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// Copyright 2020 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_PERSISTENT_STORAGE_MANAGER_H_
#define COMPONENTS_BREADCRUMBS_CORE_BREADCRUMB_PERSISTENT_STORAGE_MANAGER_H_
#include <optional>
#include <string>
#include <vector>
#include "base/files/file_path.h"
#include "base/functional/callback.h"
#include "base/functional/callback_forward.h"
#include "base/task/sequenced_task_runner.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "components/breadcrumbs/core/breadcrumb_manager.h"
#include "components/breadcrumbs/core/breadcrumb_manager_observer.h"
#include "components/breadcrumbs/core/breadcrumbs_status.h"
#include "components/breadcrumbs/core/crash_reporter_breadcrumb_constants.h"
namespace breadcrumbs {
// The filesize for the file at |breadcrumbs_file_path_|. The file will always
// be this constant size because it is accessed using a memory mapped file. The
// file is twice as large as |kMaxDataLength| which leaves room for appending
// breadcrumb events. Once the file is full of events, the contents will be
// reduced to kMaxDataLength.
constexpr size_t kPersistedFilesizeInBytes = kMaxDataLength * 2;
// Stores breadcrumb events to and retrieves them from a file on disk.
// Persisting these events allows access to breadcrumb events from previous
// application sessions.
class BreadcrumbPersistentStorageManager : public BreadcrumbManagerObserver {
public:
// Observes the BreadcrumbManager and stores observed breadcrumb events to a
// file in `directory`. If a previous session's events are already stored in
// the file, reads them and passes them to the BreadcrumbManager to be
// prepended to the event log.
explicit BreadcrumbPersistentStorageManager(
const base::FilePath& directory,
base::RepeatingCallback<bool()> is_metrics_enabled_callback,
base::OnceClosure initialization_done_callback = base::DoNothing());
~BreadcrumbPersistentStorageManager() override;
BreadcrumbPersistentStorageManager(
const BreadcrumbPersistentStorageManager&) = delete;
BreadcrumbPersistentStorageManager& operator=(
const BreadcrumbPersistentStorageManager&) = delete;
private:
// Sets `file_position_` based on the given `previous_session_events`, and
// passes them to the BreadcrumbManager. If any events have already been
// logged it then writes them to the file.
void Initialize(base::OnceClosure initialization_done_callback,
const std::string& previous_session_events);
// Returns whether metrics consent has been provided and the persistent
// storage manager can therefore create its breadcrumbs files. Deletes any
// existing breadcrumbs files if consent has been revoked.
bool CheckForFileConsent();
// Writes |pending_breadcrumbs_| to |breadcrumbs_file_| if it fits, otherwise
// rewrites the file. NOTE: Writing may be delayed if the file has recently
// been written into.
void WriteEvents(base::OnceClosure done_callback = base::DoNothing());
// Writes the given `events` to `breadcrumbs_file_`. If `append` is false,
// overwrites the file.
void Write(const std::string& events, bool append);
// BreadcrumbManagerObserver
void EventAdded(const std::string& event) override;
// Individual breadcrumbs that have not yet been written to disk.
std::string pending_breadcrumbs_;
// The last time a breadcrumb was written to |breadcrumbs_file_|. This
// timestamp prevents breadcrumbs from being written to disk too often.
base::TimeTicks last_written_time_;
// A timer to delay writing to disk too often.
base::OneShotTimer write_timer_;
// The path to the file for storing persisted breadcrumbs.
const base::FilePath breadcrumbs_file_path_;
// The current size of breadcrumbs written to |breadcrumbs_file_path_|.
// NOTE: The optional will not have a value until the size of the existing
// file, if any, is retrieved.
std::optional<size_t> file_position_;
// Used to check whether the user has consented to metrics reporting.
// Breadcrumbs should only be written to persistent storage if true.
base::RepeatingCallback<bool()> is_metrics_enabled_callback_;
// The SequencedTaskRunner on which File IO operations are performed.
scoped_refptr<base::SequencedTaskRunner> task_runner_;
base::WeakPtrFactory<BreadcrumbPersistentStorageManager> weak_ptr_factory_;
};
} // namespace breadcrumbs
#endif // COMPONENTS_BREADCRUMBS_CORE_BREADCRUMB_PERSISTENT_STORAGE_MANAGER_H_
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