/*
 * Copyright (C) 2016-2020 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 "HeapCell.h"

#include "HeapCellInlines.h"
#include "MarkedBlockInlines.h"
#include <wtf/PrintStream.h>

namespace JSC {

// isPendingDestruction must not be called on a freed (i.e. already destructed) HeapCell
// since the backing MarkedBlock may have been freed too.
bool HeapCell::isPendingDestruction()
{
    if (isPreciseAllocation())
        return !preciseAllocation().isLive();
    auto& markedBlockHandle = markedBlock().handle();
    // If the block is freelisted then either:
    // (1) The cell is not on the FreeList, in which case it is newly allocated or
    // (2) The cell is on the FreeList, in which case it is free.
    // In either case, the destructor is not pending.
    // (And as indicated above, it's not legal to call this method in state #2).
    if (markedBlockHandle.isFreeListed())
        return false;
    return !markedBlockHandle.isLive(this);
}

} // namespace JSC

namespace WTF {

using namespace JSC;

void printInternal(PrintStream& out, HeapCell::Kind kind)
{
    switch (kind) {
    case HeapCell::JSCell:
        out.print("JSCell");
        return;
    case HeapCell::JSCellWithIndexingHeader:
        out.print("JSCellWithIndexingHeader");
        return;
    case HeapCell::Auxiliary:
        out.print("Auxiliary");
        return;
    }
    RELEASE_ASSERT_NOT_REACHED();
}

} // namespace WTF

