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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/device_signals/core/system_signals/hashing_utils.h"
#include <array>
#include <string>
#include <vector>
#include "base/containers/heap_array.h"
#include "base/containers/span.h"
#include "base/files/file.h"
#include "base/files/file_path.h"
#include "base/location.h"
#include "base/memory/page_size.h"
#include "base/threading/scoped_blocking_call.h"
#include "crypto/hash.h"
namespace device_signals {
std::optional<std::string> HashFile(const base::FilePath& file_path) {
base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
base::BlockingType::MAY_BLOCK);
base::File file(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
if (!file.IsValid()) {
return std::nullopt;
}
crypto::hash::Hasher hash(crypto::hash::HashKind::kSha256);
auto buffer = base::HeapArray<uint8_t>::Uninit(base::GetPageSize());
std::optional<size_t> bytes_read;
do {
bytes_read = file.ReadAtCurrentPos(buffer.as_span());
if (!bytes_read.has_value()) {
return std::nullopt;
}
hash.Update(buffer.first(*bytes_read));
} while (bytes_read.value() > 0);
std::string result(crypto::hash::kSha256Size, 0);
hash.Finish(base::as_writable_byte_span(result));
return result;
}
} // namespace device_signals
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