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// Copyright 2017 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_COMMON_NOTIFICATIONS_NOTIFICATION_IMAGE_RETAINER_H_
#define CHROME_COMMON_NOTIFICATIONS_NOTIFICATION_IMAGE_RETAINER_H_
#include <memory>
#include <utility>
#include <vector>
#include "base/files/file_path.h"
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "base/task/sequenced_task_runner.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
namespace gfx {
class Image;
} // namespace gfx
// The purpose of this class is to take data from memory, store it to disk as
// temp files and keep them alive long enough to hand over to external entities,
// such as the Action Center on Windows. The Action Center will read the files
// at some point in the future, which is why we can't do:
// [write file] -> [show notification] -> [delete file].
//
// Also, on Windows, temp file deletion is not guaranteed and, since the images
// can potentially be large, this presents a problem because Chrome might then
// be leaving chunks of dead bits lying around on users' computers during
// unclean shutdowns.
class NotificationImageRetainer {
public:
NotificationImageRetainer(
scoped_refptr<base::SequencedTaskRunner> deletion_task_runner,
const base::TickClock* tick_clock);
NotificationImageRetainer(const NotificationImageRetainer&) = delete;
NotificationImageRetainer& operator=(const NotificationImageRetainer&) =
delete;
NotificationImageRetainer();
virtual ~NotificationImageRetainer();
// Deletes all the remaining files in image_dir_ due to previous unclean
// shutdowns.
virtual void CleanupFilesFromPrevSessions();
// Stores an |image| on disk in a temporary (short-lived) file. Returns the
// path to the file created, which will be valid for a few seconds only. It
// will be deleted either after a short timeout or after a restart of Chrome.
// The function returns an empty FilePath if file creation fails.
virtual base::FilePath RegisterTemporaryImage(const gfx::Image& image);
// Returns a closure that, when run, performs cleanup operations. This closure
// must be run on the notification sequence.
base::OnceClosure GetCleanupTask();
const base::FilePath& image_dir() { return image_dir_; }
private:
using NameAndTime = std::pair<base::FilePath, base::TimeTicks>;
using NamesAndTimes = std::vector<NameAndTime>;
// Deletes expired (older than a pre-defined threshold) files.
void DeleteExpiredFiles();
// A collection of names (note: not full paths) to registered image files
// in image_dir_, each of which must stay valid for a short time while the
// Notification Center processes them. Each file has a corresponding
// registration timestamp. Files in this collection that have outlived the
// required minimum lifespan are scheduled for deletion periodically by
// |deletion_timer_|. The items in this collection are sorted by increasing
// registration time.
NamesAndTimes registered_images_;
// The task runner used to handle file deletion.
scoped_refptr<base::SequencedTaskRunner> deletion_task_runner_;
// The path to where to store the temporary files.
const base::FilePath image_dir_;
// Not owned.
const raw_ptr<const base::TickClock> tick_clock_;
// A timer used to handle deleting files in batch.
base::RepeatingTimer deletion_timer_;
SEQUENCE_CHECKER(sequence_checker_);
// For callbacks may run after destruction.
base::WeakPtrFactory<NotificationImageRetainer> weak_ptr_factory_{this};
};
#endif // CHROME_COMMON_NOTIFICATIONS_NOTIFICATION_IMAGE_RETAINER_H_
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