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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_VALUE_STORE_VALUE_STORE_FRONTEND_H_
#define COMPONENTS_VALUE_STORE_VALUE_STORE_FRONTEND_H_
#include <optional>
#include <string>
#include "base/functional/callback.h"
#include "base/memory/ref_counted.h"
#include "base/values.h"
namespace base {
class FilePath;
class SequencedTaskRunner;
} // namespace base
namespace value_store {
class ValueStoreFactory;
// A frontend for a LeveldbValueStore, for use on the UI thread.
class ValueStoreFrontend {
public:
using ReadCallback = base::OnceCallback<void(std::optional<base::Value>)>;
ValueStoreFrontend(
const scoped_refptr<ValueStoreFactory>& store_factory,
const base::FilePath& directory,
const std::string& uma_client_name,
const scoped_refptr<base::SequencedTaskRunner>& origin_task_runner,
const scoped_refptr<base::SequencedTaskRunner>& file_task_runner);
~ValueStoreFrontend();
ValueStoreFrontend(const ValueStoreFrontend&) = delete;
ValueStoreFrontend& operator=(const ValueStoreFrontend&) = delete;
// Retrieves a value from the database asynchronously, passing a copy to
// |callback| when ready. NULL is passed if no matching entry is found.
void Get(const std::string& key, ReadCallback callback);
// Sets a value with the given key.
void Set(const std::string& key, base::Value value);
// Removes the value with the given key.
void Remove(const std::string& key);
private:
class Backend;
// A helper class to manage lifetime of the backing ValueStore, which lives
// on the FILE thread.
scoped_refptr<Backend> backend_;
// The task runner on which to fire callbacks.
scoped_refptr<base::SequencedTaskRunner> origin_task_runner_;
scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
};
} // namespace value_store
#endif // COMPONENTS_VALUE_STORE_VALUE_STORE_FRONTEND_H_
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