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/*
* Copyright (C) 2024-2025 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.
*/
#pragma once
#if HAVE(MMAP)
#include <sys/mman.h>
#include <wtf/AllocSpanMixin.h>
namespace WTF {
// RAII class for allocating and holding mmap memory with std::span access.
template<typename T> class MmapSpan : public AllocSpanMixin<T> {
public:
static MmapSpan tryAlloc(size_t sizeInBytes)
{
return mmap(nullptr, sizeInBytes, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1);
}
static MmapSpan mmap(void* addr, size_t size, int pageProtection, int options, int fileDescriptor)
{
auto* data = ::mmap(addr, size, pageProtection, options, fileDescriptor, 0);
if (data == MAP_FAILED)
return { };
RELEASE_ASSERT((pageProtection & PROT_EXEC) || WTF_DATA_ADDRESS_IS_SANE(data));
return MmapSpan { data, size };
}
MmapSpan() = default;
MmapSpan(MmapSpan&& other)
: AllocSpanMixin<T>(WTFMove(other))
{
}
template<typename U>
MmapSpan(MmapSpan<U>&& other) requires (std::is_same_v<T, uint8_t>)
: AllocSpanMixin<T>(asWritableBytes(other.leakSpan()))
{
}
~MmapSpan()
{
auto data = this->mutableSpan();
if (data.data())
::munmap(data.data(), data.size());
}
MmapSpan& operator=(MmapSpan&& other)
{
MmapSpan ptr { WTFMove(other) };
this->swap(ptr);
return *this;
}
private:
using AllocSpanMixin<T>::AllocSpanMixin;
};
} // namespace WTF
using WTF::MmapSpan;
#endif // HAVE(MMAP)
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