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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_BASE_UNIQUE_NOTIFIER_H_
#define CC_BASE_UNIQUE_NOTIFIER_H_
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "cc/base/base_export.h"
namespace base {
class SequencedTaskRunner;
} // namespace base
namespace cc {
// Callers must ensure that they only schedule the notifier on the same thread
// that the provided |task_runner| runs on.
class CC_BASE_EXPORT UniqueNotifier {
public:
// Configure this notifier to issue the |closure| notification when scheduled.
UniqueNotifier(base::SequencedTaskRunner* task_runner,
base::RepeatingClosure closure);
UniqueNotifier(const UniqueNotifier&) = delete;
// Destroying the notifier will ensure that no further notifications will
// happen from this class.
~UniqueNotifier();
UniqueNotifier& operator=(const UniqueNotifier&) = delete;
// Schedule a notification to be run. If another notification is already
// pending, then only one notification will take place.
void Schedule();
// Cancel a pending notification, if one was scheduled.
void Cancel();
private:
void Notify();
// TODO(dcheng): How come this doesn't need to hold a ref to the task runner?
const raw_ptr<base::SequencedTaskRunner> task_runner_;
const base::RepeatingClosure closure_;
// Lock should be held before modifying |notification_pending_|.
base::Lock lock_;
bool notification_pending_;
base::WeakPtrFactory<UniqueNotifier> weak_ptr_factory_{this};
};
} // namespace cc
#endif // CC_BASE_UNIQUE_NOTIFIER_H_
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