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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/files/memory_mapped_file.h"
#include <utility>
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/sys_info.h"
#include "build/build_config.h"
namespace base {
const MemoryMappedFile::Region MemoryMappedFile::Region::kWholeFile = {0, 0};
bool MemoryMappedFile::Region::operator==(
const MemoryMappedFile::Region& other) const {
return other.offset == offset && other.size == size;
}
bool MemoryMappedFile::Region::operator!=(
const MemoryMappedFile::Region& other) const {
return other.offset != offset || other.size != size;
}
MemoryMappedFile::~MemoryMappedFile() {
CloseHandles();
}
#if !defined(OS_NACL)
bool MemoryMappedFile::Initialize(const FilePath& file_name) {
if (IsValid())
return false;
file_.Initialize(file_name, File::FLAG_OPEN | File::FLAG_READ);
if (!file_.IsValid()) {
DLOG(ERROR) << "Couldn't open " << file_name.AsUTF8Unsafe();
return false;
}
if (!MapFileRegionToMemory(Region::kWholeFile)) {
CloseHandles();
return false;
}
return true;
}
bool MemoryMappedFile::Initialize(File file) {
return Initialize(std::move(file), Region::kWholeFile);
}
bool MemoryMappedFile::Initialize(File file, const Region& region) {
if (IsValid())
return false;
if (region != Region::kWholeFile) {
DCHECK_GE(region.offset, 0);
DCHECK_GT(region.size, 0);
}
file_ = std::move(file);
if (!MapFileRegionToMemory(region)) {
CloseHandles();
return false;
}
return true;
}
bool MemoryMappedFile::IsValid() const {
return data_ != NULL;
}
// static
void MemoryMappedFile::CalculateVMAlignedBoundaries(int64_t start,
int64_t size,
int64_t* aligned_start,
int64_t* aligned_size,
int32_t* offset) {
// Sadly, on Windows, the mmap alignment is not just equal to the page size.
const int64_t mask =
static_cast<int64_t>(SysInfo::VMAllocationGranularity()) - 1;
DCHECK_LT(mask, std::numeric_limits<int32_t>::max());
*offset = start & mask;
*aligned_start = start & ~mask;
*aligned_size = (size + *offset + mask) & ~mask;
}
#endif
} // namespace base
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