wtf/PageAllocation.h

   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, false)
 121     {
 122     }
 123 };
 124
 125 } // namespace WTF
 126
 127 using WTF::PageAllocation;
 128
 129 #endif // PageAllocation_h