1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/memory/mozalloc/VolatileBufferWindows.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,157 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#if defined(XP_WIN)
1.9 +# define MOZALLOC_EXPORT __declspec(dllexport)
1.10 +#endif
1.11 +
1.12 +#include "VolatileBuffer.h"
1.13 +#include "mozilla/Assertions.h"
1.14 +#include "mozilla/mozalloc.h"
1.15 +#include "mozilla/WindowsVersion.h"
1.16 +
1.17 +#include <windows.h>
1.18 +
1.19 +#ifdef MOZ_MEMORY
1.20 +extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size);
1.21 +#endif
1.22 +
1.23 +#ifndef MEM_RESET_UNDO
1.24 +#define MEM_RESET_UNDO 0x1000000
1.25 +#endif
1.26 +
1.27 +#define MIN_VOLATILE_ALLOC_SIZE 8192
1.28 +
1.29 +namespace mozilla {
1.30 +
1.31 +VolatileBuffer::VolatileBuffer()
1.32 + : mBuf(nullptr)
1.33 + , mSize(0)
1.34 + , mLockCount(0)
1.35 + , mHeap(false)
1.36 + , mFirstLock(true)
1.37 +{
1.38 +}
1.39 +
1.40 +bool
1.41 +VolatileBuffer::Init(size_t aSize, size_t aAlignment)
1.42 +{
1.43 + MOZ_ASSERT(!mSize && !mBuf, "Init called twice");
1.44 + MOZ_ASSERT(!(aAlignment % sizeof(void *)),
1.45 + "Alignment must be multiple of pointer size");
1.46 +
1.47 + mSize = aSize;
1.48 + if (aSize < MIN_VOLATILE_ALLOC_SIZE) {
1.49 + goto heap_alloc;
1.50 + }
1.51 +
1.52 + static bool sUndoSupported = IsWin8OrLater();
1.53 + if (!sUndoSupported) {
1.54 + goto heap_alloc;
1.55 + }
1.56 +
1.57 + mBuf = VirtualAllocEx(GetCurrentProcess(),
1.58 + nullptr,
1.59 + mSize,
1.60 + MEM_COMMIT | MEM_RESERVE,
1.61 + PAGE_READWRITE);
1.62 + if (mBuf) {
1.63 + return true;
1.64 + }
1.65 +
1.66 +heap_alloc:
1.67 +#ifdef MOZ_MEMORY
1.68 + posix_memalign(&mBuf, aAlignment, aSize);
1.69 +#else
1.70 + mBuf = _aligned_malloc(aSize, aAlignment);
1.71 +#endif
1.72 + mHeap = true;
1.73 + return !!mBuf;
1.74 +}
1.75 +
1.76 +VolatileBuffer::~VolatileBuffer()
1.77 +{
1.78 + if (OnHeap()) {
1.79 +#ifdef MOZ_MEMORY
1.80 + free(mBuf);
1.81 +#else
1.82 + _aligned_free(mBuf);
1.83 +#endif
1.84 + } else {
1.85 + VirtualFreeEx(GetCurrentProcess(), mBuf, 0, MEM_RELEASE);
1.86 + }
1.87 +}
1.88 +
1.89 +bool
1.90 +VolatileBuffer::Lock(void** aBuf)
1.91 +{
1.92 + MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
1.93 +
1.94 + *aBuf = mBuf;
1.95 + if (++mLockCount > 1 || OnHeap()) {
1.96 + return true;
1.97 + }
1.98 +
1.99 + // MEM_RESET_UNDO's behavior is undefined when called on memory that
1.100 + // hasn't been MEM_RESET.
1.101 + if (mFirstLock) {
1.102 + mFirstLock = false;
1.103 + return true;
1.104 + }
1.105 +
1.106 + void* addr = VirtualAllocEx(GetCurrentProcess(),
1.107 + mBuf,
1.108 + mSize,
1.109 + MEM_RESET_UNDO,
1.110 + PAGE_READWRITE);
1.111 + return !!addr;
1.112 +}
1.113 +
1.114 +void
1.115 +VolatileBuffer::Unlock()
1.116 +{
1.117 + MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!");
1.118 + if (--mLockCount || OnHeap()) {
1.119 + return;
1.120 + }
1.121 +
1.122 + void* addr = VirtualAllocEx(GetCurrentProcess(),
1.123 + mBuf,
1.124 + mSize,
1.125 + MEM_RESET,
1.126 + PAGE_READWRITE);
1.127 + MOZ_ASSERT(addr, "Failed to MEM_RESET");
1.128 +}
1.129 +
1.130 +bool
1.131 +VolatileBuffer::OnHeap() const
1.132 +{
1.133 + return mHeap;
1.134 +}
1.135 +
1.136 +size_t
1.137 +VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
1.138 +{
1.139 + if (OnHeap()) {
1.140 +#ifdef MOZ_MEMORY
1.141 + return aMallocSizeOf(mBuf);
1.142 +#else
1.143 + return mSize;
1.144 +#endif
1.145 + }
1.146 +
1.147 + return 0;
1.148 +}
1.149 +
1.150 +size_t
1.151 +VolatileBuffer::NonHeapSizeOfExcludingThis() const
1.152 +{
1.153 + if (OnHeap()) {
1.154 + return 0;
1.155 + }
1.156 +
1.157 + return (mSize + 4095) & ~4095;
1.158 +}
1.159 +
1.160 +} // namespace mozilla
