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/*
* 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. ``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.
*/
#ifndef PageAllocation_h
#define PageAllocation_h
#include <wtf/Assertions.h>
#include <wtf/OSAllocator.h>
#include <wtf/PageBlock.h>
#include <wtf/UnusedParam.h>
#include <wtf/VMTags.h>
#include <algorithm>
#if OS(DARWIN)
#include <mach/mach_init.h>
#include <mach/vm_map.h>
#endif
#if OS(WINDOWS)
#include <malloc.h>
#include <windows.h>
#endif
#if HAVE(ERRNO_H)
#include <errno.h>
#endif
#if HAVE(MMAP)
#include <sys/mman.h>
#include <unistd.h>
#endif
namespace WTF {
/*
PageAllocation
The PageAllocation class provides a cross-platform memory allocation interface
with similar capabilities to posix mmap/munmap. Memory is allocated by calling
PageAllocation::allocate, and deallocated by calling deallocate on the
PageAllocation object. The PageAllocation holds the allocation's base pointer
and size.
The allocate method is passed the size required (which must be a multiple of
the system page size, which can be accessed using PageAllocation::pageSize).
Callers may also optinally provide a flag indicating the usage (for use by
system memory usage tracking tools, where implemented), and boolean values
specifying the required protection (defaulting to writable, non-executable).
*/
class PageAllocation : private PageBlock {
public:
PageAllocation()
{
}
using PageBlock::size;
using PageBlock::base;
#ifndef __clang__
using PageBlock::operator bool;
#else
// FIXME: This is a workaround for <rdar://problem/8876150>, wherein Clang incorrectly emits an access
// control warning when a client tries to use operator bool exposed above via "using PageBlock::operator bool".
operator bool() const { return PageBlock::operator bool(); }
#endif
bool operator<(const PageAllocation &b) { return base() < b.base(); }
static PageAllocation allocate(size_t size,
OSAllocator::Usage usage = OSAllocator::UnknownUsage,
bool writable = true, bool executable = false,
bool includesGuardPages = false)
{
ASSERT(isPageAligned(size));
return PageAllocation(OSAllocator::reserveAndCommit(size, usage, writable, executable,
includesGuardPages), size,
includesGuardPages);
}
void deallocate()
{
// Clear base & size before calling release; if this is *inside* allocation
// then we won't be able to clear then after deallocating the memory.
PageAllocation tmp;
std::swap(tmp, *this);
ASSERT(tmp);
ASSERT(!*this);
OSAllocator::decommitAndRelease(tmp.realBase(), tmp.realSize());
}
private:
PageAllocation(void* base, size_t size, bool includesGuardPages = false)
: PageBlock(base, size, includesGuardPages)
{
}
};
} // namespace WTF
using WTF::PageAllocation;
#endif // PageAllocation_h
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