m_securityOrigin)), 0);

         break;

     case StorageType::Session:
         WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::CreateSessionStorageMap(m_storageMapID, storageNamespace->storageNamespaceID(), SecurityOriginData::fromSecurityOrigin(m_securityOrigin)), 0);
         break;

     case StorageType::EphemeralLocal:
         // The UI process is not involved for EphemeralLocal storages.
         return;
     }

     WebProcess::singleton().addMessageReceiver(Messages::StorageAreaMap::messageReceiverName(), m_storageMapID, *this);
 }

 StorageAreaMap::~StorageAreaMap()
 {
     if (m_storageType != StorageType::EphemeralLocal) {
         WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::DestroyStorageMap(m_storageMapID), 0);
         WebProcess::singleton().removeMessageReceiver(Messages::StorageAreaMap::messageReceiverName(), m_storageMapID);
     }

     m_storageNamespace->didDestroyStorageAreaMap(*this);
 }

 unsigned StorageAreaMap::length()
 {
     loadValuesIfNeeded();

     return m_storageMap->length();
 }

 String StorageAreaMap::key(unsigned index)
 {
     loadValuesIfNeeded();

     return m_storageMap->key(index);
 }

 String StorageAreaMap::item(const String& key)
 {
     loadValuesIfNeeded();

     return m_storageMap->getItem(key);
 }

 void StorageAreaMap::setItem(Frame* sourceFrame, StorageAreaImpl* sourceArea, const String& key, const String& value, bool& quotaException)
 {
     loadValuesIfNeeded();

     ASSERT(m_storageMap->hasOneRef());

     String oldValue;
     quotaException = false;
     m_storageMap->setItem(key, value, oldValue, quotaException);
     if (quotaException)
         return;

     if (oldValue == value)
         return;

     m_pendingValueChanges.add(key);

     WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::SetItem(m_storageMapID, sourceArea->storageAreaID(), m_currentSeed, key, value, sourceFrame->document()->url()), 0);
 }

 void StorageAreaMap::removeItem(WebCore::Frame* sourceFrame, StorageAreaImpl* sourceArea, const String& key)
 {
     loadValuesIfNeeded();
     ASSERT(m_storageMap->hasOneRef());

     String oldValue;
     m_storageMap->removeItem(key, oldValue);

     if (oldValue.isNull())
         return;

     m_pendingValueChanges.add(key);

     WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::RemoveItem(m_storageMapID, sourceArea->storageAreaID(), m_currentSeed, key, sourceFrame->document()->url()), 0);
 }

 void StorageAreaMap::clear(WebCore::Frame* sourceFrame, StorageAreaImpl* sourceArea)
 {
     resetValues();

     m_hasPendingClear = true;
     m_storageMap = StorageMap::create(m_quotaInBytes);
     WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::Clear(m_storageMapID, sourceArea->storageAreaID(), m_currentSeed, sourceFrame->document()->url()), 0);
 }

 bool StorageAreaMap::contains(const String& key)
 {
     loadValuesIfNeeded();

     return m_storageMap->contains(key);
 }

 void StorageAreaMap::resetValues()
 {
     m_storageMap = nullptr;

     m_pendingValueChanges.clear();
     m_hasPendingClear = false;
     m_hasPendingGetValues = false;
     m_currentSeed++;
 }

 void StorageAreaMap::loadValuesIfNeeded()
 {
     if (m_storageMap)
         return;

     HashMap<String, String> values;
     // FIXME: This should use a special sendSync flag to indicate that we don't want to process incoming messages while waiting for a reply.
     // (This flag does not yet exist). Since loadValuesIfNeeded() ends up being called from within JavaScript code, processing incoming synchronous messages
     // could lead to weird reentrency bugs otherwise.
     WebProcess::singleton().parentProcessConnection()->sendSync(Messages::StorageManager::GetValues(m_storageMapID, m_currentSeed), Messages::StorageManager::GetValues::Reply(values), 0);

     m_storageMap = StorageMap::create(m_quotaInBytes);
     m_storageMap->importItems(values);

