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// Copyright 2019 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_BREADCRUMBS_CORE_BREADCRUMB_MANAGER_H_
#define COMPONENTS_BREADCRUMBS_CORE_BREADCRUMB_MANAGER_H_
#include <string>
#include "base/containers/circular_deque.h"
#include "base/no_destructor.h"
#include "base/observer_list.h"
#include "base/time/time.h"
namespace breadcrumbs {
class BreadcrumbManagerObserver;
// The maximum number of breadcrumbs to keep track of. Once this is reached,
// the oldest breadcrumbs will be dropped.
extern const size_t kMaxBreadcrumbs;
// Stores events logged with `AddEvent` in memory, which can later be retrieved
// with `GetEvents`.
class BreadcrumbManager {
public:
// Returns the singleton BreadcrumbManager. Creates it if it does not exist.
static BreadcrumbManager& GetInstance();
BreadcrumbManager(const BreadcrumbManager&) = delete;
BreadcrumbManager& operator=(const BreadcrumbManager&) = delete;
// Returns the current list of collected breadcrumb events. Events returned
// will have a timestamp prepended, representing when each event was added.
// Calling `AddEvents()` will invalidate iterators pointing to the list.
const base::circular_deque<std::string>& GetEvents();
// Logs a breadcrumb event with message data `event`. Drops the oldest stored
// event if needed to keep the number of events below `kMaxBreadcrumbs`.
// `event` must not include newline characters as newlines are used by
// BreadcrumbPersistentStorageManager as a delimiter.
void AddEvent(const std::string& event);
// Adds breadcrumb events associated with the previous application session.
// Note: this behaves the same as `AddEvent()`, but takes multiple events and
// adds them to the start of the breadcrumbs log.
void SetPreviousSessionEvents(const std::vector<std::string>& events);
// Adds and removes observers.
void AddObserver(BreadcrumbManagerObserver* observer);
void RemoveObserver(BreadcrumbManagerObserver* observer);
// Resets timestamps to 0:00:00 and removes all events. Does not remove
// observers or notify observers about removed events.
void ResetForTesting();
private:
friend class base::NoDestructor<BreadcrumbManager>;
BreadcrumbManager();
~BreadcrumbManager();
// Returns the time since `start_time_`.
base::TimeDelta GetElapsedTime();
// The time when breadcrumbs logging started, used to calculate elapsed time
// for event timestamps.
base::TimeTicks start_time_ = base::TimeTicks::Now();
// List of event strings, up to a maximum of `kMaxBreadcrumbs`. Newer events
// are at the end.
base::circular_deque<std::string> breadcrumbs_;
base::ObserverList<BreadcrumbManagerObserver, /*check_empty=*/true>
observers_;
};
} // namespace breadcrumbs
#endif // COMPONENTS_BREADCRUMBS_CORE_BREADCRUMB_MANAGER_H_
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