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/*
* Copyright (C) 2013, 2015 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 "WeakMapData.h"
#include "CopiedAllocator.h"
#include "CopyVisitorInlines.h"
#include "ExceptionHelpers.h"
#include "JSCJSValueInlines.h"
#include "SlotVisitorInlines.h"
#include <wtf/MathExtras.h>
namespace JSC {
const ClassInfo WeakMapData::s_info = { "WeakMapData", 0, 0, CREATE_METHOD_TABLE(WeakMapData) };
WeakMapData::WeakMapData(VM& vm)
: Base(vm, vm.weakMapDataStructure.get())
, m_deadKeyCleaner(this)
{
}
void WeakMapData::finishCreation(VM& vm)
{
Base::finishCreation(vm);
}
void WeakMapData::destroy(JSCell* cell)
{
static_cast<WeakMapData*>(cell)->~WeakMapData();
}
size_t WeakMapData::estimatedSize(JSCell* cell)
{
WeakMapData* thisObj = jsCast<WeakMapData*>(cell);
return Base::estimatedSize(cell) + (thisObj->m_map.capacity() * (sizeof(JSObject*) + sizeof(WriteBarrier<Unknown>)));
}
void WeakMapData::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
Base::visitChildren(cell, visitor);
WeakMapData* thisObj = jsCast<WeakMapData*>(cell);
visitor.addUnconditionalFinalizer(&thisObj->m_deadKeyCleaner);
visitor.addWeakReferenceHarvester(&thisObj->m_deadKeyCleaner);
// Rough approximation of the external storage needed for the hashtable.
// This isn't exact, but it is close enough, and proportional to the actual
// external memory usage.
visitor.reportExtraMemoryVisited(thisObj->m_map.capacity() * (sizeof(JSObject*) + sizeof(WriteBarrier<Unknown>)));
}
void WeakMapData::set(VM& vm, JSObject* key, JSValue value)
{
// Here we force the write barrier on the key.
auto result = m_map.add(WriteBarrier<JSObject>(vm, this, key).get(), WriteBarrier<Unknown>());
result.iterator->value.set(vm, this, value);
}
JSValue WeakMapData::get(JSObject* key)
{
auto iter = m_map.find(key);
if (iter == m_map.end())
return jsUndefined();
return iter->value.get();
}
bool WeakMapData::remove(JSObject* key)
{
auto iter = m_map.find(key);
if (iter == m_map.end())
return false;
m_map.remove(iter);
return true;
}
bool WeakMapData::contains(JSObject* key)
{
return m_map.contains(key);
}
void WeakMapData::clear()
{
m_map.clear();
}
void WeakMapData::DeadKeyCleaner::visitWeakReferences(SlotVisitor& visitor)
{
m_liveKeyCount = 0;
for (auto it = m_target->m_map.begin(), end = m_target->m_map.end(); it != end; ++it) {
if (!Heap::isMarked(it->key))
continue;
m_liveKeyCount++;
visitor.append(&it->value);
}
RELEASE_ASSERT(m_liveKeyCount <= m_target->m_map.size());
}
void WeakMapData::DeadKeyCleaner::finalizeUnconditionally()
{
if (m_liveKeyCount > m_target->m_map.size() / 2) {
RELEASE_ASSERT(m_liveKeyCount <= m_target->m_map.size());
int deadCount = m_target->m_map.size() - m_liveKeyCount;
if (!deadCount)
return;
Vector<JSObject*> deadEntries;
deadEntries.reserveCapacity(deadCount);
for (auto it = m_target->m_map.begin(), end = m_target->m_map.end(); it != end; ++it) {
if (Heap::isMarked(it->key))
continue;
deadEntries.uncheckedAppend(it->key);
}
for (size_t i = 0; i < deadEntries.size(); i++)
m_target->m_map.remove(deadEntries[i]);
} else {
MapType newMap;
for (auto it = m_target->m_map.begin(), end = m_target->m_map.end(); it != end; ++it) {
if (!Heap::isMarked(it->key))
continue;
newMap.add(it->key, it->value);
}
m_target->m_map.swap(newMap);
}
}
}
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