     // We want to ignore all changes until we get the DidGetValues message.
     m_hasPendingGetValues = true;
 }

 void StorageAreaMap::didGetValues(uint64_t storageMapSeed)
 {
     if (m_currentSeed != storageMapSeed)
         return;

     ASSERT(m_hasPendingGetValues);
     m_hasPendingGetValues = false;
 }

 void StorageAreaMap::didSetItem(uint64_t storageMapSeed, const String& key, bool quotaError)
 {
     if (m_currentSeed != storageMapSeed)
         return;

     ASSERT(m_pendingValueChanges.contains(key));

     if (quotaError) {
         resetValues();
         return;
     }

     m_pendingValueChanges.remove(key);
 }

 void StorageAreaMap::didRemoveItem(uint64_t storageMapSeed, const String& key)
 {
     if (m_currentSeed != storageMapSeed)
         return;

     ASSERT(m_pendingValueChanges.contains(key));
     m_pendingValueChanges.remove(key);
 }

 void StorageAreaMap::didClear(uint64_t storageMapSeed)
 {
     if (m_currentSeed != storageMapSeed)
         return;

     ASSERT(m_hasPendingClear);
     m_hasPendingClear = false;
 }

 bool StorageAreaMap::shouldApplyChangeForKey(const String& key) const
 {
     // We have not yet loaded anything from this storage map.
     if (!m_storageMap)
         return false;

     // Check if this storage area is currently waiting for the storage manager to update the given key.
     // If that is the case, we don't want to apply any changes made by other storage areas, since
     // our change was made last.
     if (m_pendingValueChanges.contains(key))
         return false;

     return true;
 }

 void StorageAreaMap::applyChange(const String& key, const String& newValue)
 {
     ASSERT(!m_storageMap || m_storageMap->hasOneRef());

     // There's a clear pending or getValues pending we don't want to apply any changes until we get the corresponding DidClear/DidGetValues messages.
     if (m_hasPendingClear || m_hasPendingGetValues)
         return;

     if (!key) {
         // A null key means clear.
         auto newStorageMap = StorageMap::create(m_quotaInBytes);

         // Any changes that were made locally after the clear must still be kept around in the new map.
         for (auto it = m_pendingValueChanges.begin().keys(), end = m_pendingValueChanges.end().keys(); it != end; ++it) {
             const String& key = *it;

             String value = m_storageMap->getItem(key);
             if (!value) {
                 // This change must have been a pending remove, ignore it.
                 continue;
             }

             String oldValue;
             newStorageMap->setItemIgnoringQuota(key, oldValue);
         }

         m_storageMap = WTFMove(newStorageMap);
         return;
     }

     if (!shouldApplyChangeForKey(key))
         return;

     if (!newValue) {
         // A null new value means that the item should be removed.
         String oldValue;
         m_storageMap->removeItem(key, oldValue);
         return;
     }

     m_storageMap->setItemIgnoringQuota(key, newValue);
 }

 void StorageAreaMap::dispatchStorageEvent(uint64_t sourceStorageAreaID, const String& key, const String& oldValue, const String& newValue, const String& urlString)
 {
     if (!sourceStorageAreaID) {
         // This storage event originates from another process so we need to apply the change to our storage area map.
         applyChange(key, newValue);
     }

     if (storageType() == StorageType::Session)
         dispatchSessionStorageEvent(sourceStorageAreaID, key, oldValue, newValue, urlString);
     else
         dispatchLocalStorageEvent(sourceStorageAreaID, key, oldValue, newValue, urlString);
 }

 void StorageAreaMap::clearCache()
 {
     resetValues();
 }

 void StorageAreaMap::dispatchSessionStorageEvent(uint64_t sourceStorageAreaID, const String& key, const String& oldValue, const String& newValue, const String& urlString)
 {
     ASSERT(storageType() == StorageType::Session);

     // Namespace IDs for session storage namespaces are equivalent to web page IDs
     // so we can get the right page here.
     WebPage* webPage = WebProcess::singleton().webPage(m_storageNamespaceID);
     if (!webPage)
         return;

     Vector<RefPtr<Frame>> frames;

     Page* page = webPage->corePage();
     for (Frame* frame = &page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
         Document* document = frame->document();
         if (!document->securityOrigin().equal(m_securityOrigin.ptr()))
             continue;

         Storage* storage = document->domWindow()->optionalSessionStorage();
         if (!storage)
             continue;

         StorageAreaImpl& storageArea = static_cast<StorageAreaImpl&>(storage->area());
         if (storageArea.storageAreaID() == sourceStorageAreaID) {
             // This is the storage area that caused the event to be dispatched.
             continue;
         }

         frames.append(frame);
     }

     StorageEventDispatcher::dispatchSessionStorageEventsToFrames(*page, frames, key, oldValue, newValue, urlString, SecurityOriginData::fromSecurityOrigin(m_securityOrigin));
 }

 void StorageAreaMap::dispatchLocalStorageEvent(uint64_t sourceStorageAreaID, const String& key, const String& oldValue, const String& newValue, const String& urlString)
 {
     ASSERT(isLocalStorage(storageType()));

     Vector<RefPtr<Frame>> frames;

     PageGroup& pageGroup = *WebProcess::singleton().webPageGroup(m_storageNamespaceID)->corePageGroup();
     const HashSet<Page*>& pages = pageGroup.pages();
     for (HashSet<Page*>::const_iterator it = pages.begin(), end = pages.end(); it != end; ++it) {
         for (Frame* frame = &(*it)->mainFrame(); frame; frame = frame->tree().traverseNext()) {
             Document* document = frame->document();
             if (!document->securityOrigin().equal(m_securityOrigin.ptr()))
                 continue;

             Storage* storage = document->domWindow()->optionalLocalStorage();
             if (!storage)
                 continue;

             StorageAreaImpl& storageArea = static_cast<StorageAreaImpl&>(storage->area());
             if (storageArea.storageAreaID() == sourceStorageAreaID) {
                 // This is the storage area that caused the event to be dispatched.
                 continue;
             }

             frames.append(frame);
         }
     }

     StorageEventDispatcher::dispatchLocalStorageEventsToFrames(pageGroup, frames, key, oldValue, newValue, urlString, SecurityOriginData::fromSecurityOrigin(m_securityOrigin));
 }

 } // namespace WebKit
	/*
	* Copyright (C) 2013 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 "StorageAreaMap.h"

	#include "StorageAreaImpl.h"
	#include "StorageAreaMapMessages.h"
	#include "StorageManagerMessages.h"
	#include "StorageNamespaceImpl.h"
	#include "WebPage.h"
	#include "WebPageGroupProxy.h"
	#include "WebProcess.h"
	#include <WebCore/DOMWindow.h>
	#include <WebCore/Document.h>
	#include <WebCore/MainFrame.h>
	#include <WebCore/Page.h>
	#include <WebCore/PageGroup.h>
	#include <WebCore/SecurityOriginData.h>
	#include <WebCore/Storage.h>
	#include <WebCore/StorageEventDispatcher.h>
	#include <WebCore/StorageMap.h>
	#include <WebCore/StorageType.h>

	using namespace WebCore;

	namespace WebKit {

	static uint64_t generateStorageMapID()
	{
	static uint64_t storageMapID;
	return ++storageMapID;
	}

	Ref<StorageAreaMap> StorageAreaMap::create(StorageNamespaceImpl* storageNamespace, Ref<WebCore::SecurityOrigin>&& securityOrigin)
	{
	return adoptRef(*new StorageAreaMap(storageNamespace, WTFMove(securityOrigin)));
	}

