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#pragma once
27
28#include <wtf/Assertions.h>
29#include <wtf/OSAllocator.h>
30#include <wtf/PageBlock.h>
31#include <algorithm>
32
33#if OS(DARWIN)
34#include <mach/mach_init.h>
35#include <mach/vm_map.h>
36#endif
37
38#if OS(WINDOWS)
39#include <malloc.h>
40#include <windows.h>
41#endif
42
43#if HAVE(ERRNO_H)
44#include <errno.h>
45#endif
46
47#if HAVE(MMAP)
48#include <sys/mman.h>
49#include <unistd.h>
50#endif
51
52namespace WTF {
53
54/*
55 PageAllocation
56
57 The PageAllocation class provides a cross-platform memory allocation interface
58 with similar capabilities to posix mmap/munmap. Memory is allocated by calling
59 PageAllocation::allocate, and deallocated by calling deallocate on the
60 PageAllocation object. The PageAllocation holds the allocation's base pointer
61 and size.
62
63 The allocate method is passed the size required (which must be a multiple of
64 the system page size, which can be accessed using PageAllocation::pageSize).
65 Callers may also optinally provide a flag indicating the usage (for use by
66 system memory usage tracking tools, where implemented), and boolean values
67 specifying the required protection (defaulting to writable, non-executable).
68*/
69
70class PageAllocation : private PageBlock {
71public:
72 PageAllocation()
73 {
74 }
75
76 using PageBlock::size;
77 using PageBlock::base;
78
79#ifndef __clang__
80 using PageBlock::operator bool;
81#else
82 // FIXME: This is a workaround for <rdar://problem/8876150>, wherein Clang incorrectly emits an access
83 // control warning when a client tries to use operator bool exposed above via "using PageBlock::operator bool".
84 operator bool() const { return PageBlock::operator bool(); }
85#endif
86
87 static PageAllocation allocate(size_t size, OSAllocator::Usage usage = OSAllocator::UnknownUsage, bool writable = true, bool executable = false)
88 {
89 ASSERT(isPageAligned(size));
90 return PageAllocation(OSAllocator::reserveAndCommit(size, usage, writable, executable), size);
91 }
92
93 void deallocate()
94 {
95 // Clear base & size before calling release; if this is *inside* allocation
96 // then we won't be able to clear then after deallocating the memory.
97 PageAllocation tmp;
98 std::swap(tmp, *this);
99
100 ASSERT(tmp);
101 ASSERT(!*this);
102
103 OSAllocator::decommitAndRelease(tmp.base(), tmp.size());
104 }
105
106private:
107 PageAllocation(void* base, size_t size)
108 : PageBlock(base, size, false)
109 {
110 }
111};
112
113} // namespace WTF
114
115using WTF::PageAllocation;
116