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/*
* Copyright (C) 2008 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. ``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
* 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 "StorageMap.h"
#include <wtf/TemporaryChange.h>
namespace WebCore {
PassRefPtr<StorageMap> StorageMap::create(unsigned quota)
{
return adoptRef(new StorageMap(quota));
}
StorageMap::StorageMap(unsigned quota)
: m_iterator(m_map.end())
, m_iteratorIndex(UINT_MAX)
, m_quotaSize(quota) // quota measured in bytes
, m_currentLength(0)
{
}
PassRefPtr<StorageMap> StorageMap::copy()
{
RefPtr<StorageMap> newMap = create(m_quotaSize);
newMap->m_map = m_map;
newMap->m_currentLength = m_currentLength;
return newMap.release();
}
void StorageMap::invalidateIterator()
{
m_iterator = m_map.end();
m_iteratorIndex = UINT_MAX;
}
void StorageMap::setIteratorToIndex(unsigned index)
{
// FIXME: Once we have bidirectional iterators for HashMap we can be more intelligent about this.
// The requested index will be closest to begin(), our current iterator, or end(), and we
// can take the shortest route.
// Until that mechanism is available, we'll always increment our iterator from begin() or current.
if (m_iteratorIndex == index)
return;
if (index < m_iteratorIndex) {
m_iteratorIndex = 0;
m_iterator = m_map.begin();
ASSERT(m_iterator != m_map.end());
}
while (m_iteratorIndex < index) {
++m_iteratorIndex;
++m_iterator;
ASSERT(m_iterator != m_map.end());
}
}
unsigned StorageMap::length() const
{
return m_map.size();
}
String StorageMap::key(unsigned index)
{
if (index >= length())
return String();
setIteratorToIndex(index);
return m_iterator->key;
}
String StorageMap::getItem(const String& key) const
{
return m_map.get(key);
}
PassRefPtr<StorageMap> StorageMap::setItem(const String& key, const String& value, String& oldValue, bool& quotaException)
{
ASSERT(!value.isNull());
quotaException = false;
// Implement copy-on-write semantics here. We're guaranteed that the only refs of StorageMaps belong to Storage objects
// so if more than one Storage object refs this map, copy it before mutating it.
if (refCount() > 1) {
RefPtr<StorageMap> newStorageMap = copy();
newStorageMap->setItem(key, value, oldValue, quotaException);
return newStorageMap.release();
}
// Quota tracking. This is done in a couple of steps to keep the overflow tracking simple.
unsigned newLength = m_currentLength;
bool overflow = newLength + value.length() < newLength;
newLength += value.length();
oldValue = m_map.get(key);
overflow |= newLength - oldValue.length() > newLength;
newLength -= oldValue.length();
unsigned adjustedKeyLength = oldValue.isNull() ? key.length() : 0;
overflow |= newLength + adjustedKeyLength < newLength;
newLength += adjustedKeyLength;
ASSERT(!overflow); // Overflow is bad...even if quotas are off.
bool overQuota = newLength > m_quotaSize / sizeof(UChar);
if (m_quotaSize != noQuota && (overflow || overQuota)) {
quotaException = true;
return 0;
}
m_currentLength = newLength;
HashMap<String, String>::AddResult addResult = m_map.add(key, value);
if (!addResult.isNewEntry)
addResult.iterator->value = value;
invalidateIterator();
return 0;
}
PassRefPtr<StorageMap> StorageMap::setItemIgnoringQuota(const String& key, const String& value)
{
TemporaryChange<unsigned> quotaSizeChange(m_quotaSize, noQuota);
String oldValue;
bool quotaException;
RefPtr<StorageMap> map = setItem(key, value, oldValue, quotaException);
ASSERT(!quotaException);
return map.release();
}
PassRefPtr<StorageMap> StorageMap::removeItem(const String& key, String& oldValue)
{
// Implement copy-on-write semantics here. We're guaranteed that the only refs of StorageMaps belong to Storage objects
// so if more than one Storage object refs this map, copy it before mutating it.
if (refCount() > 1) {
RefPtr<StorageMap> newStorage = copy();
newStorage->removeItem(key, oldValue);
return newStorage.release();
}
oldValue = m_map.take(key);
if (!oldValue.isNull()) {
invalidateIterator();
ASSERT(m_currentLength - key.length() <= m_currentLength);
m_currentLength -= key.length();
}
ASSERT(m_currentLength - oldValue.length() <= m_currentLength);
m_currentLength -= oldValue.length();
return 0;
}
bool StorageMap::contains(const String& key) const
{
return m_map.contains(key);
}
void StorageMap::importItems(const HashMap<String, String>& items)
{
for (HashMap<String, String>::const_iterator it = items.begin(), end = items.end(); it != end; ++it) {
const String& key = it->key;
const String& value = it->value;
HashMap<String, String>::AddResult result = m_map.add(key, value);
ASSERT_UNUSED(result, result.isNewEntry); // True if the key didn't exist previously.
ASSERT(m_currentLength + key.length() >= m_currentLength);
m_currentLength += key.length();
ASSERT(m_currentLength + value.length() >= m_currentLength);
m_currentLength += value.length();
}
}
}
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