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      1 /*
      2  * Copyright (C) 2010 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef PageAllocation_h
     27 #define PageAllocation_h
     28 
     29 #include <wtf/Assertions.h>
     30 #include <wtf/OSAllocator.h>
     31 #include <wtf/PageBlock.h>
     32 #include <wtf/UnusedParam.h>
     33 #include <wtf/VMTags.h>
     34 #include <algorithm>
     35 
     36 #if OS(DARWIN)
     37 #include <mach/mach_init.h>
     38 #include <mach/vm_map.h>
     39 #endif
     40 
     41 #if OS(HAIKU)
     42 #include <OS.h>
     43 #endif
     44 
     45 #if OS(WINDOWS)
     46 #include <malloc.h>
     47 #include <windows.h>
     48 #endif
     49 
     50 #if OS(SYMBIAN)
     51 #include <e32hal.h>
     52 #include <e32std.h>
     53 #endif
     54 
     55 #if HAVE(ERRNO_H)
     56 #include <errno.h>
     57 #endif
     58 
     59 #if HAVE(MMAP)
     60 #include <sys/mman.h>
     61 #include <unistd.h>
     62 #endif
     63 
     64 namespace WTF {
     65 
     66 /*
     67     PageAllocation
     68 
     69     The PageAllocation class provides a cross-platform memory allocation interface
     70     with similar capabilities to posix mmap/munmap.  Memory is allocated by calling
     71     PageAllocation::allocate, and deallocated by calling deallocate on the
     72     PageAllocation object.  The PageAllocation holds the allocation's base pointer
     73     and size.
     74 
     75     The allocate method is passed the size required (which must be a multiple of
     76     the system page size, which can be accessed using PageAllocation::pageSize).
     77     Callers may also optinally provide a flag indicating the usage (for use by
     78     system memory usage tracking tools, where implemented), and boolean values
     79     specifying the required protection (defaulting to writable, non-executable).
     80 */
     81 
     82 class PageAllocation : private PageBlock {
     83 public:
     84     PageAllocation()
     85     {
     86     }
     87 
     88     using PageBlock::size;
     89     using PageBlock::base;
     90 
     91 #ifndef __clang__
     92     using PageBlock::operator bool;
     93 #else
     94     // FIXME: This is a workaround for <rdar://problem/8876150>, wherein Clang incorrectly emits an access
     95     // control warning when a client tries to use operator bool exposed above via "using PageBlock::operator bool".
     96     operator bool() const { return PageBlock::operator bool(); }
     97 #endif
     98 
     99     static PageAllocation allocate(size_t size, OSAllocator::Usage usage = OSAllocator::UnknownUsage, bool writable = true, bool executable = false)
    100     {
    101         ASSERT(isPageAligned(size));
    102         return PageAllocation(OSAllocator::reserveAndCommit(size, usage, writable, executable), size);
    103     }
    104 
    105     void deallocate()
    106     {
    107         // Clear base & size before calling release; if this is *inside* allocation
    108         // then we won't be able to clear then after deallocating the memory.
    109         PageAllocation tmp;
    110         std::swap(tmp, *this);
    111 
    112         ASSERT(tmp);
    113         ASSERT(!*this);
    114 
    115         OSAllocator::decommitAndRelease(tmp.base(), tmp.size());
    116     }
    117 
    118 private:
    119     PageAllocation(void* base, size_t size)
    120         : PageBlock(base, size)
    121     {
    122     }
    123 };
    124 
    125 } // namespace WTF
    126 
    127 using WTF::PageAllocation;
    128 
    129 #endif // PageAllocation_h
    130