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// Copyright 2024 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_SUPERVISED_USER_CORE_BROWSER_PARALLEL_FETCH_MANAGER_H_
#define COMPONENTS_SUPERVISED_USER_CORE_BROWSER_PARALLEL_FETCH_MANAGER_H_
#include <memory>
#include "base/containers/id_map.h"
#include "base/functional/callback.h"
#include "base/memory/weak_ptr.h"
#include "components/supervised_user/core/browser/proto_fetcher.h"
namespace supervised_user {
// Component for managing multiple fetches at once.
//
// After each fetch, the reference kept in internal map is cleared. This will
// also happen when this manager is destroyed. In the latter case, callbacks
// won't be executed (the pending requests will be canceled).
template <typename Request, typename Response>
class ParallelFetchManager {
private:
using Fetcher = ProtoFetcher<Response>;
using KeyType = base::IDMap<std::unique_ptr<Fetcher>>::KeyType;
public:
// Provides fresh instances of a started fetcher for each fetch.
using FetcherFactory = base::RepeatingCallback<std::unique_ptr<Fetcher>(
const Request&,
typename Fetcher::Callback callback)>;
ParallelFetchManager() = delete;
explicit ParallelFetchManager(FetcherFactory fetcher_factory)
: fetcher_factory_(fetcher_factory) {}
ParallelFetchManager(const ParallelFetchManager&) = delete;
ParallelFetchManager& operator=(const ParallelFetchManager&) = delete;
~ParallelFetchManager() = default;
// Starts the fetch. Underlying fetcher is stored internally, and will be
// cleaned up after finish or when this manager is destroyed.
void Fetch(const Request& request, Fetcher::Callback callback) {
CHECK(callback) << "Use base::DoNothing() instead of empty callback.";
KeyType key = ++id_;
typename Fetcher::Callback callback_with_cleanup =
std::move(callback).Then(base::BindOnce(
&ParallelFetchManager::Remove, weak_factory_.GetWeakPtr(), key));
requests_in_flight_.AddWithID(
fetcher_factory_.Run(request, std::move(callback_with_cleanup)), key);
}
private:
// Remove fetcher under key from requests_in_flight_.
void Remove(KeyType key) { requests_in_flight_.Remove(key); }
base::IDMap<std::unique_ptr<Fetcher>, KeyType> requests_in_flight_;
KeyType id_{0};
FetcherFactory fetcher_factory_;
base::WeakPtrFactory<ParallelFetchManager<Request, Response>> weak_factory_{
this};
};
} // namespace supervised_user
#endif // COMPONENTS_SUPERVISED_USER_CORE_BROWSER_PARALLEL_FETCH_MANAGER_H_
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