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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_APPS_ALMANAC_API_CLIENT_PROTO_FILE_MANAGER_H_
#define CHROME_BROWSER_APPS_ALMANAC_API_CLIENT_PROTO_FILE_MANAGER_H_
#include <optional>
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/functional/callback_forward.h"
#include "base/logging.h"
#include "base/memory/scoped_refptr.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/task_traits.h"
#include "base/task/thread_pool.h"
namespace apps {
// Writes a file to a given `path` on disk. If the write operation fails,
// the existing data on disk will be unaffected. Returns true if data is
// written to disk successfully and false otherwise.
bool WriteFileToDisk(const base::FilePath& path, const std::string& data);
// The ProtoFileManager is used to store protos on disk
// and read the stored data from disk.
template <typename M>
class ProtoFileManager {
public:
explicit ProtoFileManager(base::FilePath& path)
: path_(path),
task_runner_(base::ThreadPool::CreateSequencedTaskRunner(
{base::MayBlock(), base::TaskPriority::BEST_EFFORT,
base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN})) {}
~ProtoFileManager() = default;
ProtoFileManager(const ProtoFileManager&) = delete;
ProtoFileManager& operator=(const ProtoFileManager&) = delete;
// Writes proto data to a file on disk using another thread.
void WriteProtoToFile(M proto, base::OnceCallback<void(bool)> callback) {
// Write is a blocking function, so the task is posted to another thread.
task_runner_->PostTaskAndReplyWithResult(
FROM_HERE,
base::BindOnce(
[](const base::FilePath& path, const M& proto) {
return WriteFileToDisk(path, proto.SerializeAsString());
},
path_, std::move(proto)),
std::move(callback));
}
// Reads proto data from the file path on disk using another thread.
void ReadProtoFromFile(base::OnceCallback<void(std::optional<M>)> callback) {
// Read is a blocking function, so the task is posted to another thread.
task_runner_->PostTaskAndReplyWithResult(
FROM_HERE,
base::BindOnce(
[](const base::FilePath& path) -> std::optional<M> {
std::string serialized_data;
if (!base::ReadFileToString(path, &serialized_data)) {
LOG(ERROR) << "Reading file from disk failed: " << path.value();
return std::nullopt;
}
M proto;
if (!proto.ParseFromString(serialized_data)) {
LOG(ERROR) << "Parsing proto failed: " << path.value();
return std::nullopt;
}
return proto;
},
path_),
std::move(callback));
}
private:
// Absolute path to the file where data is stored.
base::FilePath path_;
scoped_refptr<base::SequencedTaskRunner> task_runner_;
};
} // namespace apps
#endif // CHROME_BROWSER_APPS_ALMANAC_API_CLIENT_PROTO_FILE_MANAGER_H_
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