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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.
#ifndef CHROME_BROWSER_ASH_APP_LIST_SEARCH_BURN_IN_CONTROLLER_H_
#define CHROME_BROWSER_ASH_APP_LIST_SEARCH_BURN_IN_CONTROLLER_H_
#include "ash/public/cpp/app_list/app_list_types.h"
#include "base/containers/flat_map.h"
#include "base/functional/callback.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "chrome/browser/ash/app_list/search/types.h"
namespace app_list {
// Manages operations related to the burn-in period. Owned by the
// SearchController.
class BurnInController {
public:
using BurnInPeriodElapsedCallback = base::RepeatingCallback<void()>;
explicit BurnInController(BurnInPeriodElapsedCallback);
~BurnInController();
BurnInController(const BurnInController&) = delete;
BurnInController& operator=(const BurnInController&) = delete;
// Called at the beginning of a query search. Initiates the burn-in/ period.
void Start();
// Called to stop/interrupt a previous call to Start().
//
// Stops the burn-in timer, thereby preventing any now unneeded calls to
// BurnInPeriodElapsedCallback. Currently, the only use case for this is when
// a query search is succeeded by a zero-state search.
void Stop();
// Called when new result information has become available.
//
// Performs house-keeping related to burn-in iteration numbers for categories
// and individual results. These are later important for sorting purposes in
// the SearchController - see further documentation below.
//
// Triggers the BurnInPeriodElapsedCallback if it is the first time
// UpdateResults() has been called since the burn-in period has elapsed.
//
// Returns true if results are updated before `burn_in_period_`, and false
// otherwise.
bool UpdateResults(ResultsMap& results,
CategoriesList& categories,
ash::AppListSearchResultType result_type);
const base::flat_map<std::string, int>& ids_to_burn_in_iteration_for_test() {
return ids_to_burn_in_iteration_;
}
private:
// The time when Start was most recently called.
base::Time session_start_;
// Called when the burn-in period has elapsed.
BurnInPeriodElapsedCallback burn_in_period_elapsed_callback_;
// The period of time ("burn-in") to wait before publishing a first collection
// of search results to the model updater.
const base::TimeDelta burn_in_period_;
// A timer for the burn-in period. During the burn-in period, results are
// collected from search providers. Publication of results to the model
// updater is delayed until the burn-in period has elapsed.
base::RetainingOneShotTimer burn_in_timer_;
// Counter for burn-in iterations. Useful for query search only.
//
// Zero signifies pre-burn-in state. After burn-in period has elapsed, counter
// is incremented by one each time SetResults() is called. This burn-in
// iteration number is used for individual results as well as overall
// categories.
//
// This information is useful because it allows for:
//
// (1) Results and categories to be ranked by different rules depending on
// whether the information arrived pre- or post-burn-in.
// (2) Sorting stability across multiple post-burn-in updates.
int burn_in_iteration_counter_ = 0;
// Store the ID of each result we encounter in a given query, along with the
// burn-in iteration during which it arrived. This storage is necessary
// because:
//
// Some providers may return more than once, and on each successive return,
// the previous results are swapped for new ones within SetResults(). Result
// meta-information we wish to persist across multiple calls to SetResults
// must therefore be stored separately.
base::flat_map<std::string, int> ids_to_burn_in_iteration_;
};
} // namespace app_list
#endif // CHROME_BROWSER_ASH_APP_LIST_SEARCH_BURN_IN_CONTROLLER_H_
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