Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/PageReservation.h

-/*
- * 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 PageReservation_h
-#define PageReservation_h
-
-#include <wtf/PageAllocation.h>
-
-namespace WTF {
-
-/*
-    PageReservation
-
-    Like PageAllocation, the PageReservation class provides a cross-platform memory
-    allocation interface, but with a set of capabilities more similar to that of
-    VirtualAlloc than posix mmap.  PageReservation can be used to allocate virtual
-    memory without committing physical memory pages using PageReservation::reserve.
-    Following a call to reserve all memory in the region is in a decommited state,
-    in which the memory should not be used (accessing the memory may cause a fault).
-
-    Before using memory it must be committed by calling commit, which is passed start
-    and size values (both of which require system page size granularity).  One the
-    committed memory is no longer needed 'decommit' may be called to return the
-    memory to its devommitted state.  Commit should only be called on memory that is
-    currently decommitted, and decommit should only be called on memory regions that
-    are currently committed.  All memory should be decommited before the reservation
-    is deallocated.  Values in memory may not be retained accross a pair of calls if
-    the region of memory is decommitted and then committed again.
-
-    Memory protection should not be changed on decommitted memory, and if protection
-    is changed on memory while it is committed it should be returned to the orignal
-    protection before decommit is called.
-*/
-
-class PageReservation : private PageBlock {
-public:
-    PageReservation()
-        : m_committed(0)
-        , m_writable(false)
-        , m_executable(false)
-    {
-    }
-
-    using PageBlock::base;
-    using PageBlock::size;
-
-#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
-
-    void commit(void* start, size_t size)
-    {
-        ASSERT(*this);
-        ASSERT(isPageAligned(start));
-        ASSERT(isPageAligned(size));
-        ASSERT(contains(start, size));
-
-        m_committed += size;
-        OSAllocator::commit(start, size, m_writable, m_executable);
-    }
-
-    void decommit(void* start, size_t size)
-    {
-        ASSERT(*this);
-        ASSERT(isPageAligned(start));
-        ASSERT(isPageAligned(size));
-        ASSERT(contains(start, size));
-
-        m_committed -= size;
-        OSAllocator::decommit(start, size);
-    }
-
-    size_t committed()
-    {
-        return m_committed;
-    }
-
-    static PageReservation reserve(size_t size, OSAllocator::Usage usage = OSAllocator::UnknownUsage, bool writable = true, bool executable = false)
-    {
-        ASSERT(isPageAligned(size));
-        return PageReservation(OSAllocator::reserveUncommitted(size, usage, writable, executable), size, writable, executable, false);
-    }
-    
-    static PageReservation reserveWithGuardPages(size_t size, OSAllocator::Usage usage = OSAllocator::UnknownUsage, bool writable = true, bool executable = false)
-    {
-        ASSERT(isPageAligned(size));
-        return PageReservation(OSAllocator::reserveUncommitted(size + pageSize() * 2, usage, writable, executable, true), size, writable, executable, true);
-    }
-
-    void deallocate()
-    {
-        ASSERT(!m_committed);
-
-        // Clear base & size before calling release; if this is *inside* allocation
-        // then we won't be able to clear then after deallocating the memory.
-        PageReservation tmp;
-        std::swap(tmp, *this);
-
-        ASSERT(tmp);
-        ASSERT(!*this);
-
-        OSAllocator::releaseDecommitted(tmp.base(), tmp.size());
-    }
-
-private:
-    PageReservation(void* base, size_t size, bool writable, bool executable, bool hasGuardPages)
-        : PageBlock(base, size, hasGuardPages)
-        , m_committed(0)
-        , m_writable(writable)
-        , m_executable(executable)
-    {
-    }
-
-    size_t m_committed;
-    bool m_writable;
-    bool m_executable;
-};
-
-}
-
-using WTF::PageReservation;
-
-#endif // PageReservation_h