darling-JavaScriptCore/heap/WeakSet.cpp

127 lines
3.8 KiB
C++

/*
* Copyright (C) 2012, 2016 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 "WeakSet.h"
#include "Heap.h"
#include "VM.h"
namespace JSC {
WeakSet::~WeakSet()
{
if (isOnList())
remove();
Heap& heap = *this->heap();
WeakBlock* next = nullptr;
for (WeakBlock* block = m_blocks.head(); block; block = next) {
next = block->next();
WeakBlock::destroy(heap, block);
}
m_blocks.clear();
}
void WeakSet::sweep()
{
for (WeakBlock* block = m_blocks.head(); block;) {
heap()->sweepNextLogicallyEmptyWeakBlock();
WeakBlock* nextBlock = block->next();
block->sweep();
if (block->isLogicallyEmptyButNotFree()) {
// If this WeakBlock is logically empty, but still has Weaks pointing into it,
// we can't destroy it just yet. Detach it from the WeakSet and hand ownership
// to the Heap so we don't pin down the entire MarkedBlock or PreciseAllocation.
m_blocks.remove(block);
heap()->addLogicallyEmptyWeakBlock(block);
block->disconnectContainer();
}
block = nextBlock;
}
resetAllocator();
}
void WeakSet::shrink()
{
WeakBlock* next;
for (WeakBlock* block = m_blocks.head(); block; block = next) {
next = block->next();
if (block->isEmpty())
removeAllocator(block);
}
resetAllocator();
if (m_blocks.isEmpty() && isOnList())
remove();
}
WeakBlock::FreeCell* WeakSet::findAllocator(CellContainer container)
{
if (WeakBlock::FreeCell* allocator = tryFindAllocator())
return allocator;
return addAllocator(container);
}
WeakBlock::FreeCell* WeakSet::tryFindAllocator()
{
while (m_nextAllocator) {
WeakBlock* block = m_nextAllocator;
m_nextAllocator = m_nextAllocator->next();
WeakBlock::SweepResult sweepResult = block->takeSweepResult();
if (sweepResult.freeList)
return sweepResult.freeList;
}
return nullptr;
}
WeakBlock::FreeCell* WeakSet::addAllocator(CellContainer container)
{
if (!isOnList())
heap()->objectSpace().addActiveWeakSet(this);
WeakBlock* block = WeakBlock::create(*heap(), container);
heap()->didAllocate(WeakBlock::blockSize);
m_blocks.append(block);
WeakBlock::SweepResult sweepResult = block->takeSweepResult();
ASSERT(!sweepResult.isNull() && sweepResult.freeList);
return sweepResult.freeList;
}
void WeakSet::removeAllocator(WeakBlock* block)
{
m_blocks.remove(block);
WeakBlock::destroy(*heap(), block);
}
} // namespace JSC