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92 lines
2.3 KiB
C++
92 lines
2.3 KiB
C++
// Copyright 2013 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/files/memory_mapped_file.h"
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#include "base/files/file_path.h"
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#include "base/logging.h"
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#include "base/sys_info.h"
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namespace base {
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const MemoryMappedFile::Region MemoryMappedFile::Region::kWholeFile = {0, 0};
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bool MemoryMappedFile::Region::operator==(
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const MemoryMappedFile::Region& other) const {
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return other.offset == offset && other.size == size;
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}
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bool MemoryMappedFile::Region::operator!=(
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const MemoryMappedFile::Region& other) const {
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return other.offset != offset || other.size != size;
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}
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MemoryMappedFile::~MemoryMappedFile() {
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CloseHandles();
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}
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#if !defined(OS_NACL)
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bool MemoryMappedFile::Initialize(const FilePath& file_name) {
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if (IsValid())
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return false;
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file_.Initialize(file_name, File::FLAG_OPEN | File::FLAG_READ);
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if (!file_.IsValid()) {
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DLOG(ERROR) << "Couldn't open " << file_name.AsUTF8Unsafe();
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return false;
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}
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if (!MapFileRegionToMemory(Region::kWholeFile)) {
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CloseHandles();
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return false;
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}
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return true;
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}
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bool MemoryMappedFile::Initialize(File file) {
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return Initialize(file.Pass(), Region::kWholeFile);
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}
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bool MemoryMappedFile::Initialize(File file, const Region& region) {
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if (IsValid())
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return false;
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if (region != Region::kWholeFile) {
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DCHECK_GE(region.offset, 0);
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DCHECK_GT(region.size, 0);
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}
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file_ = file.Pass();
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if (!MapFileRegionToMemory(region)) {
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CloseHandles();
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return false;
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}
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return true;
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}
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bool MemoryMappedFile::IsValid() const {
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return data_ != NULL;
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}
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// static
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void MemoryMappedFile::CalculateVMAlignedBoundaries(int64 start,
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int64 size,
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int64* aligned_start,
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int64* aligned_size,
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int32* offset) {
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// Sadly, on Windows, the mmap alignment is not just equal to the page size.
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const int64 mask = static_cast<int64>(SysInfo::VMAllocationGranularity()) - 1;
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DCHECK_LT(mask, std::numeric_limits<int32>::max());
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*offset = start & mask;
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*aligned_start = start & ~mask;
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*aligned_size = (size + *offset + mask) & ~mask;
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}
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#endif
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} // namespace base
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