	StorageAreaMap::StorageAreaMap(StorageNamespaceImpl* storageNamespace, Ref<WebCore::SecurityOrigin>&& securityOrigin)
	: m_storageNamespace(*storageNamespace)
	, m_storageMapID(generateStorageMapID())
	, m_storageType(storageNamespace->storageType())
	, m_storageNamespaceID(storageNamespace->storageNamespaceID())
	, m_quotaInBytes(storageNamespace->quotaInBytes())
	, m_securityOrigin(WTFMove(securityOrigin))
	, m_currentSeed(0)
	, m_hasPendingClear(false)
	, m_hasPendingGetValues(false)
	{
	switch (m_storageType) {
	case StorageType::Local:
	case StorageType::TransientLocal:
	if (SecurityOrigin* topLevelOrigin = storageNamespace->topLevelOrigin())
	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::CreateTransientLocalStorageMap(m_storageMapID, storageNamespace->storageNamespaceID(), SecurityOriginData::fromSecurityOrigin(*topLevelOrigin), SecurityOriginData::fromSecurityOrigin(m_securityOrigin)), 0);
	else
	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::CreateLocalStorageMap(m_storageMapID, storageNamespace->storageNamespaceID(), SecurityOriginData::fromSecurityOrigin(m_securityOrigin)), 0);

	break;

	case StorageType::Session:
	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::CreateSessionStorageMap(m_storageMapID, storageNamespace->storageNamespaceID(), SecurityOriginData::fromSecurityOrigin(m_securityOrigin)), 0);
	break;

	case StorageType::EphemeralLocal:
	// The UI process is not involved for EphemeralLocal storages.
	return;
	}

	WebProcess::singleton().addMessageReceiver(Messages::StorageAreaMap::messageReceiverName(), m_storageMapID, *this);
	}

	StorageAreaMap::~StorageAreaMap()
	{
	if (m_storageType != StorageType::EphemeralLocal) {
	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::DestroyStorageMap(m_storageMapID), 0);
	WebProcess::singleton().removeMessageReceiver(Messages::StorageAreaMap::messageReceiverName(), m_storageMapID);
	}

	m_storageNamespace->didDestroyStorageAreaMap(*this);
	}

	unsigned StorageAreaMap::length()
	{
	loadValuesIfNeeded();

	return m_storageMap->length();
	}

	String StorageAreaMap::key(unsigned index)
	{
	loadValuesIfNeeded();

	return m_storageMap->key(index);
	}

	String StorageAreaMap::item(const String& key)
	{
	loadValuesIfNeeded();

	return m_storageMap->getItem(key);
	}

	void StorageAreaMap::setItem(Frame* sourceFrame, StorageAreaImpl* sourceArea, const String& key, const String& value, bool& quotaException)
	{
	loadValuesIfNeeded();

	ASSERT(m_storageMap->hasOneRef());

	String oldValue;
	quotaException = false;
	m_storageMap->setItem(key, value, oldValue, quotaException);
	if (quotaException)
	return;

	if (oldValue == value)
	return;

	m_pendingValueChanges.add(key);

	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::SetItem(m_storageMapID, sourceArea->storageAreaID(), m_currentSeed, key, value, sourceFrame->document()->url()), 0);
	}

	void StorageAreaMap::removeItem(WebCore::Frame* sourceFrame, StorageAreaImpl* sourceArea, const String& key)
	{
	loadValuesIfNeeded();
	ASSERT(m_storageMap->hasOneRef());

	String oldValue;
	m_storageMap->removeItem(key, oldValue);

	if (oldValue.isNull())
	return;

	m_pendingValueChanges.add(key);

	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::RemoveItem(m_storageMapID, sourceArea->storageAreaID(), m_currentSeed, key, sourceFrame->document()->url()), 0);
	}

	void StorageAreaMap::clear(WebCore::Frame* sourceFrame, StorageAreaImpl* sourceArea)
	{
	resetValues();

	m_hasPendingClear = true;
	m_storageMap = StorageMap::create(m_quotaInBytes);
	WebProcess::singleton().parentProcessConnection()->send(Messages::StorageManager::Clear(m_storageMapID, sourceArea->storageAreaID(), m_currentSeed, sourceFrame->document()->url()), 0);
	}

	bool StorageAreaMap::contains(const String& key)
	{
	loadValuesIfNeeded();

	return m_storageMap->contains(key);
	}

	void StorageAreaMap::resetValues()
	{
	m_storageMap = nullptr;

	m_pendingValueChanges.clear();
	m_hasPendingClear = false;
	m_hasPendingGetValues = false;
	m_currentSeed++;
	}

	void StorageAreaMap::loadValuesIfNeeded()
	{
	if (m_storageMap)
	return;

	HashMap<String, String> values;
	// FIXME: This should use a special sendSync flag to indicate that we don't want to process incoming messages while waiting for a reply.
	// (This flag does not yet exist). Since loadValuesIfNeeded() ends up being called from within JavaScript code, processing incoming synchronous messages
	// could lead to weird reentrency bugs otherwise.
	WebProcess::singleton().parentProcessConnection()->sendSync(Messages::StorageManager::GetValues(m_storageMapID, m_currentSeed), Messages::StorageManager::GetValues::Reply(values), 0);

	m_storageMap = StorageMap::create(m_quotaInBytes);
	m_storageMap->importItems(values);

	// We want to ignore all changes until we get the DidGetValues message.
	m_hasPendingGetValues = true;
	}

	void StorageAreaMap::didGetValues(uint64_t storageMapSeed)
	{
	if (m_currentSeed != storageMapSeed)
	return;

	ASSERT(m_hasPendingGetValues);
	m_hasPendingGetValues = false;
	}

	void StorageAreaMap::didSetItem(uint64_t storageMapSeed, const String& key, bool quotaError)
	{
	if (m_currentSeed != storageMapSeed)
	return;

	ASSERT(m_pendingValueChanges.contains(key));

	if (quotaError) {
	resetValues();
	return;
	}

	m_pendingValueChanges.remove(key);
	}

	void StorageAreaMap::didRemoveItem(uint64_t storageMapSeed, const String& key)
	{
	if (m_currentSeed != storageMapSeed)
	return;

	ASSERT(m_pendingValueChanges.contains(key));
	m_pendingValueChanges.remove(key);
	}

	void StorageAreaMap::didClear(uint64_t storageMapSeed)
	{
	if (m_currentSeed != storageMapSeed)
	return;

	ASSERT(m_hasPendingClear);
	m_hasPendingClear = false;
	}

	bool StorageAreaMap::shouldApplyChangeForKey(const String& key) const
	{
	// We have not yet loaded anything from this storage map.
	if (!m_storageMap)
	return false;

	// Check if this storage area is currently waiting for the storage manager to update the given key.
	// If that is the case, we don't want to apply any changes made by other storage areas, since
	// our change was made last.
	if (m_pendingValueChanges.contains(key))
	return false;

	return true;
	}

	void StorageAreaMap::applyChange(const String& key, const String& newValue)
	{
	ASSERT(!m_storageMap \|\| m_storageMap->hasOneRef());

	// There's a clear pending or getValues pending we don't want to apply any changes until we get the corresponding DidClear/DidGetValues messages.
	if (m_hasPendingClear \|\| m_hasPendingGetValues)
	return;

	if (!key) {
	// A null key means clear.
	auto newStorageMap = StorageMap::create(m_quotaInBytes);

	// Any changes that were made locally after the clear must still be kept around in the new map.
	for (auto it = m_pendingValueChanges.begin().keys(), end = m_pendingValueChanges.end().keys(); it != end; ++it) {
	const String& key = *it;

	String value = m_storageMap->getItem(key);
	if (!value) {
	// This change must have been a pending remove, ignore it.
	continue;
	}

	String oldValue;
	newStorageMap->setItemIgnoringQuota(key, oldValue);
	}

	m_storageMap = WTFMove(newStorageMap);
	return;
	}

	if (!shouldApplyChangeForKey(key))
	return;

	if (!newValue) {
	// A null new value means that the item should be removed.
	String oldValue;
	m_storageMap->removeItem(key, oldValue);
	return;
	}

	m_storageMap->setItemIgnoringQuota(key, newValue);
	}

	void StorageAreaMap::dispatchStorageEvent(uint64_t sourceStorageAreaID, const String& key, const String& oldValue, const String& newValue, const String& urlString)
	{
	if (!sourceStorageAreaID) {
	// This storage event originates from another process so we need to apply the change to our storage area map.
	applyChange(key, newValue);
	}

	if (storageType() == StorageType::Session)
	dispatchSessionStorageEvent(sourceStorageAreaID, key, oldValue, newValue, urlString);
	else
	dispatchLocalStorageEvent(sourceStorageAreaID, key, oldValue, newValue, urlString);
	}

	void StorageAreaMap::clearCache()
	{
	resetValues();
	}

	void StorageAreaMap::dispatchSessionStorageEvent(uint64_t sourceStorageAreaID, const String& key, const String& oldValue, const String& newValue, const String& urlString)
	{
	ASSERT(storageType() == StorageType::Session);

	// Namespace IDs for session storage namespaces are equivalent to web page IDs
	// so we can get the right page here.
	WebPage* webPage = WebProcess::singleton().webPage(m_storageNamespaceID);
	if (!webPage)
	return;

	Vector<RefPtr<Frame>> frames;

	Page* page = webPage->corePage();
	for (Frame* frame = &page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
	Document* document = frame->document();
	if (!document->securityOrigin().equal(m_securityOrigin.ptr()))
	continue;

	Storage* storage = document->domWindow()->optionalSessionStorage();
	if (!storage)
	continue;

	StorageAreaImpl& storageArea = static_cast<StorageAreaImpl&>(storage->area());
	if (storageArea.storageAreaID() == sourceStorageAreaID) {
	// This is the storage area that caused the event to be dispatched.
	continue;
	}

	frames.append(frame);
	}

	StorageEventDispatcher::dispatchSessionStorageEventsToFrames(*page, frames, key, oldValue, newValue, urlString, SecurityOriginData::fromSecurityOrigin(m_securityOrigin));
	}

	void StorageAreaMap::dispatchLocalStorageEvent(uint64_t sourceStorageAreaID, const String& key, const String& oldValue, const String& newValue, const String& urlString)
	{
	ASSERT(isLocalStorage(storageType()));

	Vector<RefPtr<Frame>> frames;

	PageGroup& pageGroup = *WebProcess::singleton().webPageGroup(m_storageNamespaceID)->corePageGroup();
	const HashSet<Page*>& pages = pageGroup.pages();
	for (HashSet<Page*>::const_iterator it = pages.begin(), end = pages.end(); it != end; ++it) {
	for (Frame* frame = &(*it)->mainFrame(); frame; frame = frame->tree().traverseNext()) {
	Document* document = frame->document();
	if (!document->securityOrigin().equal(m_securityOrigin.ptr()))
	continue;

	Storage* storage = document->domWindow()->optionalLocalStorage();
	if (!storage)
	continue;

	StorageAreaImpl& storageArea = static_cast<StorageAreaImpl&>(storage->area());
	if (storageArea.storageAreaID() == sourceStorageAreaID) {
	// This is the storage area that caused the event to be dispatched.
	continue;
	}

	frames.append(frame);
	}
	}

	StorageEventDispatcher::dispatchLocalStorageEventsToFrames(pageGroup, frames, key, oldValue, newValue, urlString, SecurityOriginData::fromSecurityOrigin(m_securityOrigin));
	}

	} // namespace WebKit