/*
 * Copyright (C) 2010 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 "OSAllocator.h"

#if OS(UNIX) && !OS(SYMBIAN)

#include <errno.h>
#include <sys/mman.h>
#include <wtf/Assertions.h>
#include <wtf/UnusedParam.h>

namespace WTF {

void* OSAllocator::reserve(size_t bytes)
{
    // From a bookkeeping perspective, POSIX reservations start out in the committed state.
    void* result = mmap(0, bytes, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
    if (result == MAP_FAILED)
        CRASH();
#if HAVE(MADV_FREE_REUSE)
    while (madvise(result, bytes, MADV_FREE_REUSABLE) == -1 && errno == EAGAIN) { }
#endif
    return result;
}

void* OSAllocator::reserveAndCommit(size_t bytes)
{
    // From a bookkeeping perspective, POSIX reservations start out in the committed state.
    return reserve(bytes);
}

void OSAllocator::commit(void* address, size_t bytes)
{
#if HAVE(MADV_FREE_REUSE)
    while (madvise(address, bytes, MADV_FREE_REUSE) == -1 && errno == EAGAIN) { }
#else
    UNUSED_PARAM(address);
    UNUSED_PARAM(bytes);
#endif
}

void OSAllocator::decommit(void* address, size_t bytes)
{
#if HAVE(MADV_FREE_REUSE)
    while (madvise(address, bytes, MADV_FREE_REUSABLE) == -1 && errno == EAGAIN) { }
#elif HAVE(MADV_FREE)
    while (madvise(address, bytes, MADV_FREE) == -1 && errno == EAGAIN) { }
#elif HAVE(MADV_DONTNEED)
    while (madvise(address, bytes, MADV_DONTNEED) == -1 && errno == EAGAIN) { }
#else
    UNUSED_PARAM(address);
    UNUSED_PARAM(bytes);
#endif
}

void OSAllocator::release(void* address, size_t bytes)
{
    munmap(address, bytes);
}

} // namespace WTF

#